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TECHNICAL FIELD OF THE INVENTION [0001] The invention relates to a system and a method for controlling at least one device, said system comprising at least a controllable unit associated with said at least one device and a plurality of nodes for transmitting control signals to said at least one controllable unit. BRIEF DESCRIPTION OF RELATED ART [0002] In control system including control points, sensors and actuators, such as for example home automation systems, it is of importance to define and establish control rules in order to achieve a control system that fulfils predefined requirements and operates in a consistent way. In order to do this, certain priority requirements are established, e.g. in order to ensure that commands having a higher priority than other ones will be executed immediately and that such commands may prevent lower-prioritized commands from being executed during a certain time period. [0003] Normally, priority levels are arranged in a decreasing manner, e.g. in the order: user security, product or environment protection, user manual control, automatic comfort control. Most home automation technologies are designed in such a manner that when a priority level is activated, all the lower levels are locked. [0004] This may in many instances be suitable, but may not at all times fulfil the needs of the users. In particular, such a solution does not allow a selective approach. BRIEF SUMMARY OF THE INVENTION [0005] The invention relates to a system for controlling at least one device such as for example an operator for a door, a gate, a window, blinds, shutters, a curtain, an awning or a light source said system comprising at least a controllable unit associated with said at least one device and a plurality of nodes for transmitting control signals to said at least one controllable unit wherein said at least one of said control signals comprises priority indications relating to at least one of a plurality of levels, that said at least one controllable unit comprises means for registering said priority setting indications and for storing a corresponding entry relating to said plurality of command levels and means for performing an evaluation based on stored entries. [0006] Hereby, it is achieved that priorities on a plurality of levels and possibly based on input from a plurality of sources may be handled in a logic and consistent manner. Further, it is achieved that a selective mask may be defined for the operation of the controllable units in the system. [0007] In this respect, it is noted that incoming control signals normally are transmitted with a priority, e.g. a priority with which they are intended to be executed. However, some of the signals may also comprise priority setting indications, which for the purpose of this application shall be understood as indications relating to priority settings, e.g. the disablement or enablement of executions at one or more specific levels. [0008] Preferably, said control signals may comprise a time indication for said priority setting indications and wherein the at least one controllable unit may comprise means for establishing a corresponding timer function. [0009] Hereby, it is achieved that the selectivity of the system may be arranged in a dynamic manner and that the periods, for which levels may be disabled, may be defined in view of particular needs and requirements. [0010] According to a further advantageous embodiment, said means for registering said priority setting indications for storing a corresponding entry may comprise a priority and command level management table related to each of said at least one controllable node. [0011] Hereby, the system may be arranged in an advantageous manner. [0012] Advantageously, said priority and command level management table may comprise an evaluation row, wherein status is specified for each command level, based on an evaluation performed in accordance with a predetermined algorithm. [0013] Hereby, it is obtained that an evaluation result is readily presented and that when the controllable node receives a control signal requiring an actuation, a relatively simple comparison with the evaluation result in the evaluation row need only be performed in order to determine, what action has to be taken. [0014] Advantageously, said predetermined algorithm may involve the designation of disablement for a priority level, if at least one of the entries for said level contains a disablement indication. [0015] Hereby, a relatively uncomplicated manner of providing an evaluation is established, which furthermore results in a well-functioning system. [0016] According to a further advantageous embodiment, for said at least one controllable node a weight factor (k n ) may be allocated for each command level, on the basis of which a combined weight is determined for each entry, e.g. each row in a management table. [0017] Hereby, in accordance with a further aspect of the invention, a solution may be provided to the problems that may arise if a table is already filled with entries and an incoming signal, which comprises information relating to priority settings, i.e. priority settings that should be included in the table, is received. In this case, it may be determined that the entry with for example the lowest weight is removed. [0018] According to a still further advantageous embodiment, said at least one controllable node may be configured for deleting an entry if two or more of said entries are disabling at the same level, based on the combined weight for each entry. [0019] Thus, one of two entries that may for most purposes have the same effect, may be deleted, leaving room for a new entry that may have properties very unlike the entries already represented in the table, thus giving possibly new results to the evaluation. [0020] According to a further aspect of the invention, a control signal that is denied at the time of reception caused by the evaluated entries, may be stored for a predetermined time using a separate timer for a subsequent re-evaluation with the entries. [0021] Thus, the possibility that one of the entries in the table are near the end of the timer function may be used in such instances. [0022] The invention also relates to a method of operating a device such as for example an operator for a door, a gate, a window, blinds, shutters, a curtain, an awning or a light source, which device is associated with a controllable unit, said controllable unit being designed for receiving control signals from a plurality of nodes in a control system and activating said device in accordance with said control signals, whereby at least one of said control signals comprises priority indications relating to at least one of a plurality of levels, whereby said controllable unit registers and stores said priority setting indications as a corresponding entry when said control signal is received, and whereby said controllable unit performs an evaluation based said stored entry in the unit and acts in accordance with said evaluation. [0026] Hereby, it is achieved that priorities on a plurality of levels and possibly based on input from a plurality of sources may be handled in a logic and consistent manner. Further, it is achieved that a selective mask may be defined for the operation of the controllable units in the system. [0027] Preferably, said control signals may comprise a time indication for said priority setting indications, and whereby the at least one controllable unit establishes a corresponding timer function. [0028] Hereby, it is achieved that the selectivity of the system may be arranged in a dynamic manner and that the periods, for which levels may be disabled, may be defined in view of particular needs and requirements. Further, it is achieved that in case a node, which has transmitted a priority setting signal, for some reasons may not be able to alter or delete the specific setting, for example because the node has no power source, e.g. a flat battery, or has been removed so far from the system, that contact cannot be established, the specific priority setting will not remain for an unspecified time in the system, but will eventually be removed automatically, when the timer lapses. [0029] According to a further advantageous embodiment, said entries may be stored in a priority and command level management table related to said at least one controllable node. [0030] Hereby, the method may be arranged in an advantageous manner [0031] Advantageously, an evaluation may be performed in accordance with a predetermined algorithm for each level and the result may be specified for each command level in an evaluation row for said priority and command level management table. [0032] Hereby, it is obtained that an evaluation result is readily presented and that when the controllable node receives a control signal requiring an actuation, a relatively simple comparison with the evaluation result in the evaluation row need only be performed in order to determine, what action has to be taken. [0033] Preferably, said predetermined algorithm may involve the designation of disablement for a priority level, if at least one of the entries for said level contains a disablement indication. [0034] Hereby, a relatively uncomplicated manner of providing an evaluation is established, which furthermore results in a well-functioning system. [0035] According to a further advantageous embodiment, for said at least one controllable node a weight factor (k n ) may be allocated for each command level and a determination of a combined weight for each entry, e.g. each row in a management table, is performed. [0036] Hereby, in accordance with a further aspect of the invention, a solution may be provided to the problems that may arise if a table is already filled with entries and an incoming signal is received. In this case, it may be determined that the entry with for example the lowest weight is removed. [0037] Advantageously, an entry may be deleted, if two or more of said entries are disabling at the same level, based on the combined weight for each entry. [0038] Thus, one of two entries that may for most purposes have the same effect, may be deleted, leaving room for a new entry that may have properties very unlike the entries already represented in the table, thus giving possibly new results to the evaluation. [0039] According to a further advantageous embodiment, a control signal that is denied at the time of reception caused by the evaluated entries, may be stored for a predetermined time using a separate timer for a subsequent re-evaluation with the entries. [0040] Thus, the possibility that one of the entries in the table are near the end of the timer function may be used in such instances. BRIEF DESCRIPTION OF THE FIGURES [0041] The invention will be explained in further detail below with reference to the figures of which [0042] FIG. 1 shows in a schematic manner an example of a control system in accordance with the invention, [0043] FIG. 2 shows an example of a priority and command level management table in accordance with an embodiment of the invention, [0044] FIG. 3 illustrates an example of the processing of an incoming signal, [0045] FIG. 4 shows an example of a priority and command level management table in accordance with a further aspect of the invention. DETAILED DESCRIPTION OF THE INVENTION [0046] An example of a control system according to an embodiment of the invention, e.g. a home automation system or part thereof, is illustrated in FIG. 1 . Here, a building, a house or the like 1 is illustrated in a schematic manner, showing in detail only a part of the house or a room where a window 2 is located. The window 2 may be provided with a window actuator, operator or opener 4 , which may comprise a drive mechanism generally designated 6 and a controllable node 5 , e.g. a node comprising a radiofrequency receiver and control means. Further, the window 2 may be provided with an awning 3 , which is retractable as indicated, operated by means of an operator 8 . This operator 8 may comprise a drive engine generally designated 9 and a controllable node 10 , e.g. a node comprising a radiofrequency receiver and control means. [0047] The control system may also comprise one or more sensors such as e.g. a wind speed sensor 12 , a sunlight sensor 16 and a rain sensor 19 . Such sensors may as indicated comprise a sensor part, e.g. an anemometer 13 and a photometer 17 , respectively, and a transmitter part, e.g. 14 and 18 , respectively, which transmitter parts may e.g. comprise RF-means or may rely on wired transmission. The rain sensor 19 may be integrated with the window 2 , but will also comprise a sensor part and a transmitter part (not illustrated). Further sensors or controllers may be provided, also inside the room, for example in the form of a temperature sensor etc. [0048] Further, the control system may comprise one or more remote controls 20 and 22 as shown for operating the controllable devices, e.g. the window opener 4 and the awning 3 . These remote controls may be similar, e.g. comprise similar properties, but the may also differ, e.g. have different properties as regards e.g. priority. One, e.g. the remote control 20 may for example be a master control while another, e.g. the remote control 22 may be a slave remote control. [0049] These remote controls 20 and 22 and the sensors 12 , 16 and 19 may all transmit control signals to the controllable units, e.g. the controllable nodes 5 and 10 , associated with the window 2 and the awning 3 , respectively. It will be understood that the terms “control signals” in this respect comprise any signal transmitted from a node such as a sensor or a remote control to a controllable unit, including signals representing measured values etc., and that the controllable unit may or may not react upon such a signal, e.g. in accordance with certain predefined or established rules. [0050] As explained above, it will in most cases be necessary to prioritize the control signals. For example, it may be necessary to arrange that a signal transmitted from a wind sensor to the controllable unit associated with an awning has a higher priority than a signal sent from a remote control, e.g. in order to achieve that the awning is maintained in a retracted position when the force of the wind is above a predetermined level. [0051] In order to manage such priorities, signals from the sensor and control nodes may be provided with priority setting indications at a number of levels, and when these signals are received at the controllable nodes, they are registered and stored in the form of an entry in a table, and an evaluation is performed on the basis of the stored information in the table. On the basis of this evaluation the device associated with the controllable unit is operated, e.g. activated, stalled, stopped, reversed, etc. when a control signal requesting e.g. an actuation is received at the node. [0052] This table is indicated by the symbol 30 shown in FIG. 1 associated with each of the controllable nodes, e.g. the nodes 5 and 10 in this example. [0053] The details of such a table will be further explained with reference to FIG. 2 , which shows an example of such a management table 30 for a controllable node or device in a control system. [0054] The priority levels may in accordance with usual practice be arranged in a decreasing way, for example in the following order: Human security, product or environment protection, user manual operation, automatic comfort control. A number of levels may be defined, for example eight levels as shown at 31 in FIG. 2 , ranging from the highest level 0 to the lowest level 7 , and of these levels the four lowest may be designated to comfort automatic control levels, levels 3 and 2 may be designated to user manual control, while levels 1 and 0 thus are designated for product or environment protection and human security, respectively. [0055] When a signal is received from a node, the content of this signal that relates to priority or priorities on certain command levels leads to the storing of an entry in a management table as shown in FIG. 2 . Here, each row e.g. 32 , 33 , 34 corresponds to a signal transmitted from a node to the specific controllable node, and it will be understood that each controllable node comprises such a management table. For each command the table may comprise a priority, e.g. “enable” or “disable” that will lead to a corresponding setting in the table. If the received signal does not specify “enable” or “disable” for a priority level, the evaluation will not be influenced by the signal on this level. Thus, the entry for such a signal at such a level may be e.g. “enable”, if the evaluation rule specifies that the result should be “enable”, unless at least one “disable” is present. [0056] Further, the control signal may also indicate a period of time, in which the entry must be stored in the table, for example 15 minutes from receipt of the command. Thus, the table will also contain a column 35 indicating a timer operation, e.g. indicating the total time period for the entry in question or the remaining time for the entry. It is obvious that the controllable nodes comprise timer means for managing the table 30 . [0057] Further, it is noted that if a command signal is received, e.g. a signal requesting an actuation that cannot be executed because the specific level is locked, when the signal is received, the command signal may be saved for a specific period, e.g. 10 minutes, facilitated by a separate timer. The signal may be handled again at the lapse of the 10 minutes period, but preferably it is handled continuously during the period, e.g. in order to have the command executed as fast as a blocking has been removed from the table. If the priority level is still locked at the lapse of the period, the command signal may then be discarded. [0058] When the table is established and when a new command comprising priority indications is received, an entry is made in the table, the table is evaluated and the result is registered in the evaluation row 38 . Different rules and algorithms may be used for performing the evaluation. For example as shown in FIG. 2 , for each level it is indicated that a command level is disabled when it contains at least one “disable” priority. Another manner of evaluating the table could for instance be to evaluate based on a majority. It is obvious that the manner of evaluating may differ from node to node, for example in dependence on the type of device that is associated with the controllable node. [0059] An incoming new command signal that contains a command on a level, that is disabled, cannot be executed, whereas a command on a level that is not disabled can be executed. [0060] Further, it is noted that if the level “ 0 ”, i.e. Human Security is disabled, it may be arranged that all lower levels will also be disabled in order to ensure the human protection. [0061] As mentioned, the evaluation is performed each time a new command signal comprising priority setting indications is received, but when a command is removed from the table because the time period has lapsed, the evaluation may also be re-evaluated. Further, it will be understood that the table may be re-evaluated with regular intervals. [0062] The manner in which an incoming signal is handled may be exemplified with reference to FIG. 3 . Here, an incoming control signal 50 may first be examined 51 for any enclosed information regarding prioritizing. If the signal contains such information, a corresponding entry at 52 in the management table is performed. If it does not contain such information, it is examined at 53 , whether the signal contains any information that will require an actuation. As shown, this may also be performed after the signal has initiated an entry in the management table. If an actuation is requested, it is examined at 54 whether this actuation is enabled or disabled. If it is not disabled, the actuation is performed at 55 . If it is disabled, the signal may possibly be pooled for a delay period as shown at 55 for later evaluation in view of the content of the management table. Otherwise the signal is discarded 56 . [0063] In the example described above, the signal is examined for any information regarding priority setting(s) before it is examined whether it also request an actuation. However, it may normally be preferable to examine the signal first for a request for an actuation and thereafter for priority setting(s). In this manner, it is avoided that the specific signal may set a priority that may preclude the actuation it is requesting itself. [0064] Each time a control signal is received at the controllable node, the table 30 is updated, e.g. if a timer function has lapsed, the entry is deleted from the table, before the control signal is evaluated in regard to the content of the table. [0065] It will be understood that the table for practical reasons will be limited as regards the number of entries. If a control signal is received that has a content requiring an entry to be made when the table is full, different solutions are possible. The simplest solution is to reject the control signal. [0066] However, other manners of handling such a situation are possible. For example, it may be decided that the entry with the smallest remaining timer value may be excluded etc. [0067] A still further method is illustrated in FIG. 4 . Here, a management table 30 corresponding to the one shown in FIG. 2 is illustrated. However, this table comprises a row 39 with weight factors k n that as shown may be for example 1, 2, 4, 8, 16, 32, 64 and 128 for the respective levels, i.e. 2 n , but in the reverse order. These weighing factors may be combined with the priority identifications in the respective entries, e.g. by multiplying the factors with the “disable”-entries and summing, which results in the column 40 showing the combined weight of each entry. [0068] If a signal has been received that will lead to an entry, and the table is full, it may be decided that if two entries are locking at the same higher level, e.g. as shown with the entry 32 and 33 that are both locking at level 2 , the weight factor may be taken into regard. The entry 32 has the lowest combined weight, and therefore this entry is removed from the table and the new entry is introduced instead. [0069] The shown weight factors are only examples of, what may be used, but in general it preferable that the factors are increased in such a manner that one entry that has only one “disable” at e.g. level m will achieve a higher combined weight than another entry that has “disable” at all levels lower than m. In this manner it is achieved that an entry with the highest “disable”-entry always will be maintained. This is achieved with the rule “2 n , but in the reverse order”. [0070] It will be understood that the invention is not limited to the particular examples described above and illustrated in the drawings but may be modified in numerous manners and used in a variety of applications within the scope of the invention as specified in the claims.

System and method for controlling at least one device such as for example an operator for a door, a gate, a window, blinds, shutters, a curtain, an awning or a light source including a controllable unit associated with the at least one device and a plurality of nodes for transmitting control signals to the at least one controllable unit. At least one of the control signals includes priority setting indications relating to at least one of a plurality of levels. At least one controllable unit comprises means for registering the priority indications and for storing a corresponding entry relating to the plurality of command levels. Further, the controllable unit includes means for performing an evaluation based on the stored entries.

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The field of the invention is portable high intensity light sources of a type which will illuminate a planar surface with a low angle of illumination that skims along the planar surface. Such a device is particularly useful for locating very small hard to find items. [0003] 2. Description of the Prior Art [0004] Flashlights and portable lighting devices are well known in the prior art. Such devices sometimes are modified to suit a specific purpose or are adjustable to suit a variety of purposes. Portable flashlights are often classified as either “spot” lights or “flood” lights depending on whether the beam is focused into a narrow beam or defocused to cover a wider area. Flood lights are sometimes referred to as area lights, especially when there is some attempt to shape the beam to light a specific area. In some cases lights contain both a spot and flood light or have a means for adjusting the spread of the beam to achieve either effect or a variant in between. [0005] Typical uses for these lights are for seeing in places where the existing ambient light does not fall. This may include looking under stairs, deep in a closet, deep in a cabinet, under a couch, under a workbench, or for looking around a backyard at night. Flashlights are also kept on hand for emergency purposes such as a power failure or for signaling someone in the dark to alert them. [0006] To date, the previous art has not described a flashlight designed and optimized for highlighting small hard to see items, such as broken glass, dropped contact lenses or the backs of earrings. The instant invention describes a light specifically designed to provide a highly intense but uniform beam of light designed for highlighting small items on a floor or other flat surface. [0007] For many years the concept of illuminating an object with a low grazing angle has been used in microscopy and industrial machine vision applications for the purpose highlighting defects or particles on relatively flat surfaces. This is sometimes referred to as “dark field illumination.” The fundamental concept is to use lighting at an angle to the surface such that anything that sits on or protrudes from the surface will scatter light up to an eye, a detector or a camera. Light that is reflected directly from the surface itself will never reach the eye, detector or camera. For noisy backgrounds or difficult to see objects, this concepte can be taken to extremes such that the illumination source is at a very low grazing angle with respect to the surface. This can form an even higher contrast between surface and any objects on the surface so that they can easily be detected. The low grazing angle minimizes any reflection from the flat surface while maximizing the reflection from the objects on the surface. In cases where the illumination is coming from a single direction, any objects on the surface will also cast a long shadow behind the object thus making them easier to find. Grazing angle is defined as the angle between a light beam and a surface (i.e. 90 degrees minus the angle of incidence). [0008] Systems have been described to locate small or submerged items with light or radar in marine systems using low grazing angle incident radiation. [0009] U.S. Patent Application 20070035624 by Lubard, et al, discloses a system and for detection of objects that are submerged, or partially submerged (e. g. floating), relative to a water surface. One aspect of the invention is the use of Light Detection and Ranging (LIDAR) emitting nearly horizontal pulses to illuminate small exposed objects at tens of kilometers, detecting successive reflected portions and images with a streak-tube subsystem. The prior art further describes an experimental deployment shown by Anderson, Howarth and Mooradian (“Grazing Angle LIDAR for Detection of Shallow Submerged Objects”, Proc. International Conference on Lasers, 1978) for shallow angle marine observation at short range. [0010] U.S. Patent Application 20060273946 to Krikorian et al, discloses a radar system where the target is illuminated from a plurality of locations to generate images at many aspect angles. The radar is positioned at a low grazing angle with respect to the target for generating a shadow of the target on the flat or sloping terrain for each aspect angle of the plurality of aspect angles. [0011] U.S. Pat. No. 6,836,285 to Lubard, et al, discloses a LIDAR system or other means at an elevated position emit thin fan-beam light pulses at a shallow angle, and detect reflected portions of the pulses at a like angle in marine systems. Preferably the shallow angle is in a range of approximately one to fifteen degrees, more preferably approximately two to ten degrees, ideally roughly five degrees. [0012] U.S. Pat. No. 4,926,299 by Warren E. Gilson describes a “portable flashlight” that provides a reflector which provides non-glare illumination of a relatively small rectangular area such as along a sidewalk or stair tread. The primary object of this is to provide a uniformly lit area generally without intense glare. The flashlight also contains a mode that more focused high intensity spot light. While a light of this nature may conceivably be used in a low grazing angle situation, either mode will be sub-optimal for the purpose of highlighting small objects on a flat surface. [0013] In the area mode, the rectangular area illuminated is described as being “small and generally without intense glare.” The area mode is designed to project a rectangular shaped beam in an axis perpendicular to the optical axis of the beam (reference FIG. 6 in U.S. Pat. No. 4,926,299). In order to be strong enough to highlight small particles or objects, the beam would need to be of high intensity and focused in a manner that would provide uniform light on the floor when projected at a low grazing angle more along an axis directed toward to the floor. [0014] In the spotlight mode, the flashlight may have enough intensity to highlight small particles if held at an appropriate angle to the floor. Unfortunately there will need to be significant manipulation by the user to get the angle correct. Additionally, the narrow nature of a spotlight beam will require the user to perform much more manual “scanning” of the surface to view a wide area. [0015] U.S. Pat. No. 4,605,994 to Rudolf Krieg describes a “flash lamp” with essentially uniform illumination respective of spot and flood fields. This flashlight is interesting in that it can be adjusted to achieve varying intensities and beam spreads with highly uniform results perpendicular to the primary optical axis. Again, by holding this flashlight close to the floor and manipulating it, it may effectively highlight small particles or objects. Unfortunately this lamp is optimized to provide a circularly uniform pattern perpendicular to the primary axis. The overall shape of the beam will be inefficient when projected at angles nearly parallel to the floor. The end result will be a very elongated oval brightly lit area across the floor. This can be useful, but tedious in that it will require significant manual scanning to inspect a wide area for the purpose of locating small particles. [0016] U.S. Pat. No. 4,414,612 describes a flashlight that not only adjusts the beam width but also the orientation of the head. This flashlight has a flat bottom surface such that it could be placed flat on a floor. With the adjustable head orientation it may be possible to find a position that works better that a normal flashlight for low grazing angle illumination, albeit not optimized. Where this light falls short is in the shaping of the beam for the application. Like most flashlights this contains a parabolic reflector that is circularly symmetric (i.e. it provides a relatively circular shaped beam perpendicular to the primary optical axis). The pattern it projects while grazing across a flat surface will not be efficiently optimized for high intensity light across a wide area of the floor (again, a very elongated illumination pattern). [0017] U.S. Pat. No. 2,889,450 describes a casing for a lighting device that has edges of varying angles such that the beam can be directed in one of several directions when set on a flat surface. One of these directions is parallel to the floor. Having the beam perfectly parallel to the floor is not effective as most of the emitted light will actually not strike the floor. The light needs to be near parallel directed at a slight angle toward the floor. The other positions available on this lamp direct light away from the floor and are not suitable for the purpose of locating small items. This light also suffers from the same deficiency as the previous lights in that the projected beam shape will be circular in a plane perpendicular to the optical axis. [0018] There is a need for a portable illuminator which will optimally illuminate small items on a planar surface. [0019] There is a need for an illuminator capable of resting flat on a planar surface and providing a high intensity, uniform illumination of the surface in an area extending from immediately adjacent to the light and for a further distance from the light, wherein said illumination is characterized by a low grazing angle that will illuminate small items on the surface. The light will also cast a long shadow behind any object (on the side opposite the light source). [0020] There is a need for a portable illuminator capable of resting flat on a planar surface and providing a high intensity, uniform illumination of the surface in an area extending from immediately adjacent to the light and for a further distance from the light, wherein said illumination is characterized by a grazing angle less than 10 degrees. [0021] There is a need for a portable illuminator capable of resting flat on a planar surface and providing a high intensity, uniform illumination of the surface in an area extending from immediately adjacent to the light and for a further distance from the light, wherein said illumination is characterized by a grazing angle less than 6 degrees. SUMMARY OF THE INVENTION [0022] One preferred embodiment of the invention is a portable illuminator which is well suited to illuminate a floor or other planar surface for the purpose of locating small, hard to see items, including but not limited to finding glass, small shards or debris, contact lenses, earring backs, tiny screws, and the like. It does this by producing a very low grazing angle illumination that skims across the planar surface. For the purposes of this application grazing angle is defined as the angle between a light beam and a surface (i.e. 90 degrees minus the angle of incidence). [0023] The instant invention builds on the concept of dark field illumination which has been used for microscopy and industrial machine vision applications to highlight defects on flat surfaces. The fundamental concept is to use lighting at an angle to the surface such that anything that sits on or protrudes from the surface will scatter light upwards to an eye, a detector or a camera. Light that is reflected directly from the surface will never reach the eye, detector or camera. [0024] For noisy backgrounds or difficult to see objects, the concept of dark field illumination can be taken to extremes such that the illumination source is at a very low grazing angle with respect to the surface. This can form an even higher contrast between surface and any objects on the surface so that they can easily be detected. [0025] With a properly designed portable illuminator, a low grazing angle dark field concept can be applied for the simple application of locating broken glass, dirt, or other small objects on a floor or flat surface. If a person is looking down onto a floor or flat surface that is illuminated with low grazing angle illumination, the person will observe the same affect light scattering effect that a camera or detector would. The light scattering from any object sitting on the surface will be much brighter than any light reflected from the surface. Furthermore, if the illumination is coming from only one direction, a long shadow will be cast immediately behind any object in the path of the light. This long shadow provides further contrast of normally hard to see particles on a surface. [0026] A portable illuminator according to the invention comprises: a) a body capable of resting flat on a planar surface, b) at least one high intensity light source mounted in the body, c) at least one light shaping means mounted in the body, capable of providing high intensity, uniform illumination of the surface in an area extending from immediately adjacent to the illuminator and for a further distance from the illumination, wherein said illumination is characterized by a low grazing angle, and d) whereby said high intensity light is focused at an angle nearly parallel to the surface. [0031] Several embodiments of the light shaping means comprise a reflector, a reflector in series with a cylindrical lens, and a reflector in series with a fresnel lens. [0032] A low grazing angle may be less than 30 degrees, preferably less than 10 degrees and more preferably less than 6 degrees. [0033] A high intensity light produces 700-5000 lux and more preferably 800-5000 lux at a distance of up to 5 feet from the source and preferably at least 10 feet. [0034] The light is used by putting the light flat on the surface and allowing the light to illuminate the surface, and look for small articles on the surface. The light may be systematically moved from place to place until the entire surface is inspected. [0035] It is an object of the invention to supply a portable illuminator which will optimally illuminate small items on a planar surface. [0036] It is a further object of the invention to supply a portable illuminator capable of resting flat on a planar surface and providing a high intensity, uniform illumination of the surface in an area extending from immediately adjacent to the light and for a further distance from the light, wherein said illumination is characterized by a low grazing angle that will illuminate small items on the surface. The light will also cast a long shadow behind any object (on the side opposite the light source). [0037] It is a still further object of the invention to supply a portable illuminator capable of resting flat on a planar surface and providing a high intensity, uniform illumination of the surface in an area extending from immediately adjacent to the light and for a further distance from the light, wherein said illumination is characterized by a grazing angle less than 10 degrees. BRIEF DESCRIPTION OF THE DRAWINGS [0038] These and other features, aspects and advantages of the present invention will become better understood with regard to the following description, appended claims and accompanying drawings, where: [0039] FIG. 1 a is a view of a typical prior art flashlight. [0040] FIG. 1 b is a view of the resulting beam pattern from the prior art flashlight. [0041] FIG. 2 a is a side view of one preferred embodiment of the invention. [0042] FIG. 2 b is a top view of the same embodiment. [0043] FIG. 2 c is a side view of an embodiment with two light producing structures. [0044] FIG. 2 d is a top view of the embodiment in 2 c. [0045] FIG. 3 shows top, side, and front views of the light producing structure comprising a reflector and a cylindrical lens. [0046] FIG. 4 shows top, side, and front views of the light producing structure comprising a reflector and a fresnel lens. [0047] FIG. 5 shows top, side, and front views of the light producing structure comprising a reflector and a piano lens. DESCRIPTION OF THE PREFERRED EMBODIMENTS [0048] One preferred embodiment of the invention is a portable illuminator which is well suited to illuminate a floor or other planar surface for the purpose of locating small, hard to see items, including but not limited to finding glass, small shards or debris, contact lenses, earring backs, tiny screws, and the like. It does this by producing a very low grazing angle illumination that skims across the planar surface. For the purposes of this Application, grazing angle is the angle between a light beam and a surface (i.e. 90 degrees minus the angle of incidence). [0049] With a properly designed portable light, a low grazing angle can be applied for the simple application of locating broken glass, dirt, or other small objects on a floor or flat surface. If a person is looking down onto a floor or flat surface that is illuminated with uniform low grazing angle light will observe that the light reflected from small objects will be much brighter than the light reflected from the surface. Furthermore, if the illumination is coming from only one direction, a long shadow will be cast immediately behind any object in the path of the light. This long shadow provides further contrast of normally hard to see particles on a surface and sets off the small object. [0050] Moving to the Figures, FIG. 1 shows a prior art flashlight. Note that it is not configured to cast a uniform light on a surface below such as the floor. It comprises a body 10 , a light bulb 12 , within the body, a parabolic reflector 14 , cover 16 and an optical axis 18 . It produces a beam pattern 19 , which is characterized by relatively dark and relatively light spots. [0051] Several disadvantages of prior art flashlights with respect to the task of locating small items on a surface are noted: (1) General purpose flashlights are designed to emit a beam of light that is somewhat divergent in all axis's perpendicular to the primary axis of the beam (i.e. over a distance the spot tends to get larger to illuminate lager areas) (2) The beam pattern tends to be somewhat symmetric around the optical axis, the beam profile is not optimized to focus most of the light so that it skims across a surface (3) Since the flashlight does not sit flat on the surface, the user needs to bend over and provide excess manipulation to ensure that a high intensity portion of the beam is skimming across the floor (4) Most flashlights have significant hot and cold spots on the illuminated area (i.e. there is a great deal of fluctuation of the beam brightness across the field being illuminated). (5) Flashlights that have enough intensity for this application work typically have larger round reflectors (3″-6″) making it difficult to get the brightest spot of the source (in the center) very close to the surface. [0057] FIGS. 2A and 2B show the side and top views respectively of the outside of the body 26 of a preferred portable surface skimming illuminator according to the invention. Notice that in FIG. 2A , the illuminator body sits flat on the floor and in the vertical the beam profile 20 is focused to skim across the floor at a small grazing angle. In the horizontal, the beam 22 and 24 is divergent to illuminate a wider area than the illuminator itself. [0058] FIGS. 2 c and 2 d are similar to 2 a and 2 b , except that there is a much wider divergent beam between rays 22 and 24 on FIG. 2 d , due to having 2 light producing structures 27 and 28 . [0059] FIG. 3 shows the side, top, and front views of the light producing structure of one preferred embodiment of the illuminator. The illuminator comprises: a body 30 capable of resting flat on a planar surface (shown in the drawing is the front part of the whole body 26 shown in FIGS. 2A and 2B ), a high intensity light 32 source mounted in the body, and a light shaping means 34 mounted in the body, capable of providing high intensity, uniform illumination of the surface in an area extending from immediately adjacent to the light and for a further distance from the light. The illumination is characterized by a low grazing angle to the surface. In this case the light shaping means comprises an internal reflector 36 , and a cylindrical lens 38 . [0060] A low grazing angle is preferably less than 30 degrees more preferably less than 10 degrees, and most preferably between to 6 degrees and 0 degrees (inclusive), where 0 is a beam of light parallel to the floor. [0061] High intensity uniform lighting refers to the brightness of the light being at least 700 lux on the floor at a distance from less than one foot and to at least 5 feet from the source. More preferably the brightness should be greater than 2500 lux and most preferably greater than 5000 lux. It is most preferable to cast the beam on the floor at distances up to 5 feet, most preferably at least 10 feet. [0062] The illuminator body is preferably made by injection molding plastic. The construction is conventional and will be well known to those skilled in the art. Similarly, the optics of the lens and reflector is conventional for a particular size of illuminator and will be calculated by ordinary physics. [0063] The light source can be of any type. Some examples include incandescent, tungsten, krypton, xenon, LED's, LED arrays, scanning lasers, and equivalents thereto. An important aspect here is that the light source is preferably within about zero to six inches of the surface such that can be positioned close enough to the surface to form a low grazing angle and is shaped or focused for uniform lighting that skims across the surface. There can also be multiple light sources within one device to provide a wider area of coverage. [0064] FIG. 4 shows an alternative embodiment, with the shaping means comprising a reflector and a fresnel lens 42 in place of the cylindrical lens 38 in FIG. 3 , and which is otherwise identical to FIG. 3 . [0065] FIG. 5 shows another alternative embodiment, with the shaping means comprising a reflector and a piano lens 42 in place of the cylindrical lens 38 in FIG. 3 , and the fresnel lens 42 in FIG. 4 , and which is otherwise identical to FIGS. 3 and 4 . [0066] Although the present invention has been described in considerable detail with reference to certain preferred versions thereof, other versions are possible. Therefore the spirit and scope of the appended claims should not be limited to the preferred versions herein.

This invention describes a light source that is designed to illuminate a floor or other flat work surface for the purpose of locating small hard to see objects. This can be for the purpose of cleaning or simply locating a small valuable object. The light source is fashioned such that it provides a very low grazing angle of illumination that it skims across a surface. Small objects or particles are visible as being brighter than the surroundings and set off by a long shadow on the side of the particle away from the light.

BACKGROUND OF THE INVENTION [0001] 1. Technical Field of the Invention [0002] The present invention relates generally to mounting of heatsinks and the like to semiconductor devices, motherboards, and the like. More specifically, it relates to dampening measures for such mounting. [0003] 2. Background Art [0004] [0004]FIG. 1 illustrates a known technique for mounting a heatsink 10 to a chip assembly on a motherboard 12 . The chip assembly may, for example, include a microelectronic die 14 (such as a flip-chip die) connected by bumps 16 to a card 18 which is connected by solder balls 20 to the motherboard. Typically, thermal grease 22 is used to provide good thermal mating of the die and the heatsink. [0005] In applications where the heatsink is quite heavy, springs 24 are used to support the weight of the heatsink, taking the weight off of the die and card. The heatsink is attached, and the springs are drawn into compression, by bolts 26 and nuts 28 . [0006] While the springs may do an adequate job of supporting the heatsink under stationary conditions, they have been found inadequate in applications where the assembly is subject to significant shock or vibration. [0007] [0007]FIG. 2 illustrates one problem that exists in this prior art. When subjected to shock or vibration, the heatsink travels downward, further compressing the spring. If the shock or vibration is severe enough in amplitude or duration, the heatsink may eventually impact the die with sufficient force to break the die or at least some of the interconnects. In the prior art, the solution has been to use stiffer springs in such applications, to reduce the tendency of the heatsink to impact the die. Unfortunately, this introduces another problem. [0008] [0008]FIG. 3 illustrates what can happen if the springs are too strong and/or are drawn down with excessive preload and/or if the heatsink is subjected to shock or vibration with a significant upward component. In severe cases, the motherboard itself may fracture or suffer failure of its electrical traces or other devices. Even if the springs are not the problem, the motherboard may fail on its own, due to vibration or oscillation. [0009] It is desirable to dampen the movement of the heatsink and motherboard relative to each other and relative to the other components of the assembly. BRIEF DESCRIPTION OF THE DRAWINGS [0010] The invention will be understood more fully from the detailed description given below and from the accompanying drawings of embodiments of the invention which, however, should not be taken to limit the invention to the specific embodiments described, but are for explanation and understanding only. [0011] [0011]FIG. 1 shows, in cross-section, a heatsink attach system according to the prior art, in which springs are used to support the heatsink. [0012] [0012]FIG. 2 shows, in cross-section, the heatsink breaking the semiconductor die under shock or vibration. [0013] [0013]FIG. 3 shows, in cross-section, the motherboard fracturing under shock or vibration or excessive spring preload. [0014] [0014]FIG. 4 shows, in cross-section, one embodiment of the invention, in which shock absorbers are added to the assembly to dampen shock and vibration. [0015] [0015]FIG. 5 shows, in cross-section, another embodiment in which the springs and shock absorbers are coaxially mounted. [0016] [0016]FIG. 6 shows, in cross-section, another embodiment in which the springs are under tension rather than compression, obviating the need for hold-down bolts. [0017] [0017]FIG. 7 shows, in cross-section, another embodiment in which the springs are integrated within the shock absorbers. [0018] [0018]FIG. 8 shows, in cross-section, one embodiment of a shock absorber which is adapted for being affixed to the heatsink and motherboard. [0019] [0019]FIG. 9 shows, in cross-section, another embodiment of a shock absorber. [0020] [0020]FIG. 10 shows, in cross-section, another embodiment of a shock absorber, with an integral spring. [0021] [0021]FIG. 11 shows, in top view, one embodiment of a placement of the shock absorbers. [0022] [0022]FIGS. 12 and 13 show, in top view, one embodiment of an attachment mechanism for the shock absorber. DETAILED DESCRIPTION [0023] Embodiments of the invention are shown in this patent in an application involving a flip-chip die assembly, but the skilled reader will appreciate that the invention is not limited to such applications. [0024] [0024]FIG. 4 illustrates one embodiment of the invention, in which the shock absorbers 30 are mounted in parallel with the springs, bolts, or other heatsink supporting means. In some such embodiments, it may be desirable to place the shock absorbers as near the springs and hold-down bolts as possible. In others, it may be desirable to place the shock absorbers elsewhere. For example, in some applications it may be desirable to place the shock absorbers as near the ends of the heatsink as practicable, to maximize their effect in preventing the heatsink from levering about a fulcrum (the die). [0025] [0025]FIG. 5 illustrates another embodiment of the invention, in which the shock absorbers are mounted serially, or coaxially, with the springs. In some such embodiments, the hold-down bolts may be omitted, and the shock absorbers may perform the hold-down function. [0026] [0026]FIG. 6 illustrates yet another embodiment, in which the springs perform the hold-down function. In some such embodiments, the springs may under tension rather than compression. In such embodiments, the die will bear not only the weight of the heatsink, but also the tension of the springs. Thus, this embodiment may not be suitable for all applications. The reader will appreciate that the springs could readily be mounted coaxially with the shock absorbers. [0027] [0027]FIG. 7 illustrates yet another embodiment, utilizing shock absorbers which have integral springs. In various such embodiments, the springs may be under compression or tension. If under tension, the springs will, of course, need to be affixed to the shock absorbers rather than merely disposed within them in a free-floating manner. [0028] [0028]FIG. 8 illustrates details of one exemplary shock absorber, such as those shown in FIG. 4. The shock absorber includes a cylinder component 40 and a piston component 42 . The piston moves axially within the cylinder. The piston component 42 of the shock absorber includes an operative piston segment 44 sized appropriately to fit within an operative cylinder segment 46 of the cylinder component 40 . In some embodiments, the dampening orifice may comprise a gap between the walls of the cylinder and the piston. In other embodiments, the dampening orifice may comprise one or more holes (not shown) through the piston or cylinder. In some embodiments, it may be desirable to employ pneumatic dampening, while in others it may be desirable to utilize hydraulic dampening. The choice of dampening mechanism, the selection of orifice sizes, fluid viscosities, and such are application dependent, and within the abilities of an ordinary skilled workman. In some embodiments, it may even be acceptable to use a frictional dampening mechanism, such as one in which two or more parts rub against each other to dampen motion in the direction of their overall assembly length. In some embodiments, it may be suitable to use a shock absorber with no moving parts, such as a rubber or plastic foam having a suitable “memory speed” and “memory pressure”. The reader should appreciate that the various drawings, while illustrating piston and cylinder style shock absorbers, may also be interpreted as teaching the use of such foam or frictional dampening mechanisms. [0029] [0029]FIG. 9 illustrates another embodiment of the shock absorber, in which the end 68 of the cylinder component and the end 70 of the piston component are threaded. In this embodiment, they may be retained to the heatsink and the motherboard by threaded nuts (not shown). In some applications, it may be suitable to thread the piston or cylinder component directly to the heatsink. [0030] Other retention mechanisms will be appreciated by the reader as being within the grasp of those of ordinary skill in this field. For example, the piston and/or cylinder components might include integral bolt heads. Or, they may be welded, glued, or otherwise affixed. FIG. 5 also illustrates that it is not necessarily required that the piston and the cylinder be affixed with the same mechanism. [0031] [0031]FIG. 9 also illustrates what was mentioned previously with reference to FIG. 5, in that in some embodiments the shock absorber itself may provide the hold-down functionality that was done by separate bolts in the prior art and in other embodiments. In this embodiment, the piston and cylinder will, when installed, be topped out against one another at the inner lip of the end of the cylinder and the bottom edge of the piston, denoted as location 72 . This configuration may be utilized in drawing the heatsink support spring into preload, as shown in FIG. 5. [0032] [0032]FIG. 10 illustrates another embodiment of the shock absorber, such as that used in FIG. 7. In this embodiment, the shock absorber includes the spring 74 within the cylinder chamber. In applications where the spring is to be under tension, the spring is affixed to the cylinder portion 40 and the piston portion 42 of the shock absorber. [0033] In some applications, it may be desirable to utilize both the main support springs external to the shock absorber, and also the internal shock absorber springs 74 . [0034] [0034]FIG. 11 illustrates that, in some embodiments, it is not necessarily desirable that the shock absorbers and the hold-down bolts be located near each other. FIG. 11 illustrates one such embodiment, in which the hold-down bolts or other such mechanism, denoted by the circles labeled B, are located at the corners of the heatsink, while the shock absorbers, denoted by the circles labeled S, are located in the middle of each side. The small squares stylistically represent multiple fins on the heatsink. The motherboard 12 is shown, and the outline of the chip 14 is shown as a dotted line. [0035] [0035]FIGS. 12 and 13 illustrate one embodiment of an attachment mechanism for the shock absorbers, such as utilized in the applications shown in FIGS. 4, 6, and 7 . Please refer to FIGS. 8, 12, and 13 . The piston component includes an end cap 48 , a middle cap 50 , and a segment 52 having a diameter and length suitable for engaging a keyed slot 54 on the motherboard. The keyed slot includes a portion 56 sized sufficiently large to pass the end cap 48 . The piston is inserted through the motherboard until the segment 52 is aligned with the motherboard, then the piston is slid into the keyhole, where the end cap and middle cap will mechanically grip the two sides of the motherboard, preventing axial movement of the piston relative to the motherboard, and the segment 52 will prevent lateral movement. The piston may be retained in this position by any suitable mechanism (not shown). For example, the end portion of the slot could be sized slightly larger than the rest of the slot, so the piston would be retained in a snap fit. [0036] Similarly, in this embodiment, the cylinder portion 40 includes an end cap 58 and a middle cap 60 with a segment 62 between them, and the cylinder portion may be fitted to the heatsink in the same manner as the piston is fitted to the motherboard. The segment 64 of the piston component between the piston and the middle cap, and the segment 66 of the cylinder component between the cylinder and the middle cap, may be of any suitable length and diameter. [0037] The reader will appreciate that the positions of the piston and cylinder may be reversed, in some embodiments. The reader will further appreciate that the cylinder end may be open, to permit removal of the piston component, or it may be substantially closed, to prevent removal of the piston component. [0038] The reader will appreciate that the invention may readily be used in applications where the microelectronic die is coupled directly to the motherboard, or those employing an interposer, or those in which the die is socketed, and so forth. [0039] The skilled reader will appreciate that the utilization of this invention may permit the removal or reduction of board stiffeners on the motherboard, the use of larger form factor and higher mass heat sinks, and/or thinner motherboards. The skilled reader will further appreciate that the utilization of this invention may also enable the heatsink attachment to withstand more extreme usage environments that result in higher shock or vibration. [0040] The reader will appreciate that the term “motherboard” should not be interpreted as meaning only the primary or main board of an electronic system, but that this invention may be utilized in conjunction with a wide variety of boards and the like. The skilled reader will also appreciate that the term “shock absorber” refers to any suitable dampening mechanism, and is not limited to the coaxial piston and cylinder embodiment illustrated above by way of simplicity and teaching. [0041] Reference in the specification to “an embodiment,” “one embodiment,” “some embodiments,” or “other embodiments” means that a particular feature, structure, or characteristic described in connection with the embodiments is included in at least some embodiments, but not necessarily all embodiments, of the invention. The various appearances “an embodiment,” “one embodiment,” or “some embodiments” are not necessarily all referring to the same embodiments. [0042] If the specification states a component, feature, structure, or characteristic “may”, “might”, or “could” be included, that particular component, feature, structure, or characteristic is not required to be included. If the specification or claim refers to “a” or “an” element, that does not mean there is only one of the element. If the specification or claims refer to “an additional” element, that does not preclude there being more than one of the additional element. [0043] Those skilled in the art having the benefit of this disclosure will appreciate that many other variations from the foregoing description and drawings may be made within the scope of the present invention. Indeed, the invention is not limited to the details described above. Rather, it is the following claims including any amendments thereto that define the scope of the invention.

Shock absorbers or other dampening mechanisms are added to an assembly including a heatsink, a semiconductor device, and a board, to reduce shock and/or vibration induced relative motion between the heatsink and the board.

This application is a continuation-in-part of applicant's U.S. patent application Ser. No. 08/279,487 filed Jul. 22, 1994, now U.S. Pat. No. 5,526,179. BACKGROUND 1. Field of the Invention This invention relates to a new and improved light glare reducing device and more specifically a glare control device for illuminating vehicle pathways and other illumination. BACKGROUND 2. Description of Prior Art Headlight glare is a persistent safety hazard in night driving and over the years many systems have been proposed to suppress headlight glare. In general, the prior art systems fall into two broad categories. In the first, polarizing filters placed over the headlights polarize the emitted light at a 45 degree axis and a similar polarizing filter is used as a visor through which the operator views the roadway. When a similarly equipped vehicle approaches, the light emitted there-from is crosspolarized with respect to the visor thereby reducing glare. For such a system to be effective, however, it must be adopted universally. Representative examples of the polarizing system may be found in U.S. Pat. Nos. 1,786,518; and 2,423,321. Also see commonly assigned U.S. Pat. No. 2,458,179. The second type of glare control system may be referred to as the strobe type. In the strobe system, the headlight is rapidly flashed on and off, either electrically by interrupting power or electromechanically by providing an oscillating or rotating shutter in front of the headlights, and the operator views the roadway through a visor that is rapidly switched between light transmissive and opaque states in synchronism with the headlights. The headlights operate above the eye flicker rate and generally are on for a very short portion of the headlight cycle. For example, the headlight may be turned on for 10 per cent of the cycle and be off for 90 per cent. The visor is transmissive while the headlight is on and then is rapidly switched to the opaque state while the headlight is off. Obviously, the light output of the headlight must be 10 times greater than normal to provide sufficient illumination. Because the visor is transmissive for only 10 per cent of the visor cycle, headlight glare from oncoming vehicles is reduced by 90 per cent. Despite the complexity of the strobe system, it has a major advantage in the fact that it need not be universally adopted to provide the benefit of glare suppression. For representative examples of early strobe type systems, reference may be had to U.S. Pat. Nos. 2,131,888; 2,139,707; and 2,755,700. A more contemporary version of the strobe type glare reduction system may be found in The National Highway Traffic Safety Administration Report PB-257-431 of September 1976 entitled "Advanced Headlighting Systems". The visor used in that system is of the electro-optical type, such as the PLZT shutter described in U.S. Pat. No. 3,245,315. While both the polarizing and strobe type glare control systems are effective to reduce glare, the inherent light transmission losses of those systems generally tend to deprive the vehicle operator of the benefit of supplemental ambient illumination provided by streetlights especially when there is no vehicle approaching or when the glare intensity is relatively low from oncoming vehicles off in the distance. The polarizing system described in the previously noted U.S. Pat. No. 2,230,262 addresses the problem by configuring the headlight and visor filters in venetian blind arrays that are switched between closed and opened positions in accordance with the glare intensity of the oncoming path as measured by a photoelectric glare level detector mounted on the front of the automobile. When the glare level is above a predetermined limit, the filters are closed for maximum glare reduction. When the glare intensity falls below the limit, the filters are opened to take advantage of ambient illumination. However, because this is a bistable system (the filters are either opened or closed) which does not adjust proportionally to variations in glare intensity, it would seem that the abrupt changes in perceived roadway illumination may prove tiring to the vehicle operator. The strobe type systems in the prior art generally do not make any provision for varying the system response in accordance to glare intensity and the transmissive-to-opaque time ratio of the visor cycle is fixed to coincide with the light emitting and nonemitting intervals of the headlight cycle for maximum glare reduction. The glare control system for reducing headlight glare from oncoming vehicles being of the type wherein the headlights are rapidly switched between light emissive and non-emissive states and the operator views the roadway through a visor operating in synchronism with the headlights and being switchable between light transmissive and opaque states could have technical difficulties when approached by two vehicles with different light emissive and non-emissive states. Previous methods for reducing headlight glare have generally been complex. Generally, previous glare reducing systems have no effect on headlight glare reflected by the vehicles mirrors from following vehicles. The apparatus disclosed in U.S. Pat. No. 4,707,767 is a multiple light unit with that being the only similarity. There is no reference to glare reduction. No glare reducing lenses are incorporated. U.S. Pat. No. 4,707,767 is designed specifically to provide for improved aerodynamic performance of the motor vehicle using same and for ease of replacement of the modules employed therein, unrelated to glare reduction. Automotive headlights over the years have been improved with better lighting for the driver and with each improvement for the driver it has brought with it more glare and blinding effects to approaching drivers. Today headlight glare is still a persistent safety hazard in night driving despite the many systems that have been proposed over the years to suppress headlight glare indicating the systems are either technically unfeasible, impractible or unsound or lacking in commercial potential. OBJECTS AND ADVANTAGES Accordingly, several objects and advantages of my invention are: (a) to provide an improved construction and arrangement of parts for reducing glare from an automotive headlight system and similar sources of light in an efficient and economical manner. (b) to provide a means for diminishing or eliminating the glare from sources of illumination by interposing between a light source and the person viewing said source a diffusive light transmitting solid lens or lenses of a suspension solution or mixture of particle or substance suspending material. (c) to provide a means in connection with a new automotive headlight system and the like for the projection of two light components from each headlight, one component being projected as that portion of the beam illuminating the roadway path of the vehicle, the other component being projected as a spread beam to illuminate the sides of the roadway. (d) to provide a glare reducing means in connection with a new automotive headlight system and the like for the projection of a single beam of light of reduced size utilizing a funnel design to reduce a conventional light source to a much smaller diameter. The smaller funnel end or light projection end of the funnel and the lens incorporated could be of any size or any shape as the light source could be of any size or shape. The lens and the light source or headlight could be of the same size and shape thus eliminating the funnel piece. (e) to provide a manner in which headlight glare is substantially reduced, as the only components remaining visible to an approaching driver and his or her passengers is the soft, low-glaring components of the emitted beam. (f) to provide adequate roadway illumination. (g) to provide a wider field of light for more side of the road illumination. (h) to provide more side of the road illumination to provide better vision for seeing bicyclists, pedestrians, animals and other objects. (i) to provide glare reduction to oncoming vehicles traveling along an adjacent path. (j) to provide glare reduction to oncoming vehicles traveling in any and all directions. (k) to provide glare reduction to vehicles being followed because high glare will not be present to be reflected by the lead vehicle mirrors. (l) to provide glare reduction to bicyclists, pedestrians and animals. (m) to provide a low glare automotive headlight system to reduce for passing motorists the temporary blindness or impaired or restricted vision that occurs when passing a vehicle in the opposing direction with high glare headlights. (n) to provide a low glare automotive headlight system that is self-contained, that does not require parts to be installed on other vehicles. (o) to provide a low glare automotive headlight system that does not have to be used universally to be effective. (p) to provide a low glare automotive headlight system where universal usage could be adapted over a period of time. (q) to provide a low glare automotive headlight system that does not cause abrupt changes in roadway illumination. (r) to provide a low glare automotive headlight system that utilizes no moving parts. (s) to provide a low glare automotive headlight system that utilizes no electronic components. (t) to provide a low glare automotive headlight system that utilizes no visors in the system. (u) to provide a low glare automotive headlight system that the headlights do not have to be switched on and off constantly as in some previous systems. (v) to provide a low glare automotive headlight system that the output of headlights used does not have to be increased 10-20 times as in some prior art. (w) to provide a low glare automotive headlight system that is simple in its operation. (x) to provide a low glare automotive headlight system that is relatively simple to install. (y) to provide a low glare automotive headlight system that does not deprive the vehicle operator of the benefit of supplemental ambient illumination provided by streetlights or other sources of illumination. SUMMARY OF THE INVENTION The present invention provides an improved light glare reducing device usable on any automobile or other vehicle or other similar spot like illumination light or other illumination lights. The present invention reduces headlight glare to oncoming vehicles traveling along an adjacent path of travel as well as any and all vehicles traveling in any and all other directions as well as to bicyclists, pedestrians and animals. These advantages are achieved according to the present invention, which comprises a light glare reducing device adapted to be placed in the path of light emitted from a light source. The glare reducing device includes a compartment with a plurality of light transmitting surfaces. The compartment substantially filled with a diffusive light transmitting solid lens or lenses of a suspension solution or mixture of particle or substance suspending material. BRIEF DESCRIPTION OF THE DRAWINGS The foregoing system is subject to considerable variation without departing from within the scope of the invention. Additional objects and advantages will in part appear and in part be pointed out in the course of the following detailed description of certain embodiments of the invention, which are given as nonlimiting examples, reference should be had to the following detailed description taken in connection with the accompanying drawings in which: FIG. 1 shows a front view of a single unit of a prototype test model. FIG. 2 shows sides, bottom and top views of a single unit of a prototype test model. FIG. 3 shows a perspective view of a single unit of a prototype test model. FIG. 4 shows a front view of an inner cylinder lens. FIG. 5 shows sides, bottom and top views of an inner cylinder lens. FIG. 6 shows a perspective view of an inner cylinder lens. FIG. 7 shows a front view of an outer cylinder lens. FIG. 8 shows sides, bottom and top views of an outer cylinder lens. FIG. 9 shows a perspective view of an outer cylinder lens. FIG. 10 shows a front view of a four unit prototype test model. FIG. 11 shows a side, bottom and top views of a funnel shaped adaptation used to reduce the size of a conventional light source to a much smaller size or diameter. FIG. 12 shows a front view of a funnel shaped adaptation used to reduce the size of a conventional light source to a much smaller size or diameter. FIG. 13 shows a rear view of a funnel shaped adaptation used to reduce the size of a conventional light source to a much smaller size or diameter. FIG. 14 shows a cutaway side view of a modification of a light glare reducing device adapted to a street light or other light source. FIG. 15 shows a top view of a modification of a light glare reducing device adapted to a street light or other light source. FIG. 16 shows a bottom view of a modification of a light glare reducing device adapted to a street light or other light source. REFERENCE NUMERALS IN DRAWINGS 30 inner cylinder 32 outer cylinder 34 inner cylinder lens 36 outer cylinder lens 40 prototype test model unit 42 inner and outer cylinder rear plate 44 inner cylinder compartment 46 outer cylinder compartment 48 funnel-shaped body 52 headlight 54 light source end 60 light bulb 62 light reflector shield DETAILED DESCRIPTION OF INVENTION FIG. 1 shows a front view, FIG. 2 shows side, bottom and top views and FIG. 3 shows a perspective view of a single unit of prototype test model 40. Inner cylinder 30 is a common two inch inside diameter white plastic or PVC water pipe. In prototype test model 40 inner cylinder 30 is three inches in length and is painted satin black on the inside and outside. Outer cylinder 32 is a common six inch inside diameter green plastic or PVC sewer pipe. In prototype test model 40 outer cylinder 32 is three inches in length and is painted satin black on the inside. Inner and outer cylinder rear plate 42 is a common piece of one-eighth inch thick clear light transmitting material (e.g., a common synthetic resin material such as PLEXIGLASS® can be used) cut in a circular shape and size fitting the outside diameter of outer cylinder 32. The rear end of inner cylinder 30 is glued in a centered position to one side of inner and outer cylinder rear plate 42. All glued areas should and must create a sealed tight joint if the lenses are molded in the inner or outer cylinders. Outer cylinder 32 is glued, outside of inner cylinder 30, to the outer edges of inner and outer cylinder rear plate 42. Outer cylinder 32 is glued to the same side of inner and outer cylinder rear plate 42 as inner cylinder 30. All glued areas should and must create a sealed tight joint if the lenses are molded in the inner or outer cylinders. Inner cylinder lens 34 is made from a mixture of eight ounces of polyester resin with hardener or catalyst added, resin solution UN-1866 by Mahogany Co. of Mays Landing, Inc., 5450 Atlantic Ave., Mays Landing, N.J. or an equivalent, and one-quarter teaspoon of liquid concentrated ultra CHEER with advanced color guard free, a household laundry detergent made by Proctor & Gamble, Cincinnati, Ohio 45202 or equivalent. The mixture is mixed well, poured into a mold to a thickness of one and one-quarter inches and allowed to harden. An alternative inner cylinder lens 34 is made from a mixture of eight ounces of polyester resin with hardener or catalyst added, resin solution UN 1866 by Mahogany Co. of Mays Landing, Inc., 5450 Atlantic Ave., Mays Landing, N.J. or an equivalent, and one-eighth teaspoon of liquid concentrated ultra CHEER with advanced color guard free, a household laundry detergent made by Proctor & Gamble, Cincinnati, Ohio 45202 or equivalent. The mixture is mixed well, poured into a mold to a thickness of two and three-quarter inches and allowed to harden. An alternative inner cylinder lens 34 is made from a mixture of eight ounces of polyester resin with hardener or catalyst added, resin solution UN 1866 by Mahogany Co. of Mays Landing, Inc., 5450 Atlantic Ave., Mays Landing, N.J. or an equivalent and one-eighth teaspoon of liquid concentrated ultra CHEER® with advanced color guard free, a household laundry detergent made by Proctor & Gamble, Cincinnati, Ohio 45202 or equivalent. The mixture is mixed well, poured into a mold to a thickness of three and three-eights inches and allowed to harden. The mold can be the inner cylinder 30 or the mold can be a separate mold and then the inner cylinder lens 34 placed in the inner cylinder 30. Outer cylinder lens 36 is made from a mixture of eight ounces of polyester resin with hardener or catalyst added, resin solution UN 1866 by Mahogany Co. of Mays Landing, Inc., 5450 Atlantic Ave., Mays Landing, N.J. or an equivalent, and one-quarter teaspoon of liquid concentrated ultra CHEER® with advanced color guard free, a household laundry detergent made by Proctor & Gamble, Cincinnati, Ohio 45202 or equivalent. The mixture is mixed well, poured into a mold-to a thickness of two inches and allowed to harden. The mold can be the outer cylinder 32 or the mold can be a seperate mold and then the outer cylinder lens 36 placed in outer cylinder 32. Since certain changes may, can and will be made in the above solutions or diffusive light transmitting solid lens or lenses of a suspension solution or mixture of particle or substance suspending material without departing from the scope of the invention herein involved, it is intended that all matter contained in the above solution descriptions and solutions shall be interpreted as illustrative and not in a limiting sense. Headlight 52 is placed at the rear end, light source end 54, of prototype test model 40 in such a way and manner that the illumination from headlight 52 is directed directly at and into the rear end, light source end 54. The illumination light from headlight 52 passes through inner cylinder compartment 44 and outer cylinder compartment 46. Prototype test model 40 uses a 100 watt fog light as a headlight 52. Examples are a Wagner number 4537 and a GE number 4537-2 bulbs. Since certain changes may, can and will be made in the above solutions or diffusive light transmitting solid lens or lenses of a suspension solution or mixture of particle or substance suspending material without departing from the scope of the invention herein involved, it is intended that all matter contained in the above solution descriptions and solutions shall be interpreted as illustrative and not in a limiting sense. FIG. 4 shows a front view, FIG. 5 shows side, bottom and top views and FIG. 6 shows a perspective view of an inner cylinder lens 34. FIG. 7 shows a front view, FIG. 8 shows side, bottom and top views and FIG. 9 shows a perspective view of an outer cylinder lens 36. FIG. 10 shows a front view of the four unit prototype test model 40. The four unit prototype test model 40 consists of four single unit prototype test models 40 placed in a side by side manner to form a streight line of units. Since certain changes may, can and will be made in the aforementioned without departing from the scope of the invention herein involved, it is intended that all matter contained in the above and the above number of single unit prototype test models 40 units shall be interpreted as illustrative and not in a limiting sense. FIG. 11 shows side, bottom and top views, FIG. 12 shows a front view and FIG. 13 shows a rear view of a single unit of prototype test model utilizing a non-transparent funnel-shaped body 48 to direct the headlight 52 illumination into an inner cylinder diffusive lens 34' and thereby eliminating outer cylinder lens 36. With this arrangement, the light from the headlight 52 is directed toward and passes through the diffusive lens 34'. Thus, oncoming traffic will only see the diffused light emanating from the lens 34'. The lens 34' can be made to fit snugly in the small opening of the body 48 without permanent adhesives so that lenses of varying degrees of diffusivity can be used and easily interchanged for adapting to different environments. Should the headlight 52 be reduced in size, the funnel-shaped body of the prototype test model can be eliminated. With a headlight 52 reduced in size, inner cylinder lens 34 can be any shape or size to match any shape or size headlight 52. FIG. 14 shows a cutaway side view, FIG. 15 shows a top view and FIG. 16 shows a bottom view of a modification of a light glare reducing device adapted to a street light or other light source. The device includes a light bulb 60 and a light reflector shield 62 for directing light through the light glare reducing portion. A modification of a light glare reducing device adapted to a street light or other light source could be turned sideways, upside down or any combination of same due to its sealed construction. Other light sources would include and not be limited to spot lights, utility lights and household light bulbs. Prototype test model 40 or similar models could be adapted to fit and to be attached to any household, business or public use spotlight. Since certain changes may, can and will be made in the above construction and different embodiments of the invention and could be made without departing from the scope of the invention herein involved, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. Light glare and light projections or illumination would very depending upon any and all changes in suspension solutions or mixtures of particle or substance suspending material and by any and all changes in illumination sources or headlights 52 and light glare and light projections or illumination could change by any and all changes or modifications in designs. OPERATION OF INVENTION The light glare reducing device demonstrates the feasibility of a low glare headlight for automotive usage and low glare feasibility for other lights. The high glare of current automotive headlights 52 is not present with this light glare reducing device. The blinding effect to approaching drivers is reduced. The blinding effect to bicyclists, pedestrians, animals and all others is reduced. In the light glare reducing device the center direct bulb illumination of the front side of the filament is directed into inner cylinder 30 along with some of the reflective light from the center rear portion of the reflective inside surface. The outside area of the reflective inside surface reflects light from the bulb toward and into outer cylinder 32. A diffusive light transmitting solid lens or lenses of a suspension solution or mixture of particle or substance suspending material in inner cylinder compartment 44 and in outer cylinder compartment 46 cuts or reduces the light glare effects of headlight 52 units much as a cloud will cut the glare of the sun. The total output of the light is reduced just as the brightness of the sun is reduced by a cloud. Therefore a brighter bulb or headlight 52 is required when projected through this invention to obtain the same amount of illumination. The brightness of any headlight 52 has to be measured at the front of the lens or lenses and not by the headlight 52 alone. Since certain changes may, can and will be made with resulting improvements in a diffusive light transmitting suspension suspended transmitting solid lens or lenses of a suspension solution or mixture of particle or substance suspending material without departing from the scope of the invention herein involved a one compartment light glare reducing device could result for automotive headlight 52 and other spotlight usages as could be used for a light bulb 60. A low glare light can be obtained from the following combinations; (a) an inner cylinder lens 34 made from a mixture of eight ounces of polyester resin with hardener or catalyst added, resin solution UN 1866 by Mahogany Co. of Mays Landing, Inc., 5450 Atlantic Ave., Mays Landing, N.J. or an equivalent, and one-quarter teaspoon of liquid concentrated ultra CHEER with advanced color guard free, a household laundry detergent made by Proctor & Gamble, Cincinnati, Ohio 45202 or equivalent. The mixture is mixed well, poured into a mold to a thickness of one and one-quarter inches and allowed to harden. (b) an inner cylinder lens 34 made from a mixture of eight ounces of polyester resin with hardener or catalyst added, resin solution UN 1866 by Mahogany Co. of Mays Landing, Inc., 5450 Atlantic Ave., Mays Landing, N.J. or an equivalent, and one-eighth teaspoon of liquid concentrated ultra Cheer with advanced color guard free by Proctor & Gamble, Cincinnati, Ohio 45202 or equivalent. The mixture is mixed well, poured into a mold to a thickness of two and three-quarter inches and allowed to harden. (c) an inner cylinder lens 34 made from a mixture of eight ounces of polyester resin with hardener or catalyst added, resin solution UN 1866 by Mahogany Co. of Mays Landing, Inc., 5450 Atlantic Ave., Mays Landing, N.J. or an equivalent and one-eighth teaspoon of liquid concentrated ultra Cheer with advanced color guard free by Proctor & Gamble, Cincinnati, Ohio 45202 or equivalent. The mixture is mixed well, poured into a mold to a thickness of three and three-eights inches and allowed to harden. (d) an outer cylinder lens 36 made from a mixture of eight ounces of polyester resin with hardener or catalyst added, resin solution UN 1866 by Mahogany Co. of Mays Landing, Inc., 5450 Atlantic Ave., Mays Landing, N.J. or an equivalent, and one-quarter teaspoon of liquid concentrated ultra Cheer with advanced color guard free by Proctor & Gamble, Cincinnati, Ohio 45202 or equivalent. The mixture is mixed well, poured into a mold to a thickness of two inches and allowed to harden. Many other combinations of mixtures or suspended solutions as well as other containers or cylinders are sure to exist. Since certain changes may, can and will be made in the above solutions or diffusive light transmitting solid lens or lenses of a suspension solution or mixture of particle or substance suspending material without departing from the scope of the invention herein involved, it is intended that all matter contained in the above solution descriptions and solutions shall be interpreted as illustrative and not in a limiting sense. The automotive headlight lens when used with a General Electric 4537-2, 12 volt, 100 watt sealed beam or equivalent substanially reduces the glare of the 4537-2 light source below the glare from a 4001 high beam, sealed beam from a four headlight automotive system. The light or illumination is also reduced. When used in multiple units of four to six units of 4537-2 sealed beams with lenses the light or illumination is increased to a level adequate to safely drive a motor vehicle while maintaining a reduced glare level as compared to a standard two light low beam headlight system. The lens is made from a mixture of eight ounces of polyester resin with hardener or catalyst added, resin solution UN 1866 by Mahogany Co. of Mays Landing, Inc., 5450 Atlantic Ave., Mays Landing, N.J. or an equivalent, and one-quarter teaspoon of liquid concentrated ultra CHEER® with advanced color guard free, a household laundry detergent made by Proctor & Gamble, Cincinnati, Ohio 45202 or equivalent. The Mixture is mixed well, poured into a mold to a thickness of one and one-quarter inches and allowed to harden. The lens can be of any size or shape as to fit the light source. With 4537-2 sealed beam the lens would be round. With rectangular or other shaped light sources the lens would be shaped to fit. Adaptations can also be made to reduce the size or change the shape between the light source and the lens. All measurements and structural designs are subject to changes and adaptations as for example, the round shape could be changed to a rectangular shape to accommodate rectangular shaped sealed beam headlights 52. The separate units could be combined to make a single unit. The lengths used could be changed to accommodate and to best use other various suspended solutions. This product would be considered an after-market product before and after such time as vehicle manufacturers initiated the product into their designs. One problem that currently occurs on automotive headlights 52 is that snow and ice can build up on the headlights 52 and thereby restricting the light that is available. Since the light glare reducing devices would not have the sealed beam heat to help eliminate some or all of this snow or ice, wiper blades can and should be provided to eliminate this potential problem in cold climate regions. Small wiper units similar to units now available on some cars could be used. On current vehicles the existing headlights 52 could be maintained so that the high beams are available should driving circumstances allow their safe usage and for a backup or reserve lighting system or the new lighting system could be installed where the current headlight system exists. The use of this product would show consideration for approaching drivers visibility. CONCLUSION, RAMIFICATIONS AND SCOPE OF INVENTION Thus the reader can see that the present light glare reducing device provides an improved low glare illumination device usable on any automobile or other vehicle for reducing headlight 52 glare to oncoming vehicles traveling along an adjacent path of travel as well as any and all vehicles traveling in any and all other directions as well as to bicyclists, pedestrians and animals. The present light glare reducing device used in a single unit or in multiple units in any configuration could be adapted to fit and to be attached to any streetlight, any household, business or public use spotlight or lighting system. The present light glare reducing device could be adapted and modified to be used with any household light bulb and other illumination devices. Although the description above contains many specifications, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the presently preferred embodiments of this invention. Many other variations are possible. For example, inner cylinder compartment 44 and outer cylinder compartment 46 can have other shapes, such as square, oval, triangular and so on; the two compartments could become one compartment with a light transmitting solid lens or lenses of a suspension solution or mixture of particle or substance suspending medium without departing from the scope of the invention herein involved, a one compartment light glare reducing device could result for automotive headlight 52 and other spotlight usages as could be used for a light bulb. Glass could be used as a construction material. The invention could be mounted on a vehicle hood, inside the vehicle on the dash or attached to the underside of the roof, attached to the grill, in the grill, on the bumper, in the bumper, as a replacement of existing lighting units, etc. Thus the scope of the invention should be determined by the appended claims and their legal equivalents, rather than by the examples given or by the embodiments illustrated. Since certain changes may be made in the above construction and different embodiments of the invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense, and that the claims are intended to cover all changes and modifications. It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention which as a matter of language might be said to fall there between.

A light glare reducing device being all or partially constructed of light transmitting materials with light reflecting surfaces in different designs. When the light glare reducing devices or lenses are placed over lighting sources they reduce the high glare and blinding effects of the light sources. Increasing the light output of lighting sources when used with lenses can maintain the lighting level while reducing glare. When used for automotive usage alternative automotive headlights are used. The combined usage of the alternative headlights and the lenses provides roadway and side of the roadway lighting without high glare to oncoming vehicles, bicyclists, pedestrians and animals. The existing automotive headlight system can be maintained so that the high beam headlights can be used if necessary or desirable.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a switching device. 2. Description of the Prior Art. Switching devices, particularly thermally actuatable switches, have gained widespread use in numerous applications to prevent appliances, electrical and electronic equipment from generating unsafe temperatures. In general, such switches employ a conductive bar or bridge member which is releasably positioned to close and open a circuit between two leads. Positioning of the conductive bar is accomplished by means of springs responsive to the state or condition of a temperature sensitive member, typically a pellet of material which shrinks in size or melts at a given temperature. So long as the pellet is in a particular state or condition, the circuit between the leads via the conductor is closed. When the pellet reaches another predetermined state or condition, generally melting of the pellet, the conductive bar is released from contact with the leads and the circuit is opened. Release of the bar is effected by actuation of springs or the like which are responsive to the condition or state of the pellet. One such thermal cut-off device is described in U.S. Pat. No. 3,952,274. Such device utilizes a conductive spring blade operatively connected to one of two leads. The spring blade is normally biased away from the other lead. This normal bias is overcome by a biasing member which engages a temperature sensitive pellet. If the pellet shrinks or melts, the force exerted by the biasing member is insufficient to overcome the biasing force of the spring blade. Consequently, the spring blade moves away from the other lead opening the circuit. It can be seen that such a device relies upon a pair of springs which act directly and oppositely on each other. This requires selecting springs which will cooperatively exert the requisite forces at each stage or condition of the temperature sensitive pellet. U.S. Pat. No. 3,956,725 describes a similar thermal cut-off switch utilizing a combination of cooperatively opposing spring members to position a conductor in open and closed circuit relationship to a pair of leads. SUMMARY The temperature sensitive pellets employed in such thermal cut-off switches are selected on the basis of their melting point or range. The switch is located in thermally conductive proximity to an element whose temperature is to be monitored. Melting of the pellet is the circuit opening triggering event. However, the material of which the pellet is made may shrink due to sublimation or for some other reason, in which case the effect of the pellet on one or more of the springs involved in positioning the circuit completing conductive bar may be changed. Depending upon the degree of shrinkage and the relationship of the springs, the circuit may be opened although the melting temperature of the pellet has not been reached. It is thus desirable to provide a circuit opening mechanism which will accommodate some shrinkage in the pellet, but beyond that will provide for opening of the circuit. Other features desirable in a thermal cut-off switch of the type herein described are simplicity of design, fail-safe capabilities, compactness and convenient insertion into the electrical circuitry at a locality thermally proximate to the element or area to be monitored. It is an object of this invention to provide a thermal cut-off switch in which opening and closing of the circuit is accomplished by independently acting members. A further object is the provision of such a switch providing a degree of accommodation for shrinkage of the temperature sensitive element. A still further object is the provision of a thermal cut-off switch which is compact, simple in design, has fail-safe features and is conveniently attachable to a variety of surfaces. These and other objects are provided by a switch comprising a housing providing a cavity, at least two lead means extending into said cavity, electrical conductor means for selectively completing an electrical circuit between said lead means, a switch activating member, first and second biasing means, and isolating means for isolating said first biasing means from said second biasing means, said device having a circuit completing state wherein said switch activating member is in a first state and said first biasing means acting independent of said second biasing means exerts a force on said electrical conductor to complete said circuit, and a circuit opening state wherein said switch activating member is in a second state and said second biasing means acting independent of said first biasing means exerts a force on said electrical conductor to open said circuit. In preferred embodiments, the switch-activating member is a pellet of material meltable or softenable at a given temperature or within a given range generally substantially above room temperature. The first and second biasing means are springs which are operationally isolated from each other so as to operate independent of each other. While the switch activating member is in its circuit closing state, the first biasing means (spring) acts solely on the conductor means. When the pellet reaches the circuit breaking state, the first spring is neutralized so to speak and the second biasing means urges the conductor away from the leads, breaking the electrical circuit. The isolating means is preferably a frame member having opposing ends, one of which rests atop the pellet and the other of which is engaged by the second biasing means. The first biasing means as well as the conductor means are preferably confined within the isolating means. When the pellet reaches the circuit opening state, the action of the first spring is neutralized and the second spring alone exerts a force which moves the conductor means to a position whereby the circuit is broken. Drawings are provided wherein: FIG. 1 is a perspective view of a preferred embodiment of the invention; FIG. 2 is an exploded view of the various elements of the embodiment depicted in FIG. 1; FIG. 3 is a sectional view taken along line 3--3 of the embodiment of FIG. 1; FIG. 4 is a sectional view taken along line 4--4 of FIG. 3; FIG. 5 is a sectional view taken along line 5--5 of the embodiment of FIG. 1 with the elements shown in an initial circuit completing state; FIGS. 6 and 7 are sectional views similar to FIG. 5 in different, later stages of operation; FIG. 8 is a side elevation view illustrating mounting of the embodiment of FIG. 1; FIG. 9 is a longitudinal sectional view of another embodiment of the invention; FIG. 10 is a longitudinal section of still another embodiment of the invention; FIG. 11 is a side elevation view with some parts shown in section of the device of this invention in combination with an insulator element; and FIG. 12 is an isometric view of an embodiment of the invention mounted and schematically depicted in an electrical circuit. DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, the device 20 includes a case 22 defining a main body portion 24. Case 22 is preferably constructed of a thermally and electrically conductive material, e.g., a metal such as aluminum of a zinc alloy. A pair of parallel leads 26 and 28 including spade terminals 30 and 32 and a portion of posts 34 and 36 respectively, extend from end 38 of the main body portion 24. End 38 is provided by an electrically insulating potting compound which together with case 22 preferably completely encases the remaining elements of the device 20. In FIG. 2, from bottom to top, the case 22, having peripheral retaining tabs 40, defines a cavity 42. An insert 44 nests in cavity 42. Insert 44, which is made of a rigid, electrical insulating material, is provided with a recess 46 shaped to receive and retain the various operating elements of the device in electrical isolation from case 22 (except for the temperature sensitive pellet). Cylindrical-shaped pellet 48 is slidably fitted in a central, longitudinally extending channel 49 of recess 46. Disposed above pellet 48 is a cylindrical-shaped member 50 having opposing, generally flat, parallel ends 52 and 54. When in position, end 52 engages the proximate end of pellet 48. Member 50 is provided with opposing, longitudinally extending slots 56 and 58 defined by opposing sidewalls 60 and 62. End 54 of member 50 is formed by crimping T-shaped tabs 64 and 66. In doing so, transverse slots 68 are provided between end 54 and sidewalls 60 and 62. A compression spring 70 of suitable dimensions is positioned within member 50. Between spring 70 and end 54 is located conductor bar 72 having a central, circular-shaped section 74 from which extends opposing rectangular-shaped sections 76 and 78. Conductor bar 72 is dimensioned such that it is slidably retained within member 50, the central section 74 being confined laterally within walls 60 and 62 and longitudinally between ends 52 and 54. Sections 76 and 78 extend through and are slidable along slots 56 and 58. Spring 70 urges conductor bar 72 upwardly towards end 54 of member 50. A second compression spring 79 is positioned above member 50, and exerts a downward biasing force against end 54 of member 50. An insulating plate 80 preferably of ceramic composition, dimensioned to fit atop insert 44 and confine spring 79 in recess 46 is provided with parallel slots 82 which communicate with slots 84 of recess 46 in insert 44. Posts 34 and 36 are dimensioned for slidable insertion through slots 82 and 84 into the interior of recess 46. Plate 80 is optionally fitted with a central downward directed nipple 85 (see FIG. 3) which aids in positioning and retaining spring 79 in place. Ends 86 of posts 34 and 36 are preferably slightly curved for reasons mentioned hereinafter. Intermediate each of the ends 86 and the shoulders of terminals 30 and 32 are opposing angular projections 90 which serve to securely mount and orient leads 26 and 28 in recess 46. Between projections 90 and ends 86 are spring tabs 92 which upon insertion of leads 26 and 28 are depressed so as to be flush with the sides of posts 34 and 36. After the posts 34 and 36 are inserted into recess 46 the desired distance (i.e., through insulating plate 80), the spring tabs 92 are freed from lateral constraints and extend laterally inwardly from posts 34 and 36 due to their normal biasing action to lock leads 26 and 28 in place. In FIG. 3, the various elements depicted in FIG. 2 are shown in location. Mounted longitudinally at the extreme lower end of channel 49 is pellet 48. End 52 of member 50 rests atop and in engagement with pellet 48. Spring 70 is in a compressed or loaded state, being confined between conductor bar 72 and end 52 of member 50. Conductor bar 72 is held in position spaced from end 54 of member 50 by means of ends 86 of leads 26 and 28 which press against sections 76 and 78 of conductor bar 72. The space between end 54 and conductor bar 72 is determined by the height of pellet 48 and the distance leads 26 and 28 extend into recess 46. Except for pellet 48, insert 44 and plate 80 electrically insulate the elements positioned in recess 46 from case 22. As seen in FIG. 4, leads 26 and 28 contact conductor bar 72 proximate the ends 76 and 78, respectively. FIGS. 5, 6, and 7 depict the preferred embodiment in three stages of operation. In FIG. 5, pellet 48 is shown in its circuit completing state, that is, it is in solid form and occupies such a depth of channel 49 that conductor bar 72 is urged against ends 86 of leads 26 and 28 to provide a completed circuit between such leads. As noted above, ends 86 of leads 26 and 28 have a slight convex curvature. This shape affords a better electrical contact between ends 86 and bar 72 than would be achieved if ends 86 were entirely flat. The dimensions of the channel 49, member 50, leads 26 and 28 and pellet 48 are such that bar 72 is spaced from end 54 of member 50 a predetermined distance designated by the numeral 88 in FIG. 5. In FIG. 6, Pellet 48 has decreased in length an amount equal to the distance 88. This shortening of pellet 48 may be due to sublimation over a period of time. End 52 of member 50 remains engaged with pellet 48 due to the action of spring 79. The net result is that the bottom of end 54 moves into engagement with conductor bar 72. It can now be seen that spring 70 has reached its neutralized (yet not unloaded) state with respect to bar 72 and that any further reduction in the depth of channel 49 occupied by pellet 48 or a reduction in the force exerted by pellet 48 on member 50 such as if pellet 48 were to soften substantially or melt would result in further downward movement of member 50 and initial downward movment of confined bar 72. Thus, in FIG. 6, pellet 48 is at the limit of its circuit completing state. In FIG. 7, pellet 48 has undergone a change in state (e.g., further shrinkage due to sublimation, or melting), and is now in what may be termed a circuit opening or breaking state. Spring 79 continues to urge member 50 downwardly and consequently also bar 72. The electrical contact with leads 26 and 28 is broken and the circuit opens. It is noteworthy that electrical contact is broken at both leads 26 and 28. This is desirable since welding of one of the leads to the conductor bar will not prevent the circuit from being broken. FIG. 8 illustrates mounting of device 20 to a plate 93. Extending from the main body portion 24 of case 22 is a mounting plate 94 bored to receive a screw 96 or similar mounting means. Forward of mounting plate 94 and extending angularly from body portion 24 is an orientation tab 98 which is inserted in an opening in plate 93. Main body portion 24 is thus upwardly angularly disposed with respect to plate 93, so that terminals 30 and 32 are completely clear of plate 93 to minimize the chances of shorting out the device at the terminal connection. FIG. 9 illustrates another embodiment with like elements to those of the device of FIGS. 1-8 being given like numerals. The embodiment of FIG. 9 utilizes essentially the same elements of the preferred embodiment except that member 50 has only one sidewall 60. The embodiment of FIG. 10 (with like elements being given like numerals) differs from the previous embodiments in that the functional equivalent of member 50 is central, longitudinal extending post 102 surrounding which is spring 70. FIG. 11 illustrates the device 20 inserted in mounting insulator 104. Lead 26 has a right-angle bend in post 34. In FIG. 12, the device 20 is shown as part of an electrical circuit. Device 20, inserted in mounting insulator 104, is in turn, mounted on plate 106. A circuit 108 is provided including switch 110, thermostat 112, conductor pin 114 and switch 116. With switches 110 and 116 closed the circuit 108 is complete so long as the pellet 48 is in a circuit completing state. When pellet 48 converts to a circuit opening state such as by melting or shrinking in dimension beyond a predetermined amount, conductor bar 72 is urged away from mutual electrical contact with leads 26 and 28 and the circuit is broken. The device of this invention is primarily intended to serve as a thermal cut-off switch. It is mounted in thermally conductive proximity to the element or environment to be monitored. Generally, the device is mounted to a thermally and electrically conductive surface, although it may be mounted to electrical insulating surfaces such as ceramics or other organic or inorganic insulating materials. The pellet 48 may be made of any material responsive to the condition to be monitored. Suitable temperature-sensitive pellets are disclosed in U.S. Pat. Nos. 3,180,958, 3,291,945, and 3,519,972. Preferably, the pellet should have a reasonably sharp melting point and be electrically nonconductive. While melting of the pellet is the normal circuit breaking event, the composition of the pellet may be subject to shrinkage due to sublimation or other causes. The device of this invention is designed to compensate for such shrinkage, typically by as much as 50% of the initial length of the pellet. The significant feature of this invention is the independent operation of the springs 70 and 79 which allows both higher electrical contact forces and higher separation forces as a result of the nonopposing relationship of the springs. The pellet 48, which is in axial alignment with member 50 and springs 70 and 79, acts via member 50 as a reaction member for both springs 70 and 79. In a typical application, for a pellet having an initial height of 0.25 cm., spring 70 will exert a force of approximately two pounds. Upon the pellet reaching its circuit opening state, spring 79, acting upon end 54 of member 50 (as well as the now upwardly confined conductor bar 72), exerts a sufficient force to break contact with the leads. Since spring 70 has been neutralized at this point with respect to conductor bar 72, the force exerted by spring 79 is essentially the only force applied to conductor bar 72. Thus, spring 79 may have an intrinsic force rating greater than, equal to, or less than the intrinsic force rating of spring 70. Generally, spring 79 has a rating greater than spring 70, however, on the order of 2 to 4 pounds. As noted above, at least certain pellet compositions may be subject to shrinkage due to sublimation or the like. The device of this invention is preferably substantially gas tight, owing to the combination of case 22 and the potting compound forming end 38. The potting compound is poured into the cavity 42 after the device has been assembled. Epoxy resins represent a preferred potting compound. A potting compound should be selected which will not require temperatures for pouring and hardening which will interfere with operation of the device, particularly melting of the temperature-sensitive pellet. The insert 44 serves to limit travel of the conductor bar 72 and member 50 which, in the fully tripped position (pellet 48 being in the circuit opening state), has a clearance of approximately 0.04 cm. from the base of case 22. The design parameters which determine the size of the device of the invention include the desired contact force exerted by the spring 79 over a selected working range for pellet length variation, desired circuit opening force at minimum pellet working length, adequate gap between parts in the tripped or circuit opening position, and thicknesses for the various insulators and metal case. Since the pellet is generally allowed a shrink factor of 50%, the spring rate for spring 79 is the factor that determines how the spring force varies over an allowable length variation of 0.050 inch. The lower the spring rate, the more constant is the force. However, to achieve low spring rates, it is necessary to have a larger number of coils which greatly increases the length of the springs. Therefore, the desired spring characteristics of force and rate have the most influence on the size of the device. A high contact force for spring 70, e.g., one which varies from 2 pounds at initial pellet length to 1.3 pounds at 50% of initial length, insures low electrical resistance throughout the life of the device. A relatively high trip force exerted by spring 79 increases device reliability through the ability to separate contacts which may have become cold welded over a long period of time. The leads are supported and electrically insulated from the conductive case by insulator plate 80. Shoulders on the portion of the lead that passes through the insulator plate prevent inward movement when the lead is subjected to a pushing force. A pulling force is resisted by tabs 92 protruding from the side of the terminal. Tabs 92, which bear against the internal surface of the insulator plate 80, act as a leaf spring and deflect to a flush position as the leads pass through the rectangular-shaped slots 82 in the insulator plate 80. The leads shown in the drawings are standard 0.625 cm. blade type leads, although other lead configurations having crimp, screw, solder, or weld terminations can easily be installed. The case is extended a distance of 0.2 cm. beyond the external surface of the insulator plate 80 so as to form a well for the containment of the potting material while it hardens. This simplifies the potting operation and provides a thick section of potting material for increased gas tightness. Although the case is electrically insulated from the leads and mechanism by the two insulators 44 and 80, the pellet is in intimate contact with the case. This permits efficient heat transfer from the case to the pellet. Assembly of the device of this invention is readily apparent from FIG. 2. Member 50 is initially open at end 54. Spring 70 is positioned inside member 50 followed by placing conductor bar 72 in member 50 atop spring 70. Conductor bar 72 is pushed downwardly against spring 70. End 54 of member 50, which initially is in the form of opposing flaps, is formed by bending the flaps down and towards one another. Insert 44 is then dropped into case 22. Pellet 48 is then lowered into recess 46, followed by the member 50 subassembly. Spring 79 is then positioned in recess 46, followed by insulator plate 80. Insulator plate 80 is secured in place by bending tabs 40 into engagement with the chamferred edges of plate 80. Leads 26 and 28 are pushed through slots 82 of plate 80 until the projections 90 on posts 34 and 36 are seated against the upper surface of plate 80. The cavity between the plate 80 and the plane between opposing upper edges of case 22 is then filled with a suitable potting compound. The spring system of this invention provides a highly reliable, low cost thermal cut-off device. With high contact forces and trip forces, expensive plating on parts can be minimized, eliminated entirely, or replaced by lower cost plating materials. Design of the device is simplified in that the springs do not have to be carefully matched and, therefore, can be sized independently. Ample trip force can be designed into the trip spring (spring 79) to guard against the possibility of welded contacts. Member 50, with its hollow cage-like design, is one means of isolating springs 70 and 79 so that the force of trip spring 79 on conductor bar 72 is bypassed until the time of actuation. FIGS. 9 and 10 illustrate additional embodiments. A single pellet supporting both aligned springs as provided by the present invention represents a simple, reliable approach to operation of a thermal cut-off device.

A switch device utilizing independently acting biasing members to position a conductor to close a circuit between a pair of leads and maintain such closed circuit until a switch activating member such as a meltable pellet reaches a circuit opening state whereupon further independent biasing action causes the conductor member to assume a circuit open position.

TECHNICAL FIELD [0001] The present disclosure generally pertains to a seal between relatively movable parts and more particularly to a tandem dry gas seal suitable for use with a centrifugal compressor. BACKGROUND [0002] Seal systems are used in a wide variety of rotary shaft devices, such as blowers, compressors, and pumps, which have critical sealing requirements. Dry gas seal systems provide a barrier between the gas in the working chamber, or process gas, and the external environment to minimize the loss of process gas to the environment. Seal systems may include two stages of seals arranged in tandem to improve reliability. Mosley and Haynes, in European Patent Application publication EP 0 701 074 A1, describe a dry gas seal with two face seal stages of the same construction. [0003] Dry gas seals operate with very small gaps or separations between opposed sealing surfaces. Brittle materials such silicon or tungsten carbide are used for some sealing surfaces to provide precise surfaces for small separations between the opposed sealing surfaces. Such materials may, however, fail and a failure can be catastrophic. [0004] The present disclosure is directed toward overcoming one or more of the problems discussed above as well as additional problems discovered by the inventor. SUMMARY OF THE DISCLOSURE [0005] A seal assembly includes a primary seal stage and a secondary seal stage. The primary seal stage includes a primary ring arranged to be coupled to a housing and a mating ring arranged to be coupled to a rotating shaft. The primary ring and the mating ring of the primary seal stage are formed materials chosen to effectively block flow of gas through the seal assembly. The secondary seal stage is coaxially positioned with respect to the primary seal stage and includes a primary ring arranged to be coupled to the housing and a mating ring arranged to be coupled to the rotating shaft. The primary ring and the mating ring of the secondary seal stage are formed of materials chosen to survive a failure of the primary seal stage. The seal assembly may be used in a compressor for sealing a penetration of the compressor's shaft through the compressor's housing. BRIEF DESCRIPTION OF THE DRAWINGS [0006] FIG. 1 is a cutaway illustration of an exemplary centrifugal compressor. [0007] FIG. 2 is a cross-sectional view of a seal assembly according to an exemplary disclosed embodiment. DETAILED DESCRIPTION [0008] FIG. 1 is a cutaway illustration of an exemplary centrifugal compressor 100 . Process gas enters the centrifugal compressor 100 at a suction port 112 formed on a housing 110 . The process gas is compressed by one or more centrifugal impellers 122 mounted to a shaft 120 . The compressed process gas exits the centrifugal compressor 100 at a discharge port 114 that is formed on the housing 110 . [0009] The shaft 120 and attached elements such as the centrifugal impellers 122 are supported by bearings 132 installed on axial ends of the shaft 120 . Seal assemblies 142 are disposed about the shaft 120 inward of the bearings 132 . The seal assemblies 142 seal high pressure inside the centrifugal compressor 100 . Different designs may use more or fewer seal assemblies 142 . [0010] The seal assemblies 142 include primary and secondary seal stages. The primary seal stage normally operates to block the flow of the process gas out of the compressor. The secondary seal stage may be considered a backup to block the flow of the process gas out of the compressor in the event of failure or malfunction of the primary seal stage. In an embodiment, the secondary and primary seal stages are substantially identical but formed of different materials. [0011] FIG. 2 is a cross-sectional view of a seal assembly 142 . The elements of the seal assembly are generally ring shaped or radially disposed about a central axis of the seal assembly. FIG. 2 illustrates a cross-section of one side of a symmetrical seal assembly. The seal assembly may be used as the seal assemblies 142 of the centrifugal compressor 100 of FIG. 1 . The seal assembly of FIG. 2 includes a primary seal stage 30 and a secondary seal stage 50 . The primary seal stage 30 is disposed at an inner, or process gas, end of the seal assembly 142 . The secondary seal stage 50 is disposed at an outer, or bearing, end of the seal assembly 142 . [0012] The seal assembly is illustrated in FIG. 2 adjacent to a buffer seal 20 . The buffer seal 20 includes segmented carbon rings 21 , 22 held in a buffer seal housing 24 . Radial passages in the buffer seal housing 24 provide a purge inlet 15 . A secondary vent 17 is disposed between the buffer seal 20 and the secondary seal stage 50 . A primary vent 13 is disposed between the primary seal stage 30 and the secondary seal stage 50 . A primary inlet 11 is disposed on the process gas end of the primary seal stage 30 . [0013] When the seal assembly illustrated in FIG. 2 is used in a compressor, various gas flows exist during operation. In an embodiment, filtered process gas 12 flows into the primary inlet 11 . Some of the filtered process gas leaks through the primary seal stage 30 . The filtered process gas that leaks through the primary seal stage 30 passes out the primary vent 13 as a primary vent gas 14 which may then be collected or, for example, for natural gas, flared off A purge gas 16 , such as nitrogen, flows into the purge inlet 15 . Some of the purge gas flows past the segmented carbon ring 22 and out the secondary vent 17 as a secondary vent gas 18 . Some of the filtered process gas that leaked through the primary seal stage 30 also leaks through the secondary seal stage 50 and out the secondary vent 17 . [0014] The flows through or pressures in the primary inlet 11 , the primary vent 13 , the purge inlet 15 , and the secondary vent 17 are monitored to control operation of the seal. The monitoring can also be used to detect a malfunction or abnormal operation of the seal. A system monitoring the seal can shut down the compressor when abnormal operation is detected. [0015] The primary seal stage 30 includes a sleeve 5 . The sleeve 5 may be coupled to the shaft of a compressor. The sleeve 5 may be formed of a stainless steel. A mating ring 32 is disposed in an opening of the sleeve 5 . A sleeve O-ring 33 is disposed in a slot in the opening of the sleeve 5 . The sleeve O-ring 33 provides a static seal between the sleeve 5 and the mating ring 32 . The sleeve O-ring 33 may be made of a polymer, for example, polytetrafluoroethylene (PTFE). [0016] The primary seal stage 30 also includes a primary ring 31 disposed in an opening of a retainer 34 . The retainer 34 may be formed of a stainless steel. The retainer 34 may be coupled to the housing of a compressor. The primary ring 31 and the mating ring 32 include corresponding opposing faces. [0017] A spring 35 biases the primary ring 31 towards the mating ring 32 . Although one spring is illustrated in FIG. 2 , the primary seal stage 30 may have multiple springs circumferentially distributed around the central axis of the seal assembly 142 . The spring 35 may be formed of a superalloy. A spring plate 36 is disposed between the spring 35 and the primary ring 31 . A retainer O-ring 37 is disposed between the spring plate 36 and the retainer 34 and provides a static seal between the spring plate 36 and the retainer 34 . The retainer O-ring 37 may be made of a polymer, for example, PTFE. [0018] The mating ring 32 of the primary seal stage 30 is made of a brittle material. In an embodiment, the primary ring 31 of the primary seal stage 30 is also made of a brittle material. The primary ring 31 and the mating ring 32 may be made of the same material or different materials. The primary ring 31 and mating ring 32 of the primary seal stage 30 may be coated with additional materials, for example, the rings may be diamond coated. In another embodiment, the primary ring 31 is made of a more flexible material, such as a carbon composite. Brittle materials provide precise shapes that experience limited distortion during operation at high gas pressures, for example, 1000 PSI, high rotational speeds, for example, 20,000 RPM, and high temperatures, for example, 400° C. [0019] Ductile and brittle materials are distinguished by the relationships between stresses and strains in the materials. Ductile materials can withstand relatively large strains before failure. Objects made of either type of material exhibit elastic deformation in response to initial stresses. When stresses are removed after elastic deformation, the objects return to their initial shapes. [0020] Objects made of ductile materials exhibit plastic deformation in response to stresses greater than an elasticity limit. When stresses are removed after plastic deformation, the objects do not return to their initial shapes. Plastic deformation can result in a large deformation in a ductile material, for example, 15%, before the material fractures. An example ductile material is steel. A material may be considered ductile when it can be deformed more than 5% in plastic deformation. [0021] Objects made of brittle materials do not exhibit large plastic deformations. Objects made of brittle materials abruptly fracture in response to stresses greater than a fracture limit. Example brittle materials include tungsten carbide and silicon carbide. A material may be considered brittle when it can be deformed less than 5% before fracture. [0022] The secondary seal stage 50 includes a portion of the sleeve 5 in the embodiment of FIG. 2 . In other embodiments, the secondary seal stage 50 may include a separate sleeve. The secondary seal stage 50 includes a mating ring 52 disposed in an opening of the sleeve 5 . A sleeve O-ring 53 is disposed in a slot in the opening of the sleeve 5 . The sleeve O-ring 53 provides a static seal between the sleeve 5 and the mating ring 52 . The sleeve O-ring 53 may be made of a polymer, for example, PTFE. [0023] The secondary seal stage 50 also includes a primary ring 51 disposed in an opening of a retainer 54 . The retainer 54 may be formed of a stainless steel. The retainer 54 may be coupled to the housing of a compressor. The primary ring 51 and the mating ring 52 include corresponding opposing faces. [0024] A spring 55 biases the primary ring 51 towards the mating ring 52 . Although one spring is illustrated, the secondary seal stage 50 may have multiple springs circumferentially distributed around the central axis of the seal assembly 142 . The spring 55 may be formed of a superalloy. A spring plate 56 is disposed between the spring 55 and the primary ring 51 . A retainer O-ring 57 is disposed between the spring plate 56 and the retainer 54 and provides a static seal between the spring plate 56 and the retainer 54 . The retainer O-ring 57 may be made of a polymer, for example, PTFE. [0025] The mating ring 52 of the secondary seal stage 50 is made of a ductile material, for example, steel. In an embodiment, the primary ring 51 of the secondary seal stage 50 is also made of a ductile material. The primary ring 51 and the mating ring 52 may be made of the same material or different materials. The primary ring 51 and the mating ring 52 of the secondary seal stage 50 may be strengthened by surface treatment, for example, using induction heating. In another embodiment, the primary ring 51 is made of a more flexible material, such as a carbon composite. INDUSTRIAL APPLICABILITY [0026] The rate that gases leak between the sealing faces of the primary ring 31 and the mating ring 32 is decreased when the faces are closely spaced. The primary ring 31 and the mating ring 32 may be spaced, for example, by a few microns. The components of the seal assembly 142 are subject to shape distortion by thermal changes, gas pressures, and rotational forces. [0027] Prior seal assemblies have used primary and secondary seal stages made of the same materials. Early seal assemblies used mating rings, in both primary and secondary seal stages, made of steel, a ductile material. The seal assemblies used primary rings, in both primary and secondary seal stages, made of a carbon composite material. The carbon composite used is relatively flexible (having a low modulus of elasticity) and low strength compared to the mating ring. The carbon composite is also quite brittle. The carbon composite, because of its low strength, is generally not used as for the mating ring, which rotates. [0028] For use at higher pressures, prior seal assemblies use mating rings, in both primary and secondary seal stages, made of tungsten carbide or silicon carbide, brittle materials. The relatively flexible primary rings conformed against the much stiffer mating rings creating the desired small spacing between the faces of the primary and mating rings. For use at still higher pressures, other prior seal assemblies use mating rings and primary rings, in both primary and secondary seal stages, made of tungsten carbide or silicon carbide. [0029] A seal assembly using a carbide mating ring and a carbon primary ring can fail when the highly stressed mating ring develops cracks due to thermal, rotational, and pressure induced stresses. When the mating ring fails, the carbide material can break up into pieces with jagged edges. With rotation, these pieces can cut into and break up the carbon primary ring causing destruction of the primary ring. [0030] The carbon primary ring is not typically considered the initiator of a failure. If the carbon primary ring were to crack first, since it has low strength, it would not cause another ring to crack and break up. Although the gas flow would increase due to the cracks in the carbon ring, the flow would still be low compare to when pieces of the rings are liberated opening up large flow paths. [0031] A seal assembly using a carbide mating ring and a carbide primary ring can fail in the same manner. Breakup of one of the carbide rings liberates hard pieces which can cause the other carbide ring to fail. [0032] The present seal assembly 142 uses materials in the primary seal stage 30 and the secondary seal stage 50 selected for the distinct functions of the stages. The seal assembly is both very effective at blocking the flow of gases and very rugged. The primary seal stage 30 is effective at blocking flow of gases. The primary seal stage 30 may [add example of seal performance]. The ruggedness of the secondary seal stage 50 can allow it to survive a failure of the primary seal stage. [0033] The materials used in the primary ring 31 and the mating ring 32 of the primary seal stage 30 are selected for their superior performance as a gas seal. For intermediate to high gas pressures at least one of the rings is a rigid material like silicon carbide or tungsten carbide. In some embodiments, both the primary ring 31 and the mating ring 32 are made of these types of materials. Although these materials provide superior seal performance at elevated pressures, in the event of a failure, fracturing and liberation of pieces of these rigid, brittle materials often results in large openings within the seal assembly, which causes excessive amounts of pressurized gas to escape. [0034] The materials used in the primary ring 51 and the mating ring 52 of the secondary seal stage 50 are selected for their ruggedness in the event of a failure of the primary seal stage 30 in addition to performance as a gas seal. The use of a ductile material, like steel, in the highly stressed rotating mating ring 52 mitigates the possibility of pieces of the mating ring 52 being liberated as in the case of a brittle material failure. In various embodiments, the primary ring 51 is made from a ductile material or a carbon material, which is a relatively flexible although somewhat brittle. These materials result in the primary ring remaining more intact and in place after a failure than rings made of the materials used in the primary seal stage. [0035] The disclosed seal assembly embodiments may be suited for any number of industrial applications, such as various aspects of the oil and natural gas industry. For example, applications for compressors with the disclosed seal assemblies may include transmission, gathering, storage, withdrawal, and lifting of oil and natural gas. [0036] The seal assemblies discussed above may be used in servicing a compressor in the field. An existing seal assembly may be removed and replaced with a new seal assembly. The new seal assembly is of a type disclosed above. [0037] The preceding detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. The described embodiments are not limited to use in conjunction with a particular type of compressor. Hence, although the present disclosure, for convenience of explanation, depicts and describes a seal assembly for a centrifugal compressor, it will be appreciated that seal assemblies in accordance with this disclosure can be implemented in various other configurations and used in other types of machines. Furthermore, there is no intention to be bound by any theory presented in the preceding background or detailed description. It is also understood that the illustrations may include exaggerated dimensions to better illustrate the referenced items shown, and are not consider limiting unless expressly stated as such.

A seal assembly forms a barrier between a compressor's interior and exterior regions. The seals assembly includes a primary seal stage and a secondary seal stage. The primary seal stage is formed of materials chosen to effectively block flow of gas through the seal assembly. The secondary seal stage is formed of materials chosen to survive a failure of the primary seal stage.

RELATED PATENT DATA [0001] This patent resulted from a divisional application of U.S. patent application Ser. No. 11/745,843, which claims priority under 35 U.S.C. § 119 to U.S. Provisional Application No. 60/747,606, which was filed May 18, 2006; and to U.S. Provisional Application No. 60/842,194, which was filed Aug. 31, 2006, and claims priority to U.S. Provisional Application No. 60/895,621, which was filed Mar. 19, 2007. TECHNICAL FIELD [0002] The invention pertains to intravascular port access devices, intravascular port cleaning devices, methods of cleaning an intravascular port, methods of administering an agent into an intravascular line port, methods of obtaining a blood sample from an individual, and sets of intravascular line port caps. BACKGROUND OF THE INVENTION [0003] Intravenous lines, such as peripheral IV lines and central IV lines, are common intravenous access methods for administering medicants, nutrient solutions, blood products, or other substances into a vein. Arterial lines are used, for example, in monitoring physiological parameters by arterial blood sampling during coronary, intensive or critical care. However, microorganism intravascular device colonization or infection can occur as a result from a patients' own endogenous flora or from microorganisms introduced from contaminated equipment or other environmental contamination sources. As a result, localized or systemic infection or septicemia can occur and can be life threatening. [0004] Introduction of microorganisms into an intravenous line can be initiated or facilitated during handling of a catheter, hub, associated tubing, equipment, or injection ports, especially during manipulation of lines in preparation and during initiation of fluid administration into or withdrawal from the line. Microorganisms present on a surface of an injection port can be introduced through the port during administration. Microorganisms present on contaminated equipment utilized for administration can be introduced through the port causing colonization or infection. Bacterial growth and/or aggregation in a port or catheter can serve as the nidus for clotting, embolization and/or occlusion of the port or catheter. Further manipulation or administration through the port can facilitate spreading of microorganisms within the port, catheter, and lines, and ultimately into the patient's vein/artery and/or surrounding tissue. Accordingly, it would be advantageous to develop methods and devices for cleaning of external surfaces of intravascular access ports and/or internal port areas to reduce risks of colonization and infection. [0005] Another complication that can occur in association with an intravascular line, catheter or access port is clot formation due to blood return. Initial clot formation could extend and/or embolize into the superior vena cava and/or the right atrium and/or right ventricle of the heart, and subsequently into the pulmonary system circulating to the lungs. It would be advantageous to develop methodology and devices to deliver clot dissolving or clot inhibitory agents through intravascular ports to minimize or eliminate intravascular port associated clotting. [0006] Yet another issue that can be associated with intravascular lines is lipid accumulation or build-up within the line or port. It would be advantageous to develop methodology and devices to deliver lipolytic agents through intravascular ports to minimize or eliminate port associated lipid build up. SUMMARY OF THE INVENTION [0007] In one aspect the invention pertains to an intravascular port access device. The device includes a first component having a chamber and being configured to attach reversibly to an intravenous line port. The second component reversibly attaches to the first component and contains a disinfecting agent and an applicator material selected from the group consisting of polyethylene felt sponge, polyethylene foam sponge, plastic foam sponge and silicon foam sponge. The second component is configured to be reversibly received over external surfaces of the intravenous line port. [0008] In one aspect the invention encompasses an intravascular line port cleaner including a syringe barrel having a first end and a second end. A slideable piston is received into the barrel through the second end. The line port cleaner includes a first cap containing a cleansing agent and a second cap containing a microbiocidal agent. [0009] In one aspect the invention encompasses a method of cleansing an intravenous line port. The method includes providing a port cleaning device comprising a first component having a chamber with a first cleaning agent. A second component includes a second cleaning agent. A third component has a microbiocidal agent and is reversibly attached to the first component. The method includes removing a second component from the device, contacting the external surfaces of the port with the second cleaning agent, injecting the first cleaning agent from the chamber into the port, removing the third component from the device, and capping the port with the third component. [0010] In one aspect the invention encompasses a method of obtaining a blood sample from an individual. The method includes providing a port access device having a first component including a chamber, a second component containing a cleaning agent and a third component comprising a microbiocidal agent. The third component is reversibly attached to the first component. The method includes removing the second component from the device and contacting the external surfaces of the port with the cleaning agent. The method further includes drawing blood from the individual through the port into the chamber of the first component removing the third component from the device and capping the port with the third component. [0011] In one aspect the invention includes a set of intravascular line port caps. The set of caps includes a first port cap containing a first agent and a first applicator material. The set further includes a second port cap containing a second agent and a second applicator material. BRIEF DESCRIPTION OF THE DRAWINGS [0012] Preferred embodiments of the invention are described below with reference to the following accompanying drawings. [0013] FIG. 1 is a diagrammatic isometric view of a device in accordance with one aspect of the invention. [0014] FIG. 2 is a diagrammatic side view of the device shown in FIG. 1 . [0015] FIG. 3 is a diagrammatic exploded view of the device shown in FIG. 1 . [0016] FIG. 4 is a diagrammatic cross-sectional view of the device shown in FIG. 1 . [0017] FIG. 5 is a diagrammatic cross-sectional view of the device shown in FIG. 1 after repositioning relative to the positioning depicted in FIG. 4 . [0018] FIG. 6 is a diagrammatic isometric view of a device in accordance with another aspect of the invention. [0019] FIG. 7 is a diagrammatic side view of the device shown in FIG. 6 . [0020] FIG. 8 is a diagrammatic exploded view of the device of FIG. 6 . [0021] FIG. 9 is a diagrammatic cross-sectional view of the device shown in FIG. 6 . [0022] FIG. 10 is a diagrammatic view of an exemplary packaging concept for the device shown in FIG. 6 . [0023] FIG. 11 shows a multi-pack packaging concept for the device shown in FIG. 6 . [0024] FIG. 12 is a diagrammatic exploded view of a device in accordance with another aspect of the invention. [0025] FIG. 13 is a diagrammatic cross-sectional view of the device shown in FIG. 12 . [0026] FIG. 14 is a diagrammatic exploded view of a device in accordance with another aspect of the invention. [0027] FIG. 15 is a diagrammatic exploded view of a device in accordance with another aspect of the invention. [0028] FIG. 16 is a diagrammatic cross-sectional side view of the device shown in FIG. 15 . [0029] FIG. 17 is a diagrammatic isometric view of a packaging concept in accordance with one aspect of the invention. [0030] FIG. 18 is a diagrammatic isometric view of the packaging concept shown in FIG. 17 . [0031] FIG. 19 is another diagrammatic isometric view of the packaging concept shown in FIG. 17 . [0032] FIG. 20 is a diagrammatic isometric view of a set of components in accordance with one aspect of the invention. [0033] FIG. 21 is an exploded view of the set of components depicted in FIG. 20 . [0034] FIG. 22 is a diagrammatic exploded view of a packaging concept in accordance with one aspect of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0035] This disclosure of the invention is submitted in furtherance of the constitutional purposes of the U.S. Patent Laws “to promote the progress of science and useful arts” (Article 1, Section 8). [0036] In general the invention includes devices and methodology for cleaning and/or accessing intravascular line ports. In particular applications devices of the invention can be used for cleaning external surfaces of a intravascular line port followed by cleaning of the port itself and in particular instances cleaning of intravascular lines. [0037] In other applications devices of the invention can be utilized for administering an agent intravascularly. During these applications, the devices in accordance with the invention can typically be utilized to cleanse external surfaces of the port prior to utilizing the device for administering of an agent intravascularly. In another application devices of the invention can be utilized to obtain a blood sample from an individual. A device in accordance with the invention is typically utilized to cleanse external surfaces of a port prior to utilizing the device to withdraw a sample of blood from the port. The invention also includes methodology for such port cleansing agent administration and blood sampling techniques. [0038] In one embodiment, the device comprises two components. An example two component device is described with reference to FIGS. 1-5 . [0039] Referring initially to FIG. 1 , a port access device 10 comprises a first component 12 at a first end 14 of the device, and a second component 16 at a second end 18 of the device. Second component 16 can have a tab 20 or other extension feature for assisting removal of the second component from the first component. First component 12 has a chamber housing 22 which can be a collapsible housing. First component 12 can also comprise an extension portion 24 . Referring to FIG. 2 , as depicted device 10 can have second portion 16 insertable within connector portion 24 . It is to be understood however that the invention contemplates other configurations wherein second portion 16 fits over or caps extension portion 24 . It is also to be understood that the shape and dimension of collapsible housing 22 is but an example with alternative shapes, sizes and configurations contemplated. [0040] Referring to FIG. 3 such shows an exploded view of the device depicted in FIGS. 1 and 2 . As illustrated chamber housing 22 of device 10 can house a chamber 23 . Connector 24 can comprise a separator 25 having an opening 29 passing therethrough. Connector 24 can further comprise a receiving port 30 for receiving a dispenser 26 . Dispenser 26 in turn can comprise a valve portion 28 . Second component 16 can comprise a container 21 . [0041] Referring next to FIG. 4 , such shows dispenser 26 with valve 28 seated within receiving port 30 . As depicted such valve mechanism is in the “closed” position where contents of chamber 23 are blocked from passing into or through connector 24 . Referring next to FIG. 5 , application of force upon collapsible housing 22 such as a downward pressure upon a top surface of the housing can be utilized to displace valve device 28 from receiving port 30 as illustrated. Such displacement can allow passage of the contents of chamber 23 into or through connector portion 24 . [0042] As depicted in FIG. 4 , second component 16 can contain an applicator material 32 . Such applicator material can be for example, a sponge or sponge-type material. Exemplary sponge-type materials can include but are not limited to polyethylene felt sponge, polyethylene foam sponge, plastic foam sponge and silicon foam sponge. [0043] Where device 10 is to be utilized for port cleansing applications, container 21 of second component 16 will typically contain a cleansing agent. The cleansing agent can be a disinfecting agent for cleansing external port surfaces. The agent is not limited to a particular cleaning or disinfecting agent and can comprise for example alcohol, preferably contained in an alcohol solution comprising from about 5% to about 99% alcohol. In particular applications the alcohol solution will comprise 25% to 90% alcohol. The sponge-type applicator material can be utilized to assist in containing the cleansing agent and can further assist in applying the agent to external surfaces of the intravascular port. Second component 16 is removably attached to the device 10 . For cleansing of the port, removable component 16 is removed from first component 12 and is utilized to contact external port surfaces for cleansing of external portions of an intravascular line port. [0044] After cleansing of external portions of the port, the first component of the device, which in cleansing/disinfecting applications can be utilized for internal cleansing of the intravascular port, can be reversibly attached to the port to be cleansed. The chamber volume can be for example up to 3.5 ml; a preferred volume range can be from about 1 to about 3 ml. although alternative chamber sizes for smaller or larger volumes are contemplated. The chamber can have appropriate calibration marks relative to the total volume of the chamber. For example, a 3.5 ml. fluid volume chamber can have volume markings every 1 ml, every 0.5 ml, every 0.1 ml, etc. In particular embodiments, the connector portion can have a LEUR-LOK® (Becton, Dickinson and Company Corp., Franklin Lakes N.J.) fitting (not shown) for connection to a LEUR-LOK® type port. A cleansing agent can be provided within chamber 23 and can be an antibiotic or an alternative appropriate disinfectant. An exemplary agent can be an alcohol or alcohol solution such as described above relative to the second component container 21 . In cleansing applications chamber 22 can alternatively or additionally contain chemical agents including ethylene diamine tretaacetic acid (EDTA) and/or sodium citrate. [0045] Once connected to the line port external pressure can be applied to collapsible housing 22 by for example squeezing, pinching, or pushing inward on the housing to displace dispenser 26 thereby opening or displacing valve 28 from receiving port 30 . Continued squeezing or external force can be utilized to dispel or eject contents of chamber 23 through connector 24 and into the connected port. Depending upon the volume of chamber 23 the injected cleansing solution may extend into the intravascular line itself. After dispelling the contents of chamber 23 device component 12 can be removed from the port to allow administration of fluids to be delivered intravascularly (for example). If such delivery is not to be performed immediately upon cleansing, component 12 of the cleansing device can be retained on the port until such time as intravascular delivery is desired. [0046] In another aspect, the above-described device and methodology can be utilized for administering an anti-clot agent to minimize or prevent intravascular associated clot formation or to dissolve an existing clot. In this aspect, rather than or in addition to the antimicrobial agent, chamber 23 can contain an appropriate anticoagulant agent or clot dissolving agent. Exemplary anti-clot agents which can be utilized include but are not limited to anticoagulants such as EDTA, sodium citrate, heparin and heparin derivatives, and anti-thrombolytic agents such as tissue plasminogen activator. Where lipid accumulation is an issue an appropriate dispersion or lipolytic agent can be administered, either independently or in combination with antimicrobial agent and/or anti-clot agent. Injection of any such agents can be achieved in a manner analogous to that described above relative to the cleansing agent. These applications may also be accomplished utilizing the embodiments illustrated and described below. [0047] An alternative embodiment of a device in accordance with the invention is illustrated and described with reference to FIGS. 6-11 . Referring to FIG. 6 , such illustrates an alternative example port access device 40 having a syringe-like first component 42 and a second component 44 . Referring to FIG. 7 syringe-like first component 42 includes a plunger 46 . An exploded view of the port access device is depicted in FIG. 8 . First component 42 includes a syringe barrel-like housing 48 having a first end 50 and a second end 52 with an internal chamber 54 . Chamber 54 can preferably have a fluid volume of from 1 to about 3.5 ml. Housing 48 can have appropriate calibration marks as discussed above with respect to the earlier embodiment. [0048] Plunger 46 can include a stem portion 56 having a seal 57 . Plunger 46 can be insertable into second end 52 of housing 48 . A second seal 59 can be associated with the larger diameter body of the plunger. Seal 59 is preferably present to form a seal between the plunger and an internal surface of the device chamber. Seal 59 can preferably be an elastameric seal which is over molded onto the piston (which can preferably be a molded hard plastic material). However, the invention contemplates alternative seal material and use of non-overmolded techniques. [0049] Seal 57 can be a single seal or a set of seals and can be for example a set of two o-rings, a single broad overmolded elastameric o-ring or sleeve or a hard plastic seal molded integrally with the piston stem. The presence of seal 57 can advantageously inhibit or prevent unwanted or unintentional backflow of fluid into the device chamber thereby decreasing the risk of contamination of the device and/or its contents. Alternatively relative to the depicted configuration a single seal can be over molded to have a base portion which forms the seal between an internal wall of the device chamber and the large diameter portion of the piston and a sleeve portion which covers the walls of the smaller diameter portion of the piston (not shown). [0050] The second component 44 is a removable cap portion having a housing 60 and an internal container 62 . Container 62 can contain an applicator material 64 . The applicator material can be, for example, any of those materials discussed above with respect to the earlier embodiment. The second component 44 can additionally contain a cleansing agent such as those cleansing agents discussed above. Second component 44 preferably can be configured to fit over or onto an intravascular port such that the cleansing agent can be applied to external surfaces of the port. Such cleaning preferably can be conducted prior to administering the contents of chamber 54 (for example, an anti-clot, antimicrobial or other cleansing agent) into the port. However, the invention contemplates post-administration cleansing of the port utilizing the removable cap portion. [0051] Referring next to FIG. 9 , such shows a cross-sectional view of the embodied device 40 in an intact configuration. For utilization second component 44 can be removed and utilized to cleanse external surface of the port. Subsequently, first end 50 of the second component can be attached to the port and contents of the chamber 54 can be administered into the port by application of force to plunger 46 . Alternatively, chamber 54 can be provided empty or can be provided to contain, for example, an anticoagulant agent and device 40 can be provided with plunger 46 in a forward position. Thus device 40 can be utilized for applications such as obtaining and/or testing of a blood sample from an individual by attaching first end 50 of the device to the port and repositioning of plunger 46 to draw fluid through the port into chamber 54 . [0052] Referring to FIG. 10 packaging 70 for delivery, storage and/or disposal of the component for access device 40 is illustrated. Such packaging includes a lid 72 and a tray portion 74 . Tray portion 74 has a cavity 76 with molded retainers 78 for positioning/retaining of the device and assisting in maintaining the integrity of the device and proper positioning of the plunger relative to the device chamber. Such packaging can be sealed and can be utilized to provide a sterile environment for device 40 . As shown in FIG. 11 a series 71 of individual packaging unit 70 can be provided with individually sealed units to allow individual removal of units while maintaining sterility of additional units in the series. [0053] Another alternative embodiment is described with reference to FIGS. 12-13 . In this embodiment first component 42 a is the same as the immediately preceding embodiment. However, referring to FIG. 12 second component 44 a comprises a “dual cap” system. Cap housing 60 a includes container portion 62 and a second cap extension 65 which houses a second container 66 . Container 62 can contain an applicator material 64 such as the sponge-like materials described above. Similarly container 66 can also contain a sponge or other applicator material 67 . Container 62 can further contain a cleansing agent such as those described above. [0054] Container 66 can preferably contain one or more microbiocidal agents that differ in composition from the cleaning solution contained in the cleansing cap 62 . An example agent composition within cap portion 65 can include from about 3% to about 11% H 2 O 2 . Additional components of the agent can include for example ethanol (from about 30% to about 40%) sodium citrate (from about 1% to about 4%), EDTA, and/or peracetic acid (less than or equal to about 11%). Preferably, the pH will be between 5 and 10 and can be adjusted with NaOH or other appropriate base/acid to about ph 7.4 as needed based upon the physiological pH and biocidal activity. The presence of EDTA can provide sporocidal activity against for example bacillus spores by complexing Mn and can additionally help stabilize H 2 O 2 . In combination with H 2 O 2 in the solution a synergistic and/or additive effect can be achieved. The invention does contemplate use of alternative chelators and pH stabilizers relative to those indicated. [0055] It is to be noted that in some instances a similar solution having lower peroxide content may be included within the first container 62 and in particular instances may be present within the chamber of the first component. [0056] Referring to FIG. 13 such shows an intact device prior to use. In port cleansing applications second component 44 a is removed from the device and portion 60 a is utilized to cover a port thereby contacting the port with the contents of container 62 . Applicator material 64 can assist in applying the cleaning agent to external port surfaces. When the contents of chamber 54 are to be administered, component 44 a is removed from the port and first component is attached to the port. Plunger 46 is depressed thereby injecting the contents of chamber 54 into the port. The syringe component is then removed from the port. A removable seal 68 can then be removed from second cap portion 65 . Cap portion 65 can be placed over the port such that the contents of container 66 contact the port. Second component 44 can then be removed from the port or can be retained on the port until further port access or manipulation is desired. [0057] Referring to FIG. 14 such shows an alternative embodiment wherein port access device 40 b comprises a first component 42 b , a second component 44 b and a third component 45 b where second component 44 b and third component 45 b are independently removable caps. As illustrated the caps are disposed initially at opposing ends of the device and are of differing size. However, alternative relative size and positioning of the caps on the device is contemplated. For example, first component 44 b and second 45 b can be disposed on top-side or bottom-side of wing extensions 51 , 53 of chamber housing 48 b. [0058] For the example configuration illustrated, the larger cap (first component 44 b ) can be removed from the device and can be utilized for external port cleaning in a manner analogous to that described above. The second smaller cap (third component 45 b ) can be removed from the device after administration of the chamber contents and can be subsequently utilized as a port cap to protect the port until subsequent port access is desired as described above. Third component 45 b optionally can contain an applicator material 82 and/or cleansing agent or microbiocidal agent as described above. [0059] Alternative two-cap configurations include a device having a larger cap external to a smaller internal cap, the first cap being removable from the second cap where one of the first and second caps is configured for utilization as a port cap. [0060] In the device shown in FIG. 14 , cap housing 60 b of second component 44 b and cap housing 80 of third component 45 b can be of differing colors. As such, the caps can be color coded (or otherwise coded) to notify the user or other personnel of the status of the port or intravascular line. For example, a first color such as green can be utilized on all or a portion of cap housing 80 which will be retained on the port after use of the device to signify a properly sterilized port. Cap housing 60 b can be a second color (e.g., yellow or red) signifying the cleansing or other procedure being performed has not yet been completed. Accordingly, the caps can be utilized as an added safety measure to help ensure proper use and assist in maintaining sterility and appropriate record keeping. For example, the caps can allow visual monitoring and can be tracked by hospital pharmacy and/or central auditing software. [0061] In addition to visual auditing of compliance to proper cleaning and maintenance of sterility, a barcode, radio frequency identification (RFID) and/or other pharmacy dispensary or inventory control system associated with the device can be utilized to provide an independent audit/compliance system. [0062] Referring next to FIG. 15 such depicts an additional alternate embodiment which can utilize a conventional type syringe and plunger design and can utilize caps in accordance with the invention. Accordingly, first component 42 c comprises a syringe housing 48 c and can have a LEUR-LOK® fitting at first end 50 . Plunger 46 c can have a conventional type piston seal 57 c configured to insert into second end 52 of housing 48 c and form a seal with the walls of chamber 54 c . Second component 44 c can comprise a housing 60 c which can for example have an internal receiving port which fits either internally relative to the LEUR-LOK® fitting or which fits over and covers the LEUR-LOK® fitting at first end 50 of first component housing 48 c . Third component 45 c can also have housing 80 c configured such that it comprises an internal receiving port which fits either internally relative to a LEUR-LOK® fitting or which fits over and covers the LEUR-LOK® fitting (or which can have an alternative type fitting) based upon the type of port being cleansed. [0063] A cross-sectional view of the device shown in FIG. 15 is illustrated in FIG. 16 . Such shows the exemplary type of cap housings for covering LEUR-LOK®-type fittings. For example third component 45 c has housing 80 c comprising a portion of such housing which fits internally within a LEUR-LOK® type fitting thereby capping such fitting. In contrast second component 44 c has housing 60 c which is threaded to thread onto LEUR-LOK® type fitting. It is to be understood that the depiction is for illustrative purposes only and that either or both caps can have the threaded configuration or the snap in configuration. Cap housing 60 c and 80 c can further be color coded as described above. [0064] The invention also contemplates dual cap system disposed at the distal (non-administration) end of the port cleaner device (not shown). In this dual cap system a first “green” cap can be reversibly joined to both the device and also back to front in a stack relationship relative to a second “yellow” cap. Each of the two caps can be, for example, a LEUR-LOK® type fitting cap, friction fit cap, etc. The green cap can contain the microbiocide composition described above. The yellow cap can contain for example the cleaning compositions discussed earlier or the microbiocide composition as contained in the green cap since in this configuration the yellow cap is not in contact with the administration end of the device. [0065] Possible materials for caps include, but are not limited to, polyethylene, polypropylene, and/or copolymer materials. Further, the caps can preferably comprise a material or agent that is UV protective to preserve the integrity of hydrogen peroxide during storage, shipping, etc. Packaging may also contain UV protective materials to inhibit peroxide breakdown. [0066] As mentioned above, devices of the invention can be utilized for withdrawing blood from an individual through an intravascular catheter or intravascular port. In particular applications, the device can be utilized directly for blood testing purposes. The device chamber can preferably have a chamber size in the range of 1 to 3 ml, with appropriate calibration marks as discussed above. Where whole blood is desired, depending upon the particular purpose for drawing, blood can be drawn into either a device having an empty chamber or into a device containing an anticoagulant such as EDTA, sodium citrate or alternative coagulant (such as discussed above). The device containing blood and anticoagulant can then be utilized directly in blood testing equipment or blood can be transferred to an alternative device for testing. [0067] In applications where serum is desired, whole blood can be drawn into the device chamber and, after coagulation, the device containing the blood sample can be spun to separate the serum from the red blood cells. If anticoagulant is present in the device chamber, further separation can occur to isolate plasma. Alternatively, a filter such as a MILLIPORE® (Millipore Corp., Bedford Mass.) filter can be fitted onto the device after a sample is drawn into the device chamber. Such technique can filter out red blood cells, white blood cells and platelets allowing serum to flow from the chamber while retaining the blood cells within the filter. Anticoagulants can optionally be provided within the chamber to allow transfer of blood cells or plasma if such is desired based upon the testing or other procedure to be performed (i.e., complete blood count, CBC, platelet count, reticulocyte count, T and B lymphocyte assays and chemistries). [0068] An appropriate filter can also be utilized to filter out particulates during drawing of a blood sample from an individual into the chamber. [0069] It is to be understood that any of the devices above can be utilized for cleansing purposes, for administration purposes or for blood drawing/testing purposes. Methodology will be analogous with variation based upon the particular device utilized as described above. [0070] Example device packaging is illustrated in FIGS. 17-19 . Packaging 100 can include a lid portion 102 and a packaging tray 104 as shown in FIG. 17 . Referring to FIGS. 18 and 19 packaging tray 104 can be a molded tray which has integrally molded retaining features which conform to the shape of a device 40 c in accordance with the invention. Preferably the molded features conform to the shape of the device in the non-deployed position for shipment, storage, etc. Accordingly tray 104 can have one or more integrally molded retainer features 106 , 107 , 108 and 109 . Tray 104 can also comprise an integrally molded receiving stand 110 which can be configured to receive device 40 c in an upright position as depicted in FIG. 18 . Such receiving stand can allow device 40 c to be inserted and retained during administrative procedures or after use. Tray 104 may also be used for device disposal purposes. [0071] Device caps in accordance with the invention can be utilized independent of the devices for cleansing and protection of alternative access catheters and ports such as intravascular, peritoneal dialysis, urinary ports and catheters, etc. Accordingly, the caps can be packaged independently in pairs (one each of two differing sizes, colors, etc., in groups or in bulk, of one or more colors). FIGS. 20-21 show an example two cap packaging system 115 having a first cap 117 which can be for example a yellow cap and which can preferably be a LEUR-LOK® type cap and a second cap 118 which can be, for example, a green cap and which can also be a LEUR-LOK®. Packaging system 115 can comprise a packaging tray 120 and as illustrated in FIG. 21 can include integrally molded appropriate receiving ports/receiving rings 122 , 124 . Where additional or fewer caps are to be packaged together tray 120 can have an appropriate number of receiving ports for receiving and reversibly retaining the caps. Where the caps differ in size (diametric), the ports can also be of differing size as appropriate. It is to be understood that the caps may be provided in groups such as one green and four yellow caps per package or any other appropriate number depending upon the particular procedure for which they will be utilized with the number and size of package ports corresponding to the number and size of various caps. [0072] Referring next to FIG. 22 an alternative packaging system 130 is illustrated. Packaging system 130 comprises a lid 132 and a tray 130 having integral receiving ports 136 and 138 for receiving caps 117 and 118 . As discussed above alternative numbers and sizes of receiving ports can be provided based upon the number and sizes of caps to be utilized. [0073] Where caps are provided in bulk, such may be individually packaged and may be provided individually in sheets or on strips. Caps can alternatively be provided with catheter or line/import devices. Such can be included in common packaging either loose or attached to a port catheter or line to be used for port cleaning and/or protection after package opening and/or while the device is in use. In some instances the cap(s) can be packaged in one or more sub-packages included within a larger package enclosing the catheter device. [0074] In compliance with the statute, the invention has been described in language more or less specific as to structural and methodical features. It is to be understood, however, that the invention is not limited to the specific features shown and described, since the means herein disclosed comprise preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted in accordance with the doctrine of equivalents.

An intravascular port access device includes a first component having a chamber configured to attach reversibly to an intravenous line port. A second component reversibly attaches to the first component and contains a disinfecting agent and an applicator material. The second component is configured to be reversibly received over external surfaces of the intravenous line port. A method of cleansing an intravenous line port includes providing a port cleaning device having a first component with a chamber containing a first cleaning agent. A second component includes a second cleaning agent. A third component has a microbiocidal agent and is reversibly attached to the first component. The second component is removed from the device, the external surfaces of the port are contacted with the second cleaning agent, the first cleaning agent is ejected from the chamber into the port, and the third component is used to cap the port.

RELATED APPLICATIONS This application claims priority under 35 U.S.C. §119 to Japanese Patent Application No. 2010-079195 filed on Mar. 30, 2010, the entire content of which is hereby incorporated by reference. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sample processing apparatus, a sample transporting method, and a non-transitory storage medium for transporting a sample to a testing unit. 2. Description of the Related Art In Japanese Laid-Open Patent Publication No. 2002-318237, there is a description of a sample rack transport system which includes a transport apparatus in which a plurality of line units are connected in series, a supply section supplying a sample rack to the transport apparatus, and a controller for storing information relating to a processing status of the sample rack and controlling the transport apparatus. In this sample rack transport system, a transport line for transporting a sample rack and a return line for returning a sample rack to the upstream side of the transport line are configured by connecting the plurality of line units and sample racks can be transported to sample processing units corresponding to the respective line units via the transport line. If trouble occurs during the transport of a sample rack in this sample rack transport system, after the system is restored from the trouble, the controller performs controls the transport apparatus so as to supply a sample rack to a sample processing unit which is to be the next transport destination on the basis information relating to the rack processing status. However, in the above-described sample rack transport system, when trouble occurs during the transport of a sample rack, the transport operation of the sample rack by the sample rack transport system is completely stopped until the trouble is resolved. SUMMARY OF THE INVENTION The scope of the present invention is defined solely by the appended claims, and is not affected to any degree by the statements within this summary. According to a first aspect of the present invention, a sample processing apparatus comprising: a plurality of testing units arranged along a transport path and each configured to perform at least one type of test; a plurality of transport units configured to collectively constitute the transport path and collectively function to deliver samples to the plurality of testing units for testing; and at least one processor of a computer system and at least one memory that stores programs executable by the at least one processor to: (a) determine a type of test required to be performed on a sample; (b) if a trouble of a transport unit is reported, determine whether there is an available testing unit performable of the required type of test to which the sample is deliverable; (c) if there is the available testing unit, instruct to transport the sample to the available testing unit. According to a second aspect of the present invention, a sample transporting method executed in a sample processing apparatus comprising a plurality of testing units arranged along a transport path and each configured to perform at least one type of test and a plurality of transport units configured to collectively constitute the transport path and collectively function to deliver samples to the plurality of testing units for testing, the method comprising computer-executable steps executed by at least one processor of a computer system to implement: (a) determining a type of test required to be performed on a sample; (b) if a trouble of a transport unit is reported, determining whether there is an available testing unit performable of the required type of test to which the sample is deliverable; (c) if there is the available testing unit, instructing to transport the sample to the available testing unit. According to a third aspect of the present invention, a non-transitory storage medium provided in a sample processing apparatus which comprises a plurality of testing units arranged along a transport path and each configured to perform at least one type of test and a plurality of transport units configured to collectively constitute the transport path and collectively function to deliver samples to the plurality of testing units for testing, the storage medium storing programs executed by at least one processor of a computer system to: (a) determine a type of test required to be performed on a sample; (b) if a trouble of a transport unit is reported, determine whether there is an available testing unit performable of the required type of test to which the sample is deliverable; (c) if there is the available testing unit, instruct to transport the sample to the available testing unit. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic plan view showing the overall configuration of a sample processing apparatus according to a first embodiment. FIG. 2 is a plan view showing the configuration of a sample insertion and recovery apparatus according to the first embodiment. FIG. 3 is a perspective view showing the appearance of a sample container. FIG. 4 is a perspective view showing the appearance of a sample rack. FIG. 5 is a plan view showing the configuration of a sample transport apparatus for a blood cell analysis apparatus according to the first embodiment. FIG. 6 is a plan view showing the configuration of a sample transport apparatus for a smear preparation apparatus according to the first embodiment. FIG. 7 is a block diagram showing the configuration of a measuring unit of the blood cell analysis apparatus according to the first embodiment. FIG. 8 is a block diagram showing the configuration of an information processing unit of the blood cell analysis apparatus according to the first embodiment. FIG. 9 is a block diagram showing the configuration of a system control apparatus according to the first embodiment. FIG. 10 is a flowchart showing the flow of a sample discharge operation of the sample insertion and recovery apparatus according to the first embodiment. FIG. 11 is a flowchart showing the flow of a measurement order obtaining operation of the system control apparatus according to the first embodiment. FIG. 12 is a flowchart showing the flow of a first transport instruction operation of the system control apparatus according to the first embodiment. FIG. 13 is a flowchart showing the flow of a first transport operation of the sample transport apparatus for the blood cell analysis apparatus according to the first embodiment. FIG. 14 is a flowchart showing the flow of a transport destination change process when trouble occurs in the system control apparatus according to the first embodiment. FIG. 15 is a flowchart showing the flow of a rack transport control operation of the blood cell analysis apparatus according to the first embodiment. FIG. 16 is a flowchart showing the flow of a sample analysis operation of the blood cell analysis apparatus according to the first embodiment. FIG. 17 is a flowchart showing the flow of a second transport instruction operation of the system control apparatus according to the first embodiment. FIG. 18 is a flowchart showing the flow of a second transport operation of the sample transport apparatus according to the first embodiment. FIG. 19 is a flowchart showing the flow of a rack sorting and recovery operation of the sample insertion and recovery apparatus according to the first embodiment. FIG. 20 is a plan view showing the configuration of a sample insertion and recovery apparatus according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings. (First Embodiment) This embodiment is a sample rack transport system which includes an insertion apparatus for inserting sample racks containing a plurality of samples, a sample transport apparatus transporting an inserted sample rack and supplying the sample rack to a measuring apparatus and a plurality of recovery apparatuses recovering sample racks to sort and recover sample racks into the plurality of recovery apparatuses in accordance with whether all the measurement items based on a measurement order are measured when trouble (abnormality) occurs. Here, in this embodiment, the trouble is not a small problem such as a mistake in the transport of sample racks, but is a severe problem which requires repair by a service man due to a physical breakdown of the transport mechanism of the sample transport apparatus. FIG. 1 is a schematic plan view showing the overall configuration of a sample processing system 1 including the sample rack transport system according to this embodiment. As shown in FIG. 1 , the sample rack transport system 100 includes a sample insertion and recovery apparatus 2 , sample transport apparatuses 3 a , 3 b , 3 c and 4 and a system control apparatus 8 . In addition, the sample processing system 1 includes a sample rack transport system 100 , a blood cell analysis apparatus 5 and a smear preparation apparatus 6 . In addition, the sample processing system 1 according to this embodiment is connected to an examination information management apparatus 9 so as to communicate therewith via a communication network. <Configuration of Sample Insertion and Recovery Apparatus 2 > FIG. 2 is a plan view showing the configuration of the sample insertion and recovery apparatus 2 according to this embodiment. The sample insertion and recovery apparatus 2 includes a sample insertion unit 21 , a pre-processing unit 22 and sample recovery units (rack recovery section) 23 and 24 . In the sample insertion and recovery apparatus 2 , sample racks can be placed which accommodate a plurality of sample containers. Such a sample insertion and recovery apparatus 2 has a sample insertion unit group 2 A including the sample insertion unit 21 and the pre-processing unit 22 and a sample recovery unit group 2 B including the sample recovery units 23 and 24 . FIG. 3 is a perspective view showing the appearance of a sample container T and FIG. 4 is a perspective view showing the appearance of a sample rack L. As shown in FIG. 3 , the sample container T has a tubular shape and the upper end thereof is opened. A blood sample collected from a patient is contained in the sample container and the opening at the upper end is sealed by a cap section CP. The sample container T is made of glass or a synthetic resin having translucency and the blood sample therein can be visually confirmed. In addition, a barcode label BL 1 is adhered to the side surface of the sample container T. A barcode (sample barcode) showing a sample ID is printed on this barcode label BL 1 . In the sample rack L, 10 sample containers T can be arranged in parallel and held. In the sample rack L, sample containers T are held in a vertical state (erect state). In addition, a barcode label BL 2 is adhered to the side surface of the sample rack L. A barcode (rack barcode) showing a rack ID is printed on this barcode label BL 2 . As shown in FIG. 2 , the sample insertion unit 21 has a concave-shaped rack placement section 211 for placing a sample rack L accommodating sample containers T. This rack placement section 211 has a rectangular shape and a plurality of sample racks L can be placed at the same time therein. Sample racks L are placed in the rack placement section 211 so that sample containers T are arranged in parallel in the transverse direction. The rack placement section 211 is provided with sensors 212 and 213 for detecting a sample rack L and engagement sections 211 a for transferring a sample rack L. The sensors 212 and 213 are optical sensors. The sensor 212 includes a light-emitting section 212 a and a light-receiving section 212 b , and the sensor 213 includes a light-emitting section 213 a and a light-receiving section 213 b . The light-emitting section 212 a is disposed on the front-left side of the rack placement section 211 and the light-receiving section 212 b is disposed on the central-right side of the rack placement section 211 . In addition, the light-emitting section 213 a is disposed on the rear-left side of the rack placement section 211 and the light-receiving section 213 b is disposed on the central-right side of the rack placement section 211 . The light-emitting section 212 a is disposed so as to emit light in the diagonally backward right direction and the light-receiving section 212 b is disposed so as to receive this light across the rack placement section 211 . The light-emitting section 213 a is disposed so as to emit light in the diagonally forward right direction and the light-receiving section 213 b is disposed so as to emit this light across the rack placement section 211 . Accordingly, the light emitted from the light-emitting section 212 a or 213 a is shielded by a sample rack L placed in the rack placement section 211 and the sample rack L is detected by the rack sensor 212 or 213 due to a lowering of the light-reception level of the light-receiving section 212 b or 213 b . The sample rack L detected by the rack sensor 212 or 213 engages with the engagement sections 211 a and moves forward and backward while the engagement sections 211 a engage with the sample rack L. Therefore, the sample rack L is transferred on the rack placement section 211 . The position on the innermost side of the rack placement section 211 serves as a rack output position 214 for outputting a sample rack L to the left side. Such a rack output position 214 is provided with a protrusion section 215 which is movable left- and rightward. This protrusion section 215 waits at the position near the right end of the rack output position 214 until a sample rack L is transferred to the rack output position 214 . When the sample rack L reaches the rack output position 214 , the protrusion section moves leftward. The sample rack L is pushed by the protrusion section 215 and moves leftward. In addition, the walls on the both right and left sides of the rack output position 214 are missing. Accordingly, the sample rack L pushed by the protrusion section 215 is output from the sample insertion unit 21 . As shown in FIG. 2 , the pre-processing unit 22 is provided on the left side of the sample insertion unit 21 and the wall on the right side of the pre-processing unit 22 is partially missed, so the sample rack L output from the rack output position 214 is introduced into the pre-processing unit 22 . In addition, two parallel belt conveyors, that is, a first transport line 216 and a second transport line 217 are provided in front of the rack placement section 211 . Portions on both right and left sides of the first transport line 216 and the second transport line 217 of the wall surrounding the rack placement section 211 of the sample insertion unit 21 are missed to introduce sample racks L into the first transport line 216 and the second transport line 217 and to discharge sample racks L to another unit from the first transport line 216 and the second transport line 217 . The bottom surface of the rack placement section 211 and the heights of the first transport line 216 and the second transport line 217 are uniformized and almost the uniform plane is formed. In addition, the sample insertion unit 21 is provided with a rack transfer section 218 for transferring a sample rack L introduced into the first transport line 216 or the second transport line 217 in the backward direction. Such a rack transfer section 218 has a horizontally long rod shape and is movable forward and backward in the range from the second transport line 217 to the central position in the front-back direction of the rack placement section 211 . Due to the backward movement of the rack transfer section 218 which is displaced in front of a sample rack L introduced into the first transport line 216 or the second transport line 217 , the rack transfer section 218 is brought into contact with the front surface of the sample rack L, and due to further backward movement of the rack transfer section 218 , the sample rack L is pushed and moved backward. Accordingly, the sample rack L is transferred backward up to a position past the engagement sections 211 a and then the sample rack L is transferred up to the rack output position 214 by the engagement sections 211 a . In this manner, the sample insertion unit 21 can directly output a sample rack L which is introduced by the first transport line 216 or the second transport line 217 to the sample recovery unit 23 on the right side, and can transfer a sample rack L on the first transport line 216 or the second transport line 217 up to the rack output position 214 and then output the sample rack to the pre-processing unit 22 on the left side. The sample insertion unit 21 having such a configuration includes a control section 21 a including a CPU, a memory and the like. The above-described mechanisms in the sample insertion unit 21 are controlled by this control section 21 a . In addition, the sample insertion unit 21 includes an Ethernet (registered trade name) interface and is connected to an information processing unit 54 and the system control apparatus 8 via a LAN so as to communicate therewith. The sample insertion unit 21 is provided with an operation panel 21 b . A user can give an instruction for starting or ending sample processing to the sample processing system 1 by operating the operation panel 21 b. The pre-processing system 22 is connected to the left side of the sample insertion unit 21 . A sample rack L output to the left side from the rack output position 214 is introduced into the pre-processing unit 22 . Such a pre-processing unit 22 includes a rack placement section 221 , which can accommodate a plurality of sample racks L and has a quadrangular shape in a planar view. In addition, the pre-processing unit 22 includes a barcode reading section 22 b on the inside of the rack placement section 221 . Such a barcode reading section 22 b can read sample barcodes of a plurality of sample containers T accommodated in a sample rack L at the same time and can also read a rack barcode of the sample rack L. Such a barcode reading section 22 b is provided with an optical sensor (not shown) for detecting a sample container T. When a sample rack L reaches a position at which the barcode reading section 22 b reads a barcode, whether there is a sample container T is detected by the optical sensor. In addition, the barcode reading section 22 b includes a horizontal rotating mechanism (not shown) which horizontally rotates a plurality of sample containers T immediately above the barcode reading position on the innermost side of the rack placement section 221 . A sample rack L output from the rack output position 214 of the rack insertion unit 21 is introduced leftward into the pre-processing unit 22 and reaches the barcode reading position. Then, while the horizontal rotating mechanism horizontally rotates a sample container T accommodated in the sample rack L, the barcode reading section 22 b reads out a sample ID from a barcode label BL 1 and reads out a rack ID from a barcode label BL 2 of the sample rack L. When the sample rack L reaches the barcode reading position, whether there is a sample container T is detected by the above-described optical sensor and the barcode reading section 22 b continuously reads a sample barcode of each of the sample containers T plural times. When data of the sample IDs, each of which is read plural times matches, the reading of the sample barcode is regarded as successful and the sample IDs and the read rack ID are transmitted to the system control apparatus 8 . Engagement sections 221 a protrude from both right and left walls of the rack placement section 221 . Such engagement sections 221 a engage with a sample rack L of which a rack barcode and sample barcodes have been read by the barcode reading section 22 b and moves forward. Accordingly, the sample rack L moves forward on the rack placement section 221 . The position on the foremost side of the rack placement section 221 serves as a rack output position 222 . A transport line 223 which is a belt conveyor is provided in front of this rack output position 222 and a partition section 224 having a wall shape protrudes between the transport line 223 and the rack output position 222 . The partition section 224 is provided with a protrusion section 225 which is movable left- and rightward. This protrusion section 225 waits at the position near the right end of the rack output position 222 until a sample rack L is transferred to the rack output position 222 . After the sample rack L reaches the rack output position 222 , the protrusion section moves leftward. The sample rack L is pushed by the protrusion section 225 and moves leftward. In addition, the walls on the both right and left sides of the rack output position 222 are missing. Accordingly, the sample rack L pushed by the protrusion section 225 is output from the pre-processing unit 22 . As shown in FIG. 1 , the sample transport apparatus 3 a is connected to the left side of the pre-processing unit 22 and the rack output position 222 linearly connects with an overtaking line to be described later of the sample transport apparatus 3 a . Accordingly, the sample rack L output from the rack output position 222 is introduced into the overtaking line of the sample transport apparatus 3 a. In addition, a barcode reader 222 a for reading a rack barcode is provided near the rack output position 222 . This barcode reader 222 a reads the rack ID of a sample rack L transported to the rack output position 222 and the read rack ID is transmitted to the system control apparatus 8 . As will be described later, the system control apparatus 8 receives this rack ID and decides a transport destination of the sample rack L in accordance with the rack ID. In addition, walls on both right and left sides of the transport line 223 are missed and the transport line 223 linearly connects with a return line to be described later of the sample transport apparatus 3 a and the above-described second transport line 217 of the sample insertion unit 21 . Accordingly, the transport line 223 receives a sample rack L from the return line of the sample transport apparatus 3 a and discharges this sample rack L to the second transport line 217 of the sample insertion unit 21 . The pre-processing unit 22 having such a configuration includes a control section 22 a including a CPU, a memory and the like. The above-described mechanisms in the pre-processing unit 22 are controlled by this control section 22 a . In addition, the pre-processing unit 22 includes an Ethernet (registered trade name) interface and is connected to the information processing unit 54 and the system control apparatus 8 via a LAN so as to communicate therewith. On the right side of the sample insertion unit 21 , sample recovery units 23 and 24 are laterally arranged side by side. The sample insertion unit 21 is connected to the leftmost sample recovery unit 23 . These sample recovery units 23 and 24 have the same configuration as that of the rack insertion unit 21 . That is, the sample recovery units 23 and 24 include concave-shaped rack placement sections 231 and 241 for placing sample racks L, engagement sections 231 a and 241 a for transferring sample racks L placed in the rack placement sections 231 and 241 backward, sensors 232 and 233 and 242 and 243 for detecting sample racks L, first transport lines 236 and 246 and second transport lines 237 and 247 which are provided in front of the rack placement sections 231 and 241 to transport sample racks L in the transverse direction, and rack transfer sections 238 and 248 for transferring sample racks L, which are introduced into the first transport lines 236 and 246 or the second transport lines 237 and 247 , to the rack placement sections 231 and 241 , respectively. The sample recovery units 23 and 24 are connected so that the first transport lines 236 and 246 linearly connect with each other and the second transport lines 237 and 247 linearly connect with each other. The sample recovery units 23 and 24 include control sections 23 a and 24 a including a CPU, a memory and the like, respectively. The above-described mechanisms in the sample recovery units 23 and 24 are controlled by these control sections 23 a and 24 a . In addition, the respective sample recovery units 23 and 24 include an Ethernet (registered trade name) interface and are connected to the information processing unit 54 and the system control apparatus 8 via a LAN so as to communicate therewith. The sample recovery unit 24 is used to recover a sample rack L in which the necessary measurement has been completed. In addition, the sample recovery unit 23 is used to recover a sample rack L in which the necessary measurement has not been completed due to the occurrence of trouble in the sample transport apparatus 3 a , 3 b or 3 c. <Configurations of Sample Transport Apparatuses 3 a , 3 b and 3 c> Next, the configurations of the sample transport apparatuses 3 a , 3 b and 3 c will be described. As shown in FIG. 1 , the sample rack transport system 100 includes the sample transport apparatuses 3 a , 3 b and 3 c . The sample transport apparatuses 3 a , 3 b and 3 c are disposed in front of three measuring units 51 , 52 and 53 of the blood cell analysis apparatus 5 , respectively. The neighboring sample transport apparatuses are connected to each other to deliver and receive a sample rack L. In addition, the rightmost sample transport apparatus 3 a is connected to the above-described sample insertion and recovery apparatus 2 to introduce a sample rack L discharged from the sample insertion and recovery apparatus 2 and to output a sample rack L to the sample insertion and recovery apparatus 2 . FIG. 5 is a plan view showing the configurations of the sample transport apparatuses 3 a , 3 b and 3 c . Here, the sample transport apparatus 3 a which is disposed in front of the measuring unit 51 will be described, but the sample transport apparatuses 3 b and 3 c which are disposed in front of the measuring units 52 and 53 , respectively, have the same configuration. As shown in FIG. 5 , the sample transport apparatus 3 a includes a transport mechanism 31 transporting a sample and a control section 32 controlling the transport mechanism 31 . The transport mechanism 31 includes a pre-analysis rack holding section 33 capable of temporarily holding a sample rack L which holds a sample container T containing a sample before analysis, a post-analysis rack holding section 34 capable of temporarily holding a sample rack L which holds a sample container T in which a sample has been suctioned by the corresponding measuring unit 51 , a rack transport section 35 which horizontally and linearly moves a sample rack L in the direction of the arrow X in the drawing to supply the sample rack to the measuring unit 51 and transports the sample rack L received from the pre-analysis rack holding section 33 to the post-analysis rack holding section 34 , a rack overtaking transport section 321 which introduces a sample rack L from the apparatus (any one of the sample insertion and recovery apparatus 2 and the sample transport apparatus 3 a and 3 b ) further to the upstream side of the transport and discharges the sample rack L to the apparatus (any one of the sample transport apparatuses 3 b and 3 c and the sample transport apparatus 4 ) further to the downstream side of the transport without supply of a sample contained in this sample rack L to the measuring unit 51 , and a rack return transport section 331 which introduces a sample rack L from the apparatus (any one of the sample transport apparatuses 3 b and 3 c and the sample transport apparatus 4 ) further to the downstream side of the transport and discharges the sample rack L to the apparatus (any one of the sample insertion and recovery apparatus 2 and the sample transport apparatus 3 a and 3 b ) further to the upstream side of the transport without supply of a sample contained in this sample rack L to the measuring unit 51 . Each of the rack overtaking transport section 321 and the rack return transport section 331 have a transport belt for transporting a rack and a stepping motor driving the transport belt. The rack overtaking transport section 321 transports a sample rack L by driving the transport belt with the stepping motor in the transport downstream direction. In addition, the rack return transport section 331 transports a sample rack L by driving the transport belt with the stepping motor in the transport upstream direction. When a sample rack L in the post-analysis rack holding section 34 is detected by optical sensors 34 a and 34 b including a light-emitting section and a light-receiving section, rack feeding mechanisms 34 c move while engaging with the rear ends of the sample rack L and thus the sample rack L is positioned at any one of a rack overtaking position 321 a and a rack return position 331 a . Sensors 321 b and 331 b are provided near the rack overtaking position 321 a and the rack return position 331 a , respectively, and can detect the fact that a sample rack L has been positioned at the above position. The control section 32 includes a CPU, a ROM, a RAM and the like (not shown). A control program of the transport mechanism 31 which is stored in the ROM can be executed by the CPU. In addition, such a control section 32 includes an Ethernet (registered trade name) interface and is connected to the information processing unit 54 and the system control apparatus 8 via a LAN so as to communicate therewith. The sample transport apparatus 3 a transports a sample rack L, which is transported from the sample insertion and recovery apparatus 2 , to a pre-analysis rack output position 323 by the rack overtaking transport section 321 , transfers the sample rack to the pre-analysis rack holding section 33 by a rack output section 322 , outputs this sample rack L to the rack transport section 35 from the pre-analysis rack holding section 33 by rack feeding sections 33 b , and transports the sample rack by the rack transport section 35 to supply a sample to the corresponding measuring unit 51 ( 52 , 53 ) of the blood cell analysis apparatus 5 . A sensor 324 capable of detecting the fact that a sample rack L is positioned at the position 323 is provided near the pre-analysis rack output position 323 . In addition, the sample rack L containing the sample in which the suction has been completed is transferred to a post-analysis rack output position 391 by the rack transport section 35 and is output to the post-analysis rack holding section 34 by a rack output section 39 . The sample rack L held in the post-analysis rack holding section 34 is transferred to the rack overtaking transport section 321 and is discharged to the subsequent apparatus by the rack overtaking transport section 321 when the sample which is contained in this sample rack L is required to be measured by the measuring unit 52 or 53 on the transport direction downstream side or to be provided to the preparation of a smear by the smear preparation apparatus 6 . When there is no need to perform the measurement by the measuring unit 52 or 53 on the transport direction downstream side and the preparation of a smear by the smear preparation apparatus 6 on all of the samples which are held in the sample rack L held in the post-analysis rack holding section 34 , the sample rack L is transferred to the rack return transport section 331 and is discharged to the preceding apparatus (on the upstream side in the transport direction) by the rack return transport section 331 . In addition, when the sample rack L containing a sample to be processed by the measuring unit 52 or 53 further to the downstream side of the transport or by the smear preparation apparatus 6 is received from the preceding apparatus, this sample rack L is transported in the direction of the arrow X 1 by the rack overtaking transport section 321 and is directly discharged to the subsequent apparatus 3 . When the sample rack L which is recovered by the sample insertion and recovery apparatus 2 is received from the subsequent apparatus, this sample rack L is transported in the direction of the arrow X 2 by the rack return transport section 331 and is directly discharged to the preceding sample insertion and recovery apparatus 2 or sample transport apparatus 3 . In the transport mechanism 31 , the rack feeding sections 33 b , the rack transport section 35 and the rack output section 39 are controlled by the information processing unit 54 of the blood cell analysis apparatus 5 . The other parts in the transport mechanism 31 are controlled by the control section 32 . <Configuration of Sample Transport Apparatus 4 > As shown in FIG. 1 , the sample transport apparatus 4 is disposed in front of the smear preparation apparatus 6 . This sample transport apparatus 4 is connected to the sample transport apparatus 3 c at the right end thereof. FIG. 6 is a plan view showing the configuration of the sample transport apparatus 4 . The sample transport apparatus 4 includes a transport mechanism 41 transporting a sample and a control section 42 controlling the transport mechanism 41 . The transport mechanism 41 includes a pre-processing rack holding section 43 capable of temporarily holding a sample rack L which holds a sample container T containing a sample before preparation of a smear, a post-processing rack holding section 44 capable of temporarily holding a sample rack L which holds a sample container T in which a sample has been suctioned by the smear preparation apparatus 6 , a rack transport section 45 which horizontally and linearly moves a sample rack L in the X 1 direction to supply the sample to the smear preparation apparatus 6 and transports the sample rack L received from the pre-processing rack holding section 43 to the post-processing rack holding section 44 , a rack overtaking transport section 421 which introduces a sample rack L from the sample transport apparatus 3 c further to the upstream side of the transport and transports the sample rack L in the X 1 direction, and a rack return transport section 431 which discharges a sample rack L to the sample transport apparatus 3 c further to the upstream side of the transport in order to recover the sample rack L in which the preparation of smears of samples has been completed by the sample insertion and recovery apparatus 2 . The sample transport apparatus 4 is different from the sample transport apparatuses 3 a , 3 b and 3 c in sizes, shapes and positions of the constituent components. However, since the functions are the same, the description of the configuration thereof will be omitted. The sample transport apparatus 4 introduces a sample rack L, which is discharged from the sample transport apparatus 3 c on the upstream side, by the rack overtaking transport section 421 , transfers the sample rack to the pre-processing rack holding section 43 by a rack output section (not shown), outputs this sample rack L to the rack transport section 45 from the pre-processing rack holding section 43 , and transport the sample rack by the rack transport section 45 to supply a sample to the smear preparation apparatus 6 . In addition, the sample rack L containing the sample in which the suction has been completed is transported by the rack transport section 45 and is output to the post-processing rack holding section 44 by the rack output section (not shown). The sample rack L held in the post-processing rack holding section 44 is transferred to the rack return transport section 431 and is discharged to the preceding sample transport apparatus 3 c (on the upstream side in the transport direction) by the rack return transport section 431 . <Configuration of Blood Cell Analysis Apparatus 5 > The blood cell analysis apparatus 5 is an optical flow cytometry type multiple blood cell analysis apparatus. This apparatus obtains side-scattered light intensity, fluorescence intensity and the like with respect to blood cells included in a blood sample, classifies blood cells included in the sample on the basis of the above obtained results, counts the number of blood cells for each kind, and creates and displays a scattergram in which the classified blood cells are colored in different colors for each kind. Such a blood cell analysis apparatus 5 includes the measuring units 51 , 52 and 53 which measure a blood sample and the information processing unit 54 which processes measurement data output from the measuring units 51 , 52 and 53 and displays a blood sample analysis result. As shown in FIG. 1 , the blood cell analysis apparatus 5 includes the three measuring units 51 , 52 and 53 and the single information processing unit 54 . The information processing unit 54 is connected to the three measuring units 51 , 52 and 53 so as to communicate therewith and can control the operations of the three measuring units 51 , 52 and 53 . In addition, the information processing unit 54 is connected to the three sample transport apparatuses 3 a , 3 b and 3 c which are disposed in front of the three measuring units 51 , 52 and 53 , respectively, so as to communicate therewith. FIG. 7 is a block diagram showing the configuration of the measuring unit 51 . As shown in FIG. 7 , the measuring unit 51 has a sample suction section 511 suctioning blood which is a sample from the sample container (blood collection tube) T, a specimen preparation section 512 preparing a measurement specimen which is used in measurement from the blood suctioned by the sample suction section 511 and a detecting section 513 detecting blood cells from the measurement specimen prepared by the specimen preparation section 512 . In addition, the measuring unit 51 further has an intake port (not shown) for taking a sample container T which is accommodated in a sample rack L transported by the rack transport section 35 of the sample transport apparatus 3 a into the measuring unit 51 and a sample container transport section 515 which takes a sample container T from a sample rack L into the measuring unit 51 and transports the sample container T up to a position at which the sample suction section 511 performs suction. A suction tube (not shown) is provided at the tip end of the sample suction section 511 . In addition, the sample suction section 511 is vertically movable and is configured to move downward so that the suction tube penetrates a cap section CP of a sample container T transported up to the suction position and suctions blood in the sample container. The specimen preparation section 512 includes a plurality of reaction chambers (not shown). In addition, the specimen preparation section 512 is connected to reagent containers (not shown) and can supply reagents such as a dyeing reagent, a hemolytic agent and a diluent solution to the reaction chambers. The specimen preparation section 512 is also connected to the suction tube of the sample suction section 511 and can supply a blood sample suctioned by the suction tube to the reaction chambers. Such a specimen preparation section 512 mixes and stirs a sample and a reagent in the reaction chamber and prepares a specimen (measurement specimen) for the measurement by the detecting section 513 . The detecting section 513 can perform RBC (red blood cells) detection and PLT (platelets) detection by a sheath flow DC detection method. In the RBC and PLT detection by this sheath flow DC detection method, a measurement specimen in which a sample and a diluent solution are mixed is measured and measurement data obtained by the measurement is analyzed and processed by the information processing unit 54 , and thus the RBC and PLT measurement is performed. In addition, the detecting section 513 can perform HGB (hemoglobin) detection by a SLS-hemoglobin method and is configured to perform WBC (white blood cells) detection by a flow cytometry method using a semiconductor laser. In this detecting section 513 , a measurement specimen in which a sample, a hemolytic agent and a diluent solution are mixed is measured and measurement data obtained by the measurement is analyzed and processed by the information processing unit 54 , and thus the WBC measurement is performed. The RBC, PLT, HGB and WBC are measured when a measurement item complete blood count (CBC) is designated. The sample container transport section 515 includes a hand section 515 a capable of gripping a sample container T. The hand section 515 a includes a pair of gripping members which are disposed to be opposed to each other, and can move the gripping members closer to each other and separate the gripping members from each other. When such gripping members are moved closer to each other while gripping a sample container T, the sample container T can be gripped. In addition, the sample container transport section 515 can move the hand section 515 a in the vertical direction and in the forward and backward directions (Y direction) and can oscillate the hand section 515 a . Accordingly, when a sample container T which is accommodated in a sample rack L and is positioned at a sample supply position is gripped by the hand section 515 a , and in this state, when the hand section 515 a is moved upward to remove the sample container T from the sample rack L and is oscillated, the sample in the sample container T can be stirred. In addition, the sample container transport section 515 includes a sample container setting section 515 b having a hole into which a sample container T can be inserted. The sample container T gripped by the above-described hand section 515 a is moved after completion of stirring and the gripped sample container T is inserted into the hole of the sample container setting section 515 b . Then, by separating the gripping members from each other, the sample container T is set in the sample container setting section 515 b . Such a sample container setting section 515 b can horizontally move in the Y direction by a power of a stepping motor (not shown). In the measuring unit 51 , a barcode reading section 516 is provided. The sample container setting section 515 b can move to a barcode reading position 516 a near the barcode reading section 516 and to a position 511 a at which the sample suction section 511 performs suction. When the sample container setting section 515 b moves to the barcode reading position 516 a , a set sample container T is horizontally rotated by the rotating mechanism (not shown) and a sample barcode is read by the barcode reading section 516 . Accordingly, even when the barcode label BL 1 of the sample container T is positioned on the opposite side to the barcode reading section 516 , the barcode label BL 1 can turn toward the barcode reading section 516 by rotating the sample container T and the sample barcode can be read by the barcode reading section 516 . When the sample container setting section 515 b moves to the suction position, the sample is suctioned from a set sample container T by the sample suction section 511 . The measuring units 52 and 53 have the same configuration as that of the measuring unit 51 and include a sample suction section, a specimen preparation section, a detecting section and a sample container transport section. However, the detecting section of the measuring unit 52 is different from the detecting section 513 of the measuring unit 51 and can perform a white blood cell-5-classification (measurement item DIFF) as well as CBC. In greater detail, the detecting section of the measuring unit 52 is configured to perform detection of WBC (white blood cells), NEUT (neutrophils), LYMPH (lymphocytes), EO (eosinophiles), BASO (basophils) and MONO (monocytes) by a flow cytometry method using a semiconductor laser. In such a detecting section of the measurement unit 52 , a measurement specimen in which a dyeing reagent, a hemolytic agent and a diluent solution are mixed is measured and measurement data obtained by the measurement is analyzed and processed by the information processing unit 54 , and thus the measurement of NEUT, LYMPH, EO, BASO, MONO and WBC is performed. The detecting section of the measuring unit 53 is different from the detecting sections of the measuring units 51 and 52 and can measure reticulocytes (RET) in addition to CBC and DIFF. In order to perform the measurement of RET, a measurement specimen is prepared by mixing a reagent for RET measurement and a sample and the measurement specimen is supplied to an optical detecting section for WBC/DIFF (white blood cell-5-classification) detection of the detecting section. Next, the configuration of the information processing unit 54 will be described. The information processing unit 54 is composed of a computer. FIG. 8 is a block diagram showing the configuration of the information processing unit 54 . The information processing unit 54 is realized by a computer 54 a . As shown in FIG. 8 , the computer 54 a includes a main body 541 , an image display section 542 and an input section 543 . The main body 541 includes a CPU 541 a , a ROM 541 b , a RAM 541 c , a hard disk 541 d , a reading device 541 e , an I/O interface 541 f , a communication interface 541 g and an image output interface 541 h . The CPU 541 a , the ROM 541 b , the RAM 541 c , the hard disk 541 d , the reading device 541 e , the I/O interface 541 f , the communication interface 541 g and the image output interface 541 h are connected to each other by a bus 541 j. The reading device 541 e reads out a computer program 544 a for prompting the computer to function as the information processing unit 54 from a portable recording medium 544 and can install the computer program 544 a on the hard disk 541 d. <Configuration of Smear Preparation Apparatus 6 > The smear preparation apparatus 6 suctions a blood sample from a sample container T in a sample rack L, drops the sample onto a glass slide, thinly extends the blood sample on the glass slide and dries the sample. Then, the smear preparation apparatus supplies a dyeing solution to the glass slide to dye the blood on the glass slide, thereby preparing a smear. <Configuration of System Control Apparatus 8 > The system control apparatus 8 is composed of a computer and controls the entire sample processing system 1 . This system control apparatus 8 receives the number of a sample rack L from the sample insertion and recovery apparatus 2 and decides the transport destination of the sample rack L. In addition, the system control apparatus 8 monitors operation states of the respective apparatuses in the sample processing system 1 , and when trouble occurs in the respective apparatuses, the system control apparatus can immediately detect the trouble. FIG. 9 is a block diagram showing the configuration of the system control apparatus 8 according to this embodiment. The system control apparatus 8 is realized by a computer 8 a . As shown in FIG. 9 , the computer 8 a includes a main body 81 , an image display section 82 and an input section 83 . The main body 81 includes a CPU 81 a , a ROM 81 b , a RAM 81 c , a hard disk 81 d , a reading device 81 e , an I/O interface 81 f , a communication interface 81 g and an image output interface 81 h . The CPU 81 a , the ROM 81 b , the RAM 81 c , the hard disk 81 d , the reading device 81 e , the I/O interface 81 f , the communication interface 81 g and the image output interface 81 h are connected to each other by a bus 81 j. The reading device 81 e reads out a system control program 84 a for prompting the computer to function as the system control apparatus 8 from a portable recording medium 84 and can install the system control program 84 a on the hard disk 81 d. <Configuration of Examination Information Management Apparatus 9 > The examination information management apparatus 9 is an apparatus which manages information relating to examinations in facilities, that is, a so-called laboratory information system (LLS), and is connected not only to the blood cell analysis apparatus 5 , but also to another clinical sample examination apparatus. Such an examination information management apparatus 9 receives a measurement order, which is input from an operator or is transmitted from another apparatus such as an electronic health record system, and stores and manages the measurement order. Further, the examination information management apparatus 9 receives an order request from the system control apparatus 8 , transmits the requested measurement order to the system control apparatus 8 , receives an analysis result from the blood cell analysis apparatus 5 , and stores and manages this analysis result. The examination information management apparatus 9 is composed of a computer and includes a CPU, a ROM, a RAM, a hard disk, a communication interface and the like. The communication interface is connected to the above-described LAN and can communicate with the system control apparatus 8 and the information processing unit 54 of the blood cell analysis apparatus 5 . In addition, measurement orders are stored in the hard disk. In the measurement order, a sample ID and information regarding measurement items of an execution target are included. When receiving request data of a measurement order including a sample ID from another apparatus, the examination information management apparatus 9 reads out measurement data corresponding to this sample ID from the hard disk and transmits the measurement data to the apparatus which is the request source. Since the configuration of the examination information management apparatus 9 is the same as the configurations of the above-described other computers, the description thereof will be omitted. [Operation of Sample Processing System] Hereinafter, the operation of the sample processing system 1 according to this embodiment will be described. <Sample Discharge Operation of Sample Insertion and Recovery Apparatus 2 > FIG. 10 is a flowchart showing the flow of a sample discharge operation of the sample insertion and recovery apparatus 2 . When sample processing is started by the sample processing system 1 , first, an operator operates the operation panel 21 b of the sample insertion unit 21 to give a sample processing start instruction to the sample processing system 1 . In this state, when a sample rack L is inserted into the sample insertion unit 21 , the sample rack L placed in the rack placement section 211 is detected by the sensors 212 and 213 (Step S 101 ). A control program which is executed by the control section 21 a of the sample insertion unit 21 is an event-driven program, and the control section 21 a of the sample insertion unit 21 executes the process of Step S 102 when the sensors 212 and 213 detect the sample rack L. In Step S 102 , the control section 21 a drives the engagement sections 211 a to move the sample rack L backward until the sample rack reaches the rack output position 214 . Further, the control section drives the protrusion section 215 to output the sample rack L to the pre-processing unit 22 (Step S 102 ). The sample rack L output from the rack output position 214 of the rack insertion unit 21 is introduced into the pre-processing unit 22 in the leftward direction and reaches the barcode reading position. When the sample rack L reaches the barcode reading position, the control section 22 a of the pre-processing unit 22 controls the barcode reading section 22 b and reads a rack ID of the sample rack and sample IDs of sample containers T which are held in the sample rack L (Step S 103 ). When the sample rack L reaches the barcode reading position, whether there is a sample container T is detected by the optical sensor of the barcode reading section 22 b , and by the barcode reading section 22 b , a sample barcode of each of the sample containers T is continuously read plural times. When data of the sample IDs each of which is read plural times matches, the reading of the sample barcode is regarded as successful. In this manner, the sample IDs are read from the sample barcodes of all the sample containers T held in the sample rack L. The holding positions in the sample rack L are associated with the sample IDs read from the sample containers which are respectively held in the holding positions, and are stored in the control section 22 a. Next, the control section 22 a controls the engagement sections 221 a to transfer the sample rack L to the rack output position 222 on the rack placement section 221 (Step S 104 ) and transmits the stored rack ID, holding positions and sample IDs to the system control apparatus 8 (Step S 105 ). As will be described later, the system control apparatus 8 receiving the rack ID, holding positions and sample IDs inquires the examination information management apparatus 9 of measurement orders and stores the measurement orders in association with the rack ID, holding positions and sample IDs. When the sample rack L reaches the rack output position 222 , the control section 22 a controls the barcode reader 222 a to read the rack ID from the rack barcode of the sample rack L (Step S 106 ) and transmits discharge instruction request data including the read rack ID to the system control apparatus 8 (Step S 107 ). When receiving this discharge instruction request data, the system control apparatus 8 searches a measurement order corresponding to the same rack ID from the hard disk, decides a transport destination of the sample rack L on the basis of the search and transmits transport instruction data for transporting the sample rack L to the decided transport destination to the pre-processing unit 22 . The control section 22 a waits to receive the transport instruction data from the system control apparatus 8 (NO in Step S 108 ). When receiving the transport instruction data (YES in Step S 108 ), the control section controls the protrusion section 225 to output the sample rack L from the rack output position 222 in the leftward direction (Step S 109 ) and ends the process. Every time a new sample rack L is inserted into the sample insertion unit 21 , the processes of the above-described Steps S 101 to S 109 are executed. <Measurement Order Obtaining Operation of System Control Apparatus 8 > FIG. 11 is a flowchart showing the flow of a measurement order obtaining operation of the system control apparatus 8 . The system control apparatus 8 receives the rack ID, holding positions and sample IDs transmitted from the pre-processing unit 22 via the communication interface 81 g (Step S 111 ). The system control program 84 a is an event-driven program, and the CPU 81 a executes the process of Step S 112 when receiving the rack ID, holding positions and sample IDs. In Step S 112 , for all of the received sample IDs, the CPU 81 a inquires the examination information management apparatus 9 of measurement orders by transmitting measurement order request data including the sample IDs to the examination information management apparatus 9 (Step S 112 ). Next, the CPU 81 a waits to receive the measurement orders (NO in Step S 113 ). When receiving the measurement orders (YES in Step S 113 ), the CPU stores the measurement orders in the hard disk 81 d in association with the rack ID, holding positions and sample IDs (Step S 114 ) and ends the process. <First Transport Instruction Operation of System Control Apparatus 8 > FIG. 12 is a flowchart showing the flow of a first transport instruction operation of the system control apparatus 8 . When receiving the discharge instruction request data (rack ID) via the communication interface 81 g (Step S 121 ), the CPU 81 a searches a measurement order associated with the received rack ID from the hard disk 81 d (Step S 122 ). Next, the CPU 81 a determines whether trouble information has been received (Step S 123 ). The sample transport apparatuses 3 a , 3 b , 3 c and 4 transmit trouble information including information (for example, trouble code) showing the kind of occurring trouble to the system control apparatus 8 when trouble such as breakdown occurs. When determining that the trouble information has not been received (NO in Step S 123 ), the CPU 81 a specifies the measuring unit 51 , 52 or 53 which can most rapidly start sample processing and decides the specified unit as the transport destination of the sample rack L (Step S 124 ). The CPU 81 a manages the transport status of the sample rack L in real time and can determine which one of the measuring units 51 , 52 and 53 the sample is supplied to most rapidly start sample processing. The CPU 81 a manages the transport status of the sample rack L by inquiring the respective sample transport apparatuses 3 a , 3 b and 3 c of whether the sample rack L is held in the pre-analysis rack holding section 33 . For example, when the sample rack L is held in the pre-analysis rack holding section 33 of the sample transport apparatus 3 a , the CPU 81 a determines that the measuring unit 51 cannot receive the sample rack L. That is, in Step S 124 , the CPU 81 a decides as the transport destination the measuring unit which can measure measurement items included in the measurement order of the sample held in the sample rack L and can receive the sample rack L. When determining that the trouble information has been received (YES in Step S 123 ), the CPU 81 a determines whether the trouble occurred in the sample transport apparatus 3 a on the basis of the trouble information (Step S 125 ). When determining that the trouble occurred in the sample transport apparatus 3 a (YES in Step S 125 ), the CPU 81 a stops the operation of transporting the sample rack L in the sample rack transport system 100 (Step S 126 ) and waits for elimination of the trouble in the sample transport apparatus 3 a (Step S 127 ). When determining that the trouble in the sample transport apparatus 3 a has been eliminated (YES in Step S 127 ), the CPU 81 a executes the process of Step S 121 . When determining that the trouble did not occur in the sample transport apparatus 3 a , that is, when determining that the trouble occurred in the sample transport apparatus 3 b or 3 c (NO in Step S 125 ), the CPU 81 a determines whether there is the transport unit which can transport the sample rack L (Step S 128 ). Here, the CPU 81 a determines whether the sample rack L can be transported to the measuring unit which can measure measurement items of the measurement order of the sample held in the sample rack L. Hereinafter, a case in which the trouble occurs in the sample transport apparatus 3 b will be described as a concrete example. When trouble occurs in the sample transport apparatus 3 b , the sample rack L cannot be transported to the measuring units 52 and 53 . Accordingly, when DIFF or RET is included in the measurement items of the measurement order of the sample held in the sample rack L, the CPU 81 a determines that the sample rack L cannot be transported. On the other hand, when DIFF or RET is not included in the measurement items of the measurement order of the sample held in the sample rack L, the CPU 81 a determines that the sample rack L can be transported to the measuring unit 51 . When determining that there is the transport unit which can transport the sample rack L (YES in Step S 128 ), the CPU 81 a decides as the transport destination the measuring unit which can perform measurement on the sample rack L (Step S 129 ). According to the above-described concrete example, the CPU 81 a decides the measuring unit 51 as the transport destination of the sample rack L. In addition, when determining that there is no transport unit which can transport the sample rack L (NO in Step S 128 ), the CPU 81 a decides the sample recovery unit 23 as the transport destination of the sample rack L (Step S 130 ). Next, the CPU 81 a transmits transport instruction data showing an instruction for transporting the sample rack L to the transport destination to the sample insertion unit 2 and the sample transport apparatuses 3 a , 3 b and 3 c (Step S 130 ) and ends the process. This transport instruction data includes the rack ID of the sample rack L and the holding positions, sample IDs and measurement orders of all the samples which are held in the sample rack L. In the above-described concrete example, the CPU 81 a transmits the transport instruction data to the sample transport apparatus 3 a and the sample insertion and recovery apparatus 2 . <First Transport Operation of Sample Transport Apparatuses 3 a , 3 b and 3 c> FIG. 13 is a flowchart showing the flow of a first transport operation of the sample transport apparatuses 3 a , 3 b and 3 c . When the transport instruction data is received, the control section 22 a of the pre-processing unit 22 moves the protrusion section 225 leftward to discharge the sample rack L at the rack output position 222 to the rack overtaking transport section 321 of the sample transport apparatus 3 a . Meanwhile, when the transport instruction data is received (Step S 131 ), the control section 32 of the sample transport apparatus 3 determines whether the transport destination of the sample rack L is the measuring unit corresponding to the sample transport apparatus on the basis of the received transport instruction data (Step S 132 ). That is, the control section 32 of the sample transport apparatus 3 a determines whether the transport destination of the sample rack L is the measuring unit 51 , the control section 32 of the sample transport apparatus 3 b determines whether the transport destination of the sample rack L is the measuring unit 52 , and the control section 32 of the sample transport apparatus 3 c determines whether the transport destination of the sample rack L is the measuring unit 53 . When determining that the transport destination is the corresponding measuring unit (YES in Step S 132 ), the control section 32 controls the driving of the transport mechanism 31 , introduces the sample rack L by the rack overtaking transport section 321 and moves the sample rack L positioned at the pre-analysis rack output position 323 to the pre-analysis rack holding section 33 by moving the rack output section 322 forward (Step S 133 ). In addition, the control section 32 transmits the rack ID of the sample rack L and the holding positions, sample IDs and measurement instruction data including measurement orders of all the samples which are held in the sample rack L to the information processing unit 54 (step S 134 ) and ends the process. On the other hand, when determining that the transport destination is not the corresponding measuring unit (NO in Step S 132 ) the control section 32 determines whether the transport destination of the sample rack L is the sample insertion and recovery apparatus 2 , that is, whether the transport destination is the sample recovery unit 23 or 24 or not (Step S 135 ). When determining that the transport destination is the sample insertion and recovery apparatus 2 (the sample recovery unit 23 or 24 ) (YES in Step S 135 ), the control section 32 controls the driving of the transport mechanism 31 , transfers the sample rack L to the rack return transport section 331 by the rack feeding mechanisms 34 c , discharges the sample rack L to the preceding apparatus by the rack return transport section 331 (Step S 136 ) and ends the process. When determining that the transport destination is not the sample insertion and recovery apparatus 2 (the sample recovery unit 23 or 24 ) (NO in Step S 135 ), the control section 32 controls the driving of the transport mechanism 31 , introduces the sample rack L by the rack overtaking transport section 321 , directly discharges the sample rack L to the subsequent apparatus (Step S 137 ) and ends the process. Here, a transport operation by the sample transport apparatus 3 a when the sample rack L for which the rack recovery unit 23 is the transport destination is discharged by the pre-processing unit 22 will be described. When the sample rack L is not detected by the sensors 34 a and 34 b of the post-analysis rack holding section 34 , the sample transport apparatus 3 a transfers the sample rack L, which is discharged from the pre-processing unit 22 , to the rack overtaking position 321 a by the rack overtaking transport section 321 , transfers the sample rack to the rack return position 331 a by the rack feeding mechanisms 34 c and discharges the sample rack to the sample insertion and recovery apparatus 2 by the rack return transport section 331 . On the other hand, when the sample rack L is detected by the sensors 34 a and 34 b of the post-analysis rack holding section 34 , the operations of the sample transport apparatus 3 a are different in accordance with which one of the detection of the sample rack L by the sensors 34 a and 34 b and the reading of the rack ID by the barcode reader 222 a of the pre-processing unit 22 is more rapidly performed. First, when the detection of the sample rack L by the sensors 34 a and 34 b is more rapidly performed, the pre-processing unit 22 waits for the transport of the sample rack L. Meanwhile, the sample transport apparatus 3 a transfers the sample rack L in the post-analysis rack holding section 34 to the rack overtaking position 321 a or the rack return position 331 a by the rack feeding mechanisms 34 c and transports the sample rack L by the rack overtaking transport section 321 or the rack return transport section 331 . Then, the pre-processing unit 22 discharges the sample rack L, and the sample transport apparatus 3 transfers the discharged sample rack L to the rack overtaking position 321 a by the rack overtaking transport section 321 , transfers the sample rack to the rack return position 331 a by the rack feeding mechanisms 34 c and transports the sample rack to the sample insertion and recovery apparatus 2 by the rack return transport section 331 . Next, when the reading of the rack ID by the barcode reader 222 a of the pre-processing unit 22 is more rapidly performed, the sample transport apparatus 3 a causes the sample rack L transferred to the post-analysis rack holding section 34 to wait in the post-analysis rack holding section 34 , transfers the sample rack L discharged from the sample insertion and recovery apparatus 2 to the rack overtaking position 321 a by the rack overtaking transport section 321 , transfers the sample rack to the rack return position 331 a by the rack feeding mechanisms 34 c , and transports the sample rack to the sample insertion and recovery apparatus 2 by the rack return transport section 331 . Then, the sample transport apparatus 3 a transfers the sample rack L in the post-analysis rack holding section 34 to the rack return position 331 a by the rack feeding mechanisms 34 c , transfers the sample rack to the rack overtaking position 321 a or the rack return position 331 a by the rack feeding mechanisms 34 c and transports the sample rack L by the rack overtaking transport section 321 or the rack return transport section 331 . FIG. 14 is a flowchart showing the flow of a transport destination chance process of the system control apparatus 8 . This process is a process for changing the transport destination of the sample rack L which is inserted into the sample transport apparatus when trouble occurs. In the hard disk 81 d of the system control apparatus 8 , the transport destination of the sample rack L which is inserted into the sample transport apparatus is stored. When receiving trouble information from the sample transport apparatus (Step S 141 ), the CPU 81 a searches the transport destination of the sample rack L from the hard disk 81 d (S 142 ). Next, on the basis of the search result in Step S 142 , the CPU 81 a determines whether the inserted sample rack L can be transported to the transport destination when trouble occurs (Step S 143 ). For example, when trouble occurs in the sample transport apparatus 3 b , the sample rack L can be transported to the measuring unit 51 , but cannot be transported to the measuring units 52 and 53 . Accordingly, when trouble occurs in the sample transport apparatus 3 b , the CPU 81 a determines that the sample rack L can be transported to the transport destination when the transport destination of the sample rack L is the measuring unit 51 . When the transport destination of the sample rack L is the measuring unit 52 or 53 , the CPU 81 a determines that the sample rack L cannot be transported to the transport destination. When determining that the sample rack L cannot be transported to the transport destination (YES in Step S 143 ), the CPU 81 a changes the transport destination of the sample rack L to the sample recovery unit 23 (Step S 144 ), transmits transport instruction data to the sample insertion and recovery apparatus 2 and the sample transport apparatuses 3 a , 3 b and 3 c (Step S 145 ) and ends the process. In addition, the CPU 81 a ends the process also when determining that the sample rack L can be transported to the transport destination (NO in Step S 143 ). <Rack Transport Control Operation of Blood Cell Analysis Apparatus 5 > FIG. 15 is a flowchart showing the flow of a rack transport control operation of the blood cell analysis apparatus 5 . The CPU 541 a of the information processing unit 54 of the blood cell analysis apparatus 5 detects the sample rack L in the pre-analysis rack holding section 33 by the rack sensors provided in the sample transport apparatus 3 a , 3 b and 3 c (Step S 151 ). When receiving measurement instruction data from the sample transport apparatus 3 a , 3 b and 3 c (Step S 152 ), the CPU executes the process of Step S 153 . In Step S 153 , the CPU 541 a moves the rack feeding sections 33 b backward to transfer the sample rack L to the rack transport section 35 . Next, the CPU 541 a controls the driving of the rack transport section 35 and transports the sample rack L so as to position the sample container T at the sample supply position (Step S 154 ). In a sample analysis operation to be described later, the sample container T which is positioned at the sample supply position is removed from the sample rack L and taken into the measuring unit. The sample is suctioned from the sample container T and is analyzed. When the suction of the sample in the measuring unit is completed, the sample container T is returned to the sample rack L. In addition, the CPU 541 a determines whether all the sample containers T in the sample rack L have been taken (Step S 155 ). When determining that all the sample containers T in the sample rack L have not been taken (NO in Step S 155 ), that is, when there is a sample container T which has not been taken, the CPU 541 a controls the driving of the rack transport section 35 to transport the sample rack L so that the holding position at which the next sample container T is detected is positioned at the sample supply position (Step S 156 ) and returns the process to Step S 155 . In Step S 155 , when determining that all the sample containers T which are held in the sample rack L have been taken (YES in Step S 155 ), the CPU 541 a controls the driving of the rack transport section 35 to transport the sample rack L up to the post-analysis rack output position 391 and further controls the driving of the rack output section 39 to transfer the sample rack L to the post-analysis rack holding section 34 (Step S 157 ), transmits measurement completion notification data including the rack ID of the sample rack L to the corresponding sample transport apparatus (Step S 158 ) and ends the process. <Sample Analysis Operation of Blood Cell Analysis Apparatus 5 > FIG. 16 is a flowchart showing the flow of a sample analysis operation of the blood cell analysis apparatus 5 . The above-described rack transport control operation of the blood cell analysis apparatus 5 and the present sample analysis operation are executed in parallel by a multitasking process. The CPU 541 a executes the process of Step S 172 when the sample container T which is held in the sample rack L reaches the sample supply position (Step S 171 ). In Step S 172 , the CPU 541 a removes the sample container T positioned at the sample supply position from the sample rack L and takes the sample container into the measuring unit by controlling the sample container transport section 515 of the measuring unit (Step S 172 ). Further, the CPU 541 a oscillates the sample container T by controlling the hand section 515 a to stir the sample therein, and then controls the sample container transport section 515 to transport the sample container T to the barcode reading position 516 and reads the sample barcode of the sample container T by the barcode reading section 516 , thereby obtaining the sample ID (Step S 173 ). Then, the CPU 541 a measures the sample by using a measurement order included in the measurement instruction data (step S 174 ). The CPU 541 a suctions the sample in an amount necessary for measurement from the sample container T, prepares a measurement specimen, starts the measurement of the sample, and then controls the sample container transport section 515 of the measuring unit to return the sample container T to the sample rack L from the measuring unit (Step S 175 ). Then, in the above-described rack transport control operation, the rack transport section 35 is controlled and the sample rack L is thus transported in the X 1 direction. The CPU 541 a processes measurement data which is obtained by measuring the sample and obtains a sample analysis result (Step S 176 ). Next, the CPU 541 a transmits the obtained analysis result to the system control apparatus 8 and the examination information management apparatus 9 (Step S 177 ) and ends the process. <Second Transport Instruction Operation of System Control Apparatus 8 > FIG. 17 is a flowchart showing the flow of a second transport instruction operation of the system control apparatus 8 . As will be described later, the sample rack L, in which the samples were measured and which was transferred to the post-analysis rack holding section 34 from the post-analysis rack output position 391 , is detected by the sensors 34 a and 34 b . In addition, the measurement completion notification data transmitted from the information processing unit 54 is received by the corresponding sample transport apparatus. At this time, the sample transport apparatus transmits transport instruction request data including the rack ID of the sample rack L to the system control apparatus 8 . When receiving the transport instruction request data (Step S 191 ), the CPU 81 a of the system control apparatus 8 searches the analysis result corresponding to the rack ID which is included in the transport instruction request data from the hard disk 81 d (Step S 192 ). The CPU 81 a determines whether a sample requiring remeasurement or a microscopic test is included in the samples held in the sample rack L (Step S 193 ). When determining that a sample requiring remeasurement or a microscopic test is not included (NO in Step S 193 ), the CPU 81 a decides the sample recovery unit 24 as the transport destination of the sample rack L (Step S 194 ). When determining that a sample requiring remeasurement or a microscopic test is included (YES in Step S 193 ), the CPU 81 a determines whether trouble information is received (Step S 195 ). When determining that the trouble information is not received (NO in Step S 195 ), the CPU 81 a advances the process to Step S 198 . When determining that the trouble information is received (YES in Step S 195 ), the CPU 81 a determines whether the sample rack can be transported to the smear preparation apparatus 6 or the measuring unit capable of performing remeasurement of the sample in the sample rack L (Step S 196 ). In greater detail, when trouble occurs in the sample transport apparatus 3 b , measurement is performed in the sample rack L by the measuring unit 51 and a sample requiring remeasurement by the measuring unit 52 or 53 is included, the CPU 81 a determines that the sample rack L cannot be transported to any measuring unit. When determining that the sample rack L cannot be transported to the smear preparation apparatus 6 or the measuring unit capable of performing remeasurement (NO in Step S 196 ), the CPU 81 a decides the sample recovery unit 23 as the transport destination of the sample rack L (Step S 197 ). When determining that the sample rack L can be transported to the smear preparation apparatus 6 or the measuring unit capable of performing remeasurement (YES in Step S 196 ), the CPU 81 a decides the smear preparation apparatus 6 or the measuring unit as the transport destination (Step S 198 ). After decision of the transport destination of the sample rack L as described above, the CPU 81 a transmits transport instruction data showing an instruction for transporting the sample rack L to the decided transport destination to the sample insertion and recovery apparatus 2 and the sample transport apparatuses 3 a , 3 b and 3 c (Step S 199 ) and ends the process. <Second Transport Operation of Sample Transport Apparatuses 3 a , 3 b and 3 c> FIG. 18 is a flowchart showing the flow of a second transport operation of the sample transport apparatuses 3 a , 3 b and 3 c . As described above, when the sample rack L is transferred to the post-analysis rack holding section 34 by the rack output section 39 , the sample rack L is detected by the rack sensor (Step S 211 ). In addition, when the sample rack L is transferred to the post-analysis rack holding section 34 by the rack output section 39 , the measurement completion notification data which is transmitted from the information processing unit 54 is received (Step S 212 ). The control section 32 detects the sample rack L in the post-analysis rack holding section 34 by the rack sensors. When receiving the measurement completion notification data from the information processing unit 54 , the control section executes the process of Step S 213 . In Step S 213 , the control section 32 transmits transport instruction request data including the rack ID of the sample rack L to the system control apparatus 8 (Step S 213 ). As described above, when receiving the transport instruction request data, the system control apparatus 8 decides the transport destination of the sample rack L and transmits transport instruction data for transporting the sample rack L to the transport destination to the sample transport apparatuses 3 a , 3 b and 3 c . The control section 32 waits to receive the transport instruction data (NO in Step S 214 ). When receiving the transport instruction data (YES in Step S 214 ), the control section determines whether the transport destination which is shown in the transport instruction data is the subsequent measuring unit or the smear preparation apparatus 6 or not (Step S 215 ). When the transport destination which is shown in the transport instruction data is the subsequent measuring unit or the smear preparation apparatus 6 (YES in Step S 215 ), the control section 32 controls the driving of the transport mechanism 31 , transfers the sample rack L to the rack overtaking transport section 321 by the rack feeding sections 33 b , and then discharges the sample rack L to the transport direction downstream side by the rack overtaking transport section 321 (Step S 216 ) and ends the process. In addition, when determining that the transport destination which is shown in the transport instruction data is not the subsequent measuring unit or the smear preparation apparatus 6 , that is, when determining that the transport destination is the sample recovery unit 23 or 24 (NO in Step S 215 ), the control section 32 controls the driving of the transport mechanism 31 , transfers the sample rack L to the rack return transport section 331 by the rack feeding sections 33 b , discharges the sample rack L to the preceding apparatus by the rack return transport section 331 (Step S 217 ) and ends the process. When the sample rack L is discharged to the apparatus on the transport direction upstream side from the rack return transport section 331 of the sample transport apparatus 3 b , 3 c or 4 , the apparatus introducing the sample rack L transports the sample rack L to the transport direction upstream side by the rack return transport section 331 and discharges the sample rack L to the apparatus on the upstream side. <Rack Sorting and Recovery Operation of Sample Insertion and Recovery Apparatus 2 > FIG. 19 is a flowchart showing the flow of a rack sorting and recovery operation of the sample insertion and recovery apparatus 2 . This rack sorting and recovery operation is an operation which is executed by the respective control sections of the sample insertion unit 21 and the sample recovery units 23 and 24 and is started by receiving the above-described transport instruction data from the system control apparatus 8 in Step S 221 . Hereinafter, the rack sorting and recovery operation will be described which is executed by the control section 23 a of the sample recovery unit 23 . When receiving the above-described transport instruction data from the system control apparatus 8 (Step S 221 ), the control section 23 a of the sample recovery unit 23 determines whether the transport destination of the sample rack L which is introduced into the second transport line 237 via the return line, the transport line 223 of the pre-processing unit 22 and the second transport line 217 is the sample recovery unit 23 on the basis of the transport instruction data (Step S 222 ). When determining that the transport destination is the sample recovery unit 23 (YES in Step S 222 ), the control section 23 a transfers the sample rack L introduced into the second transport line 237 to the rack placement section 231 by driving the rack transfer section 238 (Step S 223 ) and ends the process. In this manner, the sample rack L is recovered by the sample recovery unit 23 . When determining that the transport destination is not the sample recovery unit 23 (NO in Step S 222 ), the control section 23 a transports the sample rack L to the transport direction upstream side (X 2 direction) by driving the second transport line 237 and discharges the sample rack L to the second transport line 247 toward the sample recovery unit 24 (Step S 224 ). As described above, in the sample rack transport system 100 according to this embodiment, even when trouble occurs in one of the plurality of sample transport apparatuses 3 b , 3 c and 4 , excluding the sample transport apparatus 3 a on the most upstream side, the sample rack transport operation is not stopped in the entire system. Therefore, according to the sample rack transport system 100 according to this embodiment, sample measurement efficiency can be improved even when trouble occurs. When trouble is eliminated, a user is required to manually insert the sample rack L, in which necessary measurement has not yet been completed, into the sample insertion unit 21 . Here, in the sample rack transport system 100 according to this embodiment, the sample rack L is recovered by the sample recovery unit 23 adjacent to the sample insertion unit 21 . Accordingly, in the sample rack transport system 100 according to this embodiment, it is easy for the user to reinsert the sample rack L. (Second Embodiment) This embodiment is almost the same as the first embodiment. However, the configuration of a sample insertion and recovery apparatus 2 and the recovery destination of a sample rack L are different. FIG. 20 is a plan view of the sample insertion and recovery apparatus 2 according to this embodiment. As shown in FIG. 20 , the sample insertion and recovery apparatus 2 according to this embodiment includes a sample insertion unit 21 , a pre-processing unit 22 and a recovery unit 23 . In this embodiment, a sample rack L in which necessary measurement has not yet been completed is transported to the sample insertion unit 21 and a sample rack L in which necessary measurement has been completed is transported to the recovery unit 23 . When trouble is eliminated, a system control apparatus 8 transmits a transport instruction to the sample insertion and recovery apparatus 2 . Since the subsequent processes are the same as the processes of Steps S 103 to S 109 in the sample discharge operation of the sample insertion and recovery apparatus 2 in the first embodiment 1, the description thereof will be omitted. In a sample rack transport system 100 according to this embodiment, a sample rack L in which necessary measurement has not yet been completed can be automatically reinserted to the sample rack transport system 100 . Accordingly, it is possible to save the effort of reinsertion of the sample rack L into the sample rack transport system 100 by a user. (Other Embodiments) In the above-described embodiments, the computer 8 a of the system control apparatus 8 decides the recovery destination of a sample rack L and the control section of the sample recovery unit controls the operations of the rack transfer section and the second transport line on the basis of the decided recovery destination, and therefore, the sorting and recovery of the sample rack L is performed. However, the invention is not limited thereto. The sorting and recovery of the sample rack L may be performed by executing the process of deciding the recovery destination of the sample rack L and the process of controlling the operations of the rack transfer section and the second transport line with a single computer (control section). In the above-described embodiments, the configuration has been described in which the sample processing system 1 includes the blood cell analysis apparatus 5 which classifies blood cells included in a sample and counts the number of blood cells for each blood cell kind, but the invention is not limited thereto. The sample processing system may include a sample analysis apparatus other than the blood cell analysis apparatus, such as an immunological analysis apparatus, a blood coagulation measurement apparatus, a biochemical analysis apparatus and a urine analysis apparatus, and transport a blood sample or an urine sample to a measuring unit of the sample analysis apparatus. In the above-described embodiments, the configuration has been described in which the blood cell analysis apparatus 5 includes the three measuring units 51 , 52 and 53 and the information processing unit 54 , but the invention is not limited thereto. One or plural measuring units may be provided, and the measuring unit and the information processing unit may be formed integrally with each other. In addition, a configuration may be provided in which the mechanisms in the measuring units 51 , 52 and 53 are not controlled by the information processing unit 54 , but each of the measuring units has a control section formed of a CPU, a memory and the like so as to control the measuring units by the control sections, measurement data which is obtained by the respective measuring units is processed by the information processing unit and thus a sample analysis result is generated. In the above-described embodiments, the configuration has been described in which all the processes of the computer program 84 a are executed by the single computer 8 a , but the invention is not limited thereto. A distribution system may be provided which distributes the same processes as the above-described computer program 84 a to plural devices (computers) and executes the processes. In the above-described embodiments, as a concrete example, the case has been described in which trouble occurs in the sample transport apparatus 3 b . However, of course, the sample rack transport system 100 according to the above-described embodiment executes the same process even when trouble occurs in the sample transport apparatus 3 c. In a case in which trouble occurs in the sample transport apparatus 3 c when the sample recovery unit 23 is decided as the transport destination of a sample rack L in the first transport instruction of the system control apparatus 8 , the sample rack L may be discharged to the sample transport apparatus 3 a from the pre-processing unit 22 and the sample transport apparatus 3 a may transfer the sample rack L output from the sample insertion and recovery apparatus 2 to the rack overtaking position 321 a , transfer the sample rack to the rack return position 331 a by the rack feeding mechanisms 34 c and discharge the sample rack to the sample insertion and recovery apparatus 2 by the rack transport section 35 . In the above-described embodiments, when DIFF is included in measurement items of the measurement order of a sample held in a sample rack L and trouble occurs in the sample transport apparatus 3 b , the sample recovery unit 23 is decided as the transport destination. However, the invention is not limited thereto. For example, when CBC and DIFF are included in measurement items of the measurement order of a sample held in a sample rack L, the measuring unit 51 may be decided as the transport destination of the sample rack L. In this case, only CBC may be measured in the measuring unit 51 and then the sample recovery unit 23 may be decided as the transport destination of the sample rack L by the system control apparatus 8 . In this manner, the measurement items which can be measured in the measuring unit are measured and thus sample processing efficiency can be improved. The same is also applied to a case in which trouble occurs in the sample transport apparatus 3 c when RET and CBC or DIFF are included in measurement items of the measurement order of a sample held in a sample rack L. The trouble in the above-described embodiments is a severe problem which requires repair by a service man, but the invention is not limited thereto. The trouble may be a small problem such as a mistake in the transport of a sample rack. In the above-described embodiments, the sample transport apparatuses 3 a , 3 b and 3 c includes the rack overtaking transport section 321 which transports a sample rack L by driving the transport belt in the transport downstream direction with a stepping motor and the rack return transport section 331 which transports a sample rack L by driving the transport belt in the transport upstream direction with the stepping motor. However, the invention is not limited thereto. For example, a configuration may be provided in which the sample transport apparatuses 3 a , 3 b , 3 c and 4 have a transport belt and a stepping motor driving the transport belt to transport a sample rack by a single transport section which can switch the driving direction of the transport belt into the transport downstream direction and the transport upstream direction. In this case, a sample rack L which is determined that there is a measuring unit to which the sample rack can be transported by the system control apparatus 8 is discharged to the sample transport apparatus 3 a by the pre-processing unit 22 , is transported to the pre-analysis rack output position 323 by the transport belt which is driven in the transport downstream direction, and is fed to the pre-analysis rack holding section 33 by the rack feeding sections 33 b . When the measurement is completed, the sample rack L is fed to the rack overtaking position 321 a from the post-analysis rack holding section 34 by the rack feeding mechanisms 34 c and is transported to the rack recovery unit 24 by the transport belt which is driven in the transport upstream direction. On the other hand, a sample rack L which is determined that there is no measuring unit to which the sample rack can be transported by the system control apparatus 8 is discharged to the sample transport apparatus 3 a by the pre-processing unit 22 first, and is transported to the rack recovery section 23 by the transport belt which is driven in the transport upstream direction. Here, the sample rack L which is determined that there is no measuring unit to which the sample rack can be transported by the system control apparatus 8 may be directly transported to the rack recovery section 23 from the pre-processing unit 22 . In the above-described embodiments, each of the sample transport apparatuses 3 a , 3 b and 3 c includes both of the rack overtaking transport section 321 transporting a rack to the downstream and the rack return transport section 331 transporting a rack to the upstream. However, the invention is not limited thereto. For example, each of the sample transport apparatuses 3 a , 3 b and 3 c may include a unit which has a mechanism transporting a rack to the upstream and a unit which has a mechanism transporting a rack to the downstream. That is, a configuration may be provided in which each of the sample transport apparatuses 3 a , 3 b and 3 c includes a first sample transport unit having at least the rack overtaking transport section 321 and a second sample transport unit having at least the rack return transport section 331 . In the above-described embodiments, when determining that the inserted sample rack L cannot be transported to the transport destination in Step S 143 , the CPU 81 a changes the transport destination of the sample rack L to the sample recovery unit 23 , but the invention is not limited thereto. In the invention, the CPU 81 a may change the transport destination of the inserted sample rack L to another measuring unit which can perform measurement on the sample rack L. For example, when the measuring unit 53 is decided as the transport destination before the insertion of the sample rack L into the sample transport apparatus and trouble occurs in the sample transport apparatus 3 c corresponding to the measuring unit 53 after insertion of the sample rack L, the CPU 81 a may change the transport destination of the sample rack L, for which the measuring unit 53 is decided as the transport destination, to either of the measuring units 51 and 52 which can measure the sample in the sample rack L.

A sample processing apparatus comprising: a plurality of testing units arranged along a transport path and each configured to perform at least one type of test; a plurality of transport units configured to collectively constitute the transport path and collectively function to deliver samples to the plurality of testing units for testing; and at least one processor of a computer system and at least one memory that stores programs executable by the at least one processor to: (a) determine a type of test required to be performed on a sample; (b) if a trouble of a transport unit is reported, determine whether there is an available testing unit performable of the required type of test to which the sample is deliverable; (c) if there is the available testing unit, instruct to transport the sample to the available testing unit.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus that provide for the controlled delivery of a liquid to a patient. In particular, the invention relates to the controlled delivery of a liquid, preferably including a medication, into a patient with an infusion pump that is operated by gas pressure. 2. Description of the Prior Art The controlled delivery of liquids, particularly those containing medications, to patients has received substantial attention in the medical arts. The concept of drug infusion is that a patient can be given a medication over a given, relatively prolonged, time period. In this manner, the need for repeated injections is eliminated and there is a reduced risk of a development of drug sensitivities. Moreover, it is widely believed that sustained treatment with a drug is generally more effective than single bolus treatment. Further, infusion pump type devices allow for ambulatory treatment of a patient; i.e., the patient need not be attached to an intravenous ("IV") stand and bag. There have been a number of products in the past which have been useful for delivering liquids, such as medications, at a controlled flow rate. A typical example, which has been quite successful commercially, is illustrated in U.S. Pat. No. 5,080,652 to Sancoff et al. There has been a tendency for the art to focus on ambulatory care concerns. For example, many devices have been developed primarily for use by a patient. The patient can administer the drug to themselves over a prolonged time period without a hospital stay. Less emphasis has been directed to institutional use (such as use in hospitals). However, for the most part, these devices have failed to provide for an important need of such institutions where long-term storage and subsequent ready availability of medications is important. Devices such as the previously mentioned Sancoff et al. product have been designed and intended for use shortly after preparation. The devices are filled and soon thereafter connected to the patient, usually through an intravenous tube, and the medication is then administered to the patient by the fluid flow and metering components of the particular device. For instance, in the above-mentioned Sancoff et al. device, the liquid is dispensed or delivered from the device through the action of elasticized membranes which push the liquid containing the medication from the device to the patient. Other products from the prior art use compressed gas to force the medication or other liquid from a container. See, for example, U.S. Pat. No. 5,106,374 to Apperson et al. Such products, while useful for their purpose of prompt administration of medication to patients, are not amenable to preparation and extended storage of medication for subsequent use. In devices where the medication or other liquid is under constant pressure for an extended period of time, as from a compressed gas or a stressed resilient membrane, the pressure tends to drop, as the elastic material loses resiliency or as the compressed gas reacts with the liquid or leaks from the container. Further, such devices generally require complicated valving to retain the liquid under pressure and prevent leakage, which adds significantly to the cost and complexity of the individual products. Other devices have attempted to circumvent these problems by requiring pressurization at the time that the device is intended to be used. Such devices, however, have been cumbersome and not readily usable. They normally require an external source of pressurization such as attachment to a carbon dioxide cartridge or other outside gas generation equipment. It is time-consuming to obtain such equipment, to connect it to the device, and to wait for the pressurization to be completed. Where medication is needed quickly, the time delay can present a significant danger to a patient. The prior art has also attempted to make use of on-the-spot gas generation through the use of the reaction of chemicals that generate gas upon contact. See, for example, U.S. Pat. No. 3,023,750, to Baron. The generated gas, then, was used to force a liquid from a bag for delivery to a patient. However, this invention fails to provide the control that is essential to infusion. Gas is generated very rapidly, causing rapid flow rates and high pressure. A variety of patents for spray type canisters have used chemical reactions to generate a gas for a propellant to drive a liquid component from the canister as an aerosol. In order to avoid the depletion of the reactants, the prior art placed individual tabs of reactants in a plurality of sealed pouches. Over time, the pouches would sequentially dissolve and cause a new reaction to generate additional gas for producing the aerosol. However, this technology would be severely inadequate for use in infusion. Large fluctuations of the pressure inside the canister has been found to render these inventions unsuitable for infusion. It would therefore be advantageous to have a liquid delivery unit, particularly one for dispensing medications, that can be prepared for use and thereafter have a long storage life without pressurization. In this way, there would be little or no tendency for leakage of the medication or other liquid or loss of pressure potential. It would be additionally advantageous to provide a means for quickly and easily creating a gas propellant which would cause the liquid to be delivered in a controlled manner when and as needed. SUMMARY OF THE INVENTION The invention herein is a device which is uniquely suited to meet the requirements of hospitals and other institutions. These organizations need to have products which can retain liquids such as medications in usable form over an extended shelf life without leakage or loss of ability to be rapidly and thoroughly dispensed, and which can be activated for such dispensing quickly and without the need for additional equipment (such as pressurized gas cylinders) to effect the activation. Unlike prior art devices, which had to be activated initially (and then suffer short shelf life) or which required complicated and time consuming methods of subsequent activation, the present device remains inert and ready for use for long periods and then can be quickly and easily activated whenever needed. In accordance with a first aspect of the present invention, there is provided a controllable liquid delivery device comprising a hollow casing having a fluid impermeable wall, an inner surface of the wall surrounding and forming an open interior of the casing, a flexible fluid impermeable membrane disposed within the interior and separating a liquid chamber from a propellant chamber, a liquid filling the liquid chamber, an outlet port through the wall providing fluid communication between the liquid chamber and the exterior of the casing, first and second chemicals separately disposed in the propellant chamber, the first and second chemicals reactive with each other such that upon contact the first and second chemicals react to generate a quantity of propellant gas, means for controlling the rate at which the first and second chemicals generate the propellant gas, barrier means initially separating the chemicals, and means operable to allow one of the chemicals to pass through the barrier means and come into contact with the other of the chemicals, whereby, upon activation of the contacting means, the first and second chemicals react to generate the propellant gas, the propellant gas thereupon expanding against the membrane and causing the membrane to move against the liquid, causing the expulsion of the liquid from the liquid chamber. In a preferred embodiment of the device, the casing comprises a pair of shells of substantially equal volume and shape which are sealingly joined through the respective bases thereof to form the casing. In another embodiment, a peripheral edge portion of the membrane is retained between the bases of the shells. In yet another embodiment, each shell has a radially disposed flange extending from the base, the flanges cooperating to form the sealable joint between the shells. In another embodiment, the peripheral edge portion of the membrane is retained between the flanges of the bases of the shells. In still another embodiment, the membrane has a surface area of at least about one-half the surface area of the interior of the casing. In another embodiment, the membrane, prior to the reaction of the first and second chemicals, is disposed substantially within the propellant chamber. In another embodiment, the membrane, following substantially complete reaction of the chemicals, is disposed substantially within the liquid chamber. In still another embodiment, the first chemical is in liquid form. In another embodiment, the second chemical is in liquid form. In another embodiment, the second chemical is in solid form. One of the chemicals is preferably selected from the group consisting of carbonates and bicarbonates, preferably, Group I and II metal carbonates and bicarbonates, even more preferably, sodium bicarbonate, sodium carbonate and calcium carbonate. In a preferred embodiment, one of the chemicals is selected from the group consisting of acids, acid anhydrides, and acid salts, such as, citric acid, acetic anhydride, and sodium bisulfate. Preferably, the first chemical is a citric acid solution and the second chemical is sodium carbonate. In this embodiment, the sodium carbonate is preferably in solid form. In a preferred embodiment, the barrier means comprises a container in which the citric acid solution is contained and breaching the container permits the citric acid solution to come into contact with the sodium carbonate. In another preferred embodiment, the controlling means comprises a third chemical moiety that slows the reaction between the first and second chemicals. In another embodiment, the controlling means comprises a physical barrier acting to limit the contact between the first and second chemicals, thereby slowing their reaction. In another embodiment, the controlling function is accomplished by a relief valve in fluid communication with the propellant chamber adapted for allowing for the escape of gas when a pressure generated by the reaction between the first and second chemical exceeds a predetermined level. In a highly preferred embodiment, a combination of third chemicals, geometric configurations, and a relief valve are used to accomplish the control function. In accordance with another aspect of the present invention, there is provided a method to deliver a liquid from a container which comprises providing a hollow casing having a fluid impermeable wall, a flexible fluid impermeable membrane disposed within the interior of the hollow casing and dividing the interior into a propellant chamber and a liquid chamber containing a liquid, an outlet port through the wall providing fluid communication between the liquid chamber and the exterior of the casing, first and second chemicals disposed in the propellant chamber, the first and second chemicals reactive with each other upon contact to form a quantity of propellant gas, means for controlling the rate at which the first and second chemicals generate the propellant gas, barrier means initially separating the chemicals, means operable to allow one of the chemicals to pass through the barrier means and come into contact with the other of the chemicals, activating the contact means and causing the first and second chemicals to come into contact and react to form the propellant gas, and causing the propellant gas to expand against the membrane and cause the membrane to move and enlarge the volume of the propellant chamber, decrease the volume of the liquid chamber, and expel the liquid contained in the liquid chamber from the liquid chamber through the outlet port. In the method, the casing preferably comprises a pair of shells of substantially equal volume and shape which are sealingly joined through the respective bases thereof to form the casing. In another embodiment, a peripheral edge portion of the membrane is retained between the bases of the shells. In another embodiment, each shell has a radially disposed flange extending from the base, the flanges cooperating to form the sealable joint between the shells. In another embodiment, the peripheral edge portion of the membrane is retained between the flanges of the bases of the shells. In another embodiment, the membrane has a surface area of at least about one-half the surface area of the interior of the casing. In another embodiment, the membrane, prior to the reaction of the first and second chemicals, is disposed substantially within the propellant chamber. In another embodiment, the membrane, following substantially complete reaction of the chemicals, is disposed substantially within the liquid chamber. In a preferred embodiment, the first chemical is in liquid form. In another preferred embodiment, the second chemical is in liquid form. In another highly preferred embodiment, the second chemical is in solid form. Preferably, one of the chemicals is selected from the group consisting of carbonates and bicarbonates, particularly, Group I and II metal carbonates and bicarbonates, and sodium bicarbonate, sodium carbonate and calcium carbonate are highly preferred. In a preferred embodiment, one of the chemicals is selected from the group consisting of acids, acid anhydrides and acid salts, preferably, citric acid, acetic anhydride and sodium bisulfate. In a highly preferred embodiment, the first chemical is a citric acid solution and the second chemical is sodium carbonate. In this embodiment, the sodium carbonate is in solid form. In another embodiment, the barrier means comprises a container in which the citric acid solution is contained and breaching the container permits the citric acid solution to come into contact with the sodium carbonate. In another embodiment, the controlling means comprises a third chemical moiety that slows the reaction between the first and second chemicals. In another embodiment, the controlling means comprises a physical barrier acting to limit the contact between the first and second chemicals, thereby slowing their reaction. In accordance with another aspect of the present invention, there is provided a method to generate gas for the controlled delivery of a liquid from a container, comprising separately providing a first and a second chemical, at least one of the chemicals enclosed in a first container, the first and second chemicals being reactive to generate a gas upon contact therebetween, providing means for controlling the reaction rate between the first and second chemicals, and means operable to allow the chemicals to come into contact with one another, activating the contact means so that the first and second chemicals come into contact and react to generate a gas, the controlling means acting to regulate the reaction between the first and second chemical such that the rate at which the gas is generated is substantially linear, and communicating the gas to means operative to drive a liquid from a second container. In a preferred embodiment, the controlling means is accomplished through the geometric shape of one of the first or second chemicals. In another embodiment, the controlling means is accomplished through the addition of a substantially nonreactive filler. In another embodiment, the controlling means is accomplished through selectively blocking one of the first and second chemicals from reaction with the other of the first and second chemicals. In another embodiment, the controlling means is accomplished through use of a relief valve. In accordance with another aspect of the present invention, there is provided an apparatus for the generation of a gas for use in a gas driven pump, comprising a first container that is adapted to be situated in fluid communication with the pump, the first container being adapted to separately contain a first and a second chemical as chemical reactants, the first and second chemicals being reactive upon mixing to generate a gas, such that when the first and second chemical are mixed and a gas is generated in the reaction thereof, the apparatus further comprising means for allowing the gas to be communicated from the first container to the pump while the chemical reactants remain in the container. In a preferred embodiment, the means comprise hydrophobic containment means. In such embodiment, the hydrophobic containment means is preferably a polymeric material, and is advantageously a polypropylene material. Preferably, the hydrophobic containment means is a membrane selected from the group consisting of Tyvek®, Versapel®, Goretex®, Celguard 2400™, Porex®, and BMF™. In a preferred embodiment, the first chemical is provided as a solution or liquid and the apparatus further comprises a rupturable membrane surrounding the first chemical, such that when the rupturable membrane is ruptured, the first chemical is released and mixes with the second chemical. In another embodiment, the first chemical is provided as a solution or liquid and the apparatus further comprises a rupturable membrane surrounding the second chemical, such that when the rupturable membrane is ruptured, the second chemical is released and mixes with the first chemical. In another embodiment, the hydrophobic containment means is a membrane forming a first pouch, the first pouch forming a second pouch surrounding the first chemical and a third pouch surrounding the second chemical and further comprising means therebetween that is adapted to be opened to allow the first and second chemical to mix. In another embodiment, the first pouch further comprises an internal wall and the second and third pouch are formed by reversibly closing the internal wall of the first pouch upon itself. In another embodiment, the internal wall of the membrane is closed by twisting the first pouch and the first and second chemical are allowed to mix by untwisting the membrane. In accordance with another aspect of the present invention, there is provided a method to generate gas for the controlled delivery of a liquid from a container, comprising separately providing a first and a second chemical, at least one of the chemicals enclosed in a first container, the first and second chemicals being reactive to generate a gas upon contact therebetween, providing means for controlling the reaction rate between the first and second chemicals, and means operable to allow the chemicals to come into contact with one another, activating the contact means so that the first and second chemicals come into contact and react to generate a gas, the controlling means acting to regulate the reaction between the first and second chemical such that upon attainment of a predetermined pressure within the first container, the container is maintained at the predetermined pressure, and communicating the gas to means operative to drive a liquid from a second container at a substantially linear flow rate. In a preferred embodiment, the controlling means is accomplished through use of a pressure relief valve. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a graph showing the pressure developed over time in three different reactions of sodium carbonate (Na 2 CO 3 ) and citric acid (C 6 H 8 O 7 ; 2-hydroxy-1,2,3-propanetricarboxylic acid): (i) pelletized sodium carbonate, (ii) pelletized sodium carbonate bound with a filler, and (iii) pelletized sodium carbonate bound with a filler and covered with a room temperature vulcanizing (RTV) silicone adhesive sealant on the top and the bottom of the pellet. FIGS. 2A and 2B illustrate two alternate preferred embodiments of the solid reactant of the present invention. FIGS. 3 through 6 are a series of cross-sectional drawings of the device, showing its initial condition and condition at steps during pressurization and dispensing of the contained liquid. FIG. 7 is a cross-sectional detailed view illustrating an alternative form of construction of a portion of the device. FIGS. 8A and 8B show, respectively, an embodiment of a cap for the device and such cap in use with a liquid distribution tube. FIG. 9 illustrates typical components in the fluid outflow line for controlling flow and filtering the liquid. FIG. 10 is a partial cross-sectional view showing an alternative embodiment of the chemical container. FIGS. 11 and 12 are respectively a perspective view and a cross-sectional side elevation view of an alternative embodiment of the device of this invention. FIGS. 13 and 14 are cross-sectional views of a portion of the device illustrating alternative means for joining the two halves of the device and securing the membrane. FIG. 15 is a cross-sectional view of another embodiment of the device of this invention, illustrating another embodiment of the chemical container and the presence of an optional relief valve. FIGS. 16 and 17 are respectively the sectional side elevation view and the sectional top plan view, each sectioned along its mid-line, of another embodiment of the device of this invention. FIGS. 18 and 19 are cross-sectional side views of a preferred device in accordance with the present invention taken along line 18--18 in FIG. 16. FIG. 20 is a schematic of a preferred pressure relief valve in accordance with the present invention. FIG. 21 is a graph showing the flow rate over time obtained in a device through the use of the reactants shown in connection with FIG. 1 (iii) and the pressure relief valve of FIG. 20. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS We have surprisingly discovered that it is possible to make a device that provides controlled liquid delivery over time that can be prepared for use and thereafter have a long storage life without pressurization. In this way, there is very little tendency for leakage of the medication or other liquid or loss of the unit's pressure potential. The device in accordance with the present invention additionally provides a means for quickly and easily creating a gas propellant that causes the liquid to be delivered in a controlled manner when, and as, needed. The basic aspects of the invention that obtain these aforementioned advantages arise from the use of a controlled chemical reaction that evolves gas. The chemical reaction is started by an operator of the device, when needed. The gas evolution reaction occurs in a container and the gas evolved operates to apply pressure on a liquid separated from the gas evolution reaction. It is preferable, indeed arguably necessary, that the gas evolution reaction be separated from the liquid to be infused into a patient, since, often the chemicals used in the gas evolution reaction or the byproducts from the reaction are toxic and/or undesirable for administration to a patient. In either case, it will be understood that the pressure exerted on the liquid will force the liquid out of a port at a flow rate that is proportional to the rate of the gas evolution reaction. Referring now to FIG. 1, there is provided a graph showing the pressure developed over time in three different reactions of sodium carbonate (Na 2 CO 3 ) and citric acid (C 6 H 8 O 7 ; 2-hydroxy-1,2,3-propanetricarboxylic acid): (i) pelletized sodium carbonate, (ii) pelletized sodium carbonate bound with a filler, and (iii) pelletized sodium carbonate bound with a filler and strips covered with a room temperature vulcanizing (RTV) silicone adhesive sealant. In each of the reactions, a solution of citric acid (7.5 gm/15 ml (2.6M)) was reacted with 2.72 grams (0.025M) of sodium carbonate. Also, in each the sodium carbonate was formed into a "donut shaped" pellet (as shown in FIG. 2a) using a tablet or pill press. In reaction (ii), prior to making the pellet, 15% by weight of a filler, polyvinylpyrrolidone (PLASDONE, available from ISP Technologies, Inc., Wayne, N.J.), was added to the sodium carbonate. In reaction (iii), a similar pellet to that made for reaction (ii) was prepared containing the sodium carbonate and 15% by weight of the polyvinylpyrrolidone. This pellet was of the same geometry as that used in reactions (i) and (ii), however, a room temperature vulcanizing (RTV) silicone adhesive was applied to the top and bottom of the pellet, as shown in FIG. 2b, so as to reduce the surface area of the sodium carbonate and filler that would be exposed to the citric acid solution. In this particular reaction, the RTV was PERMATEX®, available from Loctite Corporation, Cleveland, Ohio (Part No. 66B). In order to run the reactions, a sealable container was used which allowed for the displacement of a liquid therefrom. The container is made up of a first container which encloses a liquid. Also contained in the container is a second container that holds the citric acid solution. Thus, when the pellets are immersed in the citric acid solution in the second container, the liquid in the first container will be displaced and its flow rate and pressure over time can be measured. Even in this very rudimentary test, it will be appreciated that without the use of a controlling agent (i.e., in reaction (i) where the sodium carbonate is reacted neat with the citric acid solution), liquid is forced out at too rapid a rate in the early stage of the reaction to act effectively in an infusion pump. Then, the reaction slows down and flow rates become very slow. An infusion pump must provide a relatively constant flow rate over time. This is not achieved where the reactants are reacted neat. The use of a controlling agent, configurations, and/or controlling mechanisms, on the other hand, can be used to flatten the curve of flow rate or pressure generated over time, as seen in the results from reactions (ii) and (iii). The present invention contemplates the use of a variety of controlling agents. Virtually any material, geometry, or enclosure that acts to limit the contact between two reactants can act as a controlling agent for the purposes of the present invention. For example, as mentioned, fillers are quite effective, such as polyvinylpyrrolidone (i.e., Plasdone, mentioned above), polyethylene glycol (i.e., PEG 400 available from Olin Corp., Stamford, Conn.), and polyvinyl alcohol (i.e., PVA 205S available from Air Products, Allentown, Pa.). Similarly, there are a large number of excipients or carriers that will act to slow the chemical reaction. Further, a variety of geometries or enclosures can also be used that limit the rate at which gas is generated from the reaction. For instance, a reactant can be partially enclosed in a completely or partially insoluble material, such that only a limited surface area of one reactant is available for reaction. This is accomplished in a preferred embodiment through the use of the RTV agent, however, it will be understood that other insoluble materials, such as waxes, metal tubes, and other materials can also be used with similar success. Moreover, it will now be appreciated that the reaction rates of the chemical moieties can be tailored to meet a user's specific requirements. In other words, through arranging or allowing contact of the chemicals in a predetermined manner, a pressure profile can be generated. The pressure profile can, for example, start at an initial profile designed to deliver fluid from the pump at an initial slow rate and can, thereafter, increase, to deliver fluid at a second increased rate. This is advantageous in certain applications, such as delivery of cancer chemotherapeutic agents. Multiple stages of fluid delivery can be implemented through predetermination of a desired pressure profile and design of the chemical reactants' configurations or contact to achieve that profile. In simple embodiments, it will also be appreciated that it is possible through use of the present invention to make pumps that allow for the delivery of a variety of predetermined, constant flow rates. Pumps prepared in accordance with the present invention can be prepared to generate flow rates from as low or lower than 2 ml. per hour to upwards of 200 ml. per hour. Particularly preferred flow rates are in the range of from about 5, 10, 15, 20, 50, 100, 150, or 200 ml. per hour. Therefore, a pump can be prepared with sufficient chemical reactants to allow only a fluid flow rate of 5 or 10 ml. per hour. Or, the pumps can be similarly prepared to provide a flow rate of 15 or 20 ml. per hour. The specific quantities of reactants necessary to achieve desired flow rates will depend on the particular choice of the reactants and the pressure and/or flow rate profile desired. Such quantities will be determinable empirically by one of ordinary skill in the art in light of the present specification and without undue experimentation. With this background on the mechanisms used to controllably generate a gas in accordance with the present invention, we shall now turn to a discussion of the apparatus that can be used to contain the gas generation reactants and the liquid to be delivered, in such a manner that when the reaction is commenced, the liquid can be pumped from the apparatus to the patient in a controlled, safe, and sterile manner. One such device that fulfills the above objectives of the present invention can be understood by reference to the drawings, with initial reference to FIG. 3. The device 2, preferably is formed of a casing 4. The casing 4, can be formed of any suitable material and can be rigid, flexible, or otherwise, and may even be a substantially flexible material, such as in the case of materials used to manufacture IV bags. It will be appreciated that it is preferred to prepare the casing 4 of a substantially rigid material, because, there is less chance that the casing would rupture or unattractively expand and have increased durability. However, substantially flexible materials would nevertheless function equivalently. Moreover, such materials could advantageously be disposed within another outer casing to provide support and reduce concerns about rupture, expansion, or durability. In the embodiment pictured in FIG. 3, however, the casing 4 is prepared from a substantially rigid material and is conveniently formed in two halves 6 and 8. Any convenient shape of the casing 4 may be used, such as approximately spherical (so that halves 6 and 8 are essentially hemispheres) as shown in FIGS. 3-6, cylindrical with rounded edges (as shown in FIGS. 11-13), or a generally rectangular or cube shape with rounded edges and corners (as shown in FIGS. 16-17) as long as the shape is such that substantially all of the contained liquid will be dispensed and little or none will remain in the container after use, and that the desired external shape of the device can be maintained when the device is pressurized. (For brevity herein, reference to casing 4 shall include both halves 6 and 8 when the subject discussed is equally applicable to the entire casing 4. When individual halves 6 and 8 are to be discussed, they will identified separately. In any event the context will make it clear to the reader skilled in the art which reference is intended.) Halves 6 and 8 are normally of equal or substantially equal shape and volume. Forming the halves of significantly different shapes or volumes is to be avoided since the movement of membrane 18 and the efficient dispensing of the contained liquid will be hampered or prevented by such substantially unequal shapes or volumes. The membrane 18 is a flexible member that is essentially distended into the lower half 8 when filled by the liquid and becomes extended into the upper half 6 when the gas generating reaction forces liquid through the neck 28 of the device 2. Thus, the distension and extension of membrane 18 must not be hampered so that liquid can be delivered from the device to the patient. As will be appreciated, this function can be fulfilled by a variety of materials and structures, as will be discussed in greater detail below. The halves 6 and 8 are joined at their adjoining peripheries by any convenient sealing means. In FIGS. 3-6 and 11-12, the sealing means are opposed radial flanges 10 and 12, which in turn are locked together by an annular channel 14 (not shown in FIGS. 11-12). In FIGS. 13 and 14, alternatives are shown in which a projection on the face of one flange interfits or overlaps with a corresponding member on the face of the other flange, with the membrane being secured between the two faces. Preferably the projection and the corresponding member are continuous around the faces of the flanges. For instance, there may be an annular ring-and-groove structure as in FIG. 13, in which an annular ring 11 projects from the face of flange 10 and fits into a corresponding annular groove 13 in flange 12, or there may be a peripheral male-female fit as shown in FIG. 14, in which an annular lip 15 projects from the peripheral edge of flange 10 and extends outwardly over the outer periphery of flange 12. Annular ribs 17 (shown in the phantom view of the pre-compression position of flange 10 in FIG. 14) help retain the membrane in place and enhance the sealing effect of the flanges so that no fluid escapes or depressurization occurs through the joint between the flanges. The flanges may be joined in any convenient sealing manner. The sealing means may if desired be releasable, so that the device can be reused, by being disassembled and sterilized (with if desired replacement of the membrane) and then reassembled and refilled with a new liquid and new propellant chemicals. Bolts, clips, or other mechanical fasteners spaced apart around the flanges may be used for releasable sealing. For instance, the embodiment shown in FIGS. 3-6 contains a channel 14 to hold the two halves 6 and 8 together. Alternatively, if releasability is not desired, the halves of the device can be sealed by suitable adhesives applied to the flanges or by mechanical or thermal means such as ultrasonic or thermal welding of the mating surfaces of the flanges. For instance, in the embodiment shown in FIG. 7, flanges 10' and 12' each has a small shoulder (respectively 56 and 58) and their opposed surfaces are closely abutting. Those surfaces can then be joined as by an adhesive 60 or by ultrasonically, thermally, or frictionally welding to form a tight circumferential seal around the casing 4. Adhesive application or ultrasonic or thermal welding may occur only at points A (FIGS. 13 and 14) or the mating structures may be configured to have larger surface areas in contact for adhesion or welding as shown in FIG. 7. Those skilled in the art can readily determine the appropriate manner of sealing for the end use contemplated. Casing 4 has a relatively thin gas- and liquid-tight wall 16 which for the most part is rigid or semi-rigid. It will be typically be made of a plastic, polymeric, or hard rubber material, with the particular construction material being selected based upon the materials compatibility with the fluid contained. When liquid medications are to be contained, the casing 4 will be made of a material which can be sterilized (through heat, chemical treatment, or otherwise) and which is inert to the medication. The casing material may be transparent so that the liquid inside can be viewed, or it may be translucent or opaque. If transparent or translucent, it may also be tinted or otherwise chemically treated to avoid light degradation of the contained liquid. Many suitable materials contain ultraviolet light stabilizers or blockers that can act to protect the liquid contained therein from light degradation. The properties of such materials are widely described in the art and literature; see, e.g., Rubin, Handbook of Plastic Materials and Technology (John Wiley & Sons, Inc. (1990)) and Morton "Rubber Technology" (3d ed., Van Nostrand Reinhold Co. (1987)). Those skilled in the art will have no difficulty selecting suitable materials for various embodiments and uses of the device. Within the casing 4 is a flexible membrane 18 which is also gas- and liquid-tight and is shaped preferably to match the inner contours of wall 16 in either of the halves 6 or 8. As was mentioned above, the membrane essentially distends into the lower half 8 when filled by the liquid and becomes extended into the upper half 6 when the gas generating reaction forces liquid through the neck 28 of the device 2. Thus, the distension and extension of membrane 18 must not be hampered so that liquid can be delivered from the device to the patient. The surface area of the membrane 18 will normally be larger than the interior surface area of either of the halves 6 and 8 (or of the larger, if they are of different sizes), since it will also have a peripheral area 20 for retention between the flanges 10 and 12 and preferably will also have some degree of pleating to enhance its ability to move across the device under gas pressure. The membrane may be of a single layer of material as shown in FIGS. 3-7. Preferably, however, there will be two or more layers of material, as shown in FIGS. 14 and 15. Multiple layers provide a significant margin of safety, since a tear or leak in a single-layer membrane permits leakage of liquid, while even if there is a tear or leak in one layer of a multiple-layer membrane the remaining intact layers will safely retain the liquid. Further, since the membrane must have a certain thickness to withstand the gas pressure, a single-layer membrane must be of that overall thickness in the single layer, thus rendering it less flexible than a multi-layer membrane of the same overall thickness, since the thinner individual layers are separately more flexible. As will be mentioned below, the separate layers of a multi-layer membrane are preferably bonded only at their periphery, so that they can slide freely against each other as the membrane moves under the gas pressure and thus the membrane as a whole can flex easily across the interior of the device in response to the gas pressure. Membrane 18 can be made of a wide variety of polymeric materials, including various flexible plastics and rubbers. As with the casing materials, the properties of suitable membrane materials are widely described in the art and literature, including the aforementioned Rubin and Morton texts; again no difficulty will be had in selecting a suitable material. It is preferred that the membrane 18, while being flexible, have relatively minimal elasticity, since the membrane is intended to move the liquid through the interior of the casing. If the elasticity is too great, the membrane will stretch irregularly and some of the liquid may become trapped in folds of the stretched membrane. Initially the membrane 18 is positioned within (or distends into) half 8 as shown in FIG. 3 so that it substantially covers the inner surface of the half. The liquid 22 to be dispensed is contained in a "liquid chamber," i.e., that portion of the interior 24 of the casing 4 which is bounded by the inner surface of wall 16 in half 6 and the corresponding surface of membrane 18 as the latter lies against the inner surface of wall 16 in half 8. Neck 26 is formed in half 6 (preferably at the center of its wall 16). Neck 26 opens to the outlet port 28 through which the liquid 22 is dispensed, as will be described below. If desired, there may be a one-way valve 49 in neck 26 (FIG. 15) to prevent loss of any liquid 22 even if the outlet port 28 is not capped. The one-way valve 49 would be opened by pushing tubing or a similar object through the neck 26, in a similar manner to that shown in FIG. 8B. The device will contain some form of barrier to initially separate the two reactive chemicals. In the embodiment shown in FIGS. 3-6, the barrier is in the form of an openable gas- and liquid-tight container 30. Container 30 may, but need not, be positioned diametrically opposite from outlet port 28. In FIGS. 3-6 the container 30 is shown as positioned in a well 32 which is formed in the wall 16 of half 8. Alternatively, however, container 30 may be completely within half 8 as indicated in FIG. 10 at 30'. This latter configuration is less preferred, however, since it makes it more difficult to open the container 30, as will be described below. Membrane 18 is positioned between liquid 22 and container 30, and the space within the interior of the casing on the side of membrane 18 opposite to liquid 22 comprises a "propellant chamber" into which the propellant gas will be evolved as described below. If desired, there may be a small depression 34 formed near the midpoint of membrane 18 as indicated in FIG. 3, the purpose of which will be described hereafter. Membrane 18 and part of the wall 16 of half 8 cooperate to form a chamber 36. Container 30 may be either in chamber 36 or immediately adjoining it, as shown in FIGS. 3 and 10. The driving force for the expulsion of liquid 22 from the interior 24 of casing 4 is provided by a volume of gas which is evolved by the reaction of two chemicals, which as noted are kept separate from each other until the time at which the gas formation is desired. Considering the embodiment of FIGS. 3-6, one of the two chemical reactants will be contained initially within container 30. For ease of description herein, the chemical reactant contained in container 30 will sometimes be referred as the "first" reactant and the other chemical reactant, initially kept separate from container 30 (or separated within container 30), will be referred to as the "second" reactant. Both chemicals must be substantially inert toward the membrane 18, casing 4 and container 30 and stable throughout the entire expected shelf life and service life of the product. They will, however, be readily and controllably reactive with each other under ambient conditions, preferably simply upon contact. In a preferred embodiment, one of the reactants will be a carbonate or bicarbonate compound, particularly preferred being Na 2 CO 3 (known as soda ash in some of its commercial forms) and CaCO 3 ; compounds like NaHCO 3 may also be used but one must be careful to keep them below the temperature at which they exhibit significant decomposition (such as NaHCO 3 , which begins to evolve CO 2 gas at temperatures above about 45° C.). In the same preferred embodiment, the other reactant is preferably an inorganic acid, an acid anhydride, or an acid salt. Typical preferred examples of each are citric acid, acetic acid anhydride, and sodium bisulfate. Stronger acids such as HCl or HNO 3 or weaker acids such as acetic acid may also be used. The most preferred combination is considered to be sodium carbonate and citric acid, both of which are quite stable but which react to evolve CO 2 gas upon contact. In most cases, it will not matter which is considered the first reactant and which is considered the second reactant. Generally, however, as will be appreciated, one of the reactants will be a liquid (or in solution), and the other reactant, either as a solid, liquid, or in solution. This helps to ensure that the two reactants can mix and react, Either one chemical itself may be a liquid or one of the chemicals may be dissolved or dispersed in a liquid carrier or solvent, preferably water. In a preferred embodiment, a citric acid solution and a solid sodium carbonate are used for the gas generation. Therefore, those skilled in the art can readily select and designate the particular materials to be used depending on ease of handling, speed of reaction, inertness toward the other materials of the system and so on. However, as was discussed above, a critical aspect of the present invention is the controllable release of gas. In FIG. 1, the superiority, in terms of almost linear liquid delivery is seen when a control agent is incorporated with one of the reactants. It is preferred that the two reactants fully react with each other on contact, however, where the reactants are relatively slow in reacting or in generating gas, it is also possible to include a catalyst (as a third component) to promote or accelerate the reaction. This is less preferred, however, since it complicates the system and adds to the cost. Initially such catalyst will be disposed separately with one or the other of the reactants, with the disposition chosen to minimize any potential for the catalyst to react prematurely with the single reactant it is in contact with. In a preferred embodiment, the system comprises a liquid reactant and a solid reactant. The liquid reactant 40 will normally be retained in the chamber 36. The reactant 38 in chamber 30 may either be in liquid form or in dry form, and usually is in the form of dry powder, granules or one or more porous pellets to provide an extended surface area to increase the rate of contact and reaction. There are several types of barriers which can be used to separate the chemicals 38 and 40 until the device is to be used, but which can be breached to permit the chemicals to mix to generate the gas 42. Where the barrier is in the form of container 30, it may be made of a breakable material, such as thin glass or thin brittle plastic, which can be easily broken to allow the chemicals to mix. For instance, if the casing material in the area of well 30 has some degree of flexibility and the container 30 is sized to abut the inner wall of well 32 as shown in FIG. 3, a modest squeezing of the outside of the well 32 by simple finger pressure will cause the container 30 to fracture and allow the chemicals to mix. In the alternate configuration shown in FIG. 10, where there is no well 32 and the container 30' is within chamber 36, a small rubber self-sealing membrane or grommet 44 is mounted through the wall 16 of half 8 so that a long sharp object such as a needle can be inserted through grommet 44 to contact and fracture container 30'. Yet another embodiment is shown in FIG. 15, in which the bottom of well 32 is in the form of a flexible cap or dome 23 with a spike or similar piercing device 25 mounted on its inside. The barrier is in the form of a perforable membrane 27 which is mounted across the base of the dome portion 23 of the well 32, to form a liquid-tight chamber 29 under the dome, with the liquid chemical 40 initially retained in the chamber 29 and isolated from the other chemical 38 which is positioned in the remaining portion of the well 32. When the flexible dome 23 is depressed by the user's fingers, the spike 25 penetrates and perforates the membrane 27 and the liquid chemical 40 flows into the rest of well 32 and contacts the other chemical 38 (here shown in a pellet form) in container 30, causing the gas-generation reaction. If desired, porous sponges or similar liquid retaining and dispersing means 31 may be used to cause the liquid chemical 40 to flow throughout the container 30 in a controlled and directed manner. A screen or perforated plate 35 having openings 33 may be used to retain the solid materials in container 30 but allow the evolved gas 42 to pass freely out of the well 32 and into contact with membrane 18. In yet another embodiment also indicated in FIG. 10, one may dispense with a container and have the first chemical 38 contained in a separate syringe 46, the needle 48 of which can be inserted through the barrier 44 (in the form of a membrane or grommet) so that the liquid chemical 40 can be injected into the other chemical 38 within the chamber 36. This configuration is not preferred, however, because it requires two separate components (albeit that they may be kept together as a single package). In addition, it is much less rapid to use than simply having a breakable container 30 such as in FIG. 3. As will be evident from FIGS. 15-17, that portion of the propellant chamber 36 in which the chemicals are initially housed may be spaced adjacent to or spaced apart from the portion which is adjacent to the membrane 18 and into which the gas evolves. In such case the two portions (designated 36a and 36b) will be connected by a conduit 51 for the gas to pass from the reacting chemicals into contact with membrane 18. The conduit may be in a tube form as shown in FIGS. 16 and 17, or it may simply be a screened opening as shown in FIG. 15. Hook or hole 35 may be provided to enable the device 2 to be hung from a hospital pole or similar suspending hook. If a hook 35 is used with the configuration shown in FIG. 10, membrane 44 will have to be positioned so as not to interfere with the hook 35. The device may also have an exterior rigid skirt 47 to allow it to be placed in standing position on a shelf for storage, and to protect the well 32 or dome 23 from accidental contacts which would cause the barrier 27 to be breached and the device inadvertently activated and to protect relief valve 45 (if present) from damage. The operation of the device will be evident from the FIGURES. The barrier (e.g., container 30 or a membrane (not pictured)) is first breached so that the liquid chemical 40 quickly flows into the interior of container 30, contacting chemical 38 and reacting as indicated at 38'. As noted above, the breaching may be by breakage of container 30, as illustrated in FIGS. 4-6, so that the liquid chemical 40 flows into the fractured container 30 via openings 50. Alternatively, as shown in FIG. 13, breaching may be by perforation of a membrane between the two chemicals. In the embodiment shown in FIG. 13, pressure on the dome not only causes the membrane to be perforated, but it also causes the liquid chemical 40 to be forced into contact with the other chemical 38, thus augmenting the normal tendency of the chemical 40 to flow of its own accord. This forcing will also be advantageous when the device is mounted with the well in a downward or sideways position where normal flow would be limited or prevented. The reaction between chemical reactants 38 and 40 results in rapid evolution of gas 42 which initially moves as bubbles through the liquid. At the time of FIG. 4, the reaction of the two chemicals 38 and 40 has just started and there is not yet enough evolved gas 42 to cause the membrane 18 to move. As the gas 42 is evolved it moves through the liquid and begins to concentrate under membrane 18. As more gas is evolved, it causes the membrane 18 to move so that the membrane 18 travel is uniform along the diametrical axis of the casing 4 between the well 32 and the outlet port 28. As noted above, it may be desired to have a depression 34 present in which the gas initially evolved can concentrate, thus causing the middle of the membrane 18 to move first, with the depression 34 essentially leading the movement. Three representative subsequent stages of movement are shown diagrammatically in FIG. 5 with the membrane 18 in each stage indicated as 18a, 18b and 18c respectively. As the gas 42 continues to be evolved and the membrane 18 extends or expands away from casing 8 and into the interior of casing 6 as indicated at 42a and 42b. This movement of the membrane 18 forces the liquid 22 out through the outlet port 28 and outlet tubing 52 as indicated at 22' and by arrow 54. The small amount of liquid which was in chamber 36 remains at the bottom of the device as the reactants continue reacting as indicated at 38". The conclusion of the dispensing of the liquid 22 from the unit 2 is illustrated in FIG. 6. At this point the reaction between the two reactants 38 and 40 is completed. The entire interior volume of the casing 4 is now filled with the evolved gas 42 and the membrane 18 has moved entirely to the opposite end of the casing 4 within half 6 as indicated at 18d. A small amount of remaining liquid may be contained in the tubing 52 as indicated at 22', and that can be drained or discarded as desired by the user. It will be seen that because of the generally spherical shape of the casing 4, the membrane in position 18d has forced essentially all of the liquid 22 from the casing 4 and that substantially none remains captured in pockets, crevices, corners or other traps. At this point the unit 2 can be disconnected from the tubing 52 and discarded. Assembly of the device 2 is straightforward. In the embodiment shown in FIGS. 3-6, the container 30 is first filled with the first reactant in liquid or dry form and then sealed. Container 30 is then placed in half 8 (preferably in well 32 if such is present). Thereafter, the second reactant 40 (as or in a liquid) is placed into the bottom of half 8 adjacent container 30 and membrane 18 is laid over the inside surface of half 8 to retain the liquid chemical reactant 40 within the chamber 36 which forms behind the membrane. The depression 34, if present, is normally formed in the membrane 18 either at the time of the membrane manufacture or at the time it is placed into the half 8. Thereafter half 6 is aligned with and placed over half 8, with the ends of the periphery of the membrane 18 compressed between the flanges 10 and 12, and the casing 4 is sterilized, closed, and sealed as indicated in FIGS. 3 or 7. However, it is possible that one could close, seal, and sterilize the device 2. The device 2 is now ready for filling with the medication or other liquid 22. [In the embodiments shown in FIGS. 13-17, the liquid reactant 40 is first placed in chamber under the dome and the sealing membrane is put into place to contain and isolate the reactant 40. The reactant 38, in either liquid or solid form, is then placed in container 30 (the remainder of well 32) and the device 4 with membrane 18 then assembled and filled with liquid 22 as described in the preceding paragraph.] Once liquid 22 has been placed into the interior 24 of casing 4, the device 2 can be closed by means of cap 62 placed over the outlet port 28, either used alone or in conjunction with one-way valve. This can be a simple closed cap which is force fitted or threaded onto neck 26 (if threads are present). A liquid seal such as an O-ring or gasket 64 may be present if desired. When it is time to use the device 2, cap 62 is removed and a female fitting 66 having an opening 68 in which tubing 52 is mounted is attached to neck 26 in place of cap 62. The device 2 is then ready for rupturing of the container 30 and dispensing of the liquid 22. In another embodiment, as shown in FIGS. 8A and 8B, cap 62 is replaced by a cap 70 formed of three pieces: a base 72, a rupturable membrane 74 and a outer annulus 76. The membrane 74 should be mounted under tension and made of a material with a significant degree of elasticity. The base 72 and the annulus 76 are sealed together at 78 to trap membrane 74 between the two. Both the annulus 76 and base 72 have a central hole 80 aligned with the outlet port 28. However, the membrane 74 is solid across the hole 80 and seals the device 2 against loss of liquid 22 or contamination from the environment. When it is desired to use the device 2, a piece of rigid tubing 52' is thrust into hole 80 to puncture membrane 74 and gain access to outlet port 28. If desired, the forward end of tubing 52 may be beveled as shown at 82 to form a cutting edge and facilitate puncturing of membrane 74. When punctured membrane 74, being elastic and under tension, will substantially retract out of the interior of neck 26, minimizing any tendency of the membrane material to interfere with the interference fit of tubing 52' in hole 80. The rigid portion of the tubing 52' can be just an end portion of the overall tubing 52 or it can be a separate coupling into which a flexible section of tubing 52' is added at the outward end (not shown). Other means of capping and sealing the unit will be immediately apparent to those skilled in the art. Also present may be exhaust or relief valve 45. This valve permits venting of the gas in the interior of the device should the pressure get too high for optimum flow of the dispensed liquid. It may also be used to vent the remaining gas 42 after the device has been emptied of liquid 22. A further control mechanism for dispensing a liquid 22 through the tubing 52 is shown in FIG. 9. The tubing 52 communicates with a patient intravenous apparatus or other dispersing apparatus through a coupler 84. The coupler 84 may be a male luer lock adapter that closes the line 52 when the coupler 84 is disconnected from the patient or other dispersing apparatus, if it is desired to retain some of the liquid for further and subsequent dispersing (in which case the membrane 18 will be held at some intermediate position such as 18a, 18b or 18c until the system is again connected to the patient or further dispensing apparatus and the fluid flows from the system). The luer lock valve may be supplemented by a well-known clamp 86 known as a Roberts clamp. In addition, the system may include a filter 88 and a further flow control valve or flow control orifice 90 such as a capillary tube. A highly preferred embodiment of the present invention is shown in FIGS. 18-20. For the purposes of this discussion, new reference numerals are assigned to like or similar parts described above. Referring first to FIG. 18, which is a cross-sectional side view of a preferred embodiment of the present invention taken along lines 18--18 of FIG. 17, where the device 100 is of a rectangular shape with rounded edges. It is separated into two separate compartments: the fluid delivery compartment 101 and the gas generation compartment 102. The fluid delivery compartment contains the liquid 103, that may contain a medication, that is to be delivered to a patient. Also within the fluid delivery compartment is the flexible membrane 104. The flexible membrane 104 is held in proximity to (or distended towards) the outer wall 105 in the lower section of the device 100 by the liquid 103. The flexible membrane 104 may contact the outer wall 105, or it may have a slight space 106 (as pictured). Preferably, the liquid 103 is additionally kept within the fluid delivery compartment 101, by a one-way valve 107, that generally has an outer body 108 with an encircled plunger 109. The plunger 109 typically has a proximal end 110 and a distal end 111 (in relation to the fluid delivery compartment 101). The proximal end 110 of the plunger 109 is typically larger than the distal end 111. Further, the outer body 108 of the valve 107 has a concentric ridge 112 so that the larger proximal end 110 of the plunger 109 abuts the ridge 112, preventing the liquid 103 from flowing through the valve 107. Additionally, the valve 107 can have biasing means, such a spring 113, that forces the proximal end 110 of the plunger 109 distally toward the ridge 112, thereby further aiding in preventing the liquid 103 from flowing through the valve 107. The valve 107 can be specially manufactured or can be a standard one-way luer fitting, such as those that are commercially available. For example, the Halkey-Roberts Corporation (St. Petersburg, Fla.) produces a variety of luer syringe check valves that can be used for this purpose. We prefer to use Halkey-Roberts Model No. V24200. It is preferred that all materials that are in contact with the liquid 103 in the fluid delivery compartment 101, such as the flexible membrane 104, the wall 114, and the valve 107 (and it components) be constructed of materials that are non-leaching and are appropriate for medical use. One example of such a material is ultrapure polypropylene and other similar materials. In U.S. Pat. No. 4,803,102 one formulation of ultrapure polypropylene is described. Thinner preparations of ultrapure polypropylene (i.e., 0.002 to 0.010 inch gauge) are used in preparing the flexible membrane 104 and thicker gauge materials (i.e., molded to 0.030 to 0.060 inch gauge) are preferred for making the casing (defined by walls 105 and 114). The gas generating compartment 102 is in fluid communication with the fluid delivery compartment 101 through a channel 115 and hole 122. Thus, when gas is generated in the gas generating compartment 102 it will travel through the channel 115 either filling or making the space 106 in the fluid delivery compartment 101. The gas generating compartment 102 additionally comprises a depressible member 116 which is sealingly joined to the case of the device 100. The depressible membrane sits above the gas generating compartment 102. Inside the gas generating compartment 102 are the reactants for generating the gas. Shown in this embodiment is a liquid reactant 117 that in a preferred embodiment is contained within a breakable sack 118. Above the sack rests, in this embodiment, a solid reactant pellet 119. In a highly preferred embodiment, the liquid reactant 117 is a solution of citric acid (7.5 gm/15 ml (2.6M)) and the solid reactant is a sodium carbonate "donut shaped" pellet, formed using a tablet or pill press of the shape shown in FIG. 2a. In the pellet, preferably 2.72 grams of sodium carbonate is mixed with 15% by weight of a filler, polyvinylpyrrolidone (PLASDONE, available from ISP Technologies, Inc., Wayne, N.J.) to make a 3.2 gm pellet. Moreover, preferably a room temperature vulcanizing (RTV) silicone adhesive was applied in strips, as shown in FIG. 2b, so as to reduce the surface area of the sodium carbonate and filler that would be exposed to the citric acid solution. In a preferred embodiment the RTV is PERMATEX®, available from Loctite Corporation, Cleveland, Ohio (Part No. 66B). Also, in this embodiment, the reactants are contained within a pouch 120. The pouch 120 in a highly preferred embodiment is composed of a hydrophobic material. Hydrophobic materials generally will contain liquids but will allow gases to pass, provided, some of their surface is not covered by a the liquid. Hydrophobic materials are typically formed from polymeric materials. Generally, they formed into a membrane. Examples of useful hydrophobic materials for preparing the pouch 120 are such materials as Tyvek® 1073B (Dupont), Versapel® 450 (Gelman), Goretex® 0.45μ polypropylene bucking, Celguard 2400 (Hoechst-Celanese), Porex® (a hydrophobic scintered polypropylene), and 3M BMF™ (Minnesota Mining and Manufacturing). As will be understood, the use of a hydrophobic pouch 120 is very useful in that it contains the reactants within the gas generating chamber 102. This fact reduces concerns that the reactants could mix with the liquid in the fluid delivery compartment 101. However, it is critical to note that, as mentioned, the hydrophobic pouch 120 will release gas only so long as a gas pocket 121 exists. Therefore, the hydrophobic pouch must be carefully designed to ensure that the gas pocket 121 is maintained throughout the course of the reaction. If the gas pocket 121 were not present, the pouch 120 would burst and the contents (particularly the liquid reactant 117) of the gas generating compartment 102 would spill into the fluid delivery compartment 101 through the channel 115 and the hole 122. Since the liquid reactant 117 would no longer be in substantial contact with the solid reactant 119, the reaction would essentially terminate and limited additional gas would be evolved. However, as will be appreciated, because of the generation of gas through the reaction, there will be a tendency for the pouch 120 to reinflate and sparge gas, prior to failure. An additional advantage to the use of the hydrophobic pouch is the fact that it enables the device 100 to be used in any orientation. The reactants in the gas generating chamber 102 are physically separated from the fluid delivery compartment 101 and the liquid 103, and no matter what orientation the device is moved to (so long as the gas pocket 121 exists) gas will continue to be delivered to the fluid delivery compartment 101. This makes the device 100 very versatile. For example, medical personnel do not have to carefully orient the device 100 and ambulatory patients can carry the device in their pockets. It will be appreciated that the advantage associated with the hydrophobic pouch (i.e., allowing the orientation of the pump to be an insubstantial consideration since the chemical reactants will not get near the fluid to be delivered to the patient and allowing the chemical reactants to stay in contact with one another so as to continue the chemical reaction therebetween) can be achieved through a number of other mechanisms. In general, therefore, any mechanism that allows the gas generated by the reaction between the reactants to be communicated to the pump while the chemical reactants remain in contact away from the pump can be used. Non-limiting examples of such mechanisms include, in addition to the hydrophobic pouch mentioned above, placing the reactants in a float or on rollers in a container so that the reactants remain in the container despite the orientation; use of a hydrophobic membrane in a lumen in communication with a reactant chamber and a pump chamber; lining a container, otherwise sealed, with a hydrophobic material extending above any liquid level and providing a lumen from the container, behind the hydrophobic material, to communicate with the pump. However, returning the embodiment shown in FIG. 19, in order to operate the pump in this embodiment, a user can simply depress the depressible membrane 116 down into the gas generating compartment 102 with their index finger, for example. This action will force the hydrophobic pouch 120 down onto the solid reactant 119. Such action will break the sack 118 that contained the liquid reactant 117. The chemicals will react and gas will be generated. Provided, as mentioned above, that the gas pocket 121 is maintained, gas will flow through the hydrophobic pouch 120 and be communicated through the hole 122 into the channel 115 and into the fluid delivery compartment 101. Thereafter, provided that the valve 107 is opened through manually depressing the distal end 111, proximally, liquid 103 will begin to flow through the valve 107. As gas continues to be generated the flexible membrane 104 will be displaced away from wall 105 increasing the size of the space 106 between the wall 105 and the flexible membrane 104 as the liquid 103 is delivered out of the device 100. As an additional control feature and for safety, a preferred embodiment of the present invention further includes a pressure relief valve. A simple, but highly effective, pressure relief valve is shown in FIG. 20. The pressure relief valve is in communication with the gas generating chamber through a gas channel 123. The gas channel extends through the casing 125 of the device into a stem 124 that is topped by a mandrel 126. The mandrel 126 is topped by an elastomeric material 127 that concentrically and sealingly surrounds the mandrel 126. The elastomeric material is essentially similar to a silicone rubber septum that folds over, surrounds, and seals around the mandrel 126. While the system operates at preferably 10 psi or less, the elastomeric material 127 will not allow gas to escape. However, when the system exceeds 10 psi, the gas will force out the sides of the elastomeric material 127 allowing gas to escape. We have discovered that use of the pressure relief valve in combination with the citric acid/sodium carbonate, Plasdone, RTV pellets, as described above, we can achieve an almost completely linear pressure profile as is shown in FIG. 21. Such a linear pressure profile gives rise to an almost perfectly linear flow rate of fluid from the pump. It will now also be appreciated that a variety of additional features could be added to the pressure relief valve of the present invention in order to lend greater control and conserve gas pressure. For example, the pressure relief valve shown in FIG. 20 could be replaced by a balloon or other pressure/gas reserve mechanism. There are, for instance, inelastic balloon structures that do not show enhanced pressure at reduced diameters. Such materials could be attached to the mandrel 126 in FIG. 20 to capture excess gas. As well, simple two way regulators can be readily conceived of by those of ordinary skill in the art to remove excess gas at a given pressure from the system and introduce gas back to the system when the pressure falls below a certain, predetermined pressure. It will be evident from the above that there are many additional embodiments of this invention which, while not expressly described above, are clearly within the scope and spirit of the invention. The above description is therefore intended to be exemplary only and the invention is to be limited solely by the appended claims.

A liquid dispensing device and the method of dispensing liquid are disclosed. The device is uniquely suited to meet the requirements of hospitals and other institutions for long shelf life in inert condition and ready activation when needed. The device includes a hollow gas- and liquid-tight casing (preferably spherical or cylindrical), a flexible gas- and liquid-tight membrane disposed entirely across the casing interior dividing the interior into a propellant chamber and a liquid chamber; an outlet port from the liquid chamber; two mutually reactive chemicals in the propellant chamber but separated by a barrier; and a member to breach the barrier and permit the chemicals to come into contact; the two chemicals being reactive upon contact to form a propellant gas. The propellant gas thereupon expands against the membrane, moves the membrane to enlarge the propellant chamber, decrease the liquid chamber, and expel the contained liquid from the liquid chamber through the outlet port. The barrier may be breached in any convenient manner, as by breaking a frangible barrier or perforating a perforable one. Preferably at least one of the chemicals is in liquid form, and one is a Group I or II metal carbonate or bicarbonate while the other is an acid, acid anhydride or acid salt; the most preferred combination is sodium carbonate and citric acid.

This application claims benefit of Japanese Patent Application No. 2007-185500 filed in Japan on Jul. 17, 2007, the contents of which are incorporated by this reference. BACKGROUND OF THE INVENTION The present invention relates to solid-state imaging apparatus having photoelectric conversion device, and more particularly relates to the solid state imaging apparatus where all pixel signals are read out at high rate with setting a certain exposure time so that image having high S/N can be acquired. It is known to construct solid-state imaging apparatus such that photoelectric conversion sections of all pixels are concurrently reset to start accumulation of signal, and after concurrently transferring signals of the photoelectric conversion sections of all pixels to memory after a predetermined time, the signals are sequentially read out. In such a solid-state imaging apparatus, retaining time of signal at memory is different from one pixel row to another. For this reason, leak current occurring at memory and electric charge occurring due to leakage of light shed on memory are different between each pixel row depending on such retaining period, and thus become cause of shading. To mitigate this, Japanese Patent Application Laid-Open Publication 2006-10889 for example has proposed a solid-state imaging apparatus where elimination of shading is made possible by subtraction between the pixel signals of a first row or column and the pixel signals of a second row or column. FIG. 1 is a diagram showing construction of the solid-state imaging apparatus disclosed in the publication, and FIG. 2 is a timing chart for explaining its operation. The construction of the solid-state imaging apparatus disclosed in the above publication will now be described by way of FIG. 1 . Provided at the inside of pixel PIX 11 are: a photoelectric conversion section PD 11 ; a memory C 11 (hereinafter referred simply to as FD) for accumulating signal generated at the photoelectric conversion section PD 11 ; a transfer switch MT 11 for controlling transfer from the photoelectric conversion section PD 11 to FD; a reset switch MR 11 for resetting FD; an amplification section MA 11 for amplifying signal of FD; and a select switch MS 11 for selecting the pixel. These are connected as shown in FIG. 1 to form a pixel. A plurality of pixels having such construction are two-dimensionally arranged (2 rows by 2 columns in the illustrated example) to form a pixel section. It should be noted that the constituent components of the other pixels PIX 12 , PIX 21 , PIX 22 of the pixel section are denoted by those numerals that correspond to row and column of each pixel. The transfer switches MT 11 , MT 12 of pixels PIX 11 , PIX 12 of the first row are controlled by transfer control signal φTX 1 outputted from a vertical scanning circuit 101 , and transfer switches MT 21 , MT 22 of pixels PIX 21 , PIX 22 of the second row are controlled by transfer control signal φTX 2 . The select switches MS 11 , MS 12 of pixels PIX 11 , PIX 12 of the first row are controlled by select control signal φSEL 1 , and the select switches MS 21 , MS 22 of pixels PIX 21 , PIX 22 of the second row are controlled by select control signal q SEL 2 . The pixel output signals of selected row are written to a line memory 102 through a vertical signal line 105 . Subsequently, the output signals stored at the line memory 102 are read out by a horizontal scanning circuit 103 . It should be noted that numeral 104 in FIG. 1 denotes a control section for controlling operation of the vertical scanning circuit 101 and line memory 102 . The operation of the solid-state imaging apparatus having such construction will now be described by way of a timing chart shown in FIG. 2 . At first, transfer control signals φTX 1 , φTX 2 , and reset control signals φRST 1 , φRST 2 are driven to high level to start concurrent reset of photoelectric conversion section PD and FD of all pixels. Next, transfer control signals φTX 1 , φTX 2 are brought to low level to end reset period of the photoelectric conversion section PD so that accumulation of light signal is started. Next, reset control signals φRST 1 , φRST 2 are brought to low level to end reset of FD. Subsequently, transfer control signal φTX 1 to the pixels of the first row is driven to high level to end an accumulation period and effect transfer to FD of the accumulated electric charge of photoelectric conversion section PD of the pixels of the first row. The transfer control signal φTX 2 to the pixels of the second row on the other hand maintains low level so as not to effect transfer to FD of the accumulated electric charge of photoelectric conversion section PD of the pixels of the second row. Next, pixel rows selected by select control signal in the manner of time series are sequentially read out. In particular at first, the select control signal φSEL 1 is driven to high level to output pixel signals of the pixel (main pixel) row of the first row to the line memory 102 through the vertical signal line 105 , and the select control signal φSEL 1 is brought to low level to end the outputting. Next, select control signal φSEL 2 is driven to high level to output pixel signals of the pixel (sub pixel) row of the second row to the line memory 102 . These operations are sequentially continued. The output signal of such main pixel row (first pixel row) becomes a signal where FD leak signal (referred to as Vsf in this description) and signal due to leakage light (referred to as Vse in this description), i.e. noise signals are added to light signal (referred to as Vp in this description) accumulated at the photoelectric conversion section. The output signal of the main pixel row supposed as Vs 1 is represented in symbols as in the following equation (1). Vs 1= Vp+Vsf+Vse   (1) Further, the output signal of sub pixel row (second pixel row) becomes a signal where FD leak signal Vnf and signal by leakage light Vne, i.e. noise signals are added up so that the output signal of the sub pixel row supposed as Vn 1 is represented in symbols as in the following equation (2). Vn 1 =Vnf+Vne   (2) In this case, since the main pixel and the sub pixel are read out at substantially the same point in time, FD leak signal and signal due to leakage light are respectively of substantially the same value, and are represented in symbols as: Vsf=Vnf, Vse=Vne. Accordingly, difference between the main pixel signal and the sub pixel signal is obtained as: Vs 1 −Vn 1 =Vp Further, the disposition of main pixel 1 and sub pixel 2 in the pixel section may be as shown in FIG. 3 so that the main pixel 1 and sub pixel 2 are disposed at every other row. SUMMARY OF THE INVENTION In a first aspect of the invention, there is provided a solid-state imaging apparatus including: a pixel section with a plurality of pixels that are two-dimensionally arranged, the pixels including a first pixel having a first input section for accumulating a signal associated with object image, a first amplification section for amplifying signals accumulated at the first input section so as to generate a first pixel signal, a first reset section for resetting the first input section, and a first select section for selecting the first amplification section to cause the first pixel signal to be outputted onto a signal output line, and a second pixel having a second input section for accumulating a signal corresponding to a noise generated at the first input section, a second amplification section for amplifying signals accumulated at the second input section so as to generate a second pixel signal, a second reset section for resetting the second input section, and a second select section for selecting the second amplification section to cause the second pixel signal to be outputted onto the signal output line; a control section for, after simultaneously and concurrently resetting all the first and second input sections, effecting control so as to cause all the first input sections to concurrently and simultaneously accumulate the signal associated with the object image having the same exposure start timing; a correction data retaining section for retaining correction data to correct a characteristic variance between the first input section and the second input section; and a variance correction section for generating a third pixel signal corresponding to a difference between the first pixel signal and the second pixel signal where the characteristic variance is corrected based on the correction data. In a second aspect of the invention, the first pixel in the solid-state imaging apparatus according to the first aspect further includes a first photoelectric conversion section and a first transfer section for transferring a signal generated at the first photoelectric conversion section to the first input section, and the second pixel further includes a second photoelectric conversion section and a second transfer section for transferring a signal generated at the second photoelectric conversion section to the second input section, the control section effecting control so as to start an accumulation of the signal at the first and second photoelectric conversion sections with simultaneously and concurrently resetting all the first and second photoelectric conversion sections, and after a predetermined time so as to simultaneously and concurrently effect a transfer of the signal from the first photoelectric conversion section to the first input section for the first pixels while on the other hand so as not to effect a transfer from the second photoelectric conversion section to the second input section for the second pixels. In a third aspect of the invention, the first pixel in the solid-state imaging apparatus according to the first aspect further includes a photoelectric conversion section and a first transfer section for transferring a signal generated at the photoelectric conversion section to the first input section, and the second pixel further includes a connecting section for connecting between a constant potential supply and the second input section, the control section effecting control so as to start an accumulation of the signal at the photoelectric conversion section with simultaneously and concurrently resetting the photoelectric conversion section of all the first pixels, and after a predetermined time so as to simultaneously and concurrently effect a transfer of the signal from the photoelectric conversion section to the first input section for the first pixels while on the other hand so as not to effect a function of the connecting section for the second pixels. In a fourth aspect of the invention, the second pixel in the solid-state imaging apparatus according to the first aspect is disposed for every predetermined ones of the first pixels. In a fifth aspect of the invention, the variance correction section in the solid-state imaging apparatus according to the first aspect corrects the correction data in accordance with an exposure time. In a sixth aspect of the invention, the correction data retaining section in the solid-state imaging apparatus according to the first aspect, after simultaneously resetting the first and second input sections, generates the correction data based on an output signal from the first pixel obtained with accumulating at the first input section the signal associated with the object image having the same exposure start timing and substantially zero exposure time and an output signal from the second pixel. In a seventh aspect of the invention, the correction data retaining section in the solid-state imaging apparatus according to the first aspect, after simultaneously resetting the first and second input sections, generates the correction data based on an output signal from the first pixel obtained without accumulation of the signal associated with the object image at the first input section and an output signal from the second pixel. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a circuit diagram partially in blocks showing an example of construction of prior-art solid-state imaging apparatus. FIG. 2 is a timing chart for explaining operation of the solid-state imaging apparatus according to the prior-art example shown in FIG. 1 . FIG. 3 shows an example of disposition of main pixels and sub pixels in a pixel section in the solid-state imaging apparatus according to the prior-art example shown in FIG. 1 . FIGS. 4A and 4B are to show construction of an embodiment of the solid-state imaging apparatus according to the invention, and to explain computing operation of image data thereof. FIG. 5 is a timing chart for explaining drive operation at the time of acquiring correction image data in the first embodiment shown in FIG. 4A . FIG. 6 is a timing chart for explaining drive operation at the time of acquiring correction image data in the solid-state imaging apparatus according to a second embodiment of the invention. FIG. 7 shows construction of a modification of the solid-state imaging apparatus according to the second embodiment. FIG. 8 is a timing chart for explaining drive operation at the time of acquiring correction image data in the solid-state imaging apparatus according to a third embodiment of the invention. FIGS. 9A and 9B are an illustration for showing outline of computing operation of image data in the solid-state imaging apparatus according to a fourth embodiment of the invention, and a timing chart for explaining operation for acquiring differential image data thereof. FIG. 10 shows construction of solid-state imaging apparatus according to a fifth embodiment of the invention. FIG. 11 shows construction of solid-state imaging apparatus according to a sixth embodiment of the invention. FIG. 12 shows construction of solid-state imaging apparatus according to a seventh embodiment of the invention. FIG. 13 is a timing chart for explaining operation of the solid-state imaging apparatus according to the seventh embodiment shown in FIG. 12 . FIG. 14 shows construction of solid-state imaging apparatus according to an eighth embodiment of the invention. FIG. 15 shows construction of a modification of the solid-state imaging apparatus according to the eighth embodiment shown in FIG. 14 . FIG. 16 shows construction of another modification of the solid-state imaging apparatus according to the eighth embodiment shown in FIG. 14 . FIG. 17 shows construction of solid-state imaging apparatus according to a ninth embodiment of the invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of the solid-state imaging apparatus according to the invention will be described below with reference to the drawings. Embodiment 1 A first embodiment will now be described. FIG. 4A shows construction of the solid-state imaging apparatus according to the first embodiment. A correction data generation section 111 , correction data retaining section 112 , and FD variance correction section 113 are added in as compared to the prior-art example shown in FIG. 1 . The construction other than these added components is the same as the prior-art example shown in FIG. 1 and will not be described. Further FIG. 4B schematically explains an image data computing method. An outline of the computing method of image data will now be described by way of FIG. 4B . At first similarly to the prior-art example, output signal of sub pixel consisting of FD noise signal containing variance is differentiated from output signal of main pixel containing light signal and FD noise signal to acquire a differential image data. Next at the correction data generation section 111 , a difference between FD noise signal of the main pixel and FD noise signal of the sub pixel containing variance is taken to obtain a correction image data, which is retained at the correction data retaining section 112 . Next an image having excellent S/N can be obtained such that the correction image data is subtracted from the differential image data at the FD variance correction section 113 to compute final image data. The disposition of main pixels and sub pixels in the pixel section is similar to the prior-art example shown in FIG. 3 and will not be described. Further the operation for acquiring the differential image data is the same as the operation for acquiring a differential image data in the prior-art solid-state imaging apparatus shown in the timing chart of FIG. 2 , and will not be described. The drive method at the time of acquiring correction image data will now be described by way of a timing chart of FIG. 5 . At first, transfer control signals φTX 1 , φTX 2 , and reset control signals φRST 1 , φRST 2 are driven to high level to start concurrent reset of the photoelectric conversion section PD and FD (memory) of all pixels. Next, the transfer control signals φTX 1 , φTX 2 are brought to low level to end a reset period of the photoelectric conversion section PD, and an accumulation of light signal is started. Next, the reset control signals φRST 1 , RST 2 are brought to low level to end the reset of FD, and to start accumulation of signal due to leak at FD and a leakage light. After effecting the accumulation at FD for the same time duration as the acquiring of differential image data, rows selected by select control signal in a manner of time series are sequentially read out while the transfer control signals φTX 1 , φTX 2 are kept to low level. In particular at first, select control signal φSEL 1 is driven to high level to output pixel signals of the pixel (main pixel) row of the first row to the line memory 102 through the vertical signal line 105 , and the select control signal φSEL 1 is then brought to low level to end the outputting of pixel signals of the first row. Subsequently, select control signal φSEL 2 is driven to high level to output pixel signals of the pixel (sub pixel) row of the second row to the line memory 102 through the vertical signal line 105 , and the select control signal φSEL 2 is then brought to low level to end the outputting of pixel signals of the second row. In such drive operation, output signal of the main pixel (pixels of the first row) is a signal where FD leak signal (referred to as Vsf in this description) and signal due to leakage light (referred to as Vse in this description), i.e. noise signals are added up. Supposing the output signal of the main pixel as Vs 3 , it is represented in symbols as in the following equation (3). Vs 3 =Vsf+Vse   (3) Further, output signal of the sub pixel (pixels of the second row) is a signal where FD variance signal Vnb is added to FD leak signal Vnf and leakage light signal Vne, i.e. noise signals so that the output signal of the sub pixel supposed as Vn 3 is represented in symbols as in the following equation (4). Vn 3= Vnf+Vne+Vnb   (4) In this case, the point in time at which the output signals of the main pixel and the sub pixel are read out is substantially the same, and accumulation period of FD is substantially equal so that the FD leak signals and the leakage light signals are respectively of substantially the same value and are represented by equation of symbols as: Vsf=Vnf, Vse=Vne. Accordingly, a correction image data Vr obtained by difference between the output signals of the main pixel and the sub pixel at the correction data generation section 111 is represented in symbols as in the following equation (5). Vr=Vs 3− Vn 3= Vnb   (5) Here, since the differential image data is (Vp−Vnb), it is possible to acquire the light signal Vp alone and obtain image having excellent S/N by taking difference between the differential image data and the correction image data at the FD variance correction section 113 . Embodiment 2 A second embodiment will now be described. The construction itself of the solid-state imaging apparatus according to the second embodiment is the same as the construction of the solid-state imaging apparatus according to the first embodiment shown in FIG. 4A , and its description by way of drawing will be omitted. The second embodiment is different from the first embodiment in the method of acquiring correction image data. FIG. 6 is a timing chart for explaining drive operation at the time of acquiring correction image data in the solid-state imaging apparatus according to the second embodiment. It is different in accumulation time from the timing chart of the first embodiment shown in FIG. 5 . In particular at first, transfer control signals φTX 1 , φTX 2 , and reset control signals φRST 1 , φRST 2 are driven to high level to start concurrent reset of the photoelectric conversion section PD and FD of all pixels. Subsequently, the transfer control signals φTX 1 , φTX 2 are brought to low level to end the reset period of the photoelectric conversion section PD, and at the same time the reset control signals φRST 1 , φRST 2 are brought to low level to end the reset of FD. Subsequently in the condition of zero accumulation time of the photoelectric conversion section PD and FD, rows selected by select control signal in a manner of time series are sequentially read out while the transfer control signals φTX 1 , φTX 2 are kept to low level. In particular immediately after bringing the transfer control signals φTX 1 , φTX 2 , and reset control signals φRST 1 , φRST 2 to low level, select control signal φSEL 1 at first is driven to high level to output the output signal of the pixel (main pixel) row of the first row to the line memory 102 , and the select control signal φSEL 1 is then brought to low level to end the outputting of pixel signals of the first row. Next, select control signal φSEL 2 is driven to high level to output the output signal of the pixel (sub pixel) row of the second row to the line memory 102 , and the select control signal φSEL 2 is then brought to low level to end the outputting of pixel signals of the second row. In such drive operation, output signal of the main pixel (pixels of the first row) is the signal where FD leak signal (referred to as Vsf in this description) and signal due to leakage light (referred to as Vse in this description), i.e. noise signals are added up. Supposing the output signal of the main pixel as Vs 4 , it is represented in symbols as in the following equation (6). Vs 4= Vsf+Vse   (6) Further, output signal of the sub pixel is the signal where FD variance signal Vnb is added to FD leak signal Vnf and leakage light signal Vne, i.e. noise signals so that the output signal of the sub pixel supposed as Vn 4 is represented in symbols as in the following equation (7). Vn 4 =Vnf+Vne+Vnb   (7) In this case, since the point in time at which the output signals of the main pixel and the sub pixel are read out is substantially the same, the FD leak signals and the leakage light signals are respectively of substantially the same value and are represented by equation of symbols as: Vsf=Vnf, Vse=Vne. Accordingly, correction image data Vr obtained by difference between the output signals of the main pixel and the sub pixel is represented in symbols as in the following equation (8). Vr=Vs 4 −Vn 4 =Vnb   (8) Here, since the differential image data is (Vp−Vnb), it is possible to acquire the light signal Vp alone and obtain image having excellent S/N by taking difference between the differential image data and the correction image data Vr. Further, by setting zero the accumulation time of the photoelectric conversion section PD and FD, the time for acquiring correction image data can be shortened. The data computing method after correction is the same as in the first embodiment and will not be described. Further, it is also possible to dispose the main pixel and sub pixel alternately on every other column as shown in FIG. 7 . Embodiment 3 A third embodiment will now be described. The construction itself of the solid-state imaging apparatus according to the third embodiment is the same as the construction of the solid-state imaging apparatus according to the first embodiment shown in FIG. 4A , and its description by way of drawing will be omitted. The third embodiment is different from the first embodiment in the method of acquiring correction image data. FIG. 8 is a timing chart for explaining drive operation at the time of acquiring correction image data in the solid-state imaging apparatus according to the fourth embodiment. While in the timing chart of the second embodiment shown in FIG. 6 , the read is effected with keeping the transfer control signal φTX 1 of the main pixel to low level when pixel signals are read out of the first row by driving select control signal φSEL 1 to high level, the third embodiment is different from the second embodiment in that the transfer control signal φTX 1 of the main pixel is driven to high level. In particular at first, transfer control signals φTX 1 , φTX 2 , and reset control signals φRST 1 , φRST 2 are driven to high level to start concurrent reset of the photoelectric conversion section PD and FD of all pixels. The transfer control signals φTX 1 , φTX 2 are then brought to low level to end the reset period of the photoelectric conversion section PD. Further at the same time, the reset control signals φRST 1 , φRST 2 are brought to low level to end the reset of FD. Immediately after that, the transfer control signal φTX 1 of the main pixel row is driven to high level to effect transfer to FD of signal of the photoelectric conversion section PD. Next, rows selected by select control signal in a manner of time series are sequentially read out. In particular at first, select control signal φSEL 1 is driven to high level to output the light signal of the pixel (main pixel) row of the first row to the line memory 102 , and the select control signal φSEL 1 is then brought to low level to end the outputting of pixel signals of the first row. Next, select control signal φSEL 2 is driven to high level with keeping to low level the transfer control signal φTX 2 to the second pixel row to output the output signal of the pixel (sub pixel) row of the second row to the line memory 102 , and the select control signal φSEL 2 is then brought to low level to end the outputting of pixel signals of the second row. In such drive operation, output signal of the main pixel (pixels of the first row) is the signal where FD leak signal (referred to as Vsf in this description) and signal due to leakage light (referred to as Vse in this description), i.e. noise signals are added to light signal Vpd′ accumulated at the photoelectric conversion section PD. Supposing the signal of the main pixel as Vs 5 , it is represented in symbols as in the following equation (9). Vs 5= Vpd′+Vsf+Vse   (9) Further, output signal of the sub pixel (pixels of the second row) is the signal where FD variance signal Vnb is added to FD leak signal Vnf and leakage light signal Vn 1 , i.e. noise signals so that the output signal of the sub pixel supposed as Vn 5 is represented in symbols as in the following equation (10). Vn 5= Vnf+Vne+Vnb   (10) In this case, since the time and period of reading output signals of the main pixel and the sub pixel are substantially the same, the FD leak signals and the leakage light signals are respectively of substantially the same value and are represented by equation of symbols as: Vsf=Vnf, Vse=Vne. At the same time, since light signal is not accumulated when transfer control signal φTX 1 is driven to high level immediately after reset of the photoelectric conversion section PD to make very short the accumulation time of the photoelectric conversion section PD, Vpd′≈0 is obtained. Accordingly, correction image data Vr obtained by difference between the output signals of the main pixel and the sub pixel is represented in symbols as in the following equation (11). Vr=Vs 5 −Vn 5 =Vnb   (11) Here, since the differential image data is (Vp−Vnb), it is possible to acquire the light signal Vp alone and obtain image having excellent S/N by taking difference between the differential image data and the correction image data Vr. Further in addition to the capability of reducing time of acquiring correction image data similarly to the second embodiment, noise can be effectively removed, since the only difference is accumulation time and the drive pulses for the main pixel and for the sub pixel are the same between when acquiring correction image data and when acquiring differential image data. The data computing method after correction is the same as in the first embodiment and will not be described. Embodiment 4 A fourth embodiment will now be described. The construction of the solid-state imaging apparatus itself according to the fourth embodiment is the same as the solid-state imaging apparatus according to the first embodiment shown in FIG. 4A , and its description by way of drawing will be omitted. The fourth embodiment is different from the first embodiment in that an exposure time correction factor is used to correct differential image data in computing image data. An outline of the computing method of image data in the fourth embodiment will now be described by way of FIG. 9A . At first, a differential image data is acquired by subtracting output signal of the sub pixel containing FD noise from output signal of the main pixel that contains light signal and FD noise. Next, variance data (corrected correction image data) of the main pixel's FD noise and the sub pixel's FD noise corrected by correction factor computed for example from exposure time is removed from the differential image data to compute image data. The operation of acquiring the differential image data according to the fourth embodiment will now be described by way of a timing chart shown in FIG. 9B . At first, transfer control signals φTX 1 , φTX 2 , and reset control signals φRST 1 , φRST 2 are driven to high level to start concurrent reset of the photoelectric conversion section PD and FD of all pixels. Next, the transfer control signals φTX 1 , φTX 2 , and reset control signals φRST 1 , φRST 2 are brought to low level to end the reset of the photoelectric conversion section PD and reset of FD, and accumulation of the photoelectric conversion section PD is started. Subsequently, the transfer control signal φTX 1 is driven to high level to end the accumulation period and effect a transfer to FD of accumulated electric charge of the photoelectric conversion section PD of the pixel (main pixels) of the first row. The transfer control signal φTX 2 on the other hand maintains low level so that a transfer to FD of accumulated electric charge of the photoelectric conversion section PD of the pixel (sub pixels) of the second row is not effected. Next, rows selected by select control signal in a manner of time series are sequentially read out. In particular at first, select control signal φSEL 1 is driven to high level to output the light signal of the pixel (main pixel) row of the first row to the line memory 102 , and the select control signal φSEL 1 is then brought to low level to end the outputting of pixel signals of the first row. Next, select control signal φSEL 2 is driven to high level to output signal of the pixel (sub pixel) row of the second row to the line memory 102 , and the select control signal φSEL 2 is then brought to low level to end the outputting of pixel signals of the second row. The output signal of the main pixel row by such drive operation is the signal where FD leak signal (referred to as Vsf in this description) and signal due to leakage light (referred to as Vse in this description), i.e. noise signals are added to light signal (referred to as Vp in this description) accumulated at the photoelectric conversion section PD. Supposing the signal of the main pixel as Vs 6 , it is represented in symbols as in the following equation (12). Vs 6= Vp+Vsf+Vse   (12) Further, output signal of the sub pixel row is the signal where FD variance signal (referred to as Vnb 2 in this description) is added to FD leak signal Vnf and leakage light signal Vne, i.e. noise signals. The output signal of the sub pixel supposed as Vn 6 is represented in symbols as in the following equation (13). Vn 6= Vnf+Vne+Vnb 2  (13) Here, FD variance signal Vnb 2 is continuously generated during the period from the end of reset of FD to the time at which it is read out. It should be noted that, in the example of operation shown in the timing chart of FIG. 9B , period during which variance signal Vnb 2 is being generated is the period where read waiting time (t′) is added to accumulation time (T). Such FD variance signal Vnb 2 is represented in symbols as in the following equation (14). Vnb 2= Nb ×( T+t ′)  (14) where Nb is FD variance signal generated per unit time. By substituting the above equation (14) for equation (13) of the output signal Vn 6 of the sub pixel row, the following equation (15) is obtained. Vn 6= Vnf+Vne+Nb ×( T+t ′)  (15) It should be noted in this case that, since the main pixel and the sub pixel are read out at and in substantially the same time and period, the FD leak signals and the leakage light signals are respectively of substantially the same value and are represented by equation of symbols as: Vsf=Vnf, Vse=Vne. Accordingly, when differential image data is computed by taking difference between the main pixel signal and the sub pixel signal, the following equation (16) is obtained. Vs 6− Vn 6= Vp−Nb ×( T+t ′)  (16) Although the method of acquiring correction image data in this case is the same as the first embodiment or the second embodiment and will not be described, the correction image data is obtained as −Vnb. It is to be noted that the correction image data (−Vnb) here is the product by multiplication of FD variance signal Nb occurring per unit time and the read waiting time t′ and is represented in symbols as: Vnb=Nb×t′ Accordingly, it is possible to acquire the light signal Vp alone and obtain image having excellent S/N such that correction image data is multiplied by factor computed from accumulation time, i.e. exposure time correction factor (T+t′)/t′ to correct the correction image data, and the corrected correction image data is removed from the differential image data. Embodiment 5 A fifth embodiment will now be described. FIG. 10 shows construction of the solid-state imaging apparatus according to the fifth embodiment. Included at the inside of a main pixel PIX 11 in the solid-state imaging apparatus according to the fifth embodiment are: a photoelectric conversion section PD 11 ; FD (memory C 11 ) for accumulating signal generated at the photoelectric conversion section PD 11 ; a transfer switch MT 11 for controlling a transfer from the photoelectric conversion section PD 11 to FD; a reset switch MR 11 for resetting FD; an amplification section MA 11 for amplifying signal of FD; and a select switch MS 11 for selecting the pixel. Further, included at the inside of a sub pixel PIX 21 are: a switch MT 21 connected at one end to a constant potential supply having the same construction as the transfer switch MT 11 of the main pixel PIX 11 ; FD (memory C 21 ) for accumulating a noise; a reset switch MR 21 for resetting FD; an amplification section MA 11 for amplifying signal of FD; and a select switch MS 21 for selecting the pixel. The constituent components of each pixel are connected as shown in FIG. 10 , and main pixels and sub pixels are two-dimensionally arranged (2 rows by 2 columns in the illustrated example) on every other row to form a pixel section. It should be noted that the constituent components of the other main pixel PIX 12 , and sub pixel PIX 22 of the pixel section are denoted by those numerals that correspond to row and column of each pixel. The transfer switches MT 11 , MT 12 of the main pixels PIX 11 , PIX 12 of the first row are controlled by transfer control signal φTX 1 outputted from a vertical scanning circuit 101 , and switches MT 21 , MT 22 of the sub pixels PIX 21 , PIX 22 of the second row are controlled by control signal φTX 2 . The select switches MS 11 , MS 12 of the main pixels of the first row are controlled by select control signal φSEL 1 , and the select switches MS 21 , MS 22 of the sub pixels of the second row by select control signal φSEL 2 ; the output signals of selected pixel row are written to a line memory 102 . Subsequently, the output signals stored at the line memory 102 are read out by a horizontal scanning circuit 103 . Further included in the same manner as the first embodiment shown in FIG. 4A are: a correction data generation section 111 ; correction data retaining section 112 ; and FD variance correction section 113 . The operation of acquiring a differential image data, operation of acquiring a correction image data, and computing operation of a final image data after correction in the solid-state imaging apparatus according to this embodiment are all the same as those in the first to fourth embodiments and will not be described. In the present embodiment, image having excellent S/N can be obtained by using the pixel construction as described above, since an area of the sub pixel without having photoelectric conversion section PD can be made smaller, and on the other hand since a larger area can be provided for the photoelectric conversion section PD of the main pixel. Embodiment 6 A sixth embodiment will now be described. FIG. 11 shows construction of the solid-state imaging apparatus according to the sixth embodiment. The sixth embodiment is different from the first embodiment shown in FIG. 4A only in construction of connection of a portion inside the pixel, and the construction of the rest is the same as the first embodiment. In particular, included at the inside of a main pixel PIX 11 are: a photoelectric conversion section PD 11 ; FD (memory C 11 ) for accumulating signal generated at the photoelectric conversion section PD 11 ; a transfer switch MT 11 for controlling a transfer from the photoelectric conversion section PD 11 to FD; a reset switch MR 11 for resetting FD; an amplification section MA 11 for amplifying signal of FD; and a select switch MS 11 for selecting the pixel. Further included at the inside of a sub pixel PIX 21 are: a photoelectric conversion section PD 21 ; FD (memory C 21 ) for accumulating signal generated at the photoelectric conversion section PD 21 ; a transfer switch MT 21 for controlling transfer from the photoelectric conversion section PD 21 to FD; a reset switch MR 21 for resetting FD; an amplification section MA 21 for amplifying signal of FD; and a select switch MS 21 for selecting the pixel. It is similar to the first embodiment in that the main pixels and the sub pixels are two-dimensionally arranged (2 rows by 2 columns in the illustrated example) on every other row. It is different from the first embodiment in that, while the amplification section of each pixel in the first embodiment is directly connected to line memory 102 , the select switch of each pixel is connected to line memory 102 in the sixth embodiment. The transfer switches MT 11 , MT 12 of the main pixels of the first row are controlled by transfer control signal φTX 1 , and transfer switches MT 21 , MT 22 of the sub pixels of the second row by transfer control signal φTX 2 ; and the select switches MS 11 , MS 12 of the main pixels of the first row are controlled by select control signal φSEL 1 , and the select switches MS 21 , MS 22 of the sub pixels of the second row by select control signal φSEL 2 . Further it is the same as the first embodiment in the operation where the output signals of selected pixel row are written to the line memory 102 , and the output signals stored at the line memory 102 are subsequently read out by horizontal scanning circuit 103 . The operation of acquiring a differential image data, operation of acquiring a correction image data, and computing operation of a final image data after correction in the solid-state imaging apparatus according to the sixth embodiment are the same as those in the first to fourth embodiments and will not be described. Also in the sixth embodiment, image having excellent S/N can be similarly obtained. Embodiment 7 A seventh embodiment will now be described. FIG. 12 shows construction of the solid-state imaging apparatus according to the seventh embodiment; the seventh embodiment is different only in pixel construction from the first embodiment shown in FIG. 4A , and the construction of the rest is the same. In particular, included at the inside of a main pixel PIX 11 are: a photoelectric conversion section PD 11 ; a reset switch ME 11 for resetting the photoelectric conversion section PD 11 ; FD (memory C 11 ) for accumulating signal generated at the photoelectric conversion section PD 11 ; a transfer switch MT 11 for controlling a transfer from the photoelectric conversion section PD 11 to FD; a reset switch MR 11 for resetting FD; an amplification section MA 11 for amplifying signal of FD; and a select switch MS 11 for selecting the pixel. Further included at the inside of a sub pixel PIX 21 are: a photoelectric conversion section PD 21 ; a reset switch ME 21 for resetting the photoelectric conversion section PD 21 ; FD (memory C 21 ) for accumulating signal generated at the photoelectric conversion section PD 21 ; a transfer switch MT 21 for controlling a transfer from the photoelectric conversion section PD 21 to FD; a reset switch MR 21 for resetting FD; an amplification section MA 21 for amplifying signal of FD; and a select switch MS 21 for selecting the pixel. These are connected as shown in FIG. 12 . The main pixels and the sub pixels are then two-dimensionally arranged (2 rows by 2 columns in the illustrated example) on every other row to form a pixel section. It should be noted that the constituent components of the other main pixel PIX 12 , and sub pixel PIX 22 of the pixel section are denoted by those numerals that correspond to row and column of each pixel. The transfer switches MT 11 , MT 12 of the main pixels PIX 11 , PIX 12 of the first row are controlled by transfer control signal φTX 1 outputted from a vertical scanning circuit 101 , and transfer switches MT 21 , MT 22 of the sub pixels PIX 21 , PIX 22 of the second row are controlled by transfer control signal φTX 2 . The reset switches ME 11 , of the main pixels of the first row are controlled by PD reset control signal φRSP 1 , and the reset switches ME 21 , of the sub pixels of the second row are controlled by PD reset control signal φRSP 2 . The select switches MS 11 , of the main pixels of the first row are controlled by select control signal φSEL 1 , and the select switches MS 21 , of the sub pixels of the second row by select control signal φSEL 2 ; the output signals of selected pixel row are written to a line memory 102 . Subsequently, the output signals stored at the line memory 102 are read out by a horizontal scanning circuit 103 . The operation of the solid-state imaging apparatus having such construction will now be described by way of a timing chart shown in FIG. 13 . At first, PD reset control signals φRSP 1 , φRSP 2 are driven to high level to effect concurrent reset of photoelectric conversion section PD of all pixels, and the PD reset control signals φRSP 1 , φRSP 2 are then brought to low level to start an accumulation of light signal at the photoelectric conversion section PD. In the intervening time, FD reset control signals φRST 1 , φRST 2 are driven to high level to start a reset of FD, and the FD reset control signals φRST 1 , φRST 2 are subsequently brought to low level to end the reset of FD. Subsequently, transfer control signal φTX 1 to the main pixels of the first row is driven to high level to end the accumulation time of the photoelectric conversion section PD and effect a transfer to FD of light signal of the photoelectric conversion section PD. The transfer control signal φTX 2 to the sub pixels of the second row on the other hand maintains low level so as not to effect a transfer of light signal of the photoelectric conversion section PD of the second row. Next, pixel rows selected by select control signal in the manner of time series are sequentially read out. In particular at first, the select control signal φSEL 1 is driven to high level to output light signals of the pixel (main pixel) row of the first row to the line memory 102 , and the select control signal φSEL 1 is then brought to low level to end the outputting. Next, select control signal φSEL 2 is driven to high level to output pixel signals of the pixel (sub pixel) row of the second row to the line memory 102 . The output signal of the main pixel outputted in this manner is signal where FD leak signal (referred to as Vsf in this description) and signal due to leakage light (referred to as Vse in this description), i.e. noise signals are added to light signal Vp accumulated at the photoelectric conversion section PD. Supposing signal of the main pixel as Vs 7 , it is represented in symbols as in the following equation (17). Vs 7= Vp+Vsf+Vse   (17) Further, the output signal of the sub pixel is signal where FD leak signal Vnf and leakage light signal Vne, i.e. noise signals, and FD variance signal Vnb are added up so that the output signal of the sub pixel supposed as Vn 7 is represented in symbols as in the following equation (18). Vn 7= Vnf+Vne+Vnb   (18) In this case, since the main pixel and the sub pixel are read out substantially at the same point in time, the FD leak signals and the leakage light signals are respectively of substantially the same value and are represented by equation of symbols as: Vsf=Vnf, Vse=Vne. Accordingly, differential image data obtained by difference between the signals of the main pixel and the sub pixel is represented in symbols as in the following equation (19). Vs 7− Vn 7 =Vpd−Vnb   (19) The operation of acquiring the correction image data in this embodiment is the same as in the first to fourth embodiments and will not be described. It is then possible to acquire the light signal Vp alone and obtain image having excellent S/N by acquiring data after correction from the above differential image data and correction image data. Embodiment 8 An eighth embodiment will now be described. FIG. 14 shows construction of the solid-state imaging apparatus according to the eighth embodiment. This embodiment is different from the first embodiment shown in FIG. 4A in disposition of main pixels 1 and sub pixels 2 in the pixel section, and the construction of the rest is similar to the first embodiment. In this embodiment as shown in FIG. 14 , main pixel rows are disposed in succession of a plurality of rows (3 rows in the illustrated example), and one sub pixel row is disposed next to it. Further as shown in FIG. 15 , it is also possible to dispose main pixels 1 and sub pixels 2 separately in column direction. In FIG. 15 , one sub pixel column is disposed after disposing 3 main pixel columns in succession. Furthermore, it is also possible as shown in FIG. 16 to dispose main pixels 1 in two-dimensional succession and to dispose sub pixel column adjacently to it. In the example of FIG. 16 , the main pixels 1 are two dimensionally disposed (10 rows by 9 columns in the illustrated example), and one column of sub pixels 2 is disposed on the right-side end thereof. The construction of the reset of the solid-state imaging apparatus including construction of each pixel and the operation of acquiring data after correction are the same as in the first to seventh embodiments and will not be described. By disposing the main pixels 1 and the sub pixels 2 as the above, the number of main pixels can be increased so as to obtain image having high quality. Embodiment 9 A ninth embodiment will now be described. Also in the ninth embodiment as shown in FIG. 17 , the disposition of main pixels and sub pixels in the pixel section is specifically determined, and the construction of the rest is similar to the first embodiment. In particular, a pixel unit 3 is formed of eight main pixels 1 that surround one sub pixel 2 , and such pixel units 3 are two dimensionally arranged (3 rows by 3 columns in the illustrated example) to form a pixel section. The construction of solid-state imaging apparatus other than the construction of pixel section and the operation of acquiring data after correction are the same as in the first to seventh embodiments and will not be described. By disposing the main pixels 1 and sub pixels 2 in this manner, the number of main pixels can be increased similarly to the eighth embodiment so as to obtain image having high quality. According to the first aspect of the invention as has been described by way of the above embodiments, it is possible to achieve a solid-state imaging apparatus where image data having high S/N can be acquired by setting simultaneous accumulation time to all pixels so as to reduce a fixed noise when differentiating between a first pixel signal and a second pixel signal. According to the second aspect, characteristic variance can be corrected by using the same pixel construction for the first pixel and for the second pixel. According to the third aspect, since absence of photoelectric conversion section makes it possible to reduce area of the second pixel, area of the photoelectric conversion section of the first pixel can be made larger so as to acquire an image having excellent S/N. According to the fourth aspect, the number of first pixels can be increased to obtain an image having high quality. According to the fifth aspect, an image having more excellent S/N can be obtained by providing function for computing characteristic variance data with considering accumulation time. According to the sixth aspect, by providing a function for acquiring characteristic variance data of the first pixel and the second pixel by a very short accumulation time, it is possible to reduce a time required for acquiring characteristic variance data, and at the same time an image having excellent S/N can be obtained. According to the seventh aspect, a noise can be effectively removed and an image having excellent S/N can be acquired by providing function where characteristic variance data of the first pixel and the second pixel is acquired without accumulating signal associated with object image at the input section in the same accumulation time as when acquiring the differential image data.

A solid-state imaging apparatus including, among other things, a control section that, after simultaneous and concurrent reset of all first and second input sections, effects control so as to cause all the first input sections to concurrently and simultaneously accumulate the signal associated with the object image having the same exposure start timing; a correction data retaining section that retains correction data to correct a characteristic variance between the first input section and the second input section where the correction data is generated by taking a difference between a noise signal of the first input section and a noise signal of the second input section containing the characteristic variance; and a variance correction section that generates a third pixel signal corresponding to a difference between the first pixel signal and the second pixel signal where the characteristic variance is corrected by subtracting the correction data from the third pixel signal.

This application is a continuation-in-part of U.S. Provisional application Ser. No. 60/069592, filed Dec. 12, 1997. TECHNICAL FIELD The present invention relates to substituted triazines which are useful for treating pathological states which arise from or are exacerbated by angiogenesis, to pharmaceutical compositions comprising these compounds, and to methods of inhibiting angiogenesis in a mammal. BACKGROUND OF THE INVENTION Angiogenesis, the process by which new blood vessels are formed, is essential for normal body activities including reproduction, development and wound repair. Although the process is not completely understood, it is believed to involve a complex interplay of molecules which regulate the growth of endothelial cells (the primary cells of capillary blood vessels). Under normal conditions, these molecules appear to maintain the microvasculature in a quiescent state (i.e. one of no capillary growth) for prolonged periods which may last for as long as weeks or, in some cases, decades. When necessary (such as during wound repair), these same cells can undergo rapid proliferation and turnover within a 5 day period (Folkman, J. and Shing, Y., The Journal of Biological Chemistry, 267(16), 10931-10934, (1992) and Folkman, J. and Klagsbrun, M., Science, 235,442-447 (1987). Although angiogenesis is a highly regulated process under normal conditions, many diseases (characterized as angiogenic diseases) are driven by persistent unregulated angiogenesis. Otherwise stated, unregulated angiogenesis may either cause a particular disease directly or exacerbate an existing pathological condition. For example, ocular neovascularization has been implicated as the most common cause of blindness and dominates approximately twenty eye diseases- In certain existing conditions, such as arthritis, newly formed capillary blood vessels invade the joints and destroy cartilage. In diabetes, new capillaries formed in the retina invade the vitreous, bleed, and cause blindness. Growth and metastasis of solid tumors are also dependent on angiogenesis (Folkman, J., Cancer Research, 46, 467-473 (1986), Folkman, J., Journal of the National Cancer Institute, 82, 4-6 (1989). It has been shown, for example, that tumors which enlarge to greater than 2 mm must obtain their own blood supply and do so by inducing the growth of new capillary blood vessels. Once these new blood vessels become embedded in the tumor, they provide a means for tumor cells to enter the circulation and metastasize to distant sites such as liver, lung or bone (Weidner, N., et al., The New England Journal of Medicine, 324(1), 1-8 (1991). Several angiogenesis inhibitors are currently under development for use in treating angiogenic diseases (Gasparini, G. and Harris, A. L., J. Clin. OncoL-, 13(3): 765-782, 1995), but there are disadvantages associated with these compounds. Suramin, for example, is a potent angiogenesis inhibitor but causes severe systemic toxicity in humans at doses required for antitumor activity. Compounds such as retinoids, interferons and antiestrogens are relatively safe for human use but have weak antiangiogenic effects. Irsogladine, an anti-tumor drug with low toxicity, has only weak anti-angiogenic effects. Thus there is still a need for compounds -useful in treating angiogenic diseases in mammals. SUMMARY OF THE INVENTION In one embodiment of the present invention are disclosed compounds having Formula I: ##STR2## or pharmaceutically acceptable salts or prodrugs thereof, wherein R 1 , R 2 , R 3 , and R 4 are independently selected from the group consisting of hydrogen, C 1 -C 20 alkyl, and C 1 -C 20 alkanoyl; or R 1 and R 2 together with the nitrogen atom to which they are attached form a ring independently selected from the group consisting of morpholine, piperidine, piperazine, and pyrrolidine; or R 3 and R 4 together with the nitrogen atom to which they are attached form a ring independently selected from the group consisting of morpholine, piperidine, piperazine, and pyrrolidine; A is selected from the group consisting of heterocycle, (heterocycle)--C 1 -C 20 -alkyl, C 3 -C 10 cycloalkyl, C 6 -C 15 spiroalkyl, and --B--L--Y; B and Y are independently aryl, C 3 -C 10 cycloalkyl, C 4 -C 10 cycloalkenyl, heterocycle, or C 6 -C 15 spiroalkyl; L is a covalent bond, --C(═W)--, C 1 -C 20 alkylene, --NR 5 --, --NR 6 C(X)NR 7 --, C 2 -C 20 alkynylene, C 2 -C 20 alkenylene, --O--, --S(O)t--, --NR 6 C(X)--, --C(X)NR 6 --, --NR 6 SO 2 NR 7 --, --NR 6 SO 2 --, --SO 2 NR 6 --, or --O--C--(R 100 )(R 200 ); R 5 is hydrogen, C 1 -C 20 alkyl, C 1 -C 20 alkanoyl, and C 1 -C 20 arylalkyl; R 6 and R 7 are independently hydrogen, C 1 -C 20 alkyl, and aryl-C 1 -C 20 -alkyl; R 100 and R 200 are independently selected from the group consisting of hydrogen, C 1 -C 20 alkyl, and C 1 -C 20 alkanoyl; W is O, S, or (═N--O--R 6 ); X is O or S; t is 0-2; each L is shown with its left end attached to B and its right end attached to Y; and at each occurence, aryl, cycloalkyl, cycloalkenyl, heterocycle, spiroalkyl, alkylene, and (heterocycle)alkyl may be optionally substituted with 1-3 substituents independently selected from C 1 -C 20 alkoxy, C 1 -C 20 alkyl, amino, aryl, azido, cyano, halo, C 1 -C 20 haloalkyl, heterocycle, nitro, or R 10 and R 11 wherein R 10 and R 11 together are ##STR3## wherein A and D are independently oxygen or S(O) t and n is 2-3, with the proviso that when B and Y are unsubstituted phenyl and L is a covalent bond, then at least one of R 1 , R 2 , R 3 , and R 4 is other than hydrogen, and with the proviso that when L is a covalent bond and one of B or Y is unsubstituted imidazole and the other is unsubstituted phenyl, then at least one of R 1 , R 2 , R 3 , and R 4 is other than hydrogen. In another embodiment of the invention are disclosed methods of treating diseases comprising administering an effective amount of a compound having Formula I. In yet another embodiment of the invention are disclosed pharmaceutical compositions containing compounds of Formula I. Compounds of this invention include, but are not limited to, a compound selected from the group consisting of: 6-[1-(diphenylmethyl)-3-azetidinyl]-1,3,5-triazine-2,4-diamine, 6-(1-phenyl-4-piperidinyl)-1,3,5-triazine-2,4-diamine, trans-6-(4-phenylcyclohexyl)-1,3,5-triazine-2,4-diamine, 6-[3-(1H-pyrrol-1-yl)phenyl]-1,3,5-triazine-2,4-diamine, cis/trans-6-(3-phenylcyclobutyl)-1,3,5-triazine-2,4-diamine, 6-[1,1'-biphenyl]-2-yl-1,3,5-triazine-2,4-diamine, 6-(4'-nitro[1,1'-biphenyl]-4-yl)-1,3,5-triazine-2,4-diamine, 6-[4-(4-pentylcyclohexyl)phenyl]-1,3,5-triazine-2,4-diamine, 6-(4-phenoxyphenyl)-1,3,5-triazine-2,4-diamine, N-cyclohexyl-N'-[4-(4,6-diamino-1,3,5-triazin-2-yl)phenyl]urea, (4,6-diamino-1,3,5-triazine-2-yl)phenylmethenone, N-[4-(4,6-diamino-1,3,5-triazin-2-yl)phenyl]-N'-phenyl urea, 6-(1,4-dioxa-8-azaspiro[4,5]dec-8-yl)-1,3,5-triazine-2,4-diarnine, 6-(4'-pentyl[1,1'-biphenyl]-4-yl)-1,3,5-triazine-2,4-diamine, 6-[4'-(pentyloxy)[1,1'-biphenyl]-4-yl]-1,3,5-triazine-2,4-diamine, 6-(6-methoxy-2-benzothiazolyl)-1,3,5-triazine-2,4-diamine, 6-(4'-amino[1,1'-biphenyl]-4-yl)-1,3,5-triazine-2,4-diamine, 6-[4-(5-oxazolyl)phenyl]-1,3,5-triazine-2,4-diarnine, 6-[4-[[5-(trifluoromethyl)-2-pyridinyl]oxy]phenyl]-1,3,5-triazine-2,4-diamine, 4'-(4,6-diamino-1,3,5-trazine-2-yl)[1,1'-biphenyl]-4-carbonitrile, 6-(4'-methoxy[1,1'-biphenyl]-4-yl)-1,3,5-triazine-2,4-diamine, 6-(4'-fluoro[1,1'-biphenyl]-4-yl)-1,3,5-triazine-2,4-diamine N-[4-(4,6-diamino-1,3,5-triazin-2-yl)phenyl]benzenesulfonamide, 6-[1-([1,1'-biphenyl]-4-yl)-4-piperidinyl]-1,3,5-triazine-2,4-diamine, N-[4-(4,6-diamino-1,3,5-triazin-2-yl)phenyl]-2-naphthalenesulfonamide, 2,5-dichloro-N-[4-(4,6-diamino-1,3,5-triazin-2-yl)phenyl]benzenesulfonamide 6-(1-phenylcyclohexyl)-1,3,5-triazine-2,4-diamine, 6-[1-( 4 -methoxyphenyl)-4-piperidinyl]-1,3,5-triazine-2,4-diamine, 6-[2-[4-(trifluoromethyl)phenyl]-4-thiazolyl]-1,3,5-triazine-2,4-diamine, 6-[1-(4-methoxyphenyl)cyclohexyl]-1,3,5-triazine-2,4-diamine, 6-[4-(2-thienyl)phenyl]1,3,5-triazine-2,4-diamine, 6-[4-(phenylethynyl)phenyl]1,3,5-triazine-2,4-diamine, N,N '-(6-[1,1'-biphenyl]-4-yl-1,3,5-triazin-2,4-diyl)bis[acetamide], N-(4-amino-6-[1,1'-biphenyl]-4-yl-1,3,5-triazin-2-yl)acetamide, N-[4-(4,6-diamino-1,3,5-triazin-2-yl)phenyl]-1-naphthalenesulfonamide, 6-(4'-azido[1,1'-biphenyl]-4-yl)-1,3,5-triazine-2,4-diamine, 6-[4-(4-morpholinylsulfonyl)phenyl]-1,3,5-triazine-2,4-diamine, 6-[4-(2-furanyl)phenyl]-1,3,5-triazine-2,4-diamine, N,N'-[6-(4-phenoxyphenyl)-1,3,5-triazine-2,4-diyl]bis[acetamide], N-[4-amino-6-(4-phenoxyphenyl)-1,3,5-triazin-2-yl]acetamide, 6 -(5-phenyl-2-furanyl)-1,3,5-triazine-2,4-diamine, 6-(5-phenyl-2-thienyl)-1,3,5-triazine-2,4-diamine, N,N'-[6-(4-phenylcyclohexyl)-1,3,5-triazin-2,4-diyl]bis[acetamide], N-[4-amino-6-(4-phenylcyclohexyl)-1,3,5-triazin-2-yl]acetamide, 6-(4-phenyl-1-naphthalenyl)-1,3,5-triazine-2,4-diamine, 6-[4-(phenylthio)phenyl]-1,3,5-triazine-2,4-diamine, 6-(2-quinolinyl)-1,3,5-triazine-2,4-diamine, 6-(3-quinolinyl)-1,3,5-triazine-2,4-diamine, 6-(benzo[b]thien-2-ylmethyl)-1,3,5-triazine-2,4-diamine, 6-(2,2-dimethyl-2H-1-benzopyran-6-yl)-1,3,5-triazine-2,4-diamine, 6-(1-isoquinolinyl)-1,3,5-triazine-2,4-diamine (6-(2,3-dihydro-1,4-benzodioxin-2-yl)-1,3,5-triazine-2,4-diamine, 6-(tricyclo[3.3.1.1 3 .7 ]decan-1-yl)-1,3,5-triazine-2,4-diamine, (+/-)-4-(4,6-diamino-1,3,5-triazine-2-yl)-α-phenylbenzenemethanol, 6-(2,3-dihydro-1,4-benzodioxin-6-yl)-1,3,5-triazine-2,4-diamine, 6-(1-azabicyclo[2.2.2)octan-4-yl)-1,3,5-triazine-2,4-diamine, 6-[4-(phenylsulfinyl)phenyl]1,3,5-triazine-2,4diamine, 6-[4-(phenylsulfonyl)phenyl]-1,3,5-triazine-2,4-diamine, [4-(4,6-diamino-1,3,5-triazine-2-yl)phenyl]phenylmethanone, oxime, 6-pyrazinyl-1,3,5-triazine-2,4-diamine, 2,4-diamino-6-[(4-phenylethenyl)phenyl]-1,3,5-triazine, 2,4-diamino-6-[(4-(2-nitrophenyl)ethenyl)phenyl]-1,3,5-triazine, 6-[1,1'-biphenyl]-4-yl-N,N'-dimethyl-1,3,5-triazine-2,4-diamine, 6-[1,1'-biphenyl]-4-yl-N-methyl-1,3,5-triazine-2,4-diamine, 6-(bicyclo[2.2.1]hept-2-yl)-1,3,5-triazine-2,4-diamine, 6-[1,1'-biphenyl3,4-yl-N,N'-diethyl-1,3,5-triazine-2,4-diamine, 6-(2'-nitro[1,1'-biphenyl]-4-yl)-1,3,5-triazine-2,4-diamine, 6-(6-methyl-3-pyridinyl)-1,3,5-triazine-2,4-diamine, 6-(6-chloro-3-pyridinyl)-1,3,5-triazine-2,4-diamine, 6-(5-bromo-3-pyridinyl)-1,3,5-triazine-2,4-diamine, 6-(2,3-dihydro-2,2,3,3-tetrafluoro-1,4-benzodioxin-6-yl)-1,3,5-triazine-2,4-diamine, 6-[4-[(4-chlorophenyl)methoxy]phenyl]-1,3,5-triazine-2,4-diamine, 6-[4-(1-piperidinylsulfonyl)phenyl]-1,3,5-triazine-2,4-diamine, 6-(1-benzoyl-4-piperidinyl)-1,3,5-triazine-2,4-diamine, 6-[1-(phenylmethyl)-4-piperidinyl]-1,3,5-triazine-2,4-diamine, N,N'-diacetyl-6-[4-(phenylsulfonyl)phenyl]-1,3,5-triazine-2,4-diamine, N-acetyl-6-[4-(phenylsulfonyl)phenyl]-1,3,5-triazine-2,4-diamine, and 6-(2-piperidin-1-ylphenyl)-1,3,5-triazine-2,4-diamine. DETAILED DESCRIPTION OF THE INVENTION Definition of Terms The term "alkanoyl" as used herein represents an alkyl group of 1-20 carbon atoms attached to the parent molecular group through a carbonyl group. The term "alkoxy" as used herein represents an alkyl group of 1-20 carbon atoms attached to the parent molecular group through an oxygen atom. The term "alkyl" as used herein represents a monovalent group of 1-20 carbon atoms derived from a straight or branched chain saturated hydrocarbon. The alkyl groups of this invention may be substituted with 1-3 substituents independently selected from aryl or heterocycle. The term "alkylene" as used herein represents a saturated divalent group of 1-20 carbon atoms derived from a straight or branched chain saturated hydrocarbon. The alkylene groups of this invention may be optionally substituted with oxo, thioxo, (═N--O--R 6 ), or --OR 6 . The term "alkenylene" as used herein represents an unsaturated divalent group of 2-20 carbon atoms derived from a straight or branched chain alkene. The term "alkynylene" as used herein represents an unsaturated divalent group of 2-20 carbon atoms derived from a straight or branched chain alkyne. The term "amino" as used herein represents --NH 2 . The term "aryl" as used herein represents a mono- or bicyclic carbocyclic ring system derived from one or two aromatic rings. The aryl groups of this invention may be optionally substituted with 1-4 substituents independently selected from alkoxy, alkyl, amino, aryl, azido, cyano, halo, haloalkyl, heterocycle, or nitro. The term "arylalkyl" as used herein represents an aryl group attached to the parent molecular group through an alkyl group. The term "azido" as used herein represents --N 3 . The term "cyano" as used herein represents --CN. The term "cycloalkyl" as used herein represents a saturated monovalent group of 3-10 carbon atoms derived from a cyclic or bicyclic hydrocarbon. The cycloalkyl groups of this invention may be optionally substituted with 1-3 substituents independently selected from alkyl, aryl, or heterocycle. The term "cycloalkenyl" as used herein represents an unsaturated monovalent group of 4-10 carbon atoms derived from a cyclic or bicyclic alkene. The cycloalkenyl groups of this invention may be optionally substituted with 1-3 substituents independently selected from alkyl, aryl, or heterocycle. The term "halo" as used herein represents F, Cl, Br, or I. The term "haloalkyl" as used herein represents an alkyl group to which is attached at least one halogen atom. The term "heterocycle," as used herein, represents a 4-, 5-, 6-, or 7-membered ring containing one, two, or three heteroatoms independently selected from the group consisting of nitrogen, oxygen, and sulfur. The 4- and 5-membered rings have zero to two double bonds and the 6- and 7-membered rings have zero to three double bonds. These heterocycles include benzimidazolyl, benzofura nyl, benzothiazolyl, benzothienyl, benzoxazolyl, dihydrothienyl, dihydroindolyl, dihydrofuranyl, dihydropyranyl, dithiazolyl, furyl, homopiperidinyl, imidazolyl, imidazolinyl, imidazolidinyl, isothiazolyl, isothiazolidinyl, isoquinolinyl, indolyl, isoxazolyl, isoxazolidinyl, isothiazolyl, morpholinyl, oxazolidinyl, oxazolyl, piperazinyl, piperidinyl, pyranyl, pyrazinyl, pyrazolidinyl, pyrazolinyl, pyrazolyl, pyridyl, pyrrolidinyl, pyrrolinyl, pyrrolyl, pyridazinyl, pyrimidinyl, pyrimidyl, quinolinyl, tetrahydrofuranyl, tetrahydroisoquinolyl, tetrahydroquinolyl, tetrahydrothienyl, tetrazolyl, thiadiazolyl, thiazolidinyl, thiazolyl, thienyl, thiomorpholinyl, triazolyl, oxadiazolyl, and the like. Heterocycles also includes bicyclic, tricyclic, and tetracyclic groups in which any of the aformentioned heterocyclic rings is fused to one or two rings independently selected from an aryl ring, a cyclohexane ring, a cyclohexene ring, a cyclopentane ring, a cyclopentene ring, or another monocyclic heterocyclic ring. These heterocycles include benzofuryl, benzothienyl, indolyl, isoquinolyl, quinolyl, tetrahydroquinolyl, and the like. Heterocyclics also include compounds of the formula ##STR4## wherein X* is selected from --CH 2 --, --CH 2 )--and --O--, and Y* is selected from --C(O)-- and --(C(R") 2 ), --wherein R" is hydrogen or alkyl of one to four carbon atoms and v is 1-3. These heterocycles include 1,3-benzodioxolyl, 1,4-benzodioxanyl, and the like. The heterocycles of this invention may be optionally substituted with 1-4 substituents independently selected from alkoxy, aLkyl, amino, aryl, azido, cyano, halo, haloalkyl, heterocycle, nitro, or R 10 and R 11 wherein R 10 and R 11 together are ##STR5## wherein A and D are independently oxygen or S(O) t and n is 2-3. The term "(heterocycle)alkyl" as used herein represents an alkyl group substituted by a heterocycle. The (heterocycle)alkyl of this invention may be optionally substituted with aryl or heterocycle. The term "hydroxy" as used herein represents --OH. The term "nitro" as used herein represents --NO 2 . The term "oxo" as used herein represents (═O). The term "pharmaceutically acceptable prodrugs" as used herein represents those prodrugs of the compounds of the present invention which are, within the scope of sound medical judgement, suitable for use in contact with with the tissues of humans and lower animals with undue toxicity, irritation, allergic response, and the like, commensurate with a reasonable benefit /risk ratio, and effective for their intended use, as well as the zwitterionic forms, where possible, of the compounds of the invention. The term "prodrug," as used herein, represents compounds which are rapidly transformed in vivo to the parent compound of the above formula, for example, by hydrolysis in blood. A thorough discussion is provided in T. Higuchi and V. Stella, Pro-drugs as Novel Delivery Systems, Vol. 14 of the A.C.S. Symposium Series, and in Edward B. Roche, ed., Bioreversible Carriers in Drug Design, American Pharmaceutical Association and Pergamon Press, 1987, both of which are incorporated herein by reference. The term "spiroalkyl" as used herein represents an alkylene diradical, both ends of which are bonded to the same carbon atom of the parent group to form a spirocyclic group. The spiroalkyl groups of this invention may be optionally substituted with 1-2 substituents independently selected from alkyl, aryl, or heterocycle. The term "thioxo" as used herein represents (═S). Asymmetric or chiral centers may exist in the compounds of the present invention. The present invention contemplates the various stereoisomers and mixtures thereof. Individual stereoisomers of compounds of the present invention are prepared synthetically from commercially available starting materials which contain asymmetric or chiral centers or by preparation of mixtures of enantiomeric compounds followed by resolution well-known to those of ordinary skill in the art. These methods of resolution are exemplified by (1) attachment of a racemic mixture of enantiomers, designated (+/-), to a chiral auxiliary, separation of the resulting diastereomers by recrystallization or chromatography and liberation of the optically pure product from the auxiliary or (2) direct separation of the mixture of optical enantiomers on chiral chromatographic columns. Pure enantiomers are designated herein by the symbols "R" or "S," depending on the configuration of subsitiuents around the chiral carbon atom. Geometric isomers may also exist in the compounds of the present invention. The present invention contemplates the various geometric isomers and mixtures thereof resulting from the arrangement of substituents around a carbon-carbon double bond or arrangement of substituents around a carbocyclic ring. Substituents around a carbon-carbon double bond are designated as being in the Z or E configuration wherein the term "Z" represents substituents on the same side of the carbon-carbon double bond and the term "E" represents substituents on opposite sides of the carbon-carbon double bond. The arrangement of substituents around a carbocyclic ring are designated as cis or trans wherein the term "cis" represents substituents on the same side of the plane of the ring and the term "trans" represents substituents on opposite sides of the plane of the ring. Mixtures of compounds wherein the substitutients are disposed on both the same and opposite sides of plane of the ring are designated cis/trans. Endothelial Cell Migration Assay The endothelial cell migration assay was performed essentially as described by Polverini, P. J. et al., Methods Enymol, 198: 440-450 (1991). Briefly, Human Microvascular Endothelial Cells (HMVEC) were starved overnight in DMEM (Dulbecco's Modified Eagle Medium) containing 0.1% bovine serum albumin (BSA). Cells were then harvested with trypsin and resuspended -in DMEM with 0.1% BSA at a concentration of 1.5×10 6 cells/mL. Cells were added to the bottom of a 48-well modified Boyden chamber (Nucleopore Corporation, Cabin John, Md.). The chamber was assembled and inverted, and cells were allowed to attach for 2 hours at 37° C. to polycarbonate chemotaxis membranes (5 μm pore size) that had been soaked in 0.1% gelatin overnight and dried. The chamber was then reinverted and basic fibroblast growth factor (bFGF) and test substances were added to the wells of the upper chamber (to a total volume of 50 μL); the apparatus was then incubated for 4 hours at 37° C. Membranes were recovered, fixed and stained (DiffQuick, Fisher Scientific, Pittsburgh, Pa.) and the number of cells that had migrated to the upper chamber per 10 high power fields were counted. Background migration to DMEM +0.1% BSA was subtracted and the data reported as the number of cells migrated per 10 high power fields (400X) or when results from multiple experiments were combined, as the percent inhibition of migration compared to a positive control. The results are shown in Table 1. TABLE 1______________________________________Inhibitory Potencies Against bFGF Induced Human Microvascular Endothelial Cell Migration of Representative Compounds Example % inhibition at (nM)______________________________________Irsogladine 53% (600 nM) 1 20 (600) 3 100 (600) 4 62 (600) 6 95 (600) 7 100% (600 nM) 8 30 (600) 9 29 (600) 10 29 (600) 12 36 (600) 13 53 (600) 47 65 (600) 48 55 (600) 49 14 (600) 50 100 (600) 51 100 (600) 52 100 (600) 53 85 (600) 55 84 (600) 56 30 (600) 58 100 (600) 60 100 (600) 63 79 (500) 65 32 (200) 68 73 (500) 69 39 (500) 74 82 (500) 75 16 (500) 76 33 (500) 77 50 (500)______________________________________ The compounds of the invention, including but not limited to those specified in the examples, possess anti-angionenic activity. As angiogenesis inhibitors, such compounds are useful in the treatment of both primary and metastatic solid tumors and carcinomas of the breast; colon; rectum; lung; oropharynx; hypopharynx; esophagus; stomach; pancreas; liver; gallbladder; bile ducts; small intestine; urinary tract including kidney, bladder and urothelium; female genital tract including cervix, uterus, ovaries, choriocarcinoma and gestational trophoblastic disease; male genital tract including prostate, seminal vesicles, testes and germ cell tumors; endocrine glands including thyroid, adrenal, and pituitary; skin including hemangiomas, melanomas, sarcomas arising from bone or soft tissues and Kaposi's sarcoma; tumors of the brain, nerves, eyes, and meninges including astrocytomas, gliomas, glioblastomas, retinoblastomas, neuromas, neuroblastomas, Schwannomas and meningiomas; solid tumors arising from hematopoietic malignancies such as leukemias and including chloromas, plasmacytomas, plaques and tumors of mycosis fungoides and cutaneous T-cell-lymphoma/leukemia; lymphomas including both Hodgkin's and non-Hodgkin's lymphomas; prophylaxis of autoimmune diseases including rheumatoid, immune and degenerative arthritis; ocular diseases including diabetic retinopathy, retinopathy of prematurity, corneal graft rejection, retrolental fibroplasia, neovascular glaucoma, rubeosis, retinal neovascularization due to macular degeneration and hypoxia; abnormal neovascularization conditions of the eye; skin diseases including psoriasis; blood vessel diseases including hemagiomas and capillary proliferation within atherosclerotic plaques; Osler-Webber Syndrome; myocardial angiogenesis; plaque neovascularization; telangiectasia; hemophiliac joints; angiofibroma; wound granulation; diseases characterized by excessive or abnormal stimulation of endothelial cells including intestinal adhesions, Crohn's disease, atherosclerosis, scleroderma and hypertrophic scars (i.e. keloids) and diseases which have angiogenesis as a pathologic consequence including cat scratch disease (Rochele minalia quintosa) and ulcers (Helicobacterpylori). Another use is as a birth control agent which inhibits ovulation and establishment of the placenta. The compounds of the present invention may also be useful for the prevention of metastases from the tumors described above either when used alone or in combination with radiotherapy and/or other chemotherapeutic treatments conventionally administered to patients for treating cancer. For example, when used in the treatment of solid tumors, compounds of the present invention may be administered with chemotherapeutic agents such as alpha inteferon, COMP (cyclophosphamide, vincristine, methotrexate and prednisone), etoposide, mBACOD (methortrexate, bleomycin, doxorubicin, cyclophosphamide, vincristine and dexamethasone), PRO-MACE/MOPP (prednisone, methotrexate (wl leucovin rescue), doxorubicin, cyclophosphamide, taxol, etoposide/mechlorethamine, vincristine, prednisone and procarbazine), vincri.stine, vinblastine, angioinhibins, TNP-470, pentosan polysulfate, platelet factor 4, angiostatin, LM-609, SU-101, CM-101, Techgalan, thalidomide, SP-PG and the like. Other chemotherapeutic agents include alkylating agents such as nitrogen mustards including mechloethamine, melphan, chlorambucil, cyclophosphamide and ifosfamide; nitrosoureas including carmustine, lomustine, semustine and streptozocin; alkyl sulfonates including busulfan; triazines including dacarbazine; ethyenimines including thiotepa and hexamethylmelamine; folic acid analogs including methotrexate; pyrimidine analogues including 5-fluorouracil, cytosine arabinoside; purine analogs including 6-mercaptopurine and 6-thioguanine; antitumor antibiotics including actinomycin D; the anthracyclines including doxorubicin, bleomycin, mitomycin C and methramycin; hormones and hormone antagonists including tamoxifen and cortiosteroids and miscellaneous agents including cisplatin and brequinar. The compounds of the present invention may be used in the form of pharmaceutically acceptable salts derived from inorganic or organic acids. By "pharmaceutically acceptable salt" is meant those salts which are, within the scope of sound medical judgement, suitable for use in contact with the tissues of humans and lower animals without undue toxicity, irritation, allergic response and the like and are commensurate with a reasonable benefit/risk ratio. Pharmaceutically acceptable salts are well-known in the art. For example, S. M. Berge, et al. describe pharmaceutically acceptable salts in detail in J. Pharmaceutical Sciences, 1977, 66: 1 et seq. The salts may be prepared in situ during the final isolation and purification of the compounds of the invention or separately by reacting a free base function with a suitable acid. Representative acid addition salts include, but are not limited to acetate, adipate, alginate, citrate, aspartate, benzoate, benzenesulfonate, bisulfate, butyrate, camphorate, camphorsufonate, digluconate, glycerophosphate, hemisulfate, heptanoate, hexanoate, fumarate, hydrochloride, hydrobromide, hydroiodide, 2-hydroxyethansulfonate (isethionate), lactate, maleate, methanesulfonate, nicotinate, 2-naphthalenesulfonate, oxalate, pamoate, pectinate, persulfate, 3-phenylpropionate, picrate, pivalate, propionate, succinate, tartrate, thiocyanate, phosphate, glutamate, bicarbonate, p-toluenesulfonate and undecanoate. Also, the basic nitrogen-containing groups can be quaternized with such agents as lower alkyl halides such as methyl, ethyl, propyl, and butyl chlorides, bromides and iodides; dialkyl sulfates like dimethyl, diethyl, dibutyl and diamyl sulfates; long chain halides such as decyl, lauryl, myristyl and stearyl chlorides, bromides and iodides; arylalkyl halides like benzyl and phenethyl bromides and others. Water or oil-soluble or dispersible products are thereby obtained. Examples of acids which may be employed to form pharmaceutically acceptable acid addition salts include such inorganic acids as hydrochloric acid, hydrobromic acid, sulphuric acid and phosphoric acid and such organic acids as oxalic acid, maleic acid, succinic acid and citric acid. Basic addition salts can be prepared in situ during the final isolation and purification of compounds of this invention by reacting a carboxylic acid-containing moiety with a suitable base such as the hydroxide, carbonate or bicarbonate of a pharmaceutically acceptable metal cation or with ammonia or an organic primary, secondary or tertiary amine. Phar mnaceutically acceptable salts include, but are not limited to, cations based on alkali metals or alkaline earth metals such as lithium, sodium, potassium, calcium, magnesium and aluminum salts and the like and nontoxic quaternary ammonia and amine cations including ammonium, tetramethylammonium, tetraethylammonium, methylamine, dimethylamine, trimethylamine, triethylamine, diethylamine, ethylamine and the like. Other representative organic amines useful for the formation of base addition salts include ethylenediamine, ethanolamine, diethanolamine, piperidine, piperazine and the like. Preferred salts of the compounds of the invention include phosphate, tris and acetate. Compounds of this invention may be combined with pharmaceutically acceptable sustained-release matrices, such as biodegradable polymers, to form therapeutic pocompositions. A sustained-release matrix, as used herein, is a matrix made of materials, usually polymers, which are degradable by enzymatic or acid-base hydrolysis or by dissolution. Once inserted into the body, the matrix is acted upon by enzymes and body fluids. A sustained-release matrix is desirably chosen from biocompatible materials such as liposomes, polylactides (polylactic acid), polyglycolide (polymer of glycolic acid), polylactide co-glycolide (copolymers of lactic acid and glycolic acid) polyanhydrides, poly(ortho)esters, polypeptides, hyaluronic acid, collagen, chondroitin sulfate, carboxylic acids, fatty acids, phospholipids, polysaccharides, nucleic acids, polyamino acids, amino acids such as phenylalanine, tyrosine, isoleucine, polynucleotides, polyvinyl propylene, polyvinylpyrrolidone and silicone. A preferred biodegradable matrix is a matrix of one of either polylactide, polyglycolide, or polylactide co-glycolide (co-polymers of lactic acid and glycolic acid). Compounds of this invention or combinations thereof may be combined with pharmaceutically acceptable excipients or carriers to form therapeutic compositions. A pharmaceutically acceptable carrier or excipient refers to a non-toxic solid, semi-solid or liquid filler, diluent, encapsulating material or formulation auxiliary of any type. The compositions may be administered parenterally, sublingually, intracisternally, intravaginally, intraperitoneally, rectally, bucally or topically (as by powder, ointment, drops, transderrnal patch or iontophoresis device). The term "parenteral," as used herein, refers to modes of administration which include intravenous, intramuscular, intraperitoneal, intrasternal, subcutaneous and intraarticular injection and infusion. Pharmaceutical compositions for parenteral injection comprise pharmaceutically acceptable sterile aqueous or nonaqueous solutions, dispersions, suspensions or emulsions as well as sterile powders for reconstitution into sterile injectable solutions or dispersions just prior to use. Examples of suitable aqueous and nonaqueous carriers, diluents, solvents or vehicles include water, ethanol, polyols (such as glycerol, propylene glycol, polyethylene glycol and the like), carboxymethylcellulose and suitable mixtures thereof, vegetable oils (such as olive oil) and injectable organic esters such as ethyl oleate. Proper fluidity may be maintained, for example, by the use of coating materials such as lecithin, by the maintenance of the required particle size in the case of dispersions and by the use of surfactants. These compositions may also contain adjuvants such as preservatives, wetting agents, emulsifying agents and dispersing agents. Prevention of the action of microorganisms may be ensured by the inclusion of various antibacterial and antifungal agents such as paraben, chlorobutanol, phenol, sorbic acid and the like. It may also be desirable to include isotonic agents such as sugars, sodium chloride and the like. Prolonged absorption of the injectable pharmaceutical form may be brought about by the inclusion of agents, such as aluminum monostearate and gelatin, which delay absorption. Injectable depot forms are made by forming microencapsule matrices of the drug in biodegradable polymers such as polylactide-polyglycolide, poly(orthoesters) and poly(anhydrides). Depending upon the ratio of drug to polymer and the nature of the particular polymer employed, the rate of drug release can be controlled. Depot injectable formulations are also prepared by entrapping the drug in liposomes or microemulsions which are compatible with body tissues. The injectable formulations may be sterilized, for example, by filtration through a bacterial-retaining filter or by incorporating sterilizing agents in the form of sterile solid compositions which can be dissolved or dispersed in sterile water or other sterile injectable media just prior to use. Topical administration includes administration to the skin, mucosa and surfaces of the lung and eye. Compositions for topical administration, including those for inhalation, may be prepared as a dry powder which may be pressurized or non-pressurized. In non-pressurized powder compositions, the active ingredient in finely divided form may be used in admixture with a larger-sized pharmaceutically acceptable inert carrier comprising particles having a size, for example, of up to 100 micrometers in diameter. Suitable inert carriers include sugars such as lactose. Desirably, at least 95% by weight of the particles of the active ingredient have an effective particle size in the range of 0.01 to 10 micrometers. For topical administration to the eye, a compound of the invention is delivered in a pharmaceutically acceptable ophthalmic vehicle such that the compound is maintained in contact with the ocular surface for a sufficient time period to allow the compound to penetrate the corneal and internal regions of the eye, as, for example, the anterior chamber, posterior chamber, vitreous body, aqueous humor, vitreous humor, cornea, iris/cilary, lens, choroid/retina and sclera. The pharmaceutically acceptable ophthalmic vehicle may, for example, be an ointment, vegetable oil or an encapsulating material. Alternatively, a compound of the invention may be injected directly into the vitreous and aqueous humor. The composition may be pressurized and contain a compressed gas such as nitrogen or a liquified gas propellant. The liquified propellant medium and indeed the total composition is preferably such that the active ingredient does not dissolve therein to any substantial extent. The pressurized composition may also contain a surface active agent such as a liquid or solid non-ionic surface active agent or may be a solid anionic surface active agent. It is preferred to use the solid anionic surface active agent in the form of a sodium salt. Compositions for rectal or vaginal administration are preferably suppositories which may be prepared by mixing the compounds of this invention with suitable non-irritating excipients or carriers such as cocoa butter, polyethylene glycol or a suppository wax which are solids at room temperature but liquids at body temperature and therefore melt in the rectum or vaginal cavity and release the active compound. Compounds of the present invention may also be administered in the form of liposomes. As is known in the art, liposomes are generally derived from phospholipids or other lipid substances. Liposomes are formed by mono- or multi-lamellar hydrated liquid crystals that are dispersed in an aqueous medium. Any non-toxic, physiologically acceptable and metabolizable lipid capable of forming liposomes can be used. The present compositions in liposome form may contain, in addition to a compound of the present invention, stabilizers, preservatives, excipients and the like. The preferred lipids are the phospholipids and the phosphatidyl cholines (lecithins), both natural and synthetic. Methods to form liposomes are known in the art. See, for example, Prescott, Ed., Methods in Cell Biology, Volume XIV, Academic Press, New York, N.Y. (1976), p. 33 et seq., which is hereby incorporated herein by reference. When used in the above or other treatments, a therapeutically effective amount of one of the compounds of the present invention may be employed in pure form or, where such forms exist, in pharmaceutically acceptable salt form and with or without a pharmaceutically acceptable excipient. A "therapeutically effective amount" of the compound of the invention means a sufficient amount of the compound to treat an angiogenic disease (for example, to limit tumor growth or to slow or block tumor metastasis) at a reasonable benefit/risk ratio applicable to any medical treatment. It will be understood, however, that the total daily usage of the compounds and compositions of the present invention will be decided by the attending physician within the scope of sound medical judgment. The specific therapeutically effective dose level for any particular patient will depend upon a variety of factors including the disorder being treated and the severity of the disorder; activity of the specific compound employed; the specific composition employed; the age, body weight, general health, sex and diet of the patient; the time of administration; the route of administration; the rate of excretion of the specific compound employed; the duration of the treatment; drugs used in combination or coincidental with the specific compound employed and like factors well known in the medical arts. For example, it is well within the skill of the art to start doses of the compound at levels lower than those required to achieve the desired therapeutic effect and to gradually increase the dosage until the desired effect is achieved. Total daily dose of compounds of this invention to be administered locally or systemically to a human or other mammal host in single or divided doses may be in amounts, for example, from 0.01 to 200 mg/kg body weight daily and more usually 1 to 300 mg/kg body weight. If desired, the effective daily dose may be divided into multiple doses for purposes of administration. Consequently, single dose compositions may contain such amounts or submultiples thereof to make up the daily dose. It will be understood that agents which can be combined with the compound of the present invention for the inhibition, treatment or prophylaxis of angiogenic diseases are not limited to those listed above, but include, in principle, any agents useful for the treatment or prophylaxis of angiogenic diseases. Preparation of Compounds of the Invention Abbreviations Abbreviations which have been used in the descriptions of the scheme and the examples that follow are: DMSO for dimethylsulfoxide, DME for dimethoxyethane, EtOAc for ethyl acetate, and THF for tetrahydrofuran. Synthetic Methods The compounds and processes of the present invention will be better understood in connection with the following synthetic schemes which illustrate the methods by which the compounds of the invention may be prepared. ##STR6## As shown in Scheme 1, the triazine ring of the compounds of Formula I were prepared from condensation of esters with biguanide (Reaction 1) or from condensation of nitrites and cyanoguanidine (Reaction 2). Reaction 2 was performed in a polar, high boiling solvent such as 2-methoxyethanol and in the presence of a strong base such as potassium hydroxide. Reaction 1 was performed in an an alcohol, preferably methanol. The ester and nitrile precursors were purchased from commercial sources or prepared using known chemical transformations. ##STR7## As shown in Scheme 2, selective mono acylation to provide compounds of Formula I was accomplished by heating a diaminotriazine precursor with a carboxylic acid anhydride at elevated temperature, preferably 80-90° C. Alternatively, 2,4-diacylation was accomplished by heating the diaminotriazine precursor with a carboxylic acid anhydride at higher temperatures, preferably 140-160° C. ##STR8## As shown in Scheme 3, 2,4-diamino-6-bromoaryl-triazines were converted to compounds of Formula I using transition metal-catalyzed cross-coupling reactions catalyzed by palladium catalysts such as tetrakis(triphenylphosphine) palladium. Also, conversion of Example 20A to a 2,4-diamino-6-(trialkylstannyl)aryl-triazine by treatment with organotin reagents, preferably hexamethylditin, in the presence of a palladium catalyst such as tetrakis(triphenylphosphine) palladium, followed by cross-coupling with aryl bromides, provided an alternative route to compounds of Formula I. Treatment of Example 20A with ethynyltin reagents such as trimethyl(phenylethylyl)tin in the presence of palladium catalysts such as tetrakis(triphenylphosphine) palladium also provided compounds of Formula I. ##STR9## As shown in Scheme 4, compounds of Formula I were prepared by Friedel Crafts alkylation of aryl groups with a cycloalkenyl nitrile followed by elaboration of the nitrile intermediate as described in Scheme 1 (Reaction 2). ##STR10## As shown in Scheme 5, piperidinyl aryl esters were converted to compounds of Formula I by arylation of isonipecotic acid esters with triarylbismuth reagents in the presence of copper (II) acylates. ##STR11## As shown in Scheme 6, compounds of Formula I were prepared by condensation of bis-tosylates with malonic esters to construct cycloalkane rings, mono-decarboxylated at elevated temperatures, and further processed according to Scheme 1 (Reaction 1). ##STR12## As shown in Scheme 7, diaminotriazines bearing alkyl substituents on the amino groups can be prepared in a controlled and predicable manner by sequential displacement of chlorines from the triazine rin g. The 6-aryl, heteroaryl, or cycloalkyl substituent may be introduced first by nucleophilic addition, for example as a Grignard reagent to cyanuric chloride, or after nitrogen introduction, for example by Pd-catalyzed Suzuki cross coupling with a boronic acid. The compounds and processes of the present invention will be better understood in connection with the following examples, which are intended as an illustration of and not a limitation upon the scope of the invention. EXAMPLE 1 6-[1-(diphenylmethyl)-3-azetidinyl]-1,3,5-triazine-2,4-diamine A solution of 1-(diphenylmethyl)-3-azetidinecarbonitrile (500 mg, 2.01 mmol), dicyandiamide (220 mg, 2.62 mmol) and KOH (34 mg, 0.604 mmol) in 2-methoxyethanol (10 mL) was heated at reflux for 4 hours, diluted with water, and cooled to room temperature. The precipitate was rinsed with water and dried under vacuum to provide the title compound. mp 126-128° C.; MS (DCI/NH 3 ) m/e 333 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 7.3 (d, 4H), 7.2 (t, 4H), 7.05 (t, 2H), 6.5-6.7 (br s, 4H), 4.35 (s, 1H), 3.2-3.3 (m, 3H), 3.1-3.15 (m, 2H); Anal. calcd for C 19 H 20 N 6 . 0.75H 2 O: C, 65.97; H, 6.26; N, 24.29. Found: C, 65.67; H, 5.65; N, 23.84. Example 2 6-(1-phenyl-4-piperidinyl)-1,3,5-triazine-2,4-diamine Example 2A A solution of triphenylbismuth (5.02 g, 11.4 mmol), cupric acetate (1.79 g, 9.85 mmol), and ethyl isonipecotate (1.5 mL, 9.7 mmol) in dichloromethane (100 mL) was stirred at room temperature for 18 hours, diluted with water, and filtered through Celite®. The organic layer was dried (MgSO 4 ), and concentrated. The residue was purified by flash chromatography on silica gel with 0-2% acetone/dichloromethane to provide the designated compound. MS (DCI/NH 3 ) m/e 234 (M+H) + . Example 2B The designated compound was prepared as in Inorganic Synthesis, Volume 7, pp. 56-58 (1963). Example 2C 6-(1-Phenyl-4-piperidinyl)-1,3,5-triazine-2,4-diamine A solution of Examples 2A (0.464 g, 1.99 mmol) and 2B (0.211 g, 2.09 mmol) in methanol (4 mL) was stirred at room temperature for 16 hours. The precipitate was rinsed with methanol, dried under vacuum, and recrystallized from dioxane/ethanol to provide the title compound. mp 202-204° C.; MS (DCI/NH 3 ) m/e 271 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 7.19 (t, 2H), 6.94 (d, 2H), 6.72 (t, 1H), 6.56 (br s, 4H), 4.11 (q, 2H), 3.77 (m, 2H), 2.75 (dt, 2H), 2.41 (m, 1H), 1.79 (m, 2H); Anal. calcd for C 14 H 18 N 6 .0.67H 2 O: C, 59.58; H, 6.90; N, 27.78. Found: C, 59.27; H, 6.79; N, 25.51. Example 3 trans-6-(4-phenylcyclohexyl)-1,3,5-triazine-2,4-diamine Example 3A 4-phenylhexenecarbonitrile A solution of cyclohexenecarbonitrile (9 mL, 80.6 mmol) and benzene (75 mL) was treated portionwise with AlCl 3 (13 g, 97 mmol) then stirred at room temperature for 2 hours. The mixture was poured onto ice and extracted with ethyl acetate. The extract was washed sequentially with water and brine, dried (MgSO 4 ), and concentrated. The residue was distilled at 125° C. (0.6 mm Hg) to provide the title compound. MS (DCI/NH 3 ) m/e 203 (M+NH 4 ) + . Example 3B trans-6-(4-phenylcyclohexyl)-1,3,5-triazine-2,4-diamine Example 3A was processed as in Example 1 to provide the title compound. MS (DCI/NH 3 ) m/e 270 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 7.20-7.32 (m, 4H), 7.12-7.18 (m, 1H), 6.57 (br s, 4H), 2.46 (tt, 1H), 2.32 (tt, 1H), 1.80-1.93 (m, 4H), 1.41-1.66 (m, 4H); Anal. calcd for C 15 H 19 N 5 : C, 66.88; H, 7.11; N, 26.00. Found: C, 66.85; H, 7.00; N, 26.08. Example 4 6-[3-(1H-pyrrol-1-yl)phenyl]-1,3,5-triazine-2,4-diamine 3-(1H-pyrrol-1-yl)benzonitrile was processed as in Example 1 to provide the title compound. mp 164-170° C.; MS (DCI/NH 3 ) m/e 253 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 8.35 (s, 1H), 8.15 (d, 1H), 7.7 (dd, 1H), 7.6-7.5 (m, 1H), 7.3 (t, 3H), 7.0-6.8 (br s, 4H), 6.3-6.25 (m, 2H); Anal. calcd for C 13 H 12 N 6 : C, 61.89; H, 4.79; N, 33.31. Found: C, 62.20; H, 4.56; N, 32.39. Example 5 cis/trans-6-(3-phenylcyclobutyl)-1,3,5-triazine-2,4-diamine A solution of cis/trans-methyl 3-phenylcyclobutane-1-carboxylate, prepared as in J. Am. Chem. Soc. 1985, 107, 7247-7257, was processed as in Example 2C to provide the title compounds. mp 98-102° C.; 1 H NMR (300 MHz, DMSO-d 6 ) δ 7.31 (m, 4H), 7.19 (m, 1H), 6.60 (m, 4H), 3.62 (m, 0.4H), 3.43 (m, 0.4H), 3.18 (m, 0.8H), 2.88 (m, 0.8H), 2.56 (m, 1.2H), 2.38 (m, 2.4H); Anal. calcd for C 13 H 15 N 5 .0.5CH 3 CO 2 CH 2 CH 3 : C, 63.14; H, 6.71; N, 24.54. Found: C, 62.75; H, 6.73; N, 24.48. Example 6 6-[1,1'-biphenyl]-2-yl-1,3,5-triazine-2,4-diamine [1,1'-biphenyl]-2-carbonitrile was processed as in Example 1 to provide the title compound. MS (DCI/NH 3 ) m/e 264 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 7.63-7.2 (m, 5H), 7.37-7.27 (m, 4H), 6.6 (br s, 4H); Anal. calcd for C 15 H 13 N 5 : C, 68.42; H, 4.97; N, 26.59. Found: C, 67.85; H, 4.94; N, 26.50. Example 7 6-(4'-nitro[1,1'-biphenyl]-4-yl)-1,3,5-triazine-2,4-diamine 4'-Nitro-[1,1'-biphenyl]-4-carbonitrile was processed as in Example 1 to provide the title compound. mp>250° C.; MS (DCI/NH 3 ) m/e 309 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 8.5-8.4 (m, 4H), 8.1 (d, 2H), 7.95 (d, 2H), 6.85 (br s, 4H); Anal. calcd for C 15 H 12 N 6 O 2 : C, 58.43; H, 3.92; N, 27.42. Found: C, 58.46; H, 3.76; N, 27.12. Example 8 trans-6-[4-(4-pentylcyclohexyl)phenyl]-1,3,5-triazine-2,4-diamine 4-(Trans-4-pentylcyclohexyl)benzonitrile was processed as in Example 1 to provide the title compound. mp>250° C.; MS (DCI/NH 3 ) m/e 340 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 8.2 (d, 2H), 7.3 (d, 2H), 6.75 (bs, 4H), 1.85 (d, 4H), 1.55-1.4 (m, 2H), 1.37-1.2 (m, 10H), 1.1-1.05 (m, 2H), .85 (t, 3H); Anal. calcd for C 20 H 29 N 5 : C, 70.76; H, 8.61; N, 20.62. Found: C, 70.71; H, 8.73; N, 20.67. Example 9 6-(4-phenoxyphenyl)-1,3,5-triazine-2,4-diamine 4-Phenoxybenzonitrile was processed as in Example 1 to provide the title compound. mp 198-200° C.; MS (DCI/NH 3 ) m/e 280 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 8.3-8.2 (m, 2H), 7.5-7.4 (m, 2H), 7.2 (t, 1H), 7.17-7.0 (m, 4H), 6.9-6.65 (br s, 4H); Anal. calcd for C 15 H 13 N 5 O : C, 64.51; H, 4.69; N, 25.07. Found: C, 63.84; H, 4.67; N, 24.90. Example 10 N-cyclohexyl-N'-[4-(4,6-diamino-1,3,5-triazin-2-yl)phenyl]urea Example 10A 4-Aminobenzonitrile was processed as in Example 1 to provide the designated compound. MS (DCI/NH 3 ) m/e 203 (M+H) + . Example 10B N-cyclohexyl-N'-[4-(4,6-diamino-1,3,5-triazin-2-yl)phenyl]urea A mixture of Example 10A (1.0 g; 4.9 mmol), cyclohexylisocyanate (610 mg, 4.9 mmol), and triethylamine (0.68 mL, 4.9 mmol) in dioxane was stirred overnight at room temperature. The precipitate was washed with water and dried under vacuum to provide the title compound. MS (DCI/NH 3 ) m/e 328 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 8.4 (s, 1H), 8.23 (t, 1H), 8.8-8.75 (m, 1H), 7.55-7.45 (m, 1H), 7.25-7.2 (t, 1H), 7.0-6.8 (br s, 4H), 6.0 (d, 1H), 3.55-3.4 (m, 1H), 1.9-1.8 (m, 2H), 1.7-1.6 (m, 2H), 1.59-1.5 (m, 1H), 1.2-0.5 (m, 5H); Anal. calcd for C 15 H 21 N 7 O: C, 58.70; H, 6.47; N, 29.95. Found: C, 58.49; H, 6.59; N, 29.49. Example 11 (4,6-diamino-1,3,5-triazine-2-yl)phenylmethenone 4-Cyanobenzophenone was processed as in Example 1 to provide the title compound. mp>250° C.; 1 H NMR (300 MHz, DMSO-d 6 ) δ 8.4 (d, 2H), 7.9 (d, 2H), 7.8 (m, 2H), 7.7 (m, 1H), 7.6 (t, 2H), 6.9 (br s, 4H); MS (DCI/NH 3 ) m/e 292 (M+H) + ; Anal. calcd for C 16 H 13 N 5 O: C, 65.97; H, 4.50; N, 24.04. Found: C, 65.74; H, 4.32; N, 23.93. Example 12 N-[4-(4,6-diamino-1,3,5-triazin-2-yl)phenyl]-N'-phenyl urea Example 10A was processed as in Example 10B but substituting phenylisocyanate for cyclohexylisocyanate to provide the title compound. 1 H NMR (300 MHz, DMSO-d 6 ) δ 8.8 (s, 1H), 8.65 (s, 1H), 8.35 (t, 1H), 7.9 (d, 1H), 7.6-7.5 (m, 1H), 7.49-7.44 (m, 2H), 7.35 (t, 1H), 7.29 (t, 2H), 7.0 (t, 1H), 6.8-6.7 (br s, 4H); Anal. calcd for C 16 H 15 N 7 O: C, 59.80; H, 4.70; N, 30.51. Found: C, 59.61; H, 4.72; N, 29.91. Example 13 6-(1,4-dioxa-8-azaspiro[4,5]dec-8-yl)-1,3,5-triazine-2,4-diamine A mixture of 2,4-diamino-6-chloro-1,3,5-triazine (2 g, 14 mmol), 1,4-dioxa-8-azaspiro[4.5]decane (3 g, 21 mmol), and KOH (100 mg, 1.8 mmol) in dioxane (10 mL) and ethanol (40 mL) was heated at reflux overnight, diluted with water, and filtered. The precipitate was rinsed with water and dried under vacuum to provide the title compound. mp 209-211° C.; MS (DCI/NH 3 ) m/e 253 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 6.14 (br s, 4H), 3.90 (s, 4H), 3.75-3.68 (m, 4H), 1.58-1.51 (m, 4H); Anal. calcd for C 10 H 16 N 6 O 2 : C, 47.61; H, 6.39; N,33.31. Found: C, 47.45; H, 6.34; N, 33.24. Example 14 6-(4'-pentyl[1,1'-biphenyl]-4-yl)-1,3,5-triazine-2,4-diamine 4'-Pentyl[1,1'-biphenyl]-4-carbonitrile was processed as in Example 1 to provide the title compound. mp 242-244° C.; MS (DCI/NH 3 ) m/e 334 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 8.3 (d, 2H), 8.75 (d, 2H), 8.65 (d, 2H), 7.3 (d, 2H), 6.75-6.82 (br s, 4H), 2.6 (t, 2H), 1.6-1.7 (m, 2H), 1.3-1.4 (m, 4H), 0.95 (t, 3H); Anal. calcd for C 20 H 23 N 5 .0.25H 2 O: C, 71.61; H, 7.09; N, 20.03. Found: C, 71.80; H, 7.00; N, 20.45. Example 15 6-[4'-pentyloxy[1,1'-biphenyl]-4-yl]-1,3,5-triazine-2,4-diamine 4'-(Pentyloxy)[1,1'-biphenyl]-4-carbonitrile was processed as in Example 1 to provide the title compound. mp 246-249° C.; MS (DCI/NH 3 ) m/e 350 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 8.3 (d, 2H), 7.75-7.65 (m, 4H), 7.07 (d, 2H), 6.85-6.7 (br s, 4H), 4.05 (t, 2H), 1.8-1.7 (m, 2H), 1.5-1.3 (m, 4H), 0.9 (t, 3H); Anal. calcd for C 20 H 23 N 5 O: C, 68.75; H ; 6.63; N, 20.04. Found: C, 68.64; H, 6.77; N, 19.94. Example 16 6-(6-methoxy-2-benzothiazolyl)-1,3,5-triazine-2,4-diamine 6-Methoxy-2-benzothiazolecarbonitrile was processed as in Example 1 to provide the title compound. mp>250° C.; MS (DCI/NH 3 ) m/e 275 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 7.98 (d, 1H), 7.71 (d, 1H), 7.17 (dd, 1H), 7.16 (br s, 2H), 6.95 (br s, 2H), 3.85 (s, 3H); Anal. calcd for C 11 H 10 N 6 OS: C, 48.17; H, 3.67; N, 30.64. Found: C, 48.07; H, 3.75; N, 30.72. Example 17 6-(4'-amino[1,1'-biphenyl]-4-yl)-1,3,5-triazine-2,4-diamine 4'-Amino[1,1'-biphenyl]-4-carbonitrile was processed as in Example 1 to provide the title compound. mp>250° C.; MS (DCI/NH 3 ) m/e 279 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 8.25 (d, 2H), 7.65 (d, 2H), 7.45 (d, 2H), 6.8-6.6 (m, 6H), 5.3 (s, 2H); Anal. calcd for C 15 H 14 N 6 : C, 64.73; H, 5.07; N, 30.20. Found: C, 64.34; H, 5.18; N, 29.91. Example 18 6-[4-(5-oxazolyl)phenyl]-1,3,5-triazine-2,4-diamine 4-(5-Oxazolyl)benzonitrile was processed as in Example 1 to provide the title compound. MS (DCI/NH 3 ) m/e 255 (M+H) + ; 1H NMR (300 MHz, DMSO-d 6 ) δ 8.55 (s, 1H), 8.37 (d, 2H), 7.9-7.8 (t, 3H), 6.9-6.7 (br s, 4H); Anal. calcd for C 12 H 10 N 6 O: C, 56.69; H, 3.96; N, 33.05. Found: C, 56.40; H, 4.02; N, 33.11. Example 19 6-[4-[[5-(trifluoromethyl)-2-pyridinyl]oxylphenyl]-1,3,5-triazine-2,4-diamine 4-[[5-(Trifluoromethyl)-2-pyridinyl]oxy]benzonitrile was processed as in Example 1 to provide the title compound. MS (DCI/NH 3 ) m/e 349 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 8.6 (s, 1H), 8.6-8.5 (m, 3H), 7.4-7.3 (m, 3H), 6.9-6.7 (br s, 4H); Anal. calcd for C 15 H 11 F 3 N 6 O: C, 51.73; H, 3.18; N, 24.13. Found: C, 51.67; H, 3.20; N, 23.83. Example 20 4'-(4,6-diamino-1,3,5-triazine-2-yl)[1,1'-biphenyl]-4-carbonitrile Example 20A 4-Bromobenzonitrile was processed as in Example 1 to provide the designated compound. MS (DCI/NH 3 ) m/e 267 (M+H) + . Example 20B A solution of Example 20A (0.76 g, 2.9 mmol) and tetrakis(triphenylphosphine) palladium (0.17 g, 0.15 mmol) in dry, degassed dimethylacetamide (45 mL) was heated to 100° C., treated with hexamethylditin (1.0 g, 3.1 mmol), heated at 100° C. for 3 hours, treated with ethyl acetate, washed sequentially with 1 M NaOH and brine, dried (MgSO 4 ), and concentrated to provide the designated compound. MS (DCI/NH 3 ) m/e 352 (M+H) + . Example 20C 4'-(4,6-diamino-1,3,5-triazine-2-yl)[1,1'-biphenyl]-4-carbonitrile A solution of Example 20B (0.95 g, 2.7 mmol), 4-bromobenzonitrile (0.55 g, 3.0 mmol) and tetrakis(triphenylphosphine) palladium (0.20 g, 0.17 mmol) in dry, degassed dimethylacetamide (45 mL) was heated at 100° C. for 3 hours, cooled to room temperature, treated with ethyl acetate, washed sequentially with 1 M NaOH and brine, dried (MgSO 4 ), and concentrated. The residue was recrystallized from dioxane/ethanol to provide the title compound. mp>260° C.; MS (DCI/NH 3 ) m/e 289 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 8.36 (d, 2H), 7.96 (s, 4H), 7.88 (d, 2H), 6.81 (br s, 4H); Anal. calcd for C 16 H 12 N 6 .0.75H 2 O: C, 63.67; H, 4.51; N, 27.84. Found: C, 64.06; H, 4.38; N, 27.17. Example 21 6-(4'-methoxy[1,1'-biphenyl]-4-yl)-1,3,5-triazine-2,4-diamine A solution of Example 20A (0.749 g, 2.8 mmol) and tetrakis(triphenylphosphine) palladium (0.15 g, 0.13 mmol) in dry, degassed dimethylacetamide (45 mL) was heated to 100° C., treated sequentially with 4-methoxyphenyl boronic acid (0.648 g, 4.3 mmol) in absolute ethanol (15 mL) and saturated NaHCO 3 (30 mL), heated at 100° C. for 3 hours, cooled to room temperature, treated with ethyl acetate, washed with brine, dried (MgSO 4 ), and concentrated. The residue was recrystallized from dioxane/ethanol to provide the title compound. mp>260° C.; MS (DCI/NH 3 ) m/e 294 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 8.31 (d, 2H), 7.72 (t, 4H), 7.03 (d, 2H), 6.86 (br s, 4H), 3.81 (s, 3H); Anal. calcd for C 16 H 15 N 5 O.0.33H 2 O: C, 64.21; H, 5.27; N, 23.40. Found: C, 64.26; H, 5.35; N, 23.43. Example 22 6-(4'-fluoro[1,1'-biphenyl]-4-yl)-1,3,5-triazine-2,4-diamine Example 20A and 4-fluorophenyl boronic acid were processed as in Example 24 to provide the title compound. mp>260° C.; MS (DCI/NH 3 ) m/e 282 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 8.32 (d, 2H), 7.77 (m, 4H), 7.32 (t, 2H), 6.75 (br s, 4H); Anal. calcd for C 15 H 12 FN 5 .0.25H 2 ): C, 63.04; H, 4.41; N, 24.50. Found: C, 63.41; H, 4.49; N, 24.17. Example 23 N-[4-(4,6-diamino-1,3,5-triazin-2-yl)phenyl]benzenesulfonamide A solution of Example 10A, (575 mg, 2.8 mmol) and benzenesulfonyl chloride (554 mg, 3.1 mmol) in pyridine (5 mL) was heated at reflux for 4 hours, stirred overnight at room temperature, treated with water and extracted with ethyl acetate. The extract was washed with water and brine, dried (MgSO 4 ), and concentrated. The residue was recrystallized from ethanol to provide the title compound. mp 197-199° C.; MS (DCI/NH 3 ) m/e 343 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 10.20 (br s, 1H), 8.03-8.01 (m, 1H), 7.94-7.91 (m, 1H), 7.80-7.78 (m, 2H), 7.60-7.50 (m, 3H), 7.34-7.25 (m, 1H), 7.22-7.19 (m, 1H); Anal. calcd for C 15 H 14 N 6 O 2 S.C 2 H 5 OH: C, 52.56; H, 5.18; N, 21.63. Found: C, 52,47; H, 5.24; N, 21.54. Example 24 6-[1-([1,1'-biphenyl]-4-yl)-4-pipzeridinyl]-1,3,5-triazine-2,4-diamine Example 24A A mixture of 4-bromobiphenyl (19.16 g, 82 mmol) in THF (820 mL) at -78° C. was treated with tert-butyl]ithium (100 mL of a 1.7 M solution in pentane, 170 mmol), stirred for 8 minutes, treated with bismuth trichloride (8.62 g, 27.4 mmol) in THF (100 mL), stirred an additional 3 hours, treated with saturated aqueous NH 4 Cl, and extracted with ethyl acetate. The extract was washed with water and brine, dried over (MgSO 4 ) and concentrated. The residue was dried in a vacuum oven to provide the designated compound. 13 CNMR (300 MHz, CDCl 3 ) δ 153.83, 141.04, 140.69, 138.07, 129.21, 128.75, 127.33, 127.07. Example 24B 6-[1-([1,1'-biphenyl]-4-yl)-4-piperidinyl]-1,3,5-triazine-2,4-diamine Example 24A and ethyl isonipecotate were processed as in Examples 2A and 2C to provide the title compound. mp>260° C.; MS (DCI/NH 3 ) m/e 347 (M+H) + ; 1H NMR (300 MHz, DMSO-d 6 ) δ 7.58 (m, 2H), 7.47 (d, 2H), 7.39 (m, 2H), 7.23 (m, 1H), 6.97 (d, 2H), 6.59 (br s, 4H), 3.61 (m, 1H), 1.78 (m, 4H), 1.58 (m, 4H). Example 25 N-[4-(4,6-diamino-1,3,5-triazin-2-yl)phenyl]-2-naphthalenesulfonamide 6-(4-Aminophenyl)-1,3,5-triazine-2, 4diamine was processed as in Example 23 but substituting 2-naphthalenesulfonyl chloride for benzenesulfonyl chloride to provide the title compound. mp 230-233° C.; MS (DCI/NH 3 ) m/e 393 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 10.55 (s, 1H), 8.5 (s, 1H), 8.2-8.05 (m, 3H), 8.0 (d, 1H), 7.9-7.85 (m, 1H), 7.8-7.75 (m, 1H), 7.74-7.6 (m, 2H), 7.3-7.2 (m, 2H), 6.9-6.65 (br s, 4H); Anal. calcd for C 19 H 16 N 6 O 2 S.1.5 C 4 H 8 O 2 : C, 57.23; H, 5.37; N, 16.02. Found: C, 57.11; H, 5.33; N, 16.28. Example 26 2,5-dichloro-N-[4-(4,6-diamino-1,3,5-triazin-2-yl)phenyl]benzenesulfonamide Example 10A was processed as in Example 23 but substituting 2,5-dichlorobenzenesulfonyl chloride for benzenesulfonyl chloride to provide the title compound. mp 230-233° C.; MS (DCI/NH 3 ) m/e 411 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 10.5 (s, 1H), 8.05 (m, 3H), 7.75-7.7 (m, 2H), 7.35 (t, 1H), 7.25-7.2 (m, 1H), 6.8-6.7 (br s, 4H); Anal. calcd for C 15 H 12 C 12 N 6 O 2 S.0.5CH 3 CH 2 OH C, 44.24; H, 3.48; N, 19.35. Found: C, 44.43; H, 3.26; N, 19.44. Example 27 6-(1-phenylcyclohexyl)-1,3,5-triazine-2,4-diamine 1-Phenylcyclohexanecarbonitrile was processed as in Example 1 to provide the title compound. mp 153-155° C.; MS (DCI/NH 3 ) m/e 270 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 7.4-7.3 (m, 2H), 7.15 (t, 2H), 7.2-7.1 (m, 1H), 6.6-6.5 (br s, 4H), 2.7-2.6 (m, 2H), 1.75-1.6 (m, 2H), 1.6-1.2 (m, 6H); Anal. calcd for C 15 H 19 N 5 : C, 66.89; H, 7.11; N, 26.00. Found: C, 66.94; H, 7.20; N, 26.04. Example 28 6-[1-(4-methoxyphenyl)-4-piperidinyl]-1,3,5-triazine-2,4-diamine Tris(4'-methoxy[1,1'-biphenyl]bismuth, prepared as in Example 24A, and ethyl isonipecotate were processed as in Examples 2A and 2C to provide the title compound. mp 204-205° C.; MS (DCI/NH 3 ) m/e 301 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 6.92 (d, 2H), 6.81 (d, 2H), 6.58 (m, 4H), 3.59 (m, 2H), 2.62 (m, 2H), 2.35 (m; 1H), 1.82 (m, 4H). Example 29 6-[2-[4-(trifluoromethyl)phenyl]-4-thiazolyl]-1,3,5-triazine-2,4-diamine Ethyl 2-[4-(trifluoromethyl)phenyl]thiazole-4-carboxylate and Example 2B were processed as in Example 2C to provide the title compound. mp>260° C.; MS (DCI/NH 3 ) m/e 339 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 8.42 (s, 1H), 8.19 (d, 2H), 7.91 (d, 2H), 6.82 (brs, 4H); Anal. calcd for C 13 H 9 F 3 N 6 S: C, 46.15; H, 2.68; N, 24.84. Found: C, 45.85; H, 2.64; N, 24.44. Example 30 6-[1-(4-methoxyphenyl)cyclohexyl]-1,3,5-triazine-2,4-diamine 1-(4-Methoxyphenyl)cyclohexanecarbonitrile was processed as in Example 1 to provide the title compound. mp 159-163° C.; MS (DCI/NH 3 ) m/e 300 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 7.15 (d, 2H), 6.8 (d, 2H), 6.6 (br s, 4H), 3.7 (s, 3H), 2.7-2.6 (m, 2H), 1.7-1.6 (m, 2H), 1.6-1.2 (m, 6H); Anal. calcd for C 16 H 21 N 5 O: C, 64.19; H, 7.07; N, 23.39. Found: C, 64.13; H, 7.07; N, 23.25. Example 31 6-[4-(2-thienyl)phenyl]1,3,5-triazine-2,4-diamine A solution of Example 20A (500 mg, 1.9 mmol) and 2-tri-n-butyltinthiophene (840 mg, 2.2 mmol) in dry, degassed dimethylacetamide (15 mL) was treated with tetrakis(triphenylphosphine) palladium (115 mg, 0.1 mmol), heated at 100° C. for 3 hours, cooled, treated with 1 N NaOH, and extracted with ethyl acetate. The extract was washed with brine, dried (MgSO 4 ), and concentrated. The residue was recrystallized from ethanol /dioxane to provide the title compound. mp>260; MS (DCI/NH 3 ) m/e 270 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 8.31-8.24 (m, 2H), 7.8-7.72 (m, 2H), 7.62-7.59 (m, 2H), 7.2-7.16 (m, 1H), 6.92 (br s, 4H); Anal. calcd for C 13 H 11 N 5 S: C,57.97; H, 4.11; N,26.00. Found: C, 57.91; H, 4.06; N, 25.83. Example 32 6-[4-(phenylethynyl)phenyl]-1,3,5-triazine-2,4-diamine Example 32A 4-Bromobenzonitrile and trimethyl(phenylethynyl)tin were processed as in Example 31 to provide the designated compound. MS (DCI/NH 3 ) m/e 221 (M+NH 4 ) + . Example 32B 6-[4-(phenylethynyl) phenyl]-1,3,5-triazine-2,4-diamine 4-(Phenylethynyl)benzonitrile was processed as in Example 1 to provide the title compound. mp 248-249° C.; MS (DCI/NH 3 ) m/e 289 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 8.30 (d, 2H), 7.67 (d, 2H), 7.61-7.58 (m, 2H), 7.5-7.43 (m, 3H), 6.82 (br s, 4H); Anal. calcd for C 17 H 13 N 5 : C, 71.06; H, 4.56; N, 24.37. Found: C, 70.79; H, 4.73; N, 4.08. Example 33 N,N'-(1,1-biphenyl-4-yl-1,3,5-triazin-2,4-diyl)bis[acetamide] Example 33A 4-Phenylbenzonitrile was processed as in Example 1 to provide the designated compound. MS (DCI/NH 3 ) m/e 264 (M+H) + . Example 33B N,N'-(6-[1,1'-biphenyl]-4-yl-1,3,5-triazin-2,4-diyl)bis[acetamide] A solution of Example 33A (0.26g, 0.99 mmol) in acetic anhydride (10 mL) was refluxed for 20 hours and cooled to room temperature. The precipitate was rinsed with saturated NaHCO 3 , and dried under vacuum to provide the title compound. mp>260° C.; MS (DCNH 3 ) m/e 348 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 10.79 (s, 2H), 8.43 (d, 2H), 7.91 (d, 2H), 7.79 (d, 2H), 7.52 (m, 2H), 7.41 (m, 1H), 2,41 (s, 6H); Anal. calcd for C 19 H 17 N 5 O 2 : C, 65.70; H, 4.93; N, 20.16. Found: C, 65.63; H, 4.84; N, 20.18. Example 34 N-(4-amino-6-[1,1'-biphenyl]-4-yl-1,3,5-triazin-2-yl)acetamide A solution of Example 33A (0.38g, 1.4 mmol) in acetic anhydride (4 mL) was heated at 80° C. for 20 hours, treated with ethyl acetate and cooled to room temperature. The precipitate was collected by vacuum filtration, rinsed with aqueous sodium carbonate, and dried under vacuum to yield the title compound. mp>260° C.; MS (DCI/NH 3 ) m/e 306 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 10.22 (s, 1H), 8.39 (d, 2H), 7.83 (d, 2H), 7.77 (d, 2H), 7.53 (m, 3H), 7.41 (m, 2H), 2.36 (s, 3H); Anal. calcd for C 17 H 15 N 5 O.0.2CH 3 CO 2 H: C, 65.86; H, 5.02; N, 22.07. Found: C, 65.82; H, 4.97; N, 22.37. Example 35 N-[4-(4,6-diamino-1,3,5-triazin-2-yl)phenyl]-1-naphthalenesulfonamide Example 10A was processed as in Example 23 but substituting 1-naphthalenesulfonyl chloride for benzenesulfonyl chloride to provide the title compound. mp>250° C.; MS (DCI/NH 3 ) m/e 393 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 10.8 (s, 1H), 8.8 (d, 1H), 8.3 (d, 1H), 8.2 (d, 1H), 8.1 (d, 1H), 8.0 (s, 1H), 7.83-7.6 (m, 4H), 7.2 (t, 1H), 7.15-7.1 (m, 1H), 6.83-6.7 (m, 4H); Anal. calcd for C 19 H 16 N 6 O 2 S.H 2 O: C, 55.59; H, 4.42; N, 20.47. Found: C, 55.57; H, 4.42; N, 20.52. Example 36 6-(4'-azido[1,1'-biphenyl]-4-yl)-1 .3.5-triazine-2,4-diamine Example 36A A solution of 4'-amino[1,1'-biphenyl]-4-carbonitrile (0.490 g, 2.53 mmol) in trifluoroacetic acid (12.5 mL) was treated sequentially with sodium nitrite (0.338 g, 4.90 mmol) and sodium azide (0.33 g, 5.1 mmol), stirred at room temperature for 10 minutes, treated with water and extracted with ethyl acetate. The extract was dried (MgSO 4 ), concentrated to provide the designated compound. MS (DCI/NH 3 ) m/e 238 (M+NH 4 ) + . Example 36B 6-(4-azido-[1,1'-biphenyl]-4-yl)-1,3,5-triazine-2,4-diamine Example 36A was processed as in Example 1 to provide the title compound. mp 230° C. (decomposes); MS (DCI/NH 3 ) m/e 305 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 8.32 (d, 2H), 7.79 (m, 4H), 7.24 (d, 2H), 6.74 (bds, 4H); Anal. calcd for C 15 H 12 N 8 .0.33H 2 O: C, 58.07; H, 4.11; N, 36.12. Found: C, 58.15; H, 25 3.84; N, 33.09. Example 37 6-[4-(4-morpholinylsulfonyl)phenyl]-1,3,5-triazine-2,4-diamine Example 37A A solution of 4-cyanobenzenesulfonyl chloride (600 mg, 2.98 mmol), morpholine (300 mg, 3.44 mmol), and pyridine (350 μL, 342 mg, 4.33 mmol) in dichloromethane (10 ml) was stirred overnight at room temperature, treated with saturated NH 4 Cl and extracted with ethyl acetate. The extract was washed with water and brine, dried (MgSO 4 ) and concentrated to provide the designated compound. MS (DCI/NH 3 ) m/e 270 (M+NH 4 ) + . Example 37B 4-(2,4-diamino-1,3,5-triazin-2-yl)-N-(4-morpholinyl)benzenesulfonamide Example 37A was processed as in Example 1 to provide the title compound. mp>260° C.; MS (DCI/NH 3 ) m/e 337 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 8.46 (d, 2H), 7.83 (d, 2H), 6.91 (br s, 4H), 3.65-3.60 (m, 4H), 2.94-2.88 (m, 4H); Anal. calcd for C 13 H 16 N 6 O 3 S: C, 46.42; H, 4.79; N, 24.98. Found: C, 46.21; H, 4.69; N, 25.24. Example 38 6-[4(2-furanyl)phenyl]-1,3,5-triazine-2,4-diamine 6-(4-Bromophenyl)-1,3,5-triazine-2,4-diamine was processed as in Example 31 but substituting 2-tri-n-butyltinfuran for 2-tri-n-butyltinthiophene to provide the title compound. MS (DCI/NH 3 ) m/e 254 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 8.3 (d, 2H), 7.8 (d, 3H), 7.05 (d, 1H), 6.8-6.7 (br s, 4H), 6.65-6.6 (m, 1H); Anal. calcd for C 13 H 11 N 5 O: C, 60.30; H, 5.57; N, 24.30. Found: C, 59.83; H, 5.44; N, 24.86. Example 39 N,N'-[6-(4-phenoxyphenyl)-1,3,5-triazine-2,4-diyl]bis[racetamide] Example 9 was processed as in Example 33B to provide the title compound. mp 243-245° C.; MS (DCI/NH 3 ) m/e 364 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 10.74 (s, 2H), 8.38 (d, 2H), 7.47 (t, 2H), 7.24 (t, 1H), 7.14 (dd, 4H), 2.38 (s, 6H); Anal. calcd for C 19 H 17 N 5 O 3 : C, 62.80; H, 4.72; N, 19.27. Found: C, 62.56; H, 4.82; N, 19.40. Example 40 N-[4-amino-6-(4-phenoxyphenyl)-1,3,5-triazin-2-yl]acetamide Example 9 was processed as in Example 34 to provide the title compound. mp>260° C.; MS (DCI/NH 3 ) m/e 322 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 10.21 (s, 1H), 8.32 (d, 2H), 7.46 (t, 2H), 7.37 (bds, 2H), 7.13 (d, 2H), 7.08 (d, 2H), 2.32 (s, 3H); Anal. calcd for C 17 H 15 N 5 O 2 : C, 63.54; H, 4.71; N, 21.79. Found: C, 63.25; H, 4.79; N, 21.84. Example 41 6-(5-phenyl-2-furanyl)-1,3,5-triazine-2,4-diamine Example 41 A Methyl 5-bromo-2-furoate, phenylboronic acid, and tetrakis(triphenylphosphine) palladium were processed as in Example 21 to provide the designated compound. MS (DCI/NH 3 ) m/e 203 (M+H) + . Example 41B 6- (5-phenyl-2-furanyl)-1,3,5-triazine-2,4-diamine Examples 41A and 2B were processed as in Example 2C to provide the title compound. mp>260° C.; MS (DCI/NH 3 ) m/e 254 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 7.80 (d, 2H), 7.52-7.44 (m, 2H), 7.41-7.37 (m, 1H), 7.23 (dd, 1H), 7.16 (dd, 1H), 6.78 (br s, 4H); Anal. calcd for C 13 H 11 N 5 O: C, 61.65; H, 4.37; N, 27.65. Found: C, 61.33; H, 4.37; N, 27.42. Example 42 6-(5-phenyl-2-thienyl)-1,3,5-triazine-2,4-diamine Methyl 5-phenylthiophene-2-carboxylate was processed as in Examples 41A and 41B to provide the title compound. mp>250° C.; MS (DCI/NH 3 ) m/e 270 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 7.80 (d, 1 H), 7.71-7.76 (m, 2H), 7.56 (d, 1H), 7.31-7.49 (m, 3H), 6.78 (bds, 4H); Anal. calcd for C 13 H 11 N 5 S.0.5H 2 O: C, 56.09; H, 4.34; N, 25.16. Found: C, 56.35; H. 4.01; N, 25.27. Example 43 N,N'-[6-(4-phenylcyclohexyl)-1,3,5-triazin-2,4-diyl]bis[acetamide] Example 3 was processed as in Example 33B to provide the title compound. mp 235-236° C.; MS (DCI/NH 3 ) m/e 354 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 10.61 (s, 2H), 7.30 (m, 4H), 7.18 (m, 1H), 2.63 (m, 1H), 2.56 (m, 1H), 2.36 (s, 6H), 1.98 (m, 4H), 1.63 (m, 4H); Anal. calcd for C 19 H 23 N 5 O 2 .0.25H 2 O: C, 63.76; H, 6.62; N, 19.57. Found: C, 63.83; H, 6.52; N, 19.27. Example 44 N-[4-amino-6-(4-phenylcyclohexyl)-l .3.5-triazin-2-yl]acetamide Example 3 was processed as in Example 34 to provide the title compound. mp>260° C.; MS (DCI/NH 3 ) m/e 312 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 10.02 (s, 1H), 7.28 (m, 7H), 2.54 (m, 1H), 2,44 (m, 1H), 2.25 (s, 3H), 1.96 (m, 4H), 1.59 (m, 4H); Anal. calcd for C 17 H 21 N 5 O: C, 65.57; H, 6.80; N, 22,49. Found: C, 65.37; H, 6.85; N, 22.74. Example 45 6-(4-phenyl-1-naphthalenyl)-1,3,5-triazine-2,4-diamine Example 45A A solution of 4-methoxy-1-naphthalenecarbonitrile (3.5 g, 19 mmol) in dichloromethane (15 mL) at -78° C. was treated with BBr 3 (5 g, 20 mmol) in dichloromethane (15 mL), stirred at room temperature for 18 hours, treated with AlCl 3 (5 g, 38 mmol), stirred at room temperature for 18 hours, treated with water and extracted with ethyl acetate. The extract was washed with water and brine, dried (MgSO 4 ), and concentrated. The residue was purified by flash chromatography on silica gel with 30% ethyl acetatelhexane to provide the designated compound. MS (DCI/NH 3 ) m/e 187 (M+NH 4 ) + . Example 45B A solution of Example 45A (1.0 g, 5.9 mmol), triethylamine (1 mL, 7.2 mmol) and N-phenyl-tri fluoromethanesulfonamide (2.1 g, 5.9 mmol) in dichloromethane (15 mL) at 0° C. was stirred overnight at room temperature. The reaction was treated with ethyl acetate and washed sequentially with 10% HCl, 20% KOH, water, and brine, dried (MgSO 4 ), and concentrated to provide the designated compound. MS (DCI/NH 3 ) m/e 319 (M+NH 4 ) + . Example 45C Example 45B and phenylboronic acid were processed as in Example 21 to provide the designated compound. MS (DCI/NH 3 ) m/e 247 (M+NH 4 ) + . Example 45D 6-(4-Phenyl-1-napthalenyl)-1,3,5-triazine-2,4-diamine Example 45C was processed as in Example 1 to provide the title compound. mp 239-240° C.; MS (DCI/NH 3 ) m/e 314 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 8.84-8.80 (m, 1H), 7.97 (d, 1H), 7.85-7.81 (m, 1H), 7.69-7.48 (m, 8H), 6.84 (bds, 4H); Anal. calcd for C 19 H 15 N 5 : C, 72.82; H, 4.82; N, 22.34. Found: C, 72.68; H, 4.77; N, 22.35. Example 46 6-[4-(phenylthio)phenyl]-1,3,5-triazine-2,4-diamine Example 46A A solution of 4-bromobenzonitrile (1.0 g, 5.5 mmol), thiophenol (644 mg, 5.8 mmol), K 2 CO 3 (1.9 g, 13.7 mmol) and CuI (1.05 g, 5.5 mmol) in DMF (20 mL) was heated at reflux for 24 hours, treated with ethyl acetate and filtered through Celite®. The filtrate was washed with water and brine, dried (MgSO 4 ), and concentrated. The residue was purified by flash chromatography on silica gel with 5% ethyl acetate/hexane to provide the designated compound. MS (DCI/NH 3 ) m/e 229 (M+NH 4 ) + . Example 46B 6-[4-(phenylthio)phenyl]-1,3,5-triazine-2,4-diamine Example 46A was processed as in Example 1 to provide the title compound. mp 213-215° C.; MS (DCI/NH 3 ) m/e 296 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 8.19 (d, 2H), 7.44-7.41 (m, 5H), 7.32 (d, 2H), 6.77 (bds, 4H); Anal. calcd for C 15 H 13 N 5 S: C, 60.99; H, 4.43; N, 23.71. Found: C, 60.70; H, 4.32; N, 23.55. Example 47 6-(2-quinolinyl)-1,3,5-triazine-2,4-diamine 2-Quinolinecarbonitrile was processed as in Example 1 to provide the title compound. MS (DCI/NH 3 ) m/e 239 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 8.5 (d, 1H), 8.35 (d, 1H),. 8.15-8.0 (m, 2H), 7.9-7.8 (m, 1H), 7.75-7.7 (m, 1H), 7.1-7.0 (br s,,2H), 7.0-6.9 (br s, 2H); Anal. calcd for C 12 H 10 N 6 : C, 60.49; H, 4.23; N, 35.27. Found: C, 60.24; H, 3.94; N, 35.12. Example 48 6-(3-quinolinyl)-1,3,5-ttiazine-2,4-diamine 3-Quinolinecarbonitrile was processed as in Example 1 to provide the title compound. mp>250° C.; MS (DCI/NH 3 ) m/e 239 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 9.7 (d, 1H), 9.1 (d, 1H), 8.2-8.1 (m, 2H), 6.9-6.85 (m, 1H), 6.8-6.7 (m, 1H), 7.05-6.9 (br s, 4H); Anal. calcd for C 12 H 10 N 6 : C, 60.49; H, 4.23; N, 35.27. Found: C, 60.32; H, 4.06; N, 35.54. Example 49 6-(benzorbl thien-2-ylmethyl)-1,3,5-triazine-2,4-diamine Benzo[b]thiophene-2-acetonitrile was processed as in Example 1 to provide the title compound. mp 216-218° C.; MS (DCI/NH 3 ) m/e 258 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 7.97-7.92 (m, 1H), 7.87-7.80 (m, 1H), 7.48 (s, 1H), 7.4-7.32 (m, 2H), 6.65 (br s, 4H), 3.90 (s, 2H); Anal. calcd for C 12 H 11 N 5 S: C, 56.01; H, 4.30; N, 27.21. Found: C, 55.97; H, 4.19; N, 27.31. Example 50 6-(2.2-dimethyl-2H-1-benzop yran-6-yl)-1,3,5-triazine-2,4-diamine 2,2-Dimethyl-2H-1-benzopyran-6-carbonitrile was processed as in Example 1 to provide the title compound. MS (DCI/NH 3 ) m re 270 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 8.05 (dd, 1H), 7.95 (d, 1H), 6.9 (d, 1H), 6.78-6.75 (br s, 4H), 6.70 (d, 1H), 5.80 (d, 1H), 1.20 (s, 6H); Anal. calcd for C 14 H 15 N 5 O: C, 62,44; H, 5.61; N, 26.00. Found: C, 62.19; H, 5.70; N, 25.54. Example 51 6-(2,3-dihydro-1,4benzodioxin-2-yl)-1,3,5-triazine-2. 4diamine 2,3-Dihydro-1,4-benzodioxine-2-carbonitrile was processed as in Example 1 to provide the title compound. MS (DCI/NH 3 ) m/e 246 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 7.0-6.75 (m, 8H), 3.5 (t, 1H), 3.3 (d, 2H); Anal. calcd for C 11 H 11 N 5 O 2 : C, 53.81; H, 4.52; N, 28.55. Found: C, 53.80; H, 4.36; N, 28.40. Example 52 6-(tricyclo[3.3.1.1 3 .7 ]decan-1-yl)-1,3,5-triazine-2,4-diamine Methyl tricyclo[3.3.1,1 3 .7)decane-1-carboxylate and Example 2B were processed as in Example 2C to provide the title compound. mp 261-262° C.; MS (DCI/NH 3 ) m/e 246 (M+H) + ; 1H NMR (300 MHz, DMSO-d 6 ) δ 6.47 (br s, 4H), 2.05-1.95 (m, 3H), 1.9-1.88 (m, 6H), 1.77-1.60 (m, 6H); Anal. calcd for C 13 H 19 N 5 : C, 63.64; H, 7.80; N, 28.54. Found: C, 63.48; H, 7.66; N, 28.34. Example 53 6-(1-isoquinolinyl)-1,3,5-triazine-2,4-diamine 1-Isoquinolinecarbonitrile was processed as in Example 1 to provide the title compound. mp>250° C.; MS (DCI/NH 3 ) m/e 239 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 8.7 (d, 1H), 8.2 (d, 1H), 8-0 (d, 1H), 7.9 (d, 1H), 7.8 (dt, 1H), 7.65 (dt, 1H), 6.9 (bs, 4H); Anal. calcd for C 12 H 10 N 6 .0.3H 2 O: C, 60.49; H, 4.23; N, 35.27. Found: C, 59.55; H, 4.35; N, 34.03. Example 54 (+/-)-4-(4,6-diamino-1,3,5-triazine-2-yl)-a-phenylbenzenemethanol A mixture of Example 11 (150 mg, 0.515 mmol) and sodium borohydride (6 mg, 0.15 mmol) in ethanol (5 mL) was heated at reflux for 30 minutes then stirred overnight at room temperature. The precipitate was rinsed with water and dried under vacuum to provide the title compound. mp 214-216° C.; MS (DCI/NH 3 ) m/e 294 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 8.2 (d, 2H), 7.5 (d, 2H), 7.4 (d, 2H), 7.3 (t, 2H), 7.2 (m, 1H), 6.7 (br s, 4H), 6.0 (d, 1H), 5.75 (d, 1H); Anal. calcd for C 16 H 15 N 5 O: C, 65.51; H, 5.15; N, 23.87. Found: C, 65.33; H, 4.91; N, 23.65. Example 55 6-(2,3-dihydro-1,4-benzodioxin-6-yl)-1,3,5-triazine-2,4-diamine 2,3-Dihydro-1,4-benzodioxine-6-carbonitrile was processed as in Example 1 to provide the title compound. mp 241-244° C.; MS (DCI/NH 3 ) m/e 246 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 8.8-8.75 (m, 2H), 6.95-6.9 (m, 1H), 6.9-6.8 (br s, 4H), 4.25-4.33 (m, 4H); Anal. calcd for C 11 H 11 N 5 O 2 : C, 53.87; H, 4.52; N, 28.56. Found: C, 53.93; H, 4.27; N, 28.41. Example 56 6-(1-azabicyclo[2,2,2]octan-4-yl)-1,3,5-triazine-2,4-diamine 1-Azabicyclo[2,2,2]octane-4-carbonitrile was processed as in Example 1 to provide the title compound. mp>245° C.; MS (DCI/NH 3 ) m/e 221 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 6.6-6.5 (br s, 4H), 3.35 (s, 2H), 2.9 (t, 5H), 1.7 (t, 5H); Anal. calcd for C 10 H 16 N 6 : C, 54.53; H, 7.32; N, 38.15. Found: C, 54.40; H, 7.38; N, 38.25. Example 57 6-[4-(phenylsulfinyl)phenyl]1,3,5-triazine-2,4-diamine A mixture of Example 49 (102 mg, 0.34 mmol) and Oxone® (106 mg, 0.17 mmol) in acetic acid (2 mL) was stirred overnight at ambient temperature, treated with saturated NaHCO 3 and extracted with ethyl acetate. The extract was washed with water and brine, dried (MgSO 4 ), and concentrated. The residue was recrystallized from ethanol to provide the title compound. mp 253-255° C.; MS (DCI/NH 3 ) m/e 312 (M+H) + ; 1 H NMR (300 MHz, DMS (d 6 ) δ 8.36 (d, 2H), 7.81 (d, 2H), 7.75-7.72 (m, 2H), 7.60-7.52 (m, 3H), 6.82 (br s, 4H); Anal. calcd for C 15 H 13 N 5 OS.0.25H 2 O: C, 57.03; H, 4.30; N, 22.17. Found: C, 57.47; H, 4.04; N, 21.81. Example 58 6-[4-(phenylsulfonyl)phenyl]-1,3,5-triazine-2,4-diamine 4-(Phenylsulfonyl)benzonitrile (J. Org. Chem. 1989, 54, 4691) was processed as in Example 1, to provide the title compound. mp>250° C.; MS (DCI/NH 3 ) m/c 328 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 8.41 (d, 2H), 8.08 (d, 2H), 7.96 (d, 2H), 7.71-7.60 (m, 3H), 6.92 (br s, 4H); Anal. calcd for C 15 H 13 N 5 O 2 S.0.25H 2 O: C, 54.28; H, 4.10; N, 21,10. Found: C, 54.28; H, 3.92; N, 20.82. Example 59 E/Z-[4-(4,6-diamino-1,3,5-triazine-2-yl)phenyl]phenylmethanone,oxime A mixture of Example 11 (300 mg, 1.03 mmol) and hydroxylamine hydrochloride (70 mg, 1.0 mmol) in 1:1 ethanol/pyridine (10 mL) was heated at reflux for 3 hours, stirred overnight at room temperature, treated with water, and filtered. The precipitate was rinsed with water and dried to provide the title compound. 35 mp 97-107° C.; MS (DCI/NH 3 ) m/e 307 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 11.42 (s, 0.5H), 11.41 (s, 0.5H), 8.35 (d, 1H), 8.2 (d, 1H), 7.3-7.5 (m, 7H), 6.8 (br s, 4H); Anal. calcd for C 16 H 14 N 6 O.CH 3 CH 2 OH: C, 61.35; H, 5.72; N, 23.84. Found: C, 61.67; H, 5.29; N, 23.37. Example 60 6- pyrazinyl-1,3,5-triazine-2,4-diamine Pyrazinecarbonitrile was processed as in Example 1 to provide the title compound. mp>250° C.; MS (DCI/NH 3 ) m/e 190 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 6.9 (br s, 2H), 7.1 (br s, 2H), 8.75-8.8 (m, 2H), 9.3 (s, 1H); Anal. calcd for C 7 H 7 N 7 : C, 44.44; H, 3.72; N, 51.82. Found: C, 44.40; H, 3.62; N, 51.79. Example 61 2,4-diamino-6-[(4-phenylethenyl)phenyl]-1,3,5-triazine Example 61A A solution of benzyltriphenylphosphonium chloride (22.8 g, 58 mmol) in THF (100 mL) at room temperature was treated with lithium hexamethyldisilazide (1 M in toluene, 53 mL, 53 mmol), heated to reflux for 15 minutes, cooled to room temperature, treated with 4-cyanobenzaldehyde (7 g, 53 mmol) in THF (40 mL), stirred overnight at room temperature, acidified with 10% HCl, and filtered. The filtrate was extracted with ethyl acetate, dried (MgSO 4 ), and concentrated. The residue was dissolved in hot ethyl acetate and filtered through a plug of silica gel to provide the designated compound. Example 61B Example 61A was processed as in Example 1 to provide the title compound. mp 216-217° C.; MS (DCI/NH 3 ) m/e 290 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 8.25 (d, 2H), 7.75 (d, 2H), 7.65 (d, 2H), 7.2-7.4 (m, 5H), 6.75 (br s, 4H); Anal. calcd for C 17 H 15 N 5 .0.5CH 3 CO 2 CH 2 CH 3 : C, 68.45; H, 5.74; N, 21.00. Found: C, 68.50; H, 5.49; N, 21.43. Example 62 2,4-diamino-6-[(4-(2-nitrophenyl)ethenyl)phenyl]-1,3,5-triazine 4-Nitrobenzyltriphenylphosphonium bromide was processed as in Examples 61A and 61B t o provide the title compound. mp>250° C.; MS (DCI/NH 3 ) m/e 335 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 8.25 (t, 4H), 7.9 (d, 2H), 7.8 (d, 2H), 7.6 (m, 2H), 6.8 (br s, 4H); Anal. calcd for C 17 H 14 N 6 O 2 : C, 61.07; H, 4.22; N, 25.14. Found: C, 60.78; H, 4.12; N, 24.89. Example 63 6-[1,1'-biphenyl]-4l-N.N'-dimethyl-1,3,5-triazine-2,4-diamine Example 63A 2-[1,1'-biphenyl]-4-yl-4,6-dichloro-1,3,5-triazine A mixture of 4-phenyl-phenyl magnesium bromide (prepared from 4-bromobiphenyl (7.75 g, 33 mmol) and magnesium turnings (0.83 g, 35 mmol) in 40 mL ether) and cyanuric chloride (4.00 g, 21.7 mmol) in benzene (90 mL) was stirred at 0° C. for 90 minutes. The reaction was evaporated to dryness, and the residue was flash chromatographed on silica gel with 50% hexanes/methylene chloride to provide the desired compound (2.80 g, 43%). MS (DCI/NH 3 ) m/e 301 (M+H) + . Example 63B 6-[1,1'-biphenyl]-4-yl-N,N'-dimethyl-1,3,5-triazine-2,4-diamine A mixture of Example 63A (0.52 g, 1.72 mmol) and N-methylamine (30 mmol) in tetrahydrofuran (25 mL) was stirred at ambient temperature for 72 hours. The reaction was reduced in volume and diluted with water. The precipitate was collected, rinsed with water and ether, and dried. Purification by reverse phase HPLC provided the desired compound. mp 198-200° C.; MS (DCI/NH 3 ) m/e 292 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 8.37 (m, 2H), 7.74 (m, 4H), 7.51 (m, 2H), 7.39 (m, 1H), 7.22 (bdm, 2H), 2.82 (m, 6H); Anal. calcd for C 17 H 17 N 5 .0.25 H 2 O: C, 69.01; H, 5.96; N, 23.67. Found: C, 69.37; H, 5.85; N, 23.63. Example 64 6-[1,1'-biphen yl]-4-yl-N-methyl-1,3,5-triazine-2,4-diamine Example 64A 4-[1,1'-biphenyl]4-yl-6-chloro-1,3,5-triazin-2-amine A mixture of 2-[1,1'-biphenyl]-4-yl-4,6-dichloro-1,3,5-triazine (Example 63A) (0.804 g, 2.67 mmol) in 40 mL ether and concentrated ammonium hydroxide (2 mL, 30 mmol) in tetrahydrofuran (30 mL) was stirred at 0° C. for 60 minutes and at ambient temperature for 20 minutes. The reaction was reduced in volume, diluted with water, and the precipitate was collected, rinsed with water and ether, and dried to provide the desired compound (0.090 g, 12%). MS (DCI/NH 3 ) m/e 282 (M+H) + . Example 64B 6-[1,1'-biphenyl]-4-yl-N-methyl-1,3,5-triazine-2,4-diamine Example 64A (0.090 g, 0.32 mmol) and N-methylamine (6 mmol) in tetrahydrofuran (9 mL) was stirred at ambient temperature for 24 hours. The reaction was reduced in volume and diluted with water. The precipitate was collected, rinsed with water and ether, and dried to provide the desired compound (0.062 g, 70%). mp 237-238° C.; MS (DCI/NH 3 ) m/e 278 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 8.39 (d, 1H), 8.32 (d, 1H), 7.77 (m, 4H), 7.51 (t, 2H), 7.41 (m, 1H), 7.25 (q, 1H), 6.79 (bds, 2H), 2.79 (d, 3H); Anal. calcd for C 16 H 15 N 5 .0.5 C 4 H 8 0 2 : C, 67.27; H, 5.96; N, 21.79. Found: C, 67.20; H, 5.71; N, 22.05. Example 65 6-(bicy glo[2.2.1]hept-2-yl)-1,3,5-triazine-2,4-diamine Example 65A 6-(bicyclo[2.2.1]hept-2-en-5-yl)-1,3,5-triazine-2,4-diamine Bicyclo[2.2. 1]hept-2-ene-5-carbonitrile was processed as in Example 1 to provide the desired compound. MS (DCI/NH 3 ) m/e 204 (M+H) + . Example 65B 6-(bicyclo[2.2.1]hept-2-yl)-1,3,5-triazine-2,4-diamine A solution of Example 65A in methanol was reduced with hydrogen gas and palladium on charcoal, filtered, and evaporated to provide the desired compound. mp 216-217° C.; MS (DCI/NH 3 ) m/e 206 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 6.52 (bds, 4H), 2.83 (m, 1H), 2.39 (m, 1H), 2.21 (m, 1H), 2.04 (m, 1H), 1.91 (m, 1H), 1.6-1.2 (m, 5H), 6.52 (m, 1H); Anal. calcd for C 10 H 15 N 5 : C; 58.52, H; 7.37, N; 34.12. Found: C; 58.59, H; 7.40, N; 34.00. Example 66 6-[1,1'-biphenyl]-4-yl-N,N'-diethyl-1,3,5-triazine-2,4-diamine A mixture of 2,4di-N-ethylamino-6-chloro-1,3,5-triazine (0.55 g, 2.7 mmol) and tetrakis(triphenylphosphine) palladium (0.19 g, 0.16 mmol) in dry, degassed dimethylacetamide (45 mL) was heated to 100° C., treated sequentially with 4-(phenyl)phenyl boronic acid (Yabroff et al., Journal of the American Chemical Society, Volume 56, 1934, pp.1850-1856) (0.80 g, 4.0 mmol) in absolute ethanol (15 mL) and saturated aqueous sodium bicarbonate (30 mL), and the reaction mixture was maintained at 100° C. for 3 days. The reaction mixture was cooled to room temperature and diluted with ethyl acetate. The organic layer was washed with brine, dried (MgSO 4 ), concentrated, and vacuum dried. The residue was recrystallized from 2:1 dioxane/ethanol to provide 0.15 g (17%) of the desired compound as a white solid. mp 183-184° C.; MS (DCI/NH 3 ) m/e 320 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 8.36 (m, 2H), 7.78 (d, 2H), 7.73 (d, 2H), 7.49 (m, 2H), 7.38 (m, 1H), 7.28 (m, 2H), 3.40 (m, 4H), 1,16 (m, 6H); Anal. calcd for C 19 H 21 N 5 .0.2 C 4 H 8 O 2 : C,70.91; H, 6.55; N, 8.28. Found: C,71.21; H, 6.50; N, 21,13. Example 67 6-(2'-nitror[1,1'-biphenyl]-4-yl)-1,3,5-triazine-2,4-diamine 4-Cyano-2'-nitrobiphenyl was processed as in Example 1 to provide the desired compound. mp>250° C.; 1 H NMR (300 MHz, DMSO-d 6 ) δ 8.3 (d, 2H, J=9 Hz), 8-05 (dd, 1H), 7.8 (m, 1H), 7.6-7.7 (m, 2H), 7.45 (d, 2H), 6.8 (br s, 4H); MS (DCI/NH 3 ) m/e 309 (M+H) + ; Anal. calcd for C 15 H 12 N 6 O 2 : C, 58.44; H, 3.92; N, 27.26. Found: C, 58.46; H, 3.99; N, 27.15. Example 68 6-(6-methyl-3-pyridinyl)-1,3,5-triazine-2,4-diamine 6-Methylnicotinonitrile was processed as in Example 1 to provide the desired compound. mp>260° C.; MS (DCI/NH 3 ) m/e 203 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 9.23 (d, 1H), 8.39 (dd, 1H, J=11), 7.38 (d, 1H), 6.81 (br s, 4H), 2.56 (s, 3H); Anal. calcd for C 9 H 10 N 6 : C, 53.45; H, 4.98; N, 41.55. Found: C, 53.46; H, 4.94; N, 41.84. Example 69 6-(6-chloro-3-pvridinyl)-1,3,5-triazine-2,4-diamine Methyl 6-chloronicotinate and imidodicarbonimidic diamide (2B) was processed as in Example 2C to provide the desired compound. mp>260° C.; MS (DCI/NH 3 ) m/e 223, 225 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 9.17 (d, 1H), 8.46 (dd, 1H, J=11), 7.62 (d, 1H), 6.91 (br s, 4H); Anal. calcd for C 8 H 7 ClN 6 : C, 43.15; H, 3.16; N, 37.74. Found: C, 43.05; H, 3.08; N, 37.50. Example 70 6-(5-bromo-3-pyridinyl)-1,3,5-triazine-2,4-diamine 5-Bromonicotinonitrile was processed as in Example 1 to provide the desired compound. mp>260° C.; MS (DCI/NH 3 ) m/e 267 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 9.3 (d, 1H), 8.82 (d, 1H, J=3 Hz), 8.62-8.64 (m, 1H), 6.8-7.1 (br s, 1H); Anal. calcd for C 8 H 7 BrN 6 : C, 35.98; H, 2.64; N, 31.47. Found: C, 35.89; H, 2.53; N, 31.22. Example 71 6-(2,3-dihydro-2,2,3,3-tetrafluoro-1,4-benzodioxin-6-yl)-1,3,5-triazine-2,4-diamine 6-Cyano-2,3-dihydro-2,2,3,3-tetrafluoro-1,4-benzodioxane was processed as in Example 1 to provide the desired compound. mp 176-179° C.; MS (DCI/NH 3 ) m/e 275 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 7.98 (d, 1H), 7.71 (d, 1H), 7.17 (dd, 1H), 7.16 (br s, 2H), 6.95 (br s, 2H), 3.85 (s, 3H); Anal. calcd for C 11 H 7 F 4 N 5 O 2 : C; 41.65, H; 2.22, N; 22.08. Found: C; 41.55, H; 2.10, N; 22.09. Example 72 6-[4-[(4-chlorophenyl)methoxy]phenyl]-1,3,5-triazine-2,4-diamine 4[(4-Chlorophenyl)methoxy]benzonitrile was processed as in Example 1 to provide the desired compound. mp 246-248° C.; MS (DCI/NH 3 ) m/e 342 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 7.45 (s, 4H), 7.25 (d, 2H), 6.9 (d, 2H), 6.6 (br s, 4H), 5.05 (s, 2H), 3.55 (s, 2H); Anal. calcd for C 17 H 16 ClN 5 O: C, 59.74; H, 4.72; N, 20.49. Found: C, 59.64; H, 4.64; N, 20.49. Example 73 6-[4-(1-piperidinylsulfonyl)phenyl]-1,3,5-triazine-2,4-diamine Example 73A 1-[(4-cyanophenyl)sulfonyl]piperidine A mixture of 4-cyanobenzenesulfonyl chloride (0.51 g, 2.5 mmol) and piperidine (0.60 mL, 517 mg, 6.04 mmol) in 10 mL methylene chloride was stirred overnight at ambient temperature. The organic layer was washed successively with water, 5% HCl and brine, dried (Na 2 SO 4 ) and concentrated. The resulting white solid (0.61 g, 96%) was used with no further purification. Example 73B 6-[4-(1-piperidinylsulfon yl)phenyl]-1,3,5-triazine-2,4-diamine The product of Example 73A was processed as in Example 1 to provide the desired compound. m.p.>260° C.; MS (DCI/NH 3 ) m/e 335 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 8.43 (d, 2H), 7.84 (d, 2H), 6.90 (bds, 4H), 2.90-2.97 (m, 4H), 1.50-1.59 (m, 4H), 1.32-1.42 (m, 2H); Anal. calcd for C 14 H 18 N 6 O 2 S: C, 50.28; H, 5.42; N, 25.13. Found: C, 50.43; H, 5.32; N, 5.12. Example 74 6-(1-benzoyl-4-piperidinyl)-1,3,5-triazine-2,4-diamine Example 74A 1-benzoyl-4-piperidinecarbonitrile A mixture of 1-benzoyl-4-piperidone (2.0 g, 9.8 mmol), tosylmethyl isocyanide (2.5 g, 12.8 mmol) and ethanol (1.0 mL, 17.1 mmol) in 30 mL DME was cooled in an ethanol/ice bath, and potassium tert-butoxide was added at such a rate to maintain the reaction temperature at <10° C. The cold bath was removed, and the reaction was allowed to stir overnight at room temperature. The solids were removed by filtration, rinsed with DME, and the filtrate was evaporated. The residue was dissolved in EtOAc, washed with water and brine, dried (MgSO 4 ), filtered through silica gel, and concentrated to give 2.14 g (66%) of a slightly yellow oil. Example 74B 6-(1-benzoyl-4-piperidinyl)-1,3,5-triazine-2,4-diamine The product of Example 74A was processed as in Example 1 to provide the desired compound. m.p. 246-248° C.; MS (DCI/NH 3 ) m/e 299 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 7.43-7.49 (m, 3H), 7.33-7.39 (m, 2H), 6.58 (bds, 4H), 4.44-4.52 (bm, 1H), 3.55-3.67 (bm, 1H), 2.79-3.27 (bm, 2H), 1.53-1.94 (bm, 5H); Anal. calcd for C 15 H 18 N 6 O: C, 60.38; H, 6.08; N, 28.16. Found: C, 60.09; H, 6.02; N, 28.29. Example 75 6-[1-(phenylmethyl)-4-piperidinyl]-1,3,5-triazine-2,4-diamine N-Benzyl-4-piperidone was processed as in example 74A and 74B to provide the desired compound. m.p.>260° C.; MS (DCI/NH 3 ) m/e 285 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) d 7.19-7.32 (m, 5H), 6.50 (bds, 4H), 3.44 (s, 2H), 2.78-2.86 (m, 2H), 2.16-2.28 (m, 1H), 1.90-1.99 (m, 2H), 1.63-1.76 (m, 4H); Anal. calcd for C 15 H 20 N 6 .H 2 O: C, 59.58; H, 7.33; N, 27.79. Found: C, 60.06; H, 7.19; 27.94. Example 76 N,N'-diacetyl-6-[4-(phenylsulfonyl)phenyl]-1,3,5-triazine-2,4-diamine 6-[4-(phenylsulfonyl)phenyl]1,3,5-triazine-2,4-diamine (Example 58) was processed as in Example 33B to provide the desired compound. mp>260° C.; MS (DCI/NH 3 ) m re 412 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 8.52 (d, 2H, J=8 Hz), 8.18 (d, 2H, J=8 Hz), 8.01 (m, 2H), 7.73 (m, 1H), 7.68 (m, 2H), 2.37 (s, 6H); Anal. calcd for C 19 H 17 N 5 O 4 : C, 55.47; H, 4.16; N, 17.02. Found: C, 55.47; H, 4.19; N, 17.11. Example 77 N-acetyl-6-[4-(phenylsulfonyl)phenyl]-1,3,5-triazine-2,4-diamine 6-[4-(phenylsulfonyl)phenyl]1,3,5-triazine-2,4-diamine (Example 58) was processed as in Example 34 to provide the desired compound. mp>260° C.; MS (DCI/NH 3 ) m/e 370 (M+H) + ; 1 H NMR (300 MHz, CF 3 CO 2 D) δ 8.51 (d, 2H), 8.27 (d, 2H), 8.06 (d, 2H), 7.78 (t, 1H), 7.68 (t, 2H), 2.56 (s, 3H); Anal. calcd for C 17 H 15 N 5 O 3 .0.5 H 2 O: C, 53.96; H, 4.26; N, 18.51. Found: C, 53.75; H, 3.91; N, 18.83. Example 78 6-[2-(1-piperidinyl)phenyl)]-1,3,5-triazine-2,4-diamine 2-(1-piperidinyl)benzonitrile was processed as in Example 1 to provide the desired compound. mp>250° C.; MS (DCI/NH 3 ) m/e 271 (M+H) + ; 1 H NMR (300 MHz, DMSO-d 6 ) δ 7.27 (d, 2H), 6.93 (d, 2H), 6.89 (m, 1H), 6.63 (bds, 4H), 3.88 (m, 4H), 1.47 (bdm, 6H); Anal. calcd for C 14 H 18 N 6 : C; 62.20, H; 6.71, N; 31.09. Found: C; 61.88, H; 6.36, N; 31.37.

Compounds having Formula I ##STR1## or pharmaceutically acceptable salts or prodrugs thereof, are useful for treating pathological states which arise from or are exacerbated by angiogenesis. The invention also relates to pharmaceutical compositions comprising these compounds and to methods of inhibiting anglogenesis in a mammal.

RELATED APPLICATION DATA This application claims priority to provisional applications 61/751,787, filed Jan. 11, 2013, and 61/759,996, filed Feb. 1, 2013 FIELD OF TECHNOLOGY The present technology relates to camera systems. BACKGROUND AND INTRODUCTION Foveon, Inc. (now Sigma Corporation) produces image sensors comprising an array of photosites, each of which includes three vertically-stacked photodiodes. Each of the three photosites responds to different wavelengths of light (i.e., each has a different spectral sensitivity curve). The Foveon technology is detailed, e.g., in U.S. Pat. Nos. 6,727,521, 6,731,397, 6,841,816, 6,958,862, 6,998,660, and 7,339,216. Lytro, Pelican Imaging and others produce light field cameras that capture 4D light field information about a scene, through use of microlenses. Such “plenoptic imaging” systems are detailed, e.g., in patent publications 20070252074, 20080131019, 20080266655, 20100026852, 20100265385, 20110069189, 20110080487, and 20110122308. Various companies have developed transparent semiconductors, transistors and electrodes useful in CMOS image sensors. Exemplary technology is detailed in Samsung's patent applications 20110156114 and 20090101948. Familiar transparent electrode materials include tin-doped indium oxide, zinc oxide, and carbon nanotube films. Additional information is provided in Ginsley, et al, Handbook of Transparent Conductors, Springer, 534 pp., 2011. The artisan is presumed to be familiar with technologies involved in fabrication of semiconductor image sensors, including the foregoing. In accordance with one aspect of the present technology, photosensors are again stacked. However, the stacking is considerably thicker than the prior art, making possible camera sensors that provide multi-focal length imaging, e.g., between six inches and infinity. FIG. 1 introduces certain concepts used in the technology. Plural layers P1-P8 are stacked in an integrated structure, behind a lens system. Each layer comprises one or more photodetectors. The distance of each layer behind the lens corresponds to a different object distance, in accordance with the focal length of the lens. (I.e., the reciprocal of the object-lens distance, plus the reciprocal of the photodetector-lens distance, equals the reciprocal of the lens focal length.) An image sensor can comprise a 2D array of such stacks, as illustrated schematically in FIG. 2 . The foregoing and many other features and advantages of the present technology will be apparent from the following detailed description, which proceeds with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a stack comprising plural photodetectors. FIG. 2 shows an array comprising a 2D array of the stacks of FIG. 1 . FIG. 3 shows a basic implementation using two stacked image sensors. FIG. 3A shows an image sharpness curve for the implementation of FIG. 3 . FIG. 4 is similar to FIG. 3 , but shows four stacked image sensors. FIGS. 5-8 show other variants employing stacked image sensors. FIG. 9 shows a sparse color filter array. FIG. 10 illustrates how photosites in different layers of a stack can be at different positions in the layers. FIG. 11A show how the various photosites in the FIG. 10 arrangement may spatially relate, when viewed down through the stack. FIGS. 11B and 11C are similar to FIG. 11A , but illustrate other spatial relations. FIGS. 12A and 12B show different tree structures, by which photosites can be arranged relative to charge-conducting electrodes. FIG. 13 is a diagram illustrating movement of a smartphone sensor as a function of time. FIG. 14 is a schematic illustration of part of a smartphone camera system according employing certain aspects of the present technology. FIGS. 15A and 15B illustrate 2D motion of a smartphone sensor as a function of time. FIGS. 16 and 17 outline the evolution of imaging systems, culminating with “Era 5”—the subject of the present technology. DETAILED DESCRIPTION FIG. 3 shows a first particular embodiment, including first and second stacked image sensors, and a lens system. The first sensor is at an image plane corresponding to an object at an infinite distance from the lens system; the second sensor is at an image plane corresponding to an object at a distance of six inches. The two sensors have the same pixel dimensions (e.g., 1936×2592 pixels). The first sensor is fabricated to pass at least some of the light incident on its top surface through its structure, and on towards the second image sensor. Such transmissivity can be achieved by appropriate design and fabrication of the charge transfer conductors and associated readout circuitry, so that some light passing through the photodetection region is not blocked by such structures. For example, the structures may be sized and placed so that gaps between them allow for the passage of some light. Some of the circuitry may be positioned to the periphery of the sensor—where light passage is not an issue. Still further, some of the conductors/circuitry can be fabricated using optically-transparent materials. In the illustrated embodiment, the top sensor absorbs 25% of the incident light, and passes 75%. But this number is not critical. Even if it passed a tenth of this amount or less (e.g., 5%), advantageous results associated with the FIG. 3 arrangement would still be realized. Light passing through the first sensor enters an optically transmissive medium. The thickness of the medium depends on the range of focal distances to be accommodated. An exemplary thickness for this medium is 100 microns, but depending on particular application requirements this thickness may be as small as 10 microns, or as large as many hundreds of microns. The medium can comprise various materials. Air is attractive for certain optical properties. However, interfaces between air and other optical materials are sometimes disfavored. Another suitable medium is glass. Another is a semiconductor. Still another is a fluid. Combinations can, of course, be used. Light exiting this medium is incident on the second image sensor. This second sensor can be conventional in structure. When a subject is at an infinite distance from the lens, the lens presents a focused image on the top sensor. Very high resolution sampling of this image is achieved by the top sensor (in accordance with the sensor's physical resolution). Part of that focused light energy on the top sensor from the infinite-distance object passes through the first sensor, and through the intervening medium, and falls on the second sensor. There the image is no longer focused. The strong edges and contrasts that are associated with a focused image are lost. A very low contrast, highly blurred image results. For an object at six inches distance from the lens, the situation is reversed. The lens casts a focused image on the bottom sensor (albeit with some of the light absorbed by its passage through the top sensor), yielding high resolution image data from the bottom sensor. At the top sensor, in contrast, the image is out of focus—with low contrast. Not shown in FIG. 3 is an ancillary system that collects data output from the two image sensors, and makes them available for post-processing. In one mode, this post-processing can comprise simply adding output signals from corresponding pixels in the first and second sensors, yielding a frame of output image data having the same dimensions as the image data from the first and second sensors. (The output signals from the first sensor may be scaled by a factor of three to compensate for the fact that the bottom sensor receives three times the light absorbed by the top sensor.) If the post-processing operation adds the images from the first and second sensors, an image sharpness curve like that shown in FIG. 3A results. At an object distance of six inches, maximally-sharp imagery is output by the second sensor. The first sensor, however, outputs a maximally-blurred image in this situation—contributing a low contrast noise signal. At distances greater than six inches, the image output by the second sensor becomes increasingly blurred—reducing the net sharpness of the combined output signal. As the object distance approaches infinity, the sharpness of the image output by the first sensor increases—until its maximum value at infinity. Again, a low contrast noise signal is contributed by the other (second) sensor, which outputs maximally-blurred imagery for an object distance of infinity. The just-discussed principles can be extended to any number of stacked photosensor arrays. FIG. 4 shows an arrangement employing three arrays. Again, the top and bottom sensors are positioned to capture focused images from objects at distances of infinity and six inches, respectively. However, the FIG. 4 arrangement includes a third sensor array positioned to capture focused imagery from objects at a distance of two feet. The design of this third photosensor array can be similar to that of the top array, e.g., transmissive of part of the incident light (e.g., 75%). In this arrangement, approximately 50% of the incoming light is absorbed before being passed to the CMOS sensor at the bottom of the stack. This arrangement produces a curve akin to FIG. 3A , but with three humps rather than two. It will be noted that the third photodetector array in FIG. 4 is closer to the top sensor than the bottom sensor. Yet the top two sensors collect imagery from the largest range of focal distances, i.e., two feet to infinity. This is a consequence of the lens equation. FIGS. 5-8 illustrate still other stacking variants. FIG. 5 shows four sensor arrays. Like FIG. 4 , the spacing of the arrays within the stack is non-uniform. FIG. 6 shows a stack of five sensor arrays—this time with uniform spacing through the stack. In some arrangements, such as FIG. 7 , the sensors can be spaced in a random fashion. FIG. 8 illustrates that in all such stacked-sensor embodiments, precise alignment of the sensors is not required. Any mis-alignment between sensors can be detected after fabrication (e.g., by analysis of test imagery), and compensated-for in post-processing. Nothing has yet been said about color. The human eye is much more sensitive to luminance (brightness) than color. Accordingly, color typically needn't be resolved as finely as luminance for most purpose. (For example, an image sensor with a million photosensor cells may produce only 250,000 samples of red information, and a like number of samples of blue, using a Bayer color filter.) In the embodiments of FIGS. 3-8 , the bottom photosensor in the stack can employ a Bayer color filter for sampling red, green and blue at different photosites. The upper sensors can include a regular or random distribution of color filters as well, which may be sparse (i.e., some photosites have no filter). FIG. 9 shows one form of sparse, regular color filter array, which may be tiled across the top image sensor in FIG. 3 , or across the top and intermediate image sensors in FIG. 4 . (In the latter case, the color filters on the sensors may be spatially staggered relative to each other.) In the depicted color filter array—as with the conventional Bayer pattern—green is sampled twice as frequently as red and blue. A variety of other such patterns, including some that are denser and some that are sparser, are straight-forward to implement. In a variant embodiment, the component stacked photosensors can produce color information through use of Foveon-like technology. However, if a conventional Foveon sensor is used top the stack, then no light would penetrate to lower layers. One approach is to fabricate a sparse array of Foveon sensor pixels—interspersed with clear pixels. This enables passage of some of the incident light through the clear pixels to lower layers. Second Class of Embodiments The arrangements detailed above involve, conceptually—if not necessarily physically, a mechanical configuration of parts. In more sophisticated embodiments, a stacked photosensor structure is achieved in integrated fashion, using familiar semiconductor fabrication techniques (deposition, masking, lithography, doping, etc.). Returning briefly to FIG. 1 , imagine that each of the layers P1-P8 is a volume of a semiconductor material, into which one or more photosensitive regions has been formed. Such an arrangement is shown in the exploded view of FIG. 10 , in which the photosensitive regions (sometimes terms photosites) are shown by ovals. Physically, these ovals are three-dimensional in character—akin to M&M candies in configuration—encompassing a junction between a P-doped region and an N-doped region, and a depletion zone through which photo-electrons can be routed for collection (e.g., to charge-accumulating capacitors—not shown). (In a different arrangement, the depicted ovals are physically realized by component structures that extend a greater distance in the vertical direction than in the horizontal.) This second class of embodiment permits the size and placement of the photo-electron generating and collecting structures to be tailored as desired, e.g., to optimize quantum efficiency, achieve particular sampling objectives, etc. For example, within the various layers along the Z-axis, the photosites can be spatially staggered (i.e., in the X-Y plane) to limit vertical occlusion of one by the other. FIG. 11A shows one pattern of photosites—looking down through the stack along the Z-axis. (Only five photosites are shown, for clarity of illustration.) The photosites are symmetrically spaced within the X-Y boundaries of the stacked column. If each photosite absorbs 100% of the photons propagating vertically down through the stack that encounters the site, the depicted FIG. 11A arrangement would absorb 68% of the total electrons. That is, 68% of the X-Y area is occupied by photosites. Other arrangements can, of course, be employed. FIG. 11B shows that the photosites in the different layers can be placed in random fashion in X-Y. Although this leads to lower quantum efficiencies, the stochastic sampling thereby effected has other desirable properties. The photosite regions needn't be circular in aspect. FIG. 11C shows how hexagonal photosites can be employed—yielding still greater photon capture and efficiency. In a particular arrangement, the FIG. 10 stack is 10 microns on a side, and the photosites have diameters of 1.75 microns. The total stack depth depends on the desired focal range; a stack depth of 100 microns is exemplary. (This roughly corresponds to a common smartphone configuration, which uses an f2.0 lens, spaced 3.85 mm from the sensor array, and provides a focus range of six inches to infinity.) Continuing with the M&M analogy, the photosites may be of different colors. More accurately, they may have different spectral responses. A simple starting point is to provide each photosite with either a corresponding red, green or blue filter, so that it responds to photons only of the associated wavelength. While that's a simple conceptualization of the idea, placement of color filters within an integrated circuit complicates its fabrication. Another approach to making different photosites responsive to different spectra is by the phenomenon popularized by Foveon—doping the semiconductor so that photons of different energies are more likely to penetrate to (and be detected in) different depths of the photosensor structure. Different doping can be used in different of the FIG. 2 stacks, so that across a given X-Y plane of the structure, different regions are attuned to different light frequencies. (That is, at a depth of 56 microns, not all photosites are maximally responsive to the same wavelength of light.) Still another approach to making different photosites respond to different spectra is through use of dichroic mirrors or filters. Put simply, a frequency-selective mirror (thin film-based) can be fabricated under a photosite. If a quantum of light passes the photosite without dislodging a photo-electron, it next encounters the thin film structure. The dimensions of this structure are chosen to induce a reflection of certain wavelengths of light. Such light is reflected back towards the photosite it just passed (i.e., vertically, up through the stack)—giving this quantum of light a second chance to kick a photo-electron out of the semiconductor material in that photosite. Yet another approach to realizing photosites having different spectral selectivities is through use of quantum dot material. Work at MIT's Tisdale Lab, at Delft University, and Invisage, has demonstrated use of quantum dot and film materials in image sensors. Related work is detailed, e.g., in Prins et al, Fast and Efficient Photodetection in Nanoscale Quantum-Dot Junctions, Nano Letters, Vol. 12, No. 11, October, 2012, pp. 5740-5743; Konstantatos et al, Solution-Processed Quantum Dot Photodetectors, Proc. IEEE, Vol. 97, No. 10, pp. 1666-1683, October, 2009; and in patent publications U.S. Pat. Nos. 7,476,904, 20070132052, 20110101205, 20110226934, 20100187404, and 20130032782. A particular implementation employs quantum dot material to transduce photons in the visible region into a short burst (e.g., nanosecond-scale burst) of electron/exciton energy, which is then measured and correlated to wavelength of the existing photon. In one illustrative embodiment, such quantum dot transducers (with a scale of 2-20 nm) are distributed in a sensing volume 100 microns in thickness. Each quantum dot effectively serves as a photon-transduction pulser, with the pulse size (strength) correlating to incoming photon wavelength (i.e., color). Depending on implementation, there may be thousands of such dots per square micron through the device. The pulses may be quantized (desirably near the sites) to 6- or 8-bits of resolution. While imaging science has long been fixated on tri-color systems (red/green/blue, and cyan/magenta/yellow), such arrangements optically pale in comparison to the capabilities of the human vision system. Better is to employ a richer spectral vocabulary. Thus, the spectral responses of the photosites employed in the present technology desirably are of more than three types (although in certain embodiments, single-, two- or three-spectral responses can be used). Four is on the low side. Different spectral responses numbering eight or more are be preferred. In this regard, reference is made to copending application Ser. No. 13/840,451, filed Mar. 15, 2013. It details, e.g., how multiple different (sometimes complex) spectra can be used to illuminate an object, so as to permit the object's spectrometry to be assessed more accurately than is possible with conventional R/G/B technology. In like fashion, use of multiple different spectral sensitivities by different photosites in the present technology similarly enables color imaging that exceeds the limitations of traditional tri-color systems. Five years from now, smartphones desirably will include both the technology detailed in the just-cited application, and the sensor technology detailed herein. Returning to and stretching the M&M analogy a bit, the electrons collected by the various photosites need to be routed for collection—typically by charge-storage capacitors (which may be formed at the bottom of the sensor array—beneath the last photosensitive regions). This routing can be effected by conductive electrodes (vias) that pass—typically vertically—through the integrated structure. In some implementations, these conductive electrodes are bundled—forming trunk-like structures. In such case, the M&M photosites may be regarded as leaves on branches (horizontal electrodes) that extend from this vertical trunk. Transparent electrode materials can be used to limit absorption of light within the bulk of the structure. Nanowires can be employed for the vertical vias in the photosensor array. (See, e.g., Fan et al, Electrical and Photoconductive Properties of Vertical ZnO Nanowires in High Density Arrays, Applied Physics Letters, Vol. 89, No. 21, 2006; and patent publications 20070155025 and 20110315988.) FIGS. 12A and 12B illustrate the concept of such a tree. The trunk (comprising plural conductive vias) is represented by the darker vertical line. Photosites are coupled to the component electrodes of the trunk, for routing of their photo-electrons to charge-storing capacitors. FIG. 12A shows a regularly-arranged configuration. FIG. 12B shows one with more randomness. These figures, of course, show only two dimensions. It will be recognized that additional photosites can exist in the third dimension, and can be similarly coupled to the tree trunk. Note, too, that the number of photosites in each layer of the tree can be different. The photosites within any X-Y layer needn't be regularly and uniformly distributed. Some regions of a layer may be locally dense with photosites, while others can be relatively sparse. As with other design choices, application constraints will commonly dictate such details in any particular embodiment. Although not shown in FIG. 10 , a conventional image sensor (e.g., CMOS or Foveon) may be formed—or affixed—at the bottom of the integrated photo sensor stack, to collect any remaining photons not transduced by the photosites throughout the volume. Returning to FIG. 1 , the illustrated light rays captured from nearby “Object 2,” and focused by the lens down into zone P7, first pass through all of zones P1-P6. The artisan will recognize that such light can kick-out photo-electrons in any of these zones P1-P6, on its way to P7. Moreover, while the light rays converge in zone P7, they may pass through even that zone, and end up kicking-out photo-electrons in zone P8. Thus, all of the component zones may output electron charge due to light from Object 2. However, the electron count produced by zone P7 will exceed that from any of the other zones, due to the increase in the electric field near the focal zone. Further Information on Blur and Sampling Additional technical insight into the present technology may be gained by examining the important difference between what is popularly called “blur” on the one hand, and what may be called Explicit Angular Sampling, or just angular sampling. One might say that blur is a physical phenomenon that has rather strict “depth of field” implications—primarily driven by the classic f-number of a lens being used, while angular sampling happens to be a core design principle of most embodiments of this technology, and helps explain why classic depth of field challenges can be overcome. It is exceedingly well known in signal sampling theory and practice that the discrete sampling of a signal (one dimensional, two, or even three) needs only be slightly finer that the local undulatory properties of a signal (expressed deliberately in lay terminology to make the point). More colloquially, if it wiggles, sample it at three to five points per wiggle, and you should be fine. More technically, whereas Nyquist suggests that taking only two discrete samples per cycle of the highest frequency of a signal may suffice, engineering practice suggests a slight “oversampling” of a signal is desired for good measure, as it were. Keeping the underlying issues still high-level (intuitive and even slightly pedestrian if the reader is a trained optical engineer), let us look at a simple scenario: a 4 millimeter focal length smart phone camera with an f2 aperture, or 2 millimeter aperture. We can further assume that the best focus “spot size” for a focused point is 2 microns. Simple ray-theory depth of field arguments tell us that for every 4 microns a sensor travels away from the “best focus” plane, the spot size will grow by 2 microns. Thus by 10 microns or so out of focus, the “spot size” of a point has grown to 5 microns. Optical engineers may rightly cringe at this over-simplification of “depth of field,” but please tolerate the desire here to just point out that “blur” can happen very easily in modern smart phone cameras even with 10 to 20 micron out-of-focus conditions. 10 to 20 microns matter. So continuing on with the pan-audience ray-trace storyline, once a typical f2 lens and planar-sensor is say 40 microns “out of focus,” the “blur circle” as it is often called has grown to be 20 microns, 10 times worse than the pristine 2 micron tight-focus capability of the lens. Wiggle-wise, wiggles with ten times less detail need only have ten times sparser sampling, hence any pixels at 2 microns are ludicrously oversampling these “blurred” signals at this out-of-focus plane. In a nutshell, the conventional planar approach to image sampling inherits this rather stark depth-of-field phenomena and the culturally-ingrained idea of focus and blur (lack thereof). Enter the third dimension of a sensor and the simple notion of sprinkling photosites at various depths inside a sensor, rather than simply in one plane (or three thinly packed planes for color sampling a la RGB and Foveon). In short, distribute 2 micron-ish photosites at various depths of a sensor from the front surface all the way to the furthest optically active surface, typically over a 100 micron thickness at least for a smart phone camera (4 mm, f2 or f2.8). As noted, give these 3D splayed photosites various spectral selection properties while you're at it, no need to rigidly adhere to RGB models only (though adhering to these models is acceptable as well). Nature's Teachings: Light Detection is a 3D Quantum Affair, not a 2D Sampling Nature has provided us the examples of the faunal retina and the floral chlorophyll for study of light to energy transduction in general. Let's roll with that. The closest engineering approach perhaps would be to view pixels not as photosites per se, but as micro-waveguides very much borrowing on rod/cone principles and chlorophyll-molecular-chain principles for more efficient photo-electron production. The 10 micron by 10 micron vertical cell cavity arrangement ( FIG. 10 ) with “trees” of active photosites are near the same physical scale as single-mode optical fiber, and thus lend themselves very well to electromagnetic field modeling in the extreme details of semi-conductor and/or “nanotech material deposition” engineering of both the vertical structures as well as the individually active photo-electron generation sites. Another well-known prior art which is general 2-dimensional in its primary application, but can be adapted easily to three dimensions, is the “dichroic filter.” As noted, controlled layering of differing substances with differing optical densities, especially at the 1-2 micron scales of the optical photosites, can be an extra widget in the design toolbox as the spectral selection properties of these photosites is determined. Moveable Sensors In accordance with a further aspect of the present technology, a sensor in a smartphone or other such video camera system is disposed on a moveable mount, permitting motion of the sensor relative to the rest of the optical assembly (e.g., the lens). Moveable lenses, sensors, and camera mounts have previously been employed for mechanical image stabilization, and such teachings can be employed in embodiments of the present technology. But the aim of the present technology is somewhat different. For example, prior art mechanical image stabilization, as used in video cameras and film motion picture cameras, has largely sought to keep static features of a scene at consistent locations, frame to frame—despite unintended movement of the camera (e.g., caused by hand jitter). When a video camera is moved in a deliberate fashion, e.g., in a panning motion, then arrangements like that marketed under the Steadicam brand are sometimes used to stabilize the camera mount (i.e., the lens and sensor together). This type of stabilization tends to isolate the camera from the operator's undesired, high frequency, movements. More uniform motions, however, such as panning, are not counter-acted by such arrangements. Contemporary versions of Steadicam-like arrangements employ MEMS-based rate gyrosensors mounted to a gimbaled camera rig, to measure the angular rate of the camera's rotation. Signals from these gyrosensors are used to drive DC servomoters, coupled to the camera's rotational axes, to effect compensatory motions. The present technology again contemplates panning, or other deliberate movements of the camera. But instead of mitigating motions that are ancillary to the desired movement (as with the above Steadicam-like arrangements), the present technology acts in concert with the desired movement, to reduce frame motion blur caused by such desired movement. Consider the case of a pan (i.e., a rotation of a video camera around a vertical axis), in which the video camera captures a frame of imagery every thirtieth of a second. (The exposure interval of each frame may be 30 milliseconds, and 3.33 milliseconds may elapse between frame exposures.) If the camera is panned at a rate of six degrees per second, then each successive frame depicts a view through the lens that is advanced, relative to the prior frame, by an increment of 0.2 degrees. This horizontal change in the viewed scene causes an apparent movement of fixed image features across the sensor, also in a horizontal direction. If the camera lens has a field of view of 30 degrees, and projects the imaged scene onto a sensor having 480 columns of pixels, then each degree of view corresponds to 16 columns. From one frame to the next, the 0.2 degree change in camera orientation corresponds to a horizontal shift of about 3 columns of pixels. In accordance with one embodiment of the present technology, a MEMS or piezo-electric actuator linearly shifts the camera sensor a horizontal distance of 3 pixel columns during the exposure of each of the frames—to counteract the panning-induced movement of the image on the sensor during that exposure period. At the end of the exposure period, the actuator quickly re-traces its travel in an opposite direction, to prepare for exposure of the next frame. This process repeats for each frame, so that the sensor alternately tracks the movement of the panning image, and then pops back to its original position. This operation may be termed a “track-pop” cycle. FIG. 13 shows the movement of the camera sensor in a horizontal dimension as a function of time. The illustrative sensor has a horizontal dimension of 4.8 millimeters, so that each pixel row is 0.01 millimeters across (i.e., 10 microns). During the course of a single exposure interval, the sensor is moved three pixel rows, or 30 microns. In the brief inter-frame interval, the actuator pops quickly back to its original position. FIG. 14 (not to scale) schematically shows a section view through part of a smartphone. A lens is positioned above an image sensor. The exterior surface of the lens terminates at a threaded opening into which an accessory lens (e.g., for additional light capture, or for microscopy) can be installed. The lens may include an auto-focus actuator (not shown) that mechanically moves the lens towards or away from the sensor. (If an image sensor of the sort described earlier is employed, then such mechanical focus arrangement is not needed.) The sensor is mounted for movement by a MEMS actuator 132 , which can translate the sensor towards or away from the actuator. The actuator may provide a range of motion of 50 microns, on each side of the sensor's nominal position (i.e., aligned with the lens.) It will be recognized that the foregoing description is necessarily simplified, for expository convenience. In actual practice, for example, the sensor may be translated in two directions, e.g. in “x” and “y.” Two actuators can be used for this function, or a single, 2D actuator, can be employed. (An example of the latter, using comb electrodes that are controllably excited to move optical elements in two dimensions, is detailed in U.S. Pat. No. 6,914,710.) Horizontal panning was assumed in the foregoing example. More generally, the nature of camera movement (e.g., angular panning, linear translation, etc.), and associated movement parameters, are desirably sensed by one or more 3D accelerometers and gyroscopes. Camera movement data can also be discerned from image sensor data, e.g., by tracking movement of scene features in the camera's field of view. Signals output from one or more such sensors are provided to the device processor, which computes the direction, magnitude, and timing of sensor movements that are needed to counteract motion of the image across the sensor during a frame exposure. Corresponding control signals are then sent to the sensor actuator(s). More particularly, movement of the camera and/or movement of dominant subject matter in a scene both give rise to gross lateral shifts of the light fields falling on a sensor. The dynamic X-Y re-positioning of the sensor attempts to track, as best as possible, the global average of this shift. Desirably, these shifts are sensed, and used to generate appropriate control signals. One approach is to utilize the now quite ubiquitous MEMS gyroscopes and accelerometers in order to determine the general movement characteristics of a camera on a frame-by-frame timescale. If one infers that a scene is largely not changing, the drive signals applied to the MEMS actuators can simply be an inversion of these measured movements of the camera. A second approach, which can be utilized separately or in combination with the first approach, is to use acquired pixel data from the sensor itself to measure and infer “residual tracking motion,” for lack of a better term. In other words, it is a known prior art to determine the direction and extent of “motion blur: in a given image, providing for a measured value which after two such frames of such motion blur, can be used to assist in forming the drive signals for the MEMS track-pop actuation signals. While the foregoing technology is described with reference to linear translation of the image sensor, in other embodiments different sensor movements can additionally, or alternatively, be employed. For example, the plane of the sensor may be tipped and/or tilted, so that its surface normal is non-parallel to the axis of the lens. Similarly, the sensor may be twisted (rotated) along its surface normal axis. It will be recognized that the physical movement of the sensor needn't precisely counteract the movement of the image projected onto the sensor. Any similarity between such motions is an improvement over none. Likewise, while the exemplary embodiment included a 3.33 millisecond interval between exposures, during which interval the sensor popped back to its original position, this is not essential. The pop-back of the sensor to its original position can occur during the exposure. Due to the brevity of such movement, and the relatively small distance traveled, the consequent impairment of image quality may be acceptable in certain applications. Additional Details Re Light-Field Tracking MEMS Companies such as Digital Optics Corporation and Tessera Technologies, Inc., among others, currently commercially supply MEMS-based Auto-Focus (AF) devices which provide the Z-axis displacement mechanism between a lens and a 2D sensor. As noted, aspects of the present technology posit use of such MEMS devices to also mechanically actuate motions in both the X and the Y direction: sensor plane relative to the plane of the lens. That is, the sensor would controllably shift at near 1-micron-level resolution relative to the parallel planes of the lens and sensor. Current MEMs AF device specifications are nicely close to the specifications useful required for track-pop imaging cycles. In particular, full range actuation distances approaching 100 microns or even more are desirable, as will be discussed. Likewise, half-range movements in the single digit millisecond range and preferably even better are desirable, though as will be seen, a track-pop cycle program can be adapted to the specifications of whatever a given physical MEMS device can provide. One aspect of track-pop cycling is to extend the prior art MEMS actuation from one axis to three. One way to do this is to do what many laboratory optical scientists do with much larger actuation stages than MEMS, and that is to simply bolt on a single actuation stage onto a second one but at an orthogonal manner, where the actuation of one stage moves the entire second stage along one given axis, then the second “riding” stage can then move a third body in some orthogonal direction, where that third body become yet a third MEMS actuation stage oriented “push axis” along the remaining orthogonal direction in 3-space (orthogonal to both of the first two stages). This long winded description mirrors the klunkiness and costliness of this approach, but it is important to note that this solution will unequivocally work. A preferred approach to building 3-axes MEMS devices is to drive toward “close” to the same packaging form factor and dimensions of the current class of AF MEMS devices. The micron-level comb and spring structures currently laid out on nicely planar structures for 1-D AF have to “break the plane” at least in a higher level of assembly, if not at the raw manufacturing level. (In other words, individual one-axis MEMS actuation likely will still be manufactured as a 1-D actuation-axis structure, but it will need to be more finely sliced up, twisted and then re-assembled orthogonally with its identical or nearly identical siblings (other uni-axis actuators). One approach to doing this is to start with a current Z-axis (focus axis) version of a MEMS actuator, and then “float” this stage on two separate rail tracks, the first rail track attaching the top MEMS (the AF stage) to an X-axis stage which is itself pushed and pulled along the rail axis, then below this stage there is a 90 degree rotated rail (from the first rail) which attaches the X stage to the Y stage, with the Y-stage then having a push-pull MEMS structure activating the two stages along the second rail. In this approach, the elegant thin form factor of current AF MEMS devices can be “thickened” outside of the critical optical aperture area and still allow for the seating of a lens in relatively close proximity to a sensor (typically only a few millimeters between the back of a lens surface and the front of a sensor surface). Once a 3-axis arrangement is in place, whether a klunky version or an elegant and thin one, the operation of shifting a sensor in close “tracking” to a light field projected onto that sensor can take place. The specifications of range of motion and response time then become parameters for determining the detailed timing of track and pop imaging. In general, the maximum speed of a MEMS actuation, projected through the focal length of a lens and then onto a scene being imaged, represents the very fastest motion that a scene can move in front of a camera and still be “tracked” by the MEMS motion. Likewise, when a given “tracking” has reached its full motion extent on the MEMS device, a command to end an exposure can take place, then kicking off the “pop” cycle which pops the MEMS actuation back to the other side of its full range. (If a particular MEMS axis represents the “long motion axis” of the current movement of the camera, the other axis will have a “pop” generally not quite as long as its full range). In such arrangement, individual exposures of “tracked frames” last as long as the full range stroke of the long-motion axis MEMS device. For intuitive grounding of the basic lens and motion parameters, one can imagine a lens with 3.75 mm focal length and a MEMS device with 100 microns full range motion. This gives a projected shift of just about 1.5 degrees, which, if one were to be panning (rotating) a camera operating at 30 frames per second, indicates that objects can move up to 45 degrees per second before they start to have residual blur beyond what the tracking can handle. Those practiced in these arts understand this situation is radically more nuanced than this simple example but the “order of magnitude” of how MEMS' full ranges, response times, focal lengths, etc. all play together is important to intuitively outline. Let us not forget as well that the “pop” phase usually posits turning off the exposing activities of the main sensor as the MEMS actuator(s) pop the sensor back to a new tracking starting point, and thus this “pop” time can represent a significant loss of information gathering if MEMS devices are not manufactured with an eye towards fast (ideally faster than one millisecond) full range popping capabilities. Much slower times can easily be made operational, the cost is simply dead time for light gathering. FIGS. 15A and 15B further illustrate the foregoing. Two plots are shown: FIG. 15A shows MEMS actuator displacement of the sensor in the “x” direction, and FIG. 15B is a similar illustration but in the “y” direction. The two actuator waveforms are synchronized, so that the track and pop phases coincide. The “x” actuator travels+/−30 microns around a nominal position (i.e., from 0-60 microns, centered at 30 microns). The “y” actuator is operated to move the sensor a smaller displacement, +/−10 microns around its nominal position. It will be recognized that a single control signal (a timing waveform) can be scaled and offset to generate both the “x” and “y” control signals. In the illustrated arrangement, the “track” interval (i.e., the frame exposure interval) is 5 milliseconds, and the “pop” interval is 2 milliseconds. Pop intervals that are less than 50% of the track intervals are typically utilized, with more preferable values for the pop interval being less than 20%, 10%, or even less than 5% or 2% of the track interval. Motion-Stasis-Motion In accordance with a further aspect of the present technology, an operational mode of the camera is controlled in accordance with a camera gesture. In a particular embodiment, a user signals interest in a scene when a phone is swept along a path to a point where it is briefly held, after which the phone is swept back in a contrary direction. The position at which it is briefly held indicates the user's interest in the scene viewed by the camera from that position. Data from the phone sensors (accelerometers, gyroscopes, and feature tracking by the camera) are processed to classify the phone as either being in a “motion” phase, or a “stasis” phase. Each phase is characterized by motion parameter thresholds. For example, the “motion” phase may be characterized by any movement at a rate greater than one centimeter per second. (Such velocity can be derived by integrating data from the accelerometer sensor.) Stasis may be characterized by movement at a rate less than 0.5 centimeter per second. To sense the just-described gesture, the device processor starts by looking for an initial motion phase. When that phase concludes, a time window (e.g., two seconds) starts within which the processor looks for a stasis phase. If stasis is not sensed within that interval (e.g., if the device moves at between 0.5 and 1 cm/second for more than 2 seconds), then the classifier resets—again looking for an initial motion phase. If a stasis phase is sensed, it must persist for a threshold interval, which may be bounded both by minimum and maximum values. For example, the minimum value may be a value greater than 0.1, 0.2, or 0.5 seconds. The maximum value may be a value less than 1, 2 or 5 seconds. If the device is held in a stasis phase for the required threshold interval, then the process next looks for a retracting motion. A retracting motion is a second “motion” phase, but one in which the motion is in a direction contrary to the initial motion phase. This can be defined mathematically in various ways, but the concept is familiar: if the user takes the phone from a rest position, sweeps it to a stasis position, and then returns it to (or near) the initial rest position, then that latter motion is a retraction motion. One algorithmic definition begins by defining a first axis, which is that of a first vector between the device's position at the start of the initial motion phase, and its position at the stasis phase. (The actual path might be curved, but the start and end points define a straight line.) A retraction motion is tested by attributes of a second vector: namely, that between the device's position at the stasis phase, and its position at the end of the second motion phase. If this second vector has a component—when projected onto the first axis—that is larger than its projection onto any axis orthogonal to the first axis, and is in a direction opposite to that of the first vector, then the second motion phase is a retraction motion. Put another way, if the first motion defines a first direction, then the second motion should have a principle component that is oriented in a direction opposite to that first direction, if the second motion is to be classified as a retraction motion. Image frames may be captured throughout these phases, at a video capture rate (e.g., 30 frames per second). Or, video capture may commence only after device velocity falls below a threshold, e.g., 1 cm/second (such as at the end of the initial motion phase), and may terminate when the device velocity again rises above that threshold (such as at the beginning of the retraction motion phase). Data from plural such image frames are combined in known fashion to synthesize one or more enhanced images, e.g., increasing the resolution, or extending the field of view, as contrasted with any single captured image frame. Desirably, two or more such composite images are created (e.g., from different virtual viewpoints), and are presented to the user on the device display. The user can flip or scroll between the composite images, using known image review UI paradigms, and select one or more for long term storage (e.g., in the Photo Library or Camera Roll data structures of the Apple iPhone). Ideally, the frames of video imagery from which the images presented to the user are composited, are gathered using a sensor of the type earlier described, providing 3D information. In such arrangement, there is no focal plane—outside of which subjects are out of focus. Instead, everything in the composite image is in focus. Other Comments It will be recognized that references to transparent materials simply refers to a material that does not block 100% of the light energy of interest. A material that intercepts 99% of the light, and passes 1%, is still regarded as transparent. (If only 0.001% of the light passes, it is no longer regarded as transparent. Between 0.001% and 1% is a range that may or may not be regarded as transparent—depending on the particular application being served.) While the embodiments of FIG. 3 , etc., contemplated that the component image sensors are of the same resolutions, this is not required. In other arrangements the sensors can be of differing resolutions. The detailed embodiment employs CMOS semiconductor image sensor technology. However, the principles of the detailed arrangement can be applied to any other type of image sensor arrangement, whether presently known (e.g., CCD or organic photosensors) or later developed. The number of different layers of photosites employed in a particular embodiment is application dependent. Although eight layers are illustrated in FIG. 1 , a lesser number (e.g., 3 or 6, etc.) or a greater number (e.g., 9 or 20 or 32, etc.) can be used. If each of the layers is 12 microns in thickness, a stack of eight yields a total stack depth of about 100 microns. A thicker or thinner stack may be desired, depending on the focal length of the lens, and the range of distances from which object images are to be captured. (The stack may be made thicker by increasing the number of photodetectors, or by increasing their component thicknesses.) The thicknesses of the photosites can be non-uniform, e.g., in acknowledgement that the photon flux deeper in the structure is diminished by photon absorption in higher layers. Alternatively, or additionally, the gains of the corresponding output amplifiers can be non-uniform—with those driven by photosites deeper in the structure having higher gains than those associated with photosites closer to the lens. Still further, the doping of semiconductor structures in deeper photosensors can be different than the doping of corresponding semiconductor structures in higher photosensors. While a single lens L is shown in FIGS. 1 and 3 for clarity of illustration, it will be recognized that plural lenses can be used, e.g., a compound lens, or a lens for each pixel, or a lens per group of neighboring pixels, etc. Combinations can also be used, e.g., a single object lens, in conjunction with a plurality of microlenses, as is known in certain light field architectures. The details of the photodetectors, and their respective charge accumulation, latching, switching and reset circuitry are not detailed, as same are within the skills of the artisan in photosensor design. Applicant's published applications 20110212717, 20110161076, and 20120284012, and pending application Ser. No. 13/750,752, filed Jan. 25, 2013, detail methods and arrangements that are useful in combination with the present technology. Publication 20110212717, for example, teaches that post-processing of sensor data is desirably performed by processing circuitry on the same substrate as the sensing elements. In the present case, such processing circuitry can take the raw signals from the various sensors/photosites, and process them to produce data streams optimized for their intended use (e.g., one data stream optimized for rendering to a user on a screen, another optimized for recognizing text from close focal distances, etc.). It will be recognized that multiple features are taught by this specification, and different particular embodiments have been detailed that combine different of these features. However, it will be recognized that the features can be combined in myriad arrangements, too numerous to catalog. This disclosure should be regarded as teaching all combinations of the disclosed features. To provide a comprehensive disclosure without unduly lengthening this specification, applicant incorporates by reference the documents identified herein, as well as the documents they respectively reference. All such documents are incorporated in their entireties, as if fully set forth herein. Review A far-from-complete list of some of the inventive arrangements provided by this technology includes the following: An optical array sensor for use with a lens, where the sensor comprises a structure having a thickness of at least 10 microns, with plural photo-electron generating regions (photosites) dispersed at differing layers within that thickness (corresponding to differing lens focal planes). A particular such sensor is useful for sensing objects at distances from the lens ranging from less than ten inches, out to infinity. In some such sensors, the photosites are spectrally selective, and there are at least two different types of spectral selection. Commonly there may be four or more. Desirably, the photosites are transmissive to light for non-spectrally-selected wavelengths of light. In a particular sensor, the structure has a thickness of more than 50 microns, comprises three or more different layers of photosites. These three layers correspond to objects imaged at respective distances of (a) less than 10 inches, (b) between ten inches and three feet, and (c) greater than three feet. The above-noted sensor may be provided with a first CMOS sensor array atop said structure, which serves as an entry surface onto which light entering the structure is first incident. This CMOS sensor array may pass 25% or more of the visible incident light into said structure. Similarly, the above-noted sensor may be provided with a second CMOS sensor array behind the structure, for receiving light that was not transduced to photo-electrons elsewhere in the sensor. In some arrangements, both of the just-referenced CMOS sensors are provided, thereby sandwiching the structure. In such a configuration, a first fraction of incoming light is transduced to electrons by the first CMOS sensor atop the structure, another fraction of incoming light is transduced to electrons by the photosites in the structure, and a further fraction of the incoming light is transduced to electrons by the second CMOS sensor behind the structure. In another particular sensor, there are at least four differing depth layers for the photo-electron generating regions in the structure. Each of these regions comprises plural photosites, and an X-Y arrangement of the photosites in one of said layers is staggered relative to an X-Y arrangement of the photosites in a successive layer. The just-described sensor may have a density of photosites such that 25% or less of incident light reaches a CMOS sensor array at the back of the structure. The above-noted sensors may include photosites arranged such that a line normal to the thickness passes through a first photosite in one layer and a second, different photosite in a different layer. These first and second photosites are desirably differently spectrally selective. The above-noted sensors can include a first gated conduction path that couples a first photosite to a first transfer capacitor, and a second gated conduction path that couples a second photosite to a second transfer capacitor, where the first and second transfer capacitors are optically shielded from incident light. Such a sensor can further include control circuitry for alternately gating the conduction paths on and off plural times per second, to produce raw video signal charge streams to the transfer capacitors. The technology also includes an apparatus having a stack of plural photodetectors P 1 -P N and a lens. The lens introduces light onto a first exterior surface of the stack, for passage through the stack towards a second exterior surface of the stack. The stack positions different of the photodetectors at different distances from the lens, so that they provide dominant responses to light captured from objects at different distances from the lens in accordance with the photodetectors' distances from the lens. A distance between photodetectors P 1 -P N in the stack is at least 20 microns. Another such sensor includes four or more light-detecting volumes P 1 , P 2 , P 3 -P N arranged so that light detected in volume P 2 has first passed through volume P 1 , light detected in volume P 3 has first passed through volumes P 1 and P 2 , etc. A distance between volumes P 1 -P N is at least 20 microns, permitting the sensor to provide object distance information when used with a lens that directs light from an object onto the sensor. In the just-detailed sensor, the light-detecting volumes can be arranged in a stack along a stack axis. A first of the volumes has a first photosensitive region, and a second of said volumes has a second photosensitive region. A line between centers of these first and second photosensitive regions is not parallel to said stack axis. Put another way, if the light-detecting volumes are arranged in a stack along a Z axis in an X, Y, Z Cartesian coordinate system, each of the light-detecting volumes each has an extent in X-Y space. In such view, a first of the volumes has a photosensitive region at a first X-Y location, and others of the volumes have respective photosensitive regions at other X-Y locations that are different than the first X-Y location. In such an arrangement, a light ray traveling through the sensor parallel to the Z axis encounters different of said photosensitive regions, depending on the ray's location in X-Y space.

The advent of electronic-based imaging generally followed the four generalized ‘eras’ identified in FIG. 16 The trend is clearly toward higher and higher levels of integration for the act of “taking pictures.” FIG. 17 is a humble graphic attempt to summarize certain aspect of the present technology, and how a synthesis of these additional technical capabilities can represent a next era quite nicely. To the extent a great deal of past photography and filming has involved the mastery of technical limitations and turning limitations into art, a new challenge should develop where everyone has their own pocket Hasselblad/Steadicam, and exploration of new subject matter becomes the game.

[0001] This application is a continuation-in-part of copending patent application Ser. No. 10/126,823 filed Apr. 19, 2002. TECHNICAL FIELD [0002] The present invention is generally directed to structures for supporting concrete reinforcing members. More particularly, the invention is directed to a chair for supporting two reinforcing bars in an orthogonal relationship as concrete is poured to form a concrete slab. BACKGROUND OF THE INVENTION [0003] Steel reinforcement bars are typically used in concrete slabs, concrete foundations, and other concrete structures to provide structural support to the concrete. In slab applications, the bars are usually arranged in a rectangular lattice which is supported some distance above the ground or other surface on which the slab is to be poured. In foundation applications, the bars are usually arranged parallel to the walls of the foundation, and supported above the ground or other surface. In this manner, the concrete may flow under and around the bars, thereby encapsulating the bars when the concrete hardens. [0004] Prior structures for supporting the reinforcement bars above the ground, also referred to as chairs, have been lacking in several respects. Prior chairs have not provided stable support and have not effectively captured the reinforcing members to adequately keep them in the proper position as the concrete is poured. Also, some prior chairs have been difficult to use in that multiple pieces are required to capture the reinforcement bars. Further, many prior chair designs have been difficult to fabricate, which increases their cost. [0005] What is needed, therefore, is an easy-to-use, low-cost structure for providing stable support for reinforcement bars in concrete slabs, foundations, and other concrete structures. SUMMARY OF THE INVENTION [0006] The foregoing and other needs are met by an apparatus for supporting reinforcement bars in a concrete structure. The apparatus includes a base member having a lower surface and an opposing upper surface. A plurality of pairs of opposing first leg members extend upward from the upper surface of the base member. Each of the first leg members have a lower end connected to the base member and an upper end distally disposed from the lower end. The apparatus includes a plurality of cradles for receiving the reinforcement bars, where each cradle is attached to the upper ends of a corresponding pair of the opposing first leg members. In a preferred embodiment, the apparatus includes horizontal support members disposed between and connecting the cradles. [0007] Preferably, the base member, opposing leg members, cradles, and horizontal support members comprise a unitary structural element, such as a continuous piece of thermoplastic material formed by injection molding. BRIEF DESCRIPTION OF THE DRAWINGS [0008] Further advantages of the invention will become apparent by reference to the detailed description of preferred embodiments when considered in conjunction with the drawings, which are not to scale, wherein like reference characters designate like or similar elements throughout the several drawings as follows: [0009] FIG. 1 is a perspective view of a structure for supporting concrete reinforcement bars according to a preferred embodiment of the invention; [0010] FIG. 2 is a first side view of a structure for supporting concrete reinforcement bars according to a preferred embodiment of the invention; [0011] FIG. 3 is a second side view of a structure for supporting concrete reinforcement bars according to a preferred embodiment of the invention; [0012] FIG. 4 is a top view of a structure for supporting concrete reinforcement bars according to a preferred embodiment of the invention; [0013] FIG. 5 is a perspective view of a structure that is supporting concrete reinforcement bars according to a preferred embodiment of the invention; [0014] FIG. 6 is a perspective view of a structure for supporting concrete reinforcement bars according to an alternative embodiment of the invention; [0015] FIG. 7 is a side view of a structure for supporting concrete reinforcement bars according to an alternative embodiment of the invention; [0016] FIG. 8 is an end view of a structure for supporting concrete reinforcement bars according to an alternative embodiment of the invention; and [0017] FIG. 9 is a perspective view of a structure that is supporting concrete reinforcement bars according to an alternative embodiment of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT [0018] Depicted in FIGS. 1-5 is a structure 10 for supporting concrete reinforcement bars, also referred to herein as a re-bar chair. As shown in FIG. 5 , the chair 10 may be used to hold two concrete reinforcement bars B 1 and B 2 in a substantially orthogonal relationship as concrete is poured around the chair 10 and the bars B 1 and B 2 to form a concrete structure. As one skilled in the art will appreciate, many such chairs 10 may be used to support a rectangular lattice of reinforcement bars in a concrete slab. [0019] The chair 10 includes a base member 12 , which is preferably square, but which also could be circular, octagonal, or other shape. Within the base member 12 , there is preferably an opening 14 . Situated around the opening 14 are a set of leg members, including opposing long leg members 16 a and 16 b and opposing short leg members 18 a and 18 b. The leg members 16 a - b and 18 a - b are attached at their lower extremities to the base member 12 and extend upward therefrom. The leg members 16 a - b and 18 a - b of the preferred embodiment are rectangular in cross-section, and, as shown most clearly in FIGS. 2 and 3 , are somewhat thicker at their lower extremities than at their upper extremities. [0020] Attached to the upper extremity of the long leg member 16 a is an upper bar-support member 20 a, and attached to the upper extremity of the long leg member 16 b is an upper bar-support member 20 b. As shown most clearly in FIGS. 1 and 3 , the upper bar-support member 20 a includes opposing sidewalls 24 a and 26 a, which together form a channel C 1 therebetween. Similarly, the upper bar-support member 20 b includes opposing sidewalls 24 b and 26 b. [0021] Attached to the upper extremity of the short leg member 18 a is a lower bar-support member 22 a, and attached to the upper extremity of the short leg member 18 b is a lower bar-support member 22 b. As shown most clearly in FIGS. 1 and 2 , the lower bar-support member 22 a includes opposing sidewalls 28 a and 30 a, which together form a channel C 2 therebetween. Similarly, the lower bar-support member 22 b includes opposing sidewalls 28 b and 30 b. [0022] The sidewall 26 a of the upper bar-support member 20 a is attached to the sidewall 28 a of the lower bar-support member 22 a , and the sidewall 24 a of the upper bar-support member 20 a is attached to the sidewall 28 b of the lower bar-support member 22 b. Similarly, the sidewall 26 b of the upper bar-support member 20 b is attached to the sidewall 30 a of the lower bar-support member 22 a, and the sidewall 24 b of the upper bar-support member 20 b is attached to the sidewall 30 b of the lower bar-support member 22 b. Based on this arrangement, the lower bar-support members 22 a and 22 b form a lower cradle 22 for receiving a lower reinforcement bar (such as the bar B 1 in FIG. 5 ), and the upper bar-support members 20 a and 20 b form an upper cradle 20 for receiving an upper reinforcement bar (such as the bar B 2 in FIG. 5 ). [0023] To prevent the reinforcement bars from lifting out of the cradles 20 and 22 , on the inner surfaces of the opposing sidewalls 24 a - 26 a, 24 b - 26 b, 28 a - 30 a , and 28 b - 30 b are retaining members 32 . As shown most clearly in FIGS. 2 and 3 , the retaining members 32 extend slightly over the channels C 1 and C 2 to prevent the reinforcement bars from moving upward and out of the channels C 1 and C 2 . As the Figures indicate, the upper surfaces of the retaining members 32 are beveled, sloped, or curved slightly downward so that when the reinforcement bars are pressed downward toward the channels C 1 and C 2 , force is transferred outward to cause the sidewalls 24 a - b , 26 a - b, 28 a - b, and 30 a - b to flex outward and allow the reinforcement bars to snap into the channels C 1 and C 2 . The lower surfaces of the retaining members 32 are preferably not beveled, but rather have a square or barbed corners for effectively capturing the reinforcement bars within the channels C 1 and C 2 . Compared to prior chair designs that have used opposing tapered slots in a conical or cylindrical wall, the opposing sidewalls and retaining members of the present invention provide a significantly improved retention mechanism. [0024] In the preferred embodiment of the invention, all of the components of the chair 10 are formed from one continuous piece of thermoplastic, such as polypropylene, which, though rigid enough to support the weight of the reinforcement bars, is flexible enough to allow the sidewalls 24 a - b , 26 a - b , 28 a - b, and 30 a - b to flex outward to receive the reinforcement bars as described above. Thus, when a reinforcement bar is laid across the cradle 20 on top of the retaining members 32 , and is pressed downward, the sidewalls 24 a - b and 26 a - b may flex outward to allow the reinforcement bar to slide past the retaining members 32 and snap into place in the channel C 1 . Similarly, when a reinforcement bar is laid across the cradle 22 on top of the retaining members 32 , and is pressed downward, the sidewalls 28 a - b and 30 a - b may flex outward to allow the reinforcement bar to slide past the retaining members 32 and snap into place in the channel C 2 . Of course, if the chair 10 is used to support two orthogonal reinforcement bars, the lowermost bar must be snapped into the lower cradle 22 first, and then the uppermost bar may be snapped into the upper cradle 20 . [0025] In the preferred embodiment of the invention, the height of the lower cradle 22 above the base 12 is about three to four inches, which would place the reinforcement bars at about the center of a six to eight inch concrete slab. However, one skilled in the art will appreciate that with appropriate scaling of the base 12 and the leg members 16 a - b and 18 a - b, the height of the lower cradle 22 above the base 12 could be practically any desired value. Thus, the present invention is not limited to any particular height of the cradles 20 and 22 above the base 12 . [0026] As one skilled in the art will appreciate, the chair 10 as depicted in the Figures is designed to be formed using an injection molding process in a two-piece injection mold. For compatibility with a two-piece mold, the leg members 16 a - b and 18 a - b preferably lean slightly inward and have cross-sections which are preferably tapered from thicker to thinner from the lower to the upper extremities. [0027] Depicted in FIGS. 6-9 is an alternative embodiment of a structure 100 for supporting concrete reinforcement bars, also referred to herein as a re-bar chair. As shown in FIG. 9 , the a preferred embodiment of the chair 100 may be used to hold three concrete reinforcement bars B 1 , B 2 , and B 3 in a substantially parallel relationship as concrete is poured around the chair 100 and the bars B 1 , B 2 , and B 3 to form a concrete structure, such as a foundation or footer. As one skilled in the art will appreciate, many such chairs 100 may be used to support several reinforcement bars in a concrete foundation. [0028] The chair 100 includes a base member 102 , which is preferably rectangular, but which also could be oval, elliptical, or other shape. Within the base member 102 , there is preferably an opening 104 . Situated around the opening 104 are a set of leg members 106 and 108 . The leg members 106 and 108 are attached at their lower extremities to the base member 102 and extend upward there from. The leg members 106 and 108 of the preferred embodiment are rectangular in cross-section, and are somewhat thicker at their lower extremities than at their upper extremities. [0029] Attached to the upper extremity of the each pair of leg members 106 is a cradle 120 . [0030] Each cradle 120 preferably includes opposing sidewalls 124 and 126 which form a channel C 1 in which a reinforcement bar (such as the bar B 1 in FIG. 9 ) is received. Preferably the sidewalls 124 and 126 of the cradles 120 include a gap 136 , as depicted in FIGS. 6 and 8 . However, in an alternative embodiment, the sidewalls 124 and 126 have no gap. One advantage of the embodiment with the gap 136 is that the sidewalls 124 and 126 are easier to flex outward to allow insertion of the reinforcement bars into the channel C 1 . [0031] To prevent the reinforcement bars from lifting out of the cradles 120 , on the inner surfaces of the opposing sidewalls 124 and 126 are retaining members 132 . As shown most clearly in FIGS. 6 and 7 , the retaining members 132 extend slightly over the channel C 1 to prevent the reinforcement bars from moving upward and out of the channel C 1 . As the Figures indicate, the upper surfaces of the retaining members 132 are preferably beveled, sloped, or curved slightly downward so that when the reinforcement bars are pressed downward toward the channel C 1 , force is transferred outward to cause the sidewalls 124 and 126 to flex outward and allow the reinforcement bars to snap into the channel C 1 . The lower surfaces of the retaining members 132 are preferably not beveled, but rather have a square or barbed corners for effectively capturing the reinforcement bars within the channel C 1 . Compared to prior chair designs that have used opposing tapered slots in a conical or cylindrical wall, the opposing sidewalls and retaining members of the present invention provide a significantly improved retention mechanism. [0032] The preferred embodiment of the chair 100 includes three cradles 120 for holding three reinforcement bars. However, one skilled in the art will appreciate that the chair 100 may include any number of cradles 120 to hold any number of reinforcement bars in a parallel arrangement in a concrete foundation or footer. [0033] As shown in FIGS. 6 and 7 , horizontal support members 134 are preferably provided between adjacent cradles 120 to provide lateral support. [0034] In the preferred embodiment of the invention, all of the components of the chair 102 are formed from one continuous piece of thermoplastic, such as polypropylene, which, though rigid enough to support the weight of the reinforcement bars, is flexible enough to allow the sidewalls 124 and 126 to flex outward to receive the reinforcement bars as described above. Thus, when a reinforcement bar is laid across the cradle 120 on top of the retaining members 132 , and is pressed downward, the sidewalls 124 and 126 may flex outward to allow the reinforcement bar to slide past the retaining members 132 and snap into place in the channel C 1 . [0035] In the preferred embodiment of the invention depicted in FIGS. 6-9 , the height of the cradles 120 above the base 102 is about 3 to 4 inches, which would place the reinforcement bars at about the center of a 6 to 8 inch concrete foundation. However, one skilled in the art will appreciate that with appropriate scaling of the base 102 and the leg members 106 and 108 , the height of the cradles 120 above the base 102 could be practically any desired value. Thus, the present invention is not limited to any particular height of the cradles 120 above the base 102 . [0036] The spacing between adjacent cradles 120 is about five inches in the preferred embodiment that has three cradles. This provides for a spacing of about ten inches between the outer two cradles 120 , which is an optimum arrangement for 12-inch wide footers. However, it will be appreciated that the invention is not limited to any particular spacing between adjacent cradles 120 . [0037] As one skilled in the art will appreciate, the chair 100 as depicted in FIG. 6-9 is designed to be formed using an injection molding process in a two-piece injection mold. For compatibility with a two-piece mold, the leg members 106 and 108 preferably lean slightly inward and have cross-sections which are preferably tapered from thicker to thinner from the lower to the upper extremities. [0038] The foregoing description of preferred embodiments for this invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings. The embodiments are chosen and described in an effort to provide the best illustrations of the principles of the invention and its practical application, and to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as is suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.

A structure is described for supporting concrete reinforcement bars in a concrete structure, such as a footer or foundation. The structure includes a base member having a lower surface and an opposing upper surface. A plurality of pairs of opposing first leg members extend upward from the upper surface of the base member. Each of the first leg members have a lower end connected to the base member and an upper end distally disposed from the lower end. The structure includes a plurality of cradles for receiving the reinforcement bars, where each cradle is attached to the upper ends of a corresponding pair of the opposing first leg members. In a preferred embodiment, the structure includes horizontal support members disposed between and connecting the cradles. To retain the reinforcement bars within the cradles, preferred embodiments of the structure include retaining members that protrude inward from the inner surfaces of the opposing sidewalls. These retaining members offer interference to any upward movement of the reinforcement bars. Preferably, the base member, opposing leg members, cradles, retaining members, and horizontal support members comprise a unitary structural element, such as a continuous piece of thermoplastic material formed by injection molding.

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation-in-part application of U.S. patent application Ser. No. 09/688,549 filed on Oct. 16, 2000. The disclosure of the above application is incorporated herein by reference. FIELD OF THE INVENTION [0002] The present invention relates to generally to scroll machines. More particularly, the present invention relates to a dual volume ratio scroll machine, having a multi-function seal system which utilizes flip or flip seals. BACKGROUND AND SUMMARY OF THE INVENTION [0003] A class of machines exists in the art generally known as scroll machines which are used for the displacement of various types of fluids. Those scroll machines can be configured as an expander, a displacement engine, a pump, a compressor, etc., and the features of the present invention are applicable to any one of these machines. For purposes of illustration, however, the disclosed embodiments are in the form of a hermetic refrigerant compressor. [0004] Scroll-type apparatus have been recognized as having distinct advantages. For example, scroll machines have high isentropic and volumetric efficiency, and hence are small and lightweight for a given capacity. They are quieter and more vibration free than many compressors because they do not use large reciprocating parts (e.g. pistons, connecting rods, etc.). All fluid flow is in one direction with simultaneous compression in plural opposed pockets which results in less pressure-created vibrations. Such machines also tend to have high reliability and durability because of the relatively few moving parts utilized, the relatively low velocity of movement between the scrolls, and an inherent forgiveness to fluid contamination. [0005] Generally speaking, a scroll apparatus comprises two spiral wraps of similar configuration, each mounted on a separate end plate to define a scroll member. The two scroll members are interfitted together with one of the scroll wraps being rotationally displaced 180 degrees from the other. The apparatus operates by orbiting one scroll member (the orbiting scroll member) with respect to the other scroll member (the non-orbiting scroll) to produce moving line contacts between the flanks of the respective wraps. These moving line contacts create defined moving isolated crescent-shaped pockets of fluid. The spiral scroll wraps are typically formed as involutes of a circle. Ideally, there is no relative rotation between the scroll members during operation, the movement is purely curvilinear translation (no rotation of any line on the body). The relative rotation between the scroll members is typically prohibited by the use of an Oldham coupling. [0006] The moving fluid pockets carry the fluid to be handled from a first zone in the scroll machine where a fluid inlet is provided, to a second zone in the scroll machine where a fluid outlet is provided. The volume of the sealed pocket changes as it moves from the first zone to the second zone. At any one instant of time, there will be at least one pair of sealed pockets, and when there are several pairs of sealed pockets at one time, each pair will have different volumes. In a compressor, the second zone is at a higher pressure than the first zone and it is physically located centrally within the machine, the first zone being located at the outer periphery of the machine. [0007] Two types of contacts define the fluid pockets formed between the scroll members. First, there is axially extending tangential line contacts between the spiral faces or flanks of the wraps caused by radial forces (“flank sealing”). Second, there are area contacts caused by axial forces between the plane edge surfaces (the “tips”) of each wrap and the opposite end plate (“tip sealing”). For high efficiency, good sealing must be achieved for both types of contacts, however, the present invention is concerned with tip sealing. [0008] To maximize efficiency, it is important for the wrap tips of each scroll member to sealingly engage the end plate of the other scroll so that there is minimum leakage therebetween. One way this has been accomplished, other than using tip seals (which are very difficult to assembly and which often present reliability problems) is by using fluid under pressure to axially bias one of the scroll members against the other scroll member. This of course, requires seals in order to isolate the biasing fluid at the desired pressure. Accordingly, there is a continuing need in the field of scroll machines for axial biasing techniques including improved seals to facilitate the axial biasing. [0009] One aspect of the present invention provides the art with several unique sealing systems for the axial biasing chamber of a scroll-type apparatus. The seals of the present invention are embodied in a scroll compressor and suited for use in machines which use discharge pressure alone, discharge pressure and an independent intermediate pressure, or solely an intermediate pressure, in order to provide the necessary axial biasing forces to enhance tip sealing. In addition, the seals of the present invention are suitable particularly for use in applications which bias the non-orbiting scroll member towards the orbiting scroll member. [0010] A typical scroll machine which is used as a scroll compressor for an air conditioning application is a single volume ratio device. The volume ratio of the scroll compressor is the ratio of the gas volume trapped at suction closing to the gas volume at the onset of discharge opening. The volume ratio of the typical scroll compressor is “built-in” since it is fixed by the size of the initial suction pocket and the length of the active scroll wrap. The built-in volume ratio and the type of refrigerant being compressed determine the single design pressure ratio for the scroll compressor where compression lossed due to pressure ratio mismatch is avoided. The design pressure ratio is generally chosen to closely match the primary compressor rating point, however, it may be biased towards a secondary rating point. [0011] Scroll compressor design specifications for air conditioning applications typically include a requirement that the motor which drives the scroll members must be able to withstand a reduced supply voltage without overheating. While operating at this reduced supply voltage, the compressor must operate at a high-load operating condition. When the motor is sized to meet the reduced supply voltage requirement, the design changes to the motor will generally conflict with the desire to maximize the motor efficiency at the primary compressor rating point. Typically, the increasing of motor output torque will improve the low voltage operation of the motor but this will also reduce the compressor efficiency at the primary rating point. Conversely, any reduction that can be made in the design motor torque while still being able to pass the low-voltage specification allows the selection of a motor which will operate at a higher efficiency at the compressor primary rating point. [0012] Another aspect of the present invention improves the operating efficiency of the scroll compressor through the existence of a plurality of built-in volume ratios and their corresponding design pressure ratios. For exemplary purposes, the present invention is described in a compressor having two built-in volume ratios and two corresponding design pressure ratios. It is to be understood that additional built-in volume ratios and corresponding design pressure ratios could be incorporated into the compressor if desired. [0013] Other advantages and objects of the present invention will become apparent to those skilled in the art from the subsequent detailed description, appended claims and drawings. [0014] Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. BRIEF DESCRIPTION OF THE DRAWINGS [0015] The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: [0016] [0016]FIG. 1 is a vertical sectional view of a scroll type refrigerant compressor incorporating the sealing system and the dual volume ratio in accordance with the present invention; [0017] [0017]FIG. 2 is a cross-sectional view of the refrigerant compressor shown in FIG. 1, the section being taken along line 2 - 2 thereof; [0018] [0018]FIG. 3 is a partial vertical sectional view of the scroll type refrigerant compressor shown in FIG. 1 illustrating the pressure relief systems incorporated into the compressor; [0019] [0019]FIG. 4 is a cross-sectional view of the refrigerant compressor shown in FIG. 1, the section being taken along line 2 - 2 thereof with the partition removed; [0020] [0020]FIG. 5 is a typical compressor operating envelope for an air-conditioning application with the two design pressure ratios being identified; [0021] [0021]FIG. 6 is an enlarged view of a portion of a compressor in accordance With another embodiment of the present invention; [0022] [0022]FIG. 7 is an enlarged view of a portion of a compressor in accordance with another embodiment of the present invention; [0023] [0023]FIG. 8 is an enlarged view of a portion of a compressor in accordance with another embodiment of the present invention; [0024] [0024]FIG. 9 is an enlarged view of a portion of a compressor in accordance with another embodiment of the present invention; [0025] [0025]FIG. 10 is an enlarged view of a portion of a compressor in accordance with another embodiment of the present invention; [0026] [0026]FIG. 11 is an enlarged plan view of a portion of the sealing system according to the present invention shown in FIG. 3; [0027] [0027]FIG. 12 is an enlarged vertical sectional view of circle 12 shown in FIG. 11; [0028] [0028]FIG. 13 is a cross-sectional view of a seal groove in accordance with another embodiment of the present invention; [0029] [0029]FIG. 14 is a cross-sectional view of a seal groove in accordance with another embodiment of the present invention; [0030] [0030]FIG. 15 is a partial vertical sectional view of a scroll type refrigerant compressor incorporating a sealing system in accordance with another embodiment of the present invention; [0031] [0031]FIG. 16 is a partial vertical sectional view of a scroll type refrigerant compressor incorporating a sealing system in accordance with another embodiment of the present invention; [0032] [0032]FIG. 17 is a partial vertical sectional view of a scroll type refrigerant compressor incorporating a sealing system in accordance with another embodiment of the present invention; [0033] [0033]FIG. 18 is a partial vertical sectional view of a scroll type refrigerant compressor incorporating a sealing system in accordance with another embodiment of the present invention; [0034] [0034]FIG. 19 is a partial vertical sectional view similar to FIG. 18 but also incorporating a capacity modulation system; [0035] [0035]FIG. 20 is a partial vertical sectional view of a scroll type refrigerant compressor incorporating a sealing system in accordance with another embodiment of the present invention; [0036] [0036]FIG. 21 is a partial vertical sectional view of a scroll type refrigerant compressor incorporating a sealing system in accordance with another embodiment of the present invention; [0037] [0037]FIG. 22 is a partial vertical sectional view similar to FIG. 21 but also incorporating a capacity modulation system; [0038] FIGS. 23 A- 23 H are enlarged sectional views illustrating various seal groove geometries in accordance with the present invention; [0039] [0039]FIG. 24 is a cross-sectional view of an as-molded flat top seal; and [0040] [0040]FIG. 25 is a cross-sectional view of a flip seal in it L-shaped operational condition. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0041] Although the principles of the present invention may be applied to many different types of scroll machines, they are described herein, for exemplary purposes, embodied in a hermetic scroll compressor, and particularly one which has been found to have specific utility in the compression of refrigerant for air conditioning and refrigeration systems. [0042] The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. Referring now to the drawings in which like reference numerals designate like or corresponding parts throughout the several views, there is shown in FIGS. 1 and 2 a scroll compressor incorporating a unique dual volume-ratio system in accordance with the present invention and which is designated generally by the reference numeral 10 . Scroll compressor 10 comprises a generally cylindrical hermetic shell 12 having welded at the upper end thereof a cap 14 and at the lower end thereof a base 16 having a plurality of mounting feet (not shown) integrally formed therewith. Cap 14 is provided with a refrigerant discharge fitting 18 which may have the usual discharge valve therein (not shown). Other major elements affixed to the shell include a transversely extending partition 22 which is welded about its periphery at the same point that cap 14 is welded to shell 12 , a main bearing housing 24 which is suitably secured to shell 12 and a lower bearing housing 26 having a plurality of radially outwardly extending legs each of which is also suitably secured to shell 12 . A motor stator 28 which is generally square in cross-section but with the corners rounded off is press fitted into shell 12 . The flats between the rounded corners on the stator provide passageways between the stator and shell, which facilitate the return flow of lubricant from the top of the shell to the bottom. [0043] A drive shaft or crankshaft 30 having an eccentric crank pin 32 at the upper end thereof is rotatably journaled in a bearing 34 in main bearing housing 24 and a second bearing 36 in lower bearing housing 26 . Crankshaft 30 has at the lower end a relatively large diameter concentric bore 38 which communicates with a radially outwardly inclined smaller diameter bore 40 extending upwardly therefrom to the top of crankshaft 30 . Disposed within bore 38 is a stirrer 42 . The lower portion of the interior shell 12 defines an oil sump 44 which is filled with lubricating oil to a level slightly above the lower end of a rotor 46 , and bore 38 acts as a pump to pump lubricating fluid up the crankshaft 30 and into passageway 40 and ultimately to all of the various portions of the compressor which require lubrication. [0044] Crankshaft 30 is rotatively driven by an electric motor including stator 28 , windings 48 passing therethrough and rotor 46 press fitted on crankshaft 30 and having upper and lower counterweights 50 and 52 , respectively. [0045] The upper surface of main bearing housing 24 is provided with an annular flat thrust bearing surface 54 on which is disposed an orbiting scroll member 56 having the usual spiral vane or wrap 58 extending upward from an end plate 60 . Projecting downwardly from the lower surface of end plate 60 of orbiting scroll member 56 is a cylindrical hub having a journal bearing 62 therein and in which is rotatively disposed a drive bushing 64 having an inner bore 66 in which crank pin 32 is drivingly disposed. Crank pin 32 has a flat on one surface which drivingly engages a flat surface (not shown) formed in a portion of bore 66 to provide a radially compliant driving arrangement, such as shown in assignee's U.S. Pat. No. 4,877,382, the disclosure of which is hereby incorporated herein by reference. An Oldham coupling 68 is also provided positioned between orbiting scroll member 56 and bearing housing 24 and keyed to orbiting scroll member 56 and a non-orbiting scroll member 70 to prevent rotational movement of orbiting scroll member 56 . [0046] Non-orbiting scroll member 70 is also provided having a wrap 72 extending downwardly from an end plate 74 which is positioned in meshing engagement with wrap 58 of orbiting scroll member 56 . Non-orbiting scroll member 70 has a centrally disposed discharge passage 76 which communicates with an upwardly open recess 78 which in turn is in fluid communication with a discharge muffler chamber 80 defined by cap 14 and partition 22 . A first and a second annular recess 82 and 84 are also formed in non-orbiting scroll member 70 . Recesses 82 and 84 define axial pressure biasing chambers which receive pressurized fluid being compressed by wraps 58 and 72 so as to exert an axial biasing force on non-orbiting scroll member 70 to thereby urge the tips of respective wraps 58 , 72 into sealing engagement with the opposed end plate surfaces of end plates 74 and 60 , respectively. Outermost recess 82 receives pressurized fluid through a passage 86 and innermost recess 84 receives pressurized fluid through a plurality of passages 88 . Disposed between non-orbiting scroll member 70 and partition 22 are three annular pressure actuated flip seals 90 , 92 and 94 . Seals 90 and 92 isolate outermost recess 82 from a suction chamber 96 and innermost recess 84 while seals 92 and 94 isolate innermost recess 84 from outermost recess 82 and discharge chamber 80 . [0047] Muffler plate 22 includes a centrally located discharge port 100 which receives compressed refrigerant from recess 78 in non-orbiting scroll member 70 . When compressor 10 is operating at its full capacity or at its highest design pressure ratio, port 100 discharges compressed refrigerant to discharge chamber 80 . Muffler plate 22 also includes a plurality of discharge passages 102 located radially outward from discharge port 100 . Passages 102 are circumferentially spaced at a radial distance where they are located above innermost recess 84 . When compressor 10 is operating at its reduced capacity or at its lower design pressure ratio, passages 102 discharge compressed refrigerant to discharge chamber 80 . The flow of refrigerant through passages 102 is controlled by a valve 104 mounted on partition 22 . A valve stop 106 positions and maintains valve 104 on muffler plate 22 such that it covers and closes passages 102 . [0048] Referring now to FIGS. 3 and 4, a temperature protection system 110 and a pressure relief system 112 are illustrated. Temperature protection system 110 comprises an axially extending passage 114 , a radially extending passage 116 , a bimetallic disc 118 and a retainer 120 . Axial passage 114 intersects with radial passage 116 to connect recess 84 with suction chamber 96 . Bi-metallic disc 118 is located within a circular bore 122 and it includes a centrally located indentation 124 which engages axial passage 114 to close passage 114 . Bi-metallic disc 118 is held in position within bore 122 by retainer 120 . When the temperature of refrigerant in recess 84 exceeds a predetermined temperature, bi-metallic disc 118 will snap open or move into a domed shape to space indentation 124 from passage 114 . Refrigerant will then flow from recess 84 through a plurality of holes 126 in disc 118 into passage 114 into passage 116 and into suction chamber 96 . The pressurized gas within recess 82 will vent to recess 84 due to the loss of sealing for annular seal 92 . [0049] When the pressurized gas within recess 84 is vented, annular seal 92 will lose sealing because it, like seals 90 and 94 , are energized in part by the pressure differential between adjacent recesses 82 and 84 . The loss of pressurized fluid in recess 84 will thus cause fluid to leak between recess 82 and recess 84 . This will result in the removal of the axial biasing force provided by pressurized fluid within recesses 82 and 84 which will in turn allow separation of the scroll wrap tips with the opposing end plate resulting in a leakage path between discharge chamber 80 and suction chamber 96 . This leakage path will tend to prevent the build up of excessive temperatures within compressor 10 . [0050] Pressure relief system 112 comprises an axially extending passage 128 , a radially extending passage 130 and a pressure relief valve assembly 132 . Axial passage 128 intersects with radial passage 130 to connect recess 84 with suction chamber 96 . Pressure relief valve assembly 132 is located within a circular bore 134 located at the outer end of passage 130 . Pressure relief valve assembly 132 is well known in the art and will therefore not be described in detail. When the pressure of refrigerant within recess 84 exceeds a predetermined pressure, pressure relief valve assembly 132 will open to allow fluid flow between recess 84 and suction chamber 96 . The venting of fluid pressure by valve assembly 132 will affect compressor 10 in the same manner described above for temperature protection system 110 . The leakage path which is created by valve assembly 132 will tend to prevent the build-up of excessive pressures within compressor 10 . The response of valve assembly 132 to excessive discharge pressures is improved if the compressed pocket that is in communication with recess 84 is exposed to discharge pressure for a portion of the crank cycle. This is the case if the length of the active scroll wraps 58 and 72 needed to compress between an upper design pressure ratio 140 and a lower design pressure 142 (FIG. 5) is less then 360°. [0051] Referring now to FIG. 5, a typical compressor operating envelope for an air conditioning application is illustrated. Also shown are the relative locations for upper design pressure ratio 140 and lower design pressure ratio 142 . Upper design pressure ratio 140 is chosen to optimize operation of compressor 10 at the motor low-voltage test point. When compressor 10 is operating at this point, the refrigerant being compressed by scroll members 56 and 70 enter discharge chamber 80 through discharge passage 76 , recess 78 and discharge port 100 . Discharge passages 102 are closed by valve 104 which is urged against partition 22 by the fluid pressure within discharge chamber 80 . Increasing the overall efficiency of compressor 10 at design pressure ratio 140 allows the design motor torque to be reduced which yields increased motor efficiency at the rating point. Lower design pressure ratio 142 is chosen to match the rating point for compressor 10 to further improve efficiency. [0052] Thus, if the operating point for compressor 10 is above lower design pressure ratio 142 , the gas within the scroll pockets is compressed along the full length of wraps 58 and 72 in the normal manner to be discharged through passage 76 , recess 78 and port 100 . If the operating point for compressor 10 is at or below lower design pressure ratio 142 , the gas within the scroll pockets is able to discharge through passages 102 by opening valve 104 before reaching the inner ends of scroll wraps 58 and 72 . This early discharging of the gas avoids losses due to compression ratio mismatch. [0053] Outermost recess 82 acts in a typical manner to offset a portion of the gas separating forces in the scroll compression pockets. The fluid pressure within recess 82 axially bias the vane tips of non-orbiting scroll member 70 into contact with end plate 60 of orbiting scroll member 56 and the vane tips of orbiting scroll member 56 into contact with end plate 74 of non-orbiting scroll member 70 . Innermost recess 84 acts in this typical manner at a reduced pressure when the operating condition of compressor 10 is below lower design pressure ratio 142 and at an increased pressure when the operating condition of compressor 10 is at or above lower design pressure ratio 142 . In this mode, recess 84 can be used to improve the axial pressure balancing scheme since it provides an additional opportunity to minimize the tip contact force. [0054] In order to minimize the re-expansion losses created by axial passages 88 and 102 used for early discharge end, the volume defined by innermost recess 84 should be held to a minimum. An alternative to this would be to incorporate a baffle plate 150 into recess 84 as shown in FIGS. 1 and 6. Baffle plate 150 controls the volume of gas that passes into recess 84 from the compression pockets. Baffle plate 150 operates similar to the way that valve plate 104 operates. Baffle plate 150 is constrained from angular motion but it is capable of axial motion within recess 84 . When baffle plate 150 is at the bottom of recess 84 in contact with non-orbiting scroll member 70 , the flow of gas into recess 84 is minimized. Only a very small bleed hole 152 connects the compression pocket with recess 84 . Bleed hole 152 is in line with one of the axial passages 88 . Thus, expansion losses are minimized. When baffle plate 150 is spaced from the bottom of recess 84 , sufficient gas flow for early discharging flows through a plurality of holes 154 offset in baffle plate 150 . Each of the plurality of holes 154 is in line with a respective passage 102 and not in line with any of passages 88 . When using baffle plate 150 and optimizing the response of pressure relief valve assembly 132 by having an active scroll length of 360° between ratios 140 and 142 as described above, the trade off for this increased response will be the possibility of the opening of baffle plate 150 . [0055] Referring now to FIG. 6, an enlarged section of recesses 78 and 84 of non-orbiting scroll member 70 is illustrated according to another embodiment of the present invention. In this embodiment, a discharge valve 160 is located within recess 78 . Discharge valve 160 includes a valve seat 162 , a valve plate 164 and a retainer 166 . [0056] Referring now to FIG. 7, an enlarged section of recesses 78 and 84 of non-orbiting scroll member 70 is illustrated according to another embodiment of the present invention. In this embodiment valve 104 and baffle plate 150 are connected by a plurality of connecting members 170 . Connecting members 170 require that valve 104 and baffle plate 150 move together. The benefit to connecting valve 104 and baffle plate 150 is to avoid any dynamic interaction between the two. [0057] Referring now to FIG. 8, an enlarged section of recesses 78 and 84 of non-orbiting scroll member 70 is illustrated according to another embodiment of the present invention. In this embodiment valve 104 and baffle plate 150 are replaced with a single unitary valve 104 ′. Using single unitary valve 104 ′ has the same advantages as those described for FIG. 7 in that dynamic interaction is avoided. [0058] Referring now to FIG. 9, an enlarged section of recesses 78 and 84 of a non-orbiting scroll member 270 is illustrated according to another embodiment of the present invention. Scroll member 270 is identical to scroll member 70 except that a pair of radial passages 302 replace the plurality of passages 102 through partition 22 . In addition, a curved flexible valve 304 located along the perimeter of recess 78 replaces valve 104 . Curved flexible valve 304 is a flexible cylinder which is designed to flex and thus to open radial passages 302 in a similar manner with the way that valve 104 opens passages 102 . The advantage to this design is that a standard partition 22 which does not include passages 102 can be utilized. While this embodiment discloses radial passage 302 and flexible valve 304 , it is within the scope of the present invention to eliminate passage 302 and valve 304 and design flip seal 94 to function as the valve between innermost recess 84 and discharge chamber 80 . Since flip 94 is a pressure actuated seal, the higher pressure within discharge chamber 80 over the pressure within recess 84 actuates flip seal 94 . Thus, if the pressure within recess 84 would exceed the pressure within discharge chamber 80 , flip seal 94 could be designed to open and allow the passage of the high pressure gas. [0059] Referring now to FIG. 10, an enlarged section of recesses 78 and 84 of a non-orbiting scroll member 370 is illustrated according to another embodiment of the present invention. Scroll member 370 is identical to scroll member 70 except that the pair of radial passages 402 replace the plurality of passages 102 through partition 22 . In addition, a valve 404 is biased against passages 402 by a retaining spring 406 . A valve guide 408 controls the movement of valves 404 . Valves 404 are designed to open radial passages 402 in a similar manner with the way that valve 104 opens passages 102 . The advantage to this design is again that a standard partition 22 which does not include passages 102 can be utilized. [0060] While not specifically illustrated, it is within the scope of the present invention to configure each of valves 404 such that they perform the function of both opening passages 402 and minimize the re-expansion losses created through passages 88 in a manner equivalent to that of baffle plate 150 . [0061] With reference to FIGS. 1, 2, 11 and 12 , flip seals 90 , 92 and 94 are each configured during installation as an annular L-shaped seal. Outer flip seal 90 is disposed within a groove 200 located within non-orbiting scroll member 70 . One leg of flip seal 90 extends into groove 200 while the other leg extends generally horizontal, as shown in FIGS. 1, 2 and 12 to provide sealing between non-orbiting scroll member 70 and muffler plate 22 . Flip seal 90 functions to isolate recess 82 from the suction area of compressor 10 . The initial forming diameter of flip seal 90 is less than the diameter of groove 200 such that the assembly of flip seal 90 into groove 200 requires stretching of flip seal 90 . Preferably, flip seal 90 is manufactured from a Teflon® material containing 10% glass when interfacing with steel components. [0062] Center flip seal 92 is disposed within a groove 204 located within non-orbiting scroll member 70 . One leg of flip seal 92 extends into groove 204 while the other leg extends generally horizontal, as shown in FIGS. 1, 2 and 12 to provide sealing between non-orbiting scroll member 70 and muffler plate 22 . Flip seal 92 functions to isolate recess 82 from the bottom of recess 84 . The initial forming diameter of flip seal 92 is less than the diameter of groove 204 such that the assembly of flip seal 92 into groove 204 requires stretching of flip seal 92 . Preferably, flip seal 92 is manufactured from a Teflon® material containing 10% glass when interfacing with steel components. [0063] Inner flip seal 94 is disposed within a groove 208 located within non-orbiting scroll member 70 . One leg of flip seal 94 extends into groove 208 while the other leg extends generally horizontal, as shown in FIGS. 1, 2 and 12 to provide sealing between non-orbiting scroll member 70 and muffler plate 22 . Flip seal 94 functions to isolate recess 84 from the discharge area of compressor 10 . The initial forming diameter area of flip seal 94 is less than the diameter of groove 208 such that the assembly of flip seal 94 into groove 208 requires stretching of flip seal 94 . Preferably, flip seal 94 is manufactured from a Teflon® material containing 10% glass when interfacing with steel components. [0064] Seals 90 , 92 and 94 therefore provide three distinct seals; namely, an inside diameter seal of seal 94 , an outside diameter seal of seal 90 , and a middle diameter seal of seal 92 . The sealing between muffler plate 22 and seal 94 isolates fluid under intermediate pressure in recess 84 from fluid under discharge pressure. The sealing between muffler plate 22 and seal 90 isolates fluid under intermediate pressure in recess 82 from fluid under suction pressure. The sealing between muffler plate 22 and seal 92 isolates fluid under intermediate pressure in recess 84 from fluid under a different intermediate pressure in recess 82 . Seals 90 , 92 and 94 are pressure activated seals as described below. [0065] Grooves 200 , 204 and 208 are all similar in shape. Groove 200 will be described below. It is to be understood that grooves 204 and 208 include the same features as groove 200 . Groove 200 includes a generally vertical outer wall 240 , a generally vertical inner wall 242 and an undercut portion 244 . The distance between walls 240 and 242 , the width of groove 200 , is designed to be slightly larger than the width of seal 90 . The purpose for this is to allow pressurized fluid from recess 82 into the area between seal 90 and wall 242 . The pressurized fluid within this area will react against seal 90 forcing it against wall 240 thus enhancing the sealing characteristics between wall 240 and seal 90 . Undercut 244 is positioned to lie underneath the generally horizontal portion of seal 90 as shown in FIG. 12. The purpose for undercut 244 is to allow pressurized fluid within recess 82 to act against the horizontal portion of seal 92 urging it against muffler plate 22 to enhance its sealing characteristics. Thus, the pressurized fluid within recess 82 reacts against the inner surface of seal 90 to pressure activate seal 90 . As stated above, grooves 204 and 208 are the same as groove 200 and therefore provide the same pressure activation for seals 92 and 94 . FIGS. 23 A- 23 H illustrate additional configurations for grooves 200 , 204 and 208 . [0066] The unique installed L-shaped configuration of seals 90 , 92 and 94 of the present invention are relatively simple in construction, easy to install and inspect, and effectively provide the complex sealing functions desired. The unique sealing system of the present invention comprises three flip seals 90 , 92 and 94 that are “stretched” into place and then pressure activated. The unique seal assembly of the present invention reduces overall manufacturing costs for the compressor, reduces the number of components for the seal assembly, improves durability by minimizing seal wear and provides room to increase the discharge muffler volume for improved damping of discharging pulse without increasing the overall size of the compressor. [0067] The seals of the present invention also provide a degree of relief during flooded starts. Seals 90 , 92 and 94 are designed to seal in only one direction. These seals can then be used to relieve high pressure fluid from the intermediate chambers or recesses 82 and 84 to the discharge chamber during flooded starts, thus reducing inter-scroll pressures and the resultant stress and noise. [0068] Referring now to FIG. 13, a groove 300 in accordance with another embodiment of the present invention is illustrated. Groove 300 includes an outwardly angled outer wall 340 , generally vertical inner wall 242 and undercut portion 244 . Thus, groove 300 is the same as groove 200 except that the outwardly angled outer wall 340 replaces generally vertical outer wall 240 . The function, operation and advantages of groove 300 and seal 90 are the same as groove 200 and seal 90 detailed above. The angling of the outer wall enhances the ability of the pressurized fluid within recess 82 to react against the inner surface of seal 90 to pressure activate seal 90 . It is to be understood that grooves 200 , 204 and 208 can each be configured the same as groove 300 . [0069] Referring now to FIG. 14, a seal groove 400 in accordance with another embodiment of the present invention is illustrated. Groove 400 includes outwardly angled outer wall 340 and a generally vertical inner wall 442 . Thus, groove 400 is the same as groove 300 except that undercut portion 244 has been removed. The function, operation and advantages of groove 300 and seal 90 are the same as grooves 200 and 300 and seal 90 as detailed above. The elimination of undercut portion 244 is made possible by the incorporation of a wave spring 450 underneath seal 90 . Wave spring 450 biases the horizontal portion of seal 90 upward toward muffler plate 22 to provide a passage for the pressurized gas within recess 82 to react against the inner surface of seal 90 to pressure activate seal 90 . It is to be understood that grooves 200 , 204 and 208 can each be configured the same as groove 400 . [0070] Referring now to FIG. 15, a sealing system 420 in accordance with another embodiment of the present invention is illustrated. Sealing system 420 seals fluid pressure between a partition 422 and a non-orbiting scroll member 470 . Non-orbiting scroll member 470 is designed to replace non-orbiting scroll member 70 or any other of the non-orbiting scroll members described. In a similar manner, partition 422 is designed to replace partition 22 in the above-described compressors. [0071] Non-orbiting scroll member 470 includes scroll wrap 72 and it defines an annular recess 484 , an outer seal groove 486 and an inner seal groove 488 . Annular recess 484 is located between outer seal groove 486 and inner seal groove 488 and it is provided compressed fluid through fluid passage 88 which opens to a fluid pocket defined by non-orbiting scroll wrap 72 of non-orbiting scroll member 470 and orbiting scroll wrap 58 of orbiting scroll member 56 . The pressurized fluid provided through fluid passage 88 is at a pressure which is intermediate or in between the suction pressure and the discharge pressure of the compressor. The fluid pressure within annular recess 484 biases non-orbiting scroll member 470 towards orbiting scroll member 56 to enhance the tip sealing characteristics between the two scroll members. [0072] A flip seal 490 is disposed within outer seal groove 486 and a flip seal 492 is disposed within inner seal groove 488 . Flip seal 490 sealingly engages non-orbiting scroll member 470 and partition 422 to isolate annular recess 484 from suction pressure. Flip seal 492 sealing engages non-orbiting scroll member 470 and partition 422 to isolate annular recess 484 from discharge pressure. While not illustrated in FIG. 15, non-orbiting scroll member 470 can include temperature protection system 110 . Also, while not illustrated, non-orbiting scroll member 470 can also include pressure relief system 112 if desired. [0073] Referring now to FIG. 16, a sealing system 520 in accordance with another embodiment of the present invention is illustrated. Sealing system 520 seals fluid pressure between a partition 522 and a non-orbiting scroll member 570 . Non-orbiting scroll member 570 is designed to replace non-orbiting scroll member 70 or any other of the non-orbiting scroll members described. In a similar manner, partition 522 is designed to replace partition 22 or any of the other of the previously described partitions. [0074] Non-orbiting scroll member 570 includes scroll wrap 72 and it defines an annular recess 584 , an outer seal groove 586 and an inner seal groove 588 . Annular recess 584 is located between outer seal groove 586 and inner seal groove 588 and it is provided with compressed fluid through fluid passage 88 which opens to a fluid pocket defined by non-orbiting scroll wrap 72 of non-orbiting scroll member 570 and orbiting scroll wrap 58 of orbiting scroll member 56 . The pressurized fluid provided through fluid passage 88 is at a pressure which is intermediate or in between the suction pressure and the discharge pressure of the compressor. The fluid pressure within annular recess 586 biases non-orbiting scroll member 570 towards orbiting scroll member 56 to enhance the tip scaling characteristics between the two scroll members. [0075] A flip seal 590 is disposed within outer seal groove 586 and a flip seal 592 is disposed within inner seal groove 588 . Flip seal 590 sealingly engages non-orbiting scroll member 570 and partition 522 to isolate annular recess 584 from suction pressure. Flip seal 592 sealingly engages non-orbiting scroll member 570 and partition 522 to isolate annular recess 584 from discharge pressure. While not specifically illustrated in FIG. 16, non-orbiting scroll member 570 can include temperature protection system 110 . Also, while not illustrated, non-orbiting scroll member 570 can also include pressure relief system 112 if desired. [0076] Referring now to FIG. 17, a sealing system 620 in accordance with another embodiment of the present invention is illustrated. Sealing system 620 seals fluid pressure between a partition 622 and a non-orbiting scroll member 670 . Non-orbiting scroll member 670 is designed to replace non-orbiting scroll member 70 or any other of the non-orbiting scroll members described. In a similar manner, partition 622 is designed to replace partition 22 or any other of the previously described partitions. [0077] Non-orbiting scroll member 670 includes scroll wrap 72 and it defines an annular recess 684 . Partition 622 defines an outer seal groove 686 and an inner seal groove 688 . Annular recess 684 is located between outer seal groove 686 and inner seal groove 688 and it is provided compressed fluid through fluid passage 88 which opens to a fluid pocket defined by non-orbiting scroll wrap 72 of non-orbiting scroll member 670 and orbiting scroll wrap 58 of orbiting scroll member 56 . The pressurized fluid provided through fluid passage 88 is at a pressure which is intermediate or in between the suction pressure and the discharge pressure of the compressor. The fluid pressure within recess 684 biases non-orbiting scroll member 270 towards orbiting scroll member 56 to enhance the tip sealing characteristics between the two scroll members. [0078] A flip seal 690 is disposed within outer seal groove 686 and a flip seal 692 is disposed within inner seal groove 608 . Flip seal 690 sealingly engages non-orbiting scroll member 670 and partition 622 to isolate annular recess 684 from suction pressure. Flip seal 692 sealing engages non-orbiting scroll member 670 and partition 622 to isolate annular recess 684 from discharge pressure. While not specifically illustrated in FIG. 17, non-orbiting scroll member 670 can include temperature protection system 110 . Also, while not illustrated, non-orbiting scroll member 670 can also include pressure relief system 112 if desired. [0079] Referring now to FIG. 18, a sealing system 720 in accordance with another embodiment of the present invention is illustrated. Sealing system 7020 seals fluid pressure between a cap 714 and a non-orbiting scroll member 770 . A discharge fitting 718 and a suction fitting 722 are secured to cap 714 to provide for a direct discharge scroll compressor and for providing for the return of the decompressed gas to the compressor. Non-orbiting scroll member 770 is designed to replace non-orbiting scroll member 70 or any other of the non-orbiting scroll members described. As shown in FIG. 18, a partition between the suction pressure zone and the discharge pressure zone of the compressor has been eliminated due to sealing system 720 being disposed between cap 714 and non-orbiting scroll member 770 . [0080] Non-orbiting scroll member 770 includes scroll wrap 72 and it defines an annular recess 784 , an outer seal groove 786 and an inner seal groove 788 . A passage 782 interconnects annular recess 784 with outer seal groove 786 . Annular chamber 784 is located between outer seal groove 786 and inner seal groove 788 and it is provided compressed fluid through fluid passage 88 which opens to a fluid pocket defined by non-orbiting scroll wrap 72 of non-orbiting scroll member 770 and orbiting scroll wrap 58 of orbiting scroll member 56 . The pressurized fluid provided through fluid passage 88 is at a pressure which is intermediate or in between the suction pressure and the discharge pressure of the compressor. The fluid pressure within annular chamber 784 biases non-orbiting scroll member 770 towards orbiting scroll member 56 to enhance the tip sealing characteristics between the two scroll members. [0081] A flip seal 790 is disposed within outer seal groove 786 and a flip seal 792 is disposed within inner seal groove 788 . Flip seal 790 sealing engages non-orbiting scroll member 770 and cap 714 to isolate annular recesses 784 from suction pressure. Flip seal 792 sealingly engages non-orbiting scroll member 770 and cap 714 to isolate annular recesses 784 from discharge pressure. While not illustrated in FIG. 18, non-orbiting scroll member 770 can include temperature protection system 110 and/or pressure relief system 112 if desired. [0082] Referring now to FIG. 19, the compressor illustrated in FIG. 18 is shown incorporating a vapor injection system 730 . Vapor injection system 730 includes an injection pipe 732 which extends through cap 714 and is in communication with a vapor injection passage 734 extending through non-orbiting scroll member 770 . A flat top seal 736 seals the interface between injection pipe 732 and non-orbiting scroll member 770 as well as providing a seal between vapor injection passage 734 and annular recess 786 . Vapor injection passage 734 is in communication with one or more of the fluid pockets formed by scroll wraps 72 and 58 of scroll members 770 and 56 , respectively. Vapor injection system 730 further comprises a valve 738 , which is preferably a solenoid valve, and a connection pipe 740 which leads to a source of compressed vapor. When additional capacity for the compressor is required, vapor injection system 730 can be activated to inject pressurized vapor into the compressor as is well known in the art. Vapor injection systems are well known in the art so a full discuss of the system will not be included herein. By operating vapor injection system in a pulse width modulation mode, the capacity of the compressor can be increased incrementally between its full capacity and a capacity above its full capacity as provided by vapor injection system 730 . [0083] Referring now to FIG. 20, a sealing system 820 in accordance with the present invention is illustrated. Sealing system 820 seals fluid pressure between a partition 822 and a non-orbiting scroll member 870 . Non-orbiting scroll member 870 is designed to replace non-orbiting scroll member 70 or any other of the non-orbiting scroll members described. Partition 822 is designed to replace partition member 22 or any other of the partitions described. [0084] Non-orbiting scroll member 870 includes scroll wrap 72 and it defines an annular chamber 884 . Partition 822 defines an outer seal groove 886 and an inner seal groove 888 . Annular chamber 884 is located between outer seal groove 886 and inner seal groove 888 and it is provided compressed fluid through fluid passage 88 which opens to a fluid pocket defined by non-orbiting scroll wrap 72 of non-orbiting scroll member 870 and orbiting scroll wrap 58 of orbiting scroll member 56 . The pressurized fluid provided through fluid passage 88 is at a pressure which is intermediate or in between the suction pressure and the discharge pressure of the compressor. The fluid pressure within annular chamber 884 biases non-orbiting scroll member 870 towards orbiting scroll member 56 to enhance the tip sealing characteristics between the two scroll members. [0085] A flip seal 890 is disposed within outer seal groove 886 and a flip seal 892 is disposed within inner seal groove 888 . Flip seal 890 engages non-orbiting scroll member 870 and partition 822 to isolate annular chamber 884 from suction pressure. Flip seal 892 sealingly engages non-orbiting scroll member 870 and partition 822 to isolate annular chamber 884 from discharge pressure. While not illustrated in FIG. 20, non-orbiting scroll member 870 can include temperature protection system 110 . Also, while not illustrated, non-orbiting scroll member 870 can also include pressure relief system 112 if desired. [0086] Referring now to FIG. 21, a sealing system 920 in accordance with another embodiment of the present invention is illustrated. Sealing system 920 seals fluid pressure between a cap 914 and a non-orbiting scroll member 970 . A discharge fitting 918 is secured to cap 914 to provide for a direct discharge scroll compressor. Non-orbiting scroll member 970 is designed to replace non-orbiting scroll member 70 or any other of the non-orbiting scroll members described. As shown in FIG. 21, a partition between the suction pressure zone and the discharge pressure zone of the compressor has been eliminated due to sealing system 920 being disposed between cap 914 and non-orbiting scroll member 970 . [0087] Non-orbiting scroll member 970 includes scroll wrap 72 and it defines an annular recess 984 . Disposed within annular recess 984 is a floating seal 950 . The basic concept for floating seal 950 with axial pressure biasing is disclosed in much greater detail in Assignee's U.S. Pat. No. 4,877,382, the disclosure of which is incorporated herein by reference. Floating seal 950 comprises a base ring 952 , a sealing ring 954 , an outer flip seal 990 and an inner flip seal 992 . Flip seals 990 and 992 are sandwiched between rings 952 and 954 and are held in place by a plurality of posts 956 which are an integral part of base ring 952 . Sealing ring 954 includes a plurality of holes 958 which correspond with the plurality of posts 956 . Once base ring 952 , seals 990 and 992 and sealing ring 954 are assembled, posts 956 are mushroomed over to complete the assembly of floating seal 950 . While seals 990 and 992 are described as being separate components, it is within the scope of the present invention to have a single piece component provide seals 990 and 992 with this single piece component including a plurality of holes which correspond with the plurality of posts 956 . [0088] Annular recess 984 is provided compressed fluid through fluid passage 88 which opens to a fluid pocket defined by non-orbiting scroll wrap 72 of non-orbiting scroll member 970 and orbiting scroll wrap 58 of orbiting scroll member 56 . The pressurized fluid provided through fluid passage 88 is at a pressure which is intermediate or in between the suction pressure and the discharge pressure of the compressor. The fluid pressure within annular recess 984 biases non-orbiting scroll member 970 towards orbiting scroll member 56 to enhance the tip sealing characteristics between the two scroll members. In addition, fluid pressure within annular recess 984 biases floating seal member 950 against upper cap 914 of the compressor. Sealing ring 954 engages upper cap 914 to seal the suction pressure area of the compressor from the discharge area of the compressor. Flip seal 990 sealingly engages non-orbiting scroll member 970 and rings 952 and 954 to isolate annular recess 984 from suction pressure. Flip seal 992 sealingly engages non-orbiting scroll member 970 and rings 952 and 954 to isolate annular recess 984 from discharge pressure. While not specifically illustrated in FIG. 21, non-orbiting scroll member 970 can include temperature protection system 110 and/or pressure relief system 112 . [0089] Referring now to FIG. 22, the compressor illustrated in FIG. 21 is shown incorporating a vapor injection system 930 . Vapor injection system 930 comprises a coupling 932 and an injection pipe 934 . Injection pipe 934 extends through cap 914 and is in communication with a vapor injection passage 936 extending through coupling 932 . A flip seal 938 seals the interface between coupling 932 and injection pipe 934 . Vapor injection passage 936 is in communication with a vapor injection passage 940 which extends through non-orbiting scroll member 970 to open into one or more of the fluid pockets formed by scroll wraps 72 and 58 of scroll members 970 and 56 , respectively. Vapor injection system 930 further comprises a valve 942 which is preferably a solenoid valve and a connection pipe 944 which leads to a source of compressed vapor. When additional capacity for the compressor is received, vapor injection system 930 can be activated to inject pressurized vapor into the compressor as is well known in the art. Vapor injection systems are well known in the art so a full discussion of the system will not be included herein. By operating vapor injection system 930 in a pulse width modulation mode, the capacity of the compressor can be increased incrementally between its full capacity and a capacity above its full capacity as provided by vapor injection system 930 . [0090] Referring now to FIGS. 23 A- 23 H, various configurations for the seal grooves described above are illustrated. FIG. 23A illustrates a seal groove 1100 having a rectangular configuration. FIG. 23B illustrates a seal groove 1110 having one side defining a straight portion 1112 and a tapered portion 1114 . This is the preferred groove geometry with the edge of the seal assembled within groove 1110 sealing against either one of portions 1112 or 1114 . The other side of groove 1110 is a straight wall. FIG. 23C illustrates a seal groove 1120 having one side defining a first tapered portion 1122 and a second tapered portion 1124 . The edge of the seal assembled within groove 1120 seals against either one of portions 1122 or 1124 . The other side of groove 1120 is a straight wall. [0091] [0091]FIG. 23D illustrates a seal groove 1130 having one side defining a reverse tapered wall 1132 . The edge of the seal assembled within groove 1130 seals against reverse tapered wall 1132 . The other side of groove 1130 is a straight wall. FIG. 23E illustrates a seal groove 1140 having one wall defining a first reverse tapered portion 1142 and a second reverse tapered portion 1144 . The edge of the seal assembled within groove 1140 seals against either one of portions 1142 or 1144 . The other side of groove 1140 is a straight wall. FIG. 23F illustrates a seal groove 1150 having one side defining a reverse tapered portion 1152 and a tapered portion 1154 . The edge of the seal assembled within groove 1150 seals against either one of portions 1152 or 1154 . The other side of groove 1150 is a straight wall. [0092] [0092]FIG. 23G illustrates a seal groove 1160 having one side defining a reverse tapered portion 1162 , a straight portion 1164 and a tapered portion 1166 . The edge of the seal assembled within groove 1160 seals against either one of portions 1162 , 1164 or 1166 . The other side of seal groove 1160 is a straight wall. FIG. 23H illustrates a seal groove 1170 having one side defining a curved wall 1172 . The edge of the seal assembled within groove 1170 seals against curved wall 1172 . The other side of seal groove 1170 is straight. [0093] Referring now to FIGS. 24 and 25, flip seal 90 is illustrated. FIG. 24 illustrates flip seal 90 in an as molded condition. Flip seal 90 is molded preferably from a Teflon® material containing 10% when it is interfacing with a steel component. Flip seal 90 is molded in an annular shape as shown in FIG. 24 with a notch 98 extending into one surface thereof. Notch 98 facilitates the bending of flip seal 90 into its L-shaped configuration as shown in FIG. 25. While FIGS. 24 and 25 illustrate flat top seal 90 , it is to be understood that flip seals 92 , 94 , 490 , 492 , 590 , 592 , 690 , 692 , 790 , 792 , 890 , 892 , 990 and 992 are all manufactured with notch 98 . [0094] While not specifically illustrated, vapor injection systems 730 and 930 can be designed to provide for delayed suction closing instead of vapor injection. When designed for delayed suction closing, system 730 and 930 would extend between one of the closed pockets defined by the scroll wraps and the suction area of the compressor. The delayed suction closing systems provide for capacity modulation as is well known in the art and can also be operated in a pulse width modulation manner. In addition, the vapor injection system illustrated in FIGS. 19 and 22 can be incorporated into any of the embodiments of the invention illustrated. [0095] While the above detailed description describes the preferred embodiment of the present invention, it should be understood that the present invention is susceptible to modification, variation and alteration without deviating from the scope and fair meaning of the subjoined claims.

The present invention provides the art with a scroll machine which has a plurality of built-in volume ratios along with their respective design pressure ratios. The incorporation of more than one built-in volume ratio allows a single compressor to be optimized for more than one operating condition. The operating envelope for the compressor will determine which of the various built-in volume ratios is going to be selected. Each volume ratio includes a discharge passage extending between one of the pockets of the scroll machine and the discharge chamber. All but the highest volume ration utilize a valve controlling the flow through the discharge passage.

[0001] The present disclosure relates to the subject matter disclosed in German patent application No. 10 2007 015 154.5 of Mar. 22, 2007, which is incorporated herein by reference in its entirety and for all purposes. BACKGROUND OF THE INVENTION [0002] The present invention relates to a holding device for an implant, comprising a first connecting device for releasably connecting the holding device and the implant. [0003] The present invention also relates to a storage unit for accommodating and/or securing at least one holding device for an implant in place, wherein the holding device comprises a first connecting device for releasably connecting the holding device and the implant. [0004] A holding device of the type described at the outset is known, for example, from U.S. Pat. No. 6,929,646 B2. This holding device has an elongated handle portion, with the aid of which an implant connected to the handle portion can be brought into a desired implanting position and location relative to a body part to be operated. After the implant has been attached to the body part, the handle portion can be separated from the implant. [0005] It has been shown that the organization and handling of, in particular, very small implants is a problem. These implants differ from one another, at times, only very slightly but must be made available in numerous variations for a specific operation so that a surgeon can decide during the course of an operation which of the implants altogether available should be used. In some countries it is, in addition, necessary to document exactly what and how many implants have been used during the course of an operation. [0006] It would, therefore, be desirable to make a holding device and a storage unit of the type described at the outset available, with which very small implants, in particular, are easy to handle. SUMMARY OF THE INVENTION [0007] In the case of a holding device of the type described at the outset, it is suggested that the holding device have a second connecting device for releasably connecting the holding device and a storage unit. The holding device therefore makes it possible, with the aid of a first connecting device, to secure an implant or several implants releasably in place on the holding device. With the aid of the second connecting device of the holding device, this can be releasably connected to a storage unit. The holding device of a further development enables a separate holding device to be made available for each implant or for a group of implants so that each implant or each group of implants can be handled more easily with the aid of the associated holding device. The holding devices may be connected to the storage unit such that the implants can be clearly arranged and can be handled together with the aid of the storage unit. [0008] The first connecting device and the second connecting device can preferably be actuated independently of one another. As a result, an implant can be connected to the holding device with the aid of the first connecting device and be released from the holding device in that the first connecting device is actuated. This actuation is independent of whether the holding device is connected to the storage unit with the aid of the second connecting device or is released from it. In a corresponding manner, the second connecting device can be actuated in order to connect the holding device to the storage unit or release the holding device from the storage unit without this having any influence on the first connecting device and, therefore, on the connection between an implant and the holding device. [0009] The first connecting device can preferably be transferred from a first connecting position, in which an implant can be or is connected to the holding device, into a first release position, in which the holding device releases the implant. As a result, the implant can be fixed reliably on the holding device in the first connecting position of the first connecting device and be removed from the holding device in a simple manner in the first release position of the first connecting device. [0010] The first connecting device is preferably designed in such a manner that a first releasing force is required to transfer the first connecting device from the first connecting position into the first release position. The first releasing force defines the resistance which must be overcome for separation of the implant from the holding device. It is recommended that a releasing force be provided which is so great that an implant cannot be unintentionally detached from the holding device, for example, when the holding device is subject to slight shaking during transport. On the other hand, the first releasing force should be small enough for an implant to be releasable from the holding device manually or with the aid of a removing tool. [0011] The holding device preferably comprises a first restoring device which transfers the first connecting device from the first release position into the first connecting position. A preferential position of the first connecting device can be defined with the aid of the first restoring device and this corresponds to the first connecting position. This preferential position can be taken up independently of whether an implant is held in the holding device or not. [0012] It is favorable when the second connecting device can be transferred from a second connecting position, in which the holding device can be or is connected to the storage unit, into a second release position, in which the holding device can be released from the storage unit. In this way, the holding device can be secured reliably on the storage unit in the second connecting position of the second connecting device and so the holding device itself does not have to be handled but rather it can be handled with the aid of the storage unit. The holding device can be released from the storage unit in the second release position of the second connecting device so that the holding device can be handled independently of the storage unit. [0013] The second connecting device is preferably designed in such a manner that a second releasing force is necessary to transfer the second connecting device from the second connecting position into the second release position. This second releasing force should be great enough to avoid any unintentional release of the holding device from the storage unit. The second releasing force should, on the other hand, be small enough to be able to remove the holding device from the storage unit preferably without the aid of tools. [0014] In addition, it is preferred when the holding device comprises a second restoring device which transfers the second connecting device from the second release position into the second connecting position. A preferential position of the second connecting device can be defined with the aid of the second restoring device and this corresponds to the second connecting position. In this respect, a transfer into this preferential position can be carried out independently of whether the holding device is connected to the storage unit or not. [0015] It is particularly preferred when the first releasing force and the second releasing force differ from one another according to amount and/or direction. As a result, any unintentional, simultaneous actuation of the first connecting device and the second connecting device can be avoided. It is, therefore, ensured that when the first releasing force is applied only the first connecting device is brought from the first connecting position into the first release position without this having any influence on the state of the second connecting device. In a corresponding manner, when the second releasing force is applied this causes a transfer of the second connecting device from the second connecting position into the second release position without this influencing the state of the first connecting device. [0016] It is particularly preferred when the first releasing force and the second releasing force are linearly independent of one another. This makes it possible to decide, by selecting the corresponding release direction, whether the first connecting device is intended to be brought from the first connecting position into the first release position or whether the second connecting device is intended to be brought from the second connecting position into the second release position. As a result of the first and second release directions being linearly independent, it is possible to rule out that either of the two connecting devices will be brought from its connecting position into its release position in an unintentional manner. This applies irrespective of whether the first releasing force is smaller, the same as or greater than the second releasing force. [0017] In addition, it is preferred when the first releasing force is smaller than the second releasing force. This makes it possible to adjust the releasing forces such that even when the releasing forces are intended to be oriented in the same direction the first connecting device will be brought, first of all, from the first connecting position into the first release position and then the second connecting device will be brought from the second connecting position into the second release position. [0018] The first connecting device is preferably designed in such a manner that the implant can be handled in a first handling direction during movement from a first holding position, in which the implant is connected to the holding device, into a first release position, in which the implant is released from the holding device. With the handling direction it is possible to determine the direction, in which a surgeon must handle the implant in order to separate it from the holding device. [0019] Furthermore, the second connecting device is preferably designed in such a manner that the holding device can be handled in a second handling direction during movement from a second holding position, in which the holding device is connected to the storage unit, into a second release position, in which the holding device is released from the storage unit. With the aid of the second handling direction it is possible to define the direction, in which the holding device must be handled in order to separate it from the storage unit. [0020] It is particularly preferred when the first handling direction and the second handling direction are linearly independent of one another. When a surgeon releases an implant from the holding device in accordance with the first handling direction, any release of the holding device at the same time from the storage unit is precluded as a result of the linear independence of the handling directions. It is ensured in a corresponding manner that when the second handling direction is chosen to release the holding device from the storage unit an implant possibly connected to the holding device will not be released from the holding device. [0021] It is particularly preferred when the first handling direction and the second handling direction are at right angles or essentially at right angles to one another. This makes a particularly simple handling of the implant, the holding device and the storage unit possible, with which any unintentional release of the implant from the holding device and any unintentional release of the holding device from the storage unit is precluded. [0022] The holding device preferably defines a holding axis which predetermines the position and/or the location of the implant when it is connected to the holding device. In this way, it is possible to define an absolute spatial position and/or spatial location of an implant when the holding device is connected to a storage unit. [0023] It is particularly preferred when the holding axis and the first handling direction are at right angles or essentially at right angles to one another. This makes a particularly simple and gentle transfer of the implant from the first holding position into the first release position possible. [0024] It is favorable when the holding axis and the second handling direction are parallel or essentially parallel to one another. This makes a space-saving arrangement of the implant on the holding device and of the holding device on the storage unit possible. [0025] The first connecting device preferably comprises at least one holding element which is designed to connect the implant to the holding device in the first connecting position of the first connecting device. Such a holding element can make only a one-time transfer of the first connecting device from the first connecting position into the first release position possible. Such a holding element can also make a change between the first connecting position and the first release position possible many times. [0026] It is favorable when the at least one holding element is tongue-shaped. This makes an elastic movement of the holding element between the first connecting position and the first release position possible. [0027] In addition or optionally, the at least one holding element can also be in the shape of a circular segment. As a result of this, implants, which have implant sections which are shaped in accordance with the circular segment shape of a holding element, may be connected to the holding device in a particularly reliable manner. A holding element in the shape of a circular segment can, in addition and where applicable, prevent any release of the implant from the holding device in a direction deviating from the first handling direction. [0028] It is preferable when the at least one holding element can be moved and/or deformed within a holding plane. As a result of the movability and/or deformability of the at least one holding element within the holding plane, the amount of the first releasing force which is necessary for the transfer of the first connecting device from the first connecting position into the first release position can be defined in a particularly exact manner. [0029] The holding plane is preferably at right angles or essentially at right angles to the holding axis. This makes it possible, in particular, in the case of an essentially elongated implant, for example, a bone screw to release this from the holding device in a first handling direction which is at right angles to the holding axis. As a result of this, it is possible for the implant and the holding device to be subjected to only a minimal frictional contact during transfer of the implant from the first holding position into the first release position. [0030] It is favorable when the first connecting device has at least two holding elements. This makes it possible to introduce the first releasing force, which is required for transfer of the first connecting device from the first connecting position into the first release position, into at least two holding elements which are moved and/or deformed during the specified transfer. In this way, the mechanical load on the individual holding elements can be minimized. [0031] The at least two holding elements can preferably be moved in opening directions opposite to one another in order to transfer the first connecting device from the first connecting position into the first release position. In this way, the first releasing force can be distributed uniformly onto the at least two holding elements. [0032] In addition, it is preferable when the at least two holding elements can be moved in closing directions opposite to one another in order to transfer the first connecting device from the first release position into the first connecting position. This makes a gentle and self-centering transfer of the implant from the first release position into the first holding position possible. [0033] It is particularly preferred when at least one holding element builds up a first restoring force, with which the first connecting device can be transferred back into the first connecting position, in order to form the first restoring device during transfer of the first connecting device from the first connecting position into the first release position. This can be ensured, for example, by selecting a corresponding material, for example, plastic so that the holding element is elastically deformable and can build up a first restoring force during deflection out of a basic position which corresponds to the first connecting position. As a result of this, a particularly simple construction of the first restoring device is ensured. [0034] It is favorable when the at least one holding element limits an implant receptacle for accommodating the implant. As a result, the holding element contributes to an exact positioning of an implant on the holding device. [0035] It is, in addition, favorable when the implant receptacle has an undercut. This makes a particularly reliable connection of the implant and the holding device possible. [0036] It is advantageous when the implant receptacle is fully enclosed on its circumferential side. This makes a particularly reliable fixing of the implant to the holding device possible. [0037] It is favorable when the first connecting device comprises at least one contact element which can abut on the implant in a tensioned manner in the first connecting position of the first connecting device. It is possible in a particularly simple manner with such a contact element for an implant to be secured in place on the holding device free from clearance without the first connecting device of the holding device needing to meet high tolerance requirements. [0038] The contact segment advantageously limits the implant receptacle. As a result of this, a compact holding device can be created which makes a clearance-free connection of the holding device and implant possible. [0039] It is advantageous when the at least one contact element is in the shape of a circular segment. Such a contact element may abut on a curved implant section particularly well, providing contact over a large surface area. [0040] It is particularly preferred when the holding device has an indicating device which indicates an at least one-time transfer of the first connecting device from the first connecting position into the first release position. Such an indicating device makes it possible to ascertain without any doubt that an implant was connected to the holding device and has been released from the holding device. It can be concluded from this that this implant has been used during the course of an operation. This implant can be allocated with the aid of that holding device, the indicating device of which indicates the transfer of the first connecting device from the first connecting position into the first release position. It is understood that the indicating device described can also be provided in the case of holding devices which have only a first connecting device for releasably connecting the holding device and an implant and no second connecting device for releasably connecting the holding device and a storage unit. [0041] The indicating device preferably comprises at least one indicating element which can be destroyed and/or plastically deformed during transfer of the first connecting device from the first connecting position into the first release position. This makes a particularly simple configuration of the indicating device possible. [0042] It is preferred when the indicating device has at least one connecting section for the connection of at least two indicating elements and/or for the connection of the at least one indicating element to an additional part of the holding device, wherein the connecting section can be severed during transfer of the first connecting device from the first connecting position into the first release position. This makes a particularly simple construction of the indicating device possible. The connecting section can comprise, in particular, a predetermined breaking point or be formed by a predetermined breaking point. [0043] It is favorable when the at least one indicating element is of a tape-like shape. This makes destruction and/or plastic deformation of the indicating element possible with the aid of relatively small destruction and/or deforming forces. [0044] It is advantageous when the at least one indicating element has element sections which are movable relative to one another and extend in planes angled in relation to one another. In this way, the triggering force required for triggering the indicating device can be adjusted particularly well. [0045] The at least one indicating element is favorably formed by a holding element. This makes a particularly simple construction of the holding device possible. In addition, it is ensured in a particularly reliable manner that the indicating device is also triggered when the first releasing force is applied in order to transfer the first connecting device from the first connecting position into the first release position. [0046] It is favorable when the holding device comprises a plate-like basic member. The basic member makes a particularly compact configuration of the holding device possible. [0047] It is preferred when the basic member extends in the holding plane. This makes a space-saving arrangement of the holding elements on the basic member possible. [0048] In addition, it is preferred when the basic member extends at right angles or essentially at right angles to the holding axis. This makes a space-saving arrangement of an implant on the holding device possible as well as a space-saving arrangement of the holding device on the storage unit. [0049] It is favorable when the at least one holding element and/or the at least one contact element and/or the at least one indicating element is or are arranged on the basic member. As a result of this, a particularly compact holding device can be created. [0050] The at least one holding element and/or the at least one contact element and/or the at least one indicating element is or are preferably designed in one piece with the basic member. This makes a particularly inexpensive production of the holding device possible. [0051] The holding device preferably comprises a data storage device for storing implant data. This makes a clear allocation of an implant connectable to the holding device and of the holding device possible. The implant data can relate, for example, to a producer, an article number, a batch number and/or to other properties of the implant. By reading the data storage device it is possible to be able to trace the implant data even when the implant has already been detached from the holding device. This makes it easier to trace which implant has been used during the course of an operation. [0052] It is favorable when the data storage device is connected non-detachably to the holding device. This makes the allocation of the implant data to an implant connected to the holding device or detached from the holding device easier. [0053] It is advantageous when the data storage device is writable several times. This makes it possible for the holding device to be used for different implants or for a group of different implants. [0054] It is particularly preferred when the data storage device is designed to display the implant data in the form of an optical data storage device. This makes an optical identification of very small implants, in particular, possible which have, where applicable, no surface area which is large enough to display implant data. [0055] It is favorable when the implant data are present in an alphanumeric form, as a barcode and/or as a matrix code. As a result, the implant data can be read directly without the aid of additional devices and/or can be detected easily, for example, with the aid of a scanner. [0056] It is particularly preferred when the data storage device comprises a visible surface for the display of the implant data. This makes simple reading or scanning of the implant data possible. [0057] It is particularly preferred when the visible surface is formed on the basic member and so the construction of the holding device is simplified further. [0058] It is favorable when the implant data are designed to be in one piece with the holding device. As a result of this, a data storage device need not be made available separately. When the holding device is produced, for example, in an injection molding process, the implant data can be provided during the same production procedure as a result of corresponding configuration of the injection mold. [0059] It is advantageous when the data storage device is designed in the form of an electronic data storage device. Such a data storage device makes it possible to store very extensive implant data, as well. [0060] It is favorable when the data storage device comprises at least one RFID element. Such an element may be integrated inexpensively into the holding device or arranged on it, for example, by way of injection into a plastic material. In addition, an RFID element can be read without contact with the aid of a suitable reading device for reading the implant data. [0061] It is favorable when the second connecting device comprises at least one connecting element which is designed to connect the holding device to the storage unit in the second connecting position of the second connecting device. The holding device can be connected reliably to the storage unit and easily detached from the storage unit with the aid of the at least one connecting element. [0062] It is particularly preferred when the at least one connecting element comprises at least one snap-in element for forming a snap-in connection or is designed as a snap-in element, wherein the snap-in element is or can be brought into engagement interlockingly with the storage unit in the second connecting position of the second connecting device. Such a snap-in element makes a particularly reliable connection of the holding device and the storage unit possible. In addition, the transfer of the second connecting device from the second release position into the second connecting position can take place at the same time as a corresponding snap-in procedure of the snap-in element, whereby a good acoustic and/or optical indication conveys to an operator the fact that the second connecting device has reached its second connecting position. [0063] The at least one connecting element can preferably be moved and/or deformed within a plane of connection. In this way, a second releasing force, which is possibly required for transfer of the second connecting device from the second connecting position into the second release position, can be defined exactly with respect to amount and/or direction. [0064] The plane of connection is preferably parallel or essentially parallel to the holding axis of the implant. This makes a particularly simple construction of the second connecting device possible. [0065] In addition, it is advantageous when the second connecting device has at least two connecting elements. As a result of this, the second releasing force, which is possibly required for transfer of the second connecting device from the second connecting position into the second release position, can be introduced into several connecting elements and so the mechanical load on the individual connecting elements is minimized. [0066] The at least two connecting elements can preferably be moved in opening directions opposite to one another in order to transfer the second connecting device from the second connecting position into the second release position. This makes a comfortable handling of the holding device possible during the transfer of the second connecting device from the second connecting position into the second release position. [0067] Furthermore, the at least two connecting elements can preferably be moved in closing directions opposite to one another in order to transfer the second connecting device from the second release position into the second connecting position. This makes a comfortable handling of the holding device possible during the transfer of the second connecting device from the second release position into the second connecting position. [0068] It is favorable when the at least one connecting element builds up a second restoring force, with which the second connecting device can be transferred back into the second connecting position, for forming the second restoring device during transfer of the second connecting device from the second connecting position into the second release position. This makes a particularly simple construction of the second restoring device possible and this has the effect that the second connecting position of the second connecting device is the preferential position of the second connecting device. [0069] The at least one connecting element preferably limits an undercut area for the accommodation of a section of the storage unit in the second connecting position of the second connecting device. As a result of this, a particularly reliable connection between the holding device and the storage unit is ensured. [0070] It is preferred when the undercut area is limited by a contact surface of the basic member. In this way, an additional function associated with the second connecting device can be realized with the aid of the basic member. [0071] It is advantageous when the second connecting device comprises at least one essentially U-shaped material section which has two legs of the U which extend parallel or essentially parallel to the holding axis and are connected to one another via a base of the U. Such a material section makes a simple arrangement and/or realization of at least one connecting element possible. [0072] The holding axis is favorably arranged between two legs of the U. In this way, the implant can be protected from mechanical influences with the aid of the legs of the U when the implant is connected to the holding device. [0073] Furthermore, it can be advantageous when the holding axis is arranged outside a space formed between the legs of the U. This makes a particularly compact construction of the second connecting device possible. [0074] The second connecting device preferably comprises at least one actuating element for transferring the second connecting device from the second connecting position into the second release position. As a result of this, the holding device can be detached from the storage unit in a particularly simple manner. [0075] The at least one actuating element is preferably designed in the form of a gripping section. As a result of this, the second connecting device can be actuated manually. [0076] The at least one actuating element is arranged in an advantageous manner at a free end of a leg of the U. This makes a particularly simple transfer of the second connecting device from the second connecting position into the second release position possible. [0077] Furthermore, the at least one actuating element is preferably arranged on the basic member. As a result of this, the handling of the holding device is made easier. [0078] It is particularly preferred when at least one actuating element and at least one connecting element of the second connecting device are arranged on oppositely located sides of the basic member when looking along the holding axis of the implant. As a result of this, the second connecting device can be arranged relative to the storage unit in a space in the storage unit which is comparatively difficult to access but is well protected whereas the actuating element can be arranged on the oppositely located side of the basic member so as to be easily accessible. [0079] The holding device preferably comprises at least one securing device which prevents any implantation of the implant when the implant is connected to the holding device. This has the advantage that an implant which is connected to the holding device cannot be used unintentionally together with the holding device during the course of an operation on a body part to be operated. [0080] It is particularly favorable when the securing device comprises at least one securing section spaced from the holding axis. This makes it possible to protect a functional area of the implant, for example, a threaded section with the aid of the securing section so that this functional area cannot be brought into engagement with a body part to be operated. [0081] The securing section is preferably arranged at an angle relative to the basic member, in particular, at right angles or essentially at right angles. This makes a particularly compact construction of the holding device possible. It is, in addition, favorable when the securing section is essentially C-shaped in a cross section at right angles to the holding axis. This allows a functional area of an implant to be protected over a particularly large surface area. In addition, the securing device allows an extensive mechanical protection of the implant. [0082] In cross sections at right angles to the holding axis, the securing section is preferably larger in an area adjacent to the basic member than in an area removed from the basic member. This makes a particularly simple positioning of the holding device on the storage unit possible. In this respect, the holding device can be brought closer to the storage unit, first of all, with its area removed from the basic member and then be brought into abutment on the storage unit with the area adjacent to the basic member. [0083] The securing section is favorably formed by the U-shaped material section of the second connecting device. As a result of this, it is possible to dispense with a separate securing section. With the aid of the base of the U of this material section, an implant connected to the holding device can also be protected against mechanical influences in a direction parallel to the holding axis. [0084] It is favorable when the holding device has a guiding device, with which the holding device can be positioned relative to the storage unit. This makes the handling of the holding device easier when the holding device is connected to the storage unit. [0085] It is favorable when the guiding device has at least one guiding section which is designed to abut on a section of the storage unit. The guiding section can be formed by parts of the holding device which have already been described, for example, by parts of the second connecting device and/or by a securing section of the securing device. The guiding device can, however, also have in addition or optionally at least one separate guiding section. [0086] When the holding device comprises at least one implant, a structural module can be made available which can be connected to a storage unit. This structural module can be made available for an operation and sterilized again when not used and made available for the next operation. [0087] Furthermore, it is suggested for a storage unit of the type described at the outset that the holding device have a second connecting device for releasably connecting the holding device and the storage unit. The storage unit makes the handling of at least one holding device easier and, therefore, also the handling of a very small implant, in particular, which is possibly connected to the holding device. It is particularly advantageous when the storage unit allows accommodation and/or securing in place of several holding devices. [0088] It is preferred when the storage unit is designed for an orientation of at least two holding devices identical to one another. In this way, it is easier to find a specific holding device and, therefore, a specific implant. [0089] Furthermore, it is preferred when the storage unit is designed for an orderly arrangement of at least three holding devices. This also makes it easier to find specific holding devices and specific implants. [0090] A particularly neat arrangement of the holding device is achieved when the storage unit is designed for an arrangement of the holding devices in rows or columns. This makes a space-saving arrangement of several holding devices on the storage unit possible, in addition. [0091] It is favorable when the storage unit comprises at least one receptacle for accommodating and/or securing at least one holding device in place. The relative position and/or location of the holding device relative to the storage unit can be defined with the aid of the receptacle. [0092] It is particularly preferred when the at least one holding device can be inserted into the at least one receptacle at least in sections. As a result of this, the holding devices can be arranged on the storage unit in a space-saving manner and reliably connected to it. [0093] The storage unit preferably comprises a plate for forming or for the arrangement of the at least one receptacle. This makes an inexpensive production of the storage unit possible which can, in addition, be cleaned particularly well. [0094] The at least one receptacle is preferably limited by a section of the plate which can be connected to the second connecting device of the holding device. As a result of this, a storage unit which is constructed in a particularly simple manner can be created. [0095] It is favorable when the receptacle has a cross section which predetermines the rotary position of a holding device about its holding axis relative to the storage unit. In this way, the rotary position of the holding device can be predetermined and so the ease, with which this holding device and, therefore, a specific implant can be found, is improved. [0096] It is particularly favorable when the at least one receptacle has a cross section in the form of an elongated hole. As a result of this, a preferential orientation of the holding device relative to the storage unit can be predetermined in a simple manner. [0097] It is advantageous when the receptacle has at least one storage element projecting from the plate for connecting the storage unit to the second connecting device of a holding device. A particularly reliable connection between the holding device and the storage unit can be provided with the aid of such a storage element. [0098] It is favorable when the storage unit has at least one spacer device which spaces the plate in relation to a mounting surface for the storage unit. This makes it possible to create a distance between the plate and the mounting surface, in which at least sections of the holding devices and/or the implants can be arranged without them coming into contact with the mounting surface. [0099] It is preferred when the spacer device comprises a frame extending along the edge of the plate at least in sections. As a result of this, the storage unit can be placed on the mounting surface in a manner particularly secure against any tilting. When the frame extends along the entire edge of the plate, a space extending between the plate of the storage unit and the mounting surface, in which holding devices can be arranged at least in sections, is protected particularly well from mechanical influences. [0100] A structural module consisting of a storage unit with at least one holding device makes it possible for holding devices and/or implants required for a specific operation to be made available in an orderly manner and without additional preparation steps. This structural module can be replenished after an operation, sterilized and made available for a subsequent operation. [0101] The following description of preferred embodiments of the invention serves to explain the invention in greater detail in conjunction with the drawings. BRIEF DESCRIPTION OF THE DRAWINGS [0102] These show: [0103] FIG. 1 : a perspective view of a storage unit and a plurality of holding devices which are connected to the storage unit or released from it as well as a plurality of implants which are each connected to a holding device; [0104] FIG. 2 : a perspective view of a holding device according to a first embodiment; [0105] FIG. 3 : an exploded view of the holding device according to FIG. 2 , an implant as well as a section of the storage unit according to FIG. 1 ; [0106] FIG. 4 : a perspective view of the parts illustrated in FIG. 3 , wherein the implant is releasably connected to the holding device, wherein the holding device is releasably connected to the storage unit; [0107] FIG. 5 : a view corresponding to FIG. 4 , wherein the implant is released from the holding device with the aid of a removing tool; [0108] FIG. 6 : a perspective view of a holding device according to a second embodiment and a section of the storage unit according to FIG. 1 ; [0109] FIG. 7 : a view of the holding device according to FIG. 6 from a perspective turned through approximately 90° in relation to FIG. 6 ; [0110] FIG. 8 : a perspective view of a holding device according to a third embodiment; [0111] FIG. 9 : a view of the holding device according to FIG. 8 from a perspective turned through approximately 90° in relation to FIG. 8 ; [0112] FIG. 10 : a perspective view of a holding device according to a fourth embodiment; [0113] FIG. 11 : a view of the holding device according to FIG. 10 from a perspective turned through approximately 180° in relation to FIG. 10 ; [0114] FIG. 12 : a perspective view of a holding device according to a fifth embodiment; [0115] FIG. 13 : a view of the holding device according to FIG. 12 from a perspective turned though approximately 120° in relation to FIG. 12 ; [0116] FIG. 14 : a perspective view of a holding device according to a sixth embodiment; [0117] FIG. 15 : a view of the holding device according to FIG. 14 from a perspective turned through approximately 150° in relation to FIG. 14 ; [0118] FIG. 16 : a perspective view of a holding device according to a seventh embodiment; [0119] FIG. 17 : a view of the holding device according to FIG. 16 from a perspective turned through approximately 150° in relation to FIG. 16 ; [0120] FIG. 18 : a perspective view of a holding device according to an eighth embodiment; [0121] FIG. 19 : a view of the holding device according to FIG. 18 from a perspective turned through approximately 90° in relation to FIG. 18 ; [0122] FIG. 20 : a perspective view of a holding device according to a ninth embodiment; and [0123] FIG. 21 : a view of the holding device according to FIG. 20 from a perspective turned through approximately 150° in relation to FIG. 20 . DETAILED DESCRIPTION OF THE INVENTION [0124] The same or functionally equivalent elements are designated in all the Figures with the same reference numerals. [0125] In FIG. 1 , a storage unit which is designed for the arrangement of holding devices for implants is designated altogether with the reference numeral 2 . It has a rectangular plate 4 , the plate thickness of which is a few millimeters. A spacer device designated altogether with the reference numeral 8 extends along the edge 6 of the plate 4 . The spacer device is designed in the form of a frame 10 which comprises four walls 12 arranged in respective pairs at right angles to one another and connected to one another. The walls 12 extend at right angles to the plate 4 and space this from a mounting surface 14 , on which the storage unit 2 is placed. [0126] The plate 4 has a plurality of receptacles 16 which are each formed by openings provided in the plate 4 . The receptacles 16 are distributed over the plate 4 in a regular manner and arranged in rows 18 which are parallel to one another and columns 20 at right angles thereto. The receptacles 16 are each designed in the form of an elongated hole, wherein the longer cross-sectional axis (without any reference numeral) extends in the direction of the rows 18 and the shorter cross-sectional axis (without any reference numeral) in the direction of the columns 20 . [0127] The plate 4 has altogether 56 receptacles 16 arranged in seven rows 18 and eight columns 20 . The cross sections 22 of the receptacles 16 are of the same size and oriented identically to one another. Each receptacle 16 is limited by sections 24 of the plate 4 . More details concerning the function of the sections 24 will be explained further on. [0128] One of the receptacles 16 illustrated in FIG. 1 comprises two elongated storage elements 26 . They project from an upper side 28 of the plate 4 and extend in the direction of the rows 18 . The storage elements 26 comprise two storage sections 30 which are spaced from the upper side 28 , extend parallel to the plate 4 and limit storage areas 32 extending in the direction of the rows 18 together with the upper side 28 of the plate 4 . The function of the storage areas 32 will also be explained in detail further on. [0129] The storage unit 2 serves to accommodate and/or secure in place a plurality of holding devices which can be releasably connected to the receptacles 16 of the plate 4 . In FIG. 1 , various holding devices are illustrated which are releasably connected to the storage unit 2 , namely holding devices 34 (cf. FIGS. 4 and 5 ), holding devices 36 (cf. FIGS. 6 and 7 ), holding devices 38 (cf. FIGS. 8 and 9 ) and holding devices 40 (cf. FIGS. 10 and 11 ). In FIG. 1 , one of the holding devices 38 is illustrated in its state detached from the storage unit 2 . [0130] Each of the holding devices 34 , 36 , 38 , 40 serves for the arrangement of an implant 42 designed in the form of a screw. Each implant 42 can, as illustrated in FIG. 1 , be releasably connected to one of the holding devices 34 , 36 , 38 , 40 . [0131] The holding device 34 comprises a first connecting device 44 for releasably connecting the holding device 34 and an implant 42 as well as a second connecting device 46 for releasably connecting the holding device 34 and the storage unit 2 . [0132] The holding device 34 defines a holding axis 48 , along which an implant 42 can be arranged when the implant 42 is connected to the holding device 34 and takes up a holding position (cf. FIG. 4 ). This position of the implant 42 will be designated in the following as first holding position. [0133] A holding plane 50 , in which an approximately square, plate-like basic member 52 extends, runs at right angles to the holding axis 48 . This basic member has a visible surface 54 on the side located opposite the second connecting device 46 . The basic member 52 has a contact surface 56 on its side located opposite the visible surface 54 . [0134] The first connecting device 44 comprises an implant receptacle 58 which extends in the area of the holding axis 48 at the height of the holding plane 50 . The implant receptacle 58 is limited by a contact section 60 which is approximately semi-cylindrical and is formed by the basic member 52 . The contact section 60 is adjoined by two holding elements 62 which are tongue-shaped and arranged so as to be located opposite one another. They have at their free ends snap-in projections 64 which face one another. The snap-in projections 64 limit the implant receptacle 58 in such a manner that an undercut results. [0135] The basic member 52 has elongated spaces 66 and 68 , respectively, on the sides of the respective holding elements 62 facing away from the implant receptacle 58 . The spaces 66 and 68 have the effect that the holding elements 62 may be moved elastically in the holding plane 50 . The holding elements 62 can be moved in an opening direction 70 into the respective spaces 66 and 68 . The holding elements 62 can also each be moved in the direction towards the implant receptacle 58 in closing directions 72 which point towards one another. [0136] The holding elements 72 are illustrated in FIG. 2 in a first connecting position of the first connecting device 44 . When the holding elements 72 are deflected out of this first connecting position into the spaces 66 and 68 as a result of a first releasing force being applied, the first connecting device 44 can be transferred into a first release position. During such a transfer of the first connecting device 44 from the first connecting position into the first release position, the holding elements 72 are elastically deformed and deflected into the spaces 66 and 68 . As a result of this, the holding elements 72 each build up a first restoring force which is directed towards the implant receptacle 58 . The first restoring forces have the effect that the holding elements return to the position illustrated in FIG. 2 of their own accord following deflection into the spaces 66 and 68 . In this way, the holding elements 72 form a first restoring device 73 . [0137] The basic member 52 comprises a data storage device designated altogether with the reference numeral 74 . In the case of the holding device 34 , the data storage device 74 comprises the visible surface 54 of the basic member 52 . On the visible surface 52 , implant data 76 are arranged which are raised above the visible surface 52 and serve to identify an implant 42 which can be connected to the holding device 34 via the first connecting device 44 . The implant data 76 are alphanumeric. [0138] The second connecting device 46 , with which the holding device 34 can be connected to the storage unit 2 , comprises a connecting element 78 in the form of a curved snap-in element 80 . Together with the contact surface 56 of the basic member 52 , the snap-in element 80 limits an undercut area 82 , in which a section 24 of the plate 4 of the storage unit 2 , which is also illustrated in FIGS. 1 , 3 and 4 , can be arranged. [0139] The connecting element 78 is illustrated in FIG. 2 in a second connecting position of the second connecting device 46 . When the connecting element 78 is deformed out of this second connecting position in the direction towards the holding axis 48 as a result of a second releasing force being applied, the first connecting device 44 can be transferred into a second release position. During such a transfer of the second connecting device 46 from the second connecting position into the second release position, the connecting element 78 is elastically deformed. As a result of this, the connecting element 78 builds up a second restoring force which is directed away from the holding axis 48 . This second restoring force has the effect that the connecting element 78 returns back to the position illustrated in FIG. 2 of its own accord following its deformation in the direction towards the holding axis 78 . In this way, the connecting element 78 forms a second restoring device 81 . [0140] The holding device 34 comprises a guiding device 84 which has two flat guiding sections 86 which extend parallel to the holding axis 48 . The guiding sections 86 serve to position the holding device 34 relative to a receptacle 16 of the storage unit 2 . [0141] The holding device 34 comprises, in addition, a securing device 88 which comprises a securing section 90 which is C-shaped in cross sections at right angles to the holding axis 48 . The securing section 90 has two slits 92 which extend parallel to the holding axis 48 and are approximately rectangular. The securing section 90 has, in addition, a free end 94 on its side facing away from the basic member 52 . The cross sections of the securing section 90 at right angles to the holding axis increase in size from this free end, when seen in the direction of the holding axis 48 , as far as the level of two steps 96 . As a result of this, the cross section of the securing device 88 is greater in an area adjacent to the basic member 52 than in an area at a distance from the basic member 52 . [0142] In FIG. 3 , the holding device 34 is illustrated with an implant 42 . The implant 42 is in a position released from the holding device 34 . The implant 42 extends along an implant axis 98 . It has a first implant section 100 in the form of a screw head. This is adjoined by a short cylindrical implant section 102 . Finally, the implant 42 has an implant section 104 which is provided with an external thread 106 . The implant 42 can be secured to a body part to be operated with the aid of the external thread 106 . [0143] In order to connect the implant 42 to the holding device 34 , the implant section 102 of the implant 42 can be positioned at the level of the holding plane 50 to the side in relation to the holding device 34 . This position of the implant 42 is designated in the following as first release position. The implant 42 can be moved from this position into the implant receptacle 58 within the holding plane 50 in a connecting direction which is designated as 108 and is at right angles to the holding axis 48 . In this respect, the holding elements 62 are moved away from one another by the implant section 102 in opening directions 70 opposite to one another until the snap-in projections 64 engage interlockingly around the implant section 102 (cf. FIG. 4 ). [0144] When the implant 42 takes up its first holding position on the holding device 34 , which is illustrated in FIG. 4 , the implant section 100 extends beyond the visible surface 54 of the basic member 52 . The implant section 102 is held in the implant receptacle 58 . The implant section 104 is surrounded by the securing section 90 C-shaped in cross section at right angles to the holding axis 48 . [0145] The holding device 34 can be brought from a second release position illustrated in FIG. 3 into a position illustrated in FIG. 4 , in which the holding device 34 is connected to the storage unit 2 . This position of the holding device 34 is designated in the following as second holding position. [0146] In order to bring the holding device 34 into the second holding position proceeding from the second release position, the free end 94 of the securing section 90 of the holding device 34 can be introduced into one of the receptacles 16 of the plate 4 of the storage unit 2 . In this respect, the holding device 34 is moved in a connecting direction designated in FIG. 3 with the reference numeral 110 until the snap-in element 80 engages interlockingly behind the section 24 of the plate 4 and the contact surface 56 of the basic member 52 abuts on the upper side 28 of the plate 4 (cf. FIG. 4 ). [0147] In FIG. 4 , the first connecting device 44 is in the first connecting position. The implant 42 is connected to the holding device 34 and is in the first holding position. [0148] In FIG. 4 , the second connecting device 46 is in the second connecting position. The holding device 34 is connected to the storage unit 2 and is in the second holding position. [0149] The arrangement illustrated in FIG. 4 makes it easy for a surgeon to handle the implant 42 since it is connected to the holding device 34 and this is, on the other hand, connected to the storage unit 2 . In this respect, the implant 42 can be identified clearly with the aid of the data storage device 74 . [0150] In order to bring the implant 42 from its first holding position illustrated in FIG. 4 into the first release position illustrated in FIG. 5 , a removing tool 112 can be used. The removing tool 112 has a tool head 114 which is designed to engage around the implant section 104 . The removing tool 112 can be formed by a screwdriver which can also be used for screwing the external thread 106 of the implant 42 into a body part to be treated. [0151] In order to bring the first connecting device 44 from its first connecting position illustrated in FIG. 4 into the first release position, the removing tool 112 can be moved such that the implant 42 is handled in a first handling direction, which is designated in FIG. 5 as 116 , in a direction at right angles to the holding axis 48 so that the implant section 102 is moved out of the implant receptacle 58 within the holding plane 50 . In this respect, a first releasing force must be applied and this is determined by the resistance of the holding elements 62 which move within the holding plane 50 in opening directions 70 (cf. FIG. 3 ) into the adjoining spaces 66 and 68 for the release of the implant section 102 . [0152] As soon as the implant 42 has been moved out of the implant receptacle 58 to such an extent that it takes up the first release position, the implant 42 can be removed from the holding device 34 in a direction parallel to the holding axis 48 . In this respect, the holding device 34 remains on the plate 4 of the storage unit 2 . This is due to the fact that the second connecting device 46 can be actuated independently of the first connecting device 44 . The first connecting device 44 is transferred from the first connecting position into the first release position by the first releasing force being applied. In this respect, the second connecting device 46 remains in the second connecting position illustrated in FIGS. 4 and 5 and so the holding device 34 remains connected to the storage unit 2 . [0153] In order to transfer the second connecting device 46 into the second release position so that the holding device 34 can be released from the storage unit 2 , the holding device 34 can be handled in a handling direction 118 in a direction parallel to the holding axis 48 and moved out of the receptacle 16 of the plate 4 . For this purpose, a pressure force can be applied, for example, from the free end 94 of the securing section 90 in the direction of the second handling direction 118 . As a result of this, a second releasing force can be applied which deforms the connecting element 78 in the direction of the holding axis 48 whilst abutting on the section 24 of the plate 4 so that the second connecting device 46 is transferred from the second connecting position into the second release position. As a result of this, the holding device 34 can be released from the plate 4 . [0154] The first handling direction 116 and the second handling direction 118 extend at right angles to one another. It is understood that the transfer of the first connecting device 44 from the first connecting position into the first release position can be aided by tilting of the implant 42 through an angle of tilt 120 relative to the holding axis 48 . In this case, the first handling direction 116 and the second handling direction 118 can be oriented at an angle to one another which corresponds to a right angle plus the angle of tilt 120 . [0155] The holding device 36 illustrated in FIGS. 6 and 7 has a construction similar to that of the holding device 34 . In the following, only the differences between the holding devices 34 and 36 will be explained in detail. In contrast to the holding device 34 , the holding device 36 has not only a connecting element 78 in the form of a curved snap-in element 80 but also two connecting elements 122 and 124 which are arranged opposite one another. They extend parallel to the holding axis 48 and are connected to the securing section 90 at the free end 94 of the holding device 36 . [0156] The connecting elements 122 and 124 each have a snap-in element 126 and 128 , respectively, at their ends facing the basic member 52 of the holding device 36 . These snap-in elements are arranged at the same level as the snap-in element 80 when seen along the holding axis 48 . The connecting elements 122 and 124 are movable and deformable on their own and also relative to one another within a connecting plane 130 such that the snap-in elements 126 and 128 can be moved towards one another within the connecting plane 130 in opening directions 132 opposite to one another. As a result of this, the second connecting device 46 of the holding device 36 can be transferred from its second connecting position illustrated in FIG. 6 into the second release position. When the connecting elements 122 and 124 are spaced so near to one another in the area of the snap-in elements 126 and 128 that the snap-in elements 126 and 128 can be disengaged from the section 24 of the plate 4 , the holding device 36 can be brought from the second holding position into the second release position (cf. FIG. 7 ) in a second handling direction 118 parallel to the holding axis 48 . [0157] Once the connecting elements 122 and 124 and the snap-in elements 126 and 128 have been disengaged from the receptacle 16 of the plate 4 , the connecting elements 122 and 124 move back again in closing directions 134 opposite to one another of their own accord within the connecting plane 130 such that in the second release position of the holding device 36 the second connecting device 46 is again transferred into the second connecting position. In order to be able to connect the holding device 36 to the storage unit 2 again, the free end 94 of the securing section 90 can be introduced into the receptacle 16 until beveled run-on surfaces 136 and 138 formed by the snap-in elements 126 and 128 engage with the sections 24 of the plate 4 . As a result of this, the connecting elements 122 and 124 are moved towards one another in opening directions 132 so that the second connecting device 46 is transferred into the second release position. The beveled run-on surfaces 136 and 138 are introduced into the receptacle 16 to such an extent that the snap-in elements 126 and 128 engage interlockingly behind the section 24 of the plate 4 and, therefore, the second connecting device 46 again takes up the second connecting position. [0158] The holding device 38 illustrated in FIGS. 8 and 9 has a construction similar to that of the holding device 36 . In the following, only the differences between the holding devices 36 and 38 will, therefore, be explained in detail. The connecting elements 122 and 124 of the holding device 38 which extend parallel to the holding axis 48 are not connected to the securing section 90 at the free end 94 thereof but rather via attachments 140 and 142 which are provided adjacent to the connecting element 78 . The snap-in elements 126 and 128 are not designed in the form of projections, as in the holding device 36 according to FIGS. 6 and 7 , but are formed by edge surfaces of the connecting elements 122 and 124 pointing in the direction towards the contact surface 56 of the basic member 52 . The connecting elements 122 and 124 have, in addition, two edge sections 144 and 146 which are slightly inclined in their course relative to the holding axis 48 and make the introduction of the free end 94 into a receptacle 16 of the plate 4 easier. [0159] In order to be able to position the holding device 38 exactly relative to a receptacle 16 of the plate 4 of the storage unit 2 , the holding device 38 has guiding sections 148 and 150 which extend parallel to the holding axis 48 proceeding from the contact surface 56 and each abut on a section 24 of the plate 4 in the second holding position of the holding device 38 . The holding device 40 illustrated in FIGS. 10 and 11 differs, inter alia, from the holding devices 34 , 36 and 38 described thus far in that it defines a holding axis 48 which does not essentially extend centrally through the basic member 52 but is offset to the side in relation thereto. This has the advantage that a particularly large visible surface 54 results, on which a relatively large number of implant data 76 can be displayed closely adjacent to one another but easy to read. [0160] The implant receptacle 58 of the holding device 40 , which is limited by two holding elements 62 located opposite one another as well as the contact section 60 of the basic member 52 , is offset to such an extent out of the center of the basic member 52 that the space 68 present in the case of the holding devices 34 , 36 and 38 is no longer applicable or is formed by the surroundings of the holding device 40 . [0161] The second connecting device 46 of the holding device 40 comprises, in a similar way to the holding devices 36 and 38 , two connecting elements 122 and 124 extending essentially parallel to the holding axis 48 . In contrast to the holding devices 36 and 38 , the connecting elements 122 and 124 of the holding device 40 are provided separate from the securing section 90 of the securing device. A first connecting element 122 is designed, for example, as a leg 152 of a U which extends parallel to the holding axis 48 proceeding from the contact surface 56 of the basic member 52 as far as the free end 94 of the securing section 90 . Here, the leg 152 of the U merges into a base 154 of the U which extends parallel to the basic member 52 and, therefore, to the holding plane 50 . At its end located opposite the leg 152 of the U the base 154 of the U ends at a leg 156 of the U which forms the connecting element 124 . The legs 152 and 156 of the U and the base of the U together form a U-shaped material section 158 . The leg 156 of the U extends from the base 154 of the U approximately parallel to the holding axis 48 in the direction towards the basic member 52 and—in the area of a free end 160 which is not connected to the basic member 52 —as far as an actuating element 162 . The actuating element 162 is designed in the form of a gripping section. This gripping section and the connecting elements 122 and 124 are arranged on oppositely located sides of the basic member 52 when seen along the holding axis 48 . [0162] In order to connect the holding device 40 illustrated in FIGS. 10 and 11 to the storage unit 2 illustrated in FIG. 1 , the free end 94 of the holding device 40 can be inserted into one of the receptacles 16 of the plate 4 . The second connecting device 46 of the holding device 40 is hereby transferred from the second connecting position into the second release position with deformation of the connecting element 124 in the direction towards the holding axis 48 which corresponds to an opening direction 132 . When the holding device 40 is inserted into one of the receptacles 16 to such an extent that the snap-in elements 126 and 128 can engage interlockingly behind associated sections 24 of the receptacle 16 , the connecting element 124 springs back into the position illustrated in FIG. 10 in accordance with a closing direction 134 so that the second connecting device 46 is transferred into the second connecting position. [0163] In order to transfer the second connecting device 46 from the second connecting position into the second release position, the actuating element 162 can be actuated in accordance with the opening direction 132 which extends at right angles to the holding axis 48 . In this respect, the connecting element 124 or rather the leg 156 of the U is deformed within a connecting plane 130 so that the snap-in element 128 can disengage from the associated section 24 of the plate 4 , whereby the second connecting device 46 is transferred into the second release position. In this way, the holding device 40 can be released from the storage unit 2 during its movement in accordance with a second handling direction 118 which extends parallel to the holding axis 48 . [0164] The legs 152 and 156 of the U of the holding device 40 are arranged on oppositely located sides relative to the holding axis 48 . This has the advantage that an implant 42 connected to the holding device 40 via the first connecting device 44 is protected from mechanical influences not only by the securing section 90 but also with the aid of the U-shaped material section 158 . In this respect, the base 154 of the U shields the implant 42 in relation to the mounting surface 14 illustrated in FIG. 1 when the holding device 40 is connected to the storage unit 2 . [0165] FIGS. 12 and 13 illustrate an additional holding device 164 . This likewise comprises a U-shaped material section 158 . In contrast to the holding device 40 according to FIGS. 10 and 11 , the holding axis 48 of the holding device 164 extends approximately centrally through the basic member 52 . In addition, the holding elements 62 of the first connecting device 44 are oriented in such a manner that their opening and closing directions 70 and 72 do not extend parallel to the opening directions 132 and closing directions 134 of the connecting elements 122 and 124 , as in the case of the holding device 40 , but rather at right angles to one another. [0166] The holding device 164 has, in addition, an actuating element 166 which is rigidly connected to the basic member 52 , projects beyond the visible surface 54 and extends approximately parallel to the holding axis 48 . The actuating elements 162 and 166 are arranged on oppositely located sides of the holding axis 48 and can be moved relative to one another in the specified opening directions 132 and closing directions 134 , respectively, in order to transfer the second connecting device 46 from the second connecting position into the second release position. [0167] The basic member 52 has a reduced material thickness in a central section 168 . The central section 168 has a surface 170 which extends parallel to the visible surface 54 of the basic member 52 and is spaced at a smaller distance from the contact surface 56 of the basic member 52 than the visible surface 54 . As a result of this, the surface 170 is set back in comparison with the visible surface 54 . When the holding device 164 is connected to an implant 42 with the aid of its first connecting device 44 , an implant section 100 (cf. FIG. 3 ) does not extend beyond the visible surface 54 or only slightly. As a result of this, the holding device 164 and an implant 42 can be supplied together to an inscription device, with which implant data 76 can be applied to the visible surface 54 of the holding device 164 , for example, by way of overprinting. [0168] The holding device 164 illustrated in FIGS. 12 and 13 differs, in addition, from the holding device 40 illustrated in FIGS. 10 and 11 in that its U-shaped material section 158 has insertion aids 172 and 174 . The insertion aid 172 comprises an insertion surface 176 extending at a slight angle to the holding axis 48 . The insertion aid 174 is formed by a partially cylindrical transition section between the base 154 of the U and the leg 156 of the U. The insertion aids 172 and 174 make the insertion of the holding device 164 into a receptacle 16 of the storage unit 2 easier. [0169] FIGS. 14 and 15 illustrate a further holding device 180 . This differs from the holding devices 40 and 164 due to the fact that its U-shaped material section 158 is designed in such a manner that the legs 152 and 156 of the U are immediately adjacent to one another. The holding axis 48 of the holding device 180 extends outside a space 181 formed between the legs 152 and 156 of the U. [0170] The basic member 52 of the holding device 180 has a recess 182 extending within the holding plane 50 . This creates a space for movement of the leg 156 of the U which can be moved in opening direction 132 or in closing direction 134 with the aid of the actuating element 162 . [0171] The implant receptacle 58 of the first connecting device 44 of the holding device 180 differs from the implant receptacles of the holding devices 34 , 36 , 38 , 40 , 164 described thus far in that the holding elements 62 which are located opposite one another are comparatively short. Instead of a rigid contact section 60 (cf. FIG. 2 ), the implant receptacle 58 of the holding device 180 has contact elements 184 in the shape of circular segments. They are of a lug-shaped design and connected to the basic member 52 at the level of the visible surface 54 thereof. The contact elements 184 extend at an angle in the direction towards the holding axis 48 proceeding from the visible surface 54 . [0172] When an implant 42 is connected to the holding device 180 with the aid of the first connecting device 44 , the contact elements 184 abut on the implant section 102 (cf. FIG. 3 ) under tension. As a result of this, the implant 42 is connected to the holding device 180 without any clearance. [0173] The holding device 180 comprises an indicating device 186 , with which it can be shown whether the first connecting device 44 of the holding device 180 has been transferred from the first connecting position into the first release position at least once. The indicating device 186 comprises two tape-like indicating elements 188 which extend adjacent to the implant receptacle 58 within the holding plane 50 . The indicating elements 188 are connected to one another via a connecting section 190 which forms a predetermined breaking point. [0174] When an implant 42 connected to the holding device 180 is transferred from a first holding position into a first release position in a direction at right angles to the holding axis 48 in accordance with a first handling direction 116 , this causes destruction of the connection between the indicating elements 188 . As a result of this, it can be clearly ascertained that an implant 42 has already been removed from the holding device 180 . As a result of this, any unintentional re-use of the holding device 180 can also be ruled out. [0175] FIGS. 16 and 17 illustrate an additional holding device 192 which differs from the holding device 180 according to FIGS. 14 and 15 only in its configuration of the indicating device 186 . The indicating device 186 of the holding device 192 comprises two element sections 194 and 196 which are arranged at an oblique angle to one another. The element section 194 is articulated to a closed edge 198 of the basic member 52 and extends at an acute angle relative to the visible surface 54 of the basic member 52 in the direction towards the holding axis 48 . The element section 196 extends in the direction towards the holding axis 48 as far as adjacent to the implant receptacle 58 proceeding from the end of the element section 194 facing the holding axis 48 . [0176] When an implant 42 held on the holding device 192 is transferred from a first holding position into a first release position in a first handling direction 116 , the element sections 194 and 196 are deformed permanently and so it can be shown that the first connecting device 44 of the holding device 192 has been transferred from the first connecting position into the first release position. [0177] The holding device 200 illustrated in FIGS. 18 and 19 differs from the holding devices 180 and 192 in its configuration of the first connecting device 44 . This likewise comprises contact elements 184 which are in the shape of circular segments but no essentially tongue-shaped holding elements 62 but rather holding elements 202 which are shaped like circular segments and limit an implant receptacle 58 , which is completely enclosed on its circumferential side and extends within a holding plane 50 , together with the contact elements 184 . The holding elements 202 are connected to one another via a connecting section 190 which forms a predetermined breaking point. [0178] An implant 42 can be inserted into the holding device 200 in that it is inserted into the implant receptacle 58 in the direction of the holding axis 48 with its implant section 104 (cf. FIG. 3 ) first. In this respect, the contact elements 184 and the holding elements 202 are deformed radially outwards by the external thread 106 so that the implant section 104 can be introduced into the implant receptacle completely until the implant section 102 is arranged at the level of the contact elements 184 and the holding elements 202 and the contact elements 184 and the holding elements 202 can be reset again radially inwards. The connecting device 44 then takes up the first connecting position. In order to release the implant 42 from the holding device 200 , the first connecting device 44 can be brought from the first connecting position into the first release position in that the implant 42 is moved out of the implant receptacle 58 in a first handling direction designated as 116 . In this respect, the connecting section 190 between the holding elements 202 is destroyed. As a result of this, it can be shown that an implant 42 was already held on the holding device 200 and so any unintentional re-use of the holding device 200 can be ruled out. The holding device 200 therefore likewise comprises an indicating device 186 . With this indicating device, the indicating elements are formed by the holding elements 202 . [0179] FIGS. 20 and 21 illustrate a further holding device 204 . Its first connecting device 44 has a construction which corresponds, for example, to the construction of the first connecting device 44 of the holding device 34 according to FIG. 2 . The holding device 204 likewise has a securing section 90 which corresponds in its construction to the securing section 90 of the holding device 40 according to FIGS. 10 and 11 . [0180] On the other hand, the second connecting device 46 of the holding device 204 differs from the second connecting devices 46 of the holding devices 34 , 36 , 38 , 40 , 164 , 180 , 192 , 200 due to the fact that the snap-in elements 126 and 128 are arranged on the side of the connecting elements 122 and 124 facing the holding axis 48 . This causes a reversal of the corresponding opening directions 132 and the closing directions 134 . In addition, an undercut area 82 formed between the snap-in elements 126 and 128 and the contact surface 56 of the basic member 52 is formed between the connecting elements 122 and 124 and not on oppositely located sides. [0181] The holding device 204 can be connected to the storage unit 2 illustrated in FIG. 1 in that the securing section 90 of the holding device 204 dips into a receptacle 16 of the plate 4 until the snap-in elements 126 and 128 engage in the storage areas 32 of the storage elements 26 . The second connecting device 46 of the holding device 204 then takes up the second connecting position. [0182] In order to transfer the second connecting device 46 of the holding device 204 into the second release position, the actuating elements 162 of the connecting elements 122 and 124 can be moved towards one another in actuating directions 206 opposite to one another so that the snap-in elements 126 and 128 are moved away from one another in opening direction 132 and disengage from the storage areas 32 of the storage elements 26 .

In order to improve a holding device for an implant, comprising a first connecting device for releasably connecting the holding device and the implant, such that very small implants, in particular, are easy to handle, it is suggested that the holding device have a second connecting device for releasably connecting the holding device and a storage unit.

This application is a continuation of application Ser. No. 10/111,361, filed Aug. 5, 2002, now abandoned. The invention relates to the field of glycoprotein processing in transgenic plants used as cost efficient and contamination safe factories for the production of useful proteinaceous substances such as recombinant biopharmaceutical proteins or (pharmaceutical) compositions comprising these. The creation of recombinant proteins as e.g. medicaments or pharmaceutical compositions by pharmaco-molecular agriculture constitutes one of the principal attractions of transgenic plants; it is also the domain where their utilization is accepted best by the public opinion. In addition to the yield and the favourable cost which may be expected from the field production of recombinant proteins, transgenic plants present certain advantages over other production systems, such as bacteria, yeasts, and animal cells. Indeed, they are devoid of virus which might be dangerous to humans, and can accumulate the proteins of interest in their “organs of storage”, such as seeds or tubers. This facilitates their handling, their transportation and their storage at ambient temperature, while affording the possibility of subsequent extraction according to needs. Moreover, the transgenic plant, or some of its parts, can be utilised as vector of medicaments or of vaccines. In 1996, the team of Charles Arntzen (Boyce Thompson Institute for Plant Research, Cornell University, New York) has demonstrated the production of a recombinant vaccine against the thermolabile enterotoxin of Escherichia coli by the potato. Its efficacy has been demonstrated in mice and through clinical trials carried out on volunteers having consumed 50 to 100 grams of raw transgenic potatoes over a period of six months. Another team, at Loma Linda, in California, has successfully tested in mice a vaccine against cholera formed in the potato. Traditional vaccination against germs responsible for enteropathies is regarded as “too costly” to be generally implemented in developing countries. However, the production of oral vaccines for example no longer in the potato but in the banana, would, at a very low cost, enable general implementation of vaccination against diarrheas of bacterial origin, which cause the death of three million children every year. In the developed countries, one can imagine that children would certainly prefer a banana or strawberry vaccine to the doctor's needle. More generally, molecular pharming could enable developing countries to produce, at low cost, substantial quantities of therapeutic proteins utilizing the capacities of their agriculture, without it being necessary to invest in pharmaceutical factories. Although the advantages of plants as factories of proteinaceous substances are explained mostly in the light of biopharmaceuticals, plants are also useful for production of other proteins, e.g. industrial enzymes and the like, because of their capability of glycosylation leading e.g. to higher stability. Today, the utilisation of plants for the production of proteins or glycoproteins for therapeutic use has gone widely beyond the domain of science fiction since soy, tobacco, the potato, rice or rapeseed is the object of investigations for the production of vaccines, proteins or peptides of mammals such as: monoclonal antibodies, vaccine antigens, enzymes such as canine gastric lipase, cytokines such as epidermal growth factor, interleukins 2 and 4, erythropoietin, encephalins, interferon and serum albumin, for the greater part of human origin. Some of these proteins have already proven their efficacy in human volunteers, however, their potential immunogenicity and their possible allergenic character still restrict their development. Several heterologous proteins have successfully been produced in plants. Among these proteins are monoclonal antibodies, hormones, vaccine antigens, enzymes and blood proteins (Dieryck et al., 1997; Florack et al., 1995; Ma et al., 1995) Matsumoto et al., 1163; Saito et al., 1991; Thanavala et al. 1995) A major limitation of plants, shared with other heterologous expression systems like bacteria, yeast and insect cells, is their different glycosylation profile compared to mammals. In contrast to bacteria, having no N-linked glycans, and yeast, having only high mannose glycans, plants are able to produce proteins with complex N-linked glycans. Plant glycoproteins have complex N-linked glycans containing a α1,3 linked core fucose and β1,2 linked xylose residues not found in mammals (Lerouge et al., 1998) ( FIG. 1 ). The core of plant N-glycans can, as in mammals, be substituted by 2 GlcNAc 1 residues, which are transferred by N-acetylglucosaminyltransferase I and II (Schachter, 1991) although their appearance varies (Rayon et al., 1999. N-glycans of some plant glycoproteins contain in addition a LewisA (Fucα1,4(Galβ1,3)GlcNAc) epitope (Fitchette Laine et al., 1997; Melo et al., 1997). However, plant glycoproteins lack the characteristic galactose (NeuAcα2,6Galβ1,4) containing complex N-glycans found in mammals, while also α1,6 linked core fucose is never found ( FIG. 1 ; Schachter, 1991). A mouse monoclonal antibody produced in tobacco plants (Ma et al., 1995) has a typical plant N-glycosylation. 40% High-mannose glycans and 60% complex glycans containing xylose, fucose and 0, 1 or 2 terminal GlcNAc residues (Cabanes Macheteau et al., 1999). In short, analyses of glycoproteins from plants have indicated that several steps in the glycosylation pathways of plants and mammals are very similar if not identical. There are however also clear differences, particularly in the synthesis of complex glycans. The complex glycans of plants are generally much smaller and contain beta-1,2 xylose or alpha-1,3 fucose residues attached to the Man3 (GlcNAc)2 core. Such residues on glycoprotein are known to be highly immunogenic. This will cause problems for certain applications of recombinant proteins carrying these sugars. In addition, although common and often essential on mammalian glycoproteins, sialic acid has never been found in plant glycans. This is particularly relevant since experiments have shown, that the absence of terminal sialic acid on glycosidic side chains can dramatically decrease biological activity in vivo. Most likely, asialo-glycoprotein-receptors in the liver can bind to asialo-glycoprotein, and thereby cause a clearance of the glycoprotein from the circulation, which is reflected in a reduced metabolic half life and low bioactivity in vivo. The invention provides a plant comprising a functional mammalian enzyme providing N-glycan biosynthesis that is normally not present in plants. It is especially the “plant” character of the glycans that makes glycoproteins produced in plants less suited for pharmaceutical use. This “plant” character imparts undesired antigenic and immunogenic characteristics to the glycoprotein in question, which would require a strategy intended to prevent immunogenicity of glycoproteins produced by transgenic plants. The aim of the strategy is to modify the genome of vegetable cells in such a manner that they ripen their proteins like human cells would. Numerous genes of glycosyl transferases of mammals have already been cloned, which is not the case in plants. In view of the ease of transformation of vegetable systems, the temptation is strong to “complement” the Golgi apparatus of plants by glycosyl transferases from mammals in order to “humanize” or “mammalize” the glycans of the glycoproteins they produce. The success of such a strategy is nonetheless not evident. In particular, the galactosylation and subsequent sialylation of recombinant glycoproteins in a vegetable cell depends not only on the transfer and the expression of the gene of the galactosyl and the sialyl transferase: these foreign enzymes must also be active in the vegetable cell, without detrimental effects to the plant cell, and last but not least, without detrimental effects to the transgenic plant as a whole. To mammalise the glycosylation of plant for the production of tailor made glycoproteins in plants a xylosyltransferase and fucosyltransferase can be knocked out and at least one of several mammalian glycosyltransferases have to be expressed. Providing the xylosyltransferase and fucosyltransferase knock-outs and thereby reducing the unwanted glycosylation potential of plants is a feasible option because for example an Arabidopsis thaliana mutant mutated in the gene encoding N-acetylglucosaminyltransferase I was completely viable (Von Schaewen et al., 1993). As N-acetylglucosaminyltransferase I is the enzyme initiating the formation of complex glycans (Schachter, 1991), this plant completely lacks the xylose and fucose containing complex glycans. In a preferred embodiment, the invention provides a plant comprising a functional (mammalian) protein, e.g. a transporter or an enzyme providing N-glycan biosynthesis that is normally not present in plants additionally comprising at least a second mammalian protein or functional fragment thereof that is normally not present in plants. It is provided by the invention to produce in plants a desired glycoprotein having a mammalian-type of glycosylation pattern, at least in that said glycoprotein is galactosylated. Again, desired glycoproteins may be any useful glycoprotein for which mammalian-like glycosylation is relevant. In a preferred embodiment, the invention provides a plant according to the invention wherein said functional mammalian enzyme providing N-glycan biosynthesis that is normally not present in plants comprises (human) β1,4-galactosyltransferase. An important mammalian enzyme that is missing in plants is this β1,4-galactosyltransferase. cDNA's encoding this enzyme has been cloned from several mammalian species (Masri et al., 1988; Schaper et al., 1986). The enzyme transfers galactose from the activated sugar donor UDP-Gal in β1,4 linkage towards GlcNAc residues in N-linked and other glycans ( FIG. 1 ). These galactose residues have been show to play an important role in the functionality of e.g. antibodies (Boyd et al., 1995). β1,4-galactosyltransferase has recently been introduced in insect cell cultures (Hollister et al., 1998; Jarvis and Finn, 1996) to extend the N-glycosylation pathway of Sf9 insect cells in cell culture, allowing infection of these cultures with a baculovirus expression vector comprising a nucleic acid encoding a heterologous protein. It was shown that the heterologous protein N-linked glycans were to some extent more extensively processed, allowing the production of galactosylated recombinant glycoproteins in said insect cell cultures. Also the introduction of the enzyme into a tobacco cell suspension culture resulted in the production of galactosylated N-liked glycans (Palacpac et al., 1999) of endogenous proteins. However, no heterologous glycoproteins were produced in these plant cell cultures, let alone that such heterologous proteins would indeed be galactosylated in cell culture. Furthermore, up to date no transgenic plants comprising mammalian glycosylation patterns have been disclosed in the art. Many glycosylation mutants exist in mammalian cell lines Stanley and loffe, 1995; Stanley et al., 1996). However, similar mutations in complete organisms cause more or less serious malfunctioning of this organism (Asano et al., 1997; Herman and Hovitz, 1999; Loffe and Stanley, 1994). It is therefor in general even expected that β1,4-galactosyltransferase expression in a larger whole than cells alone (such as in a cohesive tissue or total organism) will also lead to such malfunctioning, for example during embryogenesis and/or organogenesis. Indeed, no reports have been made until now wherein a fully grown non-mammalian organism, such as an insect or a plant, is disclosed having the capacity to extend an N-linked glycan, at least not by the addition of a galactose. From many eukaryotic multicellular organisms, immortalized cell lines such as CHO, Sf9 and hybridoma cell lines have been generated. These cell lines have been cultured for many generations, can carry many mutations and lack or have lost many characteristics which are essential for functioning of the intact organisms from which they are derived. To illustrate the latter, the fact that these immortalized cell lines can not be regenerated into complete intact organisms shows that important signaling pathways and components involved in cell-cell communication are lacking in these immortalized cell lines. It is known from literature that the N-linked glycosylation machinery of immortalized eukaryotic cell lines, such as CHO cells (Stanley and Loffe, 1995; Stanley et al., 1996) or Sf insect cell lines (Jarvis and Finn, 1996; Hollister et al., 1998), can be modified without having obvious negative effects on the viability of these cell lines, whereas in contrast similar mutations in complete organisms cause more or less serious malfunctioning of the organism (Aseno et al., 1997; Herman and Horvitz, 1999; Loffe and Stanley, 1994). Indeed no reports have been made that N-linked glycosylation can be extended, in such a way that N-linked glycans are formed that naturally do not occur, in eukaryotic cells which do have the potency to regenerate into viable organisms. Apparently, as compared to normal cells, immortalized cell lines are flexible and tolerant to new, not normal types of N-linked glycosylation but lack the capacity to develop into intact organisms. Also modification of the N glycosylation machinery of immortalized tobacco BY2 cells has been reported. Introduction of GalT into this cell line results in the production of galactosylated N-linked glycans of endogenous proteins Palacpac et al., 1999). However, cells from this BY2 cell line can not be regenerated into viable tobacco plants. In addition and as described elsewhere in this patent application, the largest population was an abnormal hybrid type glycan (GlcNAc2Man5GlcNAcGal) suggesting premature action of the introduced galactosyltransferase and an abnormal Golgi morphology and localisation of the calactosyltransferase in the BY2 cell line. This provides further evidence that this cell lines is significantly different from normal tobacco plant cells. No reports have been made until now wherein a fully grown non-mammalian organism such as an insect or plant, is disclosed having the capacity to extend an N-linked glycan, at least not by the addition of a galactose. Surprisingly, the invention now provides such a non-mammalian organism, a plant having been provided a (functional) mammalian enzyme providing N-glycan biosynthesis that is normally not present in plants thereby for example providing the capacity to extend an N-linked glycan by the addition of a galactose. In a preferred embodiment, the invention provides such a plant wherein said enzyme shows stable expression. It is even provided that beyond said second mammalian protein a third mammalian protein is expressed by a plant as provided by the invention. The experimental part provides such a plant that comprises a nucleic acid encoding both an antibody light and heavy chain or (functional) fragment thereof. Of course, it is not necessary that a full protein is expressed, the invention also provides a plant according to the invention expression only a fragment, preferably a functional fragment of said second mammalian glycoprotein, said fragment having at least one activity of the whole protein and further being characterised by for example a truncated polypeptide chain, or a not fully extended glycan, for example only extended with galactose. In a preferred embodiment, the invention provides a plant according to the invention wherein said second mammalian protein or functional fragment thereof comprises an extended N-linked glycan that is devoid of xylose and/or of fucose. As can be seen from FIG. 3 , plant-derived galactosylated glycoproteins still may contain xylose and fucose residues. This in contrast to plant cell culture derived galactosylated glycoproteins (Palacpac et al., 1999) where these glycoproteins are essentially devoid of xylose and fucose residues. In plant cell cultures this is a result of the action of β1,4-galactosyltransferase on immature N-linked glycans, resulting in unnatural galactosylated ‘hybrid type’ N-linked glycans in which Golgi-mannosidase II and N-acetylglucosaminyltransferase II can not perform their function anymore. In a preferred embodiment, β1,4-galactosyltransferase is therefor expressed in plants in such a way that the enzyme acts in the Golgi apparatus on the natural substrates ( FIG. 5 ). This means, after the action of N-acetylglucosaminyltransferase I, Golgi-mannosidase II and N-acetylglucosaminyltransferase II (and in plants, provided that these enzymes are not inhibited in another way, after or during the action of xylosyltransferase and fucosyltransferase). The present invention provides an plant in which galactosylation is essentially natural like it occurs in mammals. The N-terminal cytoplasmic, transmembrane and stem region of glycosyltransferases determine the localisation of the enzyme in the ER or Golgy membrane. To provide natural or desirable glycosylation, glycosyltransferases can be expressed in plants as they occur in mammals, but can also be expressed as a fusion protein between two, or part of two, different glycosyltransferases. In this case the localisation is determined by one enzyme and the catalytic activity by a second enzyme. As example, a fusion between the cytoplasmic, transmembrane and stem region of plant xylosyltransferase and the catalitic domain of mammalian galactosyltransferase, providing an enzyme with galactosyltransferase activity and localisation of the xylosyltransferase. If one would desire to further separate glycoproteins comprising extended N-linked glycan that is devoid of xylose and/or of fucose, or to produce these in a more purified way, several possibilities are open. For one, several types of separation techniques exist, such as (immuno)affinity purification or size-exclusion chromatography or elecrtrophoresis, to mediate the required purification. Furthermore, another option is to use as starting material plants wherein the genes responsible for xylose and/or fucose addition are knocked-out. In another embodiment, the invention provides a plant according to the invention wherein said N-linked glycan comprising galactose is further comprising sialic acid added thereto. In particular, the transfer of genes coding for sialyl transferases, enzymes which catalyze the addition of sialic acid on the glycan, into vegetable systems leads to even more stable glycoproteins during in vivo usage and hence better adapted to a possible therapy. The invention herewith provides the transfer of a sialic acid biosynthesis pathway to plants. In this invention when referring to plants the whole spectrum of plants ranging from algae to trees is intended unless otherwise specified. Plants in general lack sialic acid, a sugar residue needed for the enhanced function of certain glycoproteins like antibodies and hormones, in their N-linked glycans and also the substrates for sialylation have never been found. The invention provides plants that have the capacity to produce NeuAc containing N-linked glycans on their proteins. To establish this, up to 5 different heterologous genes are expressed in plants (see Table 1). To provide plants with the biosynthetic capacity to produce sialic acid, genes encoding up to five enzymes acting in the sialic acid biosynthesis pathway are transformed to plants. These enzymes from bacterial and mammalian origin are known: GlcNAc-2 epimerase, NeuAc synthase, CMP-NeuAc synthetase, CMP-NeuAc transporter and NeuAc transferase. All genes encoding the enzymes are if desired supplied with a (FLAG) tag to follow expression, and are transformed to e.g. tobacco and corn. In another preferred embodiment, the invention provides a plant according to the invention wherein said N-linker glycan comprising galactose is further comprising or extended with glucoronic acid, glucoronyl, sulfate, sulfon, fucose, or other compound capable of extending galactose with linked to said galactose. This is particularly relevant since experiments have shown, that the absence of terminal sialic acid on glycosidic side chains can in general dramatically decrease biological activity in vivo. Most likely, asialo-glycoprotein-receptors in the liver can bind to asialo-glycoprotein, and thereby cause a clearance of the glycoprotein from the circulation, which is reflected in a reduced metabolic half life and low bioactivity in vivo. The presence of for example GlcA or another extending group but sialic acid has the same effect as the presence of sialic acid, it hinders the binding of a thus modified protein to the asialo-glycoprotein receptor of for example liver cells, thereby effectively increasing half-life, and thus clearance time, of such proteins, when used as therapeutic substance, i.e. as pharmaceutical composition. The invention thus provides an organism derived, herein in particular a plant-derived glycoprotein or functional fragment thereof comprising an extended N-linked glycan at least comprising galactose, said galactose further extended with a compound capable of extending galactose with, such as Glca to function in a similar way as silaic acid. For example, the invention provides plants that have the capacity to produce GlcA containing N-linked glycans on their proteins. To establish this, a gene encoding for example glucuronyltransferase (Terayama et al., PNAS 94:6093-6098, 1997) is expressed in plants according to the invention using methods known in the art or herein disclosed. In this aspect, the invention is not limited to plants but also provides other organisms like animals, fungi or yeast, or cell lines like mammalian cell lines or insect cell lines with the capacity to produce a glycoprotein (essentially non-sialiated) according to the invention wherein said N-linked glycan comprising galactose is further comprising or extended with for example glucuronic acid linked to galactose; which in essence has the same effect as the presence of sialic acid. The invention is not limited to extending the galactose by glucuronic acid which has the essentially the same effect as the presence of sialic acid in that it increase biological half-life and clearance time. Also sulfate, fucose or any other compound can be linked to galactose, thereby extending the carbohydrate group, by expressing a sulfotransferase, fucosyltransferase or other enzyme that transfers sulfate, fucose or other compound to galactose residues can be used to increase half-life. The invention thus provides a method to increase half-life or improve clearance time of a pharmaceutical composition comprising as active component a glycoprptein, comprising providing said glycoprotein with a compound, attached to galactose, that replaces or provides sialic acid function and thus provides at least reduced reactivity with a asialo-glycoprotein-receptor, preferably wherein said receptor is at least present on a liver-cell. Also more than one compound can be transferred to galactose, for example glucuronic acid that is extended by sulfate by expressing a sulfotransferase that transfers sulfate to glucuronic acid. The invention is not limited to those cases in which extension of galactose by other compounds than sialic acid has the same effect as extension with sialic acid. Extension of galactose by other compounds than sialic acid can have a function by its own for example in interaction with other compounds, cells or organisms. Furthermore, it has the advantage that components, otherwise extended by sialic acid, but now for example with glucoronic acid, or sulfate of fucose groups, for that matter, can easily be recognised and thus distinguished from like endogenous compounds extended with sialic acid. For example, a pharmaceutical composition comprising a glycosylated protein, such as a glycoprotein hormone, or erytrhopoetin (EPO), normally provided with sialic acid, but now with for example a sulfon, or with glucoronic acid, can easily be recognised, facilitating detection of the foreign compounds. As an example, FIG. 6 shows that tobacco plants that express human β1,4 galactosyltransferase and rat β1,3 glucuronyltransferase form the desired structure GlcAβ1,Gal on their glycoproteins as is clearly shown by the binding of a specific antibody (mouse monoclonal antibody 412) to GlcAβ1,Gal structure. Extending galactose with other compounds than silalic acid can also have advantages for the production of recombinant proteins in plants. It can make the glycoprotein or glycan of the glycoprotein more stable by preventing galactosydases and/or other glycosydases from degrading the N-glycan. It can, by doing that, increase the galactosylation. It can also be of use in a purification procedure, for example by facilitating affinity purification by specific antibodies, lectins or other compounds if desired, the compound by which galactose is extended or further comprised can, after purification of the recombinant glycoprotein, be removed, by for example a specific glycosydase, sulfatase, phosphatase, or other suitable enzyme. In another preferred embodiment, the invention provides a plant according to the invention wherein said N-linked glycan comprising galactose is further comprising other sugar residues not directly linked to galactose, for example core alphal,6 linked fucose or betal,4- or betal,6 linked N-acetylglucosamine (GlcNAc). To establish this, a gene or genes encoding for example core alphal,6 fucosyltransferase or/and GlcNAc-transferase III, GlcNAc-transferase IV, GlcNAc-transferase V and/or GlcNAc-transferase VI are expressed in plants according to the invention using methods known in the art or herein disclosed. In general, herein is provided a method to tailor N-linked glycosylation for the production of heterologous glycoproteins in plant species with typical plant like glycosylation patterns-similar to those as shown in FIG. 1 , i.e. which lack the typical mammalian proteins involved in N-linked glycosylation such as, but not limited to, betal-4 galactosyltransferases and glucoronyl transferases. Generating stably transformed plants which produce tailored glycoproteins with commercial interest can be established by inoculating plant cells or tissues with Agrobacterium strains containing a (binary) vector which comprises both nucleotide sequences encoding N-glycosylation modifying enzymes and genes encoding commercially interesting heterologous glycoproteins. Alternatively, stably transformed plants which produce tailored glycoproteins with commercial interest can be generated by simultaneous inoculation (co-transformation) of two or more Agrobacterium strains each carrying a vector comprising either nucleotide sequences encoding N-glycosylation modyfying enzymes or nucleotide sequences encoding glycoproteins of commercial interest. Alternatively, stably transformed plants which produce tailored glycoproteins with commercial interest can be generated by (multiple) crossing(s) of plants with modified N-glycosylation with plants which express nucleotide sequences encoding proteins of commercial interest. In all of these procedures, the vector may also comprise a nucleotide sequence which confers resistance against a selection agent. In order to obtain satisfactorily expression of the proteins involved in N-glycosylation and of the glycoproteins or polypeptides of commercial interest, the nucleotide sequences may be adapted to the specific transcription and translation machinery of the host plant as known to people skilled in the art. For example, silent mutations in the coding regions may be introduced to improve codon usage and specific promoters may be used to drive expression of the said genes in the relevant plant tissues. Promoters which are developmentally regulated or which can be induced at will, may be used to ensure expression at the appropriate time, for example, only after plant tissues have been harvested from the field and brought into controlled conditions. In all these cases, choice of expression cassettes of the glycosylation modifying proteins and of the glycoproteins of commercial interest should be such that they express in the same cells to allow desired post translational modifications to the said glycoprotein. In the detailed description the invention provides a plant as defined herein before according to the invention which comprises a tobacco plant, or at least a plant related to the genus Nicotiana , however, use for the invention of other relatively easy transformable plants, such as Arabidopsis thaliana , or Zea mays , or plants related thereto, is also particularly provided. For the production of recombinant glycoproteins, use of duckweed offers specific advantages. The plants are in general small and reproduce asexually through vegetative budding. Nevertheless, most duckweed species have all the tissues and organs of much larger plants including roots, stems, flowers, seeds and fronds. Duckweed can be grown cheaply and very fast as a free floating plant on the surface of simple liquid solutions from which they can easily be harvested. They can also be grown on nutrient-rich waste water, producing valuable products while simultaneously cleaning wastewater for reuse. Particularly relevant for pharmaceutical applications, duckweed can be grown indoors under contained and controlled conditions. Stably transformed Duckweed can for example be regenerated from tissues or cells after (co)-inoculating with Agrobacterium strains containing each a (binary) vector which comprises one or more nucleotide sequences of interest encoding N-glycosylation modifying enzymes and/or genes encoding commercially interesting heterologous glycoproteins. The duckweed plant may for example comprise the genus Spirodella , genus Wolffia , genus Wolffiella , or the genus Lemna, Lemna minor, Lemna miniscula and Lemna gibba. Expression in tomato fruits also offers specific advantages. Tomatoes can be easily grown in greenhouses under contained and controlled conditions and tomato fruit biomass can be harvested continuously throughout the year in enormous quantities. The watery fraction containing the glycoproteins of interest can be readily separated from the rest of the tomato fruit which allows easier purification of the glycoprotein. Expression in storage organs of other crops including but not limited to the kernels of corn, the tubers of potato and the seeds of rape seed or sunflower are also attractive alternatives which provide huge biomass in organs for which harvesting and processing technology is in place. Herewith, the invention provides a method for providing a transgenic plant, such as transgenic Nicotiana, Arabidopsis thaliana , or corn, potato, tomato, or duckweed, which are capable of expressing a recombinant protein; with the additional desired capacity to extend an N-linked glycan with galactose comprising crossing said transgenic plant with a plant according to the invention comprising at least one functional mammalian protein, e.g. a transporter or an enzyme providing N-glycan biosynthesis that is normally not present in plants, harvesting progeny from said crossing and selecting a desired progeny plant expressing said recombinant protein and expressing a functional (mammalian) enzyme involved in mammalian-like N-glycan biosynthesis that is normally not present in plants. In a preferred embodiment, the invention provides a method according to the invention further comprising selecting a desired progeny plant expressing said recombinant protein comprising an extended N-linked glycan et least comprising galactose. In the detailed description a further description of a method according to the invention is given using tobacco plants and crossings thereof as an example. With said method as provided by the invention, the invention also provides a plant expressing said recombinant protein and expressing a functional (mammalian) enzyme involved in mammalian-like N-glycan biosynthesis that is normally not present in plants. Now that such a plant is provided, the invention also provides use of a transgenic plant to produce a desired glycoprotein or functional fragment thereof, in particular wherein said glycoprotein or functional fragment thereof comprises an extended N-linked glycan et least comprising galactose. The invention additionally provides a method for obtaining a desired glycoprotein or functional fragment thereof comprising for example an extended N-linked glycan at least comprising galactose comprising cultivating a plant according to the invention until said plant has reached a harvestable stage, for example when sufficient biomass has grown to allow profitable harvesting, followed by harvesting said plant with established techniques known in the art and fractionating said plant with established techniques known in the art to obtain fractionated plant material and at least partly isolating said glycoprotein from said fractionated plant material. In the detailed description (see for example FIG. 4 ) is further explained that an antibody having been provided with an extended N-linked glycan at least comprising galactose is provided. The invention thus provides a plant-derived glycoprotein or functional fragment thereof comprising an extended N-linked glycan at least comprising galactose, for example obtained by a method as explained above. Such a plant-derived glycoprotein with an extended glycan at least comprising galactose essentially can be any desired glycoprotein that can be expressed in a plant. For example, antibodies, FSH, TSH and other hormone glycoproteins, other hormones like EPO, enzymes like antitrypsine or lipase, cellular adhesion molecules like NCAM or collagen can be produced in plants and be provided with essentially mammalian glycosylation patterns. Expression of such proteins can be performed by using a method known in the art. For example, by stable expression via Agrobacterium mediated transformation, electroporation or particle bombardment, but also by transient expression using a virus vector like PVX or other method, glycosyltransferases or an other protein extending glycan biosynthesis, and/or said glycoprotein could be expressed under control of a specific promoter to facilitate expression in certain tissues or organs. Herewith, the invention also provides use of such a plant-derived glycoprotein or functional fragment thereof according to the invention for the production of a pharmaceutical composition, for example for the treatment of a patient with an antibody, a hormone, a vaccine antigen, an enzyme, or the like. Such a pharmaceutical composition comprising a glycoprotein or functional fragment thereof is now also provided. The invention is further explained in the detailed description without limiting it thereto. DETAILED DESCRIPTION One important enzyme involved in mammalian N-glycan biosynthesis that is not present in plants is β1,4-galactosyltransferase. Here, for one, the stable expression of β1,4-galactosyltransferase in tobacco plants is described. The physiology of these plants is not obviously changed by introducing β1,4-galactosyltransferase and the feature is inheritable. Crossings of a tobacco plant expressing β1,4-galactosyltransferase with a plant expressing the heavy and light chain of a mouse antibody produced antibody having terminal galactose in similar amounts as hybridoma produced antibodies. Herein it is thus shown that the foreign enzyme can be successfully introduced in plants. A clear increase in galactose containing glycoproteins is observed. Moreover, this feature is inheritable and there is no visible phenotypical difference between the galactosyltransferase plants and wild type. A mouse monoclonal antibody produced in these plants has a degree of terminal galactoses comparable to hybridoma. produced antibody. This shows that not only endogenous proteins become galactosylated but also a recombinantly expressed mammalian protein. Materials and Methods Plasmids and Plant Transformation A plant transformation vector containing human β1,4-galactosyltransferase was constructed as follows: a 1.4 kb BamHI/XbaI fragment of pcDNAI-GalT (Aoki et al., 1992; Yamaguchi and Fukuda, 1995) was ligated in the corresponding sites of pUC19. Subsequently, this fragment was re-isolated using surrounding KpnI and HincII sites and cloned into the KpnI and SmaI site of pRAP33 (named pRAP33-HgalT). Using AscI and PacI sites the CaMV35S promotor-cDNA-Nos terminator cassette of pRAP33-HgalT was cloned in the binary vector pBINPLUS (van Engelen et al., 1995). Modifications to the published protocol are: After incubation with A. tum., leaf discs were incubated for three days in medium containing 1 mg/ml of NAA and 0.2 mg/ml BAP and the use of 0.25 mg/ml cefotaxime and vancomycine to inhibit bacterial growth in the callus and shoot inducing medium. 25 rooted shoots were transformed from in vitro medium to soil and, after several weeks, leaf material of these plants was analysed. Northern Blotting The β1,4-galactosyltransferase RNA level in the transgenic plants was analyzed by northern blotting (Sambrook et al., 1989) RNA was isolated from leafs of transgenic and control plants as described (Dé Vries et al., 1991). Ten μg of total RNA was used per sample. The blot was probed with a [ 32 P]dATP labeled SstI/XhoI fragment, containing the whole GalT cDNA, isolated from pBINPLUS-HgalT. Glycoprotein Analysis Total protein extracts of tobacco were prepared by grinding leafs in liquid nitrogen. Ground material was diluted 10 times in SDS page loading buffer (20 mM of This-HCl pH 6.8, 6% glycerol, 0.4% SDS, 20 mM DTT, 2.5 ig/ml Bromophenol Blue). After incubation at 100° C. for 5min insoluble material was pelleted. Supernatants (12.5 μl/sample) were run on 10% SDS-PAGE and blotted to nitrocellulose. Blots were blocked overnight in 0.5% TWEEN-20 in TBS and incubated for 2 hours with peroxidase conjugated RCA l20 (Ricinus Communis Agglutinin, Sigma) (1 μg/ml) in TBS-0.1% TWEEN-20. Blots were washed 4 times 10 minutes in TBS-0.1% TWEEN-20 and incubated with Lumi-Light western blotting substrate (Roche) and analysed in a lumianalyst (Roche). A rabbit polyclonal antibody directed against Horseradish peroxidase (HRP, Rockland Immunochemicals) was split in reactivity against the xylose and fucose of complex plant glycans by affinity chromatography with bee venom phospholipase according to (Faye et al., 1993). A rabbit anti LewisA antibody was prepared as described (Fitchette Laine et al., 1997). Blots were blocked with 2% milkpowder in TBS and incubated in the same buffer with anti-HRP, anti-xylose, anti-fucose or anti-Lewis-A. As secondary antibody alkaline HRP-conjugated sheep-anti-mouse was used and detection was as described above. Plant Crossings Mgr48 (Smant et al., 1997) is a mouse monoclonal IgG that has been expressed in Tobacco plants. The construct used for transformation was identical to monoclonal antibody 21C5 expressed in tobacco (van Engelen et al., 1994). Flowers of selected tobacco plants with high expression of β1,4-galactosyltransferase were pollinated with plants expressing Mgr48 antibody. The F1 generation was seeded and plants were screened for leaf expression of antibody by western blots probed HRP-conjugated sheep-anti-mouse and for galactosyltransferase expression by RCA as described above. Purification of IgGl from Tobacco Freshly harvested tobacco leaves were ground in liquid nitrogen. To 50 g of powdered plant material, 250 ml of PBS, containing 10 mM Na 2 S 2 O 5 , 0.5 mM EDTA, 0.5 mM PMSF and 5 g polyvinylpolypyrrolid, was added. After soaking for 1 hour (rotating at 4° C.), insoluble material was removed by centrifugation (15 min, 15,000 g, 4° C.). The supernatant was incubated overnight (rotating at 4° C.) with 1 ml of proteinG-agarose beads. The beads were collected in a column and washed with 10 volumes of PBS. Bound protein was eluted with 0.1 M glycine pH 2.7 and immediately brought to neutral pH by mixing with 1 M Tris pH 9.0 (50 μl per ml of eluate). Purified antibody was quantified by comparison of the binding of HRP-conjugated sheep-anti-mouse to the heavy chain on a western blot with Mgr48 of known concentration purified from hybridoma medium (Smant et al., 1997). Hybridoma Mgr48 and plant produced Mgr48 was run on 10% SDS-PAGE and blotted as described above. Detection with RCA was as described above. For antibody detection, blots were probed with HRP-conjugated sheep-anti-mouse and detected with Lumi-Light western blotting substrate as described above. Results Human β1,4-galactosyltransferase galactosylates endogenous proteins in Nicotiana tobacum. Human β1,4-galactosyltransferase (Masri et al., 1988) was introduced in tobacco plants by Agrobacterium mediated leaf disk transformation of plasmid pBINPLUS-HgalT containing a cDNA that includes a complete coding sequence. Twenty-five plants selected for kanamicin resistance were analysed for mRNA levels by northern hybridization ( FIG. 2 upper panel). The same plants were analyzed by the galactose binding lectin RCA 120 (Ricinus Cummunis Agglutinin). RCA binds to the reaction product of β1,4-GalT (Galβ1,4GlcNAc) but also to other terminal β linked galactose residues. RCA binds to one or more high molecular weight proteins isolated from non transgenic control tobacco plants ( FIG. 2 lower panel). Probably these are Arabinogalactan or similar proteins. RCA is known to bind to Arabinogalactan proteins (Schindler et al., 1995). In a number of the plant transformed with Human β1,4-galactosyltransferase, in addition, binding of RCA to a smear of proteins is observed. This indicates-that in these plants many proteins contain terminal β linked galactose residues. There is a good correlation between the galactosyltransferase RNA expression level and the RCA reactivity of the trangenic plants. Human β1,4-galactosyltransferase expressed in transgenic plants is therefor able to galactosylate endogenous glycoproteins in tobacco plants. As it is known that galactosylated N-glycans are poor acceptors for plant xylosyl- and fucosyltransferase (Johnson and Chrispeels, 1987), the influence of expression of β1,4-galactosyltransferase on the occurrence of the xylose and fucose epitope was investigated by specific antibodies. A polyclonal rabbit anti-HRP antibody that reacts with both the xylose and fucose epitope shows a clear difference in binding to isolated protein from both control and transgenic plants ( FIG. 3 ). Recombinantly Produced Antibody is Efficiently Galactosylated. The effect of expression of β1,4-galactosyltransferase on a recombinantly expressed protein was investigated. Three tobacco plants expressing β1,4-galactosyltransferase (no. GalT6, GalT8 and GalT15 from FIG. 2 ) were selected to cross with a tobacco plant expressing a mouse monoclonal antibody. This plant, expressing monoclonal mgr48 (Smant et al., 1997), was previously generated in our laboratory. Flowers of the three plants were pollinated with mgr48. Of the F1 generation 12 progeny plants of each crossing were analysed for the expression of both antibody and β1,4-galactosyltransferase by the method described in materials and methods. Of crossing GalT6xmgr48 and GalT15xmgr48 no plants were found with both mgr48 and GalT expression. Several were found in crossing GalT8xmgr48. Two of these plants (no.11 and 12), were selected for further analysis. Using proteinG affinity, antibody was isolated from tobacco plants expressing mgr48 and from the two selected plants expressing both mgr48 and β1,4-galactosyltransferase. Equal amounts of isolated antibody was run on a protein gel and blotted. The binding of sheep-anti-mouse-IgG and RCA to mgr48 from hybridoma cells, tobacco and crossings GalT8xmgr48-11 and 12 was compared ( FIG. 4 ). Sheep-anti-mouse-IgG bound to both heavy and light chain of all four antibodies isolated. RCA, in contrast, bound to hybridoma and GalT plant produced antibody but not to the antibody produced in plants expressing only mgr48. When the binding of sheep-anti-mouse-IgG and RCA to the heavy chain of the antibody is quantified, the relative reaction of RCA (RCA binding/sheep-anti-mouse-IgG binding) to GalT8xmgr48-11 and 12 is respectively 1.27 and 1.63 times higher than the ratio of hybridoma produced antibody. This shows that RCA binding to the glycans of antibody produced in GalT plants is even higher than to hybridoma produced antibody. Although the galactosylation mgr48 from hybridoma is not quantified, this is a strong indication that the galactosylation of antibody produced in these plants is very efficient. Construction of Plant Expression Vectors With cDNA's Encoding α2,6 Sialytransferase, β 1,3-Glucuronyltransferase and β1,4-Galactosyltransferase. The available β1,4-galactosyltransferase vector was not in a suitable format to easily combine with α2,6-sialyltransferase and β1,3-glucuronyltransferase clones. Therefore, by using PCR, the coding region of β1,4-galactosyl-transferase cDNA, α2,6-sialyltransferase cDNA and β1,3-glucuronyl-transferase cDNA have been cloned in plant expression vectors. Constructs are made in which galactosyltransferase is combined with either sialyltransferase or glucuronyltransferase in one vector, in order to enable simultaneous expression of the enzymes in transgenic plants after only one transformation. The galactosyltransferase expression is controlled by the 35S promoter, whereas expression of sialyltransferase and glucuronyltransferase is controlled by the 2′promoter. There is a need for an accessible and standardised source of FSH for therapeutic and diagnostic purposes, which is guaranteed to be free of LH activity. FSH preparations normally are derived from ovine or porcine pituitaries, which always implies the presence of (traces of) LH, and the risk of contamination with prion-like proteins. Substitution of brain derived FSH for plant produced recombinant FSH may be a good method of eliminating these problems. However, production of bioactive animal glycoproteins in plants, especially for therapeutic purposes, requires modification of plant-specific sugar sidechains into a mammalian type of glycans. The invention provides recombinant bFSH by infecting stably transformed tobaccoplants capable of forming mammalian type of glycans, with recombinant Tobacco Mosaic Virus TMV containing the genes for bFSH or bFSHR. Construction of Single Chain (sc) BFSH into pKS (+) Bluescript Vector, Construction of sc-bFSH-TMV and sc-bFSH-HIS-TMV In order to circumvent the need of simultaneous expression of the two separate genes of bFSH-alpha and bFSH-beta subunits in plants, we decided to construct a bFSH fusion gene. By overlap PCR we fused the carboxyl end of the beta subunit to the amino end of the alpha subunit (without a linker). In addition, we constructed a second sc-bFSH version carrying a 6× HIS tag at the C-terminus of the alpha subunit, which will allow us to purify the recombinant protein from the plant. Both, sc-bFSH and sc-bFSH-HIS constructs were subcloned into the cloning vector pKS(+) bluescript. The correctness of the clones was confirmed by sequence analysis. Sc-bFSH was subcloned into the TMV vector. Two positive clones were chosen to make in vitro transcripts and Inoculate N. Bentahamiana plants. After a few days, plants showed typical viral infection symptoms, which suggested the infective capacity of the recombinant TMV clones. In order to test whether the sc-bFSH RNA is stably expressed in systemically infected leaves, 8 days post inoculation RNA was isolated from infected N. benthamiana leaves and a reverse transcriptase polymerase chain reactions using bFSH specific primers was performed. In all cases we obtained a PCR fragment of the expected size, indicating the stability of our Sc-bFSH-TMV construct. Extracts of infected plants are used for Western blot analyses and ELISA to determine whether Sc-bFSH is expressed and folded properly. Abbreviations Used: GlcNAc, N-Acetylglucosamine; Fuc, fucose; Gal, galactose; GalT, â1,4-galactosyltransferase; RCA, Ricinus Cummunis Agglutinin; Tables TABLE 1 Enzymes of sialic acid biosynthesis pathway No enzyme Catalysed reaction localisation origin 1 GlcNAc-2 GlcNAc →ManNAc cytoplasm pig epimerase 2 NeuAc ManNAc + PEP → NeuAc cytoplasm Clos- synthase tridium 3 CMP-NeuAc NeuAc + CMP → CMP- nucleus mouse synthetase NeuAc 4 CMP-NeuAc Cytoplasm → Golgi lumen Golgi mouse transporter membrane 5 NeuAc CMP-NeuAc + Gal-R → Golgi human transferase NeuAc-Gal-R + CMP Gal UDP-Gal + GlcNac-R → Golgi human transferase Gal-GlcNAc-R + UDP BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 Major differences between mammalian and plant complex N-linked glycans. Drawn are typical N-linked glycans. Numerous variations, both extended or truncated, occur in mammals and plants. FIG. 2 Comparison of RNA levels and product of β1,4-galactosyltransferase. Upper panel: Northern blot of total RNA isolated from 25 transgenic plants, including a not transformed control plant (0), detected with a human β1,4-galactosyltransferase probe. Lower panel: Western blot of the same plant probed with RCA to detect terminal galactose residues on glycoproteins. M. indicates the molecular weight marker. FIG. 3 Western blot showing the binding of lectin and antibody to protein isolated from wild-type and a β1,4-galactosyltransferase plant (no.8 from FIG. 2 ). A: RCA as in FIG. 2 , B: anti HRP (detecting both xylose and fucose) antibody, C: anti xylose antibody, D: anti fucose antibody.) FIG. 4 Western blot showing RCA and sheep-anti-mouse-IgG binding to purified antibody produced in hybridoma culture (Hyb), tobacco plants (plant) and tobacco plants co-expressing β1,4-galactosyltransferase (GalTil and GalT12). H.C.: heavy chain, L.C. light cain. FIG. 5 Tobacco cell cultures expressing galactosyltransferase produce unnatural hybrid N-glycans while tobacco plants expressing galactosyltransferase have natural, mammalian like galactosylation. To get natural galactosylation, galactosyltransferase should act after mannosidase II and GlcNAcTransferase II. FIG. 6 Western blot showing the expression of GlcAβ1,3Gal structure in transgenic tobacco by binding of an antibody (412) directed against the glucuronic acid-galactose (GlcAβ1,3Gal) stucture to protein isolated from 8 plants expressing human β1,4 galactosyltransferase and rat β1,3 glucuronyltransferase and a wildtype controll plant (−). REFERENCES Aoki, D., Lee, N., Yamaguchi, N., Dubois, C., and Fukuda, M. N. (1992). Golgi retention of a trans-Golgi membrane protein, galactosyltransferase, requires cysteine and histidine residues within the membrane-anchoring domain. Proceedings Of The National Academy Of Sciences Of The United States Of America 89, 4319-4323. 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Immunogenicity of transgenetic plant-derived hepatitis B surface antigen. Proceedings of the National Academy of Sciences of the United States of America 92, 3358-3361. van Engelen, F. A., Molthoff, J. W., Conner, A. J., Nap, J. P., Pereira, A., and Stiekema, W. J. (1995). pBINPLUS: an improved plant transformation vector based on pBIN19. Transgenetic Res 4, 288-90. van Engelen, F. A., Schouten, A., Molthoff, J. W., Roosein, J. Salinas, J., Dirkse, W. G., Schots, A., Bakker, J., Gommers, F. J., Jongsma, M. A., and et al. (1994). Coordinate expression of antibody subunit genes yields high levels of functional antibodies in roots of transgenetic tobacco. Plant Mol Biol. 26, 1701-10. von Schaewen, A., Sturm, A., O'Neill, J., and Chrispeels, M. J. (1993) Isolation of a mutant Arabidopsis plant that lacks N-acetyl glucosaminyl transferase I and is unable to synthesize Golgi-modified complex N-linked glycans. Plant Physiol 102, 1109-18. Yamaguchi, N., and Fukuda, M. N. (1995). 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The invention relates to the field of glycoprotein processing in transgenic plants used as cost efficient and contamination safe factories for the production of recombinant biopharmaceutical proteins or pharmaceutical compositions comprising these. The invention provides plants and plant cells comprising of functional mammalian enzyme providing N-glycan biosynthesis that is normally not present in plants, for example mammalian β 1,4-galactosyltransferase, said plants or plant cells additionally comprising at least a second mammalian protein or functional fragment thereof, for example a mammalian antibody, that is normally not present in plants.

FIELD OF THE INVENTION [0001] The present invention is related to nanocomposite-based hydrogen storage material compositions and their uses as a fuel source that feeds hydrogen into a power-generating device such as a fuel cell or a hydrogen combustion engine. BACKGROUND OF THE INVENTION [0002] A major drawback in the utilization of hydrogen-based fuel cells for powering vehicles is the lack of an acceptable lightweight and safe hydrogen storage medium. Four conventional approaches to hydrogen storage are currently in use: (a) liquid hydrogen, (b) compressed gas, (c) cryo-adsorption, and (d) metal hydride storage systems. A brief description of these existing approaches is given below: (a) The liquid hydrogen storage approach offers good solutions in terms of technology maturity and economy, for both mobile storage and large-volume storage systems with volumes ranging from 100 liters to 5000 m 3 . However, the containers (dewar) for storing the liquefied hydrogen are made of very expensive super-insulating materials. (b) The compressed gas storage approach is usually applied in underground supply systems, similar to a network of natural gas pipelines. This is an economical and simple approach, but it is unsafe and not portable. Compressed hydrogen gas in a large steel tank could be an explosion hazard. (c) The cryo-adsorbing storage approach involves moderate weight and volume. In this approach, hydrogen molecules are bound to the sorbent only by physical adsorption forces, and remain in the gaseous state. The adsorbing temperature is in the range of 60 to 100° K. Activated carbon is commonly used as the sorbent due to its large number of small pores serving as hydrogen storage sites. The efficiency of H 2 uptake is no more than 7 wt %, which is equivalent to about 20 kg H 2 per cubic meter of activated carbon. The disadvantages of this approach are related to the low capacity and the cryogenic temperature required, which makes it necessary to use expensive super-insulated containers. The following two papers are directly related to this subject: (1) R. Chahine and T. K. Bose, “Low-pressure adsorption storage of hydrogen,” International J. of Hydrogen Energy, 19-2 (1994) 161-164; (2) H. Hynek, et al., “Hydrogen storage by carbon sorption,” International J. of Hydrogen Energy, 22-6 (1997) 601-610. (d) The metal hydrides can store large quantities of H 2 via a chemical reaction of H+M⇄M−H, wherein M is a selected metal element. Two major metal systems, i.e. Fe—Ti and Mg—Ni, have been applied as hydrogen storage media and have been put into use in automobiles driven by a H 2 /O 2 fuel cell. The operating temperature is 40-70° C. for the Ti—Fe system and 250-350° C. for the Mg—Ni system. The hydrogen storage capacity is less than 5 wt % for Ni—Mg and 2 wt % for Fe—Ti, which corresponds to less than 70 kg H 2 per m 3 of metals. Furthermore, metal hydride systems normally require 20-40 bar pressure to keep the hydrogen in equilibrium. This renders the container for the metal hydride too heavy and expensive, and limits the practical exploitation of these systems for portable electronic and mobility applications. [0007] More recently, researchers have expressed great interest in storing H 2 in nanostructured carbon materials. For instance, Dillon, et al. (“Storage of hydrogen in single-walled carbon nanotubes,” Nature, 386 (1997) 377-379) reported that about 0.01 wt % of H 2 was absorbed by raw carbon nanotube material (which was estimated to contain approximately 5 wt % of the single wall nanotube, SWNT) at 130° K. Chambers, et al. (“Hydrogen storage in graphite nanofibers,” J. Phys. Chem., 102 (22) (1998) 4253-4256; U.S. Pat. No. 5,653,951 (Aug. 5, 1997) and U.S. Pat. No. 6,159,538 (Dec. 12, 2000)) claimed that tubular, platelet, and herringbone-like carbon nano-fibers (CNF) were capable of adsorbing in excess of 11, 45, and 67 weight % of H 2 , respectively, at room temperature and at a pressure of 12 MPa. However, there has been no independent confirmation of these unusually high figures. [0008] The above review indicates that the hydrogen storage technology still has four major barriers to overcome: (1) low H 2 storage capacity, (2) difficulty in storing and releasing H 2 (normally requiring a high T and/or high P), (3) high costs, and (4) potential explosion danger. A need exists for the development of a new high-capacity medium that can safely store and release hydrogen at near ambient temperature conditions. If high pressures are involved in storing hydrogen, the conditions must still be safe. [0009] Teitel (“Hydrogen supply method,” U.S. Pat. No. 4,211,537 (Jul. 8, 1980); “Hydrogen supply system,” U.S. Pat. No. 4,302,217 (Nov. 24, 1981)) proposed an interesting system for supplying hydrogen to an apparatus (e.g., a combustion engine). This system contains a metal hydride-based hydrogen supply component and a micro cavity-based hydrogen storage-supply component which in tandem supply hydrogen for the apparatus. The metal hydride-based component includes a first storage tank filled with a metal hydride material which, when heated, decomposes to become a metal and hydrogen gas. When cooled, the metal will absorb hydrogen to refuel the component (via the re-formation of metal hydride). This first storage tank is equipped with a heat exchanger for both adding heat to and extracting heat from the material to regulate the absorption/desorption of hydrogen from the material. The micro cavity-based component includes a second tank containing individual micro cavities that contain or “encapsulate” hydrogen molecules held therein under high pressure. The hydrogen is released from the micro cavities by heating the cavities. This heating is accomplished by including a heating element within the micro cavity-containing tank. The metal hydride-based component supplies hydrogen for short term hydrogen utilization needs such as peak loading or acceleration. The micro cavity component supplies an overall constant demand for hydrogen and is also used to regenerate or refuel the metal hydride component. [0010] The micro cavity storage component consists of a large plurality of micro cavities filled with hydrogen gas at pressures up to 10,000 psi (689.5 MPa or 680.3 atm). The micro cavities generally are micro-spheres with a diameter from about 5 to about 500 microns. The walls of the micro cavities are generally from about 0.01 to about 0.1 that of the diameter of the micro cavities. The filled micro-spheres may be moved from operation to operation like a fine sand or suspended in a gas or fluid for transportation. Hollow micro-spheres can be made of plastic, carbon, metal, glasses or ceramics depending upon the performance characteristics desired. Teitel suggested the preferred micro-spheres to be made of silicate glasses. Under refueling conditions (e.g., under high hydrogen pressures and elevated temperatures) hydrogen will diffuse into the micro cavities. When stored at normal temperatures and under atmospheric pressure the hydrogen remains inside the micro cavity under high pressure. Upon reheating the micro cavity, the hydrogen is caused to diffuse outside the cavity and is available for utilization by the apparatus. [0011] Advantages of the Teitel System: The present inventor envisions that hollow micro spheres provide a much safer method for storing and transporting hydrogen. Each micro-sphere acts as its own pressure vessel. At 50 μm or smaller in diameter and with a wall of 1 μm or less in thickness, each micro-sphere contains a minute amount of hydrogen. However, a large number of micro-spheres can be bunched together in a tank which can be made out of light weight materials such as plastics due to the fact that the tank does not have to be under a high pressure. This would make for a sizeable storage system that weighs much less than a traditional heavy steel tank. In an accident, the micro-sphere system would not break to release a large quantity of hydrogen, as would the rupture of a big tank of gas. Instead, some of the micro-spheres would just spill onto the ground. A limited number of micro-spheres could possibly break, but releasing only minute amounts of hydrogen. [0012] It is further envisioned that, when fully implemented for automotive applications, the system could provide a level of convenience comparable to the situation of today's drivers filling up their cars with gasoline at a convenient gas station. The refueling of micro-spheres in a car could be accomplished in two steps. First, a vacuum would suck the used micro-spheres out and send them to a tank for refilling of hydrogen. New, hydrogen-filled micro-spheres could then pumped in from a different tank. The consumer would not see much difference from today's system. The micro-spheres are very light, inexpensive and can be repeatedly filled and refilled without degradation. [0013] Shortcomings of the Teitel System: (1) The system requires two tanks: one primary tank containing heavy metal hydride and the supplementary micro-sphere tank; the latter primarily playing a secondary role of recharging the primary tank. Such a heavy and complex system may not be very suitable for automotive and aerospace applications and is totally unfit for portable device applications (e.g., for use in fuel cells to power computers, cell phones, and other micro-electronic devices). It would be advantageous to utilize a hydrogen supply system based on micro-spheres alone. (2) In the Teitel system, heating of the micro-spheres for releasing the hydrogen requires blowing the micro-spheres with hot gases or powering an electrical heating element to heat up the micro-spheres. In either case, a significant amount of energy would be consumed to heat the glass or ceramic spheres to a temperature close to the glass transition temperature or softening point in order to achieve a reasonable hydrogen gas release rate. This is because both glass and ceramic materials have very high glass transition and softening points (hereinafter denoted as Tg) and, as such, have very low gas permeability at room temperature, which is a good feature for hydrogen storage but is bad for hydrogen release when a fuel cell needs a good hydrogen supply rate. By contrast, polymers have a relatively high permeation coefficient at room temperature and the coefficient normally becomes even greater when the temperature approaches Tg. This is an undesirable feature for hydrogen storage, but can be good for hydrogen release. (3) A maximum hydrogen storage pressure of 10,000 psi, cited by Teitel, reflects the notion that this pressure is limited by the tensile strength of the micro-sphere shell or wall material. The use of conventional plastic, carbon, glass, and ceramic micro-spheres with a diameter of 5-500 μm cannot be reliably used to contain hydrogen at any pressure near 10,000 psi or higher. [0014] Hence, an object of the present invention is to provide a material composition that has a higher hydrogen storage capacity. Such a composition can be used in a safe, reliable, and simple hydrogen storage and supply system that is capable of feeding hydrogen fuel to a power-generating device such as a hydrogen combustion engine or fuel cell. [0015] Another object of the present invention is to provide a hydrogen storage and supply material that is particularly suitable for feeding hydrogen fuel to fuel cells for use in apparatus such as portable electronic devices, automobiles and unmanned aerial vehicles (UAV) where device weight is a major concern. [0016] Still another object of the present invention is to provide a hydrogen storage and supply material composition and a related method that, in combination, are capable of feeding hydrogen fuel to fuel cells at an adequate and controlled rate. SUMMARY OF THE INVENTION [0017] In one preferred embodiment, the present invention provides a core-shell composition for gas storage and supply applications. The core comprises a hollow or porous structure and the shell comprises a nanocomposite material. This nanocomposite is primarily composed of an exfoliated layered filler, in the form of separate, thin platelets, dispersed in a matrix material (preferably a polymer). The layered filler preferably includes a platelet having a dimension smaller than 200 nanometers and an aspect ratio greater than 25. The filler comprises an exfoliated graphite (containing nano-scaled graphene plates) or an exfoliated clay (ultra-thin silicate platelets). The silicate-based filler may be selected from the group consisting of bentonite, vermiculite, montmorillonite, nontronite, beidellite, volkonskoite, hectorite, saponite, laponite, sauconite, magadiite, kenyaite, ledikite and mixtures and solutions thereof. The nanocomposite has a tensile or flexural strength typically greater than 10,000 psi or 689.5 MPa and more typically greater than 50,000 psi or 3.45 GPa when a desired platelet orientation is achieved. Preferably, the nanocomposite contains a volume fraction of nano platelet filler in the range of 0.1% to 30% to achieve the desired strength and gas permeability properties. [0018] Another preferred embodiment of the present invention is a normally closed container that contains therein a plurality of the aforementioned nanocomposite shell-core compositions to store gas molecules inside the compositions. The container is equipped with means for releasing the gas molecules. [0019] In another embodiment, a hydrogen gas storage and supply method is disclosed. The method comprises the following steps: (a) providing a plurality of nanocomposite based shell-core compositions as defined above with these compositions being pre-filled with pressurized hydrogen gas and enclosed in a container, wherein the compositions comprise a polymer having a glass transition temperature or softening temperature, Tg, no greater than 300° C.; and (b) heating the shell-core compositions to a temperature within the range of [Tg−20]<T<[Tg+20], or sufficient to cause diffusion of hydrogen outside the compositions to provide hydrogen fuel from the container to a hydrogen-consuming device such as a fuel cell or hydrogen fuel combustion engine. BRIEF DESCRIPTION OF THE DRAWINGS [0020] FIG. 1 Schematic of prior-art shell-core spheres: (a) shell-hollow core sphere and (b) shell-porous core spheres with the shell and pore wall being made of a plastic or glass material. [0021] FIG. 2 Schematic of a core-shell structure: (a) nanocomposite shell-hollow core, (b) nanocomposite shell-porous core, (c) nanocomposite shell-intermediate shell-hollow core, (d) nanocomposite shell-intermediate shell-porous core, and (e) a minute volume element of the nanocomposite shell. [0022] FIG. 3 Schematic of a nanocomposite shell-multiple-cavity core structure: (a) core containing a plurality of hollow micro-spheres and (b) core containing a plurality of porous micro-spheres. [0023] FIG. 4 Procedures that can be followed to produce nanocomposite shell-core composition; (a)-( c)-(e) for shell-hollow core micro-spheres and (b)-(d)-(f) for shell-porous core micro-spheres. [0024] FIG. 5 Hydrogen release rate of nano-scaled graphene platelet-polystyrene nanocomposite shell-porous core micro-spheres as a function of the micro-sphere temperature. [0025] FIG. 6 Schematic of a container containing a multiplicity of nanocomposite shell-core compositions capable of being heated to supply hydrogen gas to a fuel cell. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS [0000] A. Nanocomposite Shell-Core Compositions [0026] Two prior-art shell-core (or core-shell) compositions that can be used to store and supply hydrogen fuel to a fuel cell or other hydrogen-consuming apparatus, as perceived by Teitel, are schematically shown in FIG. 1 ( a ) and FIG. 1 ( b ). These compositions are also herein referred to as spheres or micro-spheres, although they are not necessarily spherical in shape. The composition shown in FIG. 1 ( a ) is composed of a glass or plastic shell 12 and a hollow core 14 . The shell 12 provides the needed mechanical integrity to contain gas molecules inside the hollow core 14 under a reasonably high gas pressure, P. The composition shown in FIG. 1 ( b ) is composed of a glass or plastic shell 12 and a micro- or nano-porous core 16 . The shell 12 provides the needed mechanical strength to contain gas molecules inside the pores 18 of the porous core 16 under a gas pressure, P. Individual pores, nanometer- or micrometer-scaled, are separated by a pore wall 19 . The maximum pressure that these shell-core compositions can withstand is dictated by the shell and pore wall strength. Gas molecules inside these small “pressure vessels” tend to gradually diffuse through the shell and escape into the open air unless the shell has a high resistance to gas permeation. [0027] The glass, ceramic, carbon or plastic spheres as conceived by Teitel suffer from the following problems: (1) Plastics and bulk carbon materials are weak and ceramic and glass materials are brittle. Although ceramic and glass materials can have a high strength under compression, they normally exhibit a very low strength under tension due to their brittleness (not resistant to crack initiation and growth). (2) The sphere size range, 5-500 μm, as suggested by Teitel, is not a most desirable range due to the fact that the defect size and number of defects in a ceramic or glass part tend to scale with the part dimension. This implies that larger parts tend to have a lower strength. It would be most desirable to keep the glass shell-core spheres under 5 sum in diameter, which was not recognized by Teitel. (3) Although polymers (including plastics and rubbers) by themselves are of low density, they tend to show high gas permeability values. Ceramic and glass materials, although showing somewhat better gas permeation resistance, are of high density and more difficult to process. Further, when demanded, hydrogen gas molecules are not able to diffuse out of rigid glass or ceramic structures at a sufficiently high rate unless the materials are heated to very close to their glass transition or softening points (Tg), which are very high for both glass and ceramic materials. [0028] A re-visit of the ideal gas law (n/V=P/RT) indicates that the number of moles (n) of hydrogen molecules that can be stored in a micro-sphere of volume (V) is proportional to the internal pressure (P), which is limited by the micro-sphere strength. For instance, by increasing the shell strength of the shell-core micro-sphere from 5,000 psi to 50,000 psi, one can increase the hydrogen storage capacity by 10 times. The gas-retaining ability of shell-core micro-spheres can be improved if the gas permeability of the shell structure is reduced. Both technical goals have been achieved by the presently invented shell-core compositions with the shell comprising a platelet-reinforced nanocomposite material, as schematically shown in FIG. 2 . [0029] As a preferred embodiment of the present invention, the shell-core structure of FIG. 2 ( a ) features a nanocomposite shell 22 and a hollow core 24 and that of FIG. 2 ( b ) a nanocomposite shell 22 and a porous core 26 . The porous core contains micro- and/or nano-porous pores or cavities separated from one another by a thin wall or membrane. This wall can be of the same material composition as the shell, but can be different, e.g., made of a polymer. The shell-core composition of FIG. 2 ( c ) contains a hollow core 28 formed by an intermediate shell 32 , which is in turn fully encapsulated by an outer shell 22 of nanocomposite. FIG. 2 ( d ) shows a similar composition, with an outer nanocomposite shell 22 , an intermediate shell 34 , and a porous core 30 . The intermediate shell in either FIG. 2 ( c ) or FIG. 2 ( d ), and the pore wall in FIG. 2 ( d ) may be composed of a polymer, glass, ceramic, or carbon. The shell thickness is preferably smaller than 50% of the radius of a shell-core sphere, preferably smaller than 20%, and most preferably smaller than 10% in order to maximize the gas storage volume. [0030] FIG. 2 ( e ) schematically shows a minute volume element of the nanocomposite shell, which is composed of expanded, exfoliated or separated graphite or clay layers (platelets) dispersed in a polymer matrix. These platelets have one dimension (thickness) smaller than 200 nanometers (nm), preferably smaller than 100 nm, and most preferably smaller than 20 nm. The other two dimensions (length and width, or diameters) preferably are 1 μm or smaller. The aspect ratio is defined to be a diameter-to-thickness ratio of a substantially circular thin platelet, or a length-to-thickness or width-to-thickness ratio in a substantially rectangular platelet. At least one aspect ratio is preferably greater than 25 and further preferably greater than 50. Further more preferably, both length-to-thickness and width-to-thickness ratios are greater than 25 and most preferably greater than 50. These features are in favor of the formation of overlapping or percolated platelets in a direction approximately perpendicular to the radial direction of a shell-core micro-sphere. [0031] The configuration of overlapping or percolated platelets forms a great barrier against permeation of gas when the hydrogen-filled micro-sphere is in a fuel storage state, typically at room temperature, i.e., no fuel is being drawn out of the micro-sphere. The platelets have an extremely high strength along essentially all directions on the thin platelet plane (normal to the thickness direction). If these platelets are oriented along the tangential direction (with respect to the micro-sphere) or perpendicular to the micro-sphere radial direction, they impart an extremely high tensile strength to the shell that helps to dramatically increase the tolerable internal gas pressure, P. This leads to a greatly enhanced hydrogen storage capacity (n/V). [0032] Nanocomposites are compositions in which at least one of its constituents has one or more dimensions, such as length, width or thickness, in the nanometer size range. The nanocomposite of the presently invented shell-core structure is further characterized as follows: The platelet fillers may be selected from two broad categories of materials that have extremely thin layers or platelets being laminated together: graphite-like and clay materials. These basically layer-like structures may be subjected to exfoliation treatment to produce individual layers or a small number of layers (e.g., 2-100 layers bonded together) each having a thickness that can be as small as 0.34 nm, but typically in the range of 1-100 nm. Once exfoliated and separated from one another, these platelet structures (typically 1-100 layers) may be uniformly dispersed throughout a matrix polymer. The relatively large surface area of the clay or graphite platelet filler, if uniformly dispersed, may provide more interfaces between the filler and the polymer, and may subsequently improve the physical properties, by reducing the mobility of the polymer chains at these interfaces and by providing exceptional stress-bearing capabilities. Most significant feature for hydrogen storage applications is the notion that these platelets are extremely compact, ordered structures that are covalent-bonded along all directions on the platelet plane and, hence, are highly effective barriers against gas diffusion. [0033] As another embodiment of the present invention, the nanocomposite shell 52 may encapsulate a multiplicity of hollow micro-spheres ( FIG. 3 ( a )) or a multiplicity of porous micro-spheres ( FIG. 3 ( b )). The hollow micro-spheres may each be comprised of a shell 54 and a hollow core 56 . The porous micro-spheres may each be comprised of a shell 54 and a micro- or nano-porous core 58 . Again, the shell and pore wall material may be a polymer, glass, ceramic, carbon, or composite material. These slightly larger multi-cavity particles have an advantage in that the amount of nanocomposite shell material needed is lower than if individual micro-spheres are each encapsulated by a nanocomposite shell. However, these particles are preferably kept to be smaller than 100 μm in size, further preferably smaller than 10 μm and most preferably smaller than 5 μm to reduce the potential defect size in the nanocomposite shell 52 . [0000] B. Preparation of Polymer-Clay Nanocomposite Shell-Core Compositions [0034] The diagrams in FIG. 4 schematically illustrate preferred ways of preparing the polymer-platelet nanocomposite shell-core compositions, including both clay- or graphite-based platelets. Shown on the left-hand side of FIG. 4 is a procedure for preparing a nanocomposite shell-hollow core structure. The procedure begins with the preparation of shell-hollow core micro-spheres ( FIG. 4 ( a )) with a non-composite shell material (e.g., a polymer), which is then coated with a thin nanocomposite coating composition to form a structure as shown in FIG. 4 ( c ), which is the desired structure indicated in FIG. 2 ( c ). If a structure like FIG. 4 ( e ) or FIG. 2 ( a ) is desired, the intermediate shell 12 in FIG. 4 ( c ) may then be removed through a solvent dissolving or leaching step. [0035] Shown on the right-hand side of FIG. 4 is a procedure for preparing a nanocomposite shell-porous core structure. The procedure begins with the preparation of shell-porous core micro-spheres ( FIG. 4 ( b )) with a non-composite shell material (e.g., a polymer), which is then coated with a thin nanocomposite coating composition to form a structure as shown in FIG. 4 ( d ), which is the desired structure indicated in FIG. 2 ( d ). If a structure like FIG. 4 ( f ) or FIG. 2 ( b ) is desired, the intermediate shell 12 in FIG. 4 ( d ) may then be removed through a solvent dissolving or leaching step. The space created can be naturally filled in by the un-cured or partially cured nanocomposite shell material that is still capable of flowing at this stage. [0036] A clay mineral is typically composed of hydrated aluminum silicates that are fine-grained and have a platelet-forming habit. The crystalline structure of a typical clay mineral is a multi-layered structure comprised of combinations of layers of SiO 4 tetrahedra that are joined to layers of AlO(OH) 2 octahedra. The term “gallery” is used herein to describe the interlayer space of the layered clay minerals. The terms “d-spacing” or “basal spacing” define the sum of the single layer thickness and the thickness of the interlayer or gallery, which is the repeat unit of the multi-layer mineral. The gallery may contain water and/or other constituents such as potassium, sodium, or calcium cations, depending on the clay type. Clay minerals may vary with respect to the combination of their constituent layers and cations. Isomorphic substitution of the cations of clay mineral, such as Al 3+ or Fe 3+ substituting for the Si 4+ ions in the tetrahedral network, or Al 3+ , Mg 3+ or Fe 3+ substituting for other cations in the octahedral network, occurs quite commonly. These substitutions may impart a net negative charge on the clay structure. Naturally occurring elements within the gallery of the clay, such as water molecules, sodium cations or potassium cations, are attracted to the surface of the clay layers due to this net negative charge. [0037] Polymer-clay nanocomposites can be characterized as being one of several general types: intercalated nanocomposite, exfoliated nanocomposite, or combinations thereof. The term “intercalated nanocomposite” describes a nanocomposite that consists of a regular insertion of the polymer in between the clay layers. The term “exfoliated nanocomposite” describes a nanocomposite wherein the 1 nm-thick layers of clay are dispersed in the matrix forming a composite structure on the micro-scale. The latter type of composite, or exfoliated nanocomposite, maximizes the polymer-clay interactions thereby making the entire surface of the clay layers available for the polymer. This modification may lead to the most dramatic changes in mechanical and physical properties of the resulting polymer. In contrast, the term “conventional composite” describes a composite where the clay acts as a conventional filler and is not dispersed on a nano-scale. These composites generally do not exhibit the improvement in mechanical and physical properties seen with exfoliated nanocomposites. In certain embodiments of the present invention, some portion of the clay in the polymer-clay nanocomposites may exist as structures larger than exfoliated or intercalated composites. [0038] The silicate-based clay filler used in the present invention may be selected from the group consisting of bentonite, vermiculite, montmorillonite, nontronite, beidellite, volkonskoite, hectorite, saponite, laponite, sauconite, magadiite, kenyaite, ledikite and mixtures and solutions thereof. Due to the nanoscale dimensions of the reinforcement phase, nanocomposites display unique and improved properties compared to that of micro- or macro-composites. A wealth of unique properties and technological opportunities are offered by these materials. [0039] The exfoliation of layered clay-like materials is well-known in the art. For instance, phyllosilicates, such as smectite clays (e.g., sodium montmorillonite and calcium montmorillonite), can be treated with organic molecules, such as organic ammonium ions, to intercalate the organic molecules between adjacent, planar silicate layers, thereby substantially increasing the interlayer (interlaminar) spacing between the adjacent silicate layers. The thus-treated, intercalated phyllosilicates, having interlayer spacing of at least about 10-20 Angstroms (1-2 nm) and up to about 100 Angstroms (10 nm), then can be exfoliated (e.g., the silicate layers are separated) mechanically (e.g., by high shear mixing) or thermally (e.g., rapid temperature rising). The individual silicate layers, when admixed with a matrix polymer, before, after or during the polymerization of the matrix polymer (e.g., a polyamide) have been found to substantially improve one or more properties of the polymer, such as mechanical strength and/or high temperature characteristics. [0040] The intercalate may be formed, with the interlayer spacing between adjacent silicate platelets being increased, by adsorption of a silane coupling agent or an onium cation, such as a quaternary ammonium compound, having a reactive group which is compatible with the matrix polymer. Such quaternary ammonium cations are well known to convert a highly hydrophilic clay, such as sodium or calcium montmorillonite, into an organophilic clay capable of sorbing organic molecules. Direct intercalation (without solvent) of several polymers such as polystyrene and poly(ethylene oxide) in organically modified silicates also have been reported. For the purpose of preparing a coating or suspension solution composition containing a polymer-clay nanocomposite for use in practicing the present invention, one may choose to prepare an exfoliated clay platelet phase dispersed in a monomer or oligomer matrix (referred to as a reactive matrix), which can be polymerized to become a thermoplastic material or cured to become a thermoset resin. The matrix may be a thermoplastic that is used to directly intercalate the layer galleries. The resulting nanocomposite may be diluted with a dilutant or solvent to control the solution or suspension viscosity. [0041] Methods for the production of polymer particles that are hollow or core-sheath polymer particles that contain voids (pores) are disclosed by Blankenship, et al. (U.S. Pat. No. 4,594,363 (Jun. 10, 1986)); Touda, et al. (U.S. Pat. No. 5,077,320, (Dec. 31, 1991)); and Walt, et al. U.S. Pat. No. 6,720,007 (Apr. 13, 2004). For instance, Blankenship, et al developed a process for making core-sheath polymer particles containing voids. The process includes (A) emulsion-polymerizing a core from a core monomer system comprised of at least one ethylenically unsaturated monomer containing acid functionality; (B) encapsulating the core with a hard sheath by emulsion polymerizing a sheath monomer system in the presence of the core with the sheath permitting penetration of fixed or permanent bases; (C) swelling at elevated temperature the resultant core-sheath polymer particles with fixed or permanent base so as to produce a dispersion of particles which, when dried, contain a microvoid. The process proposed by Touda, et al can be used to produce polymer particles containing one void or multiple voids. The process includes (a) adding a base to a latex of a carboxyl-modified copolymer containing 0.1 to 1000 parts of an organic solvent per 100 parts by weight of the carboxyl-modified copolymer to neutralize at least part of the carboxyl groups in the copolymer, and (b) adding an acid to the latex to adjust the pH of the latex to not more than 7. [0042] The polymer core-sheath particles prepared from the above-cited procedures or other prior-art processes may then be coated with a nanocomposite-containing solution or suspension. Procedures for coating of polymer particles or glass beads by a solution or suspension are also well-known in the art. We have found the following procedures suitable for producing nanocomposite shell-hollow core and nanocomposite shell-porous core micro-spheres. In a simple approach, one may disperse the hollow polymer micro-spheres or the polymer shell-porous core spheres in a diluted nanocomposite suspension or solution with the resulting liquid mixture being subjected to ultrasonic waves to avoid excessive agglomeration of coated particles. The solvent or dilutant is then removed to produce dry particles such as those shown in FIG. 4 ( c ) or FIG. 4 ( d ). In some cases, the products were found to contain particles as shown in FIG. 3 ( a ) and FIG. 3 ( b ) due to agglomeration. [0043] If so desired, the solvent may be selected in such a manner that the solvent can penetrate through the nanocomposite shell and then dissolve the intermediate polymer shell (e.g., 12 in FIG. 4 ( c ) or FIG. 4 ( d )) and eventually at least partially leach out the intermediate shell material. This material can be made to be of lower molecular weight and non-cross-linked chains to facilitate dissolution and leaching to produce the structures of FIG. 4 ( e ) or FIG. 4 ( f ). [0044] Alternatively, the dried hollow polymer micro-spheres or polymer shell-porous core micro-spheres may be forced to flow around inside a fluidized bed while a stream of nanocomposite suspension or solution is sprayed over these micro-spheres. This process tends to produce individual nanocomposite shell-core particles with significantly reduced level of agglomeration. The particles are mostly those depicted in FIG. 2 ( c ) and FIG. 2 ( d ), with a minimal amount of particles such as those in FIG. 3 ( a ) or FIG. 3 ( b ). [0045] Direct production of nanocomposite shell-core compositions without going through the intermediate step of forming polymer or glass micro-spheres is described as follows: Lorah, et al. (U.S. Pat. No. 6,759,463, Jul. 6, 2004) proposed a method for preparing hollow polymer-clay nanocomposite particles from ethylenically unsaturated monomers. The method includes providing an aqueous emulsion of a multi-stage emulsion polymer. The multi-stage emulsion polymer comprises: (a) a core stage polymer including an aqueous polymer-clay nanocomposite composition comprised of polymerized units of at least one ethylenically unsaturated monomer, at least one unmodified clay, and at least one modifying agent wherein the clay is lightly modified prior to the formation of the shell stage polymer and (b) a shell stage polymer comprising polymerized units of at least one ethylenically unsaturated monomer and at least one lightly modified clay. The core stage polymer is swollen with at least one swelling agent and optionally one ethylenically unsaturated monomer such that at least a portion of the core stage polymer contacts at least a portion of the shell stage polymer. The monomer is then polymerized to form the polymer-clay nanocomposite particles which become hollow upon drying. [0046] This method was an extension of the method cited earlier (e.g., by Blankenship, et al., U.S. Pat. No. 4,595,363) for producing hollow polymer sheath-core particles. However, we have found that this method, as proposed by Lorah, et al. tends to produce a particle with a very thick wall and very small hollow core; typically with the wall thickness greater than 50%-70% of the particle radius. This certainly would have resulted in having only a small space for gas storage. Apparently, Loral, et al. have not recognized that these particles can be used for hydrogen storage and have not fairly suggested how one could obtain properly sized hollow structures. We have found that, with the polymer compositions as suggested by Lorah, et al, one must swell the core stage polymer by a linear factor of approximately 2.5 (radius enlarged by a factor of 2.5) in order to achieve a hollow particle with a wall thickness smaller than 50% of the total particle radius when the particle is dried after polymerization of the shell. [0000] C. Preparation of Polymer-Graphite Platelet Nanocomposite Shell-Core Compositions [0047] The applicant and his colleagues have recently developed a process for producing individual nano-scaled graphite planes (individual graphene sheets) and stacks of multiple nano-scaled graphene sheets, which are collectively called “nano-sized graphene platelets (NGPs).” The structures of these materials may be best visualized by making a longitudinal scission on the single-wall or multi-wall of a carbon nano-tube along its tube axis direction and then flattening up the resulting sheet or plate. These nano materials could potentially become cost-effective substitutes for carbon nano-tubes or other types of nano-rods for various scientific and engineering applications. [0048] NGPs can be readily produced by the following procedures: (1) providing a graphite powder containing fine graphite particles (particulates, short fiber segments, carbon whisker, graphitic nano-fibers, or combinations thereof) preferably with at least one dimension smaller than 200 μm (most preferably smaller than 1 μm); (2) exfoliating the graphite crystallites in these particles in such a manner that at least two graphene planes are either partially or fully separated from each other, and (3) mechanical attrition (e.g., ball milling) of the exfoliated particles to become nano-scaled to obtain the resulting NGPs. The starting powder type and size, exfoliation conditions (e.g., intercalation chemical type and concentration, and temperature cycles), and the mechanical attrition conditions (e.g., ball milling time and intensity) can be varied to generate, by design, various NGP materials with a wide range of graphene plate thickness, width and length values. This implies that the aspect ratios such as length-to-thickness ratio and width-to-thickness ratio (for an approximately rectangular platelet) or diameter-to-thickness ratio (for an approximately cylindrical platelet or “disk”) can be custom-made. We have found that these ultra-high strength NGPs impart extremely high strength and stiffness to a polymer when NGPs are properly dispersed in the matrix polymer to form a nanocomposite. [0049] Once a nanocomposite suspension or solution is prepared, similar procedures as described earlier for polymer-clay nanocomposite may be followed to prepare the desired NGP-based nanocomposite shell-core compositions for hydrogen storage. These NGP nanocomposite micro-spheres exhibit much high strength than their clay-based counterparts. EXAMPLE 1 Preparation of Nano-Scaled Graphene Plate (NGPs) Based Nanocomposites [0050] Natural flake graphite with an average size of 500 μm was subjected to an acid treatment by preparing a mixture of concentrated sulfuric acid and nitric acid at a 4:1 ratio, mixing a desired amount of graphite flakes in this acid mixture, and stirring the resulting “slurry” continuously for 16 hours. The acid-treated graphite sample was washed with water and then dried at 90° C. to remove water. The dried particles were then placed in a furnace preset at 650° C. for 2 minutes to obtain exfoliated graphite, which was then subjected to a mechanical attrition using a high-intensity planetary ball mill for 24 hours to produce NGPs. Portions of this NGP sample were then mixed with a matrix polymer or monomer to prepare several master batches of NGP-based nanocomposite coating compositions: Master batch (A): Suspensions comprising NGPs+Polystyrene+toluene Master batch (B): Mixtures of NGPs+epoxy resin+curing agent Master batch (C): Latex emulsions of NGPs EXAMPLE 1 -A From Expandable Polystyrene Beads [0051] The production procedures for foamed plastics are adapted herein for the preparation of porous plastic beads. Micrometer-sized polystyrene (PS) beads were subjected to a helium gas pressure of approximately 7 atm and a temperature near 90° C. (inside a pressure chamber) for two hours, allowing helium gas molecules to diffuse into PS beads. The chamber was then cooled down to room temperature under a high helium gas pressure condition to seal in the gas molecules. These gas-filled beads were then placed in an oven preset at 110° C., allowing the supersaturated gas molecules to try to diffuse out and, thereby, producing micro-porous PS beads or “foamed” beads. These micro-porous beads were then poured onto a suspension of [NGPs+PS+toluene] (Master batch (A)) and stirred for approximately 5 minutes until essentially all beads were coated with a uniform thin film of this suspension. The fluid system was then subjected to a continuous ultrasonic wave treatment (sonification) while the solvent (toluene) was being removed under a ventilated chemical hood. Separated NGP nanocomposite shell-porous PS core spheres were produced after 5 hours of solvent evaporation. EXAMPLE 1 -B From Expandable Coated-Polystyrene Beads [0052] Again, the production procedures for foamed plastics are adapted herein for the preparation of porous plastic beads coated with a nanocomposite shell. Micrometer-sized polystyrene (PS) beads were poured onto a suspension of [NGPs+PS+toluene] (Mater batch (A)) and stirred for approximately 5 minutes at room temperature until essentially all beads were coated with a uniform thin film of this suspension. (One must bear in mind that toluene is a good solvent for polystyrene and, hence, the toluene proportion must be kept to a minimum) The fluid system was then subjected to a continuous ultrasonic wave treatment (sonification) while the solvent (toluene) was being removed under a ventilated chemical hood. The resulting nanocomposite-coated PS beads, after solvent removal, were then subjected to a helium gas pressure of approximately 7 atm and a temperature near 90° C. (inside a pressure chamber) for three hours, allowing helium gas molecules to diffuse through the coating layer into the bulk of PS beads. The chamber was then cooled down to room temperature under a high helium gas pressure condition to seal in the gas molecules. These gas-filled, nanocomposite-coated beads were then placed in an oven preset at 110° C., allowing the supersaturated gas molecules to try to diffuse out (beads being expanded) and, thereby, producing nanocomposite shell-micro-porous PS core spheres or “structural foamed” beads. It was surprising to observe that these spheres have a solid, non-porous skin or shell layer in which nano-scaled graphene platelets were bi-axially oriented tangentially to the sphere, or perpendicular to the radial direction of the bead. This bi-axial orientation appears to have been caused by the bead expansion operation, which biaxially stretched the material in the coating layer (both the polymer chains and reinforcement platelets were stretched or re-orientated), much like a balloon was blown. This bi-axial orientation of both the PS chains and the nano platelets significantly enhanced the strength of the shell structure on these otherwise porous beads (cores), as evidenced by the much improved crush strength as compared with the materials prepared in Example 1 -A. [0053] Quantitatively, thin films of NGP (20% by volume) dispersed in a high-impact polystyrene matrix were prepared using spin casting. The resulting films, with thickness values ranging from approximately 2 to 25 μm, were cut into small dumbbell-shape specimens for tensile testing. The tensile strengths of these nanocomposites were found to vary between approximately 16,000 (if NGPs were randomly oriented on the thin film plane) and 90,000 psi (NGPs were highly oriented in the tensile loading direction). EXAMPLE 1 -C From Polymer Hollow Spheres [0054] Sub-micrometer polymer hollow spheres prepared from emulsion polymerization were mixed with Master batch (B) (mixtures of NGPs+epoxy resin+curing agent) and slightly diluted with acetone. The mixture was then spray-dried to produce nanocomposite-coated latex hollow spheres. The surface coating, containing epoxy and NGPs, was then thermally cured. EXAMPLE 1 -D Two-Stage Core-Shell Polymerization [0055] A 5-liter round bottomed flask was equipped with paddle stirrer, thermometer, nitrogen inlet and reflux condenser. To 2080 g of deionized water heated to 80° C. was added 5.5 g of sodium persulfate followed by 345 g of an acrylic polymer dispersion (40% solids) with an average particle size of 0.3 micron as the seed polymer. A monomer emulsion consisting of 55.5 g of butyl acrylate, 610.5 g of methyl methacrylate and 444 g of methacrylic acid in 406 g of water and 20 g of sodium dodecyl benzene sulfonate (23%) was added over a 2 hour period. This resulting alkali swellable core is used as the seed polymer for the following reaction: [0056] To an identical 5-liter kettle (now empty) is added 675 g of water. After heating to 80° C., 1.7 g of sodium persulfate followed by 50.5 g (1 part by weight solids) of the above alkali swellable core is added. A monomer emulsion (9 parts by solids) consisting of 110 g of water, 0.275 g of sodium dodecylbenzene sulfonate, and a monomer mixture of 20% butyl methacrylate, 75% methyl methacrylate and 5% methacrylic acid (plus a 10% NGPs by weight with respect to the final dry polymer content) is then added over a 2 hour period to prepare an intermediate reactive mixture. This intermediate mixture is then subjected to treatments of swelling with KOH, further polymerization, and formation of voids, as follows: To a 5-liter flask fitted with reflux condenser, nitrogen inlet and padding stirrer is added 989 g of the intermediate mixture. The reactor is heated to 85° C. and 60.9 g of 10% KOH is added for swelling purpose. The mixture is stirred at 85° C. for 30 minutes and 1.0 g of sodium persulfate is added followed by the addition of a monomer emulsion consisting of 243 g of water, 3.3 g of 23% sodium dodecyl benzene sulfonate and 576 g of styrene over a 1.5 hour period. The sample is heated at 85° C. for 15 minutes and cooled to room temperature. The hollow core sizes of the resulting particles (approximately 2.4 μm), when dried, are approximately in the range of 1.2-2.0 μm. EXAMPLE 2 -A Polymer-Clay Nanocomposite-Coated Porous Polystyrene Beads [0057] The procedure was similar to that in Example 1 -A, except that NGPs were replaced by nano clay platelets of comparable volume fraction. EXAMPLE 2 -B Polymer-Clay Nanocomposite-Coated Porous Polystyrene Beads [0058] The procedure was similar to that in Example 1 -B, except that NGPs were replaced by nano clay platelets of comparable volume fraction. The degree of bi-axial orientation of clay platelets was to a slightly lesser extent as compared with that of NGPs. EXAMPLE 2 -C From Hollow Glass Spheres [0059] Sub-micrometer hollow glass commercially available were mixed with a mixture of [NGPs+epoxy resin+curing agent] and slightly diluted with acetone. The mixture was then spray-dried to produce nanocomposite-coated hollow glass spheres. The surface coating, containing epoxy and NGPs, was then thermally cured. [0000] D. Hydrogen Release and Supply [0060] Although some glass and ceramic hollow spheres of sufficiently small sizes (e.g., <1 μm) may exhibit relatively high strengths (e.g., up to 10,000 psi) and their strengths can be further enhanced with a nanocomposite coating as herein disclosed, the release of hydrogen through hollow glass or ceramic spheres at a desired rate to meet the needs of an operatingl fuel cell has presented a great technical challenge. This is largely due to the low gas permeability of high-strength glass or ceramic materials and their high glass transition or softening temperatures. Heating of gas-pressurized hollow glass spheres to a sufficiently high temperature (close to their glass transition temperatures (Tg), normally higher than 500°-900° C.) is required in order to have a sufficiently high hydrogen release rate. This would consume great amounts of energy and would take a long time to reach such high temperatures, making it impractical to use these hollow glass spheres to store and supply hydrogen to a fuel cell or a combustion engine. [0061] By contrast, polymers (including plastics, rubbers, etc.) have a much lower glass transition temperature or softening point, typically from well below room temperature upward to 300° C. Amorphous plastics typically have a glass transition temperature from slightly above room temperature to below 200° C. (e.g., polystyrene has a Tg= 26 100° C.). The hollow spheres or shell-porous core structures made out of these materials would be ideal materials as far as hydrogen release and supply is concerned. Unfortunately, unreinforced plastics and rubbers exhibit relatively low strength and, hence, are not suitable for high-capacity hydrogen storage. [0062] The presently invented nanocomposite shell-core compositions with a hollow core or porous core overcome the above technical difficulties in the following manners: On one hand, the nanocomposite shell dramatically improves the strength of the otherwise relatively low-strength plastics (plastics typically being lower in strength by 3-10 times as compared to glass). The nanocomposite shell actually is stronger than a glass material by a factor of 5-10. The presence of nano-scaled platelets not only increases the strength of the shell, but also reduces the gas permeability through the shell, thereby significantly enhancing the hydrogen storage capability at a temperature lower than Tg of the plastic matrix (e.g., at room temperature for polystyrene). On the other hand, the low Tg's or softening points of the plastic or rubbery core materials and the matrix resin in the nanocomposite shell make it possible (and not too energy-consuming) to rapidly heat up the shell-core compositions to release the hydrogen. We have found that the hydrogen release rate is normally low at room temperature and up to approximately 10-20 degrees Celsius below the Tg of a plastic. Within 10-20 degrees of the Tg (the temperature range varying with the plastic type), appreciable hydrogen release rates commence with the rates increasing rapidly with further temperature increases. The rate gradually reaches a plateau 10-20 degrees above the Tg. For instance, with a Tg of 100° C. as indicated in FIG. 5 , polystyrene-based core wall or shell structure will have a processing window of approximately 25 degrees (from 90° C. to 115° C.) in which one can adjust the hydrogen release rate to meet the potentially changing needs of an operating hydrogen fuel-consuming device like a fuel cell. [0063] With the presently invented nanocomposite shell-core compositions, hydrogen may now be safely and conveniently stored in a light-weight container, which can feed hydrogen on demand to a fuel cell. As shown in FIG. 6 , a light-weight container 60 , made out of a plastic or reinforced plastic, is used to contain nanocomposite shell-core compositions (micro-spheres) 61 . The nanocomposite shell-core compositions were pre-filled with hydrogen gas at a high pressure, but the interior space 63 of the container 60 does not have to be at a high hydrogen pressure. It just has to be filled with hydrogen, displacing other types of gases such as nitrogen and oxygen outside the container. However, one may choose to fill the empty space between core-shell spheres with hydrogen gas up to a safe pressure in order to further increase the total hydrogen storage capacity of the system. The container 60 preferably has optional openings 62 , 64 to allow for refilling of gas-filled micro-spheres and removal of spent micro-spheres, which are to be refilled with hydrogen perhaps at a different location. A safety valve 66 is recommended for preventing any possibility of over-pressure in the container. A conduit 74 with a control valve 76 may be used to transport hydrogen gas, on demand, from the container 60 to a gas diffusion channel 72 on the anode side of a fuel cell 70 . [0064] In order to begin the operation of a fuel cell 70 , one may choose to turn on the control valve 76 to allow for some hydrogen to flow into the gas diffusion channel 72 . The power generated by the fuel cell may be partially fed back to a heating or energizing system (e.g., comprising a control 80 and a heat/energy source 82 ) to heat up the gas-filled micro-spheres 61 inside the container 60 . This source 82 may be, as an example, a heater or an infrared lamp. It may be noted that the operation of a hydrogen-air fuel cell generates a significant amount of heat as an electrochemical reaction by-product. This amount of heat, which is known to be capable of raising the temperature of a proton exchange membrane fuel cell above 100° C., typically becomes wasted in a conventional fuel cell. However, in the presently invented method, this heat can be transferred back to the container 60 as a major auxiliary heat source. This will make the presently invented system a very energy-efficient one. The majority of the power generated by the fuel cell will be utilized by an external electrical appliance such as a personal computer; only a small amount of power will be drawn to help release the hydrogen. [0065] Hence, another preferred embodiment of the present invention is a container that contains therein a plurality of nanocomposite-based core-shell compositions to store gas molecules inside these compositions. The container is equipped with means for releasing the gas molecules. [0066] Still another embodiment of the present invention is a low power-consumption method for releasing the hydrogen from the shell-core compositions inside a container at a controlled rate. Light of specific wavelength ranges (e.g., infrared, IR) may be used to heat up the micro-spheres to release the hydrogen. The IR light intensity may be adjusted to control the hydrogen flow rate. Alternatively, a heater or a hot air blower may be used to heat the micro-spheres to reach a temperature withing the range of (Tg<20 degrees) and (Tg+20 degrees), but preferably in the range of (Tg−10 degrees) and (Tg+10 degrees), where Tg is the glass transition temperature or a softening point of a shell matrix resin or core material. A Tg no greater than 150° C. is preferred. A hydrogen-based combustion engine can also draw the needed hydrogen fuel from the presently invented system. Optionally, a rechargeable battery may be used to help initiate the operation of the fuel cell by providing an initial amount of the heat to help release the hydrogen. This battery can be readily recharged once the fuel cell is in full operation.

A core-shell composition for gas storage, comprising a hollow or porous core and a shell comprising a nanocomposite. The nanocomposite is composed of an exfoliated layered filler dispersed in a matrix material, which provides high mechanical strength to hold a high pressure gas such as hydrogen and high resistance to gas permeation. Alternatively, the porous core may contain a plurality of cavities selected from the group consisting of shell-hollow core micro-spheres, shell-porous core micro-spheres, and combinations thereof. These core-shell compositions, each capable of containing a great amount of hydrogen gas, can be used to store and feed hydrogen to fuel cells that supply electricity to apparatus such as portable electronic devices, automobiles, and unmanned aerial vehicles where mass is a major concern. A related method of storing and releasing hydrogen gas in or out of a plurality of core-shell compositions is also disclosed.

FIELD OF THE INVENTION The disclosed device relates to a self adjusting self tightening wrench. More particularly it relates to a wrench with a handle and rotationally pivoting jaw member which form a substantially parallel grip on objects throughout the range of rotation of the jaw member which will accommodate an infinite number of sizes of objects to be rotated by the wrench between the wrench's minimum and maximum mouth openings. BACKGROUND OF THE INVENTION Adjustable wrenches in the past have generally been of a type which laterally translates a moveable jaw member away from and toward and fixed working surface on the wrench handle. By translating the jaw member further away, using a geared mechanism, the distance between the fixed working surface on the handle and the moveable working surface of the jaw member may be increased to a finite distance. This allows such adjustable wrenches to accommodate a range of sizes of bolts, pipes, nuts, or other objects needing rotational movement. Similar adjustable pliers allow for the increase of the dimension between the working surface of the fixed handle and the pivoting jaw member by slidable engagement of cooperatively engageable tracks on both the handle and the jaw member. This again allows for adjustment of the distance between the working surface of the jaw member and the handle to be adjusted to accommodate the object being gripped for rotation. Such conventional adjustable wrenches do however provide for a continuous and automatic adjustment of the force or tightness of the “grip” which the wrench had on a work piece. Consequently, because the adjustable wrench was not sized to the object being worked on, slippage occurred of the wrench on the object being turned resulting in a “knuckle buster” which has been a constant source of aggravation to the user of such wrenches. Further, such adjustable wrenches generally require some movement of an adjusting mechanism by the user which requires two hands and a reasonable high amount of dexterity. As such, there is a pressing need for an easily functioning adjustable wrench. Such a wrench should automatically adjust to the object placed between its jaws. Such a wrench should not slip when twisted and should ideally increase the force of the grip on the object being rotated between the jaws when the force on the wrench is increased. Further, such a wrench should maintain relatively equal pressure on both sides of the object being twisted to maximize grip and minimize distortion of the object of the wrench's force. SUMMARY OF THE INVENTION The above problems, and others are overcome by the herein disclosed automatically adjusting self tightening wrench. The device is composed of a handle and rotating jaw member having a gripping surface area on a distal face of the jaw member. The jaw member is rotationally attached to the handle at the opposite end from the area to be gripped by the user. The rotation of the jaw member is generally about a pin or axle used to secure it to the distal end of the handle. In the current best mode, the jaw member rotates about the pin and into a slot grooved into the handle just below the pin thereby allowing the jaw member to rotate on the pin with the attachment end of the jaw member rotating into the slot. The gripping surface area of the jaw member at an angle substantially normal to the center axis of the elongated handle when the jaw member is in a fully biased position rotated to its closest point to the work surface formed on the end of the handle. The handle gripping surface is formed on a working face portion shaped like an arc. When the jaw member rotates about the axle, the jaw gripping surface area of the jaw member becomes increasingly distant from the handle gripping surface formed on the arced face of the handle because both circles have different center points. This increase in distance allows the device to accommodate larger and larger objects between the jaw gripping surface and the handle gripping surface as the jaw member is rotated to increase the distance of the planar face of the jaw member and the jaw gripping surface thereon, away from the handle gripping surface on the handle face. A biasing means such as the spring shown in the current best mode of the device, is in communication at one end with the static handle and at the other with the rotating jaw member and biases the jaw gripping surface area on the planar face of the jaw member toward the handle gripping surface formed on the arcing face of the handle, at all times. This allows the device to immediately self adjust to the diameter of the object placed between the gripping surface on the face of the jaw member and the jaw gripping surface on formed on the face of the handle opposite the end to be held by the user. Unique to the disclosed device is the maintaining of generally parallel contact between gripping surfaces no matter what the size of the object inserted therebetween. This is accomplished by the arc shape forming the working face on the handle on which the handle gripping surface resides. By forming the working surface in an arc, and forming the jaw gripping surface on a generally planar face that is normal to the center axis of the handle at its closest position, when the jaw is rotated about the axle pin on the handle, a generally parallel contact of both gripping surfaces on the object therebetween is maintained. As can be seen, the actual surface area of an object touching the arced surface of the gripping end of the handle is very small thus providing the generally parallel contact between both gripping surfaces at all points in the rotation of the jaw member. In the current best mode, teeth or a gnarled surface would be provided on both the arced face of the handle and the planar face of the jaw member. This allows for a better frictional connection between the object being rotated between the jaw member and the handle during use. The formed teeth or other frictionally engaging surface are best angled to allow maximum grip when the wrench is torqued in the direction of object rotation which occurs when the gripping end of the handle is forced toward mouth opening formed between the jaw member and the arced handle face. The arrangement of angling the teeth would also allow the device to slip when the wrench is pulled in the opposite direction of intended rotation which occurs when the hand grip end of the handle is pulled away from the mouth opening. This allows the device to slip in one direction and grip progressively harder in proportion to the force applied in the other direction. Finally provided to make the device even more user friendly is the thumb grip on the exterior surface of the jaw member. This area of the jaw member is notched or otherwise surfaced for easy frictional engagement of the user's thumb or finger with the jaw member. This allows the user, with only one hand, the place the mouth opening of the device over the object for rotation and then to pull open the jaw member still using one hand by simply pressing with the thumb or finger on the thumb grip to overcome the force of the biasing means and remove or readjust the device from the object being turned. Accordingly, it is the object of this invention claimed herein to provide a simplified and easy to use self adjusting wrench which will tighten its grip on the object being turned as the force applied to the handle is increased. It is another object of this invention to supply such a self adjusting wrench that will relax its grip on the object being turned and slip when pulled in the opposite direction of intended object rotation. It is still another object of this invention to provide such a self adjusting wrench which has a biased jaw allowing the user to use the device with only one hand and secure it over the object to be turned. It is a still further object of this invention to provide an easy thumb release on the jaw of the device such that the user can release it from engagement with the object to be turned still using one hand and the thumb to overcome the biasing means. It is yet another object of this invention to provide a self adjusting wrench which by using a curved gripping surface on the handle and planar surface on the jaw maintains a substantially parallel engagement upon the object being turned by the wrench and substantially equal imparting of force by each working face upon the object turned. Further objectives of this invention will be brought out in the following part of the specification, wherein detailed description is for the purpose of fully disclosing the invention without placing limitations thereon. BRIEF DESCRIPTION OF THE DRAWING FIGURES The accompanying drawings which are incorporated in and form a part of this specification illustrate embodiments of the disclosed processing system and together with the description, serve to explain the principles of the invention. FIG. 1 depicts a side view of the disclosed self adjusting wrench showing it with the jaw gripping surface in the closest position to the handle gripping surface. FIG. 2 depicts a side view of the disclosed self adjusting wrench showing the jaw gripping surface of the jaw member in the position furthest from the jaw gripping surface of the handle. FIG. 3 shows a side view of the device with the handle cut away to reveal the interior cavity for travel of the jaw member on the axle pin and the biasing means. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1–3 preferred embodiments of the disclosed device 10 with FIG. 1 depicting a side view of the disclosed self adjusting wrench device 10 . The device 10 features a handle 12 having a grasping end 14 and a working end opposite the grasping end 14 . A rotatingly mounted jaw member 18 is mounted to the handle 12 at th working end 16 using a pin 20 or axle which communicates into the handle 12 and jaw member 18 and attaches the jaw member 18 in rotational engagement with the handle 12 about the working end 16 of the handle 12 . On the working end 16 of the handle 12 arc shaped handle working face 22 is formed and on this handle working face 22 a handle gripping surface 24 is formed. The current best mode of the device 10 features the handle working surface 22 in an arc and forming the jaw gripping surface 26 on a generally planar face 28 of the jaw member 18 opposite the handle working face 22 . By forming the jaw gripping surface 26 on a substantially planar jaw planar face 28 and rotating that gripping surface 26 around the arced handle gripping surface 24 the object 30 which is to be rotated is gripped at two substantially parallel contact points no matter what rotational position the jaw member 18 and jaw member gripping surface 26 is located in relation to the handle gripping surface 24 on the arced handle working face 22 . This curve or arc of the handle working face 22 and the handle gripping surface 24 thereon, combined with the rotation of the jaw gripping surface 26 around it during rotation of the jaw member 18 thus provides substantially parallel contact points on both sides of a gripped object 30 no matter what point the jaw member 18 has rotated to accommodate the size of the object 30 . This of course substantially equalizes the pressure imparted to both sides on which the object is gripped by the device 10 . The rotation of the jaw member 18 is as noted provided by the axle formed by the pin 20 used to secure the jaw member 18 to and in rotational engagement at the working end 16 of the handle 12 . In the current best mode, the jaw member 18 rotates about the pin and into a slot 32 grooved into the handle 12 just below the pin 20 providing a relief into which one end of the jaw member 18 may rotate into on the handle 12 . Automatic adjustment of the device 10 to the size of the object 30 is provided by the rotation of the jaw member 18 about the pin 20 . As the jaw member 18 rotates, the jaw gripping surface 26 on the jaw planar face 28 follows a circular path around the pin 20 but becomes increasingly distant from the handle gripping surface 24 formed on the arced handle working face 22 . This resulting increase in distance allows the device to accommodate larger and larger objects 30 between mouth 34 formed between the jaw gripping surface 26 and the handle gripping surface 24 . The maximum size of the mouth 34 so formed would be determined by the maximum distance of the jaw gripping surface 26 from the handle gripping surface 24 and also by changing the angle of the elbow 36 where it intersects the first jaw member strut 36 and angles back on the second jaw member strut 38 to determine the position of the jaw planar face 28 in relation to the handle working face 22 . Increasing the angle of the elbow 36 would increase the smallest size of the mouth 34 and the resulting largest size of the mouth depicted in FIG. 3 . Also seen in FIG. 3 are the two substantially circular paths 51 and 52 followed by the handle working face 24 and the jaw planar face 28 respectively. These offset circular paths followed by both surfaces thus increase and decrease the distances between the two allowing for the size of the mouth 34 to increase and decrease for the size of the object 30 . A means to bias the jaw gripping surface 26 toward the handle gripping surface 24 is provided in the current best mode by the spring shown in the current best mode of the device 10 . The spring 42 also in the current best mode has an elbow shape and is sized to reside inside the slot 32 during use. As depicted the spring 42 is attached inside the slot 32 at a first end using a set screw 44 and to the jaw member 18 at the opposite end in frictional engagement with an aperture 46 . This type of spring bends at the spring elbow 46 and therein biases the jaw member 18 and affixed jaw gripping surface 26 area on the jaw planar face 28 under biased force toward the handle gripping surface 24 formed around the arced handle working face 22 . This bias allows the device to immediately self adjust to the diameter of the object 30 placed in the mouth 34 by biasing the jaw member 18 back toward the handle gripping surface 24 at all times. It also provides the ability to used the device with only one hand by simply engaging the object to be turned into the mouth and rotating the handle 12 toward the mouth side of the device 10 . In the current best mode, teeth 48 or an otherwise gnarled surface would be provided on both the arced handle gripping surface 24 and the jaw planar face 28 of the jaw member 18 . These teeth 48 allow for a better frictional connection between the object 30 being rotated and the gripping surfaces on the jaw member 18 and the handle 12 during use. The formed teeth 48 are best angled to allow maximum grip when the wrench is torqued in the direction of object rotation which occurs when the gripping end 14 of the handle 12 is forced toward mouth side of the handle formed between the jaw member and the arced handle face. The arrangement of angling the teeth 48 would also allow the device 10 to slip when the wrench is pulled in the opposite direction of intended rotation which occurs when the griping end 14 of the handle 12 is pulled away from the mouth opening. This allows the device to slip in one direction and grip progressively harder in proportion to the force applied in the other direction. The curved surface of the hand gripping surface 24 tends also to turn into the object being held grabbing it tighter as more force is applied. Finally, in the current best mode of the device 10 a biasing release is provided to make the device even more user friendly and useable by one hand. This is provided by the thumb grip 50 on the exterior surface 52 of the jaw member 18 and could be surfaced with teeth 48 or other frictional engagement style surfacing. The thumb grip 50 allows the user, with only one hand, to place the mouth 34 opening of the device over the object 30 for rotation and then to pull open the jaw member 18 still using one hand by simply pressing with the thumb or finger on the thumb grip 50 to overcome the force of the biasing means and remove or readjust the device 10 from the object being turned. While all of the fundamental characteristics and features of the automatically adjusting self tightening wrench have been shown and described, it should be understood that various substitutions, modifications, and variations may be made by those skilled in the art, without departing from the spirit or scope of the invention. Consequently, all such modifications and variations are included within the scope of the invention as defined by the following claims.

A self-adjusting wrench having a handle and a jaw member rotationally attached thereto. A smoothly curved handle face opposes a planar face on the jaw member which adjusts for distance from the curved handle face by following a generally circular path around a pinned attachment of the jaw member to the handle. A spring or similar biasing device continuously urges the jaw member toward the handle thereby making the device self adjusting to the size of the object placed between the jaw member and the curved handle surface.

BACKGROUND The invention relates to the signalling of a high-voltage aerial line or more generally an aerial transmission line by a signalling device in the context of air safety. The invention may be used in the field of the prevention of accidents during the day and/or at night of birds owing to impacts with transmission lines. Without being limited to these materials or these values, standard transmission cables of high-voltage aerial lines most often comprise an aluminium alloy and most often have diameters of from 15 to 32 mm, sometimes up to 44 mm. Those cables are relayed over long distances by pylons which are generally spaced apart by approximately one hundred meters from each other. The voltages used vary according to the countries and needs, for example, between 63 and 90 kV for urban distribution or regional distribution and between 110 and 220 kV for regional exchanges. Values approaching 400 kV and more may be reached in some connections with very high voltage. Modern so-called “ultra-high-voltage” lines have been tested up to at least 1200 kV. Unlike the low-voltage lines which are relatively close to the ground, at a height of approximately ten meters, high-voltage lines are installed at several tens of meters from the ground, often at a height between 30 and 50 meters from the ground as, for example, in France, but may be positioned at greater heights in accordance with their geographical location and their voltage level, reaching up to approximately 350 m for the tallest pylons. Therefore, those lines are at heights which may interfere not only with low trajectories of aircraft or gliders but also, for example, with the flight of migrating birds or the very rapid descending or ascending movements carried out by hunting raptors. Very-high-voltage lines of 225 or 400 kV and more have problems connected with health impacts, impacts on the landscape, tourism, habitat but also particularly ecological problems connected with collisions and electrocution of large numbers of birds which are regularly seriously injured, or killed, each year if they do not avoid those obstacles. In some regions with a high density of migratory birds, the number of victims may be as high as several thousands of victims/km/year, most often large birds. This problem is known to electricity transport companies and various associations, in particular associations for the protection of birds. The most effective solution would be to bury the electrical lines but this solution has the disadvantage not only of being difficult but also of having to modify a very large proportion of the existing national and international electrical networks, and may therefore possibly be envisaged only over the very long term. Therefore, different types of signalling systems have been developed and are known in the prior art for signalling the high-voltage lines to aircraft and/or to birds. Each known system addresses similar obstacles but without succeeding in simultaneously overcoming them. For example, document U.S. Pat. No. 4,885,835 discloses a spherical signalling device which comprises two hollow hemispheres of plastics material which surround a section of an aerial line in the context of signalling intended for aircraft pilots. The hemispheres are screwed together on the ground over approximately half of their perimeter, then the non-screwed portion is moved apart by an operator so as to place the hemispheres around a section of high-voltage line. The hemispheres of plastics material are subsequently screwed over the remainder of their perimeter. The disclosed device further comprises an attachment system using cabling which is intended to be wound around the high-voltage line. This type of system is not particularly well suited to very-high-voltage lines of 400 kV or more, whose cables can become heated to temperatures of up to from 80 to 250° C. That system is also not suitable for visibility at night, winter conditions or foggy conditions. Other solutions are known in the prior art for signalling aircraft but are still at the experimental stage such as, for example, red-coloured counterweights which are bolted to the cables, or systems of wires twisted around the high-voltage cable. Even if some systems operate on cables of 400 kV and more, the visibility for birds remains ineffective, some systems are far too heavy to be deployed over the whole of a line, or they need tools which are too heavy and impractical for their assembly from a helicopter. The materials used further have problems of ageing, in particular involving the changing of colour, so that those devices are not identifiable by birds, in particular under conditions of fog, snow and/or darkness, and deteriorate over time. Some solutions are known specifically for signalling intended for birds such as, for example, a helical system in which the devices of helical form and variable diameter are wound around the transmission line. Those helical systems weigh approximately 700 g each and are composed of plastics material, typically a thermoplastic polymer such as PVC, and are red and white in colour. In the prior art, such a helical system comprises two helixes which have a wider diameter than the others and which are visible to birds. The projected surface-area per unit is approximately 16800 mm 2 for a total exposed surface of 0.12 m 2 when 7 helical devices are arranged on cables between two successive pylons which are spaced apart by approximately 120 m, each device being spaced apart from the following or preceding device by approximately 15 m. This system is currently one of the most deployed on medium-voltage lines (up to 90 kV). Another system which is known from the prior art and which is used, for example, in Sweden, involves suspending a device resembling a bi-coloured card. In both cases, use on high-voltage lines cannot be envisaged owing to the temperatures reached, but in particular owing to the need for insulation products to be set to potential. This is because an insulation material positioned on a high-voltage line generates potentials known as “floating” potentials which result in the production of partial electrical discharges, generally referred to as the “corona effect”, between the insulation components and the air. Those discharges destroy the insulation members, to the extent that they may be totally burnt, without taking into account the drops in voltage following that phenomenon, which may therefore go so far as to bring about a reduction in the voltage at the end of production and therefore potentially a reduction in the transit capacity. Extended use for signalling lines to birds also cannot be envisaged owing to the deterioration, in particular the loss of colour, owing to exposure to UV radiation. Those systems further have disadvantages involving durability owing to embrittlement of the materials used. The systems known in the prior art also have the disadvantage of not being suitable for use at night or during atmospheric influences and are particularly unsuitable for fog, snowy or icy conditions. Therefore, there is a need to provide a signalling device which can be readily installed on a high-voltage aerial line. Given the dimensions, in particular the height, of the pylons supporting the lines and therefore the lines themselves, the installation of the signalling devices is generally carried out by an operator who is suspended from a helicopter, and each operation for installing a signalling device is therefore difficult and involves risks for the operator. The signalling devices known from the prior art are distributed over the cables of high-voltage lines between each pylon so as to be visible to birds and/or aircraft pilots. Given the length of each cable, therefore, it is necessary to use a plurality of devices per cable in order to allow the identification of the entire length of a cable between two successive pylons. The weight of the signalling devices is therefore also important in order not to increase the mechanical stresses in the cables and therefore there is also a need to provide signalling devices which are quite light in order to be able to be installed in large numbers along a cable between two successive pylons of an aerial transmission line. As mentioned above, it is also necessary to provide a device capable of operating equally well on low-voltage, medium-voltage, high-voltage or very-high-voltage lines, or even ultra-high-voltage lines. In the context of preventing accidents involving birds but also of air safety in regions around airports, it is also necessary to provide a signalling device which is effective both during the day and at night, and for all meteorological conditions, in particular during hazy weather and under conditions of snow and/or frost. SUMMARY Therefore, an object of the present invention is to provide a signalling system for aerial transmission lines which is suitable particularly but not exclusively for high-voltage lines of at least 400 kV or more, whilst taking into account the problems mentioned above. This object is achieved with a signalling device for an aerial transmission line comprising two signalling elements which are configured to be mounted one against the other around a conductor portion of the transmission line, in which at least one of the two signalling elements comprises at least partially an outer signalling coating in the context of air safety, and which device is characterised in that the two signalling elements are at least partially electrically conductive and at least one of the two signalling elements comprises a clamping means which is configured to clamp the conductor portion of the transmission line. The signalling device according to the invention comprising materials which are at least partially electrically conductive may therefore be suitable for contact with conducting cables which transport high voltages and which may become heated up to high temperatures, including temperatures in the order of 250° C. or more. For example, the two signalling elements may be constructed from plastics materials with a metal coating, or completely from aluminium or any other semi-conductor, metal, conductive material or light alloy. A device according to the invention may therefore be mounted on lines at 400 kV or more, given that the conductivity of the materials used may be adapted in accordance with the voltage of the line. Materials which are at least partially conductive further allow a Faraday cage to be formed around the portion of conductive cable of the transmission line, which prevents the problems connected with the corona effect. A clamping means which clamps a conductive cable of the line, that is to say, takes the cable of the transmission line in a sandwich-like manner between the two signalling elements, allows retention and assembly which is simplified and advantageous with respect to the assemblies known from the prior art, and can therefore be adapted to fixing operations which are carried out via helicopter. The term “outer signalling coating visible to pilots and/or birds” is intended to be understood to mean that the device according to the invention comprises an outer coating which is visible to all types of birds and/or pilots, for example, pilots of aircraft, gliders, helicopters, or more broadly pilots of motorised or non-motorised flying devices. An outer coating may be selected so as to be visible to birds and/or pilots, for example, using one or more bright colours and with a strong contrast in relation to the ground. The colour orange or any colour included in a range from red to orange is, for example, identifiable by pilots and birds and contrasts with the majority of ground types, which advantageously allows the lines to be marked, in particular with regard to the dives carried out by hunting raptors if the colour orange is at least partially on the upper portion of the signalling device in relation to the ground. Preferably, the two signalling elements may be substantially hemispherical. The generally spherical shape allows a reduction in the adhesion of snow in relation to the shapes used in the prior art for signalling devices intended for birds. The hemispheres may advantageously be hollow which allows, on the one hand, the weight of the device to be reduced when it comprises a metal material and, on the other hand, the production of an internal space which is suitable for the arrangement of the clamping means. Advantageously, each of the signalling elements may comprise at least two diametrically opposed holes which are configured to surround the conductor portion of the transmission line and to ensure the flow of air in the signalling device. That configuration is advantageous in the case of use on high-voltage or very-high-voltage lines, in which the temperature of the cables reaches 80° C., or from 200 to 250° C., respectively. The conductor portion clamped in the signalling device releases the heat inside the device, in particular in the case of very high-voltage or ultra-high-voltage lines. A ventilation system comprising diametrically opposed holes surrounding the cable allows air to flow along the entire portion of the cable contained inside the device. Preferably, one of the signalling elements may further comprise two bars, in particular two substantially parallel bars, so that the clamping means is arranged on at least one of the two bars. In the case of a hollow device, an internal structure of at least one of the signalling elements allows an increase in the resistance of the device, for example, with respect to bending or deformations owing to the vibrations caused inter alia by the wind. An internal structure which comprises two parallel bars which connect substantially diametrically opposed locations, in particular which connect the ends of ventilation holes where present, allows the device generally to be reinforced. For example, in the case of a substantially spherical device, the bars may strengthen the device axially. Preferably, the clamping means may comprise a lower clamping element which is fixed to the two bars so as to partially surround the conductor portion of the transmission line and which comprises a lower clamping flange and an upper clamping element which comprises an upper clamping flange which is fixed to one of the two bars and which can be closed by engagement with the other bar so as to surround the conductor portion of the transmission line between the lower and upper clamping elements. In the case of a substantially hollow device which comprises substantially parallel bars which strengthen the overall structure, therefore, a clamping means may advantageously be installed inside the device so as to clamp a portion of the voltage line. A device which allows engagement with one of the parallel bars is advantageous in that it allows simple and rapid positioning, in particular by an operator being suspended from a helicopter. An additional advantage may be that the parallel bars are partially flexible, in particular rigid in the direction of the axis thereof, but radially deformable which makes closure by engagement easier. The upper clamping element may advantageously further comprise a clamping block which is configured to clamp the conductor portion of the voltage line with the lower clamping flange. A clamping means may be improved by the presence of, for example, blocks which allow the cable to be clamped, that is to say, allow it to be received in a sandwich-like manner, in particular by means of a screw which presses a clamping block against the cable held on a support surface and/or another clamping block, in particular inside a substantially hollow device. Advantageously, the two signalling elements may be configured to be mounted one against the other by means of clip-fitting. A simple means for closing the device is a clip-fitting of the two signalling elements, which avoids the use of instruments during assembly. Preferably, the outer signalling coating may comprise at least two colours. A signalling device may therefore comprise a colour on one portion of the device and at least one other colour on another portion of the device. For example, it is advantageous to use a coating which is visible during the day on a portion of the device, combined with a coating which is visible at night. It is also possible to combine, for example, a colour which strongly contrasts with the ground on the portion of the device directed towards the sky and a colour which contrasts strongly with the sky on the portion of the device which is directed towards the ground. In that manner, a bird which is diving towards the ground or which is ascending rapidly from the ground will be warned of the presence of an obstacle in both cases, respectively. Advantageously, the signalling coating may be at least partially photoluminescent. The photoluminescence does not require any individual source of energy and is activated by ambient light. The photoluminescent effect is immediate, durable and does not involve any risk of breakdown. At least a portion of the device may therefore comprise a photoluminescent coating in order to be identifiable at night. In particular, the entire signalling device may be covered with a photoluminescent signalling coating or a photoluminescent layer, which affords an advantage in regions near zones around airports for signalling to aircraft during night-time operations or operations in low light. Advantageously, the signalling coating may comprise at least partially an ice-repellent layer. Various ice-repellent treatments exist on the market and may be used to prevent the formation of ice and/or piles of snow on a signalling device. High-performance nanotechnologies are being developed in the fields of defence and aerospace. Other options involve using coatings which are latex-based, silicone-based or based on polytetrafluoroethylene or PTFE. For example, the PTFE-based treatments have ice-repellent characteristics and satisfactory mechanical, optical and electrical properties for use in the context of signalling for high-voltage lines. In particular, a PTFE-based processing operation does not change the appearance of the surface to which it is applied and may reduce the adhesion of ice to the application surface by up to 80%. This type of treatment is also known for not being subject to ageing which is accelerated during irradiation by UV radiation or during exposure to corrosive acid solutions. The ice-repellent coatings also have hydrophobic properties which allows an application surface to be kept clean during rainy weather, given that the water does not adhere but instead cleans the device in respect of dust which could be deposited there. The visibility of a device which is provided with an ice-repellent and hydrophobic layer may therefore be ensured in a durable manner. A device whose surface is provided at least partially, in particular completely, with such a coating is therefore suitable for prolonged use outdoors. Preferably, the diameter of the signalling device may be in the order of from 200 to 500 mm, in particular in the order of 250 mm. Advantageously, the mass of the signalling device may be in the range from 300 g to 1 kg, preferably the mass may be less than 700 g, in particular in the order of 500 g or less. In particular, in the case of a sphere formed by two hollow hemispheres and an alloy comprising at least aluminium, a hollow sphere having a diameter of approximately 250 mm may be limited to a weight of approximately 500 g or less. This object is also achieved with the method for assembling a signalling device for at least one aerial transmission line, comprising the steps of: providing at least one signalling device as described above; arranging the lower clamping element below a conductor portion of an aerial transmission line; closing the upper clamping element above the conductor portion of the transmission line, clamping the conductor portion of the transmission line between the lower clamping flange and the upper clamping flange; and clip-fitting the two signalling elements together. The advantages set out above in respect of the device according to the invention and all the possible variants and embodiments may be combined in order to obtain more embodiments of the invention. In particular, the different advantageous embodiments according to the invention may be combined and used in the assembly method according to the invention. BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described in greater detail below with reference to illustrative examples of advantageous embodiments which are described with reference to the following Figures, in which: FIG. 1 is an exploded, three-dimensional schematic view of a signalling device for a transmission line according to an illustrative example of an embodiment of the invention; FIGS. 2A-2G show assembly steps of the illustrative device of FIG. 1 on a transmission line; FIG. 3 is an illustrative example of one possible configuration of a plurality of signalling devices according to the invention on aerial transmission lines. Elements which are identical or which have similar functions in the different illustrative examples of embodiments of the invention will be indicated below with the same reference numerals or symbols. DETAILED DESCRIPTION FIG. 1 is an exploded, three-dimensional schematic view of an example of a signalling device 1 for a transmission line according to an illustrative embodiment of the invention. FIGS. 2A to 2G illustrate different steps of the assembly of such a device 1 on a conductive cable 2 of a transmission line, for example, a high-voltage aerial line. According to one embodiment of the invention, the signalling device 1 illustrated in FIG. 1 comprises two signalling elements 3 , 4 which are configured to be mounted one against the other so as to clamp the conductive cable 2 of a transmission line, for example, a high-voltage aerial line. In the illustrative example of FIG. 1 , the two signalling elements 3 , 4 may be composed of a plastics material which is integrally covered with a metal or a metal alloy. Preferably, in the example of FIG. 1 , the two signalling elements 3 , 4 are composed of aluminium or a metal or light metal alloy and are hollow hemispheres having a geometry which is substantially mutually identical. However, the signalling elements 3 , 4 may have a different geometry from each other, in particular not necessarily a spherical geometry. In the case of hemispheres 3 , 4 which comprise aluminium, it is possible to obtain a relatively light signalling device 1 which weighs approximately 500 g or less, which makes it quite light for being applied to high-voltage lines. The perimeter of each hemisphere 3 , 4 comprises an annular element 17 , 18 , of which the annular element of the upper hemisphere 3 relative to the cable 2 protrudes slightly more in relation to the surface 12 of the upper hemisphere 3 than the annular element 18 does from the surface 13 of the lower hemisphere 4 so as to be mounted on the annular element 18 of the lower hemisphere 4 . The two signalling elements 3 , 4 also each comprise two holes 14 , 14 ′, 15 , 16 of substantially semicircular form which are diametrically opposed and configured so as to receive the cable 2 in the direction of the length thereof. The second hole 14 ′ of the upper hemisphere 3 is not visible in FIG. 1 but is diametrically opposed to the hole 14 in a similar manner to the holes 15 , 16 of the lower hemisphere 4 . When the signalling element 3 is mounted on the signalling element 4 , the holes 14 , 14 ′, 15 , 16 form circles around the cable 2 , leaving a space for ventilating the interior of the device 1 . That system is particularly suitable in the case of high-voltage or very-high-voltage lines, whose heat brought about by the transport of the electric current may reach at least 80° C., or from 200 to 250° C., and even higher temperatures, respectively. The holes 14 , 14 ′, 15 , 16 therefore form a transverse ventilation passage along the device 1 , as illustrated in FIG. 2A , in the longitudinal direction of the cable 2 , as illustrated in FIGS. 1 and 2B to 2G , which allows simple and effective ventilation of the interior of the device 1 . The signalling elements 3 , 4 also each comprise two diametrically opposed holes 32 , 33 , 34 , 34 ′. The second hole 34 ′ of the signalling element 3 cannot be seen in FIG. 1 but is diametrically opposed to the hole 34 in a similar manner to the holes 32 , 33 of the other signalling element 4 . Those holes 32 , 33 , 34 , 34 ′ are in the annular elements 17 , 18 of each hemisphere 3 , 4 and have a diameter less than the width of the annular elements 17 , 18 , respectively. The lower signalling element 4 further comprises two identical flexible plates 40 , 43 which each comprise a clip-fit projection 44 , 44 ′; the projection 44 ′ of the plate 40 cannot be seen in FIG. 1 . The plates 40 , 43 are fixed to the interior of the annular element 18 so as to allow the clip-fit projections 44 , 44 ′ to pass through the holes 32 , 33 . In that manner, the upper signalling element 3 is clip-fitted to the clip-fit projections 44 , 44 ′ by means of the holes 34 , 34 ′ of the annular element 17 thereof in the final position as illustrated in FIG. 2G . According to an embodiment of the invention, at least one of the two signalling elements 3 , 4 , in this instance the lower hemisphere 4 , comprises two parallel bars 6 , 7 which are partially flexible and which allow the aluminium chassis of the lower signalling element 4 to be strengthened. In that manner, if the device 1 illustrated in FIG. 1 comprises aluminium, the torsions and deformations caused by heavy exposure to the wind may be avoided or at least lessened in relation to a hollow element which does not comprise those support bars. According to an embodiment of the invention, at least one of the two signalling elements 3 , 4 , in this instance the lower element 4 , comprises a clamping means 5 which is intended to clamp the cable 2 in order to maintain the device 1 mounted on a transmission line, in particular a high-vciltage line. The different elements which constitute the clamping means 5 may be of metal or composed of a metal alloy which may be adapted in accordance with the type of line and the heat released. The clamping means 5 comprises a lower clamping element 8 which comprises a lower clamping flange 9 , on which the cable 2 rests during installation as shown in the illustration of FIG. 2B , and which is fixed, on the one hand, to the first parallel bar 6 by a lug 19 and, on the other hand, to the second parallel bar 7 by means of two lugs 20 , 21 having an oblong hole. The lugs 20 , 21 having an oblong hole are substantially fixed in position in the longitudinal direction of the bar 7 by recesses 45 , 46 , in which stop rings 36 , 38 are placed. The geometry of the assembly of the clamping means 5 is such that it is arranged substantially around the centre of the sphere formed by the two signalling elements 3 , 4 , as illustrated in FIGS. 2A to 2G . The clamping means 5 also comprises an upper clamping element 10 which itself comprises an abutment plate 24 which is retained on the parallel bar 6 by means of two lugs 22 , 23 , whose movement is limited, as for the lugs 20 , 21 , in the longitudinal direction of the bar 6 by recesses 41 , 42 in the bar 6 , in which stop rings 35 , 37 are placed. The abutment plate 24 of the upper clamping element 10 also comprises a hooked lug 25 which is intended to engage with the parallel bar 7 in order to surround, in particular clamp, the cable 2 in the clamping means 5 , as illustrated in FIGS. 2A to 2C . In particular, FIG. 2A illustrates the lower signalling element 4 with the clamping means 5 being mounted on the parallel bars 6 , 7 in the open position. FIG. 2B illustrates the same state, with a cable 2 pressing on the lower clamping flange 9 . Finally, FIG. 2C illustrates the closure of the hooked lug 25 on the bar 7 , thereby surrounding the cable in abutment against the lower clamping flange 9 , and between the lugs 19 , 20 , 21 , 22 , 23 , 25 , and the abutment plate 24 . The oblong hole of the head of the lugs 20 , 21 having an oblong hole allows the partial radial flexibility of the parallel bar 7 to be used during the engagement of the bar 7 by the hooked lug 25 as illustrated in FIG. 2C . The hooked lug 25 thereby repels the bar 7 , which can be bent in the radial direction and can therefore slide in the holes of the lugs 20 , 21 having an oblong hole, which makes it easier to carry out the engagement operation, in particular for an operator being suspended from a helicopter. The dimensions and the geometry of the holes 14 , 14 ′, 15 , 16 , the arrangement of the parallel bars 6 , 7 and the dimensions of the clamping means 5 can all be adapted to the dimensions, in particular the diameter, of the cable 2 of the voltage line on which the signalling device 1 must be mounted. According to a variant of an embodiment of the invention, the upper clamping element 10 may comprise an upper clamping flange 11 which is configured to clamp the cable 2 with the lower clamping flange 9 . This is the case for the exemplary device 1 illustrated in FIGS. 1 and 2A to 2G . In the illustrative example of FIGS. 1 and 2A to 2G , the upper clamping flange 11 is retained on the upper clamping element 10 by means of a screw 26 having a hexagonal head and a stop ring 39 . In order to make the installation operations easier, in particular for an operator being suspended from a helicopter, the clamping torque of the clamping block 50 of the upper clamping flange 11 is controlled by a meltable head 27 on the hexagonal screw 26 , whose head is received in a hexagonal core 28 of the meltable head 27 . The meltable head 27 also comprises a meltable ring 31 , on which two fins 29 , 30 are arranged. The complete assembly of the clamping means 5 , in particular the upper clamping element 10 comprising the clamping block 11 and the hexagonal screw 26 having a meltable head 27 , can be seen in FIG. 2A before a cable 2 is arranged in the device 1 which is illustrated in FIG. 2B . FIG. 2A shows how the lower clamping element 8 and upper clamping element 10 are arranged on the parallel bars 6 , 7 . The upper clamping element 10 is arranged in a rotatable manner about the bar 6 so that the hooked lug 25 can close the clamping means 5 by engaging with the bar 7 , as in FIG. 2C , once the lower signalling element 4 has been arranged below the cable 2 , as in FIG. 2B . The cable 2 is clamped by the clamping element 5 and, in principle, an installation operator could mount the signalling element 3 in order to finalise the assembly of the signalling device 1 on a transmission line. Therefore, an operator does not need any tools to install a signalling device 1 according to the invention on a cable 2 of a voltage line, which is advantageous in the case of high-voltage lines installed several tens of meters above the ground. After carrying out the steps described above with reference to FIGS. 2A to 2C , the installation operator can subsequently turn the meltable head 27 by means of the fins 29 , 30 in order to press the clamping block 11 against the cable 2 , thereby clamping the cable 2 between the clamping block 11 and the lower clamping flange 9 , as illustrated in FIG. 2D . The meltable head 27 allows the operator to control the torque applied during the clamping action. When the clamping block 11 is in a position against the cable 2 and the operator continues to turn the meltable head 27 of the screw 26 having a hexagonal head, the meltable ring 31 and the fins 29 , 30 become detached from the hexagonal ring 28 of the meltable head 27 and fall on the abutment surface 24 of the upper clamping element 10 , as illustrated in FIG. 2E . This has the advantage that, for an installation operator suspended from a helicopter, there is no moving part which can fall or become detached from the lower signalling element 4 during or after the installation. Therefore, the meltable ring 31 remains secured between the screw 26 having a hexagonal head, the hexagonal ring 28 of the meltable head 27 and the abutment surface 24 . The final step of the assembly subsequently involves clip-fitting the upper signalling element 3 to the lower signalling element 4 by means of the clip-fit projections 44 , 44 ′ of the flexible plates 40 , 43 in the region of the holes 32 , 33 , 34 , 34 ′. This is illustrated in FIG. 2F for the provision of the upper hemisphere 3 and, in FIG. 2G , for the closure of the signalling device 1 thereby forming substantially a sphere which clamps the cable 2 of a transmission line. According to one embodiment of the invention, at least a portion of the outer surfaces 12 , 13 of the signalling elements 3 , 4 comprises a signalling covering which can be identified by birds. In that manner, in the illustrative example of FIGS. 1 and 2A to 2G , at least the entire outer surface 12 of the upper hemisphere 3 is red, orangey-red, orange in colour, or of any other colour in the range of bright colours between red and orange, which has the advantage of contrasting with the ground sufficiently to allow identification for birds, in particular hunting raptors during their extremely fast diving movements, or for identification from a glider or an aircraft. This colour also has the advantage of being visible during hazy weather or during fog. It will be understood that any other portion of the signalling device 1 could be of this colour or another colour, provided that the constraint of contrast with the ground and the visibility in fog or during hazy weather is complied with. According to a variant of an embodiment of the invention, the device 1 may comprise at least two colours. In an illustrative example, if the upper hemisphere 3 of the device 1 is orange, the lower hemisphere 4 could be green or yellow. A device 1 which is in at least two colours also allows identification in the event of winds which are blowing at high speeds and bringing about movements of the transmission lines. According to another variant, the coating of the device 1 could be partially photoluminescent. In that manner, in an illustrative example of an embodiment of the invention, the lower hemisphere 4 is green or yellow and photoluminescent, which, combined with the orange upper hemisphere 3 , allows visibility at any time, including at night, without using an additional energy source. The spherical shape of the device 1 of the illustrative example of FIGS. 1 and 2A to 2G prevents the accumulation of snow on the outer surfaces 12 , 13 . According to a variant of an embodiment of the invention, this may be complemented by an ice-repellent coating in order to prevent as effectively as possible any deposit of snow and/or ice which would reduce the visibility of the device 1 to birds. Various ice-repellent treatments exist on the market and can be used to prevent the formation of ice and/or piles of snow on a signalling device, high-performance nanotechnologies, latex-based coatings, silicone-based coatings or coatings based on polytetrafluoroethylene or PTFE. In the illustrative example of FIG. 1 and FIGS. 2A to 2G , the device 1 could have been processed with a PTFE coating which, in addition to the ice-repellent characteristics, also has the advantage of conserving the appearance of the surface to which it is applied and may reduce the adhesion of ice to the application surface by up to 80%. One advantage is that the weight of the device 1 can be limited in an icy environment, which prevents an excessive weight from being placed on the cable 2 of the transmission line. Such a coating allows the quality of the signalling colours to be conserved, for example, the orange colour of the upper hemisphere 3 , and the photoluminescent yellow or green colour of the lower signalling element 4 . Ice-repellent coatings also have hydrophobic properties which allows the surface 12 , 13 of the device 1 to be kept clean during wet weather, given that water does not adhere thereto. The visibility of the device 1 can therefore be ensured in a durable manner because the device 1 is thereby protected from changes in colour and deposits of dust which could make it less visible to pilots or birds. FIG. 3 is a diagram illustrating in a simplified manner an application of the assembly of a signalling device 1 as described in the illustrative examples of an embodiment of the invention with reference to FIGS. 1 and 2A to 2G on cables 2 , 2 ′, 2 ″ between two successive pylons 47 , 48 of a high-voltage line. The configuration described with reference to FIG. 3 is therefore purely illustrative and must not therefore be interpreted as being the only possible configuration or the only possible application of an embodiment of the invention. The signalling devices 1 used for the illustrative example of FIG. 3 have the advantages described above with reference to the illustrative examples of embodiments described with reference to FIGS. 1 and 2A to 2G . In the illustrative example of FIG. 3 , the two pylons 47 , 48 are spaced apart by approximately 120 m but this distance may vary in reality, for example, in accordance with the geography of the location where the transmission lines are installed. FIG. 3 further illustrates that the two pylons 47 , 48 support three conductive cables 2 , 2 ′, 2 ″ of an aerial transmission line but the invention may be applied to transmission lines whose pylons support more or fewer cables than the configuration illustrated in FIG. 3 . In the example of FIG. 3 , the two outermost conductive cables 2 , 2 ″ supported by the pylons 47 , 48 are each provided with five signalling devices 1 according to the invention. Projecting from the point of view of the bird 49 which is approaching, the ten devices 1 are spaced apart from each other by approximately 11 m. In other configurations, a single cable 2 or all the cables 2 , 2 ′, 2 ″ could be provided with signalling devices 1 . In still other configurations, each cable 2 , 2 ′, 2 ″ could receive more than five devices 1 , for example, ten devices 1 spaced apart by 11 m over the entire length of the same cable 2 , 2 ′, 2 ″ between the two pylons 47 , 48 . All the numerical configurations of the devices 1 on one or more cables 2 , 2 ′, 2 ″ are permitted provided that the total weight supported does not weaken the structure of the aerial transmission line, in particular does not apply excessive tension to the cables. In the example of FIG. 3 , the device 1 is therefore of substantially spherical shape with a diameter of approximately 250 mm and is composed of two hollow aluminium hemispheres 3 , 4 . The total weight of a signalling device 1 is thus maintained at approximately 500 g, which allows at least approximately ten of them to be installed between two pylons 47 , 48 , with spacings of only 11 m between each device 1 if the two pylons are spaced apart by approximately 120 m. In the case illustrated in FIG. 3 , the projected surface-area per unit is approximately 49090 mm 2 for a total exposed surface-area of 0.49 m 2 if ten devices 1 are mounted on the conductive cables 2 , 2 ′, 2 ″. Those values are not restrictive and depend on the geometry of the signalling device 1 and the configuration selected for the assembly of the devices 1 on the cables 2 , 2 ′, 2 ″. In the case of pylons 47 , 48 which are spaced apart by approximately 120 m, the use of devices 1 according to the invention allows more devices 1 to be mounted and thereby an increase by a factor of 4 in the total exposed surface-area which is therefore visible to birds in relation to the devices known in the prior art, such as the helical system for a total combined weight which is less. Therefore, the signalling device 1 of a transmission line, in particular a high-voltage or very-high-voltage aerial line, according to the invention, and the different possible variants and embodiments thereof has at least the same advantages as some devices known in the prior art, that is to say, ease of installation and speed of installation, and dispenses with the use of tools, which therefore allows the devices to be used in the case of assembly carried out by an operator being suspended from a helicopter. The invention and its various variants further have a number of advantages and/or improvements in relation to the prior art: geometry preventing deposits of snow and/or ice, in particular in the case of a spherical shape, optionally complemented by an ice-repellent coating; more effective signalling owing to a total visible projected surface-area which is increased over the prior art, in particular in terms of the spherical geometry which allows effective signalling in all angular directions; effective signalling during the day including in foggy weather by means of visible colours which contrast with the relief of the landscape, in particular the colour orange, in particular for the upper signalling element; night-time signalling which is independent of a source of energy in the case of photoluminescent materials or coatings, in particular the use of the photoluminescent colour green and/or yellow for the lower signalling element; improvement in the visibility at high wind speeds in the case of a signalling element which has at least two colours; weight limited to approximately 500 g including in the case of an element which uses conductive materials such as aluminium, allowing the installation of a plurality of signalling devices on a line between two successive pylons for a limited total weight and therefore a controlled and limited tension of the cables; possible use whatever the type of transmission line, whether low-voltage, medium-voltage, high-voltage, very-high-voltage or ultra-high-voltage owing to the conductive properties of the device, and therefore the possibility of installation on lines whose temperatures may reach 250° C. or more; service-life and visibility which are increased over the prior art, in particular in the case of use of an ice-repellent coating; system clamping the cable inside the signalling device, preventing slippage of the device on the cable; control of the clamping torque, in particular when using a clamping element comprising a meltable screw head. It should be noted that the various embodiments and features of the different illustrative examples of embodiments of the invention may all be combined in order to construct additional advantageous embodiments of the present invention. LIST OF REFERENCE NUMERALS  1 Line signalling device  2 Transmission line cable  3 Upper hemisphere/signalling element  4 Lower hemisphere/signalling element  5 Clamping means  6 First parallel bar  7 Second parallel bar  8 Lower clamping element  9 Lower clamping flange 10 Upper clamping element 11 Upper clamping flange 12 Outer surface of 3 13 Outer surface of 4 14 First hole of 3 14′ Second hole of 3 15 First hole of 4 16 Second hole of 4 17 Edge of hemisphere 3 18 Edge of hemisphere 4 19 Lug of 8 20 First lug having oblong hole of 8 21 Second lug having oblong hole of 8 22 First lug of 10 23 Second lug of 10 24 Abutment surface of screw 26 25 Hook of 10 26 Screw having hexagonal head 27 Meltable head for hexagonal screw 28 Hexagonal ring 29 First fin 30 Second fin 31 Meltable ring 32 Hole for clip-fit projection 33 Hole for clip-fit projection 34 First clip-fit hole 34′ Second clip-fit hole 35 Stop ring 36 Stop ring 37 Stop ring 38 Stop ring 39 Stop ring 40 First flexible clip-fit plate 41 Recess for stop ring 42 Recess for stop ring 43 Second flexible clip-fit plate 44 Clip-fit projection 44′ Clip-fit projection 45 Recess for stop ring 46 Recess for stop ring 47 Pylon 48 Pylon 49 Flying bird 50 Clamping block

The invention relates to a signalling device ( 1 ) for an aerial transmission line ( 2 ) comprising two signalling elements ( 3, 4 ) which are configured to be mounted one against the other around a conductor portion ( 2 ) of the transmission line, in which at least one of the two signalling elements ( 3, 4 ) comprises at least partially an outer signalling coating in the context of air safety, which device is characterized in that the two signalling elements ( 3, 4 ) are at least partially electrically conductive and at least one of the two signalling elements ( 3, 4 ) comprises a clamping means ( 5 ) which is configured to clamp the conductor portion ( 2 ) of the transmission line. The invention also relates to a method for assembling such a device on a high-voltage aerial transmission line.

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a U.S. National Stage Application of International Application No. PCT/EP2009/056225 filed May 22, 2009, which designates the United States of America, and claims priority to EP Application No. 08011205.5 filed Jun. 19, 2008. The contents of which are hereby incorporated by reference in their entirety. TECHNICAL FIELD [0002] The present invention relates to an operating method for a continuous rolling train which has a number of roll stands, with a rolling stock passing through the continuous rolling train being rolled in a plurality of the roll stands in succession, such that the rolling stock has predetermined final properties when it leaves the rolling train. [0003] The present invention also relates to a computer program which has machine code which can be executed directly by a control device of a continuous rolling train and the execution of which by the control device has the effect that the control device operates the continuous rolling train according to such an operating method. [0004] The present invention also relates to a data carrier on which such a computer program is stored in machine-readable form. [0005] The present invention also relates to a control device of a continuous rolling train, which control device is programmed with a computer program such that the control device operates the continuous rolling train according to an operating method of the type explained above. [0006] Finally, the present invention relates to a continuous rolling train having a number of roll stands and having a control device of the above-described type, with the roll stands being controlled by the control device. BACKGROUND [0007] An operating method of the type mentioned at the beginning is known for example from US 2008/060403 A1. Said document explains a way in which the continuous operation of the continuous rolling train can be maintained despite the fact that the rolling stock passing through the continuous rolling train has a critical transition region which cannot be rolled safely. In essence, the teaching of US 2008/060403 A1 concerns tracking the path of the transition region through the continuous rolling train and lifting each of the roll stands of the continuous rolling train when the critical transition region reaches the respective roll stand and screwing down the respective roll stand on the rolling stock again and continuing the rolling process when the critical transition region has passed the respective roll stand. The rolling stock is thus rolled in the roll stands of the continuous rolling train only outside the critical transition region. The critical transition region itself and parts of the rolling stock adjoining the critical transition region pass through the entire continuous rolling train without being rolled. [0008] In continuous rolling trains, rolling stock should be rolled with as little interruption as possible (that is, continuously). Therefore, at the entry side of the continuous rolling train, individual coils are brought together and connected to one another—generally by means of welding. This approach is taken in particular for the cold rolling of sheet metal, that is to say a strip-shaped rolling stock. [0009] The rolling of the rolling stock causes the rolls of the roll stands to wear. Here, within one of the roll stands, the most intense wear occurs in the working rolls of the respective roll stand. Support rolls and—if present—intermediate rolls wear only to a lesser extent. In terms of the continuous rolling train as a whole, the wear increases toward the exit side of the continuous rolling train. [0010] In the prior art, to exchange rolls of a roll stand, it is known to bring the continuous rolling train to a stop, wherein the rolling stock remains in the continuous rolling train, that is to say is merely brought to a halt. As a result of the stoppage, rolling defects are generated at the stoppage points of the rolling stock. The rolling defects may comprise in particular dimensional defects and surface defects. If relatively high demands are placed on the quality of the rolling stock, that part of the rolling stock in which the rolling defects occur must be scrapped. Here, that part of the rolling stock which is to be scrapped may have a considerable length, for example 50 to 100 m. Furthermore, operational efficiency is reduced on account of the temporary stoppage of the continuous rolling train. SUMMARY [0011] It would be possible both to eliminate the rolling defects and also increase operational efficiency if it were possible for a roll stand of the continuous rolling train to be removed from and integrated into the continuous rolling train in a jolt-free manner during ongoing operation of the continuous rolling train. Hence, according to various embodiments, such possibilities can be provided. [0012] According to an embodiment, in an operating method for a continuous rolling train which has a number of roll stands, with a rolling stock passing through the continuous rolling train being rolled in a plurality of the roll stands in succession, such that the rolling stock has predetermined final properties when it leaves the rolling train, to remove one of the roll stands rolling the rolling stock from the continuous rolling train during the rolling of the rolling stock, the method comprises: a control device of the continuous rolling train controls the roll stand to be removed such that the roll stand to be removed is completely relieved of load according to a defined temporal load relief profile, such that the roll stand to be removed rolls a certain section of the rolling stock during the load relief profile, the control device controls at least one other of the roll stands of the continuous rolling train such that the at least one other roll stand has load applied to it according to a defined temporal load application profile, wherein the load relief profile of the roll stand to be removed and the load application profile of the at least one other roll stand are coordinated with one another such that, during the load application profile, the at least one other roll stand rolls one and the same section of the rolling stock as the roll stand to be removed during the load relief profile, and such that the final properties of the rolling stock are maintained, —the control device controls a rotational speed of working rolls of the roll stand to be removed until the latter is completely relieved of load, in such a way that an exit speed of the rolling stock effected by the rolling of the rolling stock in the roll stand to be removed corresponds at all times to a predetermined setpoint exit speed, the control device controls the roll stand to be removed, after the latter has been completely relieved of load, and so as to maintain a correspondence of the rotational speed of the working rolls with the setpoint exit speed, such that the working rolls of the roll stand to be removed are lifted off the rolling stock, and said control device then brings the roll stand to be removed to a stop. [0016] According to a further embodiment, to compensate the relief of load of the roll stand to be removed, the control device may apply load to a single other roll stand. According to a further embodiment, to compensate the relief of load of the roll stand to be removed, the control device may integrate the at least one other roll stand into the continuous rolling train. According to a further embodiment, to relieve the roll stand to be removed of load, the control device may control a rolling gap of the roll stand to be removed by correspondingly predefining a speed relationship relative to a roll stand, which is positioned upstream of the roll stand to be removed and is likewise rolling the rolling stock, of the continuous rolling train in conjunction with tension regulation, which acts on the screw-down of the roll stand to be removed, for a section of the rolling stock running into the roll stand to be removed. According to a further embodiment, to relieve the roll stand to be removed of load, the control device may control a rolling gap of the roll stand to be removed by position regulation or force regulation. According to a further embodiment, during the relief of load of the roll stand to be removed, the control device may regulate a tension prevailing in a section of the rolling stock running into the roll stand to be removed by adjusting the rotational speed of the working rolls of the roll stand to be removed, and—the control device may take the adjustment of the rotational speed of the working rolls of the roll stand to be removed into consideration in at least one roll stand, which is positioned downstream of the roll stand to be removed and is likewise rolling the rolling stock, of the continuous rolling train. According to a further embodiment, during the relief of load of the roll stand to be removed, the control device may regulate a tension prevailing in a section of the rolling stock running into the roll stand to be removed by adjusting the rotational speed of working rolls of a roll stand, which is positioned directly upstream of the roll stand to be removed and is likewise rolling the rolling stock, of the continuous rolling train and—the control device may take the adjustment of the rotational speed of the working rolls of the roll stand, which is positioned directly upstream of the roll stand to be removed and is likewise rolling the rolling stock, into consideration in at least one roll stand, which is positioned indirectly upstream of the roll stand to be removed and is likewise rolling the rolling stock, of the continuous rolling train. [0017] According to another embodiment, in an operating method for a continuous rolling train which has a number of roll stands, with a rolling stock passing through the continuous rolling train being rolled in a plurality of the roll stands in succession, such that the rolling stock has predetermined final properties when it leaves the rolling train, in particular an operating method as described above, to integrate a roll stand which is not rolling the rolling stock into the continuous rolling train during the rolling of the rolling stock, the method may comprise: a control device of the continuous rolling train controls the roll stand to be integrated such that a rotational speed of working rolls of the roll stand to be integrated corresponds to a setpoint exit speed of the rolling stock at the location of the roll stand to be integrated, and then controls the roll stand to be integrated such that the working rolls are screwed down on the rolling stock but the rolling stock is not yet rolled in the roll stand to be integrated, after the screw-down of the working rolls of the roll stand to be integrated on the rolling stock, the control device controls the roll stand to be integrated such that the roll stand to be integrated has load applied to it according to a defined temporal load application profile, such that the roll stand to be integrated rolls a certain section of the rolling stock during the load application profile, the control device controls at least one other of the roll stands of the continuous rolling train such that the at least one other roll stand is relieved of load according to a defined temporal load relief profile, wherein the load application profile of the roll stand to be integrated and the load relief profile of the at least one other roll stand are coordinated with one another such that, during the load relief profile, the at least one other roll stand rolls one and the same section of the rolling stock as the roll stand to be integrated during the load application profile, and such that the final properties of the rolling stock are maintained, after the application of load, the control device controls the rotational speed of the working rolls of the roll stand to be integrated such that an exit speed, effected by the rolling of the rolling stock in the roll stand to be integrated, of the rolling stock at the location of the roll stand to be integrated corresponds at all times to the setpoint exit speed. [0022] According to a further embodiment of the above method, to compensate the application of load to the roll stand to be integrated, the control device may relieve a single other roll stand of load. According to a further embodiment of the above method, to compensate the application of load to the roll stand to be integrated, the control device may remove the at least one other roll stand from the continuous rolling train. According to a further embodiment of the above method, to apply load to the roll stand to be integrated, the control device may control a rolling gap of the roll stand to be integrated by correspondingly predefining a speed relationship relative to a roll stand, which is positioned upstream of the roll stand to be integrated and is rolling the rolling stock, of the continuous rolling train in conjunction with tension regulation, which acts on the screw-down of the roll stand to be integrated, for a section of the rolling stock running into the roll stand to be integrated. According to a further embodiment of the above method, to apply load to the roll stand to be integrated, the control device may control a rolling gap of the roll stand to be integrated by position regulation or force regulation. According to a further embodiment of the above method, during the application of load to the roll stand to be integrated, the control device may regulate a tension prevailing in a section of the rolling stock running into the roll stand to be integrated by adjusting the rotational speed of the working rolls of the roll stand to be integrated, and the control device may take the adjustment of the rotational speed of the working rolls of the roll stand to be integrated into consideration in at least one roll stand, which is positioned downstream of the roll stand to be integrated and is rolling the rolling stock, of the continuous rolling train. According to a further embodiment of the above method, during the application of load to the roll stand to be integrated, the control device may regulate a tension prevailing in a section of the rolling stock running into the roll stand to be integrated by adjusting a rotational speed of working rolls of a roll stand, which is positioned directly upstream of the roll stand to be integrated and is rolling the rolling stock, of the continuous rolling train, and the control device may take the adjustment of the rotational speed of the working rolls of the roll stand, which is positioned directly upstream of the roll stand to be integrated and is rolling the rolling stock, into consideration in at least one roll stand, which is positioned indirectly upstream of the roll stand to be integrated and is likewise rolling the rolling stock, of the continuous rolling train. [0023] According to another embodiment, a computer program may have machine code which can be executed directly by a control device of a continuous rolling train and the execution of which by the control device has the effect that the control device operates the continuous rolling train according to an operating method as described above. [0024] According to another embodiment, a data carrier may store a computer program as described above in machine-readable form. [0025] According to another embodiment, a control device of a continuous rolling train, may be programmed with a computer program as described above such that the control device operates the continuous rolling train according to any of the operating methods as described above. [0026] According to yet another embodiment, a continuous rolling train may have a number of roll stands and having a control device as described above, with the roll stands being controlled by the control device. BRIEF DESCRIPTION OF THE DRAWINGS [0027] Further advantages and details will emerge from the following description of exemplary embodiments in conjunction with the drawings, in which, in each case in the form of a diagrammatic illustration: [0028] FIG. 1 schematically shows a continuous rolling train, [0029] FIGS. 2 to 6 show flow diagrams, [0030] FIGS. 7 to 9 show possible load relief profiles and load application profiles, and [0031] FIGS. 10 to 12 show possible embodiments of a section of the continuous rolling train from FIG. 1 . DETAILED DESCRIPTION [0032] As regards the jolt-free removal of one of the roll stands, which is rolling the rolling stock, from the continuous rolling train, it is provided according to various embodiments that, during the rolling of the rolling stock, the following measures are taken: a control device of the continuous rolling train controls the roll stand to be removed such that the roll stand to be removed is completely relieved of load according to a defined temporal load relief profile, such that the roll stand to be removed rolls a certain section of the rolling stock during the load relief profile, the control device controls at least one other of the roll stands of the continuous rolling train such that the at least one other roll stand has load applied to it according to a defined temporal load application profile, wherein the load relief profile of the roll stand to be removed and the load application profile of the at least one other roll stand are coordinated with one another such that, during the load application profile, the at least one other roll stand rolls one and the same section of the rolling stock as the roll stand to be removed during the load relief profile, and such that the final properties of the rolling stock are maintained, the control device controls a rotational speed of working rolls of the roll stand to be removed until the latter is completely relieved of load, in such a way that an exit speed of the rolling stock effected by the rolling of the rolling stock in the roll stand to be removed corresponds at all times to a predetermined setpoint exit speed, the control device controls the roll stand to be removed, after the latter has been completely relieved of load, and so as to maintain a correspondence of the rotational speed of the working rolls with the setpoint exit speed, such that the working rolls of the roll stand to be removed are lifted off the rolling stock, and said control device then brings the roll stand to be removed to a stop. [0037] The fact that the roll stand to be removed rolls a certain section of the rolling stock during the load relief profile and the at least one other roll stand is controlled such that another roll stand rolls one and the same section of the rolling stock during the load application profile is also referred to hereinafter as “local simultaneity”. Local simultaneity can be achieved directly by path tracking. Here, experts are generally familiar with path tracking. [0038] Within the context of various embodiments, it is possible for the at least one other roll stand to be positioned upstream of the roll stand to be removed. It is however likewise possible for the at least one other roll stand to be positioned downstream of the roll stand to be removed. [0039] In one embodiment, it is provided that, to compensate the relief of load of the roll stand to be removed, the control device applies load to a single other roll stand. [0040] Here, this characteristic is meant not in the sense that no changes may occur in the other roll stands, but rather in the sense that the reduction in pass reduction arising as a result of the relief of load of the roll stand to be removed is compensated by a corresponding increase in pass reduction in a single other roll stand. [0041] In one embodiment, it is provided that, to compensate the relief of load of the roll stand to be removed, the control device integrates the at least one other roll stand into the continuous rolling train. In this case, a roll stand exchange thus takes place. [0042] To relieve the roll stand to be removed of load, it is possible for the control device to control a rolling gap of the roll stand to be removed by correspondingly predefining a speed relationship relative to a roll stand, which is positioned upstream of the roll stand to be removed and is likewise rolling the rolling stock, of the continuous rolling train in conjunction with tension regulation, which acts on the screw-down of the roll stand to be removed, for a section of the rolling stock running into the roll stand to be removed. [0043] To relieve the roll stand to be removed of load, it is alternatively possible for the control device to control a rolling gap of the roll stand to be removed by position regulation or force regulation. [0044] If the control device carries out position regulation or force regulation to relieve the roll stand to be removed of load, it is possible, during the relief of load of the roll stand to be removed, for the control device to regulate a tension prevailing in a section of the rolling stock running into the roll stand to be removed by adjusting the rotational speed of the working rolls of the roll stand to be removed. In this case, the control device preferably takes the adjustment of the rotational speed of the working rolls of the roll stand to be removed into consideration in at least one roll stand, which is positioned downstream of the roll stand to be removed and is likewise rolling the rolling stock, of the continuous rolling train. [0045] It is alternatively possible, during the relief of load of the roll stand to be removed, for the control device to regulate a tension prevailing in a section of the rolling stock running into the roll stand to be removed by adjusting the rotational speed of working rolls of a roll stand, which is positioned directly upstream of the roll stand to be removed and is likewise rolling the rolling stock, of the continuous rolling train. In this case, the control device preferably takes the adjustment of the rotational speed of the working rolls of the roll stand, which is positioned directly upstream of the roll stand to be removed and is likewise rolling the rolling stock, into consideration in at least one roll stand, which is positioned indirectly upstream of the roll stand to be removed and is likewise rolling the rolling stock, of the continuous rolling train. [0046] The jolt-free integration of a roll stand takes place substantially inversely to the jolt-free removal of a roll stand. As regards the jolt-free integration of a roll stand which is not rolling the rolling stock into the continuous rolling train during the rolling of the rolling stock, it is therefore provided according to various embodiments that, during the rolling of the rolling stock, the following measures are taken: a control device of the continuous rolling train controls the roll stand to be integrated such that a rotational speed of working rolls of the roll stand to be integrated corresponds to a setpoint exit speed of the rolling stock at the location of the roll stand to be integrated, and then controls the roll stand to be integrated such that the working rolls are screwed down on the rolling stock but the rolling stock is not yet rolled in the roll stand to be integrated, after the screw-down of the working rolls of the roll stand to be integrated on the rolling stock, the control device controls the roll stand to be integrated such that the roll stand to be integrated has load applied to it according to a defined temporal load application profile, such that the roll stand to be integrated rolls a certain section of the rolling stock during the load application profile, the control device controls at least one other of the roll stands of the continuous rolling train such that the at least one other roll stand is relieved of load according to a defined temporal load relief profile, wherein the load application profile of the roll stand to be integrated and the load relief profile of the at least one other roll stand are coordinated with one another such that, during the load relief profile, the at least one other roll stand rolls one and the same section of the rolling stock as the roll stand to be integrated during the load application profile, and such that the final properties of the rolling stock are maintained, after the application of load, the control device controls the rotational speed of the working rolls of the roll stand to be integrated such that an exit speed, effected by the rolling of the rolling stock in the roll stand to be integrated, of the rolling stock at the location of the roll stand to be integrated corresponds at all times to the setpoint exit speed. [0051] The term “local simultaneity” is used here too. Here, the term “local simultaneity” is to be understood in the same sense as in the case of the removal of a roll stand from the continuous rolling train. Similarly to the removal of a roll stand, it is also possible during the integration of a roll stand that the at least one other roll stand is positioned upstream of the roll stand to be integrated. It is however likewise possible for the at least one other roll stand to be positioned downstream of the roll stand to be integrated. [0052] In an embodiment, it is provided that, to compensate the application of load to the roll stand to be integrated, the control device relieves a single other roll stand of load. Similarly to the relief of load of a roll stand to be removed, the statement is to be understood here to mean that the pass reduction occurring as a result of the application of load to the roll stand to be integrated leads to a corresponding reduction in pass reduction of a single other roll stand which is relieved of load. [0053] To compensate the application of load to the roll stand to be integrated, it is particularly preferable for the control device to remove the at least one other roll stand from the continuous rolling train. [0054] Similarly to the removal of a roll stand, it is also possible during the integration of a roll stand that, to apply load to the roll stand to be integrated, the control device may control a rolling gap of the roll stand to be integrated by correspondingly predefining a speed relationship relative to a roll stand, which is positioned upstream of the roll stand to be integrated and is rolling the rolling stock, of the continuous rolling train in conjunction with tension regulation, which acts on the screw-down of the roll stand to be integrated, for a section of the rolling stock running into the roll stand to be integrated. It is likewise alternatively possible, to apply load to the roll stand to be integrated, for the control device to control a rolling gap of the roll stand to be integrated by position regulation or force regulation. [0055] Similarly to the removal of a roll stand, in the case of position regulation or force regulation, it is possible, during the application of load to the roll stand to be integrated, for the control device to regulate a tension prevailing in a section of the rolling stock running into the roll stand to be integrated by adjusting the rotational speed of the working rolls of the roll stand to be integrated. In this case, the control device preferably takes the adjustment of the rotational speed of the working rolls of the roll stand to be integrated into consideration in at least one roll stand, which is positioned downstream of the roll stand to be integrated and is rolling the rolling stock, of the continuous rolling train. [0056] It is alternatively possible, during the application of load to the roll stand to be integrated, for the control device to regulate a tension prevailing in a section of the rolling stock running into the roll stand to be integrated by adjusting a rotational speed of working rolls of a roll stand, which is positioned directly upstream of the roll stand to be integrated and is rolling the rolling stock, of the continuous rolling train. In this case, the control device preferably takes the adjustment of the rotational speed of the working rolls of the roll stand, which is positioned directly upstream of the roll stand to be integrated and is rolling the rolling stock, into consideration in at least one roll stand, which is positioned indirectly upstream of the roll stand to be integrated and is likewise rolling the rolling stock, of the continuous rolling train. [0057] The computer program according to various embodiments has machine code, the execution of which by the control device has the effect that the control device operates the continuous rolling train according to an operating method as described above. A computer program of said type is stored in machine-readable form on the data carrier. The control device of the continuous rolling train is programmed with a computer program according to various embodiments. The continuous rolling train has a control device of said type. [0058] According to FIG. 1 , a continuous rolling train has a number of roll stands 1 , 1 ′, 1 ″. Illustrated here are only working rolls 3 , 3 ′, 3 ″ of the roll stands 1 , 1 ′, 1 ″. The roll stands 1 , 1 ′, 1 ″ may however have further rolls, for example support rolls and intermediate rolls. A rolling stock 2 passes through the continuous rolling train. The rolling stock 2 is generally of strip-shaped form, for example a metal sheet. In principle, the rolling stock 2 could however have a different cross-sectional shape. [0059] As it passes through the continuous rolling train, the rolling stock 2 is rolled in a plurality of the roll stands 1 , 1 ′, 1 ″ of the continuous rolling train in succession. Here, cold rolling of the rolling stock 2 generally takes place. Hot rolling of the rolling stock 2 is however also possible in principle. On account of the rolling of the rolling stock 2 , the rolling stock 2 has predetermined final properties when it leaves the continuous rolling train, for example predetermined final dimensions and a predetermined surface texture (in particular surface roughness). Here, the final properties of the rolling stock 2 differ from the starting properties of the rolling stock 2 . The starting properties of the rolling stock 2 are the properties the rolling stock 2 has upon entering the continuous rolling train. [0060] It is possible for the rolling stock 2 to be rolled in all the roll stands 1 , 1 ′, 1 ″ of the continuous rolling train. In FIG. 1 , however, the roll stand 1 ′ is not in engagement. The working rolls 3 ′ of said roll stand 1 ′ are thus spaced apart from the rolling stock 2 . It will hereinafter be described inter alia how the roll stand 1 ′ can be integrated into the continuous rolling train in a jolt-free manner during ongoing operation of the continuous rolling train (that is to say while the rolling stock 2 is being rolled in the continuous rolling train). It will likewise be described how the roll stand 1 ″ which is in engagement in FIG. 1 can be removed from the continuous rolling train in a jolt-free manner during ongoing operation of the continuous rolling train. [0061] In FIG. 1 , the roll stand 1 ′ to be integrated is the second of six roll stands 1 , 1 ′, 1 ″ of the cold-rolling train. The roll stand 1 ″ to be removed is the fifth of the roll stands 1 , 1 ′, 1 ″ of the continuous rolling train. This illustration is however purely an example. It is possible for both the roll stand 1 ′ to be integrated and also the roll stand 1 ″ to be removed to be any one of the roll stands 1 , 1 ′, 1 ″ of the continuous rolling train, that is to say the first, second, third etc. roll stand 1 , 1 ′, 1 ″ of the continuous rolling train. Also, the roll stand 1 ′ to be integrated may alternatively be arranged upstream or downstream of the roll stand 1 ″ to be removed as viewed in the running direction x of the rolling stock 2 . Finally, instead of six roll stands, the continuous rolling train may also have more or fewer roll stands 1 , 1 ′, 1 ″. [0062] The continuous rolling train has a control device 4 which controls the roll stands 1 , 1 ′, 1 ″. The control device 4 thus defines how the continuous rolling train is operated. For this purpose, the control device 4 generally executes a computer program 5 with which the control device 4 is programmed. [0063] According to FIG. 1 , the computer program 5 has machine code 6 which can be directly executed by the control device 4 . The execution of the machine code 6 by the control device 4 has the effect that the control device 4 operates the continuous rolling train according to operating processes which will be explained in more detail below in conjunction with further figures. [0064] The computer program 5 may be supplied to the control device 4 in various ways. For example, it is possible for the computer program 5 to be supplied to the control device 4 via a computer-computer connection 7 . The computer-computer connection 7 may for example be the World Wide Web or a local computer network (LAN). Alternatively, the computer program 5 may be supplied to the control device 4 by means of a data carrier 8 on which the computer program 5 is stored in machine-readable—usually digital—form. Purely by way of example, a CD-ROM is schematically illustrated as a data carrier 8 in FIG. 1 . The data carrier 8 could however also be of some other form, for example a USB memory stick or SD memory card. [0065] During operation, the control device 4 controls the continuous rolling train according to an operating method which will be explained below in conjunction with FIG. 2 . [0066] According to FIG. 2 , in a step S 1 , the control device 4 checks whether one of the roll stands 1 , 1 ′, 1 ″ should be removed. For example, the control device 4 may for this purpose receive a corresponding input from an operator 9 . [0067] Similarly, in steps S 3 and S 4 , the control device 4 checks whether one of the roll stands 1 , 1 ′, 1 ″ should be integrated into the continuous rolling train. If this is the case, in steps S 5 and S 6 , the control device 4 defines which of the roll stands 1 , 1 ′, 1 ″ should be integrated. Here, too, a corresponding input from the operator 9 is possible. [0068] Depending on the result of the checks in steps S 1 , S 3 and S 4 , one of the steps S 7 to S 10 is then carried out. In step S 7 , a roll stand exchange takes place, that is to say the integration of the roll stand 1 ′ to be integrated and the locally simultaneous (for definition, see above) removal of the roll stand 1 ″ to be removed. The removal of the roll stand 1 ″ to be removed takes place in step S 8 . The integration of the roll stand 1 ′ to be integrated takes place in step S 9 . In step S 10 , normal rolling operation such as is generally known for continuous rolling trains takes place. [0069] Instead of the method of FIG. 2 , it is possible for a simplified method to be carried out, which will be explained below in conjunction with FIG. 3 . The basic difference between the approaches of FIG. 2 and FIG. 3 is that, in the approach of FIG. 3 , in contrast to the approach of FIG. 2 , the isolated integration of a roll stand 1 ′ to be integrated and the isolated removal of a roll stand 1 ″ to be removed are not permitted, but rather a roll stand exchange always takes place. The approach of FIG. 3 therefore contains only the steps S 1 , S 2 , S 5 , S 7 and S 10 of FIG. 2 . [0070] During the course of step S 8 , that is to say to remove the roll stand 1 ″ to be removed without the simultaneous integration of another roll stand 1 ′, the following steps are taken, according to FIG. 4 : [0071] In a step S 11 , the control device 4 begins to relieve the roll stand 1 ″ to be removed of load. In step S 11 , the control device 4 begins to locally simultaneously apply load to at least one other roll stand 1 , 1 ′. If, at the time of execution of step S 11 , the roll stand 1 ′ is not loaded, it is (theoretically) possible here for the roll stand 1 ′ which is initially not yet loaded to concomitantly have load applied to it. Generally, however, only the other roll stands 1 which are already in engagement and rolling the rolling stock 2 are loaded. [0072] In a step S 12 , the control device 4 continues the relief of load of the roll stand 1 ″ to be removed according to a defined temporal load relief profile. Here, the control device 4 controls a rotational speed vU″ of the working rolls 3 ″ of the roll stand 1 ″ to be removed such that an exit speed v″ of the rolling stock 2 effected by the rolling of the rolling stock 2 in the roll stand 1 ″ to be removed corresponds at all times to a predetermined setpoint exit speed v″*. Here, the setpoint exit speed v″* may alternatively be temporally constant or temporally variable. During the determination of the required rotational speed vU″, the control device 4 takes into consideration in particular the change in forward slip arising in the roll stand 1 ″ to be removed as a result of the relief of load of the roll stand 1 ″ to be removed. The corresponding approach is known per se, for example from US 2008/060403 A1 as cited above. [0073] In a step S 13 , the control device 4 locally simultaneously continues the application of load to the at least one other roll stand 1 , 1 ′ according to a defined temporal load application profile. Here, too, the rotational speeds vU, vU′ of the working rolls 3 , 3 ′ of the corresponding roll stands 1 , 1 ′ are always determined corresponding to the changing forward slip in the respective roll stand 1 , 1 ′, such that respective local exit speeds v, v′ correspond to a respective setpoint exit speed v*, v′*. [0074] The load application profiles of the other roll stands 1 , 1 ′ are coordinated with the load relief profile of the roll stand 1 ″ to be removed such that the final properties of the rolling stock 2 are maintained. The relief of load of the roll stand to be removed and the application of load to the other roll stands 1 , 1 ′ therefore has no effect on the quality of the rolling stock 2 produced. [0075] In a step S 14 , the control device 4 checks whether the relief of load of the roll stand 1 ″ to be removed is already complete. If this is not the case, the control device 4 returns to step S 12 , and thus continues the relief of load of the roll stand 1 ″ to be removed and the corresponding application of load to the at least one other roll stand 1 , 1 ′. [0076] When the relief of load of the roll stand 1 ″ to be removed is complete, the control device 4 passes to a step S 15 . In step S 15 , the control device 4 controls the roll stand 1 ″ to be removed such that the correspondence of the rotational speed vU″ of the working rolls 3 ″ of the roll stand 1 ″ to be removed with the setpoint exit speed v″* is maintained. The control device 4 then controls the roll stand 1 ″ to be removed such that the working rolls 3 ″ of the roll stand 1 ″ to be removed are lifted off the rolling stock 2 . After the working rolls 3 ″ of the roll stand 1 ″ to be removed are lifted off, the control device 4 brings the roll stand 1 ″ to be removed to a stop in a step S 17 . [0077] At the end of the relief of load of the roll stand 1 ′ to be removed, tensions ZA, ZB prevailing in the rolling stock 2 directly upstream and directly downstream of the roll stand 1 ″ to be removed must be equal. This is because the rolling stock 2 would otherwise slip along the working rolls 3 ″ of the roll stand 1 ″ to be removed. The tensions ZA, ZB upstream and downstream of the roll stand 1 ″ to be removed must therefore be matched to one another. The matching may alternatively take place at the start of step S 11 , between steps S 11 and S 12 or during the course of step S 12 . The corresponding approach is known in principle from US 2008/060403 A1, as already cited above. [0078] In the approach of FIG. 4 , the additional load application which occurs is generally distributed over a plurality of other roll stands 1 . In individual cases, however, it is possible for the control device 4 to apply load to only a single other roll stand 1 during the execution of the method of FIG. 4 . [0079] To integrate a roll stand 1 ′ to be integrated without locally simultaneous removal of another roll stand 1 ″, that is to say to implement the step S 9 of FIG. 2 , the following approach is taken, according to FIG. 5 : [0080] Firstly, in a step S 21 , the control device 4 controls the roll stand 1 ′ to be integrated such that a rotational speed vU′ of the working rolls 3 ′ of the roll stand 1 ′ to be integrated corresponds to a setpoint exit speed v′* of the rolling stock 2 at the location of the roll stand 1 ′ to be integrated. In a step S 22 , the control device 4 then controls roll stand 1 ′ to be integrated such that the working rolls 3 ′ of the roll stand 1 ′ to be integrated are screwed down on the rolling stock 2 but the rolling stock 2 is not yet rolled in the roll stand 1 ′ to be integrated. The working rolls 3 ′ of the roll stand 1 ′ to be integrated thus merely revolve on the rolling stock 2 without rolling (that is to say deforming) the rolling stock 2 . [0081] In a step S 23 , the control device 4 begins to apply load to the roll stand 1 ′ to be integrated according to a defined temporal load application profile. Locally simultaneously to the application of load to the roll stand to be integrated, the control device 4 begins to relieve at least one other roll stand 1 , 1 ″ of the continuous rolling train of load according to a defined temporal load relief profile. The load application profile of the roll stand 1 ′ to be integrated and the load relief profile of the at least one other roll stand 1 , 1 ″ are coordinated with one another here such that the final properties of the rolling stock 2 are maintained. [0082] In a step S 24 , the control device 4 continues the application of load to the roll stand 1 ′ to be integrated according to the defined temporal load application profile. Here, the control device 4 controls the rotational speed vU′ of the working rolls 3 ′ of the roll stand 3 ′ to be integrated such that an exit speed v′ of the rolling stock 2 at the location of the roll stand 1 ′ to be integrated corresponds to the setpoint exit speed v′*. Here, the setpoint exit speed v′* may alternatively be temporally constant or temporally variable. [0083] In a step S 25 , the control device 4 continues the relief of load of the other roll stands 1 , 1 ″—similarly to the application of load to the roll stand 1 ′ to be integrated. It is also the case here that, during the determination of rotational speeds vU, vU″ of the working rolls 3 , 3 ″ of the corresponding roll stands 1 , 1 ″, the control device 4 takes into consideration the amounts of forward slip, which change corresponding to the respective instantaneous relief of load, of the rolling stock 2 . [0084] In a step S 26 , the control device 4 checks whether the roll stand 1 ′ to be integrated is already fully loaded. If this is not the case, the control device 4 returns to step S 24 , that is to say continues the load application process of the roll stand 1 ′ to be integrated and the corresponding load relief process of the other roll stands 1 , 1 ″. Otherwise, the integration of the roll stand 1 ′ to be integrated is—basically—complete. If necessary, however, any possibly remaining speed error may be eliminated in an additional step S 27 . [0085] If no roll stand 1 ″ is removed locally simultaneously to the integration of the roll stand 1 ′ to be integrated, the relief of load to be effected is generally distributed across a plurality of other roll stands 1 , 1 ″. In individual cases, however, it is possible for only a single other roll stand 1 , 1 ″ to be relieved of load. [0086] For a roll stand exchange, that is to say to implement the step S 7 of FIG. 2 and FIG. 3 , an approach is taken which is explained below in conjunction with FIG. 6 . Here, FIG. 6 is essentially a combination of the approaches of FIG. 4 and FIG. 5 . In detail: [0087] Steps S 31 and S 32 correspond to steps S 21 and S 22 of FIG. 5 . Steps S 33 and S 34 correspond to steps S 11 to S 13 of FIG. 4 or S 23 to S 25 of FIG. 5 . A step S 35 corresponds to the step S 14 of FIG. 4 . A step S 36 corresponds to the step S 27 of FIG. 5 . Steps S 37 to S 39 correspond to steps S 15 to S 17 of FIG. 4 . [0088] The substantial difference between the approaches of FIGS. 4 and 5 on the one hand and FIG. 6 on the other hand thus consists in that, in the approach of FIG. 6 , both the roll stand 1 ′ to be integrated is integrated and also the roll stand 1 ″ to be removed is removed, while in FIGS. 4 and 5 in each case only one of these measures is implemented. [0089] In the approach of FIG. 6 , there is generally a 1:1 correspondence between the integration of the roll stand 1 ′ to be integrated and removal of the roll stand 1 ″ to be removed. In individual cases, however, it is possible that, during the removal of the roll stand 1 ″ to be removed, the roll stand 1 ′ to be integrated is duly integrated, but load is nevertheless additionally applied to at least one of the roll stands 1 . Likewise, it is conversely possible that, during the integration of the roll stand 1 ′ to be integrated, one of the roll stands 1 is additionally relieved of load in addition to the removal of the roll stand 1 ″ to be removed. [0090] It is possible, to relieve the roll stand 1 ″ to be removed of load, for the control device 4 to control a rolling gap of the roll stand 1 ″ to be removed by position control. In this case, the load relief profile of the roll stand 1 ″ to be removed corresponds, as in FIG. 7 , to a temporal profile of a rolling gap setpoint value p* for the roll stand 1 ″ to be removed, which rolling gap setpoint value p* is increased from an initial value to a final value corresponding to the predetermined temporal profile as a function of the time t. At the initial value, the working rolls 3 ″ of the roll stand 1 ″ to be removed roll the rolling stock 2 . At the final value, the working rolls 3 ″ of the roll stand 1 ″ to be removed just no longer roll the rolling stock 2 , but merely revolve on the rolling stock 2 . [0091] Similarly, to apply load to the roll stand 1 ′ to be integrated, it is possible for the control device 4 to control a rolling gap of the roll stand 1 ′ to be integrated by position control. In this case, the load application profile of the roll stand 1 ′ to be integrated runs substantially inversely to the load relief profile of the roll stand 1 ″ to be removed. [0092] The initial value and final value of the rolling gap setpoint value p* may be specific to the stand. In particular, the value at which the working rolls 3 ′, 3 ″ merely revolve is dependent on the thickness of the rolling stock 2 at the location of the respective roll stand 1 ′, 1 ″. The value at which the rolling stock 2 is actively rolled, and therefore at which deformation of the rolling stock 2 takes place, may be dependent on the pass sequence. [0093] As an alternative to position control, to relieve the roll stand 1 ″ to be removed of load, it is possible for the control device 4 to control the rolling gap of the roll stand 1 ″ to be removed by force control. In this case, a setpoint rolling force F* with which the roll stand 1 ″ to be removed rolls the rolling stock 2 is reduced, as in FIG. 8 , according to a defined temporal profile from a relatively high initial value to a relatively low final value (zero or close to zero). At the high value, active rolling (deformation) of the rolling stock 2 takes place. At the low value, no plastic deformation of the rolling stock 2 takes place. [0094] Similarly, to apply load to the roll stand 1 ′ to be integrated, the control device 4 may control the rolling gap of the roll stand 1 ′ to be integrated by force control. The temporal load application profile is, according to FIG. 8 , substantially the inverse of the load relief profile of the roll stand 1 ″ to be removed. [0095] As a further alternative according to FIGS. 9 and 10 , to relieve the roll stand 1 ″ to be removed of load, it is possible for the control device 4 to control the rolling gap of the roll stand 1 ″ to be removed by correspondingly predefining a speed relationship r* relative to a roll stand 1 . Here, the roll stand 1 in question is positioned upstream of the roll stand 1 ″ to be removed and is likewise rolling the rolling stock 2 . Said roll stand is therefore not a roll stand 1 ′ to be integrated. In this case, corresponding to FIG. 10 , the control device 4 realizes a control block 10 to which are supplied firstly the speed relationship r* as a function of the time t and secondly the (measured or modeled) exit speeds v, v″ of the upstream roll stand 1 and of the roll stand 1 ″ to be removed. In the control block 10 , on the basis of the speed relationship r* and the exit speeds v, v″, the setpoint rotational speed vU* for the working rolls 3 of the upstream roll stand 1 and/or the setpoint rotational speed vU″* for the working rolls 3 ″ of the roll stand 1 ″ to be removed are determined such that the ratio of the exit speeds v, v″ is equal to the speed relationship r*. The setpoint rotational speeds vU, vU″* are correspondingly set—directly or for example by means of speed regulators 11 . Alternatively to the exit speeds v, v″, the corresponding setpoint exit speeds v*, v″* may also be taken into consideration. [0096] In the approach of FIG. 10 , it is additionally necessary for the tension ZA upstream of the roll stand 1 ″ to be removed to be adjusted to a predetermined setpoint tension Z*. This takes place in that the control device 4 realizes a tension regulator 12 which, by means of a corresponding corrective signal δs*, acts on the screw-down of the roll stand 1 ″ to be removed. Here, the tension ZA is measured by means of a suitable measuring element 13 . [0097] To relieve the roll stand 1 ″ to be removed of load, the speed relationship r* is, according to FIG. 9 , reduced gradually from a value greater than one to the value of one according to a predetermined temporal profile. In conjunction with the tension regulation, which acts on the screw-down of the roll stand 1 ″ to be removed, the degree of deformation is in this case set automatically. The corresponding approach is familiar to experts in the field of the cold-rolling of strips. [0098] The integration of the roll stand 1 ′ to be integrated may take place in a similar way. Only the temporal profile of the speed relationship r* must be correspondingly inverted, as in FIG. 9 . [0099] The roll stand 1 ′ to be integrated and the roll stand 1 ″ to be removed are generally integrated and removed in one and the same way, that is to say are both regulated either by position control or by force control or using the speed relationship r*. It is however theoretically also possible for the roll stand 1 ′ to be integrated and the roll stand 1 ″ to be removed to be regulated in different ways to one another. In this case, however, the coordination is more complex in terms of the details. [0100] Even if the relief of load of the roll stand 1 ″ to be removed or the integration of the roll stand 1 ′ to be integrated takes place by position or force control, the tension ZA in the section of the rolling stock 2 directly upstream of the respective roll stand 1 ′, 1 ″ must be regulated. This preferably takes place by virtue of a corrective value δv* being superposed on a rolling speed. The corrective value δv* may, according to FIG. 11 , be superposed by virtue of the control device 4 regulating the rotational speed vU′, vU″ of the roll stand 1 ′ to be integrated or of the roll stand 1 ″ to be removed. In this case, the control device 4 takes the adjustment of the rotational speed vU′, vU″ of the working rolls 3 ′, 3 ″ of the roll stand 1 ′ to be integrated and of the roll stand 1 ″ to be removed into consideration in at least one roll stand 1 which is likewise rolling the rolling stock 2 but is positioned downstream of the roll stand 1 ′, 1 ″ to be integrated or removed. [0101] It is alternatively possible for the control device 4 , using the corrective value δv*, to regulate the tension ZA in the section of the rolling stock 2 running into the corresponding roll stand 1 ′, 1 ″ by adjusting the rotational speed vU of the working rolls 3 of the roll stand 1 , which is positioned directly upstream of the respective roll stand 1 ′, 1 ″ and is likewise rolling the rolling stock 2 , and thereby correcting the rotational speed vU of said roll stand 1 . In this case, the control device 4 takes the adjustment of the rotational speed vU of the working rolls 3 of the roll stand 1 directly upstream into consideration in at least one further roll stand 1 in which the rolling stock 2 is likewise being rolled, with the latter roll stand 1 however being positioned only indirectly upstream of the roll stand 1 ′, 1 ″ to be integrated or removed. [0102] The present invention has numerous advantages. In particular, an integration and removal of roll stands 1 , 1 ′, 1 ″ is possible during ongoing operation of the continuous rolling train. The desired high availability of the continuous rolling train is therefore maintained despite the integration and removal. Rolling stock defects nevertheless do not arise during the integration and removal. The desired final dimensions and surface properties are maintained. No scrap is produced. [0103] The above description serves merely to explain the present invention. The scope of protection of the present invention should however be defined exclusively by the appended claims.

In mill stands of a continuous rolling train, a product passes through the train is rolled such that the product upon leaving the train has predetermined final characteristics. To remove one of the stands, the mill stand to be removed is completely relieved of load according to a defined temporal load relieving sequence. Locally simultaneously with the load relieving, at least one other mill stand is placed under load according to a defined temporal loading sequence. The load-relieving and loading sequence are mutually adjusted to preserve the final product characteristics. A circumferential roll velocity is controlled until the stand has been completely relieved such that a discharge velocity corresponds always to a predetermined desired discharge velocity. After the complete load-relieving, a correspondence of the circumferential roll velocity to the desired discharge velocity is maintained and the working rolls are lifted off. The mill stand is then deactivated.

BACKGROUND [0001] Current acceptable medical practice for treating diseases of body organs often involves surgical removal of the afflicted areas or surgical removal of the entire organ. For example, treatment of diseases and malignancies of the pancreas by surgical removal is particularly troublesome as the surviving patient has a limited life span. The pancreas is located behind the stomach and comprises two portions: one portion secretes digestive juices which pass into the duodenum; the other portion secretes insulin which passes into the bloodstream. The pancreas can become afflicted with two major types of tumors: ductal adenocarcinoma and endocrine tumors that can be either non-functioning tumors or functioning tumors. Non-functioning tumors can result in obstruction of the biliary tract or the duodenum, bleeding into the GI tract or be evidenced as abdominal masses. Functioning tumors can cause severe symptoms such as hypoglycemia, Zolinger-Elison syndrome, hypokalemia, carcinoid syndrome, and the like. When ductal adenocarcinoma is present, current treatment methods involve surgical removal of the affected areas it the cancer has not spread. Less than 2% of the patients undergoing this procedure survive for more than five years. When endocrine tumors are present, it is typical to surgically remove both the pancreas and the duodenum. In these instances, about 10% of the patients survive for five years. [0002] The largest internal organ, the liver performs over 100 separate bodily functions; and its sheer complexity makes it susceptible to almost as many different diseases. Liver disease is a broad term describing any number of diseases affecting the liver including, but not limited to, hepatitis, cirrhosis, haemochromatosis, cancer of the liver (primary hepatocellular carcinoma or cholangiocarcinoma and metastatic cancers, usually from other parts of the gastrointestinal tract), Wilson's disease, primary sclerosing cholangitis, primary biliary cirrhosis, budd-chiari syndrome, Gilbert's syndrome, glycogen storage disease type II, biliary atresia, alpha-1 antitrypsin deficiency, alagille syndrome, and progressive familial intrahepatic cholestasis. Some organ diseases (such as those of the pancreas and/or liver) have also been treated in situ with toxic agents such as chemotherapeutic agents and other therapeutic biological agents that are toxic moieties obtained from organic sources. However, it has been found that these agents cannot generally be introduced into the main blood circulation of the body in sufficient strength and/or quantity to achieve desired therapeutic responses in the affected organs as their negative toxic effects on other organs and tissues of the body off-set their potential positive therapeutic effect in the afflicted organ. SUMMARY OF THE INVENTION [0003] In one embodiment, the instant invention encompasses a catheter, comprising: a first expandable occlusion device and a second expandable occlusion device, expandable beyond a wall of the catheter, the first occlusion device and the second occlusion device spaced along the catheter for generating an occluded segment of the blood vessel between the first occlusion device and the second occlusion device when the first occlusion device and the second occlusion device are expanded, a lumen or catheter for removing uncontaminated blood from a location upstream of a first expandable occlusion device; and a lumen or catheter for reintroducing the uncontaminated blood into a subject downstream from the second expandable occlusion device. [0004] In another embodiment, the instant invention encompasses a catheter in which the device for removing is sized and dimensioned for placement in the renal vein. [0005] In another embodiment, the instant invention encompasses a catheter in which the extracorporeal circuit includes a filtration device for removing at least a portion of circulating hormones and/or other vasoactive agents present in the uncontaminated blood [0006] In another embodiment, the instant invention encompasses an apparatus, part of which is positionable in a blood vessel of a body having a blood flow therethrough, the catheter having a first expandable occlusion device and a second expandable occlusion device, expandable beyond a wall of the catheter, the first occlusion device and the second occlusion device spaced along the catheter for generating an occluded segment of the blood vessel between the first occlusion device and the second occlusion device when the first occlusion device and the second occlusion device are expanded, the improvement in the catheter comprising: a first port in the wall of the catheter, the first port positioned upstream, in the direction of the blood flow from the first occlusion device; a second port in the wall of the catheter, the second port positioned downstream, in the direction of the blood flow from the second occlusion device; a lumen within the catheter and having a first end and a second end, the first end connected to the first port and the second end connected to the second port for defining a bypass for blood in the blood flow for shunting the occluded segment of the blood vessels spaced and positioned for passing a portion of the blood from upstream in the direction of blood flow from the occlusion to downstream in the direction of blood from the occlusion; and an extracorporeal circuit comprising a lumen for removing uncontaminated blood from a location upstream of a first expandable occlusion device; a device for extracorporeally pumping the removed uncontaminated blood back into a subject; and a lumen or catheter for reintroducing the uncontaminated blood into a subject downstream from the second expandable occlusion device. [0007] In another embodiment, the instant invention encompasses a catheter comprising: a first lumen utilized to inflate/position a first occlusion device; a second lumen having perforations that may be utilized to convey blood draining into the occluded space between two inflated/positioned occluding device to an extracorporeal variable speed pump device and filtering device; a third lumen dimensioned and sized by providing a passage for blood to flow through from upstream to downstream of an occluded segment of the blood vessel; a fourth lumen that is connectable to an extracorporeal circuit for uncontaminated blood; and a fifth lumen that may be utilized to inflate/position a second occlusion device. [0008] In another embodiment, the instant invention encompasses an apparatus comprising: a first lumen utilized to inflate/position a first occlusion device; a second lumen having perforations that may be utilized to convey blood draining into the occluded space between two inflated/positioned occluding device to an extracorporeal variable speed pump device and filtering device; a third lumen dimensioned and sized by providing a passage for blood to flow through from upstream to downstream of an occluded segment of the blood vessel; a fourth lumen connected to an extracorporeal circuit for uncontaminated blood, wherein the extracorporeal circuit for uncontaminated blood comprises: a lumen for removing uncontaminated blood from a location upstream of a first expandable occlusion device; a device for extracorporeally pumping the removed uncontaminated blood back into a subject; and a lumen or catheter for reintroducing the uncontaminated blood into a subject; and a fifth lumen that may be utilized to inflate/position a second occlusion device. [0009] In another embodiment, the instant invention encompasses an apparatus comprising: a first lumen utilized to inflate/position a first occlusion device; a second lumen having perforations that may be utilized to convey blood draining into the occluded space between two inflated/positioned occluding device to an extracorporeal variable speed pump device and filtering device device; a third lumen connected to an extracorporeal circuit for uncontaminated blood, wherein the extracorporeal circuit for uncontaminated blood comprises: a lumen for removing uncontaminated blood from a location upstream of a first expandable occlusion device; and a lumen for extracorporeally pumping the removed uncontaminated blood back into a subject; a lumen or catheter for reintroducing the uncontaminated blood into a subject; and a fourth lumen that may be utilized to inflate/position a second occlusion device. BRIEF DESCRIPTION OF THE DRAWINGS [0010] For a fuller understanding of the disclosure, reference is made to the following description taken in conjunction with the accompanying drawing(s) in which: [0011] FIG. 1 shows a diagrammatic and schematic view of an embodiment of some of the main components of a system of the present invention in relationship to a body. [0012] FIG. 2 shows a partial cross-sectional side view of an embodiment of a double occlusion device catheter useful in the process of the invention. [0013] FIG. 3 shows a cross-sectional end view of the shaft of the double occlusion device catheter of FIG. 2 . [0014] FIG. 4 shows a cutaway cross-sectional side view of the interior of a double occlusion device catheter encompassed by the invention. [0015] FIG. 5 shows a partial cross-sectional side view of an embodiment of a cartridge-type blood filtration device for use with the system of the present invention. The cartridge includes an adsorbent material. [0016] FIG. 6 shows a partial cross-sectional side view of an embodiment of a hollow-fiber blood filtration device for use with the system of the present invention. [0017] FIG. 7 shows a partial cross-sectional side view of an embodiment of a double occlusion device catheter with active bypass segment as described herein. [0018] FIG. 8 shows a partial cross-sectional side view of an alternative embodiment of a double occlusion device catheter with active bypass segment as described herein. [0019] FIG. 9 shows a partial cross-sectional side view of an alternative embodiment of a double occlusion device catheter with active bypass segment as described herein. [0020] FIG. 10 shows a diagrammatic and schematic view of an embodiment of some of the main components of a system of the present invention in relationship to a body. [0021] FIG. 11 shows a diagrammatic and schematic view of an alternative embodiment of some of the main components of a system of the present invention in relationship to a body. DETAILED DESCRIPTION [0022] In one embodiment, the present invention relates to a system and method for the in situ treatment of organ disease using local delivery of therapeutic agents. A method for perfusing a high concentration of a therapeutic agent through a diseased organ of a body includes: perfusing a high concentration of a therapeutic agent therapeutic agent through the diseased organ, wherein the perfusion does not contaminate a general circulation of the body; removing contaminated blood from the organ, wherein the contaminated blood (whose concentration may be controlled by choice from zero to hundred percent by the filters) includes the therapeutic agent with effluent blood; transporting the contaminated blood to a blood filtration device; treating the contaminated blood in the blood filtration device to remove the contamination resulting in treated blood; returning the treated blood to the body. In another embodiment, the present invention further relates to providing a device for both passing upstream uncontaminated blood through the circulatory system past the occluded section of a particular blood vessel to a location in the blood vessel downstream to the occluded section; and mitigating effects on blood pressure that may result from the temporary occlusion of a blood vessel (in one embodiment, the inferior vena cava). The process may substantially prevent toxic levels of the therapeutic agent from entering the body's general circulation while delivering lethal doses of them to the diseased organ, and further provides for maintaining relative homeostasis of blood pressure despite the temporary occlusion of a major blood vessel. [0023] As used herein, the term “therapeutic agent” refers to an agent used to treat a diseased organ. For example, in treating cancers an antineoplastic agent, such as a chemotherapeutic agent, may be used. For example, for treating hepatitis an interferon, such as interferon-α- 2 b or interferon-α- 2 a may be used. Examples of therapeutic agents for use with the systems and methods of the present invention include, but are not limited to, Abarelix, Aldesleukin, Aldesleukin, Alemtuzumab, Alitretinoin, Allopurinol, Altretamine, Amifostine, Amifostine, Amifostine, Anakinra, Anastrozole, Arsenic trioxide, Asparaginase, Asparaginase, Azacitidine, Azacitidine, Bevacuzimab, Bexarotene capsules, Bexarotene gel, Bleomycin, Bortezombi, Bortezomib, Busulfan intravenous, Busulfan oral, Calusterone, Capecitabine, Carboplatin, Carmustine, Celecoxib, Cetuximab, Chlorambucil, Cisplatin, Cladribine, Clofarabine, Cyclophosphamide, Cytarabine, Cytarabine liposomal, Dacarbazine, Dactinomycin, Actinomycin D, Dalteparin sodium, Darbepoetin alfa, Dasatinib, Daunorubicin liposomal, Daunorubicin, Daunomycin, Decitabine, Denileukin, Denileukin Diftitox, Dexrazoxane, Docetaxel, Doxorubicin, Doxorubicin liposomal, Dromostanolone Propionate, Eculizumab, Elliott's B Solution, Epirubicin, Epirubicin HCL, Epoetin alfa, Erlotinib, Estramustine, Etoposide phosphate, Etoposide, VP-16, Exemestane, Fentanyl citrate, Filgrastim, Floxuridine (intraarterial), Fludarabine, Fluorouracil, 5-FU, Fulvestrant, Gefitinib, Gemcitabine, Gemcitabine, Gemcitabine HCL, Gemicitabine, Gemtuzumab Ozogamicin, Goserelin acetate, Histrelin acetate, Hydroxyurea, Ibritumomab tiuxetan, Idarubicin, Ifosfamide, Imatinib mesylate, Interferon, Interferon (pegylated), Interferon alfa-2a, Interferon alfa-2b, Irinotecan, lapatinib ditosylate, lenalidomide, letrozole, leucovorin, Leuprolide Acetate, Levamisole, lomustine, CCNU, Meclorethamine, Nitrogen mustard, Megestrol acetate, Melphalan, Melphalan L-PAM, Mercaptopurine, 6-MP, Mesna, Methotrexate, Methoxsalen, Mitomycin C, Mitotane, Mitoxantrone, Nandrolone phenpropionate, Nelarabine, Nofetumomab, Oprelvekin, Oxaliplatin, Paclitaxel, Paclitaxel protein-bound particles, Palifermin, Pamidronate, Panitumumab, Pegademase, Pegaspargase, Pegfilgrastim, Peginterferon alfa-2b, Pemetrexed disodium, Pentostatin, Pipobroman, Plicamycin, Mithramycin, Porfimer sodium, Procarbazine, Quinacrine, Rasburicase, Rituximab, Sargramostim, Sorafenib, Streptozocin, Sunitinib, Sunitinib maleate, Talc, Tamoxifen, Temozolomide, Teniposide, VM-26, Testolactone, Thalidomide, Thioguanine, 6-TG, Thiotepa, Topotecan, Topotecan HCL, Toremifene, Tositumomab, Tositumomab/I-131 Tositumomab, Trastuzumab, Tretinoin, ATRA, Uracil Mustard, Valrubicin, Vinblastine, Vincristine, Vinorelbine, Vorinostat, Zoledronate, and Zoledronic acid. [0024] As used herein, the term “occlusion device” denotes any of a variety of structures which may be reversibly inflated/positioned so as to occlude the blood vessel of a subject. Such structures include, but are not limited to, balloons; inflatable cuffs or sleeves; umbrella-shaped structures; fan-shaped structures; and all manners of fabric-covered wires or coils. [0025] In one example, the method of the invention may avoid the use of surgery to isolate the flow of contaminated blood and returns the same blood but in a more purified condition to a patient; and further provides for techniques to assist in maintaining homeostasis of the patient's blood pressure during the time when a particular blood vessel is temporarily occluded. As a result, the method of the invention may be used for extended periods of time. The method of the invention is applicable to the treatment of primary and metastatic tumors, including all forms and sizes of tumor, as well as other diseases of an organ of a human body. In an embodiment, the organ is a liver. In an embodiment, the organ is a pancreas. [0026] In an embodiment, the invention is directed to the treatment of tumors in the liver by the use of one or more antineoplastic agents, such as chemotherapeutic agents and/or biologicals, and the purification of venous blood from the liver to avoid systemic circulation of the agent(s). In an embodiment, the invention is directed to the treatment of hepatitis by the use of one or more therapeutic agents, such as interferon, and the purification of venous blood from the liver to avoid systemic circulation of the agent(s). In an embodiment, the invention is directed to the treatment of metastatic and primary cancers and tumors, including but not limited to, melanomas, adenocarcinomas, neuroendocrine tumors and hepatocellular carcinoma. [0027] For treating a diseased liver, these treatment modalities may involve the use of double occlusion device catheters that are suitable for insertion in the inferior vena cava to isolate venous outflow from the liver and permit the removal of blood contaminated with therapeutic agent from the body. The contaminated blood captured by the double occlusion device catheter is fed through tubing to a blood purification device, possibly via the aid of a pump. The method will be successful even if the therapeutic agent is not completely removed from the blood. In one embodiment the amount of therapeutic agent in the body is kept below toxicity levels. One hundred percent removal of any drug is seldom possible and generally not practical. [0028] In addition, these treatment modalities may involve the use of one or more accommodations so as to substantially maintain the normal flow of return blood in the occluded vessel and so as to facilitate homeostatis and management of blood pressure variations occasioned by the use of an occluding catheter in a major blood vessel. [0029] In one embodiment, an occlusion bypass lumen is provided. [0030] For treatment of tumors in the liver, because primary hepatocellular and metastatic hepatic tumors derive their blood supply from the hepatic artery, the tumor will be perfused by high concentrations of, for example, a chemotherapeutic agent. Because a normal liver receives three-fourths of its blood supply from the portal vein the agent will be diluted by a factor of about three before it reaches normal, uninvolved liver cells, thereby protecting them against hepatotoxicity. [0031] The method of the invention involves the percutaneous placement of unique double occlusion device catheter designs. Double occlusion device catheter designs useful in practicing the invention are disclosed in, but not limited to, U.S. Pat. No. 5,069,662; U.S. Pat. No. 5,411,479; U.S. Pat. No. 5,817,046; U.S. Pat. No. 5,897,566; U.S. Pat. No. 5,919,163; U.S. Pat. No. 6,186,146 (now Abandoned) and U.S. Pat. No. 7,022,097, the disclosures of which are hereby incorporated herein by reference. One function of the double occlusion device catheter is to isolate the flow of blood from the veins carrying the effluent blood from the diseased liver. Venous isolation precludes systemic perfusion of the contaminated blood. Thus the tip of the double occlusion device catheter is to be placed in the body so that the venous effluent from the diseased liver being treated is prevented from flowing to the heart. The space between the two-occlusion devices is predetermined to ensure removing the full quantity of contaminated blood from the treated diseased liver. The space between the occlusion device is large enough that the occlusion device central in position can be located in a position in the most central draining vein to block contaminated venous blood flow to the heart and the occlusion device peripheral in position can be located peripheral in the most central draining vein to block the flow of uncontaminated blood to the contaminated venous blood flow. Veins from organs not under treatment can enter the segment between occlusion devices without detrimental effect as long as the blood filtration device can accommodate the additional volume. The venous anatomy of the diseased liver under treatment or of adjacent organs can be altered where necessary by obstruction using angiographic embolisation or ablation techniques and materials, including detachable occlusion devices or stainless steel coils. [0032] The lumen of the catheter between the occlusion devices is openly connected, or can be made openly connected, to the surrounding vein. In addition, the same lumen of the catheter is also openly connected, or can be made openly connected, to the blood filtration device, thereby providing free flow of the contaminated blood from the veins to the blood filtration device. Thus the catheter has a main lumen to act as a conduit for the contaminated blood flow from the venous effluent(s) to the blood filtration device. [0033] The size of the main lumen is determined by the material of which it is made, the volume of blood to be transported through it and the diameter of the vein in which it will be located. The main lumen may be an open annulus or semi-annulus located within the peripheral occlusion device that is openly connected to the extracorporeal circuit. In this type of catheter, a central rod or rodlike axis is provided for support for the occlusion device. [0034] The catheter may also have supplemental lumina. The supplemental lumina are smaller in size, i.e., in diameter or cross-sectional area, than the main lumen. They may serve any of a number of ancillary functions in the process. For example, in one design, a supplemental lumen courses through the full length of the catheter for the purpose of accommodating a guidewire that is desirable for percutaneous insertion of the catheter. Each occlusion device may be provided with a supplemental lumen to be used for its inflation/positioning, or one supplemental lumen may be used for supplying fluid for the inflation/positioning of both occlusion devices. An additional supplemental lumen may be provided for connection to a pressure monitor to continuously measure the pressure of the venous effluent. This lumen can also be used to inject contrast medium, if provided with a connector that can accommodate an injection device. In some designs, the main lumen may be used for one or more of the above functions. This multifunctionality can serve to reduce the cost in making the catheter and simplify the apparatus. The main and/or supplemental lumina may be made from separate tubing threaded into the catheter or from channels molded into the structure of the catheter. Another supplemental lumen can be used to return detoxified blood to the general circulation and avoid puncture of another vein. [0035] The wall(s) of the segment of the catheter between the occlusion devices are provided with fenestrations to allow entry of venous blood into the main lumen. The number, shape and size of the fenestrations may vary according to the size of the catheter, the rate and volume of blood they must transmit, and the materials of construction of the catheter. The shape and size of the fenestrations should take into consideration turbulence effects as the blood courses though the fenestrations and into the main lumen. Fenestrations that are too small can elevate hepatic sinusoidal pressure and fenestrations that are too large may weaken the catheter walls and compromise the integrity of the catheter. [0036] One practical double occlusion device catheter design would have one large central lumen, 2 smaller lumina and 2 inflatable/positionable occlusion devices that are separated by about 9 to 10 cm. in the length of catheter that contains perforations. The catheter is designed to be positioned (under fluoroscopic guidance) in the inferior vena cava (IVC) such that the central occlusion device, when inflated/positioned, occludes the IVC just above the hepatic veins. The peripheral occlusion device, when inflated/positioned, occludes the IVC just below the hepatic veins, thus isolating hepatic venous blood from the systemic circulation. Perforations in the catheter between the two-inflated/positioned occlusion device convey blood through the large central catheter lumen to a variable speed pump and filtering device. An inferior vena cavagram through the main lumen can be used to document complete obstruction of the inferior vena cava proximal and distal to the hepatic veins. The effectiveness of passage of blood from the liver through the blood filtration device can be monitored by pressure measurement in the central catheter lumen. A variable speed pump may be adjusted to maintain normal hepatic vein pressure and flow. The detoxifying devices controllably reduce the agent in the blood to selected nontoxic levels before the blood is returned to the systemic circulation. [0037] In another design an independent return lumen courses through the main lumen. One end to the return lumen is connected to the outlet of the blood filtration device and the other end openly outlets into a vein at a location superior to the diaphragm. When the double occlusion device catheter is located in the IVC, this return lumen extends beyond the end of the main catheter to the right atrium. In this construction, the return lumen consists of a separate piece of tubing threaded inside the main lumen and through the end hole of the catheter. The return lumen is large enough to carry the full volume of the blood being returned to the patient from the blood filtration device. In another embodiment of the invention, part of the return flow of the effectively detoxified blood is fed through the return lumen and the remainder is separately fed to the patient via a separate feed system, such as through a separate catheter feed to one of the subclavian or jugular veins as described by Krementz, supra. [0038] The double occlusion device catheter, once properly located in the body, extends through the skin to the outside of the body. It terminates in a Luer fitting and a valve cutoff such as a stopcock. The blood filtration device can be separated from the double occlusion device catheter and reconnected at will. When the occlusion devices are not inflated/positioned, blood flow through the IVC is maintained. When the occlusion devices are inflated/positioned, the blood below the peripheral occlusion devices will find secondary pathways to the heart. [0039] This convenience may be duplicated on the supply side of the process, where the therapeutic agent is supplied to the arterial side of the liver, via the hepatic artery, by the percutaneous insertion of a feed catheter to the hepatic artery, leaving the tubular ending of the feed catheter in a plastic reservoir surgically implanted just below the patient's skin and surgically tied therein below the skin. The plastic reservoir contains a resealing membrane of a type similar to those used in multi-dose vials that can be percutaneously penetrated from the outside of the body by one or more needles to reinitiate the flow of therapeutic agent to the diseased liver. [0040] The double occlusion device catheter can be introduced into the femoral vein using the Seldinger technique. A guidewire made of stainless steel is first passed through a needle that has been inserted percutaneously into the vein. A catheter with a single occlusion device is inserted over the guidewire and the occlusion device is inflated/positioned to dilate the percutaneous tract to the diameter of the sheath that will transmit the double occlusion device catheter. A plastic sheath tubing is passed over the guidewire when the single occlusion device catheter is removed. After the sheath is properly located in the vein the double occlusion device catheter is inserted within the sheath and over the guidewire and advanced to the proper position relative to the organ to be treated. All manipulations of the double occlusion device catheter are done under fluoroscopic control. An inferior vena cavagram can be performed prior to catheter insertion or prior to occlusion device positioning/inflation with the patient lying on an opaque ruler, parallel to the IVC. The hepatic veins and renal veins can be identified and their location determined according to the opaque ruler. [0041] Under fluoroscopic guidance, the catheter is positioned so that the central occlusion device, when inflated/positioned, occludes the IVC just above the hepatic veins. The peripheral occlusion device, when inflated/positioned, occludes the IVC just below the hepatic veins. Dilute contrast medium such as saline solution is used to inflate/position the occlusion devices and reference to the ruler insures accurate positioning. [0042] In an embodiment of the invention, the double-occlusion device catheter contains three lumina. One lumen transmits an angiographic guidewire and is used for percutaneous insertion. A main lumen carries hepatic venous blood from the fenestrations between the occlusion devices to the blood filtration device. The third lumen terminates at the fenestrations and is used to measure pressure or inject contrast medium. A pressure monitor, attached to this lumen, measures pressure within the isolated segment of the vena cava before and during occlusion device inflation. The pressure measured before occlusion device inflation/positioning is the systemic venous pressure. The pressure measured after occlusion device inflation/positioning but before opening the blood filtration device is equal to the wedge hepatic venous pressure, which is assumed to be equal to portal pressure. This measurement can determine the presence or absence of portal hypertension. The pressure measured after occlusion device inflation/positioning and during flow through the blood filtration device is the hepatic venous pressure. The hepatic venous pressure can be monitored continuously during drug infusion. If a pump is used, the speed of the pump can be adjusted to maintain hepatic venous pressure above systemic venous pressure but below portal pressure. This prevents hepatic sinusoidal congestion. The calibers of the occlusion device catheter and of the tubing in the blood filtration device are calculated to ensure that they are of sufficient size to transmit the necessary volumes of blood with minimal resistance. [0043] After inflation/positioning of the occlusion devices, an inferior vena cavagram (contrast medium injected into the inferior vena cava) is typically performed through the double occlusion device catheter prior to infusion to document complete obstruction of the vena cava proximal and distal to the hepatic veins and to demonstrate the anatomy of the hepatic veins. Samples of hepatic venous blood are generally aspirated through the pressure port of the double occlusion device catheter immediately after the beginning of infusion, and, in the typical case, at intervals not to exceed one hour during infusion, and for at least three hours after infusion, the samples are analyzed for therapeutic agent concentrations. Simultaneous blood samples are taken from the blood filtration device after detoxification and analyzed for drug concentrations in order to document the efficiency of the detoxification device in removing the drug from the blood before returning the blood to the systemic circulation. In addition, blood samples are obtained from a peripheral vein to evaluate drug concentrations reaching the systemic circulation. Systemic drug concentrations are then measured over 24 to 48 hours following the infusion. [0044] Another double occlusion device catheter design may utilize only 2 supplemental lumina and one main lumen for blood transfer to the blood filtration device. Each supplemental lumen can supply fluids to one of the occlusion devices. [0045] The venous pressure may provide the pressure for passage of blood to the blood filtration device. In an embodiment, a pump may be used in order to continue the movement of blood though the blood filtration device and return it to the patient. The blood is removed from the body by a combination of gravitational displacement and the venous blood pressure. The pump does not generate a negative pressure and pull blood from the body. The pressure of the return flow of the blood from the blood filtration device to the systemic venous system should be less than about 300 mm Hg. [0046] A variety of suitable pumps are commercially available. They come in a number of designs. A preferred design is a centrifugal cardiopulmonary bypass pump that utilizes smooth surface rotators without relying on rotating vanes. These pumps have been used in long term support of cardiac bypass and in liver transplants. Such designs are shown in U.S. Pat. No. 3,487,784; Reissue 28,742; U.S. Pat. No. 3,647,324; U.S. Pat. No. 3,864,055; U.S. Pat. No. 3,957,389; U.S. Pat. No. 3,970,408 and U.S. Pat. No. 4,037,984. [0047] With respect to FIG. 1 , there is shown the main components of a system for the in situ treatment of liver disease using local deliver of therapeutic agents, with relation to a human body 2 . A liver 3 is supplied with therapeutic agents from a syringe 4 through tubing leading to a catheter 6 located in a hepatic artery 5 . Hepatic venous blood containing concentrations of therapeutic agent (i.e., contaminated blood) is passed via hepatic veins to a double occlusion device catheter 9 located in the inferior vena cava (IVC). The occlusion devices of the double occlusion device catheter 9 are positioned central and peripheral of the hepatic veins. The contaminated blood is passed through the double occlusion device catheter 9 to tubing 17 to a point exterior to the body 2 , then optionally to a pump 21 . The pump 21 moves the contaminated blood through an extracorporeal circuit at relatively constant low pressure, the object being to avoid raising or lowering the fluid pressure of the total circuit ranging from the hepatic veins through the return to the body. The contaminated blood is transported through tubing 41 into a blood purification device 43 , which will be described in more detail below, to detoxify the blood. The detoxified blood is passed through tube 44 to effect infusion through the subclavian vein (not shown) by standard procedures in the art. [0048] With respect to FIG. 2 , there is shown an embodiment of a double occlusion device catheter 100 of the present invention. Catheter 100 includes slotted fenestrations 104 in a solid plastic tubing 102 . An open end 118 terminates the catheter 100 . Open end 118 is tapered to the caliber of an angiographic guide wire that will, under fluoroscope control, allow the catheter 100 to be advanced from the femoral vein to the proper location in the inferior vena cava without risk of injury to the interior of the vessels. Appropriate guide wires may be, for example, 0.035, 0.038, or 0.045 inch in diameter. During treatment, the catheter end hole is closed using a standard angiographic apparatus (tip occluding wire), that consists of a thin wire long enough to traverse the length of the catheter at the end of which is a stainless steel bead just large enough to obstruct the catheter's end-hole when advanced into it (similar to a metal stopper that closes the outlet from a sink when advanced). [0049] Alternatively, the end hole 118 may accommodate a return catheter. The return catheter can be used to return treated blood to the systemic circulation. The return catheter is advanced over a guide wire through the main lumen of the double occlusion device catheter 100 and through the end hole 118 into the right atrium or superior vena cava. The return catheter can be made to gradually taper its O.D. by decreasing its wall thickness, leaving the I.D. constant, since the location of the tip of the return catheter is not critical. The length over which the catheter tapers is arbitrary. The taper is constructed so that the tip of the catheter is its narrowest O.D. and the O.D. increases toward the femoral vein. As this return catheter is advanced through the lumen of the main catheter 100 the tip easily passes through the end hole 118 of the double occlusion device catheter 100 . The tapered end of the return catheter is advanced until it obstructs the end hole 118 , preventing systemic blood from entering the double occlusion device catheter 100 when the occlusion device are inflated/positioned but leaving an open lumen through the return catheter to return blood beyond the isolated venous segment without mixing with contaminated blood. [0050] The catheter tubing 102 can be made of a variety of plastic materials such as polypropylene, polyethylene, polyvinylchloride, ethylene vinylacetate copolymers, polytetrafluoroethylene, polyurethane, and the like. Favorable plastic combinations for catheters containing a return lumen are a homogeneous mixture of high-density polyethylene and linear low-density polyethylene. That combination gives favorable stiffness at ambient conditions and allows the use of especially thin wall thicknesses. When the surface of the catheter is made of a plastic that is difficult to bond with a occlusion device, the plastic may be treated first by one or more of a number of well known methods that make bonding possible. The methods include plasma treatment, ozone treatment, and the like. Occlusion devices 110 and 114 may be made from a plurality of materials. The occlusion devices may be adhesively bonded at sheath surfaces 108 and 112 , respectively. A wide variety of adhesives may be employed. Polyacrylonitrile type adhesives, rubber latex adhesives and the like may be used to secure the occlusion device to the sheath surfaces 108 and 112 . [0051] With respect to FIG. 3 , there is shown a cross section of the catheter 100 shown in FIG. 2 . The interior of the catheter 100 contains a main lumen 120 and 4 additional lumina 124 molded into an outer wall. The additional lumina 124 can be used for the various functions described above. [0052] FIG. 4 provides a more detailed schematic cross sectional side view of an embodiment of a double occlusion device catheter 161 . In this depiction, a catheter sidewall 163 is penetrated by a plurality of fenestrations 165 . A main lumen 169 contains at its periphery supplemental lumina 170 , 171 and 173 . Supplemental lumens such as depicted at 170 and 171 may be closed at their distal end or may completely traverse the double occlusion device section of the catheter, with a distal opening distal to the occlusion device 167 . These supplemental lumina may be utilized for any of a variety of functions. For example and without limitation, supplemental lumina 170 and 171 can be used to accommodate a guidewire and/or pressure monitor. Lumen 173 may optionally be utilized so as to inflate/position occlusion means 166 and 167 . [0053] Supplemental lumina 170 and 171 may also be utilized as a “shunt”, or bypass, as follows. A port or opening 178 may be provided in the wall of the catheter, just upstream (in the direction of blood flow) from the occlusion device 166 . The port 178 may connect to a lumen 171 that extends towards the tip of the catheter, the second end of the lumen 171 positioned in the wall or the tip of the catheter just downstream or anterior to the occlusion device 167 , and the second end of the lumen 171 may be provided with a second port. The two ports and the connecting lumen 171 form a shunt or bypass for the blood flowing through the vessel and blocked by the inflated/positioned occlusion devices 166 and 167 . With a blood bypass, such as shown and described as part of the occlusion device catheter, isolation of the body part from the blood supply in the vessel is achieved without interfering with the flow of blood through the blood vessel. [0054] By providing a device for uninterrupted flow of blood from upstream relative to the direction of blood flow from the obstructed segment of blood vessel to downstream relative to the direction of blood flow from the obstructed segment, the bypass mitigates the buildup of excess blood volume in the occluded blood vessel upstream of the occlusion. As blood vessels are pressure sensitive and maintain appropriate tone and resultant blood pressure at least in part through signals generated by vessel wall baroreceptors, mitigating the amount of excess blood pooling upstream of the occlusion through use of such a bypass device provides a method of minimizing the effect on baroreceptor signaling of excess, pooled blood upstream of the occluded vessel segment; and/or provides a method whereby blood rich in certain vasoactive substances (for example, renin and/or catecholamines) may be rapidly re-routed around the occluded section of the inferior vena cava or other occluded blood vessel [0055] Remaining lumina, such as those in communication with openings 175 and 177 , may be utilized to supply air and/or fluid to occlusion devices 166 and 167 . [0056] In one embodiment, the system and method of the present invention relies on the double occlusion device catheter for substantially preventing contaminated blood from entering the general circulation, as well as the blood purification device for the detoxification (treatment) of the contaminated blood. In an embodiment, the blood purification device is a cartridge, of any shape, consisting of a plastic or other material secured with two ends with ports allowing for catheter attachment. The blood purification device can further include additional ports. FIG. 5 shows a side cross-sectional view of a general cartridge-type blood purification device 80 for use with the system of the present invention. The blood purification device 80 is composed of an aggregate of blood-compatible adsorbent material 82 , composed of natural, synthetic or chemical materials and which may optionally possess natural or artificially enhanced adsorbent characteristics. The blood-compatible adsorbent material 82 may be made further compatible by way of chemical, synthetic or other method of modification or coating of the adsorbent material 82 while minimally affecting adsorbent's 82 affinity characteristics. The combination of surface coating and adsorbent 82 creates a more effective filter which is less harmful to the blood and may provide additional benefits. In an embodiment, the blood purification device 80 is used to remove the chemotherapeutic agent Melphalan from contaminated blood. The blood purification device 80 may remove at least 1.5 mg/kg Melphalan from human blood and is capable of flow rates exceeding about 500 ml/minute/device. In other embodiments, the flow rates can vary. Drug removal will ideally begin at 90-100% removal rates, and gradually decrease in efficiency as the infusion progresses. In other embodiments, the efficacy will remain constant throughout the detoxification process. Total efficiency for drug removal will be between about fifty and about one-hundred percent of drug delivered. [0057] As shown in the embodiment depicted in FIG. 6 , a blood purification device 90 is a hollow-fiber device. The blood purification device 90 comprises a canister cartridge consisting of, within a hollow portion of the cartridge, hollow fibers 92 connected to each end ( 93 and 95 ) of the cartridge, whereby treated blood flows through the hollow fibers 92 in one direction, from end to end, and whereby the hollow fibers 92 within the cartridge are surrounded by a natural, synthetic or chemical based adsorbent material 94 which assists in the adsorption of the agents from the treated blood. The cartridge possesses a flow through capability external to the hollow fibers 92 and internal of the cartridge, to continually flush the adsorbent material 94 of the blood purification device 90 , allowing for increased adsorption capability by way of preventing saturation. The flow through capability is achieved by two ports ( 97 and 99 ) on each end of the cartridge attached to tubes 96 for the continuous one way flow of a flushing agent 98 . In an embodiment, flow direction of the treated blood, hollow fibers 92 , and flushing agent 98 can vary. The hollow fibers 92 are composed of a porous material, allowing for the pass through of the therapeutic agent for the adsorption by surrounding adsorbent material 94 . Membrane permeability is assisted by way of negative pressure, fluctuating pressure or other device of pressure gradient or circular flow. In an embodiment, the membrane permeability, method of permeability and composition can vary. The adsorbent material 94 is composed of natural, synthetic or chemical materials and may possess natural or artificially enhanced adsorbent characteristics. In an embodiment, the blood purification device 90 is used to remove the chemotherapeutic agent Melphalan from contaminated blood. The blood purification device 90 may remove at least 1.5 mg/kg Melphalan from the human blood and is capable of flow rates exceeding about 500 ml/minute/device for a period of time not less than about one minute and not more than about four hours. In additional embodiments, the flow rate and absorption efficacy can vary. Devices 90 are capable of being run simultaneously in parallel, and singly, whereby a single device 90 will possess the capacity to handle the adsorption, pressure, and other requirements of it, alone. At least two devices 90 are capable of being run laterally to each other, end-to-end in series, with an adaptor connecting the two devices 90 , whereby the adaptor is designed specifically for connecting the devices 90 . A variety of adsorbent slurries can be used in this device 90 depending on which therapeutic agent is trying to be extracted. Different slurries can be used in each device 90 if run laterally. Reconstitution could occur in the second device 90 if run laterally. The effect of using hollow fibers 92 through the device 90 with the adsorbent material 94 surrounding the hollow fibers 92 , creates a synergistic and maximized filtration of therapeutic drug agent. [0058] Suitable adsorbent materials for use with any of the blood purification devices of the present invention include, but are not limited to, carbon-based adsorbent materials, coated or uncoated with a biocompatible synthetic, natural or chemical coating or modification, geared to minimize impact on the blood while minimally affecting the adsorbent characteristics of the carbon-based adsorbent. Such coating may include, for example, methyl methacrylate. Adsorbents may be prepared by coating crushed carbon originated from vegetables (hereinafter referred to as the coated crushed active carbon), for example, or an active carbon made of carbonized shell of coconut (hereinafter referred to as the coated coconut active carbon). Coated crushed active carbon may be prepared, for example, by dipping the original carbon into an ethyl alcohol-ethyl ether solution of pyroxylin, and drying the same. Coated coconut active carbon may be prepared, for example, by coating the original carbon into an ethyl alcohol-ethyl ether solution of pyroxylin via a phase separation process using dioxan as a solvent. [0059] The blood purification device may use a coated bead-shaped activated carbon for the purification of the blood, which is prepared by coating a beads-shaped activated carbon with a film-forming material. The bead-shaped activated carbon that may be used in the blood purification device of the present invention is an active carbon having a nearly perfect sphere form, which is obtained from pitch as a source material through melt molding, that is, a process for the molding of melted material. The bead-shaped activated carbon is different from conventional crushed or granulated active carbon. More particularly, the bead-shaped activated carbon can be prepared by, for example, dispersing the pitch in melted state into water to form a sphere, making the sphere non-fusible and carbonizing the same. As for detailed descriptions of the preparation for the bead-shaped activated carbon, refer to Japanese Patent Publication Nos. 25117/74 and 18879/75, for example. Such bead-shaped activated carbon is available in the market under the name of bead-shaped activated carbon (BAC) [Trade Mark, manufactured and sold by Taiyokaken Kabushiki Kaisha in Japan]. The film-forming material is selected from the materials which may provide a semipermeable film, including, but not limited to, pyroxylin, polypropylene, copolymer of vinyl chloride-vinylidene chloride, ethylene glycol polymethacrylate, collagen, and the like, for example. A conventional process may be employed for coating the beads-shaped activated carbon with the film-forming materials. Examples of such processes include, but are not limited to, pan coating, air suspension coating, spray drying, and the like. As a solvent to be employed for dissolving the film-forming material in the coating process, it is desirable to use a solvent which can be easily removed at a drying step, and has a low toxicity even if the solvent is dissolved into the blood. In view of this point, ethanol is an especially preferred solvent, when pyroxylin is used for the film-forming material. [0060] When the coated bead-shaped activated carbon is used for the purification of the blood, it may be desirable to further coat the coated bead-shaped activated carbon. The activated carbon may be further coated with methyl methacrylate or albumin. In additional embodiments, varying adsorption compositions may be used other than carbon-based. [0061] Any of the blood purification devices of the present invention may utilize, in addition to the carbon-based binding characteristics, biotin-avidin, antibody-antigen, and/or other protein affinity interactions. These interactions rely on the process of tagging the therapeutic agent with the biotin and tagging the adsorbent material of the blood purification device with opposite attracting agent, avidin, whereby the binding of the avidin to the carbon has minimal negative impact on the adsorbent characteristics. In other embodiments, varying affect on the binding and affinity and adsorption characteristics may be had. This method of blood filtration relies on both carbon adsorption and biotin-avidin attraction. In additional embodiments, interactions based on affinity relationships other than biotin-avidin may be utilized. The effect of combining the protein-based affinity characteristics with the preexisting adsorbent characteristics and the double occlusion deviceocclusion device catheters of the invention creates a highly effective and maximized method of drug filtration from blood. Such filtration technologies may also optionally be applied to the removal of certain agents, for example, vasoactive or other biologically active agents, from the blood. [0062] FIGS. 7-9 provide more detail as to a second, alternative and/or complementary device of providing for bypass of uncontaminated blood from upstream to downstream of the occluded vessel section; and/or for controlling blood pressure disturbances that may be occasioned by such occlusion. [0063] FIG. 7 discloses a five-lumen catheter device. First lumen 301 may be utilized to inflate/position a first occlusion device 110 . Second lumen 302 has perforations 104 that may be utilized to convey blood draining into the occluded space between the two inflated/positioned occluding devices 110 , 114 to an extracorporeal variable speed pump and filtering device (not shown). Third lumen 303 is a bypass lumen, open at both ends, that may shunt the occluded section of a blood vessel by providing a passage for blood to flow through from upstream to downstream of the occluded segment of the blood vessel. Fourth lumen 304 is a bypass lumen that is connectable to an extracorporeal circuit for uncontaminated blood, as described in further detail below, and that is optionally dimensioned and sized so as to accommodate an adequate blood flow rate for upstream blood draining into the inferior vena cava that must be bypassed around the occluded section of the inferior vena cava. Fifthlumen 305 may be utilized to inflate/position a second occlusion device 114 . [0064] FIG. 8 discloses a five lumen catheter device. First lumen 301 may be utilized to inflate/position a first occlusion device 110 . Second lumen 302 has perforations that may be utilized to convey blood draining into the occluded space between the two inflated/positioned occluding device 110 , 114 to an extracorporeal variable speed pump and filtering device (not shown). Third lumen 303 is a bypass lumen, open at both ends, that may shunt the occluded section of a blood vessel by providing a passage for blood to flow through from upstream to downstream of the occluded segment of the blood vessel. Fourth lumen 304 is a bypass lumen that is connected to an extracorporeal circuit for uncontaminated blood having a device for collecting upstream blood 306 , as described in further detail herein. Fifth lumen 305 may be utilized to inflate/position a second occlusion device 114 . [0065] FIG. 9 discloses a four-lumen catheter device. First lumen 301 may be utilized to inflate/position a first occlusion device 110 . Second lumen 302 has perforations that may be utilized to convey blood draining into the occluded space between the two inflated/positioned occluding device 110 , 114 to an extracorporeal variable speed pump and filtering device (not shown). Third lumen 304 is a bypass lumen that is connected to an extracorporeal circuit for uncontaminated blood having a device for collecting upstream blood 306 , as described in further detail below. Fourth lumen 305 may be utilized to inflate/position a second occlusion device 114 . [0066] FIG. 10 depicts one embodiment of the instant invention in operation. A liver 3 is supplied with therapeutic agents from a syringe 4 through tubing leading to a catheter 6 located in a hepatic artery 5 . Hepatic venous blood containing concentrations of therapeutic agent (i.e., contaminated blood) is passed via hepatic veins to a double occlusion device catheter 9 located in inferior vena cava (IVC) 1 . The occlusion device of the double occlusion device catheter 9 are positioned central and peripheral of the hepatic veins. The contaminated blood is passed through the double occlusion device catheter 9 to tubing 17 to a point exterior to the body 2 , then optionally to a pump 21 . The pump 21 optionally moves the contaminated blood through an extracorporeal circuit at relatively constant low pressure, the object being to avoid raising or lowering the fluid pressure of the total circuit ranging from the hepatic veins through the return to the body. The contaminated blood is transported through tubing 41 and optionally flows through a blood purification device 43 , which will be described in more detail below, to detoxify the blood. The detoxified blood is passed through tube 44 to effect infusion through the subclavian vein (not shown) by standard procedures in the art. [0067] Renal venous blood is passed via renal veins to a catheter collection device 8 located in or proximal to a renal vein, upstream of the double occlusion catheter. The collection device of an excess upstream blood collection catheter 10 is positioned proximal to at least one renal vein. This collected renal blood is passed to a point exterior to the body 2 , then optionally to a pump 21 . The pump 21 , which may be the same pump as that used for the contaminated blood circuit or a separate unit (not shown), moves the renal venous blood through an extracorporeal circuit at relatively constant low pressure, the object being to avoid raising or lowering the fluid pressure of the total circuit ranging from the renal veins through the return to the body. The pump 21 is optionally designed so as to accommodate an adequate blood flow rate for upstream blood draining into the inferior vena cava that must be bypassed around the occluded section of the inferior vena cava. The renal venous blood is transported through tubing 42 , optionally into a blood purification device 45 , which will be described in more detail below, which may optionally remove compounds of interest (in one embodiment, renin, catecholamines and/or other vasoactive substances or constituents of the renin-angiotensin-aldosterone axis) from the renal venous blood. The filtered renal venous blood is passed through tube 11 and is returned to the patient downstream of the occluded blood vessel segment via return lumen 304 , which lumen may optionally extend proximate to the corresponding atrium. [0068] FIG. 11 depicts an alternate embodiment of the instant invention in operation. A liver 3 is supplied with therapeutic agents from a syringe 4 through tubing leading to a catheter 6 located in a hepatic artery 5 . Hepatic venous blood containing concentrations of therapeutic agent (i.e., contaminated blood) is passed via hepatic veins to a double occlusion device catheter 9 located in inferior vena cava (IVC) 1 . The occlusion device of the double occlusion device catheter 9 are positioned central and peripheral of the hepatic veins. The contaminated blood is passed through the double occlusion device catheter 9 to tubing 17 to a point exterior to the body 2 , then optionally to a pump 21 . The pump 21 moves the contaminated blood through an extracorporeal circuit at relatively constant low pressure, the object being to avoid raising or lowering the fluid pressure of the total circuit ranging from the hepatic veins through the return to the body. The pump 21 is optionally designed so as to accommodate an adequate blood flow rate for upstream blood draining into the inferior vena cava that must be bypassed around the occluded section of the inferior vena cava. The contaminated blood is transported through tubing 41 into a blood purification device 43 , which will be described in more detail below, to detoxify the blood. The detoxified blood is passed through tube 44 to effect infusion through the subclavian vein (not shown) by standard procedures in the art. [0069] Renal venous blood is passed via renal veins to a catheter collection device 8 located in a renal vein, upstream of the double occlusion catheter. The collection device of an excess upstream blood collection catheter 10 is positioned proximal to at least one renal vein. The collected renal blood is passed to a point exterior to the body 2 , then optionally to a pump 21 . The pump 21 , which may be the same pump as that used for the contaminated blood circuit or a separate unit (not shown), moves the renal venous blood through an extracorporeal circuit at relatively constant low pressure, the object being to avoid raising or lowering the fluid pressure of the total circuit ranging from the renal veins through the return to the body. The renal venous blood is transported through tubing 42 , optionally into a blood purification device 45 , which will be described in more detail below, which may optionally remove compounds of interest (in one embodiment, renin and other angiotensive hormones) from the renal venous blood. The filtered renal venous blood is passed through tube 11 and is returned to the patient to effect infusion 22 through a remote blood vessel (not shown) by standard procedures in the art. [0070] The extracorporeal bypass loop consists of the following components: device ( 304 ) for returning uncontaminated blood to the subject. Of note, such a return may be directly to the downstream side of downstream occlusion device 114 or may be to a remote location, e.g. a jugular vein or proximal to the atrium (akin to the return of treated blood shown at FIG. 11 , 22 ). The device 304 is optionally designed so as to accommodate an adequate blood flow rate for upstream blood draining into the inferior vena cava that must be bypassed around the occluded section of the inferior vena cava. optional pump ( 21 ) for pumping renal venous blood from its removal point to its return point. Of note, such a pump may be a second, standalone pump or may be a dual-purpose pump that both circulates renal venous blood in the uncontaminated extracorporeal circuit and circulates contaminated blood in a second, extracorporeal circuit. The pump 21 is optionally designed so as to accommodate an adequate blood flow rate for upstream blood draining into the inferior vena cava that must be bypassed around the occluded section of the inferior vena cava. optional filtering device ( 45 ) for filtering uncontaminated blood, in line with the renal venous extracorporeal bypass circuit. device 306 for withdrawal of uncontaminated blood from a location upstream from occlusion device 110 in FIG. 4 . [0075] In operation, withdrawal device 306 is placed in a location of a catheter-occluded blood vessel upstream of the occlusion. The withdrawal device 306 may optionally be placed by insertion in a femoral vein or artery not utilized in placement of the double occlusion device catheter. Uncontaminated blood flows into the withdrawal device 306 , is optionally pumped 21 through an extracorporeal circuit and is reintroduced to the subject either through a lumen opening downstream of occlusion device 304 or at a site remote from the occlusion, e.g. as shown and described in FIG. 11 , 22 . [0076] In another embodiment, withdrawal device 306 is sized and dimensioned so as to be specifically placed proximate to or within the renal vein. [0077] Renin is a peptide hormone that is secreted by the kidney from specialized cells called granular cells of the juxtaglomerular apparatus in response to: A decrease in arterial blood pressure (that could be related to a decrease in blood volume) as detected by baroreceptors (pressure sensitive cells). This is the most causal link between blood pressure and renin secretion (the other two methods operate via longer pathways). A decrease in sodium chloride levels in the ultra-filtrate of the nephron. This flow is measured by the macula densa of the juxtaglomerular apparatus. Sympathetic nervous system activity, that also controls blood pressure, acting through the β 1 adrenergic receptors. [0081] Renin acts to hydrolyze angiotensin, resulting in increased plasma levels of angiotensin 1 and a downstream result of increased blood pressure occasioned by vasoconstriction. [0082] Catecholamines are sympathomimetic “fight-or-flight” hormones that are released by the adrenal glands in response to stress. They are part of the sympathetic nervous system, are found in the renal vein microenvironment, and can cause increased heart rate and increased blood pressure. [0083] Renin, catecholamine, and/or other vasoactive substance levels may be increased as a physiological response to occlusion of a blood vessel and/or extracorporeal filtration of contaminated blood, both of which may be accompanied by a drop in blood pressure. Withdrawal device 306 may optionally be placed by insertion in a femoral vein or artery not utilized in placement of the double occlusion device catheter. Uncontaminated blood from the renal vein that may have elevated levels of renin, catecholamines and/or other vasoactive substances flows into the withdrawal device 306 , and may be pumped 21 through an extracorporeal circuit. Optional in-line filter device 45 may be utilized to filter out components of the plasma found in the renal vein microenvironment, utilizing techniques described elsewhere in the instant application; or, alternately, the extracorporeal circuit may function to ensure that plasma levels of renin and/or catecholamines found in the renal vein microenvironment are more quickly delivered to the remaining systemic circulation by providing a high-throughput bypass around the occluded segment of the inferior vena cava. The uncontaminated, optionally filtered blood is reintroduced to the subject either through a lumen opening downstream of occlusion device 304 or at a site remote from the occlusion, e.g. as shown and described in FIG. 11 , 22 . Rapid return of renal vein microenvironment renin and/or catecholamines to the systemic circulation may result in an increased systemic circulation plasma level of these hormones and result in an improved ability of the subject to maintain blood pressure homeostasis by responding to a drop in blood pressure occasioned by occlusion of the inferior vena cava and/or filtration of blood in an extracorporeal circuit. [0084] Though this invention has been described with emphasis on the treatment of liver disease resulting from cancer and viruses, it is quite apparent that the invention has broader application. The invention is useful for the treatment of any organ in which the treating agent would cause toxological effects if it entered the body's general circulation. For example, the invention could be applied to the treatment of infectious diseases of organs such as fungal diseases. A specific illustration would be the treatment of hepatic fungal infections with Amphotericen B. The procedures described above would be directly applicable to extracorporeal recovery of this agent and its isolation from entering the general circulation of the body during treatment of the liver with significant concentrations of this drug. [0085] Therefore, the breadth of the invention encompasses the perfusing of a high concentration of an agent to treat an organ, such as anti-cancer agents through a body organ containing a tumor, without their entering the body's general circulation, removing them from the organ with effluent blood and transporting the contaminated blood to an extracorporeal blood purification device where the blood is treated to remove the contamination, and returning the treated blood to the body. The process prevents toxic levels of the agents from entering the body's general circulation while delivering lethal doses of the agents to the tumor. While illustrative embodiments of the invention are disclosed herein, it will be appreciated that numerous modifications and other embodiments may be devised by those skilled in the art. Therefore, it will be understood that the appended claims are intended to cover all such modifications and embodiments that come within the spirit and scope of the present invention.

The instant invention encompasses a catheter, comprising: a first expandable occlusion device and a second expandable occlusion device, expandable beyond a wall of the catheter, the first occlusion device and the second occlusion device spaced along the catheter for generating an occluded segment of the blood vessel between the first occlusion device and the second occlusion device when the first occlusion device and the second occlusion device are expanded, a lumen or catheter for removing uncontaminated blood from a location up-stream of a first expandable occlusion device; a lumen or catheter for reintroducing the uncontaminated blood into a subject downstream from the second expandable occlusion device; apparati encompassing the above technology; and methods of use incorporating same.

CROSS-REFERENCE TO RELATED APPLICATION(S) [0001] is application is a National Phase Patent Application and claims the priority of International Application Number PCT/CN2006/003014, filed on Nov. 10, 2006, which claims priority of Chinese Patent Application Number 200610095384.0, filed on Jan. 11, 2006. FIELD OF THE TECHNOLOGY [0002] The present invention relates to device and method for preparing filament yarn of composite nanofibers. It belongs to the technical field of manufacturing special fibers. BACKGROUND OF THE INVENTION [0003] With social development and improvement of people's lives, fiber industry has faced great challenges in recent years as single components could not meet the requirement of fibers with more functions. Various types of composite fibers have been developed, such as core-sheath, filling, bilateral, sea-island and other types of composite fibers. US Patent (No. 4,717,325) designed a spinneret assembly with composite feed plates. Passages are aligned with the orifices in the first plate and feed core material. Each core material passage is surrounded by several feed passages for sheath material, forming core-sheath type composite fibers. [0004] Electrospinning, an efficient and versatile method that uses an electric field to manufacture polymer nanofibers, has attracted more and more attention. Electrospun fibers have large porosity and high surface area to volume ratio, making them excellent candidates for a number of applications as high efficient filters, biomedical materials, chemical sensors, protective materials, nano-composite materials, etc. [0005] However, there exist problems of fiber loss and unstable dispersion due to the nano-/micro-meter size of the electrospun fibers, and repellent force between nanofibers carried charges with same polarity. Electrospun nanofibers are often collected as randomly oriented structures in the form of nonwoven mats. It is difficult to manufacture continuous nanofiber yarns or filaments. [0006] Although tremendous progress has been made in the fabrication of aligned nanofibers by electrospinning, a major challenge remains in the search for an efficient means to manufacture continuous aligned filament yarns. Electrospun fibers can be aligned more or less parallel to each other when a drum rotating at high speed is used as the collector. Another method is to deposit nanofibers into water to eliminate the charges of nanofibers which are collected together, and yarns are drawn out. Others obtain aligned fiber yarns by linking and twisting the electrospun nanofibers deposited on the steel drum. [0007] Therefore, it is necessary to invent a more efficient method to prepare filament yarn of composite nanofibers. SUMMARY OF THE INVENTION [0008] The present invention is to provide device and method for preparing filament yarn of composite nanofibers which can manufacture filament yarn of composite nanofibers simply and efficiently. Technical Process [0009] Device for preparing filament yarn of composite nanofibers, comprising: pairs of electrospinning nozzles, filament guiding roller pair, frame, fixed sticks and base. Two columns of oppositely disposed pairs of electrospinning nozzles are fixed on frame. Each pair of electrospinning nozzles is in either same or different planes. The frame is connected to base by vertical fixed sticks. Filament guiding roller pair is located in the plane of frame with same distance away from two spouts of each electrospinning nozzles pair. The frame is set at an adjustable acute angle to the fixed sticks. The roller pair is at the end of pairs of electrospinning nozzles. Distance between two neighbouring electrospinning nozzles on the same column of frame is 2-50 cm. Distance between two spouts of oppositely disposed pair of electrospinning nozzles is 10-100 cm. Plane of frame is set at angle of 0-90° to fixed sticks. The detailed procedures for preparing filament yarn of composite nanofibers are as follows: [0000] 1) Polymer solutions are fed to pairs of electrospinning nozzles on frame. 2) High electrical voltages with opposite polarities are applied to two oppositely disposed pairs of electrospinning nozzles, respectively. 3) Nanofibers with opposite charges from each pair of electrospinning nozzles attract and strike together during the journey in the air, or the nanofibers attract and deposit on polymer fibrous carrier drawn down, forming composite nanofibers. The composite nanofibers are pulled and/or stretched, resulting in continuous filament yarn of composite nanofibers. 4) The filament yarn of composite nanofibers fabricated by the first pair of electrospinning nozzles are drawn down and used as a carrier to receive the nanofibers with opposite charge electrospun out from the second pair of nozzles. The coated filament yarn of composite nanofibers is then drawn down and/or stretched, forming two-layer filament yarn of composite nanofibers. 5) In turn, filament yarn of composite nanofibers fabricated by former pair of electrospinning nozzles are drawn down and used as a carrier to receive the nanofibers with opposite charge electrospun out from latter pair of nozzles. The coated filament yarn of composite nanofibers is then drawn down and/or stretched by filament guiding roller pair 2 , forming multi-layer filament yarn of composite nanofibers. [0010] High electrical voltages with opposite polarities applied to two oppositely disposed pairs of electrospinning nozzles are fixed at 3-200 kV, respectively. Polymer solutions fed to electrospinning nozzles are polymer solutions, additive-containing polymer solutions, or mixture of inorganic particles and polymer solutions. Polymers are any of polyolefin, halogen-substituted polyolefin, silicone, polyether, polyamide, polyester, polycarbonate, polyurethane, epoxy resin, polyacrylonitrile, polyacrylic acid, polyacrylates, polyphenyl ether, polyanhydride, poly(α-amine acid), polyphenyl sulfide ether, or mixtures of above two or more polymers, or any of cellulose, cellulose derivatives, dextran, silk fibroin, chitosan, chitosan derivatives, hyaluronic acid, hyaluronic acid derivatives, collagen, carrageenan, sodium alginate, calcium alginate, chondroitin sulphate, gelatin, agar, dextran, fibril, fibrinogen, keratin, casein, albumin, elastin, or their derivatives or mixtures of above two or more polymers, or any of bioabsorbable synthetic polymers, such as poly-L-lactic acid, poly-(D,L)-lactic acid, poly glycolic acid, polycaprolactone, polybutyrolactone, polyvalerolactone, poly-p-dioxane, polyanhydride, poly(α-amine acid), or copolymer synthesized from two or more monomers as follows: L-lactic acid, D, L-lactic acid, glycolic acid, 3-hydroxyl butanoic acid, 3-hydroxyl pentanoic acid, caprolactone, butyrolactone, valerolactone, amine acid, or mixtures of above two or more polymers. Inorganic particles are nano-antibacterial agents, catalysts, or carbon nanotubes. [0011] Additives are any of antibiotics, immunosuppressants, antibacterial agents, hormone, vitamin, amino acids, peptides, proteins, enzymes, growth factor, antibacterial drugs, dope, hemostasis agents, anodyne, anti-hyperpiesia agents and anti-tumour agents, or mixtures of above two or more agents. ADVANTAGES [0012] The present invention has following advantages: [0000] (1) The present invention utilizes a method for preparing filament yarn of composite nanofibers, where electrospinning nozzles oppositely disposed are electrically charged by high DC voltages with opposite polarities. Nanofibers electrospun from the two nozzles which carry charges with opposite polarities attract each other, strike together, and neutralize their charges. The present method shows a less dispersion and loss of nanofibers in the air. Furthermore, grounded metal collector used in conventional electrospinning method is unnecessary in the present invention. (2) In the present invention, frame is set at an adjustable acute angle to fixed sticks to avoid any slightly disturbed or unstable spinning jet. (3) The present invention can manufacture filament yarn of composite nanofibers simply and efficiently. (4) In the present invention, different polymer solutions or additive-containing polymer solutions can be fed to two spouts of electrospinning nozzles pair oppositely disposed respectively, resulting in the formation of composite filament yarn of multi-component nanofibers. (5) In the present invention, filament yarn of composite nanofibers with different composition and nano-structure can be produced by the use of multiple pairs of electrospinning nozzles. Thicker multi-layer filament yarn of composite nanofibers may exhibit good mechanical properties. (6) In the present invention, nanofibers from oppositely disposed electrospinning nozzles which carry charges with opposite polarities can deposit on polymer fiber carrier, and then drawn down by filament guiding roller pair set under frame with a less dispersion or loss of nanofibers. And, multi-layer filament yarn of composite nanofibers with polymer fiber carrier as core is produced having excellent mechanical properties. (7) The present invention can produce filament yarns of composite nanofibers including nano-particles as combined with electro-spraying technique. (8) The present invention can manufacture filament yarn of composite nanofibers having potential applications in tissue engineered scaffolds and textiles, etc. BRIEF DESCRIPTION OF THE DRAWINGS [0013] FIG. 1 is structure scheme of the present invention. [0014] FIG. 2 is principle scheme of the present invention. [0015] The two figures include pairs of electrospinning nozzles 1 , filament guiding roller pair 2 , frame 3 , fixed sticks 4 and base 5 . [0016] FIG. 3 is photograph of PLLA filament yarns of composite nanofibers. [0017] FIG. 4 is photograph of PLLA filament yarns of composite nanofibers. [0018] FIG. 5 is SEM image of PLLA filament yarns of composite nanofibers. [0019] FIG. 6 is SEM image of PU/PVDF filament yarn of composite nanofibers. [0020] FIG. 7 is SEM image of PAN filament yarn of composite nanofibers. [0021] FIG. 8 is SEM image of PVDF filament yarn of composite nanofibers. DETAILED DESCRIPTION OF THE INVENTION [0022] Device for preparing filament yarn of composite nanofibers, comprising: pairs of electrospinning nozzles 1 , filament guiding roller pair 2 , frame 3 , fixed sticks 4 and base 5 . Two columns of oppositely disposed pairs of electrospinning nozzles 1 are fixed on frame 3 . Each pair of electrospinning nozzles is in either same or different planes. The frame 3 is connected to base 5 by vertical fixed sticks 4 . Filament guiding roller pair 2 is located in the plane of frame 3 with same distance away from two spouts of each electrospinning nozzles pair. The roller pair 2 is at the end of pairs of electrospinning nozzles 1 . The frame 3 is set at an adjustable acute angle to the fixed sticks 4 . [0023] The detailed procedures for preparing filament yarn of composite nanofibers are as follows: [0000] 1) Polymer solutions are fed to pairs of electrospinning nozzles 1 on frame 3 . 2) High electrical voltages with opposite polarities are applied to two oppositely disposed pairs of electrospinning nozzles 1 , respectively. 3) Nanofibers with opposite charge from each pair of electrospinning nozzles attract and strike together during the journey in the air, forming composite nanofibers. The composite nanofibers are pulled and/or stretched, resulting in continuous filament yarn of composite nanofibers. 4) The filament yarn of composite nanofibers fabricated by the first pair of electrospinning nozzles are drawn down and used as a carrier to receive the nanofibers with opposite charge electrospun out from the second pair of nozzles. The coated filament yarn of composite nanofibers is then drawn down and/or stretched, forming two-layer filament yarn of composite nanofibers. 5) In turn, filament yarn of composite nanofibers fabricated by former pair of electrospinning nozzles are drawn down and used as a carrier to receive the nanofibers with opposite charge electrospun out from latter pair of nozzles. The coated filament yarn of composite nanofibers is then drawn down and/or stretched by filament guiding roller pair 2 , forming multi-layer filament yarn of composite nanofibers. [0024] The detailed procedures for preparing filament yarn of composite nanofibers can also be: 1) Polymer solutions are fed to pairs of electrospinning nozzles 1 on frame 3 . 2) High electrical voltages with opposite polarities are applied to two oppositely disposed pairs of electrospinning nozzles 1 , respectively. 3) Nanofibers with opposite charge from each pair of electrospinning nozzles 1 attract and deposit on polymer fibrous carrier drawn down, forming composite nanofibers. The composite nanofibers are pulled and/or stretched, resulting in continuous filament yarn of composite nanofibers. [0025] Distance between two neighbouring electrospinning nozzles 1 on the same column of frame 3 is 2-50 cm. Distance between two spouts of oppositely disposed pair of electrospinning nozzles 1 is 10-100 cm. Plane of frame 3 is set at angle of 0-90° to fixed sticks 4 . High electrical voltages with opposite polarities applied to two oppositely disposed pairs of electrospinning nozzles 1 are fixed at 5-200 kV, respectively. [0026] Polymer solutions fed to electrospinning nozzles are polymer solutions, additive-containing polymer solutions, or mixture of inorganic particles and polymer solutions. Polymers are any of polyolefin, halogen-substituted polyolefin, silicone, polyether, polyamide, polyester, polycarbonate, polyurethane, epoxy resin, polyacrylonitrile, polyacrylic acid, polyacrylates, polyphenyl ether, polyanhydride, poly(α-amine acid), polyphenyl sulfide ether, or mixtures of above two or more polymers, or any of cellulose, cellulose derivatives, dextran, silk fibroin, chitosan, chitosan derivatives, hyaluronic acid, hyaluronic acid derivatives, collagen, carrageenan, sodium alginate, calcium alginate, chondroitin sulphate, gelatin, agar, dextran, fibril, fibrinogen, keratin, casein, albumin, elastin, or their derivatives or mixtures of above two or more polymers, or any of bioabsorbable synthetic polymers, such as poly-L-lactic acid, poly-(D,L)-lactic acid, poly glycolic acid, polycaprolactone, polybutyrolactone, polyvalerolactone, poly-p-dioxane, polyanhydride, poly(α-amine acid), or copolymer synthesized from two or more monomers as follows: L-lactic acid, D, L-lactic acid, glycolic acid, 3-hydroxyl butanoic acid, 3-hydroxyl pentanoic acid, caprolactone, butyrolactone, valerolactone, amine acid, or mixtures of above two or more polymers. Inorganic particles are nano-antibacterial agents, catalysts, or carbon nanotubes. Additives are any of antibiotics, immunosuppressants, antibacterial agents, hormone, vitamin, amino acids, peptides, proteins, enzymes, growth factor, antibacterial drugs, dope, hemostasis agents, anodyne, anti-hyperpiesia agents and anti-tumour agents, or mixtures of above two or more agents. [0027] The present invention can manufacture filament yarn of composite nanofibers having potential applications in regeneration medicine and textiles, etc. EXAMPLE 1 [0028] A device for electrospinning is used comprising frame 3 having three pairs of electrospinning nozzles 1 in two columns, filament guiding roller pair 2 set at the end of pairs of electrospinning nozzles. The frame 3 was set at angle of 90° to fixed sticks 4 . [0029] 10 g poly-L-lactic acid (PLLA, Mη=100,000 g/mol) was dissolved in a mixed solvent of 50 ml acetone and 50 ml N,N-dimethyl formamide, and the prepared solution was fed to one column of electrospinning nozzles containing 3 spinnerets. 15 g poly-lactide-co-glycolide (Poly-LA-co-GA, PLGA, weight ratio of LA:GA=50:50, Mη=100,000 g/mol) was dissolved in a mixed solvent of 50 ml acetone and 50 ml N,N-dimethyl formamide, and the prepared solution was fed to the other column of electrospinning nozzles containing 3 spinnerets. Distance between two neighbouring electrospinning nozzles on the same column of frame 3 is 15 cm, and distance between two tips of oppositely disposed pair of electrospinning nozzles is 40 cm. Plane of frame 3 is set at angle of 90° to fixed sticks 4 . High DC voltages of +20 kV were applied to two columns of oppositely disposed electrospinning nozzles with inner diameter of 0.5 mm, respectively. Nanofibers exiting from the electrospinning nozzles were induced and drawn out by filament guiding roller pair which is set at the end of pairs of electrospinning nozzles on the plane of the frame. The drawing speed of filament guiding roller pair was 8 cm/s. And, three-layer filament yarn of PLLA/PLGA composite nanofibers is obtained. EXAMPLE 2 [0030] A device for electrospinning is used comprising frame 3 having four pairs of electrospinning nozzles 1 in two columns, filament guiding roller pair 2 set at the end of pairs of electrospinning nozzles. The frame 3 was set at angle of 90° to fixed sticks 4 . [0031] 10 g poly-L-lactic acid (PLLA, Mq=100,000 g/mol) was dissolved in a mixed solvent of 50 ml acetone and 50 ml N,N-dimethyl formamide, and the prepared solution was fed to one column of electrospinning nozzles containing 4 spinnerets. 10 g polycaprolactone (PCL, Mw=90,000 g/mol) was dissolved in 100 ml N, N-dimethyl formamide, and the prepared solution was fed to the other column of electrospinning nozzles containing 4 spinnerets. Distance between two neighbouring electrospinning nozzles on the same column of frame 3 is 15 cm, and distance between two tips of oppositely disposed pair of electrospinning nozzles is 40 cm. Plane of frame 3 is set at angle of 90° to fixed sticks 4 . High DC voltages of ±20 kV were applied to two columns of oppositely disposed electrospinning nozzles with inner diameter of 0.5 mm, respectively. The drawing speed of filament guiding roller pair 2 was 8 cm/s. Nanofibers exiting from the electrospinning nozzles were induced and drawn out by filament guiding roller pair 2 which is set at the end of pairs of electrospinning nozzles on the plane of the frame 3 . And, multi-layer filament yarn of PLLA/PCL composite nanofibers is obtained. EXAMPLE 3 [0032] A device for electrospinning is used comprising frame 3 having three pairs of electrospinning nozzles 1 in two columns, filament guiding roller pair 2 set at the end of pairs of electrospinning nozzles. The frame 3 was set at angle of 90° to fixed sticks 4 . [0033] 10 g poly-L-lactic acid (PLLA, Mη=100,000 g/mol) was dissolved in a mixed solvent of 50 ml acetone and 50 ml N,N-dimethyl formamide, and the prepared solution was fed to one column of electrospinning nozzles containing 3 spinnerets of which inner diameter is 0.8 mm. 35 g zein (Mw=35,000 g/mol) was dissolved in 100 ml aqueous ethanol solution with ethanol/water volume ratio of 80/20, and the prepared solution was fed to the other column of electrospinning nozzles containing 3 spinnerets of which inner diameter is 1.2 mm. Distance between two neighbouring electrospinning nozzles on the same column of frame is 15 cm, and distance between two tips of oppositely disposed pair of electrospinning nozzles is 40 cm. Plane of frame 3 is set at angle of 90° to fixed sticks 4 . High DC voltages of +25 kV were applied to two columns of oppositely disposed electrospinning nozzles, respectively. The drawing speed of filament guiding roller pair 2 was 8 cm/s. Nanofibers exiting from the electrospinning nozzles were induced and drawn out by filament guiding roller pair 2 which is set at the end of pairs of electrospinning nozzles on the plane of the frame 3 . And, three-layer filament yarn of PLLA/zein composite nanofibers is obtained. EXAMPLE 4 [0034] A device for electrospinning is used comprising frame 3 having four pairs of electrospinning nozzles 1 in two columns, filament guiding roller pair 2 set at the end of pairs of electrospinning nozzles. The frame 3 was set at angle of 90° to fixed sticks 4 . [0035] 10 g polyacrylonitrile (PAN, Mw=130,000 g/mol) was dissolved in 100 ml N, N-dimethyl formamide, and the prepared solution was fed to one column of electrospinning nozzles containing 4 spinnerets. 10 g polyphenyl ether sulphone (PES, melt flow rate 3.9 g/10 min, 320° C.) was dissolved in 100 ml dimethyl sulphone, and the prepared solution was fed to the other column of electrospinning nozzles containing 4 spinnerets. Distance between two neighbouring electrospinning nozzles on the same column of frame is 15 cm, and distance between two tips of oppositely disposed pair of electrospinning nozzles is 40 cm. Plane of frame 3 is set at angle of 90° to fixed sticks 4 . High DC voltages of ±20 kV were applied to two columns of oppositely disposed electrospinning nozzles with inner diameter of 0.5 mm, respectively. Nanofibers exiting from the electrospinning nozzles were induced and drawn out by filament guiding roller pair 2 which is set at the end of pairs of electrospinning nozzles on the plane of the frame 3 . The drawing speed of filament guiding roller pair 2 was 8 cm/s. And, multi-layer filament yarn of PAN/PPES composite nanofibers is obtained. EXAMPLE 5 [0036] A device for electrospinning is used comprising frame 3 having two pairs of electrospinning nozzles 1 in two columns, filament guiding roller pair 2 set at the end of pairs of electrospinning nozzles. The frame 3 was set at angle of 0° to fixed sticks 4 . [0037] 10 g poly-L-lactic acid (PLLA, M11=100,000 g/mol) was dissolved in a mixed solvent of 50 ml acetone and 50 ml N, N-dimethyl formamide. 15 g poly-lactide-co-glycolide (Poly-LA-co-GA, PLGA, weight ratio of LA:GA=50:50, Mη=100,000 g/mol) was dissolved in a mixed solvent of 50 ml acetone and 50 ml N, N-dimethyl formamide. 15 g polyurethane (PU) was dissolved in 100 ml N, N-dimethyl formamide. 10 g polycaprolactone (PCL, Mw=90,000 g/mol) was dissolved in 100 ml N, N-dimethyl formamide. After complete dissolution, solutions were fed to two columns of oppositely disposed 4 electrospinning nozzles, respectively. Distance between two neighbouring electrospinning nozzles on the same column of frame is 15 cm, and distance between two tips of oppositely disposed pair of electrospinning nozzles is 40 cm. Plane of frame 3 is set at angle of 0° to fixed sticks 4 . High DC voltages of ±20 kV were applied to two columns of oppositely disposed electrospinning nozzles with inner diameter of 0.8 mm, respectively. Nanofibers exiting from the electrospinning nozzles were induced and drawn out by filament guiding roller pair 2 which is set at the end of pairs of electrospinning nozzles on the plane of the frame 3 . The drawing speed of filament guiding roller pair 2 was 5 cm/s. And, filament yarn of PLLA/PLGA/PU/PCL composite nanofibers is obtained. EXAMPLE 6 [0038] A device for electrospinning is used comprising frame 3 having three pairs of electrospinning nozzles 1 in two columns, filament guiding roller pair 2 set at the end of pairs of electrospinning nozzles. The frame 3 was set at angle of 0° to fixed sticks 4 . [0039] 1 g hyaluronic acid (HA, Mw=100,000 g/mol) was dissolved in 100 ml distilled water. 0.5 g chitosan was dissolved in 100 ml 0.1 mol/L acetic acid solution. 10 g poly-L-lactic acid (PLLA, Mη=100,000 g/mol) was dissolved in a mixed solvent of 50 ml acetone and 50 ml N, N-dimethyl formamide. 15 g poly-lactide-co-glycolide (Poly-LA-co-GA, PLGA, weight ratio of LA:GA=50:50, Mη=100,000 g/mol) was dissolved in a mixed solvent of 50 ml acetone and 50 ml N, N-dimethyl formamide. 15 g polyurethane (PU) was dissolved in 100 ml N, N-dimethyl formamide. 10 g polycaprolactone (PCL, Mw=90,000 g/mol) was dissolved in 100 ml N, N-dimethyl formamide. After complete dissolution, solutions were fed to two columns of oppositely disposed 6 electrospinning nozzles, respectively. Distance between two neighbouring electrospinning nozzles on the same column of frame is 10 cm, and distance between two tips of oppositely disposed pair of electrospinning nozzles is 30 cm. Plane of frame 3 is set at angle of 0° to fixed sticks 4 . High DC voltages of ±20 kV were applied to two columns of oppositely disposed electrospinning nozzles with inner diameter of 0.8 mm, respectively. Nanofibers exiting from the electrospinning nozzles were induced and drawn out by filament guiding roller pair 2 which is set at the end of pairs of electrospinning nozzles on the plane of the frame 3 . The drawing speed of filament guiding roller pair 2 was 5 cm/s. And, filament yarn of HA/chitosan/PLLA/PLGA/PU/PCL composite nanofibers is obtained. EXAMPLE 7 [0040] A device for electrospinning is used comprising frame 3 having three pairs of electrospinning nozzles 1 in two columns, filament guiding roller pair 2 set at the end of pairs of electrospinning nozzles. The frame 3 was set at angle of 0° to fixed sticks 4 . [0041] 1 g hyaluronic acid (HA, Mw=100,000 g/mol) was dissolved in 100 ml distilled water, and the prepared solution was fed to one column of electrospinning nozzles containing 3 spinnerets. 10 g poly-L-lactic acid (PLLA, Mη=100,000 g/mol) was dissolved in a mixed solvent of 50 ml acetone and 50 ml N, N-dimethyl formamide, and the prepared solution was fed to the other column of electrospinning nozzles containing 3 spinnerets. Distance between two neighbouring electrospinning nozzles on the same column of frame is 10 cm, and distance between two tips of oppositely disposed pair of electrospinning nozzles is 30 cm. Plane of frame 3 is set at angle of 0° to fixed sticks 4 . High DC voltages of ±20 kV were applied to two columns of oppositely disposed electrospinning nozzles with inner diameter of 0.8 mm, respectively. Nanofibers exiting from the electrospinning nozzles were induced and drawn out by filament guiding roller pair 2 which is set at the end of pairs of electrospinning nozzles on the plane of the frame 3 . The drawing speed of filament guiding roller pair 2 was 5 cm/s. And, filament yarn of HA/PLLA composite nanofibers is obtained. EXAMPLE 8 [0042] A device for electrospinning is used comprising frame 3 having three pairs of electrospinning nozzles 1 in two columns, filament guiding roller pair 2 set at the end of pairs of electrospinning nozzles. The frame 3 was set at angle of 0° to fixed sticks 4 . [0043] 1 g hyaluronic acid (HA, Mw=100,000 g/mol) was dissolved in 100 ml distilled water, and 0.2 g brophenol was added into the solution. After complete dissolution of brophenol, the solution was fed to one column of electrospinning nozzles containing 3 spinnerets. 10 g poly-L-lactic acid (PLLA, Mη=100,000 g/mol) was dissolved in a mixed solvent consisting of 50 ml acetone and 50 ml N, N-dimethyl formamide, and the prepared solution was fed to the other column of electrospinning nozzles containing 3 spinnerets. Distance between two neighbouring electrospinning nozzles on the same column of frame is 10 cm, and distance between two tips of oppositely disposed pair of electrospinning nozzles is 30 cm. Plane of frame 3 is set at angle of 0° to fixed sticks 4 . High DC voltages of ±20 kV were applied to two columns of oppositely disposed electrospinning nozzles with inner diameter of 0.8 mm, respectively. Nanofibers exiting from the electrospinning nozzles were induced and drawn out by filament guiding roller pair 2 which is set at the end of pairs of electrospinning nozzles on the plane of the frame 3 . The drawing speed of filament guiding roller pair 2 was 5 cm/s. And, filament yarn of HA/brophenol/PLLA composite nanofibers is obtained. EXAMPLE 9 [0044] A device for electrospinning is used comprising frame 3 having three pairs of electrospinning nozzles 1 in two columns, filament guiding roller pair 2 set at the end of pairs of electrospinning nozzles. The frame 3 was set at angle of 0° to fixed sticks 4 . [0045] 10 g polyacrylonitrile (PAN) was dissolved in 100 ml N, N-dimethyl formamide, and the prepared solution was fed to one column of electrospinning nozzles containing 3 spinnerets. 15 g polyurethane (PU) was dissolved in 100 ml N, N-dimethyl formamide, and the prepared solution was fed to the other column of electrospinning nozzles containing 3 spinnerets. Distance between two neighbouring electrospinning nozzles on the same column of frame is 10 cm, and distance between two tips of oppositely disposed pair of electrospinning nozzles is 30 cm. Plane of frame 3 is set at angle of 0° to fixed sticks 4 . High DC voltages of ±20 kV were applied to two columns of oppositely disposed electrospinning nozzles with inner diameter of 0.8 mm, respectively. Drawing speed of filament guiding roller pair is 5 cm/s. Nanofibers from the oppositely disposed electrospinning nozzles which carry charges with opposite polarities deposited on polyester fibers and then drawn out by filament guiding roller pair 2 set under frame. Multi-layer filament yarns of composite nanofibers whose core is polyester fibers with shell of composite PAN/PU nanofibers were drawn out and collected by the filament guiding roller pair. EXAMPLE 10 [0046] A device for electrospinning is used comprising frame 3 having four pairs of electrospinning nozzles 1 in two columns, filament guiding roller pair 2 set at the end of pairs of electrospinning nozzles. The frame 3 was set at angle of 45° to fixed sticks 4 . [0047] 10 g polyurethane (PU) was dissolved in 100 ml N, N-dimethyl formamide, and the prepared solution was fed to one column of electrospinning nozzles containing 4 spinnerets. 10 g polycaprolactone was dissolved in 100 ml N, N-dimethyl formamide, and the prepared solution was fed to the other column of electrospinning nozzles containing 4 spinnerets. Distance between two neighbouring electrospinning nozzles on the same column of frame is 10 cm, and distance between two tips of oppositely disposed pair of electrospinning nozzles is 30 cm. Plane of frame 3 is set at angle of 45° to fixed sticks 4 . High DC voltages of +15 kV were applied to two columns of oppositely disposed electrospinning nozzles with inner diameter of 1.2 mm, respectively. Drawing speed of filament guiding roller pair 2 is 5 cm/s. Nanofibers exiting from the electrospinning nozzles were induced and drawn out by the filament guiding roller pair, collecting as continuous multi-layer filament yarn of PU/PCL composite nanofibers. EXAMPLE 11 [0048] A device for electrospinning is used comprising frame 3 having two pairs of electrospinning nozzles 1 in two columns, filament guiding roller pair 2 set at the end of pairs of electrospinning nozzles. The frame 3 was set at angle of 0° to fixed sticks 4 . [0049] 10 g poly-L-lactic acid (PLLA, Mη=100,000 g/mol) was dissolved in a mixed solvent of 100 ml acetone and 50 ml N,N-dimethyl formamide, and the prepared solution was fed to the two columns of oppositely disposed 4 electrospinning nozzles. Distance between two neighbouring electrospinning nozzles on the same column of frame is 15 cm, and distance between two tips of oppositely disposed pair of electrospinning nozzles is 40 cm. Plane of frame 3 is set at angle of 0° to fixed sticks 4 . High DC voltages of ±20 kV were applied to two columns of oppositely disposed electrospinning nozzles with inner diameter of 1.2 mm, respectively. The drawing speed of filament guiding roller pair 2 was 5 cm/s. Nanofibers exiting from the electrospinning nozzles were induced and drawn out by filament guiding roller pair 2 which is set at the end of pairs of electrospinning nozzles on the plane of the frame 3 . And, filament yarn of PLLA composite nanofibers is obtained. EXAMPLE 12 [0050] A device for electrospinning is used comprising frame 3 having two pairs of electrospinning nozzles 1 in two columns, filament guiding roller pair 2 set at the end of pairs of electrospinning nozzles. The frame 3 was set at angle of 0° to fixed sticks 4 . [0051] 10 g polycaprolactone (PCL) was dissolved in 100 ml N, N-dimethyl formamide, and the prepared solution was fed to the first pair of electrospinning nozzles. 15 g poly-lactide-co-glycolide (Poly-LA-co-GA, PLGA, weight ratio of LA:GA=50:50, Mη=100,000 g/mol) was dissolved in a mixed solvent of 50 ml acetone and 50 ml N,N-dimethyl formamide, 0.3 g brophenol was then added into the solution. After complete dissolution of brophenol, the solution was fed to the second pair of electrospinning nozzles. Distance between two neighbouring electrospinning nozzles on the same column of frame is 15 cm, and distance between two tips of oppositely disposed pair of electrospinning nozzles is 30 cm. Plane of frame 3 is set at angle of 0° to fixed sticks 4 . High DC voltages of +10 kV were applied to two columns of oppositely disposed electrospinning nozzles with inner diameter of 0.8 mm, respectively. Nanofibers exiting from the electrospinning nozzles were induced and drawn out by filament guiding roller pair 2 which is set at the end of pairs of electrospinning nozzles on the plane of the frame 3 . The drawing speed of filament guiding roller pair 2 was 5 cm/s. And, two-layer filament yarn of PCL/PLGA composite nanofibers is obtained. EXAMPLE 13 [0052] A device for electrospinning is used comprising frame 3 having ten pairs of electrospinning nozzles 1 in two columns, filament guiding roller pair 2 set at the end of pairs of electrospinning nozzles. The frame 3 was set at angle of 30° to fixed sticks 4 . [0053] 50 g poly-L-lactic acid (PLLA, Mq=150,000 g/mol) was dissolved in a mixed solvent of 250 ml acetone and 250 ml N,N-dimethyl formamide, and the prepared solution was fed to one column of electrospinning nozzles containing 10 spinnerets. 5 g hyaluronic acid (HA, Mw=1,000,000 g/mol) was dissolved in 500 ml distilled water, and the prepared solution was fed to the other column of electrospinning nozzles containing 10 spinnerets. Distance between two neighbouring electrospinning nozzles on the same column of frame is 10 cm, and distance between two tips of oppositely disposed pair of electrospinning nozzles is 30 cm. Planes of frame and fixed sticks were set at an angle of 30°. High DC voltages of ±50 kV were applied to two columns of oppositely disposed electrospinning nozzles with inner diameter of 0.8 mm, respectively. Drawing speed of filament guiding roller pair 2 is 5 cm/s. Nanofibers exiting from the electrospinning nozzles were induced and drawn out by the filament guiding roller pair, collecting as continuous filament yarn of PLLA/HA composite nanofibers with diameter of ca. 150 micros. EXAMPLE 14 [0054] A device for electrospinning is used comprising frame 3 having three pairs of electrospinning nozzles 1 in two columns, filament guiding roller pair 2 set at the end of pairs of electrospinning nozzles. The frame 3 was set at angle of 30° to fixed sticks 4 . [0055] 0.5 g chitosan was dissolved in 100 ml 0.1 mol/L acetic acid solution, and the prepared solution was fed to one column of electrospinning nozzles containing 3 spinnerets. 10 g polycaprolactone (PCL) was dissolved in 100 ml N, N-dimethyl formamide, and the prepared solution was fed to the other column of electrospinning nozzles containing 3 spinnerets. Distance between two neighbouring electrospinning nozzles on the same column of frame is 10 cm, and distance between two tips of oppositely disposed pair of electrospinning nozzles is 20 cm. Planes of frame and fixed sticks were set at an angle of 30°. High DC voltages of +20 kV were applied to two columns of oppositely disposed electrospinning nozzles with inner diameter of 0.6 mm, respectively. Nanofibers exiting from the electrospinning nozzles were induced and drawn out by filament guiding roller pair 2 which is set at the end of pairs of electrospinning nozzles on the plane of the frame 3 . The drawing speed of filament guiding roller pair 2 was 5 cm/s. And, filament yarn of chitosan/PCL composite nanofibers is obtained. EXAMPLE 15 [0056] A device for electrospinning is used comprising frame 3 having four pairs of electrospinning nozzles 1 in two columns, filament guiding roller pair 2 set at the end of pairs of electrospinning nozzles. The frame 3 was set at angle of 90° to fixed sticks 4 . [0057] 10 g polycarbonate (PC, Mw=100,000 g/mol) was dissolved in 100 ml N, N-dimethyl formamide, and the prepared solution was fed to one column of electrospinning nozzles containing 4 spinnerets. 10 g polyphenyl ether sulphone (PES, melt flow rate 3.9 g/10 min, 320° C.) was dissolved in 100 ml dimethyl sulphone, and the prepared solution was fed to the other column of electrospinning nozzles containing 4 spinnerets. Distance between two neighbouring electrospinning nozzles on the same column of frame is 15 cm, and distance between two tips of oppositely disposed pair of electrospinning nozzles is 40 cm. Plane of frame 3 is set at angle of 90° to fixed sticks 4 . High DC voltages of +20 kV were applied to two columns of oppositely disposed electrospinning nozzles with inner diameter of 0.5 mm, respectively. Nanofibers exiting from the electrospinning nozzles were induced and drawn out by filament guiding roller pair 2 which is set at the end of pairs of electrospinning nozzles on the plane of the frame 3 . The drawing speed of filament guiding roller pair 2 was 8 cm/s. And, multi-layer filament yarn of PC/PPES composite nanofibers is obtained. EXAMPLE 16 [0058] A device for electrospinning is used comprising frame 3 having four pairs of electrospinning nozzles 1 in two columns, filament guiding roller pair 2 set at the end of pairs of electrospinning nozzles. The frame 3 was set at angle of 30° to fixed sticks 4 . [0059] 10 g polyacrylonitrile (PAN, Mw=130,000 g/mol) was dissolved in 100 ml N, N-dimethyl fommamide, and 0.1 g single wall carbon nanotubes were added into the solution. After completely homogeneous dispersion of the nanotubes by ultrasonic vibration, the solution was fed to one column of electrospinning nozzles containing 4 spinnerets. 10 g polyphenyl ether sulphone (PES, melt flow rate 3.9 g/10 min, 320° C.) was dissolved in 100 ml dimethyl sulphone, and the prepared solution was fed to the other column of electrospinning nozzles containing 4 spinnerets. Distance between two neighbouring electrospinning nozzles on the same column of frame is 15 cm, and distance between two tips of oppositely disposed pair of electrospinning nozzles is 40 cm. Planes of frame and fixed sticks were set at an angle of 30°. High DC voltages of ±20 kV were applied to two columns of oppositely disposed electrospinning nozzles with inner diameter of 0.5 mm, respectively. Drawing speed of the filament guiding roller pair is 8 cm/s. Nanofibers exiting from the electrospinning nozzles were induced and drawn out by the filament guiding roller pair, collecting as continuous filament yarn of single wall carbon nanotubes and PC/PPES composite nanofibers. EXAMPLE 17 [0060] A device for electrospinning is used comprising frame 3 having three pairs of electrospinning nozzles 1 in two columns, filament guiding roller pair 2 set at the end of pairs of electrospinning nozzles. The frame 3 was set at angle of 0° to fixed sticks 4 . [0061] 1 g hyaluronic acid (HA, Mw=100,000 gμmol) was dissolved in 100 ml distilled water, and 10 mg bone morphogenetic protein were added into the solution. After completely dissolution of the bone morphogenetic protein, the solution was fed to one column of electrospinning nozzles containing 3 spinnerets. 10 g poly-L-lactic acid (PLLA, Mη=100,000 g/mol) was dissolved in a mixed solvent of 50 ml acetone and 50 ml N,N-dimethyl formamide, and the prepared solution was fed to the other column of electrospinning nozzles containing 3 spinnerets. Distance between two neighbouring electrospinning nozzles on the same column of frame is 10 cm, and distance between two tips of oppositely disposed pair of electrospinning nozzles is 30 cm. Plane of frame 3 is set at angle of 0° to fixed sticks 4 . High DC voltages of ±20 kV were applied to two columns of oppositely disposed electrospinning nozzles with inner diameter of 0.8 mm, respectively. Nanofibers exiting from the electrospinning nozzles were induced and drawn out by filament guiding roller pair 2 which is set at the end of pairs of electrospinning nozzles on the plane of the frame 3 . The drawing speed of filament guiding roller pair 2 was 5 cm/s. And, filament yarn of HA/PLLA composite nanofibers is obtained. EXAMPLE 18 [0062] A device for electrospinning is used comprising frame 3 having two pairs of electrospinning nozzles 1 in two columns, filament guiding roller pair 2 set at the end of pairs of electrospinning nozzles. The frame 3 was set at angle of 0° to fixed sticks 4 . [0063] 20 g poly-L-lactic acid (PLLA, Mη=100,000 g/mol) was dissolved in a mixed solvent of 100 ml acetone and 50 ml N,N-dimethyl formamide, and 1 g β-tricalcium phosphate (β-TCP) nano-particles with diameters of ca. 300 nm were added into the solution. After completely homogeneous dispersion of the nano-particles by ultrasonic vibration, the solution was fed to two columns of oppositely disposed 4 electrospinning nozzles. Distance between two neighbouring electrospinning nozzles on the same column of frame is 15 cm, and distance between two tips of oppositely disposed pair of electrospinning nozzles is 40 cm. Plane of frame 3 is set at angle of 0° to fixed sticks 4 . High DC voltages of ±50 kV were applied to two columns of oppositely disposed electrospinning nozzles with inner diameter of 1.2 mm, respectively. Nanofibers exiting from the electrospinning nozzles were induced and drawn out by filament guiding roller pair 2 which is set at the end of pairs of electrospinning nozzles on the plane of the frame 3 . The drawing speed of filament guiding roller pair 2 was 5 cm/s. And, filament yarn of PLLA/β-TCP composite nanofibers is obtained. EXAMPLE 19 [0064] A device for electrospinning is used comprising frame 3 having twenty-five pairs of electrospinning nozzles 1 in two columns, filament guiding roller pair 2 set at the end of pairs of electrospinning nozzles. The frame 3 was set at angle of 0° to fixed sticks 4 . [0065] 100 g poly-L-lactic acid (PLLA, Mη=150,000 g/mol) was dissolved in a mixed solvent of 500 ml acetone and 500 ml N,N-dimethyl formamide, and the prepared solution was fed to one column of electrospinning nozzles containing 25 spinnerets. 10 g hyaluronic acid (HA, Mw—1,000,000 g/mol) was dissolved in 1000 ml distilled water, and the prepared solution was fed to the other column of electrospinning nozzles containing 25 spinnerets. Distance between two neighbouring electrospinning nozzles on the same column of frame is 2 cm, and distance between two tips of oppositely disposed pair of electrospinning nozzles is 40 cm. Plane of frame 3 is set parallel to fixed sticks 4 . High DC voltages of ±120 kV were applied to two columns of oppositely disposed electrospinning nozzles with inner diameter of 1.2 mm, respectively. Drawing speed of the filament guiding roller pair 2 is 10 cm/s. Nanofibers exiting from the electrospinning nozzles were induced and drawn out by the filament guiding roller pair, collecting as continuous filament yarn of PLLA/HA composite nanofibers with diameter of ca. 200 micros. EXAMPLE 20 [0066] A device for electrospinning is used comprising frame 3 having ten pairs of electrospinning nozzles 1 in two columns, filament guiding roller pair 2 set at the end of pairs of electrospinning nozzles. The frame 3 was set at angle of 0° to fixed sticks 4 . [0067] 50 g poly-L-lactic acid (PLLA, M=150,000 g/mol) was dissolved in a mixed solvent of 250 ml acetone and 250 ml N,N-dimethyl formamide, and the prepared solution was fed to two columns of oppositely disposed 20 electrospinning nozzles. Distance between two neighbouring electrospinning nozzles on the same column of frame is 8 cm, and distance between two tips of oppositely disposed pair of electrospinning nozzles is 40 cm. Plane of frame 3 is set parallel to fixed sticks 4 . High DC voltages of +80 kV were applied to two columns of oppositely disposed electrospinning nozzles with inner diameter of 1.2 mm, respectively. Drawing speed of filament guiding roller pair 2 is 5 cm/s. Nanofibers exiting from the electrospinning nozzles were induced and drawn out by the filament guiding roller pair, collecting as continuous PLLA composite nanofiber yarns with diameter of ca. 100 micros. EXAMPLE 21 [0068] A device for electrospinning is used comprising frame 3 having two pairs of electrospinning nozzles 1 in two columns, filament guiding roller pair 2 set at the end of pairs of electrospinning nozzles. The frame 3 was set at angle of 0° to fixed sticks 4 . [0069] 10 g poly-L-lactic acid (PLLA, M11=150,000 g/mol) was dissolved in a mixed solvent of 50 ml acetone and 50 ml N,N-dimethyl formamide, and the prepared solution was fed to one column of electrospinning nozzles containing 2 spinnerets. 1.5 g collagen was dissolved in 30 ml hexafluoro-2-propanol (HFIP), and the prepared solution was fed to the other column of electrospinning nozzles containing 2 spinnerets. Distance between two neighbouring electrospinning nozzles on the same column of frame is 10 cm, and distance between two tips of oppositely disposed pair of electrospinning nozzles is 30 cm. Plane of frame 3 is set parallel to fixed sticks 4 . High DC voltages of ±30 kV were applied to two columns of oppositely disposed electrospinning nozzles with inner diameter of 1.2 mm, respectively. The drawing speed of filament guiding roller pair 2 was 3 cm/s. Nanofibers exiting from the electrospinning nozzles were induced and drawn out by filament guiding roller pair 2 which is set at the end of pairs of electrospinning nozzles on the plane of the frame 3 . And, filament yarn of PLLA/collagen composite nanofibers is obtained. EXAMPLE 22 [0070] A device for electrospinning is used comprising frame 3 having two pairs of electrospinning nozzles 1 in two columns, filament guiding roller pair 2 set at the end of pairs of electrospinning nozzles. The frame 3 was set at angle of 30° to fixed sticks 4 . [0071] 10 g poly (vinylidenefluoride) (PVDF) was dissolved in a mixed solvent of 50 ml acetone and 50 ml N, N-dimethyl formamide, and the prepared solution was fed to two columns of oppositely disposed 4 electrospinning nozzles. Distance between two neighbouring electrospinning nozzles on the same column of frame is 15 cm, and distance between two tips of oppositely disposed pair of electrospinning nozzles is 40 cm. Plane of frame 3 is set at angle of 30° to fixed sticks 4 . High DC voltages of ±30 kV were applied to two columns of oppositely disposed electrospinning nozzles with inner diameter of 1.2 mm, respectively. The drawing speed of filament guiding roller pair 2 was 3 cm/s. Nanofibers exiting from the electrospinning nozzles were induced and drawn out by filament guiding roller pair 2 which is set at the end of pairs of electrospinning nozzles on the plane of the frame 3 . And, filament yarn of PVDF composite nanofibers is obtained. EXAMPLE 23 [0072] A device for electrospinning is used comprising frame 3 having two pairs of electrospinning nozzles 1 in two columns, filament guiding roller pair 2 set at the end of pairs of electrospinning nozzles. The frame 3 was set at angle of 0° to fixed sticks 4 . [0073] 10 g poly (vinylidenefluoride) (PVDF) was dissolved in a mixed solvent of 50 ml acetone and 50 ml N, N-dimethyl formamide, and the prepared solution was fed to one column of electrospinning nozzles containing 2 spinnerets. 15 g polyurethane (PU) was dissolved in 100 ml N, N-dimethyl formamide, and the prepared solution was fed to the other column of electrospinning nozzles containing 2 spinnerets. Distance between two neighbouring electrospinning nozzles on the same column of frame is 10 cm, and distance between two tips of oppositely disposed pair of electrospinning nozzles is 30 cm. Plane of frame 3 is set parallel to fixed sticks 4 . High DC voltages of ±20 kV were applied to two columns of oppositely disposed electrospinning nozzles with inner diameter of 1.2 mm, respectively. The drawing speed of filament guiding roller pair 2 was 3 cm/s. Nanofibers exiting from the electrospinning nozzles were induced and drawn out by filament guiding roller pair 2 which is set at the end of pairs of electrospinning nozzles on the plane of the frame 3 . And, filament yarn of PVDF/PU composite nanofibers is obtained. EXAMPLE 24 [0074] A device for electrospinning is used comprising frame 3 having two pairs of electrospinning nozzles 1 in two columns, filament guiding roller pair 2 set at the end of pairs of electrospinning nozzles. The frame 3 was set at angle of 0° to fixed sticks 4 . [0075] 10 g poly-L-lactic acid (PLLA, M11=150,000 g/mol) was dissolved in a mixed solvent of 50 ml acetone and 50 ml N,N-dimethyl formamide, and the prepared solution was fed to one column of electrospinning nozzles containing 2 spinnerets. 10 g poly (vinyl pyrrolidone) (PVP K30, BASF) was dissolved in 50 ml acetone, and the prepared solution was fed to the other column of electrospinning nozzles containing 2 spinnerets. Distance between two neighbouring electrospinning nozzles on the same column of frame is 10 cm, and distance between two tips of oppositely disposed pair of electrospinning nozzles is 30 cm. Plane of frame 3 is set parallel to fixed sticks 4 . High DC voltages of ±20 kV were applied to two columns of oppositely disposed electrospinning nozzles with inner diameter of 1.2 mm, respectively. The drawing speed of filament guiding roller pair 2 was 3 cm/s. Nanofibers exiting from the electrospinning nozzles were induced and drawn out by filament guiding roller pair 2 which is set at the end of pairs of electrospinning nozzles on the plane of the frame 3 . And, filament yarn of PLLA/PVP composite nanofibers is obtained. EXAMPLE 25 [0076] A device for electrospinning is used comprising frame 3 having three pairs of electrospinning nozzles 1 in two columns, filament guiding roller pair 2 set at the end of pairs of electrospinning nozzles. The frame 3 was set at angle of 0° to fixed sticks 4 . [0077] 10 g poly-L-lactic acid (PLLA, Mη=100,000 g/mol) was dissolved in a mixed solvent of 50 ml acetone and 50 ml N, N-dimethyl formamide. 15 g poly-lactide-co-glycolide (Poly-LA-co-GA, PLGA, weight ratio of LA:GA=50:50, Mη=100,000 g/mol) was dissolved in a mixed solvent of 50 ml acetone and 50 ml N, N-dimethyl formamide. 1 g hyaluronic acid (HA, Mw=100,000 g/mol) was dissolved in 100 ml distilled water. 0.3 g chitosan was dissolved in 100 ml 0.1 mol/L acetic acid solution. 1.5 g collagen was dissolved in hexafluoro-2-propanol (HFIP). 10 g polycaprolactone (PCL, Mw=90,000 g/mol) was dissolved in 100 ml N, N-dimethyl formamide. After complete dissolution, solutions were fed to two columns of oppositely disposed 6 electrospinning nozzles, respectively. Distance between two neighbouring electrospinning nozzles on the same column of frame is 10 cm, and distance between two tips of oppositely disposed pair of electrospinning nozzles is 30 cm. Plane of frame 3 is set parallel to fixed sticks 4 . High DC voltages of +15 kV were applied to two columns of oppositely disposed electrospinning nozzles with inner diameter of 0.8 mm, respectively. Filament yarn of composite nanofibers fabricated by former pair of electrospinning nozzles are drawn out and subsequently wrapped around composite nanofibers from latter pair of two oppositely charged electrospinning nozzles. The nanofibers are then drawn out and/or stretched by filament guiding roller pair, forming filament yarn of composite nanofibers.

Device and method for preparing filament yarn of composite nanofibers. The device includes pairs of electrospinning nozzles on a frame and filament guiding roller pair under the frame. The spouts of each pair of nozzles are oppositely facing. The method includes feeding polymer solutions to the pairs of nozzles, applying high DC voltage with opposite polarity respectively to each one of the pairs of nozzles, forming composite nanofibers by attracting nanofibers with opposite charge from each nozzle and striking together of the charged nanofibers, pulling/stretching the composite nanofibers to form filament yarn of composite nanofibers, drawing down the filament yarn of composite nanofibers from the first pair of nozzles and using it as a carrier to receive the nanofibers with opposite charge electrospun from the second pair of nozzles and coated by the same so as to form multi-layer (e.g., two- or more-layer) filament yarn of composite nanofibers.

RELATED APPLICATIONS This application is a continuation of U.S. patent application Ser. No. 12/242,870, filed Sep. 30, 2008 now U.S. Pat. No. 7,870,357, which is a continuation of U.S. patent application Ser. No. 11/733,167, filed Apr. 9, 2007, now U.S. Pat. No. 7,437,527, which is a continuation of U.S. patent application Ser. No. 11/181,412, filed Jul. 13, 2005, now U.S. Pat. No. 7,421,548, which is a continuation of U.S. patent application Ser. No. 11/090,343, filed Mar. 24, 2005, now U.S. Pat. No. 7,047,375, which is a continuation of U.S. patent application Ser. No. 10/014,457, filed Dec. 11, 2001, now U.S. Pat. No. 6,889,300, which is a continuation of U.S. patent application Ser. No. 09/169,736, filed Oct. 9, 1998, now U.S. Pat. No. 6,343,352, which claims benefit of U.S. Provisional Patent Application Ser. No. 60/061,503, filed Oct. 10, 1997, which are incorporated herein by reference. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the transfer of data in digital systems. More specifically, the present invention relates to a protocol and apparatus that provide improved interconnect utilization. In particular, a two-step write operation according to the present invention avoids resource conflicts, thus permitting read and write operations to be issued in any order while maintaining continuous data traffic. 2. Description of the Related Art A computer, such as a computer system 10 shown in FIG. 1A , typically includes a bus 12 which interconnects the system's major subsystems such as a central processing unit (CPU) 14 , a main memory 16 (e.g., DRAM), an input/output (I/O) adapter 18 , an external device such as a display screen 24 via a display adapter 26 , a keyboard 32 and a mouse 34 via an I/O adapter 18 , a SCSI host adapter 36 , and a floppy disk drive 38 operative to receive a floppy disk 40 . SCSI host adapter 36 may act as a storage interface to a fixed disk drive 42 or a CD-ROM player 44 operative to receive a CD-ROM 46 . Fixed disk 42 may be a part of computer system 10 or may be separate and accessed through other interface systems. A network interface 48 may provide a connection to a LAN (e.g., a TCP/IP-based local area network (LAN)) or to the Internet itself. Many other devices or subsystems (not shown) may be connected in a similar manner. Also, it is not necessary for all of the devices shown in FIG. 1A to be present to practice the present invention, as discussed below. The configuration of the devices and subsystems shown in FIG. 1A may vary substantially from one computer to the next. In today's high-performance computers, the link between the CPU and its associated main memory (e.g., CPU 14 and main memory 16 , respectively) is critical. Computer programs currently available place imposing demands on a computer's throughput capabilities. This need for increasingly higher bandwidth will continue. One method for improving the throughput of this interface is to provide a dedicated bus between CPU 14 and main memory 16 . Such a bus is shown in FIG. 1A as a memory bus 50 . Memory bus 50 allows CPU 14 to communicate data and control signals directly to and from main memory 16 . This improves computational performance by providing a pathway directly to the system's main memory that is not subject to traffic generated by the other subsystems in computer system 10 . In such systems, the pathway between main memory 16 and bus 12 may be by way of a direct memory access (DMA) hardware construct for example. FIG. 1B illustrates a block diagram in which components (e.g., CPU 14 and main memory 16 ) communicate over an interconnect 60 in order to process data. Interconnect 60 is a generalization of memory bus 50 , and allows one or more master units such as master units 70 ( 1 )-(N) and one or more slave units, such as slave units 80 ( 1 )-(N). (The term “N” is used as a general variable, its use should not imply that the number of master units is identical to the number of slave units.) Components attached to interconnect 60 may contain master and slave memory elements. In the case where interconnect 60 serves as memory bus 50 , CPU 14 communicates with main memory 16 over interconnect 60 using pipelined memory operations. These pipelined memory operations allow maximum utilization of interconnect 60 , which is accomplished by sending data over interconnect 60 as continuously as is reasonably possible given the throughput capabilities of main memory 16 . The block diagram of FIG. 1B is applicable to intrachip, as well as interchip, communications. It will be understood that one or more of slave units 80 ( 1 )-(N) may consist of other components in addition to memory (e.g., a processor of some sort). The block diagram of FIG. 1B can, of course, be simplified to the case of a system having only a single master. FIG. 1C shows a memory device 100 . Memory device 100 might be used in a computer system, for example, as main memory 16 of computer system 10 , or in combination with similar devices to form main memory 16 . Memory device 100 is capable of being read from and written to by a memory controller (not shown). An interconnect 110 is used to communicate control information over control lines 112 and data over data lines 114 from the memory controller to memory device 100 . Interconnect 110 is thus analogous to memory bus 50 . To support such communications and the storage of data, memory device 100 typically includes three major functional blocks. The first of these, a transport block 120 , is coupled to interconnect 110 . Interconnect 110 , which includes control signal lines 112 and data signal lines 114 , is used to read from and write to memory device 100 . Interconnect 110 provides the proper control signals and data when data is to be written to memory device 100 . Transport block 120 receives these signals and takes the actions necessary to transfer this information to the remaining portions of memory device 100 . When memory device 100 is read, transport block 120 transmits data as data signal lines 114 in response to control signal lines 112 . Transport block 120 includes a control transport unit 122 which receives control signal lines 112 , and controls a read data transport unit 124 and a write data transport unit 126 to support the communication protocol used in transferring information over interconnect 110 (e.g., transferring information between CPU 14 and main memory 16 over memory bus 50 ). In its simplest form, transport block 120 is merely wiring, without any active components whatsoever. In that case, control transport unit 122 would simply be wires, as read data transport unit 124 and write data transport unit 126 would require no control. In effect, transport block 120 is not implemented in such a case. Another possible configuration employs amplifiers to provide the functionality required of transport block 120 . In yet another possible configuration, transport block 120 includes serial-to-parallel converters. In this case, control transport unit 122 controls the conversion performed by read data transport unit 124 and write data transport unit 126 (which would be the serial-to-parallel converters). Other equivalent circuits may also be used with equal success. The second of the major functional blocks is an operations block 130 . Operations block 130 receives control information from transport block 120 , more specifically from control transport unit 122 , which provides the requisite signals to a control operation unit 150 . In FIG. 1C , control operation unit 150 is implemented as an architecture designed to control generic DRAM memory cells. A specific DRAM memory cell architecture (or other architecture), however, may require different control signals, some or all of which may not be provided in the architecture shown in FIG. 1C . Control operation unit 150 includes a sense operation unit 132 , a precharge operation unit 134 , and a core transfer operation unit 136 . Data being read is transferred from the third functional block, a memory core 180 , via data I/O bus 185 to a read data operation unit 160 . From read data operation unit 160 , the data being read is transferred to read data transport unit 124 (and subsequently, onto data signal lines 114 ) in response to control signals from control operation unit 150 . Read data operation unit 160 may consist of, for example, data buffers (not shown) that buffer the outgoing data signals to drive read data transport unit 124 . Data to be written is transferred from write data transport unit 126 to a write operation unit 170 in response to control signals from control transport unit 122 (if used) and control operation unit 150 . Write data operation unit 170 receives write data from write transport unit 126 , which is passed on to memory core 180 via data I/O bus 185 . As shown, write data operation unit 170 may be controlled by core transfer operation unit 136 . Write data operation unit 170 may consist of, for example, data buffers (not shown) that buffer the incoming data signals. Write data operation unit 170 may also contain mask buffers that buffer mask information received from write data transport unit 126 . As with data buffering, these actions may be taken under the control of core transfer operation unit 136 . The mask information is then passed to memory core 180 via data I/O bus 185 , as well. The mask information is used by the memory core to selectively write parts of the data within the memory core. Alternatively, no mask is employed, with the result that all the data is written unconditionally. The circuitry of control operation unit 150 may take any number of appropriate configurations, depending in part on the architecture of the memory core employed. For example, the memory cells of memory core 180 may be static random access memory (SRAM) cells, read-only memory (ROM) cells (which can, of course, only be read), dynamic RAM (DRAM) cells, or another type of memory cell. The type of memory cell employed in memory core 180 affects the architecture of control operation unit 150 , as different memory cells often require different control signals for their operation. Operational block 130 thus contains core transfer operation unit 150 , read data operation unit 160 , and write data operation unit 170 . Again, in the simplest configuration of transport block 120 , the subsystems of transport block 120 are merely wires. Moreover, the functionality provided by the subsystems of transport block 120 is merely one of transferring data and control information. Assuming that the memory core employs DRAM-type memory cells, operations which may be performed on memory core 180 (referred to herein as core operations) may be generalized into four primary categories: 1) Precharge; 2) Sense; 3) Read; and 4) Write. While these generalized operations are dealt with in detail later in this section, they are introduced here to illustrate the following effects on the block diagram of FIG. 1C . Given the generalized operations to be performed, the circuitry of control operation unit 150 may be logically divided into the three subsystems mentioned previously: sense operation unit 132 , precharge operation unit 134 , and core transfer operation unit 136 . Core transfer operation unit 136 controls read data operation unit 160 and write data operation unit 170 when transferring data from and to memory core 180 , respectively (i.e., read and write operations). Core transfer operation unit 136 also controls memory core 180 , causing memory core 180 to store write data and output read data. Precharge operation unit 134 controls memory core precharge operations, which precharge the selected banks in memory core 180 . Sense operation unit 132 is provided for the control of memory core sense operations. The subsystems of operations block 130 uses the control information received to coordinate movement of control and data information to and from memory core 180 . Read data operation unit 160 and a write data operation unit 170 contain circuitry specific to the functions which read and write data from and to memory core 180 , respectively. Core transfer operation unit 150 contains circuitry used to control memory core 180 , including circuitry for the control of read and write operations. Core interface signals 190 are provided to control memory core 180 . FIG. 2 illustrates a memory core 200 , which can serve as memory core 180 in FIG. 1C . Memory core 200 typically includes several basic functional blocks. Memory core 200 is illustrated as including multiple memory banks, memory banks 205 ( 1 )-(N). Alternatively, memory core 200 can be implemented using only a single memory bank (e.g., memory bank ( 1 )). Included in each of memory banks 205 ( 1 )-(N) are a storage array, exemplified by storage arrays 210 ( 1 )-(N), and a set of sense amplifiers, exemplified by sense amplifiers 215 ( 1 )-(N). Storage arrays 210 ( 1 )-(N) are central to the function of memory core 200 , actually holding the data to be stored. Storage arrays 210 ( 1 )-(N) are connected to sense amplifiers 215 ( 1 )-(N) by bit lines 220 ( 1 )-(N), respectively. Such storage arrays are normally organized into rows and, columns of storage cells, each of which typically stores one bit of information, although configurations for storing multiple bits are known in the art. Also included in memory core 200 are a row decoder 225 and a column decoder 230 . A row address 235 is provided to row decoder 225 , along with row control signals 240 , which cause row decoder 225 to latch a row address thus presented. In turn, row decoder 225 presents this address information to memory banks 205 ( 1 )-(N) via row select lines 245 . Similarly, a column address 250 is provided to column decoder 230 , along with column control signals 255 , which cause column decoder 230 to latch a column address thus presented. In turn, column decoder 230 presents this address information to memory banks 205 ( 1 )-(N) via column select lines 260 to select which sense amplifiers are connected to the column amplifiers. The column control signals 255 may include mask bit signals to selectively mask individual sense amplifiers in accordance with a predetermined masking scheme. Column control signals 255 are also provided to column amplifiers 265 . Column amplifiers 265 are coupled to sense amplifiers 215 ( 1 )-(N) by column I/O lines 266 , and amplify the data signals input to and output from sense amplifiers 215 ( 1 )-(N). Column amplifiers 265 are also coupled to data I/O bus 185 (from FIG. 1C ), permitting the communication of control signals from operations block 130 to the various control structures within memory core 200 . The signals aggregated as core interface signals 190 (as illustrated in FIG. 1C ) thus include row address 235 , row control signals 240 , column address 250 , and column control signals 255 . Thus, the interface to a memory core generally consists of a row address, a column address, a datapath, and various control signals, including mask signals. As shown in FIG. 2 , memory cores can have multiple banks, which allows simultaneous row operations within a given core. The use of multiple banks improves memory performance through increased concurrency and a reduction of conflicts. Each bank has its own storage array and can have its own set of sense amplifiers to allow for independent row operation. The column decoder and datapath are typically shared between banks in order to reduce cost and area requirements, as previously described. FIG. 3 illustrates a generic storage array 300 , in which data is stored in storage cells 305 ( 1 , 1 )-(N,N). Thus, storage array 300 is capable of storing N 2 bits, using a common storage cell implementation. As shown, each one of word lines 310 ( 1 )-(N) accesses a row of storage cells 305 ( 1 , 1 )-(N,N) (e.g., storage cells 305 ( 1 , 1 )-( 1 ,N)), which in turn transfers the stored data onto internal bit lines 320 ( 1 )-(N). Internal bit lines 320 ( 1 )-(N) emerge from storage array 300 as bit lines 220 (i.e., an aggregate of bit lines 220 ( 1 )-(N), which are connected to sense amplifiers 215 ( 1 )-(N)). Accessing the information in a storage array (i.e., reading data stored in storage arrays 210 ( 1 )-(N)) is typically a two step process. First, data is transferred between storage array 300 and a corresponding set of sense amplifiers 215 ( 1 )-(N). Next, the data is transferred between the sense amplifiers involved and the column amplifiers 265 . Certain memory core architectures do away with the column amplifiers, transferring the data from the sense amplifiers directly to the data I/O bus (i.e., data I/O bus 190 ). The first major step, transferring information between storage arrays 210 ( 1 )-(N) and sense amplifiers 215 ( 1 )-(N), is known as a “row access” and is broken down into the minor steps of precharge and sense. The precharge step prepares the sense amplifiers and bit lines for sensing, typically by equilibrating them to a midpoint reference voltage. During the sense operation, the row address is decoded, a single word line is asserted, the contents of the storage cell is placed on the bit lines, and the sense amplifiers amplify the value to full rail (i.e., a full digital high value), completing the movement of the information from the storage array to the sense amplifiers. Of note is the fact that the sense amplifiers can also serve as a local cache which stores a “page” of data which can be more quickly accessed with column read or write accesses. The second major step, transferring information between the sense amplifiers and the interface, is called a “column access” and is typically performed in one step. However, variations are possible in which this major step is broken up into two minor steps, e.g. putting a pipeline stage at the output of the column decoder. In this case the pipeline timing should be adjusted to account for the extra time involved. These two steps give rise to the four basic memory operations mentioned previously: precharge, sense, read, and write. A typical memory core can be expected to support these four operations (or some subset thereof). However, certain memory types may require additional operations to support architecture-specific features. The general memory core described provides the basic framework for memory core structure and operations. However, a variety of memory core types, each with slight differences in their structure and function, exist. The three major memory core types are: Dynamic Random-Access Memory (DRAM) Static Random-Access Memory (SRAM) Read-Only Memory (ROM) The structure of a conventional DRAM core is similar to the generic memory core in FIG. 2 . Like memory core 200 , the conventional DRAM structure has a row and column storage array organization and uses sense amplifiers to perform row access. As a result, the four primary memory operations (sense, precharge, read and write) are supported. Memory core 200 includes an additional column amplifier block and column amplifiers 265 , which are commonly used to speed column access in DRAM (and other memory core types, as well). Also illustrated by FIG. 2 is the use of multiple banks, a common configuration for conventional DRAM cores. As before, the row decoder, column decoder, and column amplifiers are shared among the banks. An alternative configuration replicates these elements for each bank. However, replication typically requires larger die area and thus incurs greater cost. Inexpensive core designs with multiple banks typically share row decoders, column decoders, and column datapaths between banks to minimize die area, and therefore cost. Conventional DRAM cores use a single transistor cell, known as a 1T cell. The single transistor accesses a data value stored on a capacitor. The 1T cell is one of the storage cell architectures that employs a single bit fine, as referred to previously. This simple storage cell achieves high storage density, and hence a low cost per bit. However, designs employing such storage cells are subject to two limitations. First, such storage cell architectures exhibit slower access times than certain other storage cells, such as SRAM storage cells. Since the passive storage capacitor can only store a limited amount of charge, row sensing for conventional DRAM storage cells (i.e., 1 T cells) takes longer than for other memory types with actively-driven cells (e.g., SRAM storage cells). Hence, the use of a 1 T storage cell architecture generally results in relatively slow row access and cycle times. Second, such storage cell architectures require that the data held in each cell be refreshed periodically. Because the bit value is stored on a passive capacitor, the leakage current in the capacitor and access transistor result in degradation of the stored value. As a result, the cell value must be “refreshed” periodically. The refresh operation consists of reading the cell value and re-writing the value back to the cell. These two additional memory operations are named refresh sense and refresh precharge, respectively. In traditional cores, refresh sense and refresh precharge were the same as regular sense and precharge operations. However, with multiple bank cores, special refresh operations may be advantageous to enable dedicated refresh circuits and logic to support multibank refresh. To perform a row access in a conventional DRAM having a single bank, bit lines 220 ( 1 )-(N) and sense amplifiers 215 ( 1 )-(N) must first be precharged, typically to one-half of the supply voltage (Vdd/2). The row precharge time, t RP , is the time required to precharge the row to be sensed. To perform a sense operation, row decoder 225 drives a single word line (e.g., one of word lines 310 ( 1 )-(N)) to turn on each of the memory cells' access transistors (not shown) in the row being sensed. The charge on each of the memory cells' storage capacitors (also not shown) transfers to its respective bit line, slightly changing the corresponding bit line's voltage. The sense amplifier detects this small voltage change and drives the bit lines to either Vdd or ground, depending on the voltage change produced by the capacitor's charge. The wordline must be held high a minimum time period of t RAS,MIN to complete the sensing operation. At some time before the bit lines reach their final value, a column read or write access can begin. The time between the start of the sense operation and the earliest allowable column access time is t RCD (the row-to-column access delay). The total time to perform both precharge and sense is t RC , the row cycle time, and is a primary metric for core performance. Row access timing for DRAMs with multiple banks, such as that illustrated in FIG. 2 , differs slightly from the preceding example. The delay t RP specifies the minimum delay between precharge operations to different banks. This indicates that the precharge circuitry is able to precharge the next row (which may be the same row originally precharged) after a period of t PP . Typically, t PP is approximately equal (or even less than) t RP , assuming the same memory core and device architecture are employed. Similarly, t SS specifies the minimum delay between performing sense operations on different banks. As before, the sensing on different banks can be carried out more quickly than repeated sensing on the same bank. These parameters indicate that, while the precharge circuitry can precharge a row every t PP seconds and sense circuitry can sense every t SS seconds (both of which are usually measured in ns), a single bank's storage array can only be precharged (or sensed) every t RC seconds (measured in ns). Thus, a memory core employing multiple banks can be read from and written to more quickly in situations where different banks are being accessed. Typical column cycle times and access times greatly depend on the type of sense amplifier circuit employed. This is because the sense amplifiers drive the selected data onto the column data I/O wires, and must be able to drive the capacitance that those wires represent (i.e., the amplifier must be able to charge that capacitance in the requisite time). Increased speeds can be achieved by improving the sense amplifier's drive capability, thus charging the column data VO wires capacitance more quickly. This could be done by using more or larger transistors in the sense amplifier circuit. However, such modifications greatly increase die area, and so cost, especially because the sense amplifier circuit is so heavily replicated. Thus, the desire to minimize the die area of commodity DRAMs limits the further reduction of column access speeds by this technique. In a conventional DRAM, the column decoder's output drives a single column select line, which selects some or all of the outputs from the sense amplifiers. The column decoder's output may be placed in a register for pipelined designs. The selected sense amplifiers then drive their respective data onto the column I/O wires. To speed column access time, the column I/O lines are typically differential and sensed using differential column amplifiers (e.g., column amplifiers 265 in FIG. 2 ), which amplify small voltage differences on the column I/O wires and drive data I/O bus 185 . The width of the column I/O bus determines the data granularity of each column access (also known as CAS block granularity). Unfortunately, the preceding DRAM timing parameters (and others) can vary widely due to variations in manufacturing processes, supply voltage, operating temperature, and process generations, among other factors. In order for a memory architecture to operate properly given such variations, it is important for a DRAM protocol to be able to support these varied row and column timings. In a conventional DRAM, column control signals 255 of FIG. 2 typically include a column latch signal, a column cycle signal, and write mask signals. The column latch signal precedes the column cycle signal, and causes column decoder 230 to latch the column address (column address 250 ). In this type of architecture, the column cycle signal indicates the actual beginning of the column access process, and therefore is required to wait for the column address to be latched. Some DRAM memory cores also include the ability to mask write data. With masking, a write operation is performed such that some bits or bytes of the datapath are not actually written to the storage array depending on the mask pattern. Typically, the mask pattern is delivered to the column amplifier write circuit, which inhibits the write data in an appropriate manner. Moreover, data I/O bus 185 and/or column I/O lines 266 can be either bidirectional, in which case write and read data are multiplexed on the same bus, or unidirectional, in which case separate write and read datapaths are provided. While FIG. 2 illustrates data I/O bus 185 as a bidirectional bus, the use of a unidirectional bus can easily be envisioned. FIG. 2 may also be used to illustrate a memory core employing an SRAM storage cell architecture. The typical SRAM memory core architecture shares the core structure and functionality of the conventional DRAM memory architecture discussed previously. Moreover, accesses are performed in a two-step process similar to that used in accessing data held in a DRAM memory core. First, during the sense operation, the information is transferred between the storage array and the sense amplifiers. Second, in the column access operation, the information is transferred between the sense amplifiers and the interface. Another similarity to DRAM is the need to precharge the bitlines prior to sensing operations, although typical precharge value is the supply voltage, not half of the supply voltage normally used in conventional DRAM architectures. SRAM memory cores differ markedly from DRAM memory cores in the architecture of the storage cells used in each. In an SRAM memory architecture, data is stored statically, typically using a circuit of several transistors. A typical SRAM storage cell uses cross-coupled CMOS inverters to store a single data bit, and employs the bit line pairs as illustrated in FIG. 3 (internal bit lines 220 ( 1 )-(N), e.g., differential bit lines). A word line (one of word lines 310 ( 1 )-(N)) turns on access transistors within the selected SRAM storage cells (e.g., storage cells 305 ( 1 , 1 )-( 1 ,N)), which connect each cell in the row to the differential bit lines (internal bit lines 320 ( 1 )-(N)). Unlike a DRAM cell, however, each SRAM storage cell actively drives the stored value onto its respective bit line pair. This results in faster access times. The static nature of the SRAM cell also eliminates the need for refresh operations. However, the static cell uses more transistors and therefore requires more area than a DRAM cell. As with the DRAM, the four primitive operations of an SRAM are sense, precharge, read, and write. However, because an SRAM storage cell operates so quickly, precharge and sense may be performed for each read (even within page). This is in contrast to DRAM devices (known as page-mode DRAM), which save time by storing a page of data in the device's sense amplifiers, as noted previously. Read-only memory (ROM) cores store information according to an electrical connection at each cell site which join rows to columns. Typically, a single transistor forms the electrical connection at each cell site. There are a variety of ROM cell types, including erasable programmable ROM storage (EPROM), electrically erasable programmable ROM (EEPROM), flash ROM, and mask-programmable ROM. Their differences lie in the type of transistor used in each architecture's storage cell. However, ROMs share the storage array architecture illustrated in FIG. 2 , which requires a row and column decode of the address for each data access. Unlike SRAM and DRAM devices, not all ROM devices include sense amplifier circuits (e.g., sense amplifiers 215 ( 1 )-(N)). Sense amplifiers are only used in certain ROM architectures which require fast access times. For such ROM devices, the primitive operations are sense, precharge, and read. For slower ROM devices that do not use sense amplifiers, the selected data values are driven directly from the storage cell circuitry to output amplifiers, which in turn drive the data I/O bus. For these ROMs, the single primitive operation is read. A significant limitation on the effective bandwidth of memory bus 50 (i.e., interconnect 110 ) can arise as the result of the issuance of certain combinations of read and write operations. For example, the issuance of certain read/write combinations may intrinsically introduce inefficiencies in the utilization of interconnect 110 . For example, a delay (also known as a data bubble) may occur when a write operation is followed by a read operation. Because the write data is immediately present on interconnect 110 and the read data is not present until a later time (determined by the access time of the device being read), a data bubble between the write data and read data naturally occurs. This data bubble obviously impairs the efficient utilization of interconnect 110 and the column I/O datapath. Moreover, because it is preferable to share certain interconnect resources 110 , certain combinations of read and write operations are not allowable. These combinations result in data bubbles between the data transferred by certain of the read and write operations within these combinations. These delays, also known as data bubbles, are of particular importance in systems which are configured to maintain full or almost full utilization of interconnect 110 by constantly (or nearly constantly) transferring data to and from components attached thereto (e.g., CPU 14 and main memory 16 ), and within the memory devices which make up main memory 16 . In a conventional memory of the design shown in FIGS. 2 and 3 , the resource ordering for read and write operations differs slightly. A read operation uses resources in the order: control signal lines 112 column I/O datapath (including data I/O bus 185 and column I/O lines 266 ) data signal lines 114 while a write operation uses them in the order: control signal lines 112 data signal lines 114 column I/O datapath (including data I/O bus 185 and column I/O lines 266 ) These differences in the ordering of resource usage give rise to resource conflicts when read and write operations are issued because control signals issued over control signal lines 114 cause data to be transferred immediately, in relative terms. Thus, if data signal lines 114 and the column I/O datapath are bidirectional (as is desirable), conflicts can occur between read data and write data because each transfer requires the use of these resources. What is therefore desirable is a protocol and apparatus that provide improved interconnect utilization. In particular, the protocol should permit read and write operations to be issued in any order without the need to delay one or more of the operations because of resource conflicts. Moreover, the apparatus should be configured to perform this function in the case of bidirectional interconnect and column I/O datapaths. SUMMARY OF THE INVENTION The present invention relates to the transfer of data in computer systems. More specifically, the present invention relates to a protocol and apparatus that provide improved interconnect utilization. In particular, a two-step write operation according to the present invention avoids resource conflicts, thus permitting read and write operations to be issued in any order while maintaining continuous data traffic. In one embodiment of the present invention, a method for storing data in a memory device is described. The method includes the following steps. The method employs a two-step technique which allows the out-of-order completion of read and write operations. When a write operation requires a resource needed for the completion of a read operation, the data being written is stored in a write data buffer in the memory device. The write data is stored in the buffer until a datapath is available to communicate the data to the memory device's memory core. Once the resource is free (or the memory device, or its controller force the write to complete) the data is written to the memory core of the memory device using the now-free datapath. In another embodiment of the present invention, a memory device is described. The memory device includes a memory core in which data may be stored. The memory core includes a storage array, in which the data is actually stored, and a bidirectional datapath coupled to the storage array, which allows data to be read from and written to the storage array. The memory device also includes a datapath that is coupled to the memory core's bidirectional datapath, and allows data to be communicated into and out of the memory device. The memory device also includes a write data buffer coupled to the datapath. This data buffer is configured to store the data to be written to the memory core. In this manner, the data buffer allows one or more quanta of data to be stored for a period of time, again allowing their related write operations to complete in an out-of-order sequence by waiting until the memory core's bidirectional datapath is free. These and other embodiments of the present invention, as well as its advantages and features are described in more detail in conjunction with the text below and attached figures. BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding of the invention, reference should be made to the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. 1A is a block diagram of a computer system of the prior art. FIG. 1B is a block diagram of an interconnect of the prior art. FIG. 1C is a block diagram of a generic memory device of the prior art. FIG. 2 is a block diagram of a generic memory core of the prior art. FIG. 3 is a block diagram of a generic storage array of the prior art. FIG. 4 is a timing diagram showing the data bubble that can occur in a memory device. FIG. 5 is a timing diagram showing the reduction of the data bubble of FIG. 4 . FIG. 6 is a block diagram of one embodiment of a memory device containing circuitry that reduces the data bubble of FIG. 4 . FIG. 7 is a block diagram of one embodiment of a memory device containing circuitry that may be utilized in accordance with the present invention. FIG. 8 is a timing diagram showing a data bubble which may be remedied using the circuit of FIG. 7 . FIG. 9 is a block diagram of one embodiment of a memory device containing circuitry according to the present invention. FIG. 10 is a timing diagram showing the reduction of the data bubble using the circuitry of FIG. 9 . FIG. 11 is a block diagram of one embodiment of a memory device containing circuitry according to the present invention. FIG. 12 is a timing diagram showing the reduction of the data bubble using the circuitry of FIG. 11 in the case of a write operation followed by a read operation. FIG. 13 is a timing diagram showing the reduction of the data bubble as in FIG. 9 , but with a no-op operation between the write and read operations. FIG. 14 is a timing diagram showing the reduction of the data bubble using the circuitry of FIG. 11 in a second case of a write operation followed by a read operation. FIG. 15 is a block diagram of one embodiment of a memory device containing circuitry according to the present invention which provides for bypassing. FIG. 16 is a block diagram of one embodiment of a blender, as illustrated in FIG. 15 . FIG. 17 is a timing diagram illustrating the operation of the circuitry of FIG. 15 . FIG. 18 is a timing diagram illustrating the operation of the circuitry of FIG. 15 . Like reference numerals refer to corresponding parts throughout the drawings. DESCRIPTION OF THE PREFERRED EMBODIMENTS I. Introduction The present invention provides a protocol, which may be implemented in a memory device, that supports improved utilization of an interconnect between a bus master (e.g., CPU 14 of FIG. 1A ) and a bus slave (e.g., main memory 16 of FIG. 1A ). In particular, a two-step write operation is used to avoid resource conflicts. In this manner, a memory device according to the present invention permits the issuance of read and write operations in any order while maintaining continuous data traffic. A memory device according to the present invention maintains continuous data traffic by employing a two-step technique which allows the out-of-order completion of read and write operations. When a write operation requires a resource needed for the completion of a read operation, the data being written is stored in a write data buffer in the memory device. The write data is stored in the buffer until a datapath is available to communicate the data to the memory device's memory core. Once the resource is free (or the memory device, or its controller force the write to complete) the data is written to the memory core of the memory device using the now-free datapath. II. The Use of Delayed Write Operations FIG. 4 illustrates a situation in which a data bubble is formed by a write operation followed by a read operation. Write operations 400 and 405 , followed by a read operation 410 and write operations 415 and 420 , are communicated over control signal lines 112 to memory device 100 , which forwards this control information to memory core 200 . Write operations 400 and 405 input write data 425 and 430 to memory device 100 via data signal lines 114 . Write data 425 and 430 are communicated to memory core 200 , and then to one or more of memory banks 205 ( 1 )-(N) via column I/O lines 266 . Read operation 410 reads data from memory device 100 by causing memory core 200 to output read data 435 on column I/O lines 266 , as shown in FIG. 2 , and then to data I/O bus 185 . Read data 435 is then communicated to data signal lines 114 via operations block 130 and transport block 120 . In a fashion similar to the preceding write operations, write operations 415 and 420 input write data 440 and 445 to memory device 100 via data signal lines 114 , and then to one or more of memory banks 205 ( 1 )-(N) via column I/O lines 266 . As can be seen in FIG. 4 , no resource conflicts are observed in the case where a write operation follows another write operation (e.g., write operations 400 and 405 ). Moreover, data can also be efficiently transferred in the case where a write operation follows a read operation (e.g., read operation 410 and write operation 415 ). This is because the read data can followed immediately with write data. Although not illustrated in FIG. 4 , the case where a read operation is followed by another read operation also experiences no resource conflicts. These combinations fail to experience such conflicts because the data transfer requested by the given operations are not in contention for the same resources. For example, write data 425 is transferred from data signal lines 114 to column I/O lines 266 before write data 430 needs data signal lines 114 . Thus, no resource conflict occurs. However, a data bubble 450 occurs in the transfer of data on interconnect 110 in the case where a read operation follows a write operation (e.g., write operation 405 and read operation 410 ). In that case, because the write data is presented immediately and the read data is not present until a later time, a data bubble between the write data and read data naturally occurs. The data bubble appears regardless of whether write operation 405 and read operation 410 are directed to the same or to different memory devices (e.g., memory devices within main memory 16 ) attached to interconnect 110 . It is noted that the delay from control signals 112 to column I/O lines 266 is identical for read and write operations. The solution to the problem created by data bubble 450 is to match the timing of the write operation's use of datapath resources to the read operation's use of those resources. Typically, the optimal delay for a write operation does not quite match the delay for a read operation because interconnect 110 has an intrinsic turnaround time. This turnaround time is the time required to switch the direction of the circuitry which drives interconnect 110 (e.g., the time it takes to switch the direction of bidirectional buffers or amplifiers). Instead, the delay for a write operation should be equal to the minimum read delay minus the minimum turnaround time for interconnect 110 . There is no need to change the control-to-data delay for the write operation as a function of memory device position on interconnect 110 because the turnaround delay grows as the read delay grows. FIG. 5 shows the result of delaying the write to match the read. The delay from the issuance of the write control to the beginning of the data write is set to match the delay from the issuance of the read control to the beginning of the data read. As long as different column data paths are used to perform the read column cycle and the write column cycle (i.e., the read and write operations are to different memory devices), the data bubble is shrunk to the minimum required by channel turnaround requirements and is no longer a function of control or data resource conflicts. This is illustrated in FIG. 5 by the use of column I/O lines 266 (A) and 266 (B), each of which designates the column I/O lines of separate memory devices ((A) and (B)). As long as different column data paths are used to perform the read column cycle and the write column cycle, the data bubble is shrunk to the minimum required by channel turnaround requirements and is no longer a function of control or data resource conflicts. The need for this restriction is illustrated by the fact that read data 435 is accessed at the same time as write data 425 and write data 430 . Moreover, since write latency is not vitally important to application performance, this modification does not cause any loss in application performance, so long as the writes and reads are directed to separate column data paths and the write occurs before the expiration of t RAS,MIN (the minimum time between sensing a row and precharging another row in the same bank). Delaying write operations thus helps optimize data bandwidth efficiency over a bidirectional datapath. The technique adds a delay between control signals indicating a write operation and data being written so that the delay between the two is similar to that of read operations. Maintaining this “pattern” for read and write operations improves pipeline efficiency over a bidirectional datapath. As noted, this is true only for operations to separate column resources. It is to be understood that, due to the timing relationship between column control signals and column I/O data, the limitations experienced by one column resource are substantially the same constraints experienced by the other column resource. In other words, because the time between a column control operation and the data resulting from that operation is so short, a resource conflict on one column resource will imply a resource conflict on the other column resource. FIG. 6 illustrates the modifications to memory device 100 necessary to provide delayed write functionality. Column access control information is delayed for writes relative to when the column control information is presented to the core for reads by a write delay block 600 . The outputs of write delay block 600 and control operation block 150 are coupled to a multiplexer 610 which selects between these outputs, under the control of control operation block 150 . The output selected depends upon the type of operation to be performed (i.e., whether the current operation is a read or a write). If the current operation is a read operation, control operation block 150 to select the output of control operation block 150 , while a write operation would cause control operation block 150 selects the output of write delay block 600 . While a multiplexer is shown in FIG. 6 , other embodiments of this mechanism may be employed, as would be obvious to those skilled in the art. For example, a state machine could be used to introduce new delaying state transitions when the operation is a write. However, even if a delayed write technique is employed, a data bubble 450 may still be observed in the transfer of data over column I/O lines 266 (and data I/O bus 185 ). For example, given the operations illustrated in FIG. 5 , if the operations are all to be performed within a single device, there will obviously be a resource conflict on column I/O lines 266 , as well as on column control signals 255 (assuming that device has bidirectional datapaths). The resource conflict which gives rise to data bubble 450 occurs within memory device 100 . More specifically, the resource conflict occurs on the datapath within memory core 200 . This is because column I/O lines 266 are bidirectional, as is data I/O bus 185 . Column I/O lines 266 are normally designed to be bidirectional to reduce the cost and area of the given memory design. As noted, the offending write and read operations must be directed to the same device for this phenomenon to occur. However, this resource conflict could still exist notwithstanding the use of delayed write techniques. The fundamental problem is the resource conflict which occurs when a read and a write operation require the use of a device's column resources. Thus, a solution to the problem of a resource conflict with regard to a device's column resources is made necessary by such a situation. III. The Use of Two-Step Write Operations If a write operation is patterned so that the data interconnect utilization is not limited by read/write conflicts when employing independent column paths, the case of using a single column path to achieve the same utilization must be addressed, in order to avoid data bubbles within memory device 100 . The root of the problem exposed in this section is the interaction of the bidirectional data interconnect resource with the bidirectional column I/O resource. We could resolve this problem by making one or both of these resources unidirectional. (The two-step write technique disclosed herein would, of course, only be applicable to resolving a conflict on a column resource). In the preferred embodiment we make them both bidirectional for cost reasons. It is possible that changes in manufacturing technology would make it cost effective for one or the other of the data resources to be unidirectional. If nothing more than delaying write operations is done, then a write followed by a read results in the timing shown in FIG. 5 . As noted, a delayed write causes a delay for a read to the same device because the write operation is committed once the write control information is presented on the control interconnect and so the column circuitry must wait for the write data so that it can complete the write into memory core 180 , using the column I/O resource before the core access step of the read operation can begin. This not only wastes bandwidth on the data resource, but also delays the read, raising the average service time for reads. The basic problem is to achieve the timing of the write control, addressing, mask, and data at the memory core implied by FIG. 5 even though the data resource timing has been delayed. This timing of the write information needs to be achieved without introducing the delay shown in FIG. 4 . Moreover, if a write delay is employed, the write must be performed without removing the delay of the write data introduced to avoid the resource contention for interconnect 110 solved by the circuitry of FIG. 6 . One solution is to breakup writes into a two-step sequence. In one step, the data is transferred from the master to a buffer in the memory device. This step will be referred to herein as the transport step. In the second step, the data is transferred from the buffer into the memory core via the column I/O datapath. This step will be referred to herein as the retire step. FIG. 7 shows the structure of the core transfer operation unit 136 , read data operation unit 160 , and write data operation unit 170 for a memory that performs operations that are signaled on the control lines. The operation block 130 of FIG. 1C is shown in greater detail in FIG. 7 . Control signals 700 are received from control transport unit 122 . Transfer, control, distribution, and sequence (TCDS) block 705 produces signals to control the memory core 180 , the read data operation unit 160 , and write data operation unit 170 . TCDS block 705 handles transfer, control, signal distribution, and sequencing responsibilities, in this configuration, as analogous blocks do in the block diagrams described below. Signals 710 are the edge based control signals for the memory core. Signals 715 are signals that are presented to the core for a duration of time, and usually have setup and hold requirements with respect to the transition times of signals 710 , and are produced by control buffer 720 . For a read operation, control buffer 720 receives control signals directly from TCDS block 705 via signals 725 through multiplexer 730 which is controlled by signal 735 . For a write operation, control buffer 720 receives control signals from TCDS block 705 via write control buffer 740 , signals 745 , write control buffer 750 , signals 755 , and multiplexer 730 (under the control of signal 735 ). Write control buffers 740 and 750 are controlled by signals 760 . For write control buffer write operations, signals 710 are timed to correspond to the arrival of the operation to signals 715 . Write control buffers 740 and 750 delay the application of the operation control to the memory core. This delay allows the data corresponding to the buffered write operation to be issued later, better matching the timing of the write operation to that of the read operation. Other embodiments may use fewer or additional blocks to change the amount of the delay. Read data buffer 765 receives read data on signals 770 from memory core 180 , at times controlled by signal 771 . This data is passed on to the transport block 120 via signals 775 . In another embodiment, read data buffer 765 is an amplifier driving signals 775 without timing signal 771 . In yet another embodiment, read data operation unit 160 is comprised only of interconnect. Other variations for read data operation unit 160 are possible, depending on specific drive and timing characteristics of memory core 180 . Write data buffer 780 receives write data from transport block 120 via signals 781 at times controlled by signal 782 . This data is passed on to the memory core 180 via signals 783 . Write mask buffer 785 receives mask data from the transport unit on signals 786 at times controlled by signal 787 . The mask information is passed on to memory core 180 via signals 788 . Mask data is used by memory core 180 to selectively write, or not write, parts of the data within the memory core. In another embodiment, no mask is used, with the result that all the data is written unconditionally. FIG. 8 is a timing diagram illustrating the segregated control and data signals associated with FIG. 1C and FIG. 7 . The control signals 700 are applied to TCDS block 705 . The write data sent to the memory device is delivered on signals 781 , while the read data from the memory device is sent by signals 775 . In one embodiment, the data signal lines are not segregated so that read data and write data are transmitted on the same wires at different times. In another embodiment, the data signal lines are further segregated so that some wires transmit only write data and other wires transmit only read data. The write mask is sent on either the control signal lines 112 , or the data signal lines. In one embodiment, the write mask is sent only on the control signal lines. Alternatively, the write mask may be sent only on data signal lines 114 . In another embodiment, the write mask is sent on both of control signal lines 112 and data signal lines 114 . The highlighted write operation in FIG. 8 shows the write control and the write data being transmitted at separate times on control signal lines 112 and data signal lines 114 , and used to operate the core with signals 710 , 715 , 783 and 788 . The timing relationship, in contrast to FIG. 4 , shows the delay between control and data on control signal lines 112 and data signal lines 114 . After the arrival of the data, the application of control and data and mask signals to memory core 180 is done to complete the operation. The highlighted read operation in FIG. 8 shows the read control being transmitted on control signal lines 112 , which causes memory core 180 to be controlled by signals 710 and 715 . The characteristics of memory core 180 affect the time at which the read data is available and delivered via signals 775 , which are transmitted from memory device 180 on data signal lines 114 . The similar timing relationships for a read operation and a write operation, on control signal lines 112 and data signal lines 114 , allow back-to-back operations for read and write, in either order. In order to do so for a write followed by a read, however, the operations must be directed to a different device, which may be done only in a memory system comprised of multiple memory devices which are all connected by control signal lines 112 and data signal lines 114 . FIG. 8 illustrates that, when a write is followed by a read to the same device, the read operation on wires 710 and 715 must be timed to follow the write operation on the same wires. This necessitates the separation of the two operations on control signal lines 112 and data signal lines 114 , so that a data bubble exists on data signal lines 114 . In one embodiment, the time of both the read control, the read data, the write control and the write data are 4 cycles of a synchronizing clock. In this embodiment, the memory core has timing characteristics supporting the relationships shown in FIG. 8 . For such an embodiment, the loss of utilization of the data signal lines 114 is shown in FIG. 8 as a data bubble of 10 cycles in duration. In other embodiments, the data bubble may be of a different duration and timed by different means. The loss of the utilization for data signal lines 114 causes a decrease in effectiveness for the memory system which contains the memory device. This loss of utilization is significant because the occurrence of writes followed by reads to the same device may be frequent, depending on the usage of the memory system, especially when there are one or a small number of memory devices comprising the memory subsystem connected by control signal lines 112 and data signal lines 114 . FIG. 9 shows the structure of the core transfer operation, read data operation and write data operation units for a memory that performs operations that are signaled on the control lines as soon as is practical. Control signals 700 are received from the transport block 120 . TCDS block 705 , read data operation unit 160 , and write operation unit 170 produce signals to control the memory core 180 . Signals 710 are the control signals for the memory core and are preferably edge based. Signals 715 are signals that are presented to memory core 180 for a duration of time, and usually have setup and hold requirements with respect to the transition times of signals 710 , and are produced by block 720 . For a read operation, control buffer 720 receives control signals directly from block TCDS 705 via signals 725 through multiplexer 730 , which is controlled by signal 735 . For a write operation, control buffer 720 receives control signals from TCDS block 705 via write control buffer 740 , signals 745 , write control buffer 750 , signals 755 and multiplexer 730 . Write buffers 740 and 750 are controlled by signals 760 . For a write operation, signals 760 are timed to correspond to the arrival of the operation via signals 715 . The effect of the write control buffers 740 and 750 is to delay the application of the operation control to the memory core. Another effect of write control-buffers 740 and 750 is to allow storage of the write control information so that they may be passed on to the memory core for operation based on some later control indication, rather than just passing through on some fixed schedule. Other embodiments may use fewer or additional blocks to change the amount of the delay and storage. The operation of write control buffers 740 and 750 of FIG. 9 can thus parallel that of write control buffers 740 and 750 of FIG. 7 , if desired, but need not do so. Read data buffer 765 receives read data on signals 770 from the memory core 180 , at times controlled by signal 771 . The data is passed on to transport block 120 via signals 775 . In another embodiment, read data buffer 765 is an amplifier capable of driving signals 775 , without the need for timing signal 771 . In yet another embodiment, read data operation unit 160 includes only interconnect. Other variations for read data operation unit 160 are possible, depending on specific drive and timing characteristics of the memory core. Write data buffer 13202 receives write data from transport block 120 on signals 781 and is controlled by signal 13201 . Write data buffer 13200 is an additional write data buffer, that is also controlled by signal 13201 so that it passes data through to write data buffer 13200 directly in some cases, but stores the data for later passing to write data buffer 13200 in other cases. The write data buffer 13200 receives write data from write data buffer 1320 via signals 13203 , under the control of signal 13201 , and presents the data to memory core 180 on signals 783 . In an analogous fashion, mask data is passed using signals 786 , 13208 , and 788 with mask data being stored in write mask buffers 13207 and 13205 . Mask data is used by memory core 180 to selectively write, or not write, parts of the data within the memory core. In another embodiment, no mask is used so that all the data is written unconditionally. By providing write data buffer 13200 (and write mask buffer 13205 ), memory device 100 allows write operations to be split into two operations, transport and retire. First, the write data (and mask) is transported to write data buffer 13200 (and write mask buffer 13205 ) using, for example, interconnect 110 . Upon receiving a retire command (in whatever form), the write data is communicated to memory core 180 . This allows write operations, which might otherwise be in contention for the column resources of memory device 100 , to complete at a time when no conflicts exist with regard to the now-available column resources. FIG. 10 is a timing diagram relating the segregated control and data signals from FIG. 1C and FIG. 9 . The control signals are sent via signals 700 . The write data sent to the memory device is received via signals 781 , while the read data from memory device 100 is sent via signals 775 . Write mask data is received via signals 786 . In one embodiment, the data wires are not segregated so that read data and write data are transmitted on the same wires at different times. In another embodiment, the data wires are further segregated so that some wires transmit only write data and other wires transmit only read data. The write mask is sent over either the control wires or the data wires. In one embodiment, the write mask is sent using only the control signal lines. In another embodiment, the write mask is sent using only the data signal lines. In another embodiment, the write mask is sent on both control signal lines and the data signal lines. The write operation labeled “a” in FIG. 10 shows the write control and the write data being transmitted at different times on control signal lines 112 and data signal lines 114 , and used to operate memory 180 core with signals 710 , 715 , 783 , and 788 . The timing relationship is the same as for all the write operations of FIG. 8 . After the arrival of the data, the application of control and data and mask to the memory core is done to fulfill the operation. The highlighted write operation labeled “d” and its predecessor illustrate a different timing relationship. The operation of these writes at memory core 100 via signals 710 and 715 are reordered to follow the read that the writes precede on control signal lines 112 . This timing relationship is made possible by the separation of the control that signals the transport of the write data from the control that causes the write operation at the memory core, referred to as a retire operation. In one embodiment the retire control is a specific operation code as part of a control sequence. This is an example of an explicit retire command. In another embodiment, the retire control is implicitly indicated by the reception of any control that arrives when write data is arrived at 783 and any control is indicated that does not require a read operation to be performed. In another embodiment, the retire control is indicated when write data is arrived at wires 783 and either no further operation is signaled on control signal lines 112 , or any control is indicated that does not require a read operation to be performed. The highlighted read operation in FIG. 10 shows the read control being transmitted on control signal lines 112 , which causes the memory core to be controlled by signals 710 and 715 . The characteristics of memory core 180 affect the time at which the read data is available and delivered via signals 775 , which are transmitted from the memory device on data signal lines 114 . The similar timing relationships for a read operation and a write operation, on control signal lines 112 and data signal lines 114 , allow back-to-back operations for read and write. This may be performed when the operations are to different devices (as in the case illustrated in FIGS. 3 , 7 and 8 ), but also when the operations are to the same device, due to the reordering that the retire control allows. In general, one control indicator is used to send the write data on data signal lines 114 . A retire control indicator is used to perform the operation at the memory core. Additional control indicators may be used to signal any other control information for the write, such as the addresses or masks, as long as all the control information arrives in time for the memory operation indicated by the retire control indicator. The ability to generally perform back-to-back write and read operations allows high utilization of data signal lines 114 providing a high performance memory system. The reordered writes of FIGS. 9 and 10 allow a loss of coherency if the data read is from the same location as one of the writes that has been delayed. The structure indicated relies on the originator of the memory operations to maintain coherency. This may be done in many ways know to one skilled in the art. In one instance, if the read location corresponds to one of the write locations, the read operation is delayed until the corresponding write operation is retired. In another instance, a copy of the write data is maintained by originator and merged with the read information, or replaces the read operation. FIG. 11 shows a structure similar to that of FIG. 9 , except that one bank of the write data and mask buffers is removed, as a cost consideration. In this case, the master unit (e.g., a memory controller) holds the write data (that would normally be held in a write buffer in memory device 100 ) until that data is needed or is scheduled to arrive as the write buffer is freed. FIG. 11 shows the structure of the memory core transfer operation, read data operation, and write data operation units for a memory that performs operations that are signaled on the control lines as soon as is practical. Control signals 700 are received from transport block 120 . TCDS block 705 , read data operation unit 160 , and write operation unit 170 produce signals to control memory core 180 . Signals 710 are the control signals for memory core 180 and are preferably edge based. Signals 715 are signals that are presented to memory core 180 for a duration of time, and usually have setup and hold requirements with respect to the transition times of signals 710 , and are produced by block 720 . For a read operation, control buffer 720 receives control signals directly from block TCDS 705 via signals 725 through multiplexer 730 , which is controlled by signal 735 . For a write operation, control buffer 720 receives control signals from TCDS block 705 via write control buffer 740 , signals 745 , write control buffer 750 , signals 755 and multiplexer 730 . Write buffers 740 and 750 are controlled by signals 760 . For a write operation, signals 710 are timed to correspond to the arrival of the-operation via signals 715 . The effect of the blocks 740 and 750 is to delay the application of the operation control to the memory core. Another effect of write control buffers 740 and 750 is to allow storage of the write control information so that they may be passed on to the memory core for operation based on some later control indication, rather than just passing through on some fixed schedule. Other embodiments may use fewer or additional blocks to change the amount of the delay and storage. Read data buffer 765 receives read data on signals 770 from the memory core 180 , at times controlled by signal 771 . The data is passed on to transport block 120 via signals 775 . In another embodiment, read data buffer 765 is an amplifier capable of driving signals 775 , without the need for timing signal 771 . In yet another embodiment, read data operation unit 160 includes only interconnect. Other variations for read data operation unit 160 are possible, depending on specific drive and timing characteristics of the memory core. Write data buffer 15200 receives write data from transport block 120 on signals 781 and is controlled by signal 782 and presents the data to memory core 180 via signals 783 . In an analogous fashion, mask data is passed using signals 786 and 787 with mask data being stored in write mask buffer 15205 . Mask data is used by memory core 180 to selectively write, or not write, parts of the data within the memory core. In another embodiment, no mask is used so that all the data is written unconditionally. By providing write data buffer 15200 (and write mask buffer 15205 ), memory device 100 allows write operations to be split into two operations, transport and retire. First, the write data (and mask) is transported to write data buffer 15200 (and write mask buffer 15205 ) using, for example, interconnect 110 . Upon receiving a retire command (in whatever form), the write data is communicated to memory core 180 . This allows read operations, which might otherwise be in contention for the column resources of memory device 100 , to complete at a time when no conflicts exist with regard to the now-available column resources. However, unlike the circuit in FIG. 9 , the circuit of FIG. 11 has only one write data buffer, write data buffer 15200 (and so, only one write mask buffer, write mask buffer 15205 ). Thus, to avoid overwriting the data (and mask) held in memory device 100 , the memory controller must hold the last write “transported,” (or schedule its transport to coincide with the freed write buffer) as it cannot necessarily be written (along with the related mask data) to write data buffer 15200 (and write mask buffer 15205 ). Moreover, the memory controller, in such a configuration, must maintain information on the write it is holding, and must be made aware of the retiring of the write held in the memory controller. Thus, the complexity of the memory controller is increased in this embodiment, to provide the necessary capabilities for maintaining and reacting to such information. The benefit of this embodiment, however, is the reduction in complexity enjoyed by memory device 100 . The reduction in complexity of memory device 100 is important for two reasons, among others. First, the cost reduction such a configuration provides to memory device 100 affects the commercial viability of such a system, reducing the cost per chip. Second, because there are far more memory devices than controllers in the average system, the cost of the system also can be expected to drop. Thus, pushing the complexity from the memory devices to the memory controller is an important step in reducing the overall system cost and complexity. FIG. 12 , FIG. 13 and FIG. 14 illustrate that the use of a reduced structure such as that shown in FIG. 11 is still capable of providing the benefits of the two-step write process. FIG. 12 is a timing diagram illustrating the segregated control and data signals from FIG. 11 . FIG. 12 illustrates the use of a two-step write technique in the circuit of FIG. 11 (i.e., with one data buffer), in a situation where a write operation is abandoned in favor of a following read operation, to allow the read operation to complete prior to the write operation requiring the column resources of memory device 100 . FIG. 12 shows that the master unit issuing these read and write operations can abandon one of the write operations to perform the read. It should be noted that write “c” data is overwritten without a write operation being performed for it. In this embodiment, the master unit is assumed to have kept all the necessary information associated with the write operation stored at the master unit so that the write operation can be reissued. The control signals are sent via signals 700 . The write data is sent to the memory device via signals 781 , while the read data from memory device 100 is sent via signals 775 . Write mask data is received via signals 786 . In one embodiment, the data wires are not segregated so that read data and write data are transmitted on the same wires at different times (a bidirectional bus). In another embodiment, the data wires are further segregated so that some wires transmit only write data and other wires transmit only read data (a unidirectional bus). The write mask is sent over either the control wires or the data wires. In one embodiment, the write mask is sent using only the control signal lines. In another embodiment, the write mask is sent using only the data signal lines. In another embodiment, the write mask is sent on both control signal lines and the data signal lines. The write operation labeled “a” in FIG. 12 shows the write control and the write data being transmitted at different times on control signal lines 112 and data signal lines 114 , and used to operate memory 180 core with signals 710 , 715 , 783 and 788 . After the arrival of the data, the application of control and data and mask signals to memory core 180 is done to complete the operation. The highlighted write operation labeled “d” and its predecessor (write operation “c”, which is the write operation that is abandoned) illustrate a different timing relationship. The operation of write operation “d” at memory core 100 via signals 710 and 715 is reordered to follow the read that the write precedes on control signal lines 112 . This timing relationship is made possible by the separation of the control that signals the transport of the write data from the control that causes the write operation at the memory core, referred to as a retire operation. In one embodiment the retire control is a specific operation code as part of a control sequence. This is an example of an explicit retire command. In another embodiment, the retire control is implicitly indicated by the reception of any control that arrives when write data is arrived at 783 and any control is indicated that does not require a read operation to be performed. In another embodiment, the retire control is indicated when write data is arrived at wires 783 and either no further operation is signaled on control signal lines 112 , or any control is indicated that does not require a read operation to be performed. The highlighted read operation in FIG. 12 shows the read control being transmitted on control signal lines 112 , which causes the memory core to be controlled by signals 710 and 715 . The characteristics of memory core 180 affect the time at which the read data is available and delivered via signals 775 , which are transmitted from the memory device on data signal lines 114 . The similar timing relationships for a read operation and a write operation, on control signal lines 112 and data signal lines 114 , allow back-to-back operations for read and write. This may be performed when the operations are to different devices (as in the case illustrated in FIGS. 3 , 7 and 8 ), but also when the operations are to the same device, due to the reordering that the retire control allows. In general, one control indicator is used to send the write data on data signal lines 114 . A retire control indicator is used to perform the operation at the memory core. Additional control indicators may be used to signal any other control information for the write, such as the addresses or masks, as long as all the control information arrives in time for the memory operation indicated by the retire control indicator. The ability to generally perform back-to-back write and read operations allows high utilization of data signal lines 114 providing a high performance memory system. The reordered writes of FIGS. 11 , 12 , 13 , and 14 indicate that a loss of coherency may occur if the data read is from the same location as one of the writes that has been delayed. The structure indicated relies on the originator of the memory operations to maintain coherency. This may be done in many ways known to one skilled in the art. In one instance, if the read location corresponds to one of the write locations, the read operation is delayed until the corresponding write operation is retired. In another instance, a copy of the write data is maintained by the originator and is merged with the read information, or replaces the read operation. FIG. 13 illustrates the use of a two-step write technique in the circuit of FIG. 11 (i.e., with one data buffer), in a situation where a read operation is delayed after a write stream, to allow the read operation to complete in the proper sequence with regard to the write operations requiring the column resources of memory device 100 . FIG. 13 shows that a small bubble can be inserted to allow the write “c” data to be retired. This is done by inserting a “no-operation” (no-op) operation in the command stream on control signal lines 112 . Write operation “d” is still reordered, and the bubble is smaller than it would be if not for the two step write. However, write “d” now has enough time to be stored in the retire buffer, again avoiding a conflict in the column resources of memory device 100 . Here again, write “d” is delayed to avoid the creation of a data bubble on interconnect 110 . However, a no-op is inserted to delay the read so as to avoid a conflict on the column resources of memory device 100 . By delaying the memory core's provision of the read data on the column resources, write “d” may be stored in the write data buffer, thus avoiding a conflict with the read operation. This allows a read operation to interrupt a stream of write operations without causing a conflict and without causing the data held in the write buffer to be overwritten. Those skilled in the art will appreciate that the “no-op” may be substituted with any operation that is not a read or write to memory device 100 , including read or write operations to other memory devices. FIG. 14 illustrates the use of a two-step write technique in the circuit of FIG. 11 (i.e., with one data buffer), in a situation where a read operation is issued with unstreamed write operations, to allow the read operation to complete in the proper sequence with regard to the write operations requiring the column resources of memory device 100 . FIG. 14 shows that the dilemma of having a second reordered write overwriting another write operation will be avoided if the writes are not streamed. If the originator schedules the writes with enough separation for one operation, as either “no operation” (or “no-op”) or a read, or a write to another device, then a read to this device can occur without any added delay, and without causing data to be overwritten in the one set of write data/mask buffers. Those skilled in the art will appreciate that a “no-op” can be substituted with any operation that does not involve a read or a write, such as a precharge operation. FIGS. 15 , 16 , 17 , and 18 illustrate an embodiment of a memory device according to the present invention in which the memory device also provides for coherency internally. This relieves the originator of the data and control signals (typically, a memory controller at the master) of having to keep track and maintain coherency in the operations the master unit had issued. The concept here is that portions of the data needed to satisfy a read operation may exist in one of several places (e.g., one or both of the write buffers, and/or in memory core 180 ). Thus, a mechanism could be provided to allow data to exist in any one of those places and still be accessible to a read operation, assuming such operations are allowed in the architecture of memory device 100 . This relieves the master unit (e.g., a memory controller) from having to keep track of where data is at any one time. FIG. 15 shows the structure of FIG. 9 with the addition of comparators to compare an incoming read address with the two buffered write addresses. If a memory read address matches the address of one or both buffered writes, the additional circuitry in the data path below allows the merging of the read data with either or both of the buffered write data. If there is no mask, the merge is a simple multiplexer operation and the read need not be performed at memory core 180 . In general, with a mask, the read does need to be performed and the data/mask combinations from the two buffered writes are used to update the read from memory core 180 to provide the latest information coherently. Control signals 700 are received from the transport block 120 . TCDS block 705 , read data operation unit 160 , and write operation unit 170 produce signals to control the memory core 180 . Signals 710 are the control signals for the memory core and are preferably edge based. Signals 715 are signals that are presented to memory core 180 for a duration of time, and usually have setup and hold requirements with respect to the transition times of signals 710 , and are produced by block 720 . For a read operation, control buffer 720 receives control signals directly from block TCDS 705 via signals 725 through multiplexer 730 , which is controlled by signal 735 . For a write operation, control buffer 720 receives 10 control signals from TCDS block 705 via write control buffer 740 , signals 745 , write control buffer 750 , signals 755 and multiplexer 730 . Write buffers 740 and 750 are controlled by signals 760 . For a write operation, signals 760 are timed to correspond to the arrival of the operation via signals 715 . The effect of write control buffer 740 and 750 is to delay the application of the operation control to the memory core. Another effect of write control buffers 740 and 750 is to allow storage of the write control information so that they may be passed on to the memory core for operation based on some later control indication, rather than just passing through on some fixed schedule. Other embodiments may use fewer or additional blocks to change the amount of the delay and storage. Read data buffer 765 receives read data on signals 770 from the memory core 180 , at times controlled by signal 771 . The data is passed on to a blender 19195 . Blender 19195 blends bits (or other quanta of data) to satisfy a read operation which may require data held in one of the write data buffers and/or memory core 180 . The requisite data is then passed on to transport block 120 via signals 775 . In another embodiment, read data buffer 765 is an amplifier capable of driving signals 19142 , without the need for timing signal 771 . In yet another embodiment, read data buffer 765 includes only interconnect. Other variations for read data operation unit 160 are possible, depending on specific drive and timing characteristics of the memory core. Write data buffer 19202 receives write data from transport block 120 on signals 781 and is controlled by signal 19201 . Write data buffer 19202 is an additional write data buffer, that is also controlled by signal 19201 so that it passes data through to write data buffer 19200 directly in some cases, but stores the data for later passing to write data buffer 19200 in other cases. The write data buffer 19200 receives write data from write data buffer 19202 via signals 19203 , under the control of signal 19201 , and presents the data to memory core 180 via signals 783 . In an analogous fashion, mask data is passed using signals 786 , 19208 , and 788 with mask data being stored in write mask buffers 19207 and 19205 . Mask data is used by memory core 180 to selectively write, or not write, parts of the data within the memory core. In another embodiment, no mask is used so that all the data is written unconditionally. By providing write data buffer 19200 (and write mask buffer 19205 ), memory device 100 allows write operations to be split into two operations, transport and retire. First, the write data (and mask) is transported to write data buffer 19200 (and write mask buffer 19205 ) using, for example, interconnect 110 . Upon receiving a retire command (in whatever form), the write data is communicated to memory core 180 . This allows write operations, which might otherwise be in contention for the column resources of memory device 100 , to complete at a time when no conflicts exist with regard to the now-available column resources. Additionally, the circuit of FIG. 15 permits data to be bypassed around memory core 180 in the case of a read requiring data held in write data buffers 19200 and 19202 (as indicated in part by write mask buffer 19205 and 19207 ). This is done by blender 19195 selecting signals 19203 and/or 19142 , either in whole or in part using signals 19208 to account for masking of data 19203 (enabled by the bit-slice architecture of blender 19195 ). Data held in write data buffer 19200 may also be blended by using signals 783 (and signals 788 to account for masking of that data). Those skilled in the art will appreciate how to adapt the coherency mechanisms from FIG. 15 into the circuitry of FIG. 11 where there is only one data buffer. FIG. 16 shows an embodiment for a blender circuit. FIG. 16 illustrates the circuitry for a single bit in detail. The multiplexer combines the compare hit control information and the mask bit to select either the upstream data bit or substitute the bit from the write data buffer. The upstream multiplexer selects between the read operation data bit and the oldest write buffer data. The downstream multiplexer selects between the upstream multiplexer and the youngest write buffer data. FIG. 16 illustrates a blender such as that shown in FIG. 15 as blender 19195 . The function of this circuit to provide the necessary data to satisfy a read operation that requires data that is held in one or both of the write buffers and also possibly in memory core 180 . The function performed by a blender of this type is to take data, portions of which may be masked, and portions of which may exist in various locations due to the architecture of a memory device implementing a 2-step write technique. FIG. 16 shows a blender 2000 which comprises a multiplexer 2020 and a multiplexer 2040 which select data from various sources to combine the data in satisfying the data requirements of the read operation. Multiplexer 2020 selects between data from read data buffer 765 and data from write data buffer 19200 . Information held in write mask buffer 19205 is combined with control signals from TCDS 705 by a circuit 2010 . Alternatively, this can be seen as the bit of write data being conditioned by the write mask bit held in the write mask buffer when the addresses compare. The results of this combination selects the input of multiplexer 2020 by indicating the selection on a signal line 2015 . The result of this selection is output on signal line 2025 , which is input to multiplexer 2040 . Multiplexer 2040 selects between the output of multiplexer 2020 and the output of write data buffer 19202 , again conditioned by the write mask information held in write mask buffer 19207 and address comparison. As shown in FIG. 16 , the write mask information held in write mask buffer 19207 is actually combined with control signals from TCDS 705 by a circuit 2021 , in the circuit shown in FIG. 16 (although numerous alternatives might easily be envisioned). The result of this operation causes multiplexer 2040 to select one of its inputs by indicating the desired selection on a signal line 2035 . The output on signal line 2045 forms a part of output 755 . As noted, blender 2000 represents only one bit-slice of a larger circuit. Thus, various portions of read data may come from various locations within memory device 100 , and may also be made to depend on the value of a write mask and the results of address comparison. FIG. 17 is a timing diagram when neither write control buffer matches the incoming read. This is indicated as a low level on read comparison signal 19216 . It can be seen that this timing diagram is substantially similar to the preceding timing diagrams (e.g., FIGS. 10 and 12 ), with the exception that signals relating to the bypass operations are shown. These include read comparison signal 19216 , which indicates a match of some or all of the data held in the write control buffers. Additionally, a read operation in such a system can be seen to require a small amount of extra time, allowing for the sequencing of comparison operations, and the potential blend of the read data and write buffers. FIG. 18 is a timing diagram showing the new signals and the blending performed to produce a coherent read data transmission. In this timing diagram, the read address matches the addresses of write data held in both write data buffer 19200 and write data buffer 19202 . This is indicated as a high level on read comparison signals 19216 . In this example, data from memory core 180 (exemplified by the results of read operation as read “e”), write “d” (held in write data buffer 19202 ), and write “c” (held in write data buffer 19200 ). IV. Variations on the Basic Two-Step Write Control Paradigm In general, one control indicator is used to send the write data on data signal lines 114 . A distinct retire control indicator is used to perform the operation at the memory core. Additional control indicators may be used to signal any other control information for the write, such as the addresses or masks, as long as all the control information arrives in time for the memory operation indicated by the retire control indicator. As previously described, a two-step write comprises a transport and a retire step. The transport step communicates the data and a portion of the address and mask information. Some or all of the transport information is buffered in the memory device. The retire step communicates the balance of the address and mask information and causes the data to be written to the memory core, using whatever information may have been buffered from the transport step. Thus, the mask information can be sent with the transport operation (or even before that point in time), with the retire operation, or as a separate operation, depending upon the system requirements. Indeed, these choices are applicable not only to write mask information, but to any of the control information that might need to be sent to memory device 100 . Thus, these operations may occur at any time before the write retires. In one embodiment, all of the address and mask information is transmitted with the transport step while the retire step indicates to the memory device that it is time for that buffered information to be written to the core. For example, all of the device, bank, and column addressing information plus the masking information can be sent in the transfer step, with the timing of the data transport associated with this step. In this embodiment, the retire step just provides memory core write timing. In another embodiment, only the device address is provided with the transport step that sends data to the memory device. In this embodiment the remaining information, such as the bank and column address, as well as the mask information, are sent when the data is to be written into the memory core. Other alternative embodiments are possible. In these embodiments, different elements of information are associated with either the transport or retire steps. In one embodiment, device, bank, and column addressing information are associated with the transport step, while masking information is associated with the retire step. This association allows maximum commonality of operation arguments, such as addressing information, to occur between read and write operations while, as a second order constraint, minimizing the buffering, since reads do not use masking information. In addition to the variations discussed above, the retire step can be either explicit or implicit. An explicit retire requires that an operation code or some means of coding that is discrete from the other operations in the packet, such as an independent bit, be provided for, and supplied to the memory device when it is time for the retire to occur. In addition to the means of indicating that the operation is to be performed there must also be a means to indicate which buffered information is to be retired. For example, this may be by means of a device address. However, other methods are possible, for example, each device could keep track of how many transports have occurred but have not been retired prior to a transport directed to it. A first-in-first-out (FIFO) policy might be implemented, in which case the device can do a retire at an appropriate time of its own choosing, without an explicit device address being needed. An implicit retire presumes that the memory device can determine when it can perform the write of the buffered information to the memory core without an explicit instruction to do so. There are many methods to do this. For example: If no transfer operation is directed to the memory device, it autonomously does a column write operation. When the memory device detects that an alternative operation is taking place that cannot require the column I/O resource then it performs the column write operation. If the retire is done autonomously, this eliminates the high level of control over resource consumption by the master unit (i.e., a memory controller). In some embodiments, it is desirable for the master unit to have a high level of control over resource consumption. This is because once the write information has been placed into the memory device, the memory device may proceed to use the column I/O resource at its discretion. If the master unit does not keep the column I/O resource busy, then the resource's usage will be triggered by the memory device, even if the master unit would prefer to use the column I/O resource before the resource goes idle again. If the retire is triggered by an alternative operation, this allows the controller to continue to exert control over the timing of the memory core write operation, without having to explicitly allocate control bandwidth to do so. This method may be implemented in several ways. In one embodiment, the memory device performs a retire operation whenever: control information is received, and the retire buffer is not empty (both control and data), and the control is read or write control and control information is either directed to a different column I/O path, or directed to the same column I/O path but is not a read operation the control is not read or write control Presuming that the transfer control information can arrive no faster than any column I/O path can perform a single transfer cycle it is impossible for a resource conflict to occur given the rules above. Another modification is varying the number of retire buffers employed. As noted, to avoid resource conflicts with the bidirectional column I/O bus in the core, the write operation may be divided into two (or more) steps. The write control information may include, for example, device, bank and column address and write mask. In one embodiment, the retire buffer stores write data and transport write control information until the retire command is issued and holds the write data valid long enough to meet the hold time requirements of the core interface. The actual write command signals to start the write operation are issued after the control logic receives the retire command. The depth of the retire buffers can be one or greater. A deeper retire buffer can eliminate loss due to certain read-write combinations that otherwise introduce performance bubbles in the pipeline, but do so at the cost of increased hardware and complexity. The method of the present invention is not intended to be limited by the preceding statements. A person of ordinary skill in the art will realize that different circuitry can be used and alterations can be made to the protocol of the present invention without departing from the spirit of the invention. Other equivalent or alternative protocols and apparatus according to the present invention will be apparent to those skilled in the art. For example, any number of retire buffers may be employed, allowing any amount of write data to be delayed, to account for resource conflicts at any point in the datapath of memory device 100 . These equivalents and alternatives are intended to be included within the scope of the present invention.

A memory component includes a memory core, a control transport block to receive a write command from external control lines, and a write control buffer to store the write command for a first time period after the write command is received at the transport block. A data buffer receives data from external data lines, the data to be stored in the memory core in response to the write command, wherein receipt of the data occurs based on a second time period that follows the first time period, such that receipt of the write command and the data are separated by a delay time that includes both the first time period and the second time period. A write mask buffer receives write masking information from an external write mask line. Receipt of the write command and the write masking information are separated by the delay time.

RELATED APPLICATION(S) [0001] This application claims the benefit of U.S. Provisional Application No. 60/881,967, filed on Jan. 23, 2007. The entire teachings of the above application(s) are incorporated herein by reference. BACKGROUND OF THE INVENTION [0002] In charge-domain signal-processing circuits, signals are represented as charge packets. These charge packets are stored, transferred from one storage location to another, and otherwise processed to carry out specific signal-processing functions. Charge packets are capable of representing analog quantities, with the charge-packet size in coulombs being proportional to the signal represented. Charge-domain operations such as charge-transfer are driven by ‘clock’ voltages, providing discrete-time processing. Thus, charge-domain circuits provide analog, discrete-time signal-processing capability. This capability is well-suited to performing analog-to-digital conversion using pipeline algorithms. [0003] Charge-domain circuits are implemented as charge-coupled devices (CCDs), as MOS bucket-brigade devices (BBDs), and as bipolar BBDs. The present invention pertains to MOS BBDs. [0004] Pipelined analog-to-digital converters (ADCs) are well-known in the general field of ADC design. They are widely used in applications in which high sample rates and high resolution must be combined. Pipelined ADCs implement the well-known successive-approximation analog-to-digital (A/D) conversion algorithm, in which progressively-refined estimates of an input signal are made at sequential times. In pipelined versions of this algorithm, one or several bits are resolved at each pipeline stage, the quantized estimate is subtracted from the signal, and the residue is propagated to the next pipeline stage for further processing. Pipelined ADCs have been implemented using a variety of circuit techniques, including switched-capacitor circuits and charge-domain circuits. The present invention pertains to charge-domain pipelined ADCs employing MOS BBDs. SUMMARY OF THE INVENTION [0005] In BBD-based pipelined ADCs, the gain between pipeline stages is nominally unity: that is, all net charge present in each stage ideally is transferred to the next stage. In practical BBD-based circuits, however, the charge-transfer gain is less than unity, resulting in errors in the A/D conversion process. Moreover, in all pipelined ADCs including those employing BBDs, mismatch of capacitors and of capacitor ratios causes such errors. [0006] The present invention corrects for errors in BBD-based pipelined ADCs due to both capacitor mismatch and to sub-unity charge-transfer gain. Circuits that implement this correction are compact and temperature-stable, and consume low power. [0007] In a preferred embodiment, a pipelined charge domain circuit using bucket brigade charge transfer comprises a first charge transfer circuit; a second charge transfer circuit; and a node coupled to the first charge transfer circuit and the second charge transfer circuit. A clocked capacitor is coupled to the node and to a clocked voltage. Furthermore, a conditionally-switched capacitor is also coupled to the node, with the conditionally-switched capacitor driven by a transition voltage. An adjustment circuit is provided for adjusting the transition voltage according to conditions detected within the pipelined charge domain circuit. BRIEF DESCRIPTION OF THE DRAWINGS [0008] The foregoing will be apparent from the following more particular description of example embodiments of the invention, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating embodiments of the present invention. [0009] FIG. 1 shows a simplified circuit diagram of a BBD charge-pipeline stage. [0010] FIG. 2 illustrates voltage waveforms associated with FIG. 1 . [0011] FIG. 3 shows a BBD charge-pipeline stage including conditional charge addition. [0012] FIG. 4 illustrates voltage waveforms associated with FIG. 3 . [0013] FIG. 5 shows a BBD charge-pipeline stage including conditional charge addition, with the added charge composed of two independent components. [0014] FIG. 6 shows a two-stage pipeline segment composed of stages like that of FIG. 3 . [0015] FIG. 7 shows a circuit diagram of a capacitor driver with an adjustable voltage transition. [0016] FIG. 8 illustrates voltage waveforms associated with FIG. 7 . [0017] FIG. 9 shows a circuit diagram of a replica-based circuit for determining a charge-transfer voltage-feedback coefficient. [0018] FIG. 10 illustrates voltage waveforms associated with FIG. 9 . [0019] FIG. 11 shows the adjustment circuit connected to a pipeline stage. [0020] FIG. 12 is a more detailed view of a differential BBD-charge pipeline stage. DETAILED DESCRIPTION OF THE INVENTION [0021] A description of example embodiments of the invention follows. [0022] The teachings of all patents, published applications and references cited herein are incorporated by reference in their entirety. [0023] In the following description, all circuits are discussed assuming electrons as the signal-charge carriers and NFETs for signal-charge transfer. Functionally equivalent circuits can be applied equally well using holes as charge carriers, by employing PFETs and reversed signal and control voltage polarities. In the discussion and figures, charge-transfer circuits are represented abstractly and the relevant behavioral aspects of these circuits are described, but in some instances, specific details of the operation of such circuits are understood by those of skill in the art and/or are not relevant to the invention claimed herein, and thus are not provided. The issue of sub-unity charge transfer gain is common to all known charge-transfer circuits. [0024] The basic principle of a BBD pipeline of the general type employed in a preferred embodiment of this invention is described with the aid of FIG. 1 , which depicts a single stage of such a pipeline. In this stage charge is stored on capacitor 5 , which is connected between storage node 2 and voltage V C1 . Charge enters the stage via charge-transfer circuit 1 , and later exits the stage via charge-transfer circuit 3 . Voltage V C1 is a digital clock signal which controls the timing of charge processing in the stage. Other digital clock signals, not shown, may be used to control the activity of the charge-transfer circuits. [0025] Operating waveforms of the pipeline stage are shown in FIG. 2 . At time to clock voltage V C1 has a positive value 25 . V 2 , the voltage of storage-node 2 in FIG. 1 , is also at a high initial voltage 21 . At t 1 negative charge begins to be transferred from the previous stage (to the left of FIG. 1 ) via charge-transfer circuit 1 into the stage shown. As this negative charge accumulates on capacitor 5 , V 2 falls to a more negative value. The voltage of node 2 settles to a relatively high value 22 A if a relatively small negative charge was transferred; with a larger charge transferred, node 2 settles to a more negative voltage 22 B. At time t 2 charge transfer into the stage is complete. The voltage of node 2 is related to the charge by the well-known expression Q=CV, where is the total capacitance of node 2 . In FIG. 1 , C is comprised of C 5 , the capacitance of capacitor 5 , plus any parasitic capacitance of node 2 ; such parasitic capacitance is usually small and is neglected in this discussion. [0026] Charge transfer out of the stage begins at time t 3 when clock voltage V C1 switches to a low state. Capacitor 5 couples this voltage transition to node 2 , driving V 2 low as well. Charge-transfer circuit 3 absorbs charge from capacitor 5 , limiting the negative excursion of node 2 , and eventually causing node 2 to settle to voltage 23 at t 4 . Voltage 23 is a characteristic of charge-transfer circuit 3 , and is independent of the amount of charge which had been stored on node 2 . Charge-transfer circuit 3 transfers the charge absorbed from capacitor 5 to node 4 which is part of the stage following the one shown. After t 4 charge transfer is complete. [0027] Finally, at time t 5 , clock voltage V C1 returns to its initial state (voltage 25 ). Its positive-going transition is coupled to node 2 by capacitor 5 , raising node 2 to voltage 24 . Neglecting parasitic capacitance, no charge flows onto or off of node 2 during this transition; the voltage change of V 2 is therefore equal to the voltage change of V C1 during the transition at t 5 . Since V 2 's value at the start of this transition, voltage 23 , is independent of charge processed, voltage 24 is likewise independent of charge processed. This transition completes the operating cycle; the resulting voltage 24 at node 2 is thus the initial voltage for the next cycle. Thus the initial voltage state of the stage is constant cycle-to-cycle, and voltage 21 =voltage 24 . Consequently the initial and final charge on node 2 are also equal, and the charge transferred out is equal to the charge transferred in. [0028] In summary: charge is transferred into the stage shown in FIG. 1 during t 1 -t 2 ; between times t 2 and t 3 it is temporarily stored on capacitor 5 , and is manifested as the value of V 2 ; during times t 3 -t 4 this charge is completely transferred to the next stage; at t 5 the stage returns to its initial state, ready again to receive incoming charge. Thus the basic stage shown acts as a shift register for analog charge packets. [0029] The foregoing description is somewhat idealized; it should be understood that practical circuits depart in many details from this description. Such departures include non-zero parasitic capacitance and imperfect charge transfer, for example. These effects, however, do not change the basic operating principles described above. Certain details of circuit operation, such as clocking of the charge-transfer circuits, are also omitted, as they are not pertinent to the present invention. [0030] In order to form a charge-domain ADC from a pipeline composed of stages similar to FIG. 1 , a minimum of two operations in addition to charge storage and shifting are required: charges must be compared to a reference value, typically another charge; and a reference charge must be conditionally added to the signal charge (this ‘addition’ may be of either sign). In a previous patent application by the same inventor entitled “Charge-Domain Pipelined Analog-to-Digital Converter” filed on Jan. 18, 2008 and given serial number 11/______, Attorney Docket Number 3575.1028-002, which itself claims priority an earlier filed provisional application of the same title filed on Jan. 19, 2007 and given provisional application Ser. No. 60/881,392, both of which are hereby incorporated by reference in their entirety, an ADC is disclosed which implements pipelined successive-approximation ADC algorithms using these operations. The present invention provides a way to improve the accuracy of charge-transfer and conditional-charge addition in such an ADC. For purposes of understanding the present invention, the charge-comparison aspects of ADC implementation are not important, and are not discussed further. Conditional charge addition is essential for such understanding, however, and is explained with reference to FIGS. 3 and 4 below. [0031] The basic principle employed for conditional charge addition is depicted in FIG. 3 , with operating waveforms shown in FIG. 4 . For the purposes of this discussion, a single-ended stage is shown. In practical ADC designs, differential operation is usually preferred; the present invention is applicable to both single-ended and differential pipeline circuits. More details of the implementation of a differential pipeline stage are shown and described in the aforementioned “Charge-Domain Pipelined Analog-to-Digital Converter” patent application. [0032] The pipeline stage shown in FIG. 3 retains all the elements shown in FIG. 1 . In addition, FIG. 3 includes two new elements: capacitor 6 (with value C 6 ) connected between charge-storage node 2 and voltage V QR1 ; and switch 7 connected between node 2 and voltage V P . Switch 7 is controlled by a periodic digital clock signal (identified as S 7 in FIG. 4 ). [0033] FIG. 4 shows the operating waveforms of the circuit of FIG. 3 . The initial conditions in FIG. 4 are similar to those in FIG. 2 : V C1 is at high voltage 45 and V 2 , the voltage of node 2 , is at high voltage 41 . In addition, V QR1 is at high voltage 47 , and switch 7 is in an off state, indicated by the low value of its control signal S 7 in FIG. 4 . As in FIG. 2 , charge is transferred into the stage between t 1 and t 2 , causing V 2 to fall in proportion to the incoming charge, settling at voltage 42 . The change in V 2 due to incoming charge is inversely proportional to the total capacitance of node 2 as explained above. In FIG. 3 (neglecting parasitic capacitance) this total capacitance is C=C 5 +C 6 . [0034] After the charge is transferred in, the new features of FIG. 3 come into play. At time t 3A voltage V QR1 conditionally switches from its high state 47 to low state 48 . This conditional transition of V QR1 is coupled via C 6 to node 2 where, because of capacitive division, it produces a similar but smaller voltage change. The voltage at node 2 changes to voltage 49 (dashed line) if V QR1 switches, and remains at voltage 42 (solid line) if it does not. [0035] At time t 3 , V C1 switches from high voltage 45 to low voltage 46 , instigating charge transfer out of the stage. As explained with reference to FIG. 2 , node 2 is driven to a lower voltage due to coupling via capacitor 5 . Charge-transfer circuit 3 removes charge from node 2 and transfers it to the next stage. By t 4 V 2 settles to voltage 43 which is independent of the charge previously on node 2 , and charge transfer out of the stage is complete. [0036] At t 5 both V C1 and V QR1 return to their initial high states (voltages 45 and 47 respectively). This transition is identical for V C1 in every clock cycle. V QR1 , however, may already be at its high voltage 47 , depending on whether or not it switched at t 3A . Thus the positive step coupled to node 2 at t 5 can have different values, depending on the state of V QR1 , resulting in a different final voltage. The added switch 7 in FIG. 3 is used to restore the voltage (and charge) on node 2 to a repeatable state regardless of the state of V QR1 at t 5 . Switch 7 is turned on, as indicated by the high state of its control signal S 7 , during t 5 -t 6 , thus establishing a repeatable voltage at node 2 to begin the next cycle, so voltage 44 =voltage 41 . With an ideal switch, voltage 44 =V P ; practical MOS switches introduce a small ‘pedestal’ so that voltage 44 ≠V P . This non-ideality is, however, repeatable cycle-to-cycle, so the voltage 44 =voltage 41 condition is still met in practical circuits. [0037] Unlike the case of FIG. 1 where the charge transferred into the stage was subsequently transferred out without alteration, the outgoing charge in the circuit of FIG. 3 differs in general from the incoming charge: [0000] Q OUT =Q IN +C 6 ΔV QR1 +Q CONST   Equation 1 [0000] where C 6 is the capacitance of capacitor 6 , ΔV QR1 is the change in V QR1 at t 3A , and Q CONST is given by: [0000] Q CONST =( C 5 +C 6 )(voltage 41−voltage 43)+ C 5 (voltage 46−voltage 45)  Equation 1A [0038] Q CONST is nominally a fixed charge, since voltages 41 , 43 , 45 , and 46 are all ideally constant. Departures from this ideal case, which constitute one source of charge-transfer imperfection, will be discussed below. [0039] As is apparent in FIG. 4 , ΔV QR1 is equal to (voltage 48 −voltage 47 ) if V QR1 switches, and is equal to zero if it does not. Note that both charge quantities C 6 ΔV QR1 and Q CONST can be made either positive or negative by appropriate choices of the various voltages. [0040] When the circuit of FIG. 3 is used to form one stage of a pipelined ADC, the quantity (voltage 48 −voltage 47 ) is made equal to a reference voltage; for convenience it will be called V R1 . Correspondingly, the quantity C 6 V R1 becomes a reference charge, since C 6 is fixed in a given instantiation. Thus the conditional choice of ΔV QR1 =V R1 or ΔV QR1 =0 at t 3A corresponds in Equation 1 to the conditional addition of a reference charge C 6 V R1 to the incoming charge packet Q IN . The circuit of FIG. 3 thus provides one of the two operations required for a charge-domain ADC implementation. [0041] Note that the exact position of time t 3A is not critical to the operation of the circuit of FIG. 3 . The conditional transition of V QR1 can occur at any time between t 0 and t 3 with no change in circuit performance; under some practicable conditions it may also occur in the t 3 -t 4 interval. [0042] In some ADC implementations it is desirable to provide more than one conditional charge addition in a single pipeline stage. An example of such a stage is shown in FIG. 5 . This circuit includes, in addition to the elements in FIG. 3 , additional capacitor 6 A and voltage source V QR2 . The operation of such a stage is identical to that of FIG. 3 , except that at t 3A each of the voltages V QR1 and V QR2 undergoes an independent conditional transition, of size V R1 and V R2 (or zero) respectively. The resulting charge transfer function of the stage is given by: [0000] Q OUT =Q IN +C 6 ΔV QR1 +C 6A ΔV QR2 +Q CONST2   Equation 2 [0000] where Q CONST2 is given by: [0000] Q CONST2 =( C 5 +C 6 +C 6A )(voltage 41−voltage 43)+ C 5 (voltage 46−voltage 45)  Equation 2A [0043] The same principle can be extended to any number of capacitors and V R values. For simplicity Equations 1 and 1A will be used as the basis for the following discussion. The principles described are equally applicable to circuits with more than one conditionally-switched capacitor, as in FIG. 5 . [0044] Two idealizations included in the discussion above are, in general, imperfectly realized in practical circuits: first, because of tolerances in manufacturing, conditionally-switched capacitors such as C 6 generally do not have precisely the intended values; second, the final voltage to which the floating diffusion 2 settles (voltage 43 in FIG. 4 , for example) is in general not perfectly independent of Q OUT . The effects of these non-idealities are considered in detail below, beginning with the dependence of voltage 43 on Q OUT . [0045] Considering a first-order (linear) dependence of voltage 43 upon Q OUT , the value of voltage 43 can be written v 43 =v 43N +kQ OUT , where v 43 is the actual value of voltage 43 , v 23N is the nominal value, and k is a coefficient embodying the linear dependence on Q OUT . Using this expression for voltage 43 in Equation 1A yields: [0000] Q CONST =  ( C 5 + C 6 )  ( voltage   41 - v 43  N - kQ OUT ) +  C 5  ( voltage   46 - voltage   45 ) =  ( C 5 + C 6 )  ( voltage   41 - v 43  N ) +  C 5  ( voltage   46 - voltage   45 ) - ( C 5 + C 6 )  kQ OUT =  Q CC - ( C 5 + C 6 )  kQ OUT Equation   3 [0000] where Q CC is the Q OUT -independent (i.e., constant) component of Q CONST . Replacing Q CONST in Equation 1 with the expression given by Equation 3, we obtain: [0000] Q OUT =Q IN +C 6 ΔV QR1 +Q CC −( C 5 +C 6 ) kQ OUT   Equation 4 [0046] Turning now to the fabrication errors in C 6 , we can write C 6 =C 6N +C 6E , where C 6N is the nominal value of C 6 , and C 6E is the deviation from nominal. Substituting this expression into Equation 4 yields: [0000] Q OUT =Q IN +C 6N ΔV QR1 +C 6E ΔV QR1 +Q CC −( C 5 +C 6 ) kQ OUT   Equation 5 [0047] In fractional terms, the errors expressed in Equation 5 are C 6E /C 6N and (C 5 +C 6 )k, both of which are dimensionless quantities. In practical designs these fractional errors are small (i.e., <<1). Thus we can find a practically-useful approximation to Equation 5 by replacing Q OUT in the last term with the full expression given by Equation 5, and then omitting second-order error effects (i.e., terms including squares or products of the fractional errors). Defining ε=(C 5 +C 6 )k and carrying out this procedure, we obtain: [0000] Q OUT =Q IN (1−ε)+ C 6N ΔV QR1 (1−ε)+ Q CC (1−ε)+ C 6E ΔV QR1   Equation 6 [0048] Comparing this expression to the idealized expression of Equation 1, it is apparent that the quantity (1ε) is an effective charge-transfer gain; ε is the amount by which that gain falls short of unity. The term C 6E ΔV QR1 embodies the effect of fabrication error in C 6 . [0049] A pipelined charge-domain ADC is composed of multiple stages like that of FIG. 3 , in which reference charges are conditionally added and subsequently transferred down the pipeline. (As mentioned above, some architectures employ multiple conditional charges per stage.) Equation 6 expresses the output charge of each such stage in terms of that stage's input charge and its conditional capacitor switching. At any stage of the pipeline, the input charge is the sum of the signal-charge input to the pipeline and the cumulative changes due to up-stream pipeline stages according to Equation 6. [0050] Consider for example the two-stage pipeline segment shown in FIG. 6 , which is composed of stages like that in FIG. 3 . The two stages, 61 and 62 , each consist of a storage node ( 67 and 68 respectively), a charge-transfer circuit ( 65 and 66 respectively), a conditionally-switched capacitor ( 63 and 64 respectively), a clocked capacitor ( 601 and 602 ), and a precharge switch V P . The input charge to the pipeline segment, Q PIN , is supplied to storage node 67 of stage 61 as indicated. The output of this pipeline segment (which is the output charge of stage 62 ) appears at node 69 . The conditionally-switched voltages driving capacitors 63 and 64 are V QR1 and V QR2 respectively. They can each independently be switched, with a step-size of 0 or V R1 and 0 or V R2 respectively, where V R1 and V R2 are reference voltages. [0051] Such a pipeline operates in two-phases: alternating stages operate on alternating half-cycles of the clock. In the circuit of FIG. 6 , for example, charge is transferred into stage 61 and out of stage 62 on the first half-cycle, and is transferred out of stage 61 and into stage 62 on the second half-cycle. Details of this clocking method are not germane to the subject of the present invention, and are not treated further. [0052] The input charge to stage 62 in FIG. 6 is the output charge from stage 61 . Thus, with the input charge to stage 61 equal to Q PIN , the output charge from stage 62 can be derived by applying Equation 6 twice: [0000] Q OUT   62 =  Q IN   62  ( 1 - ɛ ) + C 64   N  Δ   V QR   2  ( 1 - ɛ ) + Q CC  ( 1 - ɛ ) +  C 64   E  Δ   V QR   2 =  [ Q PIN  ( 1 - ɛ ) + C 63   N  Δ   V QR   1  ( 1 - ɛ ) + Q CC  ( 1 - ɛ ) +  C 63   E  Δ   V QR   1 ]  ( 1 - ɛ ) + C 64   N  Δ   V QR   2  ( 1 - ɛ ) +  Q CC  ( 1 - ɛ ) + C 64   E  Δ   V QR   2 =  Q PIN  ( 1 - ɛ ) 2 + C 63   N  Δ   V QR   1  ( 1 - ɛ ) 2 +  C 64   N  Δ   V QR   2  ( 1 - ɛ ) + C 63   E  Δ   V QR   1  ( 1 - ɛ ) +  C 64   E  Δ   V QR   2 + [ ( 1 - ɛ ) 2 + ( 1 - ɛ ) ]  Q CC Equation   7 [0053] This expression can be simplified by omitting second-order error terms as was done above, giving: [0000] Q OUT   62 = Q PIN  ( 1 - 2  ɛ ) + C 63  N  Δ   V QR   1  ( 1 - 2  ɛ ) + C 64  N  Δ   V QR   2  ( 1 - ɛ ) + C 63  E  Δ   V QR   1 + C 64  E  Δ   V QR   2 + ( 2 - 3  ɛ )  Q CC Equation   8 [0054] Equation 8 shows the cumulative effect of charge-transfer gain and capacitor errors in a two-stage pipeline. The same analysis can be extended to multiple stages and to multiple conditionally-switched capacitors per stage. [0055] In order for a pipelined charge-domain ADC to produce linear results, it is essential that the conditionally-added charges from each stage appear at the end of the ADC pipeline with a specific ratio. In the Equation 8 the (non-zero) values of the conditionally-added charges are nominally C 63N V R1 and C 64N V R2 in the first and second stages respectively. According to equation 8 then, the conditionally-added charge values, as they appear at the pipeline output, are: [0000] [C 63N V R1 (1−2ε)+C 63E V R1 ] from the first stage, and [C 64N V R2 (1−ε)+C 64E V R2 ] from the second stage. [0056] Thus the ADC linearity requirement can be expressed as: [0000] [ C 63N V R1 (1−2ε)+ C 63E V R1 ]/[C 64N V R2 (1−ε)+ C 64E V R2 ]=K   Equation 9 [0000] where K is the intended ratio. In an ideal pipeline segment, in which the charge-transfer and capacitor errors are zero, Equation 9 is simplified to: [0000] ( C 63N V R1 )/( C 64N V R2 )= K   Equation 10 [0057] The effects of non-zero gain error ε and capacitor errors such as C 63E are evident when Equation 9 is compared to Equation 10. [0058] One aspect of the present invention provides a way to satisfy Equation 9 when these errors have non-zero values. This can consist of providing an adjustment to the reference voltages V R1 and V R2 . The nominal capacitance values C 63N and C 64N and the reference voltages V R1 and V R2 are chosen to satisfy Equation 10; then independently adjustable voltages V A1 and V A2 are added to V R1 and V R2 . With this change, and again omitting second-order error terms, the upper and lower terms in the ratio of Equation 9 become: [0000] [ C 63  N  V R   1  ( 1 - 2  ɛ ) + C 63  E  V R   1 ] -> [ C 63  N  ( V R   1 + V A   1 )  ( 1 - 2  ɛ ) + C 63  E  V R   1 ] =   [ C 63  N  V R   1  ( 1 - ɛ ) - ɛ   C 63  N  V R   1 + C 63  E  V R   1 + C 63  N  V A   1 ]   and  [ C 64  N  V R   2  ( 1 - ɛ ) + C 64  E  V R   2 ] -> [ C 64  N  ( V R   2 + V A   2 )  ( 1 - ɛ ) + C 64  E  V R   2 ] =   [ C 64  N  V R   2  ( 1 - ɛ ) + C 64  E  V R   2 + C 64  N  V A   2 ) ] [0059] The added voltages are now adjusted to force the ratio of the adjusted bracketed terms to equal K. For example, setting: [0000] V A1 =[ε−( C 63E /C 63N )] V R1   Equation 11A [0000] and [0000] V A2 =−( C 64E /C 64N ) V R2   Equation 11B [0000] results in the desired ratio. With this solution, V A2 is adjusted to correct for the error of capacitor 64 and V A1 is adjusted to compensate both for the error of capacitor 63 and for the charge-transfer gain ε. [0060] An alternative adjustment is: [0000] V A1 =( C 63E /C 63N ) V R1   Equation 12A [0000] and [0000] V A2 =[−ε−( C 64E /C 64N )] V R2   Equation 12B [0000] which also results in the desired ratio. With this solution, V A1 is adjusted to correct for the error of capacitor 63 and V A2 is adjusted to compensate both for the error of capacitor 63 and for the charge-transfer gain F. Both solutions 11A/B and 12A/B are useful. Any linear combination of these solutions can be used with the same result. [0061] This same adjustment principle can be applied in a pipeline with any number of stages. It can also be applied in an ADC design with more than one conditionally-added charge per stage (as in the example of FIG. 5 ). In these cases, a separate adjustment voltage (V A ) is applied to the reference voltage for each conditionally-switched capacitor. With the adjustment method of Equation 12A/B, for example, each such adjustment corrects for the combination of that individual capacitor's error and the total charge-transfer errors of all previous stages. In some designs, the charge-transfer error is not identical from stage to stage, but this adjustment method intrinsically accommodates such variation. [0062] In addition, the same adjustment principle can be applied to a differential pipeline stage; in such an instance it may be preferable to generate a single adjustment voltage V A that is shared between the two members of the differential circuit. [0063] Recall from the discussion of FIGS. 3 and 4 that the conditional voltage transition ΔV QR1 which produces the conditional charge addition C 6 ΔV QR1 results from switching V QR1 between two fixed voltages ( 47 and 48 in FIG. 4 ). This voltage difference constitutes the reference voltage V R . A practical way of adding the adjustment voltage V A to V R is to insert a small adjustable voltage in series with either voltage 47 or voltage 48 . One realistic implementation of the driver and adjustable voltage source, 8 and 9 in FIG. 11 , is shown in FIG. 7 . [0064] FIG. 11 shows an example of a pipeline stage like that of FIG. 1 with such an adjustment voltage added. Pipeline elements 1 , 2 , 3 , 5 , and 6 are equivalent to those in FIG. 1 . The added elements are a driver 8 for conditionally-switched capacitor 6 , and an adjustable voltage source 9 . The output of driver 8 switches between supplied voltage V 8 and the voltage at node 10 in response to a digital control signal S QR1 , thus providing the required conditional voltage transition. Thus V H and voltage 10 provide the voltages identified as 47 and 48 respectively in FIG. 4 . Adjustable voltage source 9 adjusts the low voltage supplied to capacitor 6 as described above. [0065] FIG. 12 shows a differential pipeline with similar function. Each member of the differential pair of pipeline nodes, 2 and 122 , is provided with a conditionally-switched capacitor, 6 and 126 respectively. The voltage transitions driving capacitors 6 and 126 are provided by drivers 8 and 128 , switching between V H and the voltages of nodes 10 and 130 , in response to digital control signals S QR1A and S QR1B , respectively. The voltages of nodes 10 and 130 are supplied by adjustable voltage sources 9 and 129 respectively. Nodes 10 and 130 may be connected to form a single node, and supplied by a single adjustable source such as 9 . [0066] FIG. 7 shows a CMOS inverter consisting of PFET 71 and NFET 72 , supplied by fixed voltages V H and V L . The NFET is connected to V L via resistor 73 at node 75 . An adjustable current 74 is also connected to node 75 . The inverter is driven by a logic signal S QR1 , and its output constitutes the voltage signal V QR1 shown in FIG. 3 . [0067] FIG. 8 shows operating waveforms for the circuit of FIG. 7 . At time to logic signal S QR1 is at a low state, turning PFET 71 on and NFET 72 off. Voltage V QR1 is at an initial high value which is equal to V H . At time t 3A S QR1 switches to a high logic state, turning FET 71 off and FET 72 on. FET 72 thus connects the output V QR1 to node 75 . If the adjustable current 74 is set to zero, then the series combination of FET 72 and resistor 73 charges V QR1 towards V L , as indicated by voltage curve 81 in FIG. 8 . Since the load on this circuit consists only of a capacitor (capacitor 6 in FIG. 3 ), there is no DC current through FET 72 or resistor 73 , so V QR1 eventually settles to V L . Thus the voltage transition of V QR1 is V L -V H . This quantity constitutes the unadjusted reference voltage V R . [0068] If the current source 74 is adjusted to a non-zero value I A , then the initial value of node 75 is V L +V A =V L +I A R 73 , where R 73 is the value of resistor 73 . (Note that FET 72 is initially off, so no current other than I A initially flows into resistor 73 .) When S QR1 changes state, then FET 72 turns on and connects the load capacitor to node 75 , causing V QR1 to charge downward along curve 82 . At the end of this transition, current through FET 72 falls to zero and V QR1 settles to final voltage V L +V A . Thus the voltage transition of V QR1 is V L +V A −V H =V R +V A . Adjustable current source 74 , which is easily realizable in a practical circuit, thus provides for adjusting the size of the transition in V QR1 , as required. A similar circuit in which the resistor is placed in the source of PFET 71 instead of NFET 72 is equally practical. These circuits provide the necessary adjustment of V R with low power and small circuit area consumption. [0069] As discussed in connection with Equations 11A and 12B, the required V A values have two components: one which corrects for a capacitor error and one which corrects for charge-transfer gain error. In the circuit of FIG. 7 , the current source 74 can be made to consist of two independent sources in parallel, each controlled independently to correct for one of the errors. The combined currents sum to develop the composite V A value. [0070] The capacitor-error component corrected by V A can be expected to be temperature-invariant because it is due primarily to geometric variation between capacitors, which occurs during circuit fabrication but does not generally change thereafter. Thus an adjustment voltage V A which tracks V R provides a temperature-stable adjustment. Creating a component of V A which tracks V R over temperature using circuits similar to FIG. 7 is straightforward in a conventional CMOS process. The value of this adjustment voltage can be set by a calibration process carried out during manufacturing test or upon powering-up the circuit, for example. [0071] The second V A component corrects for charge-transfer gain error. This error depends on details of the charge-transfer circuits employed, and depends in general on both fabrication-process variation and on operating temperature. Known BBD charge-transfer circuits include both conventional (passive) ones and ones employing active circuitry, such as those described in a previous patent application by the same inventor entitled “Boosted Charge-Transfer Pipeline”, U.S. patent application Ser. No. 11/807,914, filed May 30, 2007, which is hereby incorporated by reference in its entirety. These charge-transfer circuits exhibit both dynamic and static components of charge-transfer gain error. One aspect of the present invention provides for generating an adjustment-voltage component which tracks the static component of charge-transfer error. [0072] In the discussion leading to Equations 3-6, the charge-transfer gain error was formulated in terms of the variation of charge-transfer-circuit input voltage with the amount of charge transferred. In that discussion the final value of the voltage v 43 at the input of the charge-transfer circuit was given as v 43 =v 43N +kQ OUT , with v 23N the nominal value, and k a coefficient embodying the linear dependence on Q OUT . This formulation encompasses both dyanmic dependence of v 43 on Q OUT (due to incomplete settling) and static dependence. For the following discussion, it will be assumed that the dynamic effect is negligible, and the coefficient k reflects only static dependence. [0073] It is known that the primary mechanism causing this static dependence is a voltage-feedback effect by which a voltage change at the charge-transfer circuit output causes its input voltage to change. As shown in FIG. 2 , the output voltage of a charge transfer circuit is a function of the output charge; thus the causation giving rise to the coefficient k is: [0000] output charge→output voltage change→input voltage change [0074] If we denote the coefficient relating output voltage change to input voltage change: [0000] β= dv IN /dV OUT [0000] then the coefficient k relating output charge change to input voltage change is: [0000] k=dv IN /dQ OUT =( dv IN /dv OUT )( dv OUT /dQ OUT )=β dv OUT /dQ OUT [0075] But d(v OUT )/d(Q OUT ) is simply the inverse of the capacitance at the charge-transfer circuit output node (which is equal to the node capacitance of the next pipeline stage). Defining that capacitance as C OUT , we then have: [0000] k=β/C OUT [0076] Referring again to FIGS. 3 and 4 , we recall that the charge-transfer error ε was given, in terms of k and the storage-node capacitance C 5 +C 6 , as ε=(C 5 +C 6 )k, leading to the expression: [0000] ε=( C 5 +C 6 ) k= ( C 5 +C 6 )β/ C OUT =β[( C 5 +C 6 )/ C OUT ]  Equation 13 [0077] Thus the charge-transfer gain error ε depends on the voltage-feedback coefficient β of the charge-transfer circuit and a ratio of pipeline node capacitances. Since the pipeline node-capacitance ratios are known by design within small tolerances (discussed above), the gain error value ε can be derived from a determination of the voltage-feedback coefficient β. [0078] FIG. 9 shows a circuit which senses the voltage-feedback coefficient β. It consists of a charge-transfer circuit 91 with input node 92 and output node 93 , a voltage source 95 connected to node 93 , and a current source 94 connected to node 92 . Charge-transfer circuit 91 is a replica of the charge-transfer circuits employed in the actual charge pipeline. Current source 94 is configured to sink from node 92 a small current which is typical of current levels near the end of the charge-transfer process described above. Voltage source 95 provides a voltage at node 93 which is in the range normally occurring at the output of the charge-transfer circuit at the end of the charge transfer process (such as voltage 42 in FIG. 4 ). Thus the charge-transfer circuit in FIG. 9 is biased in a static condition essentially like its instantaneous condition near the end of the normal (clocked) charge-transfer process. [0079] FIG. 10 shows the voltages of the two nodes in FIG. 9 . V 93 , the voltage of node 93 , is driven cyclically by voltage source 95 between two levels 101 and 102 differing by ΔV 93 . Due to the voltage-feedback effect discussed above, the input voltage of the charge-transfer circuit (i.e., the voltage V 92 at node 92 ) responds by changing between two levels 103 and 104 , with difference ΔV 92 . By the definition above, these voltage changes are related as: [0000] ΔV 92 =βΔV 93 [0080] Thus for a known (fixed) value of the drive voltage change ΔV 93 , ΔV 92 provides a direct measure of β. Using the known-by-design values of (C 5 +C 6 )/C OUT and the reference voltage, the appropriate adjustment voltage (V A2 in Equation 12B, for example) can be generated using known circuit techniques. [0081] The voltage change ΔV 92 can be converted to a DC voltage using phase-sensitive detection, since the alternating drive voltage V 93 is available as a reference. The frequency of this alternating voltage is not critical, and need not be as high as the sample rate of the charge pipeline, as the parameter being sensed changes only slowly (primarily due to chip temperature changes). Because of the low current at node 92 , settling of V 92 in response to each V 93 transition is relatively slow, so the operating frequency of this circuit must be limited in order to obtain a valid settled value for ΔV 92 . [0082] Alternatively, two circuits like that of FIG. 9 , with differing DC voltages supplied by the output-node voltage sources, thus producing two different input-node voltages, can be used to directly generate a static (DC) value of ΔV 92 . The alternating-voltage method described above is generally more accurate, however, since ΔV 92 is quite small (typically only a few mV or tens of mV). [0083] In a practical charge pipeline, the charge-transfer circuits may not be of identical design at all stages. The β-sensing circuitry just described consumes very little power, and can practically be reproduced for each charge-transfer circuit design employed. [0084] The circuitry described provides a correction voltage based on a charge-transfer circuit which is a replica of the charge transfer circuits in the pipeline. Such a replica-based method provides very good tracking over operating conditions, but typically has small initial mismatches. Such initial mismatches can be removed in a calibration operation, at manufacturing test or during circuit power-up for example. After the calibration, the replica-based circuit provides tracking of subsequent changes in operating conditions, including temperature and supply voltage. [0085] Such an initial calibration step also (simultaneously) provides correction for any dynamic component of charge-transfer gain error which is present under the calibration conditions. Any change of this dynamic error with operating-condition changes (especially temperature) after calibration, however, is not corrected by the techniques of this invention. [0086] While this invention has been particularly shown and described with references to example embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims.

A technique for correcting errors in Bucket Brigade Device (BBD)-based pipelined devices, such as Analog-to Digital Converters (ADCs). The gain between pipeline stages is desired to be a specific amount, such as unity: that is, all net charge present in each stage ideally is transferred to the next stage. In practical BBD-based circuits, however, the charge-transfer gain is less than ideal, resulting in errors. The approach described herein provides analog correction of such errors due to both capacitor mismatch and to sub-unity charge-transfer gain. In certain embodiments the adjustment circuit may use an adjustable current source and Field Effect Transistor to introduce the correction. In still other embodiments, the adjustment circuit may determine a voltage-feedback coefficient.

BACKGROUND AND SUMMARY OF THE INVENTION The present invention relates to bedding used in correctional institutions, hospitals and the like, and, more particularly, to foam filled, plastic covered bedding for use as mattresses and pillows. Various governmental and private institutions, such as jails, prisons, and hospitals, need to provide bedding to large numbers of persons simultaneously. This bedding typically must include a mattress and a pillow in order to provide proper support for the human body and head during rest. Previously, a wide variety of materials and assemblies have been used for this purpose, typically involving a fabric covering for the mattress and a fabric pillow case. The mattress and pillow have been formed from a variety of materials, but also typically involving a fabric covering sewn together at its seams. Such arrangements have been satisfactory for many purposes, but do have certain disadvantages. When it is necessary to routinely clean and sanitize the bedding, the mattress cover and pillow case must be removed, separately washed, dried and then separately reinstalled. Since this process may take some time, days even in large institutions, additional mattress covers and pillow cases are typically installed during the interim, and the former items are cyclically placed into storage/inventory until the next cleaning. Since the fabrics used are often porous, if a fluid is spilled onto or applied to the mattress cover or pillow case, the fluid may penetrate to the underlying mattress or pillow, and that item may additionally need to be cleaned, sanitized (if possible) or replaced entirely, often at relatively high cost. Thus, the cyclical cleaning process can be labor intensive, slow and expensive, requiring a relatively high volume of components and stored inventory. Also, some prior bedding materials have been particularly susceptible to interior contamination from insects, fluid (blood, water, oil and the like) borne bacteria and virus and/or destructive fluids. Various methods of reducing that risk have been suggested, but often involving expensive and/or elaborate material, construction arrangements and ventilation methods. Further, since over time and continual use bedding does tend to wear out or become irreparably contaminated or destroyed, many institutions must keep a replacement supply of bedding and bedding coverings in inventory as well. Unfortunately, many prior bedding arrangements are relatively expensive and thick, requiring considerable storage space for this inventory, and bulky, being more difficult to handle. Moreover, bedding used in correctional institutions is faced with additional, special difficulties. Previously, some inmates have modified pillows and similar severable bedding elements into hard, blunt weapons capable of killing and/or as shields and like accessories to violent action. Also, bedding seams have been opened by severing the threads which hold the fabric together in order to hide contraband inside the bedding. The seams can then be lightly closed by tape and other means to render the contraband easily accessible to the inmate, but not easily or quickly detectable by guards and facility inspectors. In addition, the bedding material itself and/or coverings for that bedding, such as seam thread and padding, has been removed by the inmates to make contraband items or weapons. It has also been found that some inmates tend to abuse the bedding to a much greater degree than other users normally would, thereby significantly decreasing its usable life. For example, penetration of the bedding by the inmate's bodily fluids inadvertently or otherwise can cause unsanitary conditions and destructive rot to exist inside of the bedding, as well as increase the required instances of cleaning for the bedding exterior. Nonetheless, when such bedding is removed for security or disciplinary reasons or deteriorates to an unserviceable state, even allegedly at the inmate's own hand, the denial of proper bedding has been the source of expensive and time consuming litigation against the correctional facility by the inmate, regardless of the outcome of the litigation. In other applications, articles have been suggested which employ an integrated mattress and pillow, particularly for recreational use on or about water, which are formed of compressible foam or a heat sealed bladder. In the former structures, however, air ventilation within the article and about the foam with fluid restriction at the same time has been lacking. In the latter structures, incidental punctures have rendered the article unusable. Accordingly, it is an object of the present invention to provide an improved bedding arrangement. Other objects include the provision of a bedding arrangement that is: a. durable and relatively inexpensive to manufacture and maintain; b. convenient to clean, sanitize and inventory; c. less susceptible to misuse and abuse; d. comfortable and properly supportive of the user during rest; and e. more resistant to contamination. These and other objects of the present invention are attained by the provision of a bedding arrangement having a compressible foam mattress pad and compressible foam pillow pad integrated as a single bedding unit within a fluid resistant or impermeable cover whose seams are heat sealed together. Air ventilation through the cover and about the interior foam is permitted by a vent that restricts insect, article and fluid passage through the vent. By using foam of different densities and/or composition, optimum performance characteristics in terms of comfort and support can be obtained separately for the mattress portion and the pillow portion. By mounting two pillow pads within the cover, the bedding arrangement can be made reversible. Other objects, advantages and novel features of the present invention will now be readily apparent to those of ordinary skill in the art from the following drawings and description of preferred embodiments. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a top plan view of a bedding arrangement according to the present invention. FIG. 2 shows a side view of the bedding arrangement of FIG. 1 . FIG. 3 shows a pillow end view of the bedding arrangement of FIG. 1 . FIG. 4 shows an enlarged view of the vent portion of the bedding arrangement of FIG. 1 . FIG. 5 shows an enlarged, cross sectional side view of a portion of the bedding arrangement of FIG. 1 with the vent components shown additionally exploded for ease of viewing, the enlargement not being exactly to scale of the enlargement of FIG. 4 . DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS FIG. 1 shows a preferred embodiment of a bedding arrangement 10 according to the teachings of the present invention. Bedding arrangement 10 includes a mattress portion 20 and a pillow portion 40 . Mattress portion 20 is formed from padding material 22 and sized into a body supporting dimension. Pillow portion 40 is formed from padding material 42 and sized into a head supporting portion. In the embodiment shown in the drawings, two pillow portions 40 are included on either side of one end of mattress portions 20 . Preferably, these pillow portions are in fixed positions, with the end of mattress portion 20 sandwiched therebetween. However, it will be understood that if desirable in a given application, only a single pillow portion 40 may be used. An advantage of using two such pillow portions as shown is that it permits bedding reversibility, as will be understood more fully from the discussion below. In preferred embodiments, the padding material for both portions is compressible urethane foam. It is often especially desirable to have different density or compressibility characteristics for padding 22 and padding 42 in order to optimize the comfort and support levels in each portion of the bedding arrangement for a particular application. For example, 18045 urethane foam could be used for padding material 22 with 18028 urethane foam used for padding material 42 . Alternatively, densified polyester batting, silicone foam, neoprene foam, cotton batting or the like or combinations of those materials, or even a combination of foam with a polyester core could be used as the padding materials in the present invention, according to the desired results in a given application. The dimensions of bedding arrangement 10 can also be as desired in a given application, although in preferred embodiments the overall length and width is recommended to be 75 inches and 25 inches, respectively, with the thickness of mattress portion 20 being 3 inches and the thickness of each pillow portion 40 being 2 inches. Similarly, recommended pillow dimensions are 12.25 inches long by 25 inches wide. It will be understood that the proportions of these features in the drawings are only very roughly drawn to this scale as the exact dimensions are not critical to the applicability and function of the present invention. Covering 60 surrounds mattress portion 20 and pillow portions 40 simultaneously and integrates them into a single unit that is inseparable under normal use. Covering 60 is preferably formed from a sheet plastic material such as Dartex P338 Cromarty polyurethane material, commercially sold by Penn Nyla of Nottingham, England. In other applications, urethane based materials, such as nylon 6 warp knitted fabric with a polyurethane transfer coating, or vinyl based or vinyl coated materials, or PVC or polyolefin laminated or coated fabrics or other heat sealable covering materials with antibacterial, antifungal and fluid penetration resistant characteristics can be employed. The seams of covering 60 are preferably heat sealed in a convention manner by radio frequency, thermal or sonic welding or sealed by chemical, adhesive or cement bonding, according to the specific materials used for covering 60 in a given application. In order to allow internal ventilation between the interior of bedding arrangement 10 and the exterior environment, a vent arrangement 80 is provided at one end of mattress portion 20 , preferably adjacent pillow portions 40 . In especially preferred embodiments, that vent arrangement includes a plurality of stacked discs which permit air to readily flow into and out of covering 60 , but restrict the flow of fluids, such as water and oil, articles, debris and insects into the interior of the bedding arrangement. The materials used for these discs are also preferably puncture resistant when used in stacked relation. One such suitable vent arrangement would include an exteriorly exposed vinyl or urethane coated polyester screen disc 82 , backed by a hydrophobic/oleophobic miro porous membrane disc 84 , backed by an interiorly exposed vinyl or urethane coated polyester screen disc 86 , backed by a polyurethane adhesive washer 88 . More specifically, Textilene material commercially sold by Unitex of Central Falls, R.I. has been found suitable for discs 82 and 86 in preferred embodiments. Versipor membrane material commercially sold by Pall Specialty Materials of Port Washington, N.Y. has been found suitable for disc 84 in preferred embodiments. Polyurethane film washers commercially sold by Bemis Asso., Inc. of Shirly, Mass. have been found suitable for washer 88 in preferred embodiments. Other materials having, alone or in combination, a breathable barrier while blocking undesirable intrusions can be used in specific applications. In preferred embodiments, the stack of discs in vent arrangement 80 is aligned with and closes an opening 62 in cover 60 . For example, when opening 62 is formed to be 1 inch in diameter, the stack of discs is preferably formed to be 1.25 inch in diameter and heat sealed about the outermost 0.25 inch of its diameter against the portion of cover 60 adjacent opening 62 . Thus, vent arrangement 80 would be securely positioned onto cover 60 and permit ventilation only through the discs and not about the disc peripheries. In function, disc 82 , being directly exposed to the exterior environment, includes screen openings large enough to allow air to pass freely therethrough, but forms a primary barrier to resist larger insects, articles, debris and puncture. Disc 82 also serves to positively locate and at least partially shield disc 84 from damage. Disc 84 is, for example, micro porous to allow air to flow through it in either direction, but resists the flow of fluids, such as water, blood, oil and the like, at least in a direction toward the interior of cover 60 . Disc 84 also serves to resist the entry of smaller insects which might pass through disc 82 . Interiorly positioned disc 86 includes screen openings large enough to allow air to pass freely therethrough, but forms a primary barrier to resist abrasive damage to disc 84 from contact with the interior materials of the bedding arrangement. Further, in stacked relation with disc 82 , this interior disc also provides resistance to puncture damage from the exterior environment. As will now be readily understood, the present invention provides numerous advantages over the prior art. Using the example of a correctional institution application, bedding arrangement 10 of the present invention is a comfortable, fully supportive, one piece unit with no separable pillow to be misused, no seams to unravel, and no thread to remove. Incisions to the interior are resisted, but readily detectable if they do occur, such that hidden contraband can be more easily located. By appropriate selection of fluid resistant material for cover 60 , the entire exterior of the bedding arrangement can be easily cleaned and disinfected and the interior padding material only minimally exposed to contamination and deterioration. Mounting two pillow portions 40 on opposite sides of mattress portion 20 allows the useful life of the overall unit to be extended merely by reversing the unit, flipping the bedding arrangement over to use the other side. The present invention thus provides a longer unit life cycle with reduced cycle costs once procured. Additionally, since only a single element is needed with pillow/mattress integration, the procurement costs themselves are reduced. Further, the slim, one piece structure of the present invention minimizes handling costs and inventory space needed for storage and replacement units. In alternative embodiments customized for particular applications, covering 60 can be formed from materials that resist fire and/or abrasion as well. Covering 60 can also be formed from stretchable and/or shape conforming material and secure the padding materials in place by envelope, gusseted or zipper style construction. Although certain preferred embodiments of the present invention have been described above in detail, that is only by way of illustration and example. Those of ordinary skill in the art will now appreciate that modifications and adaptations of this invention can be made to many environments of use and that the examples given are frames of reference only and not application specific requirements. Accordingly, the spirit and scope of the present invention are to be limited only by the terms of the claims below.

A bedding arrangement is provided having a compressible foam mattress pad and compressible foam pillow pad integrated as a single bedding unit within a fluid resistant or impermeable cover whose seams are heat sealed together. Air ventilation through the cover and about the interior foam is permitted by a vent that restricts insect, article and fluid passage through the vent. By using foam of different densities and/or composition, optimum performance characteristics in terms of comfort and support can be obtained separately for the mattress portion and the pillow portion. By mounting two pillow pads within the cover, the bedding arrangement can be made reversible.

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of Korean Application No. 97-11297, filed Mar. 28, 1997, and is a continuation of U.S. patent application Ser. No. 09/419,792 filed in the U.S. Patent and Trademark Office on Oct. 18, 1999 and which issued as U.S. Pat. No. 6,304,540 which is a continuation of U.S. patent application Ser. No. 09/049,988 filed Mar. 30, 1998, which issued as U.S. Pat. No. 6,043,912, the disclosures of which are incorporated herein by reference. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup apparatus compatible with a digital video disk (DVD) and a recordable compact disk (CD-R), and more particularly, to an optical pickup apparatus which can compatibly record information on and read information from a digital video disk (DVD) and a recordable compact disk (CD-R), respectively, using a holographic lens. 2. Description of the Related Art An optical pickup apparatus records and reads the information such as video, audio or data at a high density, and various types of recording media are a disk, a card and a tape. Among them, the disk type is primarily used. Recently, in the field of the optical disk apparatus, a laser disk (LD), a compact disk (CD) and a digital video disk (DVD) have been developed. Such an optical disk includes a plastic or glass medium having a certain thickness along an axial direction to which light is incident, and a signal recording surface on which information is recorded and located on the plastic or glass medium. So far, a high-density optical disk system enlarges a numerical aperture of an objective lens to increase a recording density, and uses a short wavelength light source of 635 nm or 650 nm, Accordingly, the high-density optical disk system can record or read signals on or from a digital video disk, and can also read signals from a CD. However, to be compatible with a recent type of a CD, that is, a recordable CD (CD-R), light having a wavelength of 780 nm should be used, due to the recording characteristic of the CD-R recording medium. As a result, using the light beam wavelengths of 780 nm and 635 (or 650) nm in a single optical pickup becomes very important for compatibility of the DVD and the CD-R. A conventional optical pickup which is compatible with the DVD and the CD-R will be described below with reference to FIG. 1 . FIG. 1 shows an optical pickup using two laser light diodes as light sources for a DVD and a CD-R and a single objective lens. The FIG. 1 optical pickup uses laser light having a wavelength of 635 nm when reproducing a DVD, and uses laser light having a wavelength of 780 nm when recording and reproducing a CD-R. Light having the 635 nm wavelength emitted from a first laser light source 11 is incident to a first collimating lens 12 , in which the light is shown in a solid line. The first collimating lens 12 collimates the incident light beam to be in a parallel light beam. The light beam passing through the first collimating lens 12 is reflected by a beam splitter 13 and then goes to an interference filter prism 14 . Light having the 780 nm wavelength emitted from a second laser light source 21 passes through a second collimating lens 22 , a beam splitter 23 and a converging lens 24 , and then goes to the interference filter prism 14 , in which the light is shown in a dotted line. Here, the light beam of the 780 nm wavelength is converged by the interference filter prism 14 . An optical system having such a structure is called a “finite optical system.” The interference filter prism 14 totally transmits the light beam of the 635 nm wavelength reflected from the beam splitter 13 , and totally reflects the light beam of the 780 nm wavelength converged by the converging lens 24 . As a result, the light beam outgoing from the first laser light source 11 is incident to a quarter-wave plate 15 in the form of a parallel beam by the collimating lens 12 , while the light beam from the second laser light source 21 is incident to the quarter-wave plate 15 in the form of a divergent beam by the converging lens 24 and the interference filter prism 14 . The light transmitted through the quarter-wave plate 15 passes through a variable aperture 16 having a thin film structure and then is incident to an objective lens 17 . The light beam of the 635 nm wavelength emitted from the first laser light source 11 is focused by the objective lens 17 on an information recording surface in the DVD 18 having a thickness of 0.6 mm. Therefore, the light reflected from the information recording surface of the DVD 18 contains information recorded on the information recording surface. The reflected light is transmitted by the beam splitter 13 , and is then incident to a photodetector for detecting optical information. If the finite optical system described above is not used, when the light beam of the 780 nm wavelength emitted from the second laser light source 21 is focused on an information recording surface in the CD-R 25 having a thickness of 1.2 mm using the above described objective lens 17 , spherical aberration is generated due to a difference in thickness between the DVD 18 and the CD-R 25 . The spherical aberration is due to the fact that the distance between the information recording surface of the CD-R 25 and the objective lens 17 is farther than that between the information recording surface of the DVD 18 and the objective lens 17 , along an optical axis. To reduce such a spherical aberration, a construction of a finite optical system including the converging lens 24 is required. By using the variable aperture 16 to be described later with reference to FIG. 2 , the light beam of the 780 nm wavelength forms an optimized beam spot on the information recording surface of the CD-R 25 . The light beam of the 780 nm wavelength reflected from the CD-R 25 is reflected by the beam splitter 23 , and then detected in a photodetector 26 . The thin-film type variable aperture 16 of FIG. 1 , as shown in FIG. 2 , has a structure which can selectively transmit the light beams incident to the regions whose numerical aperture (NA) is less than or equal to 0.6, which coincides with the diameter of the objective lens 17 . That is, the variable aperture 16 is partitioned into two regions based on the numerical aperture (NA) of 0.45 with respect to an optical axis. Among the two regions, a first region 1 transmits both light beams of 635 nm wavelength and 780 nm wavelength. A second region 2 totally transmits the light beam of the 635 nm wavelength and totally reflects the light beam of the 780 nm wavelength. The region 1 is a region having a numerical aperture less than or equal to 0.45, and the region 2 is an outer region relative to the region 1 in which a dielectric thin film is coated. The region 1 is comprised of a quartz ( 5102 ) thin film to remove any optical aberration generated by the dielectric thin film coated region 2 . By using the variable aperture 16 , the 780 nm wavelength light transmitted through the region 1 having the 0.45 NA or below forms a beam spot appropriate to the CD-R 25 on the information recording surface thereof. Thus, the FIG. 1 optical pickup uses an optimum beam spot when a disk mode is changed from the DVD 18 to the CD-R 25 . Accordingly, the FIG. 1 optical pickup is compatible for use with the CD-R. However, the optical pickup shown in FIG. 1 and as described above should form a “finite optical system” with respect to the 780 nm wavelength light in order to remove any spherical aberration generated when changing a DVD compatibly with a CD-R. Also, due to the optical thin film, that is, the dielectric thin film, which is formed in the region 2 of the variable aperture 16 having the NA of 0.45 or above, an optical path difference between the light transmitted through the region 1 having the NA of 0.45 or below and that transmitted through the region 2 having the NA of 0.45 or above, is generated. To eradicate this difference, it is necessary to form an optical thin film in the region 1 . Due to this reason, a quartz coating (SiO 2 ) is formed in the region 1 and a multi-layer thin film is formed in the region 2 . However, such a fabricating process does not only become complicated but also adjustment of the thickness of the thin film should be performed precisely in units of “μm”. Thus, it has been difficult to mass-produce the optical pickup. SUMMARY OF THE INVENTION An object of the present invention is to provide an optical pickup apparatus which is compatible with a digital video disk (DVD) and a recordable compact disk (CD-R), by adopting an infinite optical system and using a holographic lens to remove a spherical aberration generated due to a difference in thickness between optical disks. Additional objects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention. To accomplish the above and other objects of the present invention, there is provided an optical pickup apparatus compatible with at least two types of optical recording media, using light beams having respective different wavelengths for recording and reading information, the optical pickup apparatus including two laser light sources to emit light beams having different wavelengths, respectively, a holographic lens, including a holographic ring, for transmitting both of the light beams emitted from the two laser light sources in an inner region of the holographic ring, and diffracting a specific light beam among the light beams emitted from the laser light sources in an outer region of the holographic ring, an objective lens to focus the light beams passed through the holographic ring lens on the respective information recording surfaces of the two types of the optical recording media, optical elements to alter optical paths of the light beams reflected from the information recording surfaces of the optical recording media, and two photodetectors to individually detect optical information from the light beams incident from the optical elements. BRIEF DESCRIPTION OF THE DRAWINGS These and other objects and advantages of the invention will become apparent and more readily appreciated from the following description of the preferred embodiments, taken in conjunction with the accompanying drawings of which: FIG. 1 is a view showing the construction of a conventional optical pickup; FIG. 2 is a view for explaining the structure of a conventional variable aperture shown in FIG. 1 FIG. 3 is a view showing an optical system of an optical pickup according to an embodiment of the present invention; FIG. 4A is a view showing a positional relationship between a holographic ring lens and an objective lens according to the embodiment of the present invention, and FIG. 4B is a view showing the plane surface of the holographic ring lens; FIG. 5A is a view showing the plane surface of the holographic ring lens, and FIG. 5B is a graphical view showing that part of the FIG. 5A region which is enlarged; FIG. 6 is a graphical view showing transmissive efficiency according to the groove depth of the holographic ring lens with regard to two wavelengths; and FIG. 7 is a view showing that the holographic ring lens and the objective lens are integrally incorporated. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the present preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below in order to explain the present invention by referring to the figures. FIG. 3 shows an optical system of an optical pickup according to an embodiment of the present invention. Referring to FIG. 3 , the optical pickup apparatus includes two laser light sources 31 and 39 for emitting light beams having different wavelengths, respectively, two holographic beam splitters 32 and 40 for altering optical paths of the light beams reflected from information recording surfaces of first and second types of optical disks, a beam splitter 33 for totally transmitting or reflecting the incident light beam according to the light wavelength, a collimating lens 34 for collimating the incident light beam to be in a parallel form, a holographic ring lens 35 for diffracting the incident light beam according to its wavelength, and an objective lens 36 for focusing the light beams on the respective information recording surfaces of optical disks 37 and 41 . Two photodetectors 38 and 42 which detect the light beams reflected from the respective information recording surfaces of the optical disks 37 and 41 and the laser light sources 31 and 39 are integrally incorporated into single modules to form units 30 and 43 , respectively. The operation of the optical pickup constructed above will be described below, in which a DVD and a CD-R are described as optical recording media. First, when recording and/or reading information on a DVD, a light beam having the 650 nm (or 635 nm) wavelength is emitted from the first laser light source 31 and is incident to the holographic beam splitter 32 , in which the light is shown as a solid line. The incident light beam passes through the holographic beam splitter 32 and proceeds to the beam splitter 33 . When recording and/or reading information about a CD-R, a light beam having the 780 nm wavelength is emitted from the second laser light source 39 and is incident to the holographic beam splitter 40 , in which the light is shown as a dotted line. The incident light beam passes through the holographic beam splitter 40 and proceeds to the beam splitter 33 . The beam splitter 33 totally transmits the incident light beam of the 650 nm wavelength and totally reflects the incident light beam of the 780 nm wavelength. The totally transmitted or reflected light beam goes to the holographic ring lens 35 in the form of a parallel beam after passing through the collimating lens 34 . The holographic ring lens 35 selectively diffracts the incident light beam according to the wavelength thereof, to prevent the generation of spherical aberration with regard to the light beams focused on the information recording surfaces of the optical disks 37 and 41 . FIG. 4A is a view showing a positional relationship between the holographic ring lens 35 and an optical surface of the holographic ring lens 35 . As shown in FIG. 4A , the objective lens 36 is partitioned into regions A and B. The region A, being closer to an optical axis of the objective lens 36 , has little effect on a spherical aberration and the region B, being farther from the optical axis, has a large effect on the spherical aberration. Also, the objective lens 36 is most appropriate for a disk having a thin thickness such as a DVD. Thus, when a DVD is exchanged with a thick disk such as a CD-R to operate the optical pickup, the holographic ring lens 35 is required. If the holographic ring lens 35 is not used when recording and/or reading information on the CD-R, the spherical aberration in the beam spot formed on the information recording surface of the disk becomes large, in which the size is more than 1.7 μm. Generally, the size of the beam spot formed on the information recording surface of the CD-R is 1.41 μm. The holographic ring tens 35 diffracts the 780 nm wavelength light beam passed through the region F of the holographic ring lens 35 so as to prevent the generation of spherical aberration, for which a hologram depicted with dots in FIG. 4B is disposed on the region F of the holographic ring lens 35 . Accordingly, the light beam which is incident to the region A of the holographic ring lens 35 , passes through the objective lens 36 without any diffraction by the holographic ring lens 35 , and then is directly focused on the disk. The region F of the light beam which is incident to the holographic ring lens 35 , is wavelength-selectively diffracted by the holographic ring lens 35 and then proceeds to the objective lens 36 . The diffracted light beam of 780 nm wavelength passing through the objective lens 36 makes the size of the beam spot focused on the disk smaller, and no spherical aberration is generated. A focal plane on which the diffracted 780 nm wavelength light beam passing through the region F is focused should coincide with an optimized surface of the disk on which the 780 nm wavelength light beam passing through the region A is focused. By using the holographic ring lens 35 , a working distance from the surface of the objective lens 36 to the information recording surfaces of the disks becomes shorter in the CD-R 41 rather than in the DVD 37 . FIG. 5A is a view showing the structure of the holographic ring lens 35 . The holographic ring lens 35 has an inner region 351 including an optical center of the holographic ring lens 35 , a holographic ring 353 centering at the optical center of the holographic ring lens 35 and surrounding the inner region 351 , and an outer region 355 surrounding the holographic ring 353 . In connection with FIG. 4A , the Inner region 351 coincides with the region A, the holographic ring 353 coincides with the region F, and the outer region 355 coincides with the region B except the region F. A region D shown in FIG. 5B below where the hologram in the holographic ring lens 35 shown in FIG. 5A is provided on the holographic ring 353 , corresponds to the numerical aperture of 0.3-0.5 which is intended to be appropriate to the CD-R. In FIG. 5A , a symbol E indicates the diameter of the objective lens for a DVD whose numerical aperture (NA) is 0.6. Also, the holographic ring lens 35 used in the present invention can selectively adjust the numerical aperture (NA) of the objective lens according to the wavelengths of the light beam, and requires no separate variable aperture. The holographic ring lens 35 has the same function as a general spherical lens which transmits a light beam in the convergent or divergent form. Further, the holographic ring lens 35 has a positive optical power and uses a phase shift hologram as a hologram formed in the holographic ring 353 . An optimized depth of the grooves the hologram should be determined so that the holographic ring 353 selectively diffracts the incident light beam according to the wavelength thereof. The holographic ring lens 35 is constructed so that the light beam of the 650 nm wavelength has transmissive efficiency close to 100% and the light beam of the 780 nm wavelength has a zero-order transmissive efficiency 0% with respect to non-diffracted light beam. For that, in case that the holographic ring 52 has grooves of a constant depth the phase variation by the groove depth of the holographic ring should be about 360° with respect to the 650 nm wavelength light. Since the phase variation is generated by 360°, the holographic ring lens 35 transmits most of the 650 nm wavelength light. The phase variation by the holographic ring 353 should be optimized with respect to the 780 nm wavelength light, by which the 780 nm wavelength light is all diffracted as first-order light. As a result, the holographic ring 353 is designed to hardly diffract the 650 wavelength light, but to diffract the 780 nm wavelength light as a first-order diffracted light. An optimized surface groove depth d of the holographic ring 353 for selectively diffracting 650 nm and 780 nm wavelength light beams is determined by the following equations (1) and (2). 2 ⁢ π ⁢   ⁢ d λ ⁢ ( n - 1 ) = 2 ⁢ m ⁢   ⁢ π ( 1 ) 2 ⁢ π ⁢   ⁢ d λ ′ ⁢ ( n ′ - 1 ) = ( 2 ⁢ m ′ + 1 ) ⁢ λ ( 2 ) Here, λ is the 650 nm wavelength, λ′ is the 780 nm wavelength, and n and n′ denote a reflective index (1.514520) in the 650 nm wavelength and a reflective index (1.511183) in the 780 nm wavelength, respectively. In the above equations (1) and (2), if m=3 and m′=2, the depth d becomes about 3.8 μm. FIG. 5B is a graphical view showing an enlarged view of the hologram region D shown in FIG. 5 A. The hologram which is formed in the holographic ring 353 has grooves of a constant depth by etching or can be manufactured by molding. Further, grooves of the hologram can be formed stepwisely, together with a ring pattern. The grooves of the hologram can also be formed in a blazed type so as to maximize the diffraction efficiency on a non-zeroth order diffracted light. FIG. 6 is a graphical view showing zero-order transmissive efficiency of the holographic ring according to the wavelengths of incident lights. When the surface groove depth d is 3.8 μm, the 650 nm wavelength light is transmitted via the holographic ring 353 by 100% as shown in a solid line overlapped with the symbol “++”, and the 780 nm wavelength light is transmitted via the holographic ring 353 by 0% as shown by a solid line overlapped with a circle. At this time, the holographic ring 353 diffracts the 780 nm wavelength light as the first-order light, in which diffraction efficiency thereof is 40%. All of the 650 nm wavelength light incident to the holographic ring lens 35 having the above characteristics is transmitted and then proceeds to the objective lens 36 . The incident light beam passes through the objective lens 36 and forms a beam spot on the information recording surface of the DVD 37 . The light beam reflected from the information recording surface of the DVD 37 is incident to the holographic ring lens 35 . After passing through the holographic ring lens 35 , the reflected light beam is incident to the collimating lens 34 , the beam splitter 33 and then to the holographic beam splitter 32 , wherein the holographic beam splitter 32 directs the reflected light beam to the photodetector 38 . The 780 nm wavelength light incident to the holographic ring lens 35 is transmitted in the holographic lens 353 and then proceeds to the objective lens 36 as shown in FIG. 4A , but is diffracted in the region A and then proceeds to the objective lens 36 . Therefore, the light beam passing through the objective lens 36 forms an optimized beam spot on the information recording surface of the CD-R 41 . The light beam reflected from the information recording surface of the CD-R 41 is incident to the beam splitter 33 and then reflected. The reflected light proceeds to the holographic beam splitter 40 and then is incident to the photodetector 42 by altering the optical path. The holographic ring lens 35 having the above functions may be manufactured integrally with an objective lens by being etched or molded to a constant depth inwards from one optical surface of the objective lens. The integrally incorporated holographic ring lens has the same function as the holographic ring lens 35 . FIG. 7 is a view showing that the holographic ring lens and the objective lens are integrally incorporated. As described above, the optical pickup apparatus according to the present invention is used compatibly with a DVD and a CD-R, by using a holographic ring lens to eliminate a spherical aberration generated in response to a disk being changed to another disk having a different thickness, in which a working distance is shorter in the case of the CD-R than the DVD. Also, the optical pickup apparatus provides advantages which include ease in construction of a holographic ring lens and good mass-production capabilities. While only certain embodiments of the invention have been specifically described herein, it will be apparent that numerous modifications may be made thereto without departing from the spirit and scope of the invention.

An optical pickup apparatus compatible with at least two types of optical recording media, using light beams having respective different wavelengths for recording and reading information, the optical pickup apparatus including two laser light sources to emit light beams having the different wavelengths, a holographic lens including a holographic ring to transmit the light beams incident in an inner region of the holographic ring, and to diffract a specific light beam among the light beams emitted from the laser light sources incident in an outer region relative to the inner region, an objective lens to focus the light beams passed through the holographic ring lens on the respective information recording surfaces of the two types of the optical recording media, optical elements to alter optical paths of the light beams reflected from the information recording surfaces of the optical recording media to corresponding photodetectors.

RELATED APPLICATIONS The present invention was first described in a notarized Official Record of Invention on Jul. 31, 2009, that is on file at the offices of Montgomery Patent and Design, LLC, the entire disclosures of which are incorporated herein by reference. FIELD OF THE INVENTION The present invention relates generally to knife-style gate valves, and in particular, to a knife-style gate valve including an elastomeric liner construction particularly suited for use on wet scrubbers to control liquid slurry flow. BACKGROUND OF THE INVENTION Gate valves, also known as knife valves or slide valves, are a common item in industrial plants around the world. They are used in pipelines to control the flow of material through them. Their design ensures that pressure drops across an open valve are kept to a minimum. They are particularly useful when used with slurries or high viscosity liquids such as heavy oils, grease, or thick food products. However, their design also causes accelerated corrosion and erosion of seat and wedge surfaces due to their exposure. Over time, this erosion and corrosion will lead to failure of the valve requiring replacement which is not only costly from a time and labor standpoint, but from lost production from the associated industrial process as well. One (1) approach has been to attempt to construct gate valves with liners to combat these disadvantages. Various attempts have been made to provide gate valves with liners for industrial use. Examples of these attempts can be seen by reference to several U.S. patents including U.S. Pat. No. 2,893,684; U.S. Pat. No. 3,993,092; U.S. Pat. No. 4,009,727; U.S. Pat. No. 4,201,365; U.S. Pat. No. 7,100,893; and U.S. Pat. No. 7,350,766. While these apparatuses fulfill their respective, particular objectives, each of these references suffer from one (1) or more disadvantages including an undesirably substantial number of mechanical connections and specialized tools or machinery required during manufacture, installation, operation, and repair; limitations in molding, manufacture, and assembly of various components, particularly liner constructions such as found in U.S. Pat. No. 3,993,092 and U.S. Pat. No. 7,100,893; and eventual leakage and failure due to fatigue on gate or liner portions of the apparatus. Accordingly, there exists a need for a knife-style gate valve and liner without the disadvantages as described above. The development of the present invention substantially departs from the conventional solutions and in doing so fulfills this need. SUMMARY OF THE INVENTION In view of the foregoing references, the inventor recognized the aforementioned inherent problems. Thus, the object of the present invention is to solve the aforementioned disadvantages and provide for this need. To achieve the above objectives, it is an object of the present apparatus to comprise many of the same components as found in common gate valve manufacturing including a near body assembly and a distal body assembly providing a characteristic assembly that can be used in normal piping systems being connected in a conventional manner via four (4) system connection apertures to flanged portions of the piping system, formation from a standard material such as carbon steel or stainless steel, a yoke providing containment and control of various components, and a bonnet for mounting a hand wheel and a stem which enable actuation of the apparatus. The near and distal body assemblies comprise a plurality of viewing holes providing a means to identify an open or closed state of the gate. Another object of the present invention is to form the gate, a wetted component of the apparatus, of a high quality stainless steel and to include a liner for which the particular material construction would vary based upon the specific application. It is envisioned that primary applications of the apparatus would be in application such as Flue Gas Desulfurization (FGD) and more specifically on use on wet scrubbers to control the flow of abrasive slurries. Yet still another object of the present invention is to provide a design which can be widely applied to many industry fields, such as chemical plants, power plants, pulp and paper mills, and wastewater treatment plants, mining fields, sugar mills and food-processing facilities. In addition, the design of this knife gate valve can reduce the use of non-renewable natural resources, such as Hastelloy, and avoid the environmental pollution by heavy metals. Yet still another object of the present invention is to mount the gate within a wiper which operates at a close tolerance. The wiper is formed from a high quality elastomeric urethane liner and allows the gate to operate in between a near body liner and distal body liner also formed from a high quality elastomeric urethane liner. In this manner the wiper, the near body liner, and the distal body liner are the only components of the apparatus that are wetted, or actually touch the liquid or liquid slurry that is controlled by the valve. Yet still another object of the present invention is to provide enhanced corrosion resistance, reduced wear, longer life, and reduced leakage as compared to common gate valves due to the elastomeric nature of the aforementioned components and the gate. This construction is further envisioned to provide superior waterproofing and corrosion resistance. Yet still another object of the present invention is to locate the gate inside of the wiper in a location where the gate can interrupt a flow of liquids or liquid slurry through the near body liner and distal body liner. Yet still another object of the present invention is to hold the elastomeric components of the apparatus in place with a friction fit inside of the near body assembly and the distal body assembly with a plurality of connection bolts in lieu of mechanical fastening. The assembly process enables simple manual assembly of the apparatus without the need for complicated tooling such as presses, coatings or other aids. This assembly can also be reversed to aid in repair and replacement of the wetted components under field conditions, allowing for a fast return to service and reduced down time requiring only common hand tools. Yet still another object of the present invention is to provide a method of utilizing the device including assembling a majority of the components used in the knife-style gate valve with elastomeric liner such as the near body assembly, the distal body assembly, the yoke, the bonnet, the hand wheel, the stem, and the connection bolts using conventional materials and following conventional manufacturing techniques; manufacturing the specialized components of the wiper, the near body liner and the distal body liner using elastomeric materials; assembling the aforementioned components in a manner that allows for fast manufacturing as well as fast repair using normal procedures; installing the valve within a piping system in a similar manner to a common gate valve; and using the valve to control abrasive fluids as previously described until replacement or repair is required. Further objects and advantages of the present invention will become apparent from a consideration of the drawings and ensuing description. BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present disclosure will become better understood with reference to the following more detailed description and claims taken in conjunction with the accompanying drawings, in which like elements are identified with like symbols, and in which: FIG. 1 is a front view of the knife-style gate valve with elastomeric liner 10 according to the preferred embodiment of the present invention; FIG. 2 is a sectional view of the knife-style gate valve with elastomeric liner 10 as seen along a line I-I, as shown in FIG. 1 , according to the preferred embodiment of the present invention; FIG. 3 a is a partially exploded view of the knife-style gate valve with elastomeric liner 10 according to the preferred embodiment of the present invention; FIG. 3 b is another partially exploded view of the knife-style gate valve with elastomeric liner 10 according to the preferred embodiment of the present invention; FIG. 3 c is still another partially exploded view of the knife-style gate valve with elastomeric liner 10 according to the preferred embodiment of the present invention; and, FIG. 3 d is yet another partially exploded view of the knife-style gate valve with elastomeric liner 10 according to the preferred embodiment of the present invention. DESCRIPTIVE KEY 10 knife-style gate valve with elastomeric liner 15 gate valve assembly 20 near body assembly 25 distal body assembly 60 gate 30 first connection bolt 35 yoke 40 bonnet 45 hand wheel 50 stem 55 second connection bolts 57 viewing hole 58 system connection apertures 65 wiper 70 link pin 75 near body liner 80 distal body liner DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The best mode for carrying out the disclosure is presented in terms of a preferred embodiment, herein depicted within FIGS. 1 through 3 d . However, the disclosure is not limited to a single described embodiment and a person skilled in the art will appreciate that many other embodiments are possible without deviating from the basic concept of the disclosure and that any such work around will also fall under its scope. It is envisioned that other styles and configurations can be easily incorporated into the teachings of the present disclosure, and only one particular configuration may be shown and described for purposes of clarity and disclosure and not by way of limitation of scope. The terms “a” and “an” herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced items. Referring now to FIG. 1 , a front view of the knife-style gate valve with elastomeric liner 10 , according to the preferred embodiment of the present invention, is disclosed. This figure demonstrates a gate valve assembly 15 comprised of many of the same components as found in the conventional teachings of gate valve manufacturing. A near body assembly 20 and a distal body assembly 25 (not visible in this figure) produce a characteristic assembly that can be used in normal piping systems being connected in a conventional manner via four (4) system connection apertures 58 to flanged portions of said piping system. The material of construction of the near body assembly 20 and distal body assembly 25 (not visible in this figure) is of standard material such as carbon steel, stainless steel, or the like. A yoke 35 is located above the gate valve assembly 15 and provides containment and control for remaining components of the knife-style gate valve with elastomeric liner 10 . It should be noted that the near body assembly 20 and the distal body assembly 25 are incorporated with the yoke 35 on each respective side. Differentiation is made as the purpose of each respective assembly and not to said construction. A bonnet 40 is provided atop the yoke 35 and provides a mounting surface for a hand wheel 45 and a stem 50 . When rotary motion is applied to the hand wheel 45 and subsequently transferred to the stem 50 , the knife-style gate valve with elastomeric liner 10 is actuated. The direction of the rotary motion determines whether the knife style gate valve with elastomeric liner 10 is opening or closing as would normally be expected. Additionally, the near body assembly 20 and the distal body assembly 25 comprise a plurality of viewing holes 57 providing a means to identify an open or closed state of the gate 60 . Viewing through an upper pair of viewing holes 57 in said body assemblies 20 , 25 provides visibility of an upper edge of said gate 60 when in the open or raised state. In like manner, a lower pair of viewing holes 57 in each body assembly 20 , 25 provides viewing of said upper edge of the gate 60 when said gate is in a closed or lowered state. Components are attached to the bonnet 40 and held captive by a set of four (4) second connection bolts 55 (only two (2) of which are visible in this orientation). Specialized components of the knife style gate valve with elastomeric liner 10 are primarily located inside of the near body assembly 20 and distal body assembly 25 (not visible in this figure) and will be described in greater detail herein below. Referring next to FIG. 2 , a sectional view of the knife-style gate valve with elastomeric liner 10 , as seen along a line I-I, as shown in FIG. 1 , according to the preferred embodiment of the present invention is depicted. The near body assembly 20 and the distal body assembly 25 are held captive by four (4) first 30 connection bolts. The near body assembly 20 and the distal body assembly 25 would be made of conventional material such as cast iron. The hand wheel 45 and the stem 50 are likewise connected to the bonnet 40 by the second connection bolts 55 as aforementioned described. The stem 50 is connected to a gate 60 via a link pin 70 . The gate 60 , a wetted component of the knife-style gate valve with elastomeric liner 10 is made of a high quality stainless steel. The exact makeup of the liner would vary from application to application and would depend upon the specific application. It is envisioned that primary applications of the knife-style gate valve with elastomeric liner 10 would be in application such as Flue Gas Desulfurization (FGD) applications and more specifically on use on wet scrubbers to control the flow of abrasive slurries. It can also be widely applied to many industry fields, such as chemical plants, power plants, pulp and paper mills, and wastewater treatment plants, mining fields, sugar mills and food-processing facilities. In addition, the design of this knife gate valve can reduce the use of non-renewable natural resources, such as Hastelloy, and avoid the environmental pollution by heavy metals. The gate 60 is mounted within a wiper 65 which operates at a close tolerance. The wiper 65 is of a high quality elastomeric urethane liner. The wiper 65 allows the gate 60 to operate in between a near body liner 75 and a distal body liner 80 . Both the near body liner 75 and the distal body liner 80 are manufactured of high quality elastomeric urethane liner. It should be noted that the wiper 65 , the near body liner 75 , and the distal body liner 80 are the only components of the knife-style gate valve with elastomeric liner 10 that are wetted, or actually touch the liquid and/or liquid slurry that is controlled by the knife-style gate valve with elastomeric liner 10 . Similarly, the wiper 65 , the near body liner 75 , and the distal body liner 80 are the only components of the knife-style gate valve with elastomeric liner 10 that are made with the high quality elastomeric liner while the gate 60 is made of stainless steel. Such material may be solid in nature, or may surround a core made of more rigid material such as metal. The elastomeric nature of said components provides for enhanced corrosion resistance, reduced wear, longer life, and reduced leakage when compared to conventional valves. It will also provide better waterproof and corrosion resistant performance as well. Referring now to FIG. 3 a , a partially exploded view of the knife style gate valve with elastomeric liner 10 according to the preferred embodiment of the present invention is shown. This figure clearly shows the components of the knife style gate valve with elastomeric liner 10 that are made of elastomeric materials, namely the gate 60 , the wiper 65 , the near body liner 75 and the distal body liner 80 shown in a general position and relationship to one another. Note that the wiper 65 is separate from the gate 60 , but is simply shown together for the purposes of illustration. The gate 60 is inserted inside of the wiper 65 , and in a location where the gate 60 may interrupt flow of liquids and/or liquid slurry through the near body liner 75 and distal body liner 80 . It should be noted that these elastomeric components are not held in place via any direct mechanical or adhesive means attached to them directly. In lieu of such mechanical fastening, the gate 60 , the wiper 65 , and the near body liner 75 are held via a friction fit inside of the near body assembly 20 and the distal body assembly 25 via the first connection bolts 30 (as shown in FIG. 1 and FIG. 2 ). Additional descriptions herein below will further describe the assembly process. Said assembly process provides for easy hand assembly with the need for complicated tooling such as presses, coatings or other aids. Said assembly can also be reversed to aid in repair and replacement of the wetted components under field conditions allowing for a fast return to service and reduced down time using only common hand tools. Referring next to FIG. 3 b , another partially exploded view of the knife-style gate valve with elastomeric liner 10 according to the preferred embodiment of the present invention is disclosed. This figure shows the distal body liner 80 installed inside of the distal body assembly 25 and held in place via a friction fit. Likewise the near body liner 75 (not visible in this configuration) is placed within the near body assembly 20 . The gate 60 and wiper 65 remain as depicted in FIG. 3 a awaiting installation. Referring now to FIG. 3 c , still another partially exploded view of the knife-style gate valve with elastomeric liner 10 according to the preferred embodiment of the present invention is depicted. This figure shows the gate 60 and wiper 65 in place against the distal body assembly 25 and distal body liner 80 awaiting additional construction. As aforementioned described the near body liner 75 (not visible in this configuration) remains placed within the near body assembly 20 awaiting additional manufacturing steps. Referring finally to FIG. 3 d , yet another partially exploded view of the knife-style gate valve with elastomeric liner 10 according to the preferred embodiment of the present invention is shown. This figure shows all materials made of elastomeric materials, namely the gate 60 , the wiper 65 , the near body liner 75 and the distal body liner 80 , placed within the confines of the near body assembly 20 and the distal body assembly 25 . Such components are held in place and are secured via the first connection bolts 30 and the second connection bolts 55 as shown in FIG. 1 and FIG. 2 . Said construction is not unlike that afforded by conventional gate valves. The time interval between the construction steps depicted in FIG. 3 a and FIG. 3 d is envisioned to be only minutes. Similar but reverse construction techniques would be followed for repair and/or rebuilding activities. In a non-limiting exemplary embodiment of the present invention 10 , the gate valve assembly 15 may be intercalated between the distal and near body assemblies 25 , 20 . The hand wheel 45 preferably actuates the gate valve assembly 15 between the distal and near body assemblies 25 , 20 respectively, and subjacent to the stem 50 . Advantageously, rotation of the hand wheel 45 causes the gate 60 to linearly reciprocate through the wiper 65 . In this manner, the stem 50 preferably rotates in sync with the hand wheel 45 . It is envisioned that other styles and configurations of the present invention can be easily incorporated into the teachings of the present invention, and only one particular configuration shall be shown and described for purposes of clarity and disclosure and not by way of limitation of scope. The preferred embodiment of the present invention can be utilized by the common user in a simple and effortless manner with little or no training. It is envisioned that the knife-style gate valve with elastomeric liner 10 would be constructed in general accordance with FIG. 1 through FIG. 3 d. The majority of the components used in the knife-style gate valve with elastomeric liner 10 such as the near body assembly 20 , the distal body assembly 25 , the first connection bolts 30 , the yoke 35 , the bonnet 40 , the hand wheel 45 , the stem 50 , and the second connection bolts 55 would be made using conventional materials and follow conventional manufacturing techniques. The specialized components of the wiper 65 , the near body liner 75 and the distal body liner 80 , would be made using elastomeric materials. Said components would be the only components of the knife-style gate valve with elastomeric liner 10 that would come in contact with controlled or transferred material, hence the name “wetted”. Said assembly of the gate 60 , the wiper 65 , the near body liner 75 and the distal body liner 80 , within the near body assembly 20 and distal body assembly 25 would follow the specific steps outlined within FIGS. 3 a - 3 d . This procedure would allow for fast manufacture as well as fast repair using normal procedures. At this point in time, the knife-style gate valve with elastomeric liner 10 is ready for specific application as a gate valve. The knife-style gate valve with elastomeric liner 10 would be installed within a piping system using the system connection apertures 58 in the same manner as any other gate valve. The overall dimensions of the knife-style gate valve with elastomeric liner 10 would closely follow those of conventional gate valves allowing for retrofit applications. The knife-style gate valve with elastomeric liner 10 would be held in place via the first connection bolts 30 as would be normally expected. At this point in time the knife-style gate valve with elastomeric liner 10 would be placed in service controlling abrasive fluids as aforementioned described until replacement or repair would be required. The foregoing descriptions of specific embodiments have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit to the precise forms disclosed and many modifications and variations are possible in light of the above teachings. The embodiments were chosen and described in order to best explain principles and practical application to enable others skilled in the art to best utilize the various embodiments with various modifications as are suited to the particular use contemplated.

A knife gate valve for specific environments comprises a knife valve with a body, a hand wheel, a yoke sleeve, a gland packing, a gland bushing, a stem, a wedge gate, seating surfaces and the like. All internal components of the device are provided with a high quality elastomeric liner. This surface is present on wetted surfaces such as body, seat and wedge surfaces exposed to the controlled material. This feature provides corrosion resistance, long life, and reduces leakage when compared to conventional valves. Its new style of internal design provides waterproof resistance for virtually types of industrial applications.

CROSS REFERENCE TO RELATED APPLICATION [0001] This application is a divisional of U.S. patent application Ser. No. 12/106,562, filed Apr. 21, 2008, now U.S. Pat. No. 8,114,300. TECHNICAL FIELD [0002] Embodiments of the invention relate to methods of fabricating thin films of self-assembling block copolymers, and devices resulting from those methods. BACKGROUND OF THE INVENTION [0003] As the development of nanoscale mechanical, electrical, chemical and biological devices and systems increases, new processes and materials are needed to fabricate nanoscale devices and components. Making electrical contacts to conductive lines has become a significant challenge as the dimensions of semiconductor features shrink to sizes that are not easily accessible by conventional lithography. Optical lithographic processing methods have difficulty fabricating structures and features at the sub-30 nanometer level. The use of self assembling diblock copolymers presents another route to patterning at nanoscale dimensions. Diblock copolymer films spontaneously assemble into periodic structures by microphase separation of the constituent polymer blocks after annealing, for example by thermal annealing above the glass transition temperature of the polymer or by solvent annealing, forming ordered domains at nanometer-scale dimensions. [0004] The film morphology, including the size and shape of the microphase-separated domains, can be controlled by the molecular weight and volume fraction of the AB blocks of a diblock copolymer to produce lamellar, cylindrical, or spherical morphologies, among others. For example, for volume fractions at ratios greater than about 80:20 of the two blocks (AB) of a diblock polymer, a block copolymer film will microphase separate and self-assemble into a periodic spherical domains with spheres of polymer B surrounded by a matrix of polymer A. For ratios of the two blocks between about 60:40 and 80:20, the diblock copolymer assembles into a periodic hexagonal close-packed or honeycomb array of cylinders of polymer B within a matrix of polymer A. For ratios between about 50:50 and 60:40, lamellar domains or alternating stripes of the blocks are formed. Domain size typically ranges from 5-50 nm. [0005] In some applications, the self-assembled films are further processed to selectively remove one of the blocks, leaving the other polymer block as an etch mask on the substrate. However, in some applications, the polymer block that is removed does not extend completely through the film and requires an additional etch of material to expose the underlying substrate, resulting in a reduction in the aspect ratio of the mask openings and the subsequently etched line or other opening in the substrate. [0006] It would be useful to provide methods of fabricating films of ordered nanostructures that can be readily used to in semiconductor manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS [0007] Embodiments of the invention are described below with reference to the following accompanying drawings, which are for illustrative purposes only. Throughout the following views, the reference numerals will be used in the drawings, and the same reference numerals will be used throughout the several views and in the description to indicate same or like parts. [0008] FIG. 1 illustrates an elevational, cross-sectional view of the substrate showing a block copolymer material within trenches in a substrate. [0009] FIG. 2 illustrates a cross-sectional view of the substrate of FIG. 1 at a subsequent stage showing a self-assembled block copolymer film composed of parallel cylinders within the trenches. FIG. 2A is a top plan view of a portion of the substrate of FIG. 2 taken along lines 2 A- 2 A. [0010] FIG. 3 illustrates a diagrammatic top plan view of a portion of a substrate at a preliminary processing stage according to an embodiment of the present disclosure. FIGS. 3A-3B are elevational, cross-sectional views of the substrate depicted in FIG. 3 taken along lines 3 A- 3 A and 3 B- 3 B, respectively. [0011] FIG. 4 illustrates a top plan view of the substrate of FIG. 3 at a subsequent stage showing the formation of trenches in a material layer formed on a substrate. FIGS. 4A-4B illustrate elevational, cross-sectional views of a portion of the substrate depicted in FIG. 4 taken, respectively, along lines 4 A- 4 A and 4 B- 4 B. [0012] FIGS. 5-8 are top plan views of the substrate of FIG. 4 at subsequent stages in the fabrication of a self-assembled block copolymer film according to an embodiment of the disclosure. FIGS. 5A-8A illustrate elevational, cross-sectional views of a portion of the substrate depicted in FIGS. 5-8 taken along lines 5 A- 5 A to 8 A- 8 A, respectively. FIGS. 5B-8B are cross-sectional views of the substrate depicted in FIGS. 5-8 taken along lines 5 B- 5 B to 8 B- 8 B, respectively. FIG. 8C is a top plan view of the substrate depicted in FIG. 8A taken along lines 8 C- 8 C. [0013] FIGS. 9-10 are top plan views of the substrate of FIG. 8 at subsequent stages, illustrating an embodiment of the removal of one of the polymer blocks to form a mask to etch the substrate. FIGS. 9A-10A illustrate elevational, cross-sectional views of a portion of the substrate depicted in FIGS. 9-10 taken along lines 9 A- 9 A and 10 A- 10 A, respectively. FIGS. 9B-10B are cross-sectional views of the substrate depicted in FIGS. 9-10 taken along lines 9 B- 9 B to 10 B- 10 B, respectively. [0014] FIG. 11 is a top plan view of the substrate of FIG. 10 at a subsequent stage, illustrating filling of the etched openings in the substrate. FIGS. 11A-11B illustrate elevational, cross-sectional views of a portion of the substrate depicted in FIG. 11 taken along lines 11 A- 11 A and 11 B- 11 B, respectively. DETAILED DESCRIPTION OF THE INVENTION [0015] The following description with reference to the drawings provides illustrative examples of devices and methods according to embodiments of the invention. Such description is for illustrative purposes only and not for purposes of limiting the same. [0016] In the context of the current application, the term “semiconductor substrate” or “semiconductive substrate” or “semiconductive wafer fragment” or “wafer fragment” or “wafer” will be understood to mean any construction comprising semiconductor material, including but not limited to bulk semiconductive materials such as a semiconductor wafer (either alone or in assemblies comprising other materials thereon), and semiconductive material layers (either alone or in assemblies comprising other materials). The term “substrate” refers to any supporting structure including, but not limited to, the semiconductive substrates, wafer fragments or wafers described above. [0017] “L o ” as used herein is the inherent periodicity or pitch value (bulk period or repeat unit) of structures that self assemble upon annealing from a self-assembling (SA) block copolymer. “L B ” as used herein is the periodicity or pitch value of a blend of a block copolymer with one or more of its constituent homopolymers. “L” is used herein to indicate the center-to-center cylinder pitch or spacing of cylinders of the block copolymer or blend, and is equivalent to “L o ” for a pure block copolymer and “L B ” for a copolymer blend. [0018] FIGS. 1-2 illustrate the fabrication of a self-assembled film from a cylindrical-phase block copolymer (e.g., PS-b-P2VP) to form cylinders that are oriented parallel to the substrate surface. As shown in FIG. 1 , a substrate 10 (with active areas 12 ) is provided with an overlying material layer 14 that has been etched to form trenches 16 separated by spacers 18 . The trenches include sidewalls 20 , ends 22 and a floor 24 that are preferential wetting to the minority block of the block copolymer material, e.g., oxide, etc. The width (w t ) of the trenches 16 is about 1.5*L and the depth (D t ) is about L. The thickness (t) of the block copolymer material 26 is about 1.5*L. [0019] As depicted in FIGS. 2-2A , annealing produces a self-assembled film 28 composed of parallel cylinders 30 (diameter (d)˜0.5*L) of the minority block (e.g., P2VP) embedded within (or surrounded by) a matrix 32 of the majority block (e.g., PS) of the block copolymer material. A brush layer 30 a (thickness 0.5*L) forms on the preferential wetting surfaces (e.g., oxide, etc.) of the trenches and over the surface of the material layer 14 as a bilayer composed of the minority block wetting the trench surfaces. For example, a layer of P2VP domains will wet oxide interfaces, with attached PS domains directed away from the oxide material. [0020] The resulting film 28 with parallel cylinders 30 can be used, for example, for patterning lines, but is not useful for fabricating an etch mask for patterning vias. In addition, a thickness of the block copolymer material 26 at about 1.5*L is required at the time of annealing to produce the parallel cylinders as continuous lines. [0021] In embodiments of the invention, a polymer material (e.g., film, layer) is prepared by guided self-assembly of block copolymers, with both polymer domains at the air interface. Block copolymer materials spontaneously assemble into periodic structures by microphase separation of the constituent polymer blocks after annealing, forming ordered domains at nanometer-scale dimensions. In embodiments of the invention, a cylindrical-phase block copolymer layer with ordered structures is formed as a base layer or film within a trench and used as a template to induce ordering of a subsequently deposited cylindrical-phase block copolymer resulting in a stacked double- or multi-layer structure having perpendicular-oriented cylinders in a polymer matrix. Following self assembly, the pattern of perpendicular-oriented cylinders that is formed can then be used, for example, as an etch mask for patterning nanosized features (e.g., vias) into the underlying substrate through selective removal of one block of the self-assembled block copolymer. [0022] A method for fabricating a self-assembled block copolymer material that defines an array of nanometer-scale, perpendicular-oriented cylinders according to an embodiment of the invention is illustrated in FIGS. 3-8 . [0023] The described embodiment involves a thermal anneal of a cylindrical-phase block copolymer in combination with a graphoepitaxy technique that utilizes a lithographically defined trench as a guide with a floor, sidewalls and ends that are preferential wetting to one polymer block and function as constraints to induce self-assembly of the block copolymer of the base layer into an ordered one-dimensional (1-D) array of perpendicular-oriented cylindrical domains (“perpendicular cylinders”) within a polymer matrix, and the cylindrical-phase block copolymer of the overlying layer into cylinders in a polymer matrix oriented perpendicular and registered to the underlying perpendicular cylinders. In some embodiments, multiple lines of the underlying perpendicular cylinders can be formed in each trench with the overlying perpendicular-oriented cylinders. [0024] The term “perpendicular cylinders” used herein is understood to refer to the structure of the minority block of the base layer within the trenches, which shape can range from a half-sphere to an elongated cylinder with a rounded end, and is embedded within (surrounded by) a matrix of the majority block with a face wetting the air interface. The conditions provided in embodiments of the invention induce an orientational transition relative to the trench floor/substrate from parallel-oriented cylinders (“surface-parallel” cylinders) to perpendicular-oriented cylinders (“surface-normal” cylinders). [0025] As depicted in FIGS. 3-3B , a substrate 10 ′ is provided. As further illustrated, conductive lines 12 ′ (or other active area, e.g., semiconducting regions) are situated within the substrate 10 ′. [0026] A material layer 14 ′ (or one or more material layers) is formed over the substrate 10 ′ and etched to form trenches 16 ′ that are oriented perpendicular to an array of conductive lines 12 ′, as shown in FIGS. 4-4B . Portions of the material layer 14 ′ form a spacer 18 ′ outside and between the trenches. The trenches 16 ′ are structured with opposing sidewalls 20 ′, opposing ends 22 ′, a floor 24 ′, a width (w t ), a length (l t ) and a depth (D t ). [0027] In any of the described embodiments, a single trench or multiple trenches can be formed in the material layer 14 ′, and can span the entire width of an array of lines (or other active area). In embodiments of the invention, the substrate 10 ′ is provided with an array of conductive lines 12 ′ (or other active areas) at a pitch of L. The trench or trenches are formed over the active areas 12 ′ (e.g., lines) such that when the block copolymer material is annealed, each cylinder will be situated above a single active area 12 ′ (e.g., conductive line). In some embodiments, multiple trenches are formed with the ends 22 ′ of each adjacent trench 16 ′ aligned or slightly offset from each other at less than 5% of L such that cylinders in adjacent trenches are aligned and situated above the same line 12 ′. [0028] Single or multiple trenches 16 ′ (as shown) can be formed using a lithographic tool having an exposure system capable of patterning at the scale of L (10-100 nm). Such exposure systems include, for example, extreme ultraviolet (EUV) lithography, proximity X-rays and electron beam (e-beam) lithography, as known and used in the art. Conventional photolithography can attain (at smallest) about 58 nm features. [0029] A method called “pitch doubling” or “pitch multiplication” can also be used for extending the capabilities of photolithographic techniques beyond their minimum pitch, as described, for example, in U.S. Pat. No. 5,328,810 (Lowrey et al.), U.S. Pat. No. 7,115,525 (Abatchev, et al.), US 2006/0281266 (Wells) and US 2007/0023805 (Wells). Briefly, a pattern of lines is photolithographically foamed in a photoresist material overlying a layer of an expendable material, which in turn overlies a substrate, the expendable material layer is etched to form placeholders or mandrels, the photoresist is stripped, spacers are formed on the sides of the mandrels, and the mandrels are then removed leaving behind the spacers as a mask for patterning the substrate. Thus, where the initial photolithography formed a pattern defining one feature and one space, the same width now defines two features and two spaces, with the spaces defined by the spacers. As a result, the smallest feature size possible with a photolithographic technique is effectively decreased down to about 30 nm or less. [0030] Factors in forming a 1-D array of perpendicular cylinders within the trenches include the width (w t ) of the trench, the formulation of the block copolymer or blend to achieve the desired pitch (L), and the total volume or thickness (t 2 ) of the block copolymer material within the trench at the end of the anneal at less than 2*L. [0031] The width (w t ) of the trench can be varied according to the desired number of rows and pattern of perpendicular cylinders. In the illustrated embodiment, the trenches 16 ′ are constructed with a width (w t ) of about 1.5*L (or 1.5× the pitch value) of the block copolymer to form a single row of perpendicular cylinders. A cast block copolymer material (or blend) of about L and having a total thickness of less than 2*L at the end of anneal will self assemble within the trenches 16 ′ into perpendicular cylinders in a single row or line that is aligned with the sidewalls down the center of each trench 16 ′ with a center-to-center pitch distance (p) between adjacent perpendicular cylinders at or about the pitch distance or L value of the block copolymer material. For example, in using a cylindrical-phase block copolymer with an about 35 nm pitch value or L, the width (w t ) of the trenches 16 ′ can be about 1.5*35 nm or about 55 nm to form a single row of perpendicular cylinders (each at about 20 nm diameter). [0032] There is a shift from two rows to one row of the perpendicular cylinders as the width (w t ) of the trench is decreased and/or the periodicity (L value) of the block copolymer is increased, for example, by forming a ternary blend by the addition of both constituent homopolymers. The boundary conditions of the trench sidewalls 20 ′ in both the x- and y-axis impose a structure wherein each trench contains “n” number of features (e.g., n lines of perpendicular cylinders). [0033] For example, in embodiments of the invention in which a trench has a width greater than 1.5*L, for example, a width of about 2*L to about 2.5*L, a cylindrical-phase block copolymer with a pitch of L and having a total thickness of less than 2*L at the end of anneal will self-assemble to form perpendicular cylinders in a hexagonal array or a zigzag pattern with adjacent cylinders offset by about 0.5*L for the length (b) of the trench, rather than a single line row of perpendicular cylinders each separated by about L (center-to-center distance) and aligned with the sidewalls down the center of the trench. For example, a cylindrical-phase block copolymer material having a L value of about 35 nm within a trench having a width of about 2-2.5*L or about 70-87.5 nm will self assemble to form a hexagonal array of perpendicular cylinders (about 20 nm diameter) with a center-to-center pitch distance between adjacent cylinders of about 0.5*L value. [0034] The depth (D t ) of the trenches 16 ′ is effective to direct lateral ordering of the block copolymer material during the anneal. In embodiments of the invention, the depth (D t ) of the trenches 16 ′ is at or less than the final thickness (t 2 ) of the block copolymer material (D t ≦t 2 ), which minimizes the formation of a meniscus and variability in the thickness of the block copolymer material across the trench width. In some embodiments, the trench depth is about 50-90% less, or about one-half to about two-thirds (about ½-⅔, or about 50%-67%) less than the final thickness (t 2 ) of the block copolymer material within the trench. [0035] The length (l t ) of the trenches 16 ′ is according to the desired number of perpendicular cylinders in a row, and is generally at or about n*L or an integer multiple of L, and typically within a range of about n*10 to about n*100 nm (with n being the number of features or structures, e.g., perpendicular cylinders). [0036] The width of the mesas or spacers 18 ′ between adjacent trenches can vary and is generally about L to about n*L. In some embodiments, the trench dimension is about 20-100 nm wide (w t ) and about 100-25,000 μm in length (l t ) with a depth (D t ) of about 10-100 nm. [0037] The trench sidewalls 20 ′, ends 22 ′ and floor 24 ′ are preferential wetting by a minority block of the block copolymer to induce registration of cylinders (of the minority block) in a perpendicular orientation to the trench floor as the polymer blocks self-assemble to form the base layer 28 ′. The substrate 10 ′ and material layer 14 ′ can be formed from the same or a highly similar material that is inherently preferential wetting to the minority (preferred) polymer block (e.g., PMMA of a PS-b-PMMA material) or, in other embodiments, a preferential wetting material can be applied onto the surfaces of the trenches 16 ′. [0038] To provide preferential wetting surfaces, for example, in the use of a PS-b-PMMA or PS-b-PVP block copolymer, the substrate 10 ′ and the material layer 14 ′ can be composed of an inherently preferential wetting material such as a clean silicon surface (with native oxide), oxide (e.g., silicon oxide, SiO x ), silicon nitride, silicon oxycarbide, indium tin oxide (ITO), silicon oxynitride, and resist materials such as methacrylate-based resists and polydimethyl glutarimide resists, among other materials, which exhibit preferential wetting toward the preferred block (e.g., the minority block) (e.g., PMMA, PVP, etc.). Upon annealing and self assembly of the block copolymer material, the preferred (minority) block (e.g., the PMMA block, PVP block, etc.) will form a thin interface layer along the preferential wetting surfaces 20 ′, 22 ′, 24 ′ of the trenches. [0039] In other embodiments utilizing PS-b-PMMA, a preferential wetting material such as a polymethylmethacrylate (PMMA) polymer modified with an —OH containing moiety (e.g., hydroxyethyl methacrylate) can be applied onto the surfaces of the trenches. An OH-modified PMMA can be applied, for example, by spin coating and then heating (e.g., to about 170° C.) to allow the terminal —OH groups to end-graft to oxide surfaces (e.g., sidewalls 20 ′, ends 22 ′, floor 24 ′). Non-grafted material can be removed by rinsing with an appropriate solvent (e.g., toluene). See, for example, Mansky et al., Science, 1997, 275, 1458-1460, and In et al., Langmuir, 2006, 22, 7855-7860. [0040] Referring now to FIGS. 5-5B , a self-assembling, cylindrical-phase block copolymer material 26 ′ having an inherent pitch at or about L o (or a ternary blend of block copolymer and homopolymers blended to have a pitch at or about L B ) is deposited into the trenches 16 ′ to form a base layer 28 ′. [0041] Nonlimiting examples of diblock copolymers include, for example, poly(styrene)-b-poly(methylmethacrylate) (PS-b-PMMA) or other PS-b-poly(acrylate) or PS-b-poly(methacrylate), poly(styrene)-b-poly(vinylpyridine) (PS-b-PVP), poly(styrene)-b-poly(lactide) (PS-b-PLA), and poly(styrene)-b-poly(tert-butyl acrylate) (PS-b-PtBA), poly(styrene)-b-poly(ethylene-co-butylene (PS-b-(PS-co-PB)), poly(styrene)-b-poly(ethylene oxide) (PS-b-PEO), polybutadiene-b-poly(vinylpyridine) (PB-b-PVP), poly(ethylene-alt-propylene)-b-poly(vinylpyridine) (PEP-b-PVP), and poly(styrene)-b-poly(dimethylsiloxane) (PS-b-PDMS), among others, with PS-b-PMMA used in the illustrated embodiment. Other types of block copolymers (i.e., triblock or multiblock copolymers) can be used. Examples of triblock copolymers include ABC copolymers such as poly(styrene-b-methyl methacrylate-b-ethylene oxide) (PS-b-PMMA-b-PEO), and ABA copolymers such as PS-PMMA-PS, PMMA-PS-PMMA, and PS-b-PI-b-PS, among others. [0042] In some embodiments of the invention, the block copolymer or blend is constructed such that the minor domain can be selectively removed. [0043] The L value of the block copolymer can be modified, for example, by adjusting the molecular weight of the block copolymer. The block copolymer material can also be formulated as a binary or ternary blend comprising a block copolymer and one or more homopolymers (HPs) of the same type of polymers as the polymer blocks in the block copolymer, to produce a blend that will swell the size of the polymer domains and increase the L value. The concentration of homopolymers in a blend can range from 0 to about 60 wt-%. Generally, when added to a polymer material, both homopolymers are added to the blend in about the same ratio or amount. An example of a ternary diblock copolymer/homopolymer blend is a PS-b-PVP/PS/PVP blend, for example, 60 wt-% of 32.5 K/12 K PS-b-PVP, 20 wt-% of 10K PS, and 20 wt-% of 10K PVP. Another example of a ternary diblock copolymer/homopolymer blend is a PS-b-PMMA/PS/PMMA blend, for example, 60 wt-% of 46K/21K PS-b-PMMA, 20 wt-% of 20K polystyrene and 20 wt-% of 20K poly(methyl methacrylate). Yet another example is a blend of 60:20:20 (wt-%) of PS-b-PEO/PS/PEO, or a blend of about 85-90 wt-% PS-b-PEO and up to 10-15 wt-% PEO homopolymer. [0044] The film morphology, including the domain sizes and periods (L) of the microphase-separated domains, can be controlled by chain length of a block copolymer (molecular weight, MW) and volume fraction of the AB blocks of a diblock copolymer to produce cylindrical morphologies (among others). For example, in embodiments of the invention, for volume fractions at ratios of the two blocks generally between about 60:40 and 80:20, the diblock copolymer will microphase separate and self-assemble into periodic perpendicular cylinder domains of polymer B within a matrix of polymer A. An example of a cylinder-forming PS-b-PVP copolymer material (L o ˜28 nm) to form about 14 nm diameter perpendicular cylinder PVP domains in a matrix of PS is composed of about 70 wt-% PS and 30 wt-% PVP with a total molecular weight (M n ) of 44.5 kg/mol. An example of a cylinder-forming PS-b-PMMA copolymer material (L o =35 nm) to form about 20 nm diameter perpendicular cylinder PMMA domains in a matrix of PS is composed of about 70 wt-% PS and 30 wt-% PMMA with a total molecular weight (M n ) of 67 kg/mol. As another example, a PS-b-PLA copolymer material (L=49 nm) can be composed of about 71 wt-% PS and 29 wt-% PLA with a total molecular weight (M n ) of about 60.5 kg/mol to form about 27 nm diameter perpendicular cylinder PLA domains in a matrix of PS. [0045] The block copolymer material can be deposited by spin casting (spin-coating) from a dilute solution (e.g., about 0.25-2 wt % solution) of the block copolymer in an organic solvent such as dichloroethane (CH 2 Cl 2 ) or toluene, for example. Capillary forces pull excess block copolymer material 26 ′ (e.g., greater than a monolayer) into the trenches 16 ′. As shown in FIG. 5A , a thin layer or film 26 a ′ of the block copolymer material can be deposited onto the material layer 14 ′ outside the trenches, e.g., on the mesas/spacers 18 ′. Upon annealing, the thin film 26 a ′ (in excess of a monolayer) will flow off the mesas/spacers 18 ′ into the trenches leaving a structureless brush layer on the material layer 14 ′ from a top-down perspective. [0046] Referring now to FIGS. 6-6B , the block copolymer material 26 ′ is then annealed to form the self-assembled base layer 28 ′. [0047] Upon annealing, the cylindrical-phase block copolymer material (e.g., PS-b-PMMA) will self-assemble in response to the constraints provided by the width (w t ) of the trench 16 ′ and the character of the cylindrical-phase block copolymer composition 26 ′ (e.g., PS-b-PMMA having an inherent pitch at or about L) combined with trench surfaces 20 ′, 22 ′, 24 ′ that are preferential wetting by the minority or preferred block of the block copolymer (e.g., the PMMA block), and a total thickness (t 2 ) of the BCP material 26 ′ within the trench of less than 2*L at the end of anneal. Enthalpic forces drive the wetting of a preferential-wetting surface by the preferred block (e.g., the minority block). In some embodiments in which the width (w) of the trench is greater than 1.5*L, an ordered hexagonal array of perpendicular cylinders can be formed in each trench. [0048] The resulting base layer 28 ′ is composed of a monolayer of perpendicular cylinder domains 34 ′ of the preferred (minority) block (e.g., PMMA) within a matrix 36 ′ of the majority polymer block (e.g., PS) oriented perpendicular to the trench floor 24 ′ and registered and aligned parallel to the trench sidewalls 20 ′ in a row down the middle of each trench for the length of the trench and spaced apart at a center-to-center pitch distance of about L. The face 38 ′ of the perpendicular cylinders wets the air interface (surface exposed) and the opposing ends 40 ′ are embedded in (surrounded by) the polymer matrix 36 ′. The diameter (d) of the perpendicular cylinders 34 ′ will generally be about one-half of the center-to-center distance (pitch distance, p) between the perpendicular cylinders. Upon annealing, a layer of the minority (preferred) block segregates to and wets the sidewalls 20 ′, ends 22 ′ and floor 24 ′ of the trenches to form a thin brush wetting layer 34 a ′ with a thickness of generally about 0.5*L. The brush layer 34 a ′ is a bilayer of the minority block domains (e.g., PMMA) wetting trench (e.g., oxide) interfaces with attached majority block domains (e.g., PS) directed away from the trench surfaces and in contact with the majority block domains (e.g., PS) of the matrix 36 ′ at the surface of the perpendicular cylinder domains 34 ′. [0049] The resulting morphology of the annealed polymer material base layer 28 ′, i.e., the perpendicular orientation of the perpendicular cylinders 34 ′, can be examined, for example, using atomic force microscopy (AFM), transmission electron microscopy (TEM), scanning electron microscopy (SEM). [0050] In some embodiments, the self-assembled base layer 28 ′ is defined by an array of perpendicular cylinders 34 ′ in a polymer matrix 36 ′ and a brush layer 34 a ′ (at about 0.5*L thick), each cylinder 34 ′ having a rounded end 40 ′ and a diameter at or about 0.5*L, with the number (n) of perpendicular cylinders in the row according to the length of the trench, and the center-to-center distance (pitch distance, p) between perpendicular cylinders at or about L. [0051] The block copolymer material 26 ′ is cast into the trenches 16 ′ to an initial thickness (t 1 ) such that upon completion of inflow of polymer material off the mesas/spacers 18 ′ into the trenches and at the end of the anneal, the total volume or thickness (t 2 ) of the block copolymer material 26 ′ will induce and result in the formation of perpendicular cylinders 34 ′ in the trench. [0052] In embodiments of the invention, the block copolymer material 26 ′ within the trenches at the end of the anneal has an insufficient volume of polymer material to fully form surface parallel cylinders ( 30 ) that would typically result under the same or similar conditions (e.g., of trench width (w t ), trench depth (D t ), block copolymer material at about L, preferentially wetting trench surfaces). The total volume or thickness (t 2 ) of the block copolymer (BCP) material 26 ′ after the anneal is effective to induce a transition from a surface parallel to a surface normal (or perpendicular) orientation of cylindrical domains relative to the trench floor/substrate surface. The thickness of the block copolymer material 26 ′ can be measured, for example, by ellipsometry techniques. [0053] For example, to form the surface parallel cylinder morphology 30 as illustrated in FIGS. 1-2 , in the application of a block copolymer (such as PS-b-P2VP) in which the minority block (e.g., P2VP) is strongly preferentially wetting to the trench surfaces (e.g., oxide) and the majority block is preferential wetting to the air interface (e.g., PS, which has a lower surface tension, preferentially wets a clean dry air atmosphere), a typical thickness (t) of the block copolymer material 26 at the end of the anneal to form a monolayer of parallel cylinders (and a brush layer 30 a ) is t=b+L (where b is the thickness of the brush layer 30 a at about 0.5*L), or t=0.5*L+L=1.5*L. [0054] According to embodiments of the invention, the thickness (t 2 ) of a block copolymer material 26 ′ such as PS-b-P2VP at the end of the anneal should be sufficiently less than the thickness t=b+L (e.g., t<1.5*L) to result in a switch in the orientation of the cylinders from surface parallel ( FIG. 2 , cylinders 30 ) to perpendicular (or surface normal) ( FIG. 6A , cylinders 34 ′) while retaining the brush layer 34 a ′ in contact with the trench surfaces 20 ′, 22 ′, 24 ′. In addition, the face 38 ′ of the perpendicular cylinders 34 ′ wets the air interface and the opposing ends 40 ′ are rounded. In some embodiments, the total volume or thickness (t 2 ) of a PS-b-P2VP block copolymer material 26 ′ (or similar polymer material) after inflow from the mesas/spacers 18 ′ and at the end of anneal is about 5-30% less (or about 10-20% less) than the 1.5*L value of the block copolymer material, or t 2 ˜70-95%*(1.5*L). For example, for a PS-b-P2VP block copolymer material where L=35 nm, the PS-b-P2VP block copolymer material 26 ′ can be cast into the trenches 16 ′ and the polymer material 26 a ′ caused to flow into the trenches wherein the total volume or thickness (t 2 ) of the block copolymer material 26 ′ at the end of anneal is [(about 0.70 to about 0.95)*(1.5*35 nm)], or about 36.75-49.9 nm thick. [0055] In embodiments utilizing a block copolymer (such as PS-b-PMMA) in which the minority block (e.g., PMMA) is preferentially wetting to trench surfaces (e.g., oxide) and both the minority block and the majority block (e.g., PS) wet the air interface equally well, the typical thickness (t 2 ) of the block copolymer material 26 to form a monolayer of parallel cylinders (over a brush layer 30 a ) ( FIGS. 1-2 ) is generally t 2 ˜L. According to embodiments of the invention, a film 26 ′ of a block copolymer material such as PS-b-PMMA within the trenches 16 ′ at the end of anneal should be at less than the L value or t 2 <L to result in a reorientation of the cylinders from parallel to perpendicular with a brush layer 34 a ′ in contact with the trench surfaces 20 ′, 22 ′, 24 ′. In this application, the cylinders 34 ′ have a shorter length and appear as half-spheres due to the rounded ends 40 ′. In some embodiments, the total volume or thickness (t 2 ) of a PS-b-PMMA block copolymer material 26 ′ (or similar material) after inflow from the mesas/spacers 18 ′ and at the end of anneal is about 5-30% less (or about 10-20% less) than the L value of the block copolymer material, or t 2 ˜70-95%*(1*L). For example, for a PS-b-PMMA block copolymer material where L=35 nm, the PS-b-PMMA block copolymer material 26 ′ can be cast into the trenches 16 ′ and the polymer material 26 a ′ caused to flow into the trenches wherein the total volume or thickness (t 2 ) of the block copolymer material 26 ′ after the anneal is [(about 0.70 to about 0.95)*(35 nm)], or about 24.5-33.25 nm thick, resulting in surface normal (perpendicular) cylinders 34 ′ within the trenches. [0056] In embodiments utilizing a block copolymer material (such as PS-b-PDMS) in which the minority block (e.g., PDMS) preferentially wets both the trench surfaces and air interface, the typical thickness (t 2 ) of the block copolymer material 26 to form a monolayer of parallel cylinders (over a brush layer 30 a ) ( FIGS. 1-2 ) is generally t 2 =2*L. According to embodiments of the invention, a film 26 ′ of a block copolymer material such as PS-b-PDMS within trenches 16 ′ at the end of anneal should have a thickness (t 2 ) of less than about 2*L (or at t 2 <2*L) to result in a reorientation to perpendicular cylinders 34 ′ ( FIG. 6A ) in which the cylinders are perpendicular to the trench floor 24 ′ with rounded ends 40 ′. In some embodiments, the total volume or thickness (t 2 ) of PS-b-PDMS block copolymer material 26 ′ (or similar material) after anneal is about 5-30% less (or about 10-20% less) than 2*L value of the block copolymer material, or t 2 ˜70-95%*(2*L). For example, for a PS-b-PDMS block copolymer material where L=35 nm, the PS-b-PDMS block copolymer material 26 ′ can be cast into the trenches 16 ′ and the polymer material 26 a ′ caused to flow into the trenches wherein the total volume or thickness (t 2 ) of the block copolymer material 26 ′ after the anneal is [(about 0.70 to about 0.95)*(2*35 nm)], or about 49-66.5 nm thick. [0057] The polymer material 26 ′ can be annealed to form the polymer base layer 28 ′, for example, by thermal annealing to above the glass transition temperature of the component blocks of the copolymer material to cause the polymer blocks to separate and self assemble in response to the preferential wetting of the trench surfaces 20 ′, 22 ′, 24 ′. For example, a PS-b-PMMA copolymer film can be annealed at a temperature of about 150-275° C. in a vacuum oven for about 1-24 hours to achieve the self-assembled morphology. [0058] The block copolymer material 26 ′ can be globally heated or, in other embodiments, a zone or localized thermal anneal can be applied to portions or sections of the block copolymer material 26 ′. For example, the substrate can be moved across a temperature gradient 42 ′ ( FIG. 6A ), for example, a hot-to-cold temperature gradient, positioned above (as shown) or underneath the substrate (or the thermal source can be moved relative to the substrate, e.g., arrow→) such that the block copolymer material self-assembles upon cooling after passing through the heat source. Only those portions of the block copolymer material that are heated above the glass transition temperature of the component polymer blocks will self-assemble, and areas of the material that were not sufficiently heated remain disordered and unassembled. “Pulling” the heated zone across the substrate can result in faster processing and better ordered structures relative to a global thermal anneal. [0059] After the block copolymer material is annealed and ordered, the base layer (film) 28 ′ can then be treated to crosslink one of the polymer domains to fix and enhance the strength of the polymer domain, for example, the polymer matrix 36 ′ (e.g., the PS segments to make the PS matrix insoluble). The polymer block can be structured to inherently crosslink (e.g., upon UV exposure) or formulated to contain a crosslinking agent. [0060] Generally, the block copolymer material 26 a ′ outside the trenches will not be thick enough to result in self-assembly. Optionally, the unstructured thin film 26 a ′ of the block copolymer material outside the trenches (e.g., on mesas/spacers 18 ′) can be removed, as illustrated in FIGS. 6A-6B , for example, by an etch technique or a planarization process. For example, the trench regions can be selectively exposed through a reticle (not shown) to crosslink only the annealed and self-assembled polymer material 28 ′ within the trenches 16 ′, and a wash can then be applied with an appropriate solvent (e.g., toluene) to remove the non-crosslinked portions of the block copolymer material 26 a ′ (e.g., on the spacers 18 ′), leaving the registered self-assembled base layer 28 ′ within the trench and exposing the surface ( 18 ′) of the material layer 14 ′ above/outside the trenches. In another embodiment, the polymer material 26 ′ can be crosslinked globally, a photoresist material can be applied to pattern and expose the areas of the polymer material 26 a ′ outside the trench regions, and the exposed portions of the polymer material 26 a ′ can be removed, for example by an oxygen (O 2 ) plasma treatment. [0061] The annealed and self-assembled base film 28 ′ is then used as a template for inducing the ordering of an overlying cylindrical-phase block copolymer material such that the cylindrical domains of the annealed second film will orient perpendicular and registered to the underlying pattern of perpendicular cylinders in the base film. [0062] As depicted in FIGS. 7-7B , a cylindrical-phase block copolymer (BCP) material 44 ′ having an inherent pitch at or about the L value of the block copolymer material 26 ′ of the base layer 28 ′ (or a ternary blend of block copolymer and homopolymers blended to have a pitch at or about the L value) is deposited (e.g., by spin casting) onto the annealed (and crosslinked) base layer 28 ′ within the trenches 16 ′. The block copolymer material 44 ′ can be deposited to a thickness (t 3 ) at or about its L value. The minority domain of the BCP material 44 ′ is either identical to or preferentially wets the perpendicular cylinder (minority) domains 34 ′ of the underlying base layer 28 ′. [0063] The block copolymer material 44 ′ is then annealed to form a self-assembled material layer 46 ′ over the base layer 28 ′, as depicted in FIGS. 8A-8C . The polymer material 44 ′ can be annealed, for example, by thermal annealing. [0064] During the anneal, the chemical pattern of the perpendicular cylinder (minor) domains 34 ′ of the base layer 28 ′ templates and imposes an induced ordering effect on the self-assembling cylindrical-phase block copolymer material 44 ′ to form a layer 46 ′ of perpendicular-oriented cylinders 48 ′ of the minority (preferred) block (e.g., PMMA) within a polymer matrix 50 ′ of the majority block (e.g., PS), with the cylinders registered to the underlying pattern of perpendicular cylinders 34 ′ of the base layer 28 ′. The diameter of the perpendicular cylinders 48 ′ is at or about 0.5*L. [0065] In addition, parallel cylinders 30 ′ embedded in the matrix 50 a ′ and a brush layer 30 a ′ will form over the preferential wetting material layer 14 ′, as shown in FIGS. 8A-8B . [0066] Intrinsic periods of the two block copolymer materials 26 ′, 44 ′ can be matched, for example, through a ternary blend of either or both of the copolymer materials with one or more homopolymers to adjust the polymer periods (L values). See, for example, R. Ruiz, R. L. Sandstrom and C. T. Black, “Induced Orientational Order in Symmetric Diblock Copolymer Thin-Films,” Advanced Materials, 2007, 19(4), 587-59. In embodiments of the method, the same cylindrical-phase block copolymer material is used for both block copolymer materials 26 ′, 44 ′. [0067] The annealed and self-assembled polymer layer 46 ′ can then be treated to cross-link one of the polymer segments (e.g., the PS matrix 50 ′), as previously described. [0068] After annealing and ordering of the cylindrical-phase BCP material 44 ′ to form polymer material layer 46 ′, one of the block components can be selectively removed to produce a porous film that can be used, for example, as a lithographic template or mask to pattern the underlying substrate 10 ′ in a semiconductor processing to define a regular pattern of nanometer sized openings (i.e., about 10-100 nm). [0069] As illustrated in FIGS. 9-9B , in some embodiments, the cylindrical domains 48 ′ and the underlying perpendicular cylinders 34 ′ of the base layer 28 ′ are selectively removed to form a porous film of regular cylindrical-shaped voids or openings 54 ′ within a polymer matrix 36 ′, 50 ′ that are registered to the trench sidewalls 20 ′. For example, selective removal of PMMA domains 34 ′, 48 ′ from a cross-linked PS matrix 36 ′, 50 ′ can be performed, for example, by application of an oxygen (O 2 ) plasma, or by a chemical dissolution process such as acetic acid sonication by first irradiating the sample (ultraviolet (UV) radiation, 1 J/cm̂2 254 nm light), then ultrasonicating the film in glacial acetic acid, ultrasonicating in deionized water, and rinsing the film in deionized water to remove the degraded PMMA. [0070] As shown, a portion of the PS matrix 36 ′ situated underneath the openings 54 ′ and over the trench floor 24 ′ remains after the removal of the PMMA domains 34 ′, 48 ′. The underlying PS matrix 36 ′ can be removed, for example, by a reactive ion etch (RIE) using an oxygen plasma, for example, to expose the underlying substrate 10 ′ at the trench floor 24 ′, as illustrated in FIGS. 10-10B . The resulting polymer film 52 ′ is composed of cylindrical openings 54 ′ within the polymer matrix 36 ′, 50 ′ (e.g., of PS). The RIE etch may thin the polymer matrix 50 ′, as shown, although not to a significant extent. [0071] An embodiment of the application of the polymer film 52 ′ is as an etch mask to form openings in the substrate 10 ′. For example, as illustrated in FIGS. 10-10B , the polymer film 52 ′ can then be used as a mask to etch (arrows 1 ) a series of cylindrical openings or contact holes 56 ′ (shown in phantom) to the conductive lines 12 ′ or other active area (e.g., semiconducting region, etc.) in the underlying substrate 10 ′ (or an underlayer), for example, using a selective RIE plasma etch process. [0072] Further processing can then be performed as desired. For example, as depicted in FIGS. 11-11B , the residual polymer material 52 ′ (e.g., 50 ′, 34 a ′, 36 ′) can be removed and the substrate openings 56 ′ can be filled with a material 58 ′ such as a metal or metal alloy such as Cu, Al, W, Si, and Ti 3 N 4 , among others, to form arrays of cylindrical contacts to the conductive lines 12 ′. The cylindrical openings 56 ′ in the substrate can also be filled with a metal-insulator-metal stack to form capacitors with an insulating material such as SiO 2 , Al 2 O 3 , HfO 2 , ZrO 2 , SrTiO 3 , and the like. [0073] Methods of the disclosure provide a means of generating self-assembled diblock copolymer films composed of perpendicular-oriented cylinders in a polymer matrix. The methods provide ordered and registered elements on a nanometer scale that can be prepared more inexpensively than by electron beam lithography, EUV photolithography or conventional photolithography. The feature sizes produced and accessible by this invention cannot be easily prepared by conventional photolithography. Since the domain sizes and periods (L) involved in this method are determined by the chain length of a block copolymer (MW), resolution can exceed other techniques such as conventional photolithography. Processing costs using the technique are significantly less than extreme ultraviolet (EUV) photolithography, which has comparable resolution. The described methods and systems can be readily employed and incorporated into existing semiconductor manufacturing process flows and provide a low cost, high-throughput technique for fabricating small structures. [0074] Embodiments of the invention eliminate the need for preparing trench floors that wet both blocks of a block copolymer to form perpendicular-oriented cylinders from block copolymer materials. While forming a neutral wetting trench floor can be accomplished, for example, by forming a neutral wetting material (e.g., random copolymer material) on the trench floor, it requires either processes that are not conventional to semiconductor manufacturing and/or extra processing steps. The present methods do not require unconventional processes for manufacturing the required structures. [0075] In addition, embodiments of the disclosure providing chemical pattern templating of the upper layer provide fast processing of BCP materials relative to other methods of registering block copolymers such as processes that utilize graphoepitaxy with selective/neutral wetting trench or groove surfaces alone. The present methods provide formation of nanostructures in a manner that is more readily manufacturable. [0076] Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that any arrangement which is calculated to achieve the same purpose may be substituted for the specific embodiments shown. This application is intended to cover any adaptations or variations that operate according to the principles of the invention as described. Therefore, it is intended that this invention be limited only by the claims and the equivalents thereof. The disclosures of patents, references and publications cited in the application are incorporated by reference herein.

Methods for fabricating sublithographic, nanoscale polymeric microstructures utilizing self-assembling block copolymers, and films and devices formed from these methods are provided.

BACKGROUND OF THE PRESENT INVENTION [0001] 1. Field of Invention [0002] The present invention relates to a burner, and more specifically to a centrally fuel rich (CFR) swirl coal combustion burner which can reduce the output of the emissions amount of NOx. [0003] 2. Description of Related Arts [0004] Nitrogen Oxide (NOx) is one of the main contaminants for air pollution. It not only forms the acid rain to damage the ecological environment, but also forms the actinic fog to harm the health of human being. The coal combustion is one of the main sources of the generation of nitrogen oxide compound. At the present, there are two methods to control the formation of NOx. The first method is low NOx combustion technology which can reduce the formation of NOx. The second method is the flue gas denitrification which applies removing reactant of denitrification to the flue gas to remove NOx. China Patent, CN1207511C, publication date of Jun. 22, 2005, entitled “Centrally Fuel Rich (CFR) Swirl Coal Combustion burner”, teaches the control of the formation of NOx, as the first method, to control the formation of NOx. Accordingly, the burner comprises a pulverized separator having a cone shape to collect the pulverized coal at the central portion of a primary air-coal mixture duct, wherein the injection of the pulverized coal is aligned with a center of the central recirculation zone of the burner. Throughout the combustion of the pulverized coal, the concentration of the pulverized coal is increased within the central recirculation zone while the residence time of pulverized coal is prolonged to reduce the formation of NOx. However, there is no conical outlet installed at the outlets of the primary air-coal mixture, inner and outer secondary air ducts, the pulverized coal at the primary air-coal mixture and inner and outer secondary air ducts is parallelly spurted into the furnace so that the central recirculation zone formed by the swirl of the secondary air is relatively small. Thus, the residence time of pulverized coal in the central recirculation is not long enough to inhibit the formation of nitrogen oxide compound at most. Also, without the conical outlet, the air through the primary air-coal mixture and secondary air ducts is mixed immediately into the furnace, so that the ability of NOx reduction is substantially decreased. Therefore, it cannot effectively inhibit the formation of NOx. Furthermore, the major drawbacks of the second method of controlling the nitrogen oxide compound, through the flue gas denitrification by applying removing reactant of denitrification to flue gas to remove nitrogen oxide compound, are high investment cost and operating cost. SUMMARY OF THE PRESENT INVENTION [0005] A main object of the present invention is to provide a low NOx swirl coal combustion burner, which can solve the problem of the conventional CFR swirl coal combustion burner being ineffectively inhibited the formation of fuel-NOx. [0006] Accordingly, in order to accomplish the above objects, the present invention provides a low NOx swirl coal combustion burner comprises a primary air-coal mixture duct, a conical pulverized coal separator, a secondary air wind box, and an inner secondary air vane, wherein the primary air-coal mixture duct is coaxially extended through the secondary air wind box. The pulverized coal separator is supported within the primary air-coal mixture duct, wherein an outlet of the pulverized coal separator, having a smaller diameter, is alignedly pointing towards an outlet of the of primary air-coal mixture duct. Inner and outer tubular sleeves are encirclingly coupled with the primary air-coal mixture duct to form an inner secondary air duct and an outer secondary air duct within the secondary air wind box. The present invention further comprises a primary air-coal mixture conical outlet, an inner secondary air conical outlet, and an outer secondary air conical outlet. The opening of the primary air-coal mixture conical outlet, with a smaller diameter, is coupled with the outlet of the primary air-coal mixture duct. The opening of the inner secondary air conical outlet, with a smaller diameter, is coupled with the outlet of the inner secondary air duct. The opening of the outer secondary air conical outlet, with a smaller diameter, is coupled with the outlet of the outer secondary air duct. [0007] Accordingly, the present invention achieves the following advantages. [0008] The secondary air flow is partitioned into two portions into the furnace through the inner and outer secondary air ducts, wherein the inner and outer secondary air vanes are arranged to regulate the two portions of the secondary air flow in a swirling manner at the inner secondary air duct and the outer secondary air duct respectively. Under the effects of the primary air-coal mixture conical outlet, the inner secondary air conical outlet, and the outer secondary air conical outlet, the flow of air-coal mixture at the primary air-coal mixture duct is mixed with the swirling air flow at the inner and outer secondary air ducts to form a moderate central recirculation zone. In addition, the burner of the present invention does not include any central duct. The primary air-coal mixture duct is located at a center of the burner, wherein the primary air-coal mixture flow is formed in a non-swirling manner that the primary air-coal mixture flow is straight-forwardly passing through the primary air-coal mixture duct. One or more pulverized coal separators are coaxially supported within the primary air-coal mixture duct along the centerline thereof to inject the flow of air-coal mixture at the center of primary air-coal mixture duct into the furnace, so as to increase the amount of the pulverized coal at the central recirculation zone, to enhance the reduction ability of the air-coal mixture at the central recirculation zone, and to prolong the residence time of the air-coal mixture at the center recirculation zone for effectively reducing the formation of NOx. The conical outlets are arranged to delay the mixing time of the primary air-coal mixture and secondary air flows through the primary air-coal mixture and inner and outer secondary air ducts and to further prolong the residence time in the center recirculation zone under the reduction ability so as to effectively reduce the formation of NOx. Accordingly, the secondary air flow is partitioned into two portions for being transversely injected into the furnace. The inner portion of the secondary air flow is used as an igniter for igniting the pulverized coal. The outer portion of the secondary air flow is used as an oxygen suppler for supplying enough oxygen for complete combustion of the pulverized coal, so as to inhibit the formation of NOx. The staged mixing manner of the secondary air flow at the radial direction has an advantage of reducing the emission of NOx. [0009] These and other objectives, features, and advantages of the present invention will become apparent from the following detailed description, the accompanying drawings, and the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS [0010] FIG. 1 is a sectional view of a low NOx swirl coal combustion burner according to a preferred embodiment of the present invention, wherein an outer secondary air vane is omitted. [0011] FIG. 2 is the sectional view of the low NOx swirl coal combustion burner according to the above preferred embodiment of the present invention, illustrating the outer secondary air vane being installed. [0012] FIG. 3 is a sectional view of a curved vane blade of the low NOx swirl coal combustion burner according to the above preferred embodiment of the present invention. [0013] FIG. 4 is a top view of the curved vane blade the low NOx swirl coal combustion burner according to the above preferred embodiment of the present invention. [0014] FIG. 5 is a sectional view of an outer secondary air vane according to the above preferred embodiment of the present invention, illustrating the structural relationship between the outer secondary air vane and the outer secondary air duct. [0015] FIG. 6 is a sectional view of the inner secondary air vane welded on the wall of the primary air-coal mixture duct of the low NOx swirl coal combustion burner according to the above preferred embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT [0016] Referring to FIGS. 1 and 2 of the drawings, a low NOx swirl coal combustion burner according to a preferred embodiment of the present invention is illustrated, wherein the low NOx swirl coal combustion burner comprises a primary air-coal mixture duct 1 , a conical pulverized coal separator 2 , a secondary air wind box 3 , an inner secondary air vane 4 , a primary air-coal mixture conical outlet 11 , an inner secondary air conical outlet 12 , and an outer secondary air conical outlet 13 . [0017] The primary air-coal mixture duct 1 is coaxially extended through the secondary air wind box 3 , wherein the pulverized coal separator 2 is supported within the primary air-coal mixture duct 1 . An outlet of the pulverized coal separator 2 , which is an opening having a smaller diameter, is alignedly pointing towards an outlet of the primary air-coal mixture duct 1 . Inner and outer tubular sleeves 7 , 8 are encirclingly coupled with the primary air-coal mixture duct 1 to form an inner secondary air duct 9 and an outer secondary air duct 10 within the secondary air wind box 3 . The inner secondary air vane 4 is supported within the inner secondary air duct 9 . The opening of the primary air-coal mixture conical outlet 11 , with a smaller diameter, is coupled with the outlet of the primary air-coal mixture duct 1 . The opening of the inner secondary air conical outlet 12 , with a smaller diameter, is coupled with an outlet of the inner secondary air duct 9 . The opening of the outer secondary air conical outlet 13 , with a smaller diameter, is coupled with an outlet of the outer secondary air duct 10 . [0018] As shown in FIGS. 1 and 2 , a set of pulverized coal separators 2 is spacedly supported within primary air-coal mixture duct 1 . In particularly, the pulverized coal separators 2 are coaxially supported within the primary air-coal mixture duct 1 along the centerline K. The diameter of each of the pulverized coal separators 2 is gradually reducing towards the outlet of the primary air-coal mixture duct 1 while the diameters of the pulverized coal separators 2 are sequentially reducing towards the outlet of the primary air-coal mixture duct 1 . Therefore, when the flow of the pulverized coal passes through the pulverized coal separators 2 along the primary air-coal mixture duct 1 , a high-dense pulverized coal region is formed at the central portion of the primary air-coal mixture duct 1 while a less-dense pulverized coal region is formed near the inner wall of the primary air-coal mixture duct. [0019] As shown in FIGS. 1 and 2 , the inner secondary air duct 9 and the outer secondary air duct 10 are coaxially formed with respect to the primary air-coal mixture duct 1 such that the inner secondary air duct 9 , an outer secondary air duct 10 , and the primary air-coal mixture duct 1 share a common axis. Accordingly, the coaxial configuration of the primary air-coal mixture duct 1 , the inner secondary air duct 9 and the outer secondary air duct 10 enhances the circulation of the primary air-coal mixture and secondary air flows passing therethrough. [0020] As shown in FIGS. 1 and 2 , the primary air-coal mixture conical outlet 11 is extended inclinedly at an angle α with respect to the centerline K of the primary air-coal mixture duct 1 . The inner secondary air conical outlet 12 is extended inclinedly at an angle β with respect to the centerline K of the primary air-coal mixture duct 1 . The outer secondary air conical outlet 13 is extended inclinedly at an angle γ with respect to the centerline K of the primary air-coal mixture duct 1 . Accordingly, the angles α, β, γ are the same, wherein each of the angles α, β, γ has a threshold between 15° to 35°. It is worth to mention that if the angles α, β, γ are larger than the threshold, the air divergent angle will be substantially increased to form an open airflow. Therefore, pulverized coal will flow near to the water-cooling wall region so as to cause the deterioration of combustion and the slagging at the water-cooling wall. If the angles α, β, γ are smaller than the threshold, the primary air-coal mixture conical outlet 11 , the inner secondary air conical outlet 12 , and the outer secondary air conical outlet 13 will take no effect as the structure without the conical outlet 11 , the inner secondary air conical outlet 12 , and the outer secondary air conical outlet 13 . In other words, the smaller angles α, β, γ will incapable of forming a moderate central recirculation zone and keeping a stable flame. Therefore, the angles α, β, γ of the conical outlets 11 , 12 , 13 are set within the threshold will have great influence on stabilizing the combustion and forming the moderate central recirculation zone to reduce the emission amount of NOx. [0021] As shown in FIGS. 3 , 4 , and 6 , the inner secondary air vane 4 comprises a set of curved vane blades 6 , wherein each of the curved vane blades 6 has a curved configuration. Accordingly, the curved vane blades 6 are evenly, radially, and outwardly extended from the outer circumferential wall of the primary air-coal mixture duct 1 within the inner secondary air duct 9 . In particularly, the corresponding edge of each of the curved vane blades 6 is securely affixed to the outer circumferential wall of the primary air-coal mixture duct 1 . Accordingly, the structural configuration of the inner secondary air vane 4 has a simple structure and is adapted to distribute uniform air flow. [0022] As shown in FIGS. 1 and 2 , the burner of the present invention further comprises an inner secondary air damper 16 supported at an inlet of the inner secondary air duct 9 , wherein the opening valve of the inner secondary air damper 16 is selectively adjusted to adjustably control the amount of air flow passing through the inner secondary air duct 9 and the outer secondary air duct 10 . Accordingly, the air flow is guided to pass through the inner secondary air duct 9 in a swirling manner while the air flow is guided to straight-forwardly pass through the outer secondary air duct 10 in a non-swirling manner. By selectively regulating the flow ratio of the air flow between the inner secondary air duct 9 and the outer secondary air duct 10 to adjust the swirl intensity of the air flow, the magnitude of the central recirculation zone is adapted to be adjustably controlled. [0023] As shown in FIGS. 1 , 2 , and 5 , the burner of the present invention further comprises an outer secondary air vane 5 supported at an inlet of the outer secondary air duct 10 to regulate the air flow passing through the outer secondary air duct 10 in a swirling manner. Therefore, the air flow is guided to pass through the inner secondary air duct 9 and the outer secondary air duct 10 in a swirling manner. Accordingly, the swirl intensity of the air flow is selectively adjusted by either selectively adjusting a regulating angle of the outer secondary air vane 5 or selectively adjusting a position of the outer secondary air vane 5 within the outer secondary air duct 10 , so as to adjustably control the magnitude of the central recirculation zone. [0024] As shown in FIGS. 2 and 5 , the outer secondary air vane 5 comprises a set of flat vane blades 14 and a regulator 15 to selectively adjust the regulating angle of each of the flat vane blades 14 . Accordingly, each of the flat vane blades 14 has a straight planar configuration. Each of the flat vane blades 14 is coupled at the inlet wall of the outer secondary air duct 10 via the regulator 15 . Accordingly, the structural configuration of the outer secondary air vane 5 has a simple structure and is easy to adjust the swirl intensity of the air flow at the outer secondary air duct 10 . [0025] According to the preferred embodiment, the burner of the present invention is incorporated with a 1025 ton per hour B&WB-1025/18.3-M type boiler made by Babcock & Wilcox Beijing Co. Ltd, as an example. The combustion condition is shown as: lean coal as the pulverized coal, V daf =21.35%; A ar =29.42%; M t =7.1%; and Q net,ar =23162 kJ/kg, wherein V daf is the volatile matter as dry ash free, A ar is ash as received, M t is the moisture as received, and Q net,ar is the net heating value as received. By using 8 burners of the present invention at the bottom row of burners on the boiler, the amount of NOx emission is 1113 mg/m 3 (6% of O 2 ). In comparison with the same type boiler without using the burners of the present invention, the amount of NOx emission is 1206 mg/m 3 (6% of O 2 ). Therefore, a decrease of 8% of the amount of NOx emission is determined by incorporating the burner of the present invention with the boiler. [0026] The burner of the present invention is incorporated with a 670 ton per hour B&WB-670/13.7-M type boiler made by Babcock & Wilcox Beijing Co. Ltd, as another example. The combustion condition is shown as: low-grade coal as the pulverized coal, V daf =22.86%; A ar =35.28%; M t =7.4%; and Q net,ar =18130 kJ/kg, wherein V daf is the volatile matter as dry ash free, A ar is ash as received, M t is the moisture as received, and Q net,ar is the net heating value as received. By using 6 burners of the present invention at the bottom row of burners on the boiler, the amount of NOx emission is 795 mg/m 3 (6% of O 2 ). In comparison with the same boiler without using the burners of the present invention, the amount of NOx emission is 961 mg/m 3 (6% of O 2 ). Therefore, a decrease of 17.27% of the amount of NOx emission is determined by incorporating the burner of the present invention with the boiler. [0027] The burner of the present invention is incorporated with a 1025 ton per hour B&WB-1025/16.8-M type boiler made by Babcock & Wilcox Beijing Co. Ltd, as another example. The combustion condition is shown as: bituminous coal as the pulverized coal, V daf =33.15%; A ar =27.13%; M t =11.8%; and Q net,ar =17790 kJ/kg, wherein V daf is the volatile matter as dry ash free, A ar is ash as received, M t is the moisture as received, and Q net,ar is the net heating value as received. By using 8 burners of the present invention at the bottom row of burners on the boiler, the amount of NOx emission is 728 mg/m 3 (6% of O 2 ). In comparison with the same boiler without using the burners of the present invention, the amount of NOx emission is 843.55 mg/m 3 (6% of O 2 ). Therefore, a decrease of 13.74% of the amount of NOx emission is determined by incorporating the burner of the present invention with the boiler. [0028] Accordingly, the operation of the burner of the present invention is shown as the following. The flow of air-coal mixture is injected into the furnace through the primary air-coal mixture duct 1 , wherein the primary air-coal mixture conical outlet 11 is coupled at the outlet of the primary air-coal mixture duct 1 at a position close to the furnace. The pulverized coal separator 2 is supported within the primary air-coal mixture duct 1 , wherein the diameter of the pulverized coal separator 2 is gradually reducing towards the outlet of the primary air-coal mixture duct 1 . In addition, the outlet of the pulverized coal separator 2 , which is the opening having a smaller diameter, is alignedly pointing towards the furnace. After the flow of air-coal mixture passes through the pulverized coal separator 2 , the flow of air-coal mixture is partitioned into two portions. The inner central portion of the flow of air-coal mixture is the high-dense pulverized coal region while the outer peripheral portion of the flow of air-coal mixture is the less-dense pulverized coal region. The two portions of the flow of air-coal mixture are injected into the furnace through the primary air-coal mixture conical outlet 11 . The secondary air flow passes through the secondary air wind box 3 to the inner secondary air duct 9 and the outer secondary air duct 10 , wherein the secondary air flow is regulated to be swirled along the inner secondary air duct 9 and the outer secondary air duct 10 via the inner air vane 4 and the outer secondary air vane 5 respectively. It is worth to mention that the swirling direction of the secondary air flow at the inner secondary air duct 9 is the same as the swirling direction of the secondary air flow at the outer secondary air duct 10 . The secondary air flow is then injected into the furnace through the inner secondary air conical outlet 12 and the outer secondary air conical outlet 13 . Therefore, a moderate central recirculation zone is formed within the furnace to stabilize the combustion of the air-coal mixture. [0029] One skilled in the art will understand that the embodiment of the present invention as shown in the drawings and described above is exemplary only and not intended to be limiting. [0030] It will thus be seen that the objects of the present invention have been fully and effectively accomplished. The embodiments have been shown and described for the purposes of illustrating the functional and structural principles of the present invention and is subject to change without departure from such principles. Therefore, this invention includes all modifications encompassed within the spirit and scope of the following claims.

A burner includes a primary air-coal mixture duct coaxially extended through a secondary air wind box, a pulverized coal separator supported within the primary air-coal mixture duct, a secondary air duct including an inner secondary air duct and an outer secondary air duct coaxially formed around the primary air-coal mixture duct, a primary air-coal mixture conical outlet coupled with the outlet of the primary air-coal mixture duct, and inner secondary air and outer conical outlets coupled with the outlets of the inner secondary air and outer secondary air ducts respectively. The conical outlets are arranged to delay the mixing time of the primary air-coal mixture and secondary air flows through the primary air-coal mixture and secondary air ducts and to prolong the residence time in the center recirculation zone under the reduction ability so as to effectively reduce the formation of NOx.

BACKGROUND TO THE INVENTION [0001] This invention relates to the production of a mineral melt by burning combustible material in the presence of inorganic particulate material and thereby forming a melt. The melt is then fiberised to form mineral fibres. [0002] Traditionally, the normal way of producing a melt for slag, stone or rock fibres has been by means of a shaft furnace in which a self-supporting stack of inorganic particulate material is heated by combustion of combustible material in the furnace. The stack gradually melts and is replenished from the top, with melt draining down the stack and out from the bottom of the furnace. The normal furnace for this purpose is a cupola furnace. [0003] It is necessary for the stack to be self-supporting and permeable to the combustion gases, which are generally generated by combustion of carbonaceous material in the stack. It is therefore necessary that everything in the stack is relatively coarse (in order that the stack is permeable) and has high physical strength and does not collapse until combustion or melting is well advanced. In practice this means that the carbonaceous material is coke and the particulate material is either coarsely crushed rock, stone or slag or is in the form of briquettes formed from fine particulate material. [0004] Accordingly, if the material which is available is only available in finely divided form, it is necessary to incur the expense and inconvenience of forming it into briquettes. Briquetting usually uses sulphur-containing materials as binder, such as Portland cement with gypsum, and this means that the effluent is liable to have a high sulphur content, which has to be treated. [0005] The cupola or other stack furnace system also has the disadvantage that conditions in the furnace always tend to be sufficiently reducing that some of the iron is reduced to metallic iron. This necessitates separating metallic iron from the melt, reduces wool production, leads to the provision of iron waste and also tends to incur the risk of corrosion in the zone containing iron and slag. [0006] Another disadvantage is that the process does not have high thermal efficiency. [0007] Despite these disadvantages, the process using a cupola or other stack furnace has been widely adopted throughout the world for the manufacture of rock, stone or slag fibres. [0008] An alternative and entirely different system for the production of a mineral melt that avoids or reduces the disadvantages of the cupola system is disclosed in our earlier publication WO 03/002469. This system involves suspending powdered coal, or other fuel, in preheated combustion air and combusting the suspended fuel in the presence of suspended particulate mineral material in a circulating combustion chamber, i.e., a combustion chamber in which the suspended particulate materials and air circulate in a system which is or approaches a cyclone circulation system. This is commonly referred to as a cyclone furnace. [0009] The suspension of coal in preheated air, and the particulate mineral material, are introduced through the top or close to the top of the combustion chamber. Within the combustion chamber, combustion of the particulate coal occurs and the particulate material is converted to melt. The melt and particulate material that is not yet melted is thrown onto the walls of the chamber by the circulating gases and will flow down the chamber. [0010] In WO03/002469, the combustion chamber preferably leads downwards into a large settling tank which has a considerably enhanced volume. There may be a gas burner or other means for supplying extra energy to the settling tank to raise the temperature of the exhaust gases. The burner is positioned towards the top of the settling tank. The exhaust gases which are free of melt are taken from the settling tank or the combustion chamber up through a duct at the top of the chamber. [0011] In order to increase the energy efficiency of the cyclone furnace in WO03/002469, the exhaust gases, which leave the circulating chamber at a temperature in the range of 1400 to 1700° C. are used to preheat the particulate material so as to use rather than waste this heat energy. This step can be carried out under conditions which reduce nitrogen oxides (NOx) which reduces the environmental effects of the exhaust gases. The exhaust gases then pass through another heat exchanger by which there is indirect heat exchange with the combustion air. [0012] The cyclone furnace has significant advantages compared to cupola or other stack furnaces. With respect to fuel, it avoids the need for briquetting fine particles and a wide range of fuels can be used including, for example, plastic. Using a melting cyclone furnace eliminates the risk of reduction of the ores to iron and releases exhaust gases which are environmentally acceptable. The flexibility in melt capacity is much better than with a cupola furnace meaning that production can easily and quickly be switched, from, for example, 40% to 100% of total capacity so the time taken to respond to changing demand is greatly reduced. Furthermore, melting in a cyclone furnace is much quicker than is the case for a cupola furnace and is in the order of minutes, rather than in the order of hours. [0013] Hence, using a melting cyclone furnace system is economically and environmentally desirable and the system disclosed in WO 03/002469 works well. There is, however, room for improvement in the process. [0014] In processes for making mineral fibres, such as that in WO03/002469, the temperature and associated viscosity of the melt is extremely important as it has a direct effect on the quality of the mineral fibres produced. The purity is also important. In the system of WO03/002469 there are no means for controlling the temperature of the melt leaving the settling tank so this may vary which, without further treatment, will mean that the quality of the melt will vary. [0015] Furthermore, although in WO03/002469 several steps are taken to recycle the large amount of energy used in producing the melt, there is inevitably a large amount of energy that is lost due to the large volume of the settling tank and the high volume of combustion air which is used. It is desirable to increase the energy efficiency of the system further. [0016] WO03/002469 suggests a second embodiment shown in FIG. 2 in which the settling tank is replaced by a relatively small collection zone at the base of the combustion chamber. Such systems would lead to increased energy efficiency due to the reduced volume of the apparatus through which energy is lost. However, the inventors have found that in this system the melt quality is reduced, and is also subject to variations. [0017] U.S. Pat. No. 4,365,984 is also concerned with producing mineral wool using a melting cyclone furnace and involves feeding a particulate waste material containing inorganic non-combustible and organic combustible components into combustion air. As in WO03/002469, the system includes a large collection zone. In U.S. Pat. No. 4,365,984 the temperature of the melt is said to be important for fiberisation. This publication teaches that the melt temperature can be adjusted by adding additional reverts (mineral wool waste products) to the furnace with the fuel. [0018] Melting cyclones can be used to melt or treat mineral materials that are not subsequently used to make fibres. For example U.S. Pat. No. 4,544,394 concerns a method of melting glass in a vortex reactor and U.S. Pat. No. 6,047,566 concerns a method of melting recycled silicate materials. The temperature and hence viscosity of the melt is not a key factor in these processes. [0019] Melting cyclones are also known in other fields, particularly the field of pyrometallurgic processes (such as in U.S. Pat. No. 4,566,903 and U.S. Pat. No. 5,282,883). In such processes, the end product is a molten metal and any molten mineral material that is present is a waste material. Therefore, the quality of the mineral melt is unimportant in such processes. [0020] In US 2005/0039654, a cyclone chamber is used to combust fuel to generate energy for use for other purposes. Mineral material is not added to the system as the purpose is not to make a melt, but the fuel that can be used can be so-called “slagging coal” which contains some mineral materials that are not combustible but melt to form a slag when the coal is combusted. [0021] This publication is concerned with the selective use of oxygen enrichment at various points in the barrel of the cyclone combuster to maintain the slag in a molten form, to minimise NOx emissions and to minimise the escape of fine coal particles in the barrel. Air (referred to as a first or primary oxidant having an oxygen concentration of about 21% by volume) is introduced into the burner with the fuel. A second oxidant stream which has a concentration greater than the first can be introduced either into a region adjacent to the coal, or into the barrel. The second oxidant mixes with a portion (but not all) of the first oxidant to give a region of mixed oxidant which is said to contain less than about 31% oxygen by volume (so the oxygen level of the total oxidant i.e. combustion gas is much lower than 31%). [0022] There is no suggestion in this publication to increase the levels of oxygen further or to add fuel to the system, other than the coal which is added to the burner. [0023] The present invention is concerned with a method of making high quality mineral fibres in an energy efficient manner. SUMMARY OF THE INVENTION [0024] According to a first aspect, the present invention provides a method of method of making mineral fibres, comprising [0025] providing a circulating combustion chamber which comprises a top section, a bottom section and a base section, [0026] injecting primary fuel, particulate mineral material and primary combustion gas into the top section of the circulating combustion chamber and combusting the primary fuel thereby melting the particulate material to form a mineral melt and generating exhaust gases, [0027] separating the mineral melt from the exhaust gases wherein the exhaust gases pass through an outlet in the circulating combustion chamber and the mineral melt collects in the base section of the circulating combustion chamber, [0028] injecting secondary fuel and secondary combustion gas into the bottom section of the circulating combustion chamber to form a flame in the bottom section which heats the melt, and [0029] flowing a stream of the collected melt through an outlet in the base section to a centrifugal fiberising apparatus and forming fibres. [0030] According to a second aspect, the present invention provides an apparatus for use in a method of making mineral fibres according to the first aspect of the invention, comprising [0031] a circulating combustion chamber comprising a substantially cylindrical top section, a bottom section and a base section wherein the circulating combustion chamber comprises [0032] inlets in the top section for primary fuel, particulate mineral material and primary combustion gas, [0033] inlets in the bottom section for secondary fuel and secondary combustion gas, [0034] an outlet for exhaust gases, [0035] an outlet in the base section and [0036] centrifugal fiberising apparatus, wherein the outlet in the base section leads to the centrifugal fiberising apparatus. [0037] The method of the present invention essentially includes forming a flame in the bottom section of the combustion chamber. This is achieved by injecting a secondary fuel and a secondary combustion gas into the bottom section. Forming a flame in this section is highly advantageous as it is a mechanism by which the melt temperature can be changed. The secondary fuel can be all a solid fuel such as coal but preferably also comprises liquid or gaseous fuel. [0038] In the bottom section of the circulating combustion chamber the mineral melt flows down the walls to be collected in the base section. In this region the melt is present as a thin film on the walls of the chamber and as a bath in the base section, which is normally shallow. Hence, applying radiant heat in this area is particularly effective as it can penetrate the whole of the melt easily. Therefore, using a flame in this region is particularly effective at heating the melt homogeneously. It can also heat the melt rapidly and precisely so that by varying the flow rate of secondary fuel and secondary combustion gas, the temperature of the melt can be maintained within precise limits. [0039] In contrast, in prior art systems the temperature of the melt is not controlled in the chamber. Where the melt is not collected in the bottom of the chamber, but is collected in a separate (usually larger) tank, it would not be possible to achieve the effect of heating both the melt bath and the melt flowing down the walls of the chamber. [0040] As the chamber of the present invention incorporates the collection zone it is very compact and a high level of energy efficiency can be achieved as surface area losses are minimised. [0041] In the present invention the proportion of secondary fuel and secondary combustion gas can be manipulated to provide the desired results. When the oxygen provided in the secondary combustion gas is insufficient to enable the secondary fuel to undergo complete combustion (i.e., there is a sub-stoichiometric level of oxygen) the flame will be extended over a bigger volume than when sufficient gas to enable complete combustion is introduced with the secondary fuel. This can be advantageous as the flame can extend over a substantial proportion of the melt bath and therefore be extremely efficient at transferring radiant heat to it. [0042] In a further embodiment, when the primary fuel used is one, such as coal, which combusts in two stages, it is advantageous to introduce the secondary fuel and secondary combustion gas in proportions such that there is more than sufficient oxygen in the secondary combustion gas to enable the secondary fuel to undergo complete combustion. The excess oxygen acts to raise the oxygen levels in the bottom section of the chamber. This oxygen can help to increase the burn-out of particulate fuel such as coal which do not combust completely in one initial stage. [0043] Having excess oxygen in the bottom section is particularly important when the primary combustion gas is air which has been enriched with oxygen, or pure oxygen, as in this case the volume of gas is typically less and the concentration of the char particles is increased. Hence, fuel particles frequently do not have sufficient time to burn-out fully in the upper regions of the combustion chamber. [0044] A further means of enabling burn-out of char particles is the provision of a siphon outlet. This also promotes effective heating of the melt by the flame and prevents char particles from leaving the chamber in the melt. [0045] The present invention provides a simple but extremely effective way of controlling the temperature of the mineral melt, thereby enabling mineral fibres of a high quality to be made in an energy efficient and therefore environmentally friendly and cost effective manner. DETAILED DESCRIPTION [0046] The circulating combustion chamber in the present invention is of the type which is frequently referred to as a cyclone furnace. It has a top section, a bottom section and a base section. The construction of suitable cyclone furnaces is described in various patents including U.S. Pat. Nos. 3,855,951, 4,135,904, 4,553,997, 4,544,394, 4,957,527, 5,114,122 and 5,494,863. [0047] The chamber is generally vertically rather than horizontally inclined. It normally has a cylindrical top section, a frustoconical bottom section and a base section but can be wholly cylindrical. The base section is preferably an integral part of the chamber and can be simply the end part of the frustoconical bottom section or can be a cylindrical section at the end of the bottom section. [0048] The internal diameter of the base section is not larger than the internal diameter of the upper section, in contrast to traditional systems which often employ a tank at the base of the chamber of enhanced volume. [0049] An advantage of the invention, particularly in the preferred embodiment wherein oxygen enriched air or pure oxygen is used as the primary combustion gas, is that a compact combustion chamber can be used. Hence, it is preferred in the present invention that the combustion chamber is an integral chamber. By this, we mean that the chamber is not made up of different component parts which can be separated from one another. The ability to use compact furnaces compared to prior art systems minimises the surface area losses of energy from the furnace. [0050] The chamber volume is preferably less than about 25 m 3 , preferably less than about 20 m 3 or 15 m 3 , or even less than 10 m 3 . [0051] For example, to produce about 20 tons per hour of melt using 30% oxygen as the primary combustion gas, the volume of the circulating combustion chamber would need to be about 15 m 3 . In comparison, when using pure oxygen as the primary combustion gas, the chamber volume would only need to be about 5 m 3 . Therefore, when making use of the invention to allow the use of pure oxygen as the primary gas, a much smaller and hence much more energy efficient cyclone can be used for a particular throughput. [0052] The primary fuel and generally also the particulate mineral material and primary combustion gas are injected into the top section of the combustion chamber, which is usually cylindrical. The chamber has an outlet where hot exhaust gases can exit the chamber. This is preferably in the top section although it may be in the bottom section. In the top section the primary fuel combusts in the combustion gas and causes the particulate mineral material to melt. The mineral melt is then thrown against the sides of the chamber by the action of the circulating currents and flows down the sides of the chamber, due to the force of gravity, and collects in the base section of the chamber. The base section has an outlet for the mineral melt through which the melt passes as a stream and is then subjected to fiberisation in any conventional manner, for instance using a cascade spinner or a spinning cup or any other conventional centrifugal fiberising process. [0053] It is preferred that, at the point at which the outlet for mineral melt leaves the base section of the chamber, it does not immediately extend down but, instead, the outlet is a siphon. By a “siphon” we mean that the outlet, which is usually a tube or guttering, initially has an upward orientation relative to the opening in the chamber and subsequently has a downward orientation before leading to the fiberising equipment. [0054] As is normal with a siphon, the result is that, in order for the melt to leave the chamber, the melt bath inside the chamber must be deep enough to reach the vertically highest point of the siphon outlet. When this happens, gravity causes the melt to pass up through the upwardly oriented part of the siphon and then flow down the subsequent part of the siphon to the fiberising equipment. Hence, this creates an air-lock in the system which ensures that exhaust gases cannot escape from the base of the chamber. [0055] Using a siphon is particularly advantageous in the embodiment where a particulate fuel, such as coal, is used and leads to improvements in the melt quality. This is due to the fact that char particles, which are fuel particles that have not combusted completely in the top or bottom sections of the chamber, may collect on top of the melt pool and float there. These char particles are prevented from exiting the chamber with the melt by the siphon. [0056] By enabling the char particles to collect on the melt, their residence time in the chamber is increased compared to when a siphon is not used. Hence, the char particles can complete their combustion in the base zone to achieve full burn-out of the fuel. This ensures that the energy efficiency of the process is optimised. [0057] Burn-out in the base section of char particles floating on the melt is enhanced by the addition of secondary combustion gas into the bottom section of the circulating combustion chamber. [0058] A further advantage relates to the relative proportions of iron II and iron III in the melt. Traditionally, cupola furnaces have been used to make mineral melts which have a highly reducing atmosphere. As a result of this, almost all the iron oxide in melts produced by cupola furnaces is in the form of iron II. Iron II is good for the fire resistant properties of the fibres as it is converted to an iron III crystalline structure at high temperatures. [0059] However, cyclone systems such as that of the present invention are far more oxidising, particularly when the primary gas is oxygen enriched air. In this case, a substantial proportion of the iron in the melt can be in the form of iron III rather than iron II. When a siphon is used, the melt comes into contact with the char particles which are trapped floating on it. As the char particles are highly reducing, they act to reduce the iron III in the melt to iron II thereby ensuring good fire resistant properties for the fibres are maintained. [0060] The general motion of gases and suspended particulate material in the circulating combustion chamber is a cyclone motion. This is created by introduction of the primary combustion gas, as well as particulate fuel and mineral material, at an appropriate angle to sustain the swirling motion. The secondary combustion gas and fuel is also preferably introduced with the same directional momentum so as to sustain the circulating currents. [0061] In the bottom section of the circulating combustion chamber, which is normally frustoconical in shape, a secondary fuel which is liquid or gaseous and a secondary combustion gas is injected. [0062] The secondary fuel can be any fuel that undergoes combustion. [0063] In one embodiment, the secondary fuel comprises liquid or gaseous fuel and in particular can comprise any highly flammable liquid or gas. In this embodiment the secondary fuel can also comprise minor amounts (less than 50%, preferably less than 20% or 10% by energy) of solid or liquid particulate fuels which combust in a two stage process. These can be, for example, solid fuels such as coal or coke, or liquid fuels such as droplets of oil. As the less flammable component is included at a low level, it does not substantially affect the rapid and complete combustion of the secondary gas as a whole. In this embodiment, preferably the secondary fuel is selected from the group consisting of propane, methane, natural gas and alcohols, or mixtures thereof, optionally with a minor amount of coal or oil. [0064] In an alternative, and preferred embodiment, the secondary fuel comprises up to 100% of a solid fuel. This can be any carbonaceous material that has a suitable calorific value as noted below with respect to the primary fuel, but as with the primary fuel is preferably coal. In this embodiment, the secondary fuel preferably comprises 70 to 90% solid fuel. This embodiment has economic advantages as coal is less expensive than gaseous fuels such as natural gas. Using a solid fuel such as coal has also been found to result in reduced NOx formation. This is likely to be due to the fact that coal creates reducing conditions in the bottom of the chamber. [0065] In the most preferred embodiment, the secondary fuel comprises at least 50%, preferably 70 to 90% solid fuel such as coal with the remainder of the secondary fuel being liquid or gaseous fuel such as natural gas supplied through an oxy-fuel burner. [0066] The secondary combustion gas can be at ambient temperature or preheated and preferably comprises a higher level of oxygen than air, such as over 25% oxygen. It is usually oxygen enriched air or pure oxygen. When the secondary combustion gas is oxygen enriched air, it preferably comprises at least 30%, preferably at least 35%, more preferably at least 50% and most preferably at least 70% or even at least 90% oxygen by volume. The oxygen enriched air also comprises other gases that are present in air, such as nitrogen, and can comprise gases that are not normally present in air, such as inert gases or flammable gases such as propane or butane, provided that the total oxygen content is more than in air (which is around 21% by volume). In the most preferred embodiment the secondary combustion gas is pure oxygen. [0067] By “pure oxygen” we mean oxygen of 92% purity or more obtained by .e.g, the vacuum pressure swing absorption technique (VPSA) or it may be almost 100% pure oxygen obtained by a distillation method. [0068] In another embodiment, to optimise energy savings associated with the increased cost of oxygen compared to air, the gas comprises 30 to 50% oxygen. [0069] The secondary combustion gas and secondary fuel can be introduce separately into the bottom section, providing that sufficient mixing occurs to form a flame in the bottom section. Where the secondary fuel is a solid it can be introduced through a fuel feed pipe which has the same design as the primary fuel outlet. However, preferably the secondary combustion gas and secondary fuel are introduced together through at least one burner inlet, colloquially known as an oxy-fuel burner. This is particularly useful for the liquid of gaseous secondary fuels. The burner inlet or burner inlets are positioned in the lowest half of the bottom section of the circulating combustion chamber, preferably at the bottom of the bottom section, adjacent the base section so that the flame produced can heat the melt effectively. Preferably the flow rates of secondary combustion gas and secondary fuel are adjustable so the melt temperature can be changed as desired. [0070] Secondary gas inlets may be provided in addition to oxyfuel-burners, particularly in the embodiment where excess oxygen is added to the system. [0071] As noted above, the relative proportions of the secondary combustion gas and secondary fuel can be altered depending on the circumstances. [0072] In one embodiment the secondary fuel and secondary combustion gas are introduced in proportions such that there is insufficient oxygen in the secondary combustion gas to enable the secondary fuel to undergo complete combustion. For example, there can be 0.7, or 0.5 times the amount of oxygen in the secondary gas required to enable the secondary fuel to undergo complete combustion. This means that the flame has a tendency to be extended over a wide area. [0073] Typically, the bottom section of the chamber has some oxygen in the atmosphere but the levels are low. Consequently, the flame spreads more widely across the bottom zone than if the oxygen levels were higher. In this case a large flame is formed which can heat a larger area of the melt effectively. [0074] In a different embodiment, when the primary fuel used is one, such as coal, which combusts in two stages, it is advantageous to introduce the secondary fuel and secondary combustion gas in proportions such that there is more than sufficient oxygen in the secondary combustion gas to enable the secondary fuel to undergo complete combustion. The amount of oxygen is advantageously at least 1.3, preferably at least 1.5, more preferably at least 3 or 5 times the amount that would be required to enable the secondary fuel to combust completely. [0075] In general however, it is preferred that the secondary fuel and secondary combustion gas are added is equal stoichiometric proportions, so that the gas is sufficient just to enable complete combustion of the fuel. [0076] The primary fuel can be any combustible material and can be provided in any form. For, example, it can be a gas or liquid which is highly flammable and burns very quickly on entering the chamber, such as propane, methane, natural gas. The secondary fuel is present in a lower amount than the primary fuel and makes up less than 40%, typically 5 to 15% of the total fuel energy. [0077] However, the one embodiment where secondary combustion gas contains oxygen in a stoichiometric excess with regard to the secondary fuel, the primary fuel can be a particulate, such as coal, which combusts in a two-stage process. In the first stage, which is known as pyrolysis, the volatile compounds burn very quickly with rapid evolution of gas. This generates char particles which are rich in carbon. The second stage is combustion of the char particle which is much slower than the first stage. The second stage typically takes between 10 and 100 times longer than the first stage. Hence, while the first stage of combustion occurs almost instantaneously when a fuel particle enters a combustion chamber, the second stage does not normally occur unless the fuel has a significant residence time. If the fuel is incompletely combusted leaving some char in the melt, the melt quality will be reduced and may include bubbles or other discontinuities in the fibres produced. However, in the invention when excess oxygen is introduced into the bottom section, it increases the oxygen levels in the bottom section of the chamber so promotes rapid and complete combustion of the char particles. [0078] During use of the chamber, in this embodiment of the present invention, the chamber comprises an upper zone, a lower zone and a base zone. [0079] The upper zone is characterised in that pyrolysis, the initial stage of combustion of the particulate fuel, takes place. This corresponds broadly to the cylindrical top section of the chamber. The particulate fuel and preferably also the particulate mineral material and primary combustion gas are injected into the upper zone. The upper zone also includes an outlet through which hot gases pass. [0080] Pyrolysis of the fuel in the upper zone creates char, a carbon rich material. The char particles are generally thrown onto the surfaces of the chamber by the circulating gases and flow, with the melt, down the surfaces of the chamber under the action of gravity. [0081] The lower zone is characterised by the combustion of char. Hence, the lower zone generally corresponds to the frustoconical bottom section of the chamber, particularly the surfaces of the chamber in this section. Char particles may also be present on the surface of the top section of the chamber, and floating on the horizontal surface of the melt pool in the base zone. [0082] Hence the upper zone generally extends over the majority of the top section, of the chamber whereas the lower zone extends over the majority of the bottom section, particularly the surfaces of the bottom section of the chamber and may also extend to some extent on to the surfaces of the top section of the chamber. [0083] Typically in the lower region of a circulating combustion chamber of the type which has separation of gas at the top and melt at the bottom, oxygen levels are low, even if an excess of oxygen has been added in the upper region. Therefore, char in traditional systems needs a long residence time to burn in this region. In the present invention, secondary combustion gas is injected into the lower zone to aid the second stage of combustion, i.e., combustion of the char particle. Therefore, complete combustion of the fuel occurs in the lower zone in the method of the present invention. [0084] In this embodiment the primary particulate fuel can be in liquid or solid form. Where the primary fuel is a liquid, it is used in the form of droplets, i.e., particles of liquid fuel. In this embodiment, the fuel can be particles of oil or other carbon based liquids. [0085] However, the primary particulate fuel in the present invention is preferably solid. It is generally a carbonaceous material and can be any particulate carbonaceous material that has a suitable calorific value. This value can be relatively low, for instance as low as 10000 kJ/kg or even as low as 5000 kJ/kg. Thus it may be, for instance, dried sewage sludge or paper waste. Preferably it has higher calorific value and may be spent pot liner from the aluminium industry, coal containing waste such as coal tailings, or powdered coal. [0086] In a preferred embodiment, the primary fuel is powdered coal and may be coal fines but preferably some, and usually at least 50% and preferably at least 80% and usually all of the coal is made by milling lump coal, for instance using a ball mill. The coal, whether it is supplied initially as fines or lump, may be good quality coal or may be waste coal containing a high inorganic content, for instance 5 to 50% inorganic with the balance being carbon. Preferably the coal is mainly or wholly good quality coal for instance bituminous or sub-bituminous coal (ASTM D388 1984) and contains volatiles which promote ignition. [0087] The primary fuel particles preferably have a particle size in the range from 50 to 1000 μm, preferably about 50 to 200 μm. Generally at least 90% of the particles (by weight) are in this range. Generally the average is about 70 μm average size, with the range being 90% below 100 μm. [0088] The primary fuel can be fed into the chamber through a feed pipe in a conventional manner to give a stream of fuel particles. This normally involves the use of a carrier gas in which the fuel particles are suspended. The carrier gas can be air, pure oxygen enriched air or oxygen, preferably at ambient temperature to avoid flashbacks or a less reactive gas such as nitrogen. The feed pipe is preferably cylindrical. [0089] The particulate mineral material is any material that is suitable for making mineral fibres which can be glass fibres or rock stone or slag fibres. Glass fibres typically have a chemical analysis, by weight of oxides, of above 10% Na 2 O+K 2 O, below 3% iron as FeO, below 20% CaO+MgO, above 50% SiO 2 and below 5% Al 2 O 3 . Rock, stone or slag fibres typically have an analysis, by weight of oxides, of below 10% Na 2 O+K 2 O, above 20% CaO+MgO above 3% iron as FeO, and below 50% SiO 2 and, often, above 10% Al 2 O 3 . The mineral material can be waste materials such as mineral fibres which have already been used or which have been rejected before use from other processes. [0090] The particulate mineral material, which is melted in the chamber to produce the mineral melt, is introduced into the upper section of the chamber so that it becomes suspended in the gases therein. The point at which the particulate mineral material is added is not critical and it can be mixed with the fuel and injected through the fuel feed pipe. It is, however, preferable to add the particulate mineral material into the burning fuel. This can be achieved by adding the particulate mineral material into the chamber though an inlet in a conventional way, for example at or near to the top of the chamber. [0091] Primary combustion gas is introduced into the upper section of the chamber and can be at ambient temperature or can be preheated. When the gas is heated, the maximum desirable temperature that the primary combustion gas is pre-heated to is around 600° C., and the preferred preheating is to between 300 and 600° C., most preferably to around 500 to 550° C. The primary combustion gas can be any gas in which the fuel can combust, for example, air, air enriched with oxygen or pure oxygen. It can also include propane or methane. [0092] In the preferred embodiments the primary combustion gas contains at least 25% oxygen. It is preferably oxygen enriched air which comprises at least 30%, preferably at least 50%, most preferably at least 70% oxygen by volume or pure oxygen. The oxygen enriched air may comprise minor amounts of gases that are not typically present in air. [0093] Where pure oxygen is used it is preferably at ambient temperature, rather than being preheated. In this embodiment where the primary combustion gas is oxygen enriched air or pure oxygen, the total volume of primary combustion gas used can be much less than where air alone is used as the primary combustion gas, as only the oxygen is used for combustion. Hence, significant energy savings can be made through the use of oxygen enriched air or pure oxygen as the lower volume of combustion gas requires less energy to heat. Using oxygen enriched air or pure oxygen also means that the circulating combustion chamber can be smaller than when air is used. This also leads to energy savings. [0094] The primary combustion gas may be introduced through a feed pipe with the fuel suspended in it, especially when the gas is at a relatively low temperature. The fuel should not begin to combust in the fuel pipe before it enters the chamber (a phenomenon known as “flash back”) so low gas temperatures are needed in this embodiment. However, the primary combustion gas is preferably introduced separately through one or more combustion gas inlets which can be located in the vicinity of the fuel feed pipe so that the combustion gas is directed into the chamber in the same region as the fuel, to allow for efficient mixing. In the most preferred embodiment, the combustion gas inlet concentrically surrounds the feed pipe and the secondary gas inlet, as discussed below. [0095] Whether or not they are introduced together, the speed at which the combustion gas and the fuel are injected into the chamber is relatively low (preferably between 1 and 50 m/s), so as to minimise wear of the apparatus. When the fuel is suspended in the combustion gas, the speed is preferably between 5 and 40 m/s. When they are introduced separately, which is preferred, the injection speed of the fuel is preferably 20 to 40 m/s. [0096] It is desirable to ensure that the particulate fuel is mixed rapidly and thoroughly with the primary combustion gas as this ensures that the fuel is ignited rapidly so that it can undergo pyrolysis almost immediately after introduction into the chamber. Having thorough mixing also ensures that the residence time of the fuel particles in the primary combustion gas is more uniform thereby leading to more efficient fuel combustion. [0097] To help ensure rapid and thorough mixing in one embodiment of the invention an additional gas can be introduced in the upper zone which travels at a higher speed than the primary combustion gas and the particulate fuel and, due to the speed differential, causes turbulence of the stream of fuel particles thereby breaking up the stream and ensuring rapid mixing. The additional gas is generally much less voluminous than the combustion gas and typically makes it less than 40% of the total gas injected into the combustion chamber, preferably between 10 and 30%. The additional gas can be any gas including air, nitrogen, oxygen, or a flammable gas such as propane or butane. The additional gas may be injected from an inlet so that it is adjacent the stream of fuel particles in the chamber but is preferably injected to an inlet that concentrically surrounds the fuel inlet. This concentric arrangement leads to efficient mixing, particularly where the additional gas inlet has a converging nozzle at its opening. The additional gas is preferably travelling at least 100 m/s faster than the fuel and the combustion gas, usually at least 250 m/s, preferably at least 300 m/s. In the most preferred embodiment, the injection speed of the additional gas is sonic, i.e, at or above the speed of sound. FIGURES [0098] FIG. 1 is an illustration of apparatus which is suitable for use in a preferred embodiment of the present invention; [0099] FIG. 2 is a front view of the siphon which is shown in the dotted oval of FIG. 1 ; [0100] FIG. 3 is a side view of the siphon shown in the dotted oval of FIG. 1 . [0101] FIG. 1 shows a circulating combustion chamber 1 which comprises a top section 2 , a bottom section 3 and a base section 4 . Primary fuel and particulate material are introduced through inlet 5 with primary combustion gas being introduced through inlet 6 which concentrically surrounds inlet 5 . The primary fuel is ignited and burns in the upper section 2 and is collected in the base section 4 as a melt pool 7 . The hot exhaust gases pass through the flue gas outlet 8 at the top of the combustion chamber. Secondary fuel and secondary combustion gas are injected through an oxy-fuel burner 9 and form a flame in the bottom region 3 which acts to heat the melt pool 7 . Further secondary combustion gas is introduced through oxygen inlets 10 in the bottom region 3 which aids burn-out of the fuel in this region. The melt flows through siphon 11 to fiberising equipment 12 where it is formed into fibres. [0102] FIG. 2 shows a front view of the siphon 11 with a stream of melt 13 exiting the siphon 11 . [0103] FIG. 3 shows a cross-section of the siphon 11 which has a part which is upwardly oriented 14 and rises vertically above the opening 15 in the chamber 1 . Once the melt bath 7 gets above the level of the vertically oriented part 14 , the melt flows over that part as stream 13 . EXAMPLE [0104] The inventors have demonstrated that providing fuel as secondary fuel into the bottom section of the circulating combustion chamber is a very efficient way to increase the melt temperature. In the tests performed, the total amount of fuel energy (primary and secondary) into the cyclone was increased by 2%. The extra fuel was added as secondary fuel provided at the bottom of the chamber. The amount of primary fuel was kept constant. This led to an increase in the melt temperature of 40-50° C. [0105] To achieve the same temperature rise of the melt in a cupola furnace, much more than 2% extra energy would be needed. [0106] The high efficiency of the present invention is due to the fact that adding fuel energy in the bottom section can rapidly and efficiently heat the thin layer of melt running down the sides of the chamber and in the base of the chamber.

The present invention relates to a method of making mineral fibres, comprising providing a circulating combustion chamber ( 1 ) which comprises a top section ( 2 ), a bottom section ( 3 ) and a base section ( 4 ), injecting primary fuel, particulate mineral material and primary combustion gas into the top section of the circulating combustion chamber and combusting the primary fuel thereby melting the particulate material to form a mineral melt and generating exhaust gases, separating the mineral melt from the exhaust gases wherein the exhaust gases pass through an outlet ( 8 ) in the circulating combustion chamber and the mineral melt collects in the base section of the circulating combustion chamber, injecting secondary fuel, which comprises liquid or gaseous fuel, and secondary combustion gas into the bottom section of the circulating combustion chamber to form a flame in the bottom section which heats the melt, and flowing a stream of the collected melt through an outlet ( 15 ) in the base section to a centrifugal fiberising apparatus and forming fibres. The present invention also provides an apparatus for use in the method of the invention.

FIELD OF THE INVENTION The present invention relates to improvements in the field of minimal access lumbar posterior surgery and more particularly to instrumentation which allows for maximal access to the surgical field through the smallest possible incision. Greater access is allowed into the working field while enjoying the reduction of trauma and disturbance to surrounding tissues, which results in a reduced the time necessary to complete the operative procedure, increased safety of the procedure, and increased accuracy by providing an expanded working field. BACKGROUND OF THE INVENTION Microscopic Lumbar Diskectomy techniques were developed and championed by Dr. Robert Williams in the late 1970's and by Dr. John McCullough in the late 1980's and 1990's. For the first time since the advent of Lumbar Disc Surgery by Mixter and Barr in 1934 a method was introduced allowing Lumbar Disc Surgery to be performed through a small incision safely resulting in faster patient recovery and converting a two to five hospital stay procedure virtually to an outpatient procedure. The special retractors developed by Drs. Williams and McCullough however were often difficult to maintain in optimum position and relied on the interspinous and supraspinatus ligaments for a counter fixation point severely stretching the structures. This stretching along with the effects of partial facectomy, diskectomy, removal of the ligamentum flavum and posterior longitudinal ligament contributed to the development of Post Diskectomy Instability. Taylor retractors were also used but were cumbersome, required larger incisions and often injured the facet joints. Dr. William Foley in 1997 introduced a tubular system mated to an endoscope which he labeled a Minimal Endoscopic Diskectomy (MED) system. It featured sequentially dilating the Lumbar Paraspinous Muscles allowing a working channel to be advanced down to the level of operation through which nerve root decompression and Diskectomy Surgery could be performed with a small incision and less muscle trauma. Improvements were made by Dr. Foley in his second generation METRx system. However, there were several disadvantages to the MED and METRx systems. In the MED and METRx systems, the cylindrical working channel considerably restricted visualization and passage of instruments. It also compromised the “angle of approach” necessary for safe usage of the operating instruments. This problem was proportionately aggravated with the long length of the tube. This compromised visualization contributed to the following problems, including nerve injury, dural tear, missed disc fragments, inadequate decompression of the lateral recess, increased epidural bleeding, difficulty controlling epidural bleeding, inadequate visualization of the neuroforamen, and inadequate decompression of neuroforamen. The repetitive introduction of successively larger dilators caused skin abrasion with the potential for carrying superficial skin organisms down to the deeper tissue layers hypothetically increasing the risk of infection. The learning curve for operating in a two dimension endoscopic field proved to be arduous and contributed to the above complications. The attempted use of the METRx system for more complex procedures such as fusion was further hazardous by inherent limitations. Endius in September of 2000 then introduced a similar device which differed by having an expandable foot piece to allow greater coverage of the operative field. However, the enlarged foot piece was unwieldy and difficult to seat properly. Exposure of the angle of approach was also limited by having to operate through a proximal cylindrical tube with its limitations as described before. In comparison to the METRx system the working area was improved but access was again restricted by the smaller proximal cylinder. Both systems offered endoscopic capability but many spine surgeons chose to use an operating microscope or loupes to maintain 3-Dimensional visualization rather than the depth impaired 2-Dimensional endoscopic presentation. Keeping debris off of the endoscopic lens has also proved to be a troubling challenge. SUMMARY OF THE INVENTION The system and method of the invention, hereinafter minimal incision maximal access system, includes a surgical operating system that allows for maximum desirable exposure along with maximum access to the operative field utilizing a minimum incision as small as the METRx and Endius systems. The minimal incision maximal access system disclosed offers advantages over the METRx and Endius systems in several respects. First, instead of multiple insertions of Dilating Tubes the Invention is a streamlined single entry device. This avoids repetitive skin surface entry. Second, the minimal incision maximal access system offers the capability to expand to optimum exposure size for the surgery utilizing hinged bi-hemispherical or oval Working Tubes applied over an introducer Obturator which is controllably dilated to slowly separate muscle tissue. Third, the minimal incision maximal access system maximizes deeper end working and visualization area with maximum proximal access and work dimensions significantly greater than either the METRx or Endius devices and methods. Fourth, the minimal incision maximal access system provides expanded visual and working field to makes the operative procedure safer in application and shorten the surgeons's learning curve because it most closely approximates the open microdiskectomy techniques. Fifthly, the minimal incision maximal access system has a tapered ended Obturator which allows for tissue spread rather than muscle tissue tear and subsequent necrosis. Sixth, the minimal incision maximal access system controls muscle oozing into the operative field which is controlled by simply opening the tubes further. This also thereby controls the bleeding by pressure to the surrounding tissues. Seventh, in contrast to the cylindrical tube based systems such as the METRx and Endius the minimal incision maximal access system offers a larger working area in proportion to the working depth. For the first time this allows for a minimal access technique to be applied to the large or obese patients. The enlarged footprint of the longer tubes in the minimal incision maximal access system is a major difference from any other minimal access system. An eighth advantage of the minimal incision maximal access system is that ist expandable design allows for excellent exposure for more complex procedures such as fusion and instrumentation including TLIF, PLIF, and TFIF (Transfacet Interbody Fusion), as well as allowing application for anterolateral lumbar disc surgery. The minimal incision maximal access system can also be used for cervical surgery posteriorly (foraminotomy, lateral mass instrumented fusion) as well as anterior cervical diskectomy and fusion. The minimal incision maximal access system can also be used for anterior lumbar interbody fusion be it retroperitoneal, transperitoneal or laparoscopic. A ninth advantage of the minimal incision maximal access system is that the medial oval cutout of the retractors, or sleeve forming the working tube, allows more central docking on the spine which is problematic for other devices. A medialized docking provides access for easier and better and safer dural retraction to address midline pathology. A tenth advantage is had by including an anti-reflective inner surface of the retractor sleeves which eliminates unwanted glare. An eleventh advantage of the minimal incision maximal access system includes the slanted and contoured distal end of the retractor sleeve which allows minimal resistance for entry and advancement to the docking site. A twelfth advantage minimal incision maximal access system is the provision of a variety of retractor tips specific for different surgical procedures. A thirteenth advantage of the minimal incision maximal access system is the provision of oval retractor sleeves for larger access requirements such as pedicle to pedicle exposure and especially in the case where pedicle screw instrumentation is to be applied. This minimizes unnecessary muscle spread by providing a smaller waist profile than a circular system. A fourteenth advantage of the minimal incision maximal access system is that the larger retractor sleeve also features one or two “skirts” to cover the lateral aperture created by the spread of the two retractor sleeves when opened. This prevents soft tissue and muscle ingress into the working cone. The skirts are attached to the working tube either at the hinge or on one of the two halves of the sleeve. A fifteenth advantage of the minimal incision maximal access system is the provision of a modular design in which the retractor sleeves can be quickly removed, changed and reapplied. In this version the proximal port can also be modular and changeable to fit the needs of a specific surgical procedure. A sixteenth advantage of the minimal incision maximal access system is that the retractor sleeves can be made out of metal, ceramic or plastic, can be opaque or translucent, and can have tips of different shapes for different applications. A seventeenth advantage is the provision of snap lock connections of the major parts of the Invention provides for easy assembly and disengagement for cleaning and sterilization purposes. Further, the Obturator is cannulated for carrying a central Guide Pin Passage. It has a Handle component which remains superficial to the skin. The obturator houses an internal hinge device which allows for spread of the two obturator tips. BRIEF DESCRIPTION OF THE DRAWINGS The invention, its configuration, construction, and operation will be best further described in the following detailed description, taken in conjunction with the accompanying drawings in which: FIG. 1 is a perspective view of a working tube with an angled upper section and shown in position with respect to an obturator insertable into and workable within the working tube; FIG. 2 is a perspective assembled view illustrating the relative positions of the obturator and working tube; FIG. 3 is a perspective assembled view illustrates the position of the obturator after it has been inserted into the working tube; FIG. 4 is a view taken along line 4 — 4 of FIG. 2 and looking into the working tube of FIG. 1 ; FIG. 5 is a sectional view taken along line 5 — 5 of FIG. 2 and looking into the hinge of working tube of FIG. 1 , illustrating its hinge connections; FIG. 6 is an side end view of the working tube of FIGS. 1 -and illustrating predominantly one of the rigidly connected halves of the invention; FIG. 7 is a side sectional view taken along line 7 — 7 of FIG. 6 and showing the internal bearing pivot; FIG. 8 is a side sectional view taken along line 8 — 8 of FIG. 5 and illustrating a option for external bevel for the working tube; FIG. 9 is a side view of the working tube of FIGS. 1-8 shown with the lower portions in parallel alignment and the upper portions angled with respect to each other; FIG. 10 is a side view of the working tube as seem in FIG. 9 and shown with the lower portions in an angled relationship and the upper portions in a closer angled relationship with respect to each other; FIG. 11 is a side view of the working tube as seen in FIGS. 9 and 10 and shown with the lower portions in a maximally angled relationship and the upper portions in parallel alignment signaling maximal spread of the lower portions in bringing the upper portions into parallel alignment; FIG. 12 is a side view of the obturator of FIG. 1 and seen in an assembled view and emphasizing a through bore seen in dashed line format; FIG. 13 is a side view of the obturator of FIG. 11 as seen in an assembled view but turned ninety degrees about its axis and emphasizing the through bore; FIG. 14 shows a side view of the obturator 33 of FIG. 13 with the spreading legs in an angled apart relationship; FIG. 15 is a sectional view taken along line 14 — 14 of FIG. 12 and gives a sectional view from the same perspective seen in FIG. 14 ; FIG. 16 is a view of the obturator similar to that seen in FIG. 15 , but turned ninety degrees along its axis and illustrates the wedge as having a narrower dimension to lend internal stability; FIG. 17 is a closeup view of the external hinge assembly seen in FIG. 1 and illustrates the optional use of a plug to cover the exposed side of a circular protrusion; FIG. 18 is a view taken along line 18 — 18 of FIG. 11 and illustrates the use of an optional skirt having flexible members which spread from an initial curled position to a straightened position to better isolate the surgical field; FIG. 19 is a view of the lower tube hemicylindrical portions 65 and 69 in a close relationship illustrating the manner in which the skirts sections within their accommodation slots areas; FIG. 20 is a cross sectional view of the a patient and spine and facilitates illustration of the general sequence of steps taken for many procedures utilizing the minimal incision maximal access system disclosed; FIG. 21 illustrates a fascial incisor overfitting a guide pin and further inserted to cut through external and internal tissue; FIG. 22 illustrates the assembled Working Tube-Obturator being inserted into the area previously occupied by the fascial incisor and advanced to the operative level lamina; FIG. 23 illustrates the obturator 33 being actuated to a spread orientation to which automatically actuates the working tube to a spread orientation; FIG. 24 is a view of the working tube 35 is in place and supported, held or stabilized in the field of view by a telescopy support arm and engagement, the opposite end of the stabilizing structure attached to the operating table; FIG. 25 illustrates further details of the support arm seen in FIG. 24 , especially the use of a ball joint; FIG. 26 illustrates a side view of the assembly seen in FIG. 25 is seen with an adjustable clamp operable to hold the working tube open at any position; FIG. 27 is a top view looking down upon the adjustable clamp seen in FIGS. 25-26 and shows the orientation of the working tube and adjustable clamp in fully closed position; FIG. 28 shows a variation on the obturator seen previously in FIG. 1 and illustrates the use of handles which are brought together; FIG. 29 illustrates a further variation on the obturator seen previously in FIG. 1 and illustrates the use of a central ball nut; FIG. 30 is a sectional view taken along line 30 — 30 of FIG. 29 and illustrates the use of a central support block to support the central threaded surface; FIG. 31 is a top view of a thin, inset hinge utilizable with any of the obturators herein, but particularly obturators of FIGS. 1 and 29 ; FIG. 32 is a sectional view of the obturator of FIG. 1 within the working tube of FIG. 1 with the wedge 51 seen at the bottom of an internal wedge conforming space; FIG. 33 illustrates the obturator seen in FIG. 32 as returned to its collapsed state. FIG. 34 illustrates a top and schematic view of the use of a remote power control to provide instant control of the working tube using an adjustable restriction on the upper angled hemicylindrical portions of the working tube; FIG. 35 is a view taken along line 35 — 35 of FIG. 34 and illustrating the method of attachment of the cable or band constriction; and FIG. 36 is a mechanically operated version of the nut and bolt constriction band seen in FIG. 25 . DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The description and operation of the minimal incision maximal access system will be best described with reference to FIG. 1 and identifying a general system 31 . System 31 includes an obturator 33 and a working tube 35 . The orientation of the obturator 33 is in a slightly displaced from a position of alignment with the working tube 35 for entry into working tube 35 and to provide the initial carefully controlled force for spreading the working tube 35 , as will be shown. Obturator includes an upper control housing 37 and a pair of spreading legs 39 and 41 . The spreading legs 39 and 41 are seen as coming together to form a conical tip and thus have hemi conical end portions. The spreading legs 39 and 41 overfit attachment leg portions 43 and 45 , respectively. At the top of the upper control housing 37 a boss 47 surrounds and supports the extension of a control shaft 49 . A knurled thumb knob 50 sits atop the control shaft 49 to facilitate controlled turning of the control shaft 49 to control the degree of spreading of the spreading legs 39 and 41 . Thus spreading can be controlled independently of pressure applied along the length of the obturator 33 . Below the upper control housing 37 is the bottom of the control shaft 49 which operates against a wedge 51 . The wedge 51 operates within a pair of opposing slots 52 in an upper portion 53 of the overfit attachment leg portions 43 and 45 . The lower ends of the overfit attachment leg portions 43 and 45 include insertion tangs 55 which fit within insertion slots 57 of the spreading legs 39 and 41 . The overfit attachment leg portions 43 and 45 are pivotally attached to the upper control housing 37 internally by pivot blocks 59 which fit within access apertures 60 . The working tube 35 has a first lower extending connection tang 61 and a second lower extending connection tang 63 . First lower extending connection tang 61 connects into a slot 64 of a lower tube hemicylindrical portion 65 . The first lower extending connection tang 61 is fixed to an upper angled hemicylindrical portion 67 . The second lower extending connection tang 63 connects into a slot 68 of a lower tube hemicylindrical portion 69 . Second lower extending connection tang 61 is fixed to and an upper angled hemicylindrical portion 71 . The upper angled hemicylindrical portion 67 has a reinforced wear plate 73 for applying upper pressure and force on the upper angled hemicylindrical portions 67 and 71 toward each other to cause the first and second lower extending connection tangs 61 & 63 and their connected lower tube hemicylindrical portions 65 and 69 to be urged away from each other. At the side of the working tube 35 at the transition between the upper angled hemicylindrical portions 67 and 71 and a point just above the first and second lower extending connection tangs 61 & 63 is an external hinge assembly 77 . Hinge assembly 77 may include an optional first guide plate 79 and first circular protrusion 81 attached to upper angled hemicylindrical portions 67 , and a first slotted plate 83 positioned adjacent to first guide plate 79 and having a slot partially surrounding the circular protrusion 81 . Upper angled hemicylindrical portion 71 has a pair of spaced apart facing surfaces facing a matching pair of facing surfaces of the upper angled hemicylindrical portion 67 , of which a dividing line 85 is seen. Upper angled hemicylindrical portions 67 and 71 are be brought together to cause the first and second lower extending connection tangs 61 & 63 and their connected lower tube hemicylindrical portions 65 and 69 to spread apart. In the View of FIG. 1 , the first and second lower extending connection tangs 61 & 63 are shown in a spread apart relationship. A locking pin 87 is seen which can be used to engage angularly spaced apart apertures in the circular protrusion 81 to provide a detent action to hold the working tube 35 in various degrees of spread. Also seen is a slight exterior bevel 89 on the lower tube hemicylindrical portions 65 and 69 . Note the angled separation of the upper angled hemicylindrical portions 67 and 71 and exposing opposing surfaces 91 . The angle of the opposing surfaces 91 equals the angle of spread of the first and second lower extending connection tangs 61 & 63 . Referring to FIG. 2 , a perspective assembled view illustrates the relative positions of the obturator 33 and working tube 35 in a position for the obturator 33 to be inserted into the working tube 35 and before any spreading takes place. Referring to FIG. 3 , a perspective assembled view illustrates the position of the obturator 33 after it has been inserted into the working tube 35 and again before any spreading takes place. Note that the pivot axes of the first and second lower extending connection tangs 61 & 63 are on par with the pivot axes of the insertion tangs 55 . The tip of the obturator 33 extends slightly beyond the bottom most part of the working tube 35 so that the completed assembly can be smoothly urged past muscle and other tissue. Referring to FIG. 4 , a view taken along line 4 — 4 of FIG. 1 is a view looking down into the working tube 35 . Other features seen include a wear plate 93 located on the upper angled hemicylindrical portion 71 . In both of the wear plates 73 and 93 a universal port 94 is provided as a bore for insertion of a tool or lever to assist in bringing the upper angled hemicylindrical portions 67 and 71 into a tubular relationship. Further, an identical hinge assembly 77 on the side opposite that seen in FIG. 1 is shown with the same numbering as the components which were seen in FIG. 1 . Also seen are a pair of opposing surfaces 95 on upper angled hemicylindrical portion 71 and a pair of opposing surfaces 97 on upper angled hemicylindrical portion 67 . Also seen is a central working aperture 99 . Referring to FIG. 5 , a view taken along line 5 — 5 of FIG. 1 is a sectional view looking down into the working tube 35 . The connectivity of the structures seen in FIG. 4 are emphasized including the connection of circular protrusion 81 to the upper angled hemicylindrical portion 71 , and the connection of first slotted plate 83 to upper angled hemicylindrical portion 67 , and which is indicated by the matching section lines Further, an identical hinge assembly 77 on the side opposite that seen in FIG. 1 is shown with the same numbering as the components which were seen in FIG. 1 . Referring to FIG. 6 , a view of one end of the working tube 35 illustrates predominantly the second angled half portion 63 . Elements seen in FIGS. 1 and 2 are made more clear in FIG. 3 . Referring to FIG. 7 , a side sectional view taken along line 7 — 7 of FIG. 6 and shows the internal bearing pivot consisting of a slightly greater than hemispherical side bump projection 101 located on upper angled hemicylindrical portion 71 , and a slightly less than hemispherical side circular groove 103 located on upper angled hemicylindrical portion 67 . Also seen is the interconnect slots 64 and 68 as well as the first and second lower extending connection tangs 61 and 63 . In the showing of FIG. 7 an external bevel 105 is utilized Referring to FIG. 8 , a side semi-sectional view taken along line 8 — 8 of FIG. 5 illustrates the integral connectivity of circular protrusion 81 with the upper angled hemicylindrical portion 71 . Seen for the first time in isolation are a pair of pin apertures 107 for engaging the locking pin 87 . Referring to FIG. 9 , an illustration of a side plan view and in which the lower tube hemicylindrical portions 65 and 69 are in matching straight alignment and forming a lower tube shape, while the upper angled hemicylindrical portions 67 and 71 are angled apart. Referring to FIG. 10 , a midpoint of movement is illustrates wherein the lower tube hemicylindrical portions 65 and 69 have begun to move apart widening the lower tube shape previously formed into an angled apart opposing hemicylindrical shape, while the upper angled hemicylindrical portions 67 and 71 are brought closer together to have a closer though angled apart an angled apart opposing hemicylindrical shape. Referring to FIG. 11 , a completed movement, with respect to the view of FIG. 4 illustrates a state where the lower tube hemicylindrical portions 65 and 69 have moved apart to their maximum extent into a maximally angled apart opposing hemicylindrical shape, while the upper angled hemicylindrical portions 67 and 71 are brought completely together to form an upper tube shape. It is the position of FIG. 6 which is the ideal working position once the lower tube hemicylindrical portions 65 and 69 are within the body, and provides an expanded working field at the base of the working tube 35 . Surgical work is ideally performed through the upper, abbreviated axial length tube shape formed by the upper angled hemicylindrical portions 67 and 71 . Referring to FIG. 12 , a side view of the obturator 33 of FIG. 1 is seen in an assembled view and emphasizing in dashed line format a through bore 111 which extends though the obturator 33 from the knurled knob 50 through to the tip of the pair of spreading legs 39 and 41 . Referring to FIG. 13 , a side view of the obturator 33 of FIG. 11 is seen in an assembled view but turned ninety degrees about its axis, and agin emphasizing in dashed line format the through bore 111 which extends though the obturator 33 from the knurled knob 50 through to the tip of the pair of spreading legs 39 and 41 . It is from this position that further actuation will be illustrated. Referring to FIG. 14 , a side view of the obturator 33 of FIG. 13 is seen but with the spreading legs 39 and 41 in an angled apart relationship. An optional support 112 is supported by the upper control housing 37 to enable independent support and locationing of the obturator 33 should it be needed. Once the knurled knob 50 is turned, the wedge 51 seen in FIG. 1 is driven downward causing the spreading of the spreading legs 39 and 41 . Referring to FIG. 15 , a sectional view taken along line 14 — 14 of FIG. 12 gives a sectional view from the same perspective seen in FIG. 14 . Pivot blocks 59 are seen as having pivot bores 113 which enable the upper portions 53 to pivot with respect to the upper control housing 37 and which enable the downward movement of the wedge 51 to translate into a spreading of the spreading legs 39 and 41 . As can be seen, the knob 50 and control shaft 49 and the wedge 51 have the through bore 111 . In the configuration shown, the control shaft 49 includes a threaded portion 113 which engaged an internally threaded portion 115 of an internal bore 117 of the upper control housing 37 . The boss 47 is shown to be part of a larger insert fitting within a larger fitted bore 119 within the upper control housing 37 . This configuration pushes the wedge 51 downwardly against an internal wedge conforming space 123 to cause the insertion tangs 55 and upper portions 53 to spread apart. The wedge conforming space 123 need not be completely wedge shaped itself, but should ideally have a surface which continuously and evenly in terms of area engages the wedge 51 to give even control. Further, the wedge 51 can be configured to be rotatable with or independently rotationally stable with respect to the control shaft 49 . As can be seen, the through bore 111 continues below the internal wedge conforming space 123 as a pair of hemicylindrical surfaces 125 in the upper portion 53 , as well as a pair of hemicylindrical surfaces 127 in the pair of spreading legs 39 and 41 . Referring to FIG. 16 a view of obturator 33 similar to that of FIG. 15 , but turned ninety degrees along its axis is seen. In this view, the wedge 51 is seen as having a narrower dimension to lend internal stability by narrowing the bearing area of the wedge 51 action in opening the pair of spreading legs 39 and 41 . Referring to FIG. 17 , a closeup view of the external hinge assembly 77 seen in FIG. 1 illustrates the optional use of a plug 131 to cover the exposed side of the circular protrusion 81 . Referring to FIG. 18 , a view taken along line 18 — 18 of FIG. 11 illustrates a view which facilitates the showing of an optional skirt, including a skirt section 133 welded or otherwise attached to lower tube hemicylindrical portion 65 , and a skirt section 133 welded or otherwise attached to lower tube hemicylindrical portion 69 . The skirts sections 133 and 135 are made of thin flexible metal and interfit within a pair of accommodation slots 137 and 139 , respectively. Referring to FIG. 19 , a view of the lower tube hemicylindrical portions 65 and 69 in a close relationship illustrates the manner in which the skirts sections 133 and 135 fit within the accommodation slots 137 and 139 when the lower tube hemicylindrical portions 65 and 69 are brought together to a circular configuration. Referring to FIG. 20 , a cross sectional view of the a patient 151 spine 153 is shown for illustration of the general sequence of steps taken for any procedure utilizing the minimal incision maximal access system 31 . There are several procedures utilizable with the minimal incision maximal access system 31 . Only a first procedure will be discussed using illustrative figures. Other procedures will be discussed after minor variations on the minimal incision maximal access system 31 are given below. Procedure I: Diskectomy and Nerve Decompression The patient 151 is placed prone on radiolucent operating table such as a Jackson Table. The patient 151 is then prepared and draped. The operative area is prepared and localized and an imaging device is prepared. A guide pin 155 is insert through the patient's skin 157 , preferably under fluoroscopic guidance. In the alternative and or in combination, the patient 151 skin can be incised with a scalpel. Other features in FIG. 20 include the dural sac 159 , and ruptured intervertebral disc 161 . Referring to FIG. 21 , a fascial incisor 169 overfits the guide pin 155 and is further inserted to cut through external and internal tissue. The fascial incisor 169 is then removed while the guide pin 155 is left in place. Next, using the obturator 33 , the surgeon clears the multifidus attachment with wig-wag motion of the obturator 33 tip end. Next the obturator 33 is actuated to gently spread the multifidus muscle, and then closed. Referring to FIG. 22 , next the assembled Working Tube 35 —Obturator 33 is inserted into the area previously occupied by the fascial incisor 169 and advanced to the operative level lamina and remove the obturator 33 . As an alternative, and upon having difficulty, the obturator 33 could be initially inserted, followed by an overfit of the working tube 35 . In another possibility, a smaller size of obturator 33 and working tube 35 or combination thereof could be initially utilized, followed by larger sizes of the same obturator 33 and working tube 35 . The assembled Working Tube 35 —Obturator 33 in place is shown in FIG. 22 with the working ends very near the spine. Referring to FIG. 23 , the obturator 33 is actuated to a spread orientation, which automatically actuates the working tube 35 to a spread orientation. Spread is had to the desired exposure size. The obturator 33 is thin actuated to a closed or non-spreading position. The obturator and working tube is then again advanced to dock on the spine. The working tube 35 is then fixed to assume an open position either by utilization of the locking pin 87 or other fixation device to cause the working tube 35 to remain open. Then, once the working tube 35 is locked into an open position, the obturator 33 is actuated to a closed or non-spread position and gently removed from the working tube 35 . Referring to FIG. 24 , the working tube 35 is in place. The working tube 35 may be secured by structure ultimately attached to an operating table. The working tube 35 may be held or stabilized in the field of view by a support 181 which may have an engagement sleeve 183 which fits onto the working tube. As can be seen, the operative field adjacent the spine area is expended even though the incision area is limited. The deeper a given size of working tube 35 is inserted, the smaller its entrance area. After the working tube 35 is stabilized, the surgeon will typically clear the remaining multifidus remnant at the working level and then set up and insert an endoscope or use operating microscope or loupes. The surgeon is now ready to proceed with laminotomy. Referring to FIG. 25 , further detail on the support 181 and engagement sleeve 183 is shown. A base support 185 may support a ball joint 187 , which may in turn support the support 181 . The support 181 is shown as supporting a variation on the engagement sleeve 183 as a pivot point support engagement end 188 having arm supports 189 and 191 . The arm supports 189 and 191 engage the external pivot structure on the working tube 35 which was shown, for example, in FIG. 1 to be the external hinge assembly 77 . As a further possibility, the upper angled hemicylindrical portions 67 and 71 are shown as being engaged about their outer periphery by an adjustable clamp 195 . Adjustable clamp 195 includes a band 197 encircling the upper angled hemicylindrical portions 67 and 71 . The ends of band 197 form a pair of opposing plates 199 and are engaged by a nut 201 and bolt 203 assembly. Referring to FIG. 26 , a side view of the assembly seen in FIG. 25 is seen with the adjustable clamp 195 operable to hold the working tube 35 open at any position. Referring to FIG. 27 , a top view looking down upon the adjustable clamp 195 seen in FIGS. 25-27 shows the orientation of the working tube 35 and adjustable clamp 195 in fully closed position. When used in conjunction with the adjustable clamp 195 , the Reinforced wear plates 73 and 93 are eliminated so as to provide a smooth interface against the exterior of the upper angled hemicylindrical portions 67 and 71 . Referring to FIG. 28 , a variation on the obturator 33 is seen. An obturator 215 has handles 217 and 219 which operate about a pivot point 221 . A working tube 222 is somewhat simplified but is equivalent to the working tube 35 and is shown as including upper angled hemicylindrical portions 67 and 71 . Handle 219 has a ratchet member 223 extending from it and a latch 227 pivotally connected about pivot point 229 to handle 217 . Referring to FIG. 29 , a variation on obturator 33 is seen as an obturator 241 having an upper housing 243 , control shaft 245 having a threaded section 247 and operating through a ball nut 249 . A wedge 251 is extendable down through an operation space made up of a half space 253 in a leg 255 and a half space 257 in a leg 259 . Hinge structures 261 are shown attaching the legs 255 and 259 to the upper housing 243 . A through bore 111 is also seen as extending from the knob 261 through to the bottom of the wedge 251 . An access groove 263 is carried by the leg 259 while An access groove 263 is carried by the leg 259 while an access groove 265 is carried by the leg 255 . Referring to FIG. 30 , a sectional view taken along line 30 — 30 of FIG. 29 illustrates the use of a central support block 271 to support the a central threaded surface 273 and the legs 255 and 259 . Referring to FIG. 31 , a view of a thin, inset hinge 281 utilizable with any of the obturators, but particularly obturators 33 and 241 , is shown. In the case of obturator 33 , by way of example, upper portions 53 accommodate control shaft 49 with its through bore 111 . Inset hinge 281 may be implaced with an inset 283 and secured with machine screws 285 . Inset hinge 281 may be made of a “living hinge” material such as a hard plastic, or it can have its operations base upon control bending of a pre-specified length of steel, since the angle of bend is slight. The connection between the upper portions 53 and the upper control housing 37 may be by any sort of interlocking mechanism, the aforementioned pivot blocks 59 or other mechanism. Referring to FIG. 32 , a sectional view of the obturator 33 within the working tube 35 is seen. The wedge 51 is seen at the bottom of the internal wedge conforming space 123 . Once the spreading of the working tube 35 is accomplished the working tube 35 is kept open by any of the methods disclosed herein. Also seen is a pivot ball 116 to allow the control shaft 49 to turn with respect to the wedge. The pivot ball will continue to support a central aperture bore 111 . Once the working tube 35 is stabilized in its open position, the obturator 33 is, returned to its collapsed state as is shown in FIG. 33 . Provision of electro-mechanical power to the operation of the working tube 35 can provide a surgeon an additional degree of instant control. Referring to FIG. 34 , a top and schematic view of the use of a remote power control to provide instant control of the working tube 25 , similar to the view seen in FIG. 25 illustrates the use of a remote annular control cable 301 using an internal cable 303 which is closely attached using a guide 305 and which circles the upper angled hemicylindrical portion 67 and 71 , terminating at an end fitting 307 . The annular cable 301 is controlled by a BATTERY MOTOR BOX 311 having a forward and reverse switch 313 (with off or non actuation being the middle position). This enables the surgeon to expand the surgical field as needed and to collapse the surgical field to focus on certain working areas. BATTERY MOTOR BOX 311 is configured with gears to cause the cable 303 to forcibly move axially within the annular cable 301 to transmit mechanical power to the working tube 35 . Referring to FIG. 35 , a view taken along line 35 — 35 of FIG. 34 illustrates how the cable 303 is held in place and a closeup of the end termination 307 . Referring to FIG. 36 , a mechanically operated version of the nut 201 and bolt 203 constriction band seen in FIG. 25 . The mechanical power linkage can be provided remotely as by a rotating annular cable, but the basic mechanical setup shown illustrates the mechanical principles. On the bolt 203 , a gear head 325 is implaced, either by attachment or by the provision of a threaded member and gear head made together. A second gear head 327 is utilized to show the possibility of providing a right angle power take-off in the event that the power connection interferes with the area around the surgical field. A shaft 329 extends from a BATTERY MOTOR BOX 331 . The BATTERY MOTOR BOX 331 has a forward and reverse switch 333 ,(with off or non actuation being the middle position). Shaft 329 could be flexible and connected directly into axial alignment with the threaded member of bolt 201 or an integrally formed threaded member. Advantages Over Existing Surgical Techniques In terms of general advantages, there are differences between the minimal incision maximal access system 31 , and its components as described in all of the drawings herein (but which will be referred throughout herein simply as the minimal incision maximal access system 31 , or simply system 31 ) and other devices and procedures. 1. With regard to the Traditional microdiskectomy technique, the minimal incision maximal access system 31 allows for at least the same, if not better visualization access of the operative field. System 31 offers the same 3-Dimensional work ability or, if preferred, an endoscope can be utilized. System 31 minimizes muscle injury with spread versus extensive cautery dissection. System 31 has clear advantage on the challenging obese and very large patient where the traditional microdiskectomy technique is almost impossible to be applied. 2. With regard to open pedicle screw insertion procedures, system 31 offers muscle approach minimizing muscle devascularization and denervation. The traditional approach had required at least one level proximal and one level distal additional exposure causing extensive muscle injury often leading to “fibrotic” muscle changes resulting in chronic painful and stiff lower back syndrome. System 31 offers the most direct approach to the pedicle entry point selecting the avascular plane between the longissimus and multifidus muscles. 3. With regard to the Sextant Procedure, system 31 offers clear advantage over the Sextant procedure. First, the system 31 offers a procedure which is not a blind pedicle screw technique. System 31 can be applied to larger and more obese patients in which the Sextant procedure cannot be utilized. In this procedure using system 31 oosterolateral fusion can be performed along with insertion of the pedicle screws. The sextant procedure is strictly a tension band stabilization. In general, the components of the minimal incision maximal access system 31 are very simple the hemispherical shapes used for the working tube can be round or oval. A keying system can be had to align the obturator 33 to the working tube 35 . In the case of an oval system, the alignment would be automatic. The minimal incision maximal access system 31 is a modular system with interchangeable parts for both the working tube 35 and the obturator 33 . The guide Pin 155 is of simple construction, as is the fascial incisor 169 . The working tube 35 has a limited number of basic parts, and can be made in the simple, two main piece version of FIG. 28 , or the multi-piece version of FIG. 1 , which enables retractor-sleeve substitution. A hinge and stabilization mechanism completes the simplified construction. The obturator 33 is also of simple construction, with upper control housing 37 , pair of spreading legs 39 and 41 , and an internal hinge, whether the pivot blocks 59 or hinge 281 and its ability to support a control shaft 49 having a bore 111 for a guide pin 155 . Guide pin 155 may preferably have a size of from about 0.3 mm to 0.40 mm diameter and 30 cm to 40 cm in length. The fascial incisor may preferably be cannulated for usage with the guide pin 155 and have a width of about 2 mm more than the associated retractor. The overall cutting head length of about 1.2 cm has a shape as indicated in the Figures and has a thickness slightly larger than that of the guide pin 155 . The working tube 35 can have several variations and added details including the simplest shapes as dictated by intended usage. Working tube 35 can have a simple fluted hemitube shape or a Slanted box shape. Further, the possibility of a fluted oval shape is dictated when the approach is more angular. The working tube 35 can have an attachment for an endoscope. Working tube 35 can also have a non-symmetric appearance as by having longitudinal cross sectional shape with half of its shape being rounded and one half of its shape being rectangular or box shaped. This could also give rise to a similarly shaped obturator 33 . The working tube 35 should have an anti-reflective inner coating and may be of modular construction. The preferred lower dimensions for the lower tube hemicylindrical portions 65 and 69 include an overall shape which is semi tubular round or oval and having a width of from about 1.6-3.0 cm and a length of from about 4.0-18 cm. Hemicylindrical portions 65 and 69 may have custom cut outs depending upon planned application. The hinge assembly 77 may have male-female post or male-female dial lock design, as well as a hinge housing and a bias (by spring or other mechanism) to keep angular displaceable portions of the working tube 35 closed. A “universal” port provides a point of attachment of an endoscopic or stabilizer bar. The obturator 33 may be any controlled opening device including a circular band or cable, force Plates, or a device attached to hinge assembly 77 or other hinge assembly. All sleeve attachments including the attachable legs 39 and 41 , as well as the lower tube hemicylindrical portions 65 and 69 should be of the friction grip type or snap and lock type or other suitable connection method or structure. Obturator 215 may have squeeze grip scissor style handles 219 and 217 and a controlled dilator. It may utilize an enclosed design with a handle cover having a no-slip surface. It may be attached to the hinge housing of the working tube or separate hinge housing. In fact, it may be of a design to be held in place solely by the working tube 35 . Ideally a cavity will be provided through the center axis to contain the shaft for the dilator mechanism if applicable. The central bore 111 of the obturator 33 may have a diameter of from about 5-10 mm, depending upon the size of the obturator 33 utilized. Obturator 33 should be provided in various widths and length to match working tube. The working tips of the spreading legs 39 and 41 may be changeable according to surgical procedures as described in the operative procedures herein. It may have an inner chamber, or internal wedge conforming space 123 slanted in shape wider proximal and more narrow distal to accommodate the wedge 51 . The internal wedge conforming space 123 can be enclosed with expanding, contracting sleeve. Other Procedures Many other procedures can be facilitated with the use of the inventive minimal incision maximal access system 31 and methods practiced therewith. Procedure I, a diskectomy and nerve decompression procedure was described above with reference to the Figures. Other procedures are as follows: Procedure II: Facet Fusion 1. Patient prone on Jackson Table with normal lordosis preserved. This can be increased by placing additional thigh and chest support to increase lumbar lordosis. 2. Insert percutaneous special guide pin perpendicular to the floor at a point 1 cm caudal to the Alar-Superior facet notch. 3. Apply a flag guide to a first guide pin 155 # 1 . 4. Measure skin to bone depth from the scale on guide pin 155 # 1 . 5. Slide drill guide mechanism on the flag guide to match the skin bone distance. 6. Insert guide pin 155 # 2 through the drill guide to dock on the superior facet. 7. Make a small skin incision for the obturator 33 . 8. Working tube 35 should be small oval or round with medial cutout to maximally medialize the working tube 35 . 9. Advance the working tube 35 to the L 5 -S 1 joint and dock. 10. Drill the guide pin across the joint medial to lateral, rostral to caudal. If in proper position, advance across the joint to engage the ala. 11. Drill across the joint with a cannulated drill. 12. Check depth flouroscopically and measure. 13. Pick appropriate screw length. 14. Insert specially designed facet screw and protective bracket, secure tightly. Procedure III: Posterior Lumbar Interbody Fusion (PLIF) 1. First half of the procedure similar to microdiskectomy (Procedure I) except for the use of a larger diameter sized working tube 35 . Use a 20-25 mm round or elliptical diameter working tube 35 with a medial cutout to allow docking as close to midline as possible. 2. Following diskectomy enlarge the laminotomy to accommodate the tools use for the specific PLIF such as Brantigan cage or Tangent. Procedure IV: Transfacet Interbody Fusion (TFIF) 1. Follow the same procedure as the PLIF in terms of selecting and inserting the Working Tube 35 . 2. Following the diskectomy, resect the facet joint. 3. Approach the posterolateral disc space through the medial ⅔ of the facet joint. Take care not to injure the exiting root above. 4. Proceed with Brantigan cage instruments and interbody cages. Procedure V: Pedicle Screw Instrumentation Technique 1. Place the patient 151 Prone position on a Jackson Table. 2. Guide pin 155 is docked on facet joint angled 30 degree lateral to medial in the plane between the longissimus muscle longitudinally and multifidus muscle medially. 3. Make skin incision. 4. Fascial incisor introduction. 5. Introduce the obturator 33 working tube 35 assembly between the longissimus and multifidus and progressively open the obturator 33 tip ends of the legs 39 and 41 p , gradually reaching from the joint above and the joint below. 6. Advance the working tube 35 and retract the obturator 33 . 7. Use the elliptical Working Tube size 2.5 cm wide and open up to 5 cm. Procedure IV: Anterior Lateral Lumbar Diskectomy Fusion 1. Mid lateral decubitus position left side up. Place a “waist roll” to prevent sag of the mid lumbar spine. 2. Identify proper level of surgery fluoroscopically. 3. Insert a guide pin 155 # 1 percutaneously into the superior facet perpendicular to the spine. 4. Measure depth skin to joint on the scaled guide pin 155 # 1 . 5. Insert cannulated flag guide over guide pin 155 # 1 . 6. Slide the drill guide to match the depth. 7. Insert a guide pin 155 # 2 down to the disc space. 8. Make skin incision and insert fascial cover. 9. Insert the working tube 35 and Obturator 33 combination. 10. Progressively dilate the obturator 33 . 11. Advance the working tube 35 . 12. Perform anterolateral diskectomy and interbody fusion as taught above. 13. Use a round or oval shaped retractor or lower tube hemicylindrical portion 65 and 69 as inserts preferably with distal end cutouts in each. Procedure VII: Posterior Cervical Foramenotomy and Lateral Mass Plating 1. The patient is placed in a prone position on a Jackson table. 2. Fluoroscopic identification of the level of surgery is had. 3. Percutaneously insert guide pin 155 with AP and lateral fluoroscopic views. 4. Make the initial skin incision. 5. Apply the working tube 35 with obturator 33 into the incision. 6. Perform slow dilation of the muscle. 7. Advance the working tube 35 and collapse and remove the obturator 33 . 8. Proceed with surgery. Type of sleeve or lower tube hemicylindrical portion 65 should be round or oval with slanted and to match the slanted lamina. 9. For application for Lateral mass plating use an oval working tube 35 for a greater exposure. Procedure VIII: Anterior Cervical Diskectomy Fusion 1. Begin with standard anterior cervical diskectomy fusion approach with a incision on the left or right side of the neck. 2. Blunt finger dissection is performed between the lateral vascular structures and the medial strap muscle and visceral structures down to the prevertebral fascia. 3. Establish the correct level to be operated on fluoroscopically and the guide pin 155 inserted into the disc. 4. Apply the working tube 35 and obturator 33 combination and dock at the proper level of the anterior sping. 5. Open the working tube 35 and obturator 33 . 6. Mobilize longus colli muscle. 7. Use special Bent Homen Retractor specifically design to retract the longus colli. 8. Proceed with surgery. Procedure IX: Anterior Lumbar Interbody Fusion 1. Begin with the standard approach whether it is retroperitoneal, transperitoneal or laparoscopic. 2. Apply the special anterior lumbar interbody fusion working tube 35 and obturator 33 . This is a design with a medial lateral opening. It is oval shape and preferably with skirts 133 and 135 . The distal end of the retractor sleeve is slightly flared outward to retract the vessels safely. There is a skirt 133 or 135 applied to the cephalad side and possibly to the caudal side. 3. With the vessels and the abdominal contents safely retracted out of harms way, proceed with diskectomy and fusion. While the present system 31 has been described in terms of a system of instruments and procedures for facilitating the performance of a microscopic lumbar diskectomy procedure, one skilled in the art will realize that the structure and techniques of the present system 31 can be applied to many appliances including any appliance which utilizes the embodiments of the instrumentation of the system 31 or any process which utilizes the steps of the system 31 . Although the system 31 has been derived with reference to particular illustrative embodiments thereof, many changes and modifications of the system 31 may become apparent to those skilled in the art without departing from the spirit and scope of the system 31 . Therefore, included within the patent warranted hereon are all such changes and modifications as may reasonably and properly be included within the scope of this contribution to the art.

A minimal incision maximal access system allows for maximum desirable exposure along with maximum access to the operative field utilizing a minimum incision as small as the METRx and Endius systems. Instead of multiple insertions of dilating tubes the design is is a streamlined single entry device to avoid repetitive skin surface entry. The system offers the capability to expand to optimum exposure size for the surgery utilizing hinged bi-hemispherical or oval working tubes applied over an introducer obturator which is controllably dilated to slowly separate muscle tissue. Deeper end working and visualization areas with maximum proximal access and work dimensions are provided to makes the operative procedure safer in application and shorten the surgeons's learning curve because it most closely approximates the ability to use open microdiskectomy techniques.

FIELD OF THE INVENTION [0001] The present invention relates to power tongs of the type commonly used to make up and break apart oilfield tubular threaded connections. More particularly, this invention relates to an improved open throat power tong which may be laterally moved on and off a tubular string, and to an improved door for such a power tong which will extend across the open throat when in the closed position and will expose the open throat when in the opened position. BACKGROUND OF THE INVENTION [0002] Power tongs have been used for decades to make up and break apart oilfield tubular connections. While such power tongs have a variety of configurations, and different mechanisms for both gripping and rotating an upper tubular pipe relative to a lower tubular pipe, such power tongs generally may be classified as being either the closed throat type or the open throat type. Closed throat power tongs provide a tong body which fully encircles the tubular string, so that repeated oilfield threaded connections pass axially through an opening in the closed throat power tong. [0003] The body of an open throat power tong, on the other hand, typically encircles a majority of the oilfield tubular connection, but an open throat is provided in the tong body to allow the tong to be laterally moved on and off the tubular string. Likewise, a majority of a rotary ring may typically encircle a majority of the tubular and may rotate around the tubular, within the tong body. Most open throat power tongs are provided with a door which accordingly is opened to expose the open throat of the power tong when the tong is not being operated. The door assembly of an open throat power tong is typically closed and latched when the power tong is operated to increase the reliable torque output of the power tong by preventing “spreading” of the open throat and/or to safely retain the tubular within the throat while rotating the tubular. The door assembly provides an open throat tong with the ability to fully encompass a tubular member to aid in safely and securely gripping and rotating the tubular. Also, closing the tong door may increase the safety of the power tong by preventing a tong operator from inadvertently engaging the power tong rotating ring prior to correct tong engagement with the pipe, and may prevent jamming of the rotating ring due to misalignment with the door assembly. [0004] Various types of latching mechanisms have been used in the power tong industry to retain the pivotal door in the closed position. The commonly used latching mechanism in an open throat power tong employs a heavy duty hammer latch mechanism which includes a latch arm pivotally connected to one of a pair of doors positioned on opposing sides of the open throat. Alternatively, a single door may extend across the open throat so that the latch arm on the door engages a lug on the tong body. In either case, a latch head at the end of the latch arm engages a latch lug or stop to retain the door or the pair of doors in the closed position. The latch head and the latch lug typically have planar surfaces which engage when the door or the pair of doors are in the closed position. The heavy duty latch mechanism and door are sufficient to withstand a substantial lateral force, and thus minimize spreading of the open throat of the power tong. To open the doors, the operator manually grasps a handle secured to the latch arm and pulls the latch arm away from the latch stop to disengage the mating surfaces. With the door or doors opened, a power tong may then be moved laterally on and off a tubular string. [0005] When the double door open throat power tong is positioned about the tubular string and prior to activating the partial ring, the door with the latch stop is first closed, then the door with the latch arm is manually closed. The latch arm conventionally includes a spring member which biases the latch arm to the closed position relative to its supporting door. By applying a considerable closing force to the door supporting the latch arm, a cam surface on a latch head engages a corresponding cam surface on the latch stop which causes the latch arm to pivot toward an opened position while the latch head moves radially outward from the latch stop. Once the latch arm is pivotally moved to the opened position, the latch head moves radially inward relative to the latch stop so that the planar surfaces on the latch head and the latch stop engage. The spring on the latch arm may serve to provide additional force which retains the doors closed. [0006] A significant disadvantage of the power tong door discussed above is that it typically requires a relatively large amount of closing force to shut the doors while the latch head moves radially outward with respect to the latch stop, so that the latch head will then be properly positioned so that it may move back radially inward relative to the latch stop and secure the doors closed. This large closing force requires that the door components be sized both for withstanding the spreading force discussed above, and also to ensure that components are sufficiently rugged to withstand the repeated substantially jarring force which these components endure during closing of the door. [0007] A related drawback of this prior art system is that a great deal of effort is required by a tong operator to close the door, which unfortunately increases the tendency for the operator to merely position the door in the partially closed position and not fully latch the door closed. Failure to latch the door closed creates a safety risk, as discussed above, and may also result in tong spreading when high torque is used to make up or break apart the threaded connection. [0008] A second generally distinguishing characteristic between tongs, (other than open/closed throat design), is design of the jaw system. Tongs may generally be classified as either the two jaw system or three jaw system. A two jaw tong system typically includes two sets of gripping jaws segments provided within the tong body, with both sets combining to provide a maximum gripping area of 360 degrees less the circumferential door area. A three jaw tong system typically includes a two jaw system plus a third jaw that is located within the tong door segment, thereby ideally affording substantially 360 degrees of jaw gripping surface to a tubular member. [0009] A drawback of prior art three jaw tongs is that gear pins were required to attach the body ring gear section with the door ring gear section. One gear pin was included on the hinge side of the gear door segment and a second pin was provided on the latch side of the ring gear door segment. A second set of pins or a pin and latch mechanism, were used to pivot and latch the door assembly to the tong body. Each time the door segment were opened or closed, the latch side of the door were unlatched and/or unpinned, as appropriate. In addition, at least one side of the ring gear door segment was also unpinned. Such operations were and are time consuming, and increase the complexity and reliability of the tongs. Additional problems include maintaining proper alignment of gear, door, pin, latch and housing components each time the tong door is closed. Pins typically require a tight fit and alignment between components can be critical to proper rotation of the gear and/or to proper tong operation. If improperly aligned or if the door is improperly closed or latched, the tong gear may seize and lock up the rotational tong components. Operation of a power tong with the door opened may be dangerous and is not recommended except under special circumstances and with appropriate safety precautions. If the tong is operated with the door opened, the rotational components may jam and require some tong disassembly to disengage the jammed components. Also, if operated with the door opened, there is a possibility of the ring segment coming partially or completely out of the tong. [0010] A prior art power tong is incorporated herein by reference, which was filed Jan. 13, 1999, as file number Eckel-71. Eckel-71 discloses a latch mechanism that may require a relatively lower force and effort to open and close the door and latch mechanism. [0011] The disadvantages of the prior art are overcome by the present invention. An improved open throat power tong is disclosed including a door that provides a non-pinned, rotating gear section and a rotating third gripping jaw, within the door section for the power tong. The door of the present invention may significantly increase the area over which the tong grips the tubular, such that an increased make up and/or break out torque may be applied without increasing risk of collapsing or damaging the tubular. SUMMARY OF THE INVENTION [0012] An improved open throat power tong for making up and/or breaking apart an oilfield tubular connection includes a tong body having an open throat therein, and a partial ring member having an open throat. The partial ring member having an open throat may be rotatably supported on the tong body for rotating one tubular member relative to another during a connection make up and/or break out operation. At least two heads may be included on the partial ring member that are rotatable with the partial ring for gripping engagement with the upper oilfield tubular. A door is included which may be pivotally connected to the tong body adjacent a side of the open throat, wherein the door extends at least partially across the open throat when in the closed position, and when in the opened position exposes the open throat to enable the power tong to be moved laterally on and off the oilfield tubular. A ring segment is included which may be rotatably supported within the door for rotating in conjunction with the partial ring member. The ring segment may carry one or more heads for gripping engagement with the upper tubular. A hydraulic drive motor may be provided for powering rotation of the partial ring member, the ring segment and the first tubular. [0013] A rotational support mechanism, such as rollers and/or bearings, may be provided in the tong body to define the rotational path for the partial ring member and the ring segment. The support mechanism may also prevent spreading of the open throat in the partial ring member under high torque operations by confining radial movement or other deflection of the partial ring member or the ring segment. [0014] A latch mechanism may be provided to secure the door to the tong body when the door is in the closed position. The latch mechanism may be at least partially secured to the door. A latch arm is pivotally moveable between a latch arm closed position and a latch arm opened position. The latch mechanism may include a latch coupling and a pivotally mounted inner latch head, both for engaging a latch stop. The latch stop may be fixedly secured to the tong body, adjacent a side of the open throat. When the door and latch mechanism and are in the closed and latched positions respectively, the inner latch head and the latch coupling may engage the latch stop and the outer latch head may engage the inner latch head to lock the inner latch head in engagement with the latch stop. [0015] The improved open throat power tong provides for a simplified, reliable rotating mechanism in that the partial ring member and the ring segment are structurally independent from one another, both during door opening/closing, and while rotating the partial ring member and ring segment in unison to make up and/or break out a tubular connection. When the door is closed, the ring segment may substantially fill in the open throat portion of the partial ring member, essentially providing up to 360 degrees of gripping area around the tubular member. The partial ring member and ring segment substantially rotate along a common plane, at a common radius about a common axis. [0016] During rotation, a planar or configured end surface of the ring segment may engage a similar end surface configuration of the partial ring member, however, the ring segment and partial ring member may remain structurally independent from each other. To open the door of the power tong, rotation may be interrupted when the ring segment is substantially aligned with the door in the open throat of the tong body. The door may then be opened and in so doing the ring segment may pivot out of the open throat with the door. When the door is opened or unlatched, a retainer arm may engage the ring segment to secure the ring segment within the door and to prevent the ring segment from coming out of the door while the door is opened, until the door is closed and the latch is latched, wherein the retainer arm may disengage from the ring segment. As the ring segment may be structurally independent of the partial ring member during rotation, when the door is closed the ring segment may be immediately ready for rotational operation as no pins are required to connect or align the ring segment with the partial ring member. [0017] The present invention provides a power tong with an improved three or more jaw gripping mechanism to facilitate applying higher torque to make up and break out operations by distributing the rotational torque over a larger circumference on the tubular member than a two jaw gripping system. Such enhanced force distribution may reduce the risk of crushing the tubular while also facilitating the application of additional torque. [0018] It is an object of the present invention to provide a high torque power tong that may incorporate at least three gripping jaws with the tong having a reduced propensity for jamming or binding of the partial ring member and/or the ring segment, during rotation. The unsecured or “floating” ring segment of the preferred embodiment is not secured to the partial ring member. A rotational guide mechanism is provided which facilitates unison rotation of both the ring segment and the partial ring member about a substantially common plane and axis, in a torque range from low to high, without requiring critical alignment between the door, tong body, partial ring member and ring segment. [0019] It is also an object of the present invention to provide an open throat power tong with an improved door which will reliably latch the door in the closed position, and which may close with a relatively low closing force. A latch assembly is disclosed which closes reliably with relatively low closing force while also self latching in conjunction with the door closing, such that door latching is accomplished in the same operation as door closing. The preferred embodiment latch assembly increases the likelihood that the tong operator will reliably latch the door of an open throat power tong in the closed position before operating the power tong. The latching system disclosed herein is reliably self latching upon closing of the door. Alternatively, other latching mechanisms may be utilized with the ring segment and partial ring member combination. [0020] It is a feature of the present invention that the latching mechanism securely latches the door to the tong body when the door is in the closed position, and in addition may strengthen the power tong by preventing spreading of the open throat under high torque. The latch mechanism may support load and tong deformation forces in a plurality of orientations. [0021] It is a significant feature of the present invention that the power tong may save time and effort in opening and closing the door as the ring segment and partial ring member do not require pinning or otherwise connecting with each other. The ring segment is structurally independent from the partial ring member. The partial ring member and ring segment may be rotated in unison within the tong and door to make up or break out a connection from substantially the time the door is closed. In addition, the door may be opened substantially immediately after ceasing rotation and aligning the ring segment with the door. [0022] It is a feature of this invention that the partial ring member may be rotated while the door is opened and the ring segment non-rotationally contained within the door. Although it is recommended that the door be closed during normal operation of the power tong, the tong door does not have to be closed for the tong to operate, and the ring segment does not have to be engaged with the partial ring member for the tong to operate. The circumferential distance between two driving idler gears in the tong body that engage the partial ring member to rotate the partial ring member is thus greater than the circumferential gap in the partial ring member. During rotation of the partial ring member while in the absence of the ring segment, e.g., when the door is opened and the ring segment is not rotating, at least one idler gear may at all times engage and drive the partial ring member. Thereby, if necessary and under special safety measures, the tong may be briefly operated with the door opened. [0023] It is not recommended that the tong be normally operated with the door opened. The tong should only be operated with the door closed. Should special circumstances arise when may be necessary briefly to operate the tong with the door opened, extreme care, caution and special safety measures should be exercised to avoid injury. [0024] It is also a feature of the present invention that the rotational partial ring member and ring segment may not be as susceptible to binding and jamming as may occur when ring segments and partial ring members are structurally pinned or otherwise interconnected. [0025] Another feature of the invention is that the door for the power tong may include a single door which extends across the open throat of a power tong, or may include a pair of doors each pivotally connected to the tong body at opposing sides of the open throat of the power tong, with one of the doors supporting a latch stop thereon. In such embodiment, one of the doors may also support a head for gripping the tubular. [0026] An advantage of the present invention is that the fatigue on the operator is reduced by significantly reducing the effort required to both close the door and concurrently latch the door in the closed position in a single operation. [0027] Yet another advantage of the invention is that the door and the floating ring segment mechanism are reliable, simple and may be inexpensively manufactured. Binding, jamming and alignment problems may be reduced by allowing the ring segment to “flex,” “float,” move vertically or otherwise, relative to the partial ring member. [0028] These and further objects, features, and advantages of the present invention will become apparent from the following detailed description, wherein reference is made to figures in the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS [0029] [0029]FIG. 1 is a top view illustration of a power tong embodiment with the latch mechanism unlatched and the door opened, with the top cover partially removed. [0030] [0030]FIG. 2 is a top view illustration of the power tong illustrated in FIG. 1, with the door closed and latched. [0031] [0031]FIG. 3 is a bottom view of a section of the power tong with the door opened and the latch mechanism unlatched. [0032] [0032]FIG. 4 is a cross section view of section 4 - 4 in FIG. 3. [0033] [0033]FIG. 5 is a bottom view of the section of the door and latch illustrated in FIG. 3, with the door closed and the latch mechanism latched. [0034] [0034]FIG. 6 is a three dimensional isometric view of a power tong, generally. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0035] FIGS. 1 - 6 illustrate a generalized, suitable embodiment for an open throat high torque power tong 10 according to the present invention. A power tong door assembly 40 may be pivotally connected to a power tong body 20 by door hinge pin 44 . The door assembly 40 may be opened, as illustrated in FIG. 1, exposing an open throat 25 in the power tong body 20 . The power tong body 20 may include a substantial generally circular opening or central bore 27 near the back of the throat 25 , the circular opening having a central axis 15 . A lower end of a first tubular member 11 , such as an oil field tubular pipe which may be suspended near a second end from a rig derrick (not shown), may be laterally positioned through the open throat 25 and within the central bore 27 . Thereafter, the door 40 may be pivoted closed with the tong body 20 and latched by a latch mechanism 100 , thereby closing the open throat 25 . In such configuration, a central axis of the first tubular member 11 may be generally coaxial with the tong central axis 15 . [0036] Power may be applied to the power tong 10 to cause the power tong 10 to rotate the first tubular member 11 to make up or break out a threaded connection between first tubular member 11 and a second tubular member (not shown). The second tubular member may be typically suspended within a well bore (not shown), below the first tubular member 11 . The power tong door 40 may thereafter be opened to allow the power tong 10 to be laterally removed from engagement with the first tubular member 11 . [0037] High Torque Power Tong [0038] For a preferred embodiment as shown in FIGS. 1 - 6 , the power tong assembly 10 may be powered, hydraulically or otherwise, to impart torque upon and rotate the first tubular member 11 . A gear assembly 22 may be included in the transition of power through the tong 10 . Additional tong components may include a partial ring member 30 and a plurality of jaw members engaged thereto, for gripping the first tubular member 11 . The tong body 20 may provide an open throat for laterally moving the tong between engagement and disengagement with the tubular member 11 . A generally circular central bore 27 near the back of the open throat 25 may be included to position the tubular member during rotation of the tubular member 11 . The diameter of the circular opening 27 is large enough to accommodate the largest diameter tubular member 11 for which the particular power tong 10 is designed to rotate, plus some additional diameter to facilitate telescopic transmission of such tubular members 11 through the central bore 27 without binding the tubular 11 with the tong 10 . [0039] The tong body 20 may include an upper cage plate 17 which may substantially provide an upper cover on the tong body 20 , and a lower cage plate (not shown) which may substantially provide a lower cover on the tong body 20 , opposing the upper cage plate 17 . A tong frame 19 may generally encompass portions of the periphery of the tong body 20 , excepting for the open throat 25 and the central bore 27 portions of the tong body 20 . The tong frame 19 may enclose at least a portion of an interior of the tong body 20 between and at least partially supporting the upper 17 and lower tong plates. The tong frame 19 may also extend through portions of the interior of the tong body 20 . [0040] The partial ring member 30 is designed to rotate within the tong body 20 , about the central axis 15 . The partial ring member 30 may include a row of gear teeth 58 on a portion of an outer periphery of the partial ring member 30 to rotationally connect the partial ring member 30 with the gear assembly 22 . One or more roller guide surfaces 57 may also be provided on the partial ring member 30 , preferably near an outer periphery of the partial ring member 30 , to engage a plurality of tong body roller guides 52 . The plurality of tong body roller guides 52 may confine rotation of the partial ring member 30 within a rotational course that may be at least partially defined by and supported by the roller guides 52 . In addition, the roller guides 52 may aid in preventing spreading of the partial ring member 30 under applications of high torque by providing lateral support to the partial ring member 30 . [0041] An inner surface of the partial ring member 30 may support at least two heads 36 for selectively gripping the tubular member 11 . The heads 36 may partially move or pivot radially inward toward the central axis 15 during rotation of the partial ring member 30 , such that tong dies (not shown) or other tubular gripping components supported on the heads 36 may engage and grip the tubular 11 . The heads 36 may also be selectively retractable such that the heads 36 may move radially outward toward the partial ring member to release the tubular 11 . [0042] The tong body 20 may support the tong door 40 . The door 40 may be pivotally connected to the tong body 20 adjacent a side of the open throat 25 to extend at least partially across the open throat when the door 40 is in a closed position. When the door 40 is in an opened position the opened throat 25 is exposed, thereby enabling the power tong 10 to be moved laterally on and off tubular 11 . In the closed position, the hinged end of the door 40 may be secured to the tong body 20 by hinge pin 44 , while a latch end of the door 40 is secured to the tong body 20 with a latch mechanism 100 which is latched to a latch stop 114 that is secured to the tong body 20 . [0043] The door assembly 40 generally may securely close the open throat 25 and guide the partial ring member 30 and a ring segment 150 , during rotation. When the door 40 is in the opened position, the door 40 may support the ring segment 150 . The ring segment 150 may support at least one additional jaw member 160 for gripping the tubular 11 . When the door 40 is closed, the ring segment 150 and partial ring member 30 may rotate at least partially within each of the tong body 20 and the door 40 . [0044] The door assembly 40 may include an upper frame portion 154 , a lower portion 164 substantially opposing the upper frame portion 154 , and an outer wall 163 , generally forming a door interior. A door cage plate 148 may also be included to cover a portion of the interior of the door assembly 40 . [0045] The ring segment 150 may be designed to rotate about the central axis 15 along a defined rotational course within each of the tong body 20 and closed door assembly 40 . A radially outward surface of the ring segment 150 may include a row of gear teeth 168 to connect the ring segment 150 with the gear assembly 22 . One or more roller guide surfaces 157 may also be provided on the ring segment 150 , preferably on an outer periphery of the ring segment 150 , to engage a plurality of door roller guides 152 . The plurality of door roller guides 152 may confine and support rotation of the ring segment 150 and partial ring member 30 within the door assembly 40 and tong body 20 along a rotational course at least partially defined by and supported by roller guides 52 and 152 . In addition, the roller guides 152 may aid in preventing spreading of the partial ring member 30 under applications of high torque by providing lateral support to the partial ring member 30 . [0046] An inner surface of the ring segment 150 may support at least one head 160 for selectively gripping the tubular 11 . The head 160 may partially move or pivot radially inward toward the central axis 15 during rotation of the ring segment 150 and partial ring member 30 , such that tong dies (not shown) or other tubular gripping components supported on the heads 36 may engage and grip the tubular 11 . The head 160 may also be selectively retractable such that the head 160 may move radially outward toward the ring segment 150 to release the tubular 11 . [0047] The ring segment 150 may have a radius of curvature and a general configuration that is substantially the same as the partial ring member 30 , with a significant difference being that the arc length of the ring segment 150 may be less than the arc length of the partial ring member 30 . The ring segment 150 may have an arc length that extends across a portion of the open throat 25 wherein the partial ring member 30 may rotate. Consequently, when the door 40 is closed, the ring segment 150 and the partial ring member 30 may substantially encircle the tubular 11 with a 360 degree arc length. [0048] The open throat portion of the partial ring member 30 may include end surfaces 91 and 92 . The ring segment 150 may include ring segment end surfaces 81 and 82 . When the door 40 is closed, ring segment end surfaces 81 and 82 may substantially abut end surfaces 91 and 92 respectively. The ring segment 150 may also include ring segment end surfaces 83 , 84 , 85 and 86 . The partial ring member 30 may include end surfaces 93 , 94 , 95 and 96 . End surfaces 81 and 82 may be staggered from respective adjacent end surfaces 83 and 85 , and 84 and 86 , respectively. Likewise, end surfaces 91 and 92 may be staggered from respective adjacent end surfaces 93 and 95 , and 94 and 96 . A staggering arrangement of end surfaces, such as shown in FIGS. 1 and 2 or otherwise, may provide for interlocking the ring segment 150 and the partial ring member 30 , without structurally connecting the two components, such as with pins. Each end of the partial ring member 30 may be substantially coplanar with a respective mating end of the ring segment 30 . Consequently, as the ring segment 150 and partial ring member 30 rotate, the points of contact between end surfaces of the two components may provide for relative planar displacement and/or for “flexing” between the two components, at the interconnection points. Therefore, binding, jamming and misalignment problems may be reduced while providing a means for at least partial engagement between the two components. [0049] The arc length of the door section 25 of the power tong 10 is relatively small as compared to the outer circumferential arc length of the partial ring member 30 , such that with appropriate safety measures in place the tong 10 may be operated with the door 40 opened. A preferred embodiment of the power tong 10 includes at least two driving idler gears 23 , 24 . The driving idler gears 23 , 24 each may impart rotation to either or both of the partial ring member 30 and the ring segment 150 . The span or arc distance between two driving idler gears 23 , 24 which engage the partial ring member 30 to rotate the partial ring member 30 is greater than the arc length of the gap or open throat 25 in the outer circumferential arc of the partial ring member 30 . Consequently, during rotation of the partial ring member 30 while in absence of the ring segment 150 in common rotation therewith, e.g., when the door 40 is opened and the ring segment 150 is not rotating, at least one driving idler gear 23 , 24 may at all times engage and drive the partial ring member 30 . Thereby, under special circumstances and for brief periods, and with extra safety measures in place, the tong 10 may be briefly operated with the door 40 opened. [0050] In alternative embodiments, end surfaces 91 , 93 and 95 of the partial ring member 30 may be coplanar or angular with respect to respective end surfaces 92 , 94 and 96 of the partial ring member 30 . Likewise, end surfaces 81 , 83 and 85 of the ring segment 30 may be coplanar or angular with respect to respective end surfaces 82 , 84 and 86 . Those skilled in the art will appreciate that many variations may be conceived for relational door, body and ring structure and/or design. [0051] Latch Mechanism [0052] The power tong may 10 may include a latch mechanism 100 partially secured to the door assembly 40 to securely retain the door 40 in the closed position. The disclosed latch mechanism 100 may be simple, reliable and easily latched and unlatched. The latch mechanism 100 may include two portions, namely, a door portion and a tong body portion. [0053] The tong body end of the latch mechanism 100 may include a latch stop 114 which is securely affixed to the tong body 20 , substantially adjacent a side of the open throat. The latch stop 114 may preferably be a single component. The door 40 portion of the latch mechanism 100 may include a door hinge bracket 42 that is secured to the door 40 and which allows the door 40 to pivot on door hinge pin 44 . A latch coupling 122 may be secured to the opposing end of the door 40 to releasably engage the latch stop 114 when the door 40 is in the closed position. The latch coupling 122 may be pivotal secured to the door 40 by pin 124 . The latch coupling 122 may assist in preventing spreading of the open throat 25 during applications of high torque. [0054] A latch arm 132 may be included for latching and releasing the latch mechanism 100 . The latch arm 132 may be pivotally attached to latch arm hinge member 135 , by latch arm hinge pin 134 . A biasing device (not shown), such as a torsion spring, may be included to bias the latch mechanism, including latch arm 132 , in a closing position. Such biasing may assist and secure latching of the latch mechanism. The hinge member 135 may be immovably connected to the door body 154 . The latch arm 132 may be pivotally movable between a latch arm closed position and a latch arm opened position. The latch arm 132 may include an outer latch head 130 having an inner latch head engagement surface 136 for engagement with an offset portion 128 of an inner latch head 120 to latch the door 40 when the door 40 and latch mechanism 100 are in the closed position. A latch handle 146 may be immovably secured to the outer latch head 130 to facilitate opening the latch mechanism 100 . [0055] Inner latch head 120 may be included, which is pivotally connected to the door 40 . The inner latch head 120 may include a latch stop recess 125 for receiving the latch stop 114 . The inner latch head 120 may include an outer latch head engagement surface 126 for engagement with the inner latch head engagement surface 136 on the outer latch head 130 when the latch mechanism 100 is in the latched position. [0056] Prior to opening the door, the ring segment 150 may be rotated to where the ring segment 150 is substantially within the door 40 . The latch mechanism 100 may be released and the door 40 opened by pivoting the door 40 out of the open throat 25 . When the door 40 is in the opened position, the “floating” ring segment may be retained within the door 40 by a retainer arm 141 which may operate in conjunction with the latch mechanism 100 . [0057] Manipulation of the retainer arm 141 in conjunction with the latch mechanism may require additional components, including a retainer connector bracket 138 , which may be secured to the latch arm 132 . The retainer connector bracket 138 may pivot with the latch arm 132 between the latch arm opened position and the latch arm closed position. One or more retainer hinge pins 174 , or other linkage mechanism, may pivotally connect the retainer connector bracket 138 and a retainer arm 141 . A retainer guide 142 may be secured to the door 40 and may provide a channel to telescopically guide movement of the retainer arm 141 . A retainer arm engagement port 151 may be provided in the ring segment 150 for selectively receiving the retainer arm 141 . [0058] Power Tong Operation [0059] A high torque power tong 10 as disclosed in the preferred embodiment may preferably be hydraulically powered, including a hydraulic power source and hydraulic control system (not shown). In the door opened, open throat configuration the power tong may be laterally moved into engagement with a tubular 11 . The tubular 11 may be transmitted through the open throat 25 and into the central bore 27 near the back of the open throat 25 . The door 40 may be pivoted closed such that the ring segment 150 is circumferentially positioned adjacent an open throat 25 portion of the partial ring member 30 . A recessed opening 123 in the latch coupling 122 may engage the latch stop 114 , while a recessed opening 125 in the inner latch head 120 may engage the latch stop 114 . [0060] To secure engagement of the inner latch head 120 and the latch coupling 122 with the latch stop 114 , the latch arm 132 and outer latch head 130 may be pivoted from the opened position to the closed position. The outer latch head 130 may be pivoted into engagement with the offset portion 128 of the inner latch head 120 , such that the inner latch head engagement surface 136 on the outer latch head 130 may engage the outer latch head engagement surface 126 on the inner latch head 120 . [0061] As the latch arm 132 is pivoted to the closed position, the retainer connector bracket 138 which may be affixed to the latch arm 132 , may concurrently pivot with the latch arm 132 , wherein the retainer arm 141 may be telescopically disengaged from the recess 151 in the ring segment 150 . The retainer pin 174 may connect the retainer arm 141 and connector bracket 138 , and the retainer guide 142 may control movement of the retainer arm 141 . [0062] Hydraulic power may be applied to the power tong 10 to cause the engaged tubular member 11 to rotate relative to a second tubular (not shown), in a selected direction to make up or break out a threaded connection between the first tubular II and the second tubular. The power tong 10 may also be operated to rotate more than merely one joint of tubular member 11 ; for example, rotating a full string of connected tubulars such as when drilling, or manipulating downhole tools. Power may be transmitter through the gear assembly 22 preferably to one or more points near the radially outer periphery of the partial ring member 30 and the ring segment 150 , as the partial ring member 30 and ring segment 150 are rotated within the tong body 20 and door 40 . Rotational movement of the partial ring member 30 and ring segment 150 may cause the plurality of jaw members 36 , 38 , 160 to partially move radially inward to engage and grip the tubular member 11 , such that the tubular 11 is rotated in conjunction with the partial ring member 30 and ring segment 150 . Torque may be relaxed or rotation reversed, causing the jaws 36 , 38 , and 160 to disengage from the tubular 11 and retract radially outward away from the tubular 11 . The tubular may then be moved telescopically up or down through the central bore 25 . Subsequent connections may be thereafter selectively made up, broken out and/or otherwise rotated. [0063] To laterally remove the power tong 10 out of engagement from a tubular 11 that is positioned with the central bore 27 , the partial ring member 30 and ring segment 150 may be rotated until the ring segment 150 is substantially positioned within the door 40 and the retainer arm engagement port 151 is aligned with the retainer arm 141 . The latch mechanism 100 may be unlatched, the door 40 opened and the tong 10 moved laterally out of engagement with the tubular II. To unlatch the latch mechanism 100 , an operator may pull laterally outward on the handle 146 , away from the door 40 , causing the outer latch head 130 to disengage from projection 128 on the inner latch head 120 . Concurrently, the retainer connector bracket 138 may cause the retainer arm 141 to partially telescopically penetrate into the retainer arm engagement port 151 to secure the ring segment 150 within the door 40 while the door 40 is in the opened position. [0064] The door 40 may thereafter be pivoted from the closed position within the tong throat 25 to an opened position, thereby exposing the open throat 25 . The power tong 25 may be laterally removed from engagement with the tubular 11 . Because the partial ring member 30 is not secured to the ring segment 150 , in lieu of or prior to removal of the power tong from engagement with the tubular 11 the partial ring member 30 and tubular 11 may be rotated with the door 40 opened and the ring segment removed. In such instance, the partial ring member 30 may traverse the open throat within the rotational course, without the presence or assistance of the door 40 . Normal tong operation with the door opened is not recommended. Injury may result from tong 10 operations with the door 40 opened, due to exposure of moving components within the tong 10 . [0065] In an alternative embodiment of an open throat power tong assembly 10 which provides for a floating ring segment 150 in the door 40 , the inner latch head 120 may be pivotally mounted on the latch coupling 122 . Also, in alternative embodiments, the retainer arm mechanism 138 , 141 , 142 , 151 , and 174 may be of a mechanical configuration other than as disclosed above, such as a friction mechanism, a variation on the disclosed pin configuration, magnets, or a clamp mechanism. Some power tong 10 embodiments may completely eliminate the retainer mechanism and retain the ring segment 150 within the door 40 by close tolerance component fit, or otherwise. [0066] It may be appreciated that various changes to the details of the illustrated embodiments and systems disclosed herein may be made without departing from the spirit of the invention. While preferred embodiments of the present invention have been described and illustrated in detail, it is apparent that still further modifications and adaptations of the preferred and alternative embodiments will occur to those skilled in the art. However, it is to be expressly understood that such modifications and adaptations are within the spirit and scope of the present invention, which is set forth in the following claims.

An open throat power tong 10 as commonly used for making up and/or breaking apart an oilfield tubular connection, comprising a tong body 20, a tong door assembly 40, a partial ring member 30 and a ring segment 150. The partial ring member 30 and ring segment 150 may not be structurally connected and each may support one or more jaw members thereon for gripping a tubular 11. The partial ring member 30 and ring segment 150 may rotate substantially in unison along a substantially common plane and about a common axis, along a defined rotation course through the tong body 20 and door 40. The ring segment 150 may be substantially secured within the door when the door 40 is opened. An improved latch mechanism 100 is included for securing the door 40 to the tong body 20 to facilitate relatively easy closing and latching and unlatching of the door 40 with the tong body 20, and to prevent expansion of the open throat 25 during application of high torque.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention is directed to air control systems for an internal combustion engine and in particular the invention is directed to a start air control system controlling the air flow to the engine to facilitate consistent clean starts having reduced emission of noxious exhaust gases. 2. Prior Art Fundamental to starting an internal combustion engine at either high or low ambient temperatures down to minus 30°F is the provision of an ample air-fuel flow during the cranking of the engine and for a short period of time after the initial start to allow the engine to come up to a self-sustaining running speed in the shortest possible time. The air-fuel flow required during this initial phase of the start cycle for quick clean starts is substantially greater than that provided by the fast idle control normally associated with internal combustion engines. The fast idle control only functions to control the curb idle speed of the engine once it has been started and reaches a self-sustaining speed. In order to consistently achieve successful clean starts particularly at low temperatures, a sufficient air-fuel mixture must be supplied during the cranking period to permit the engine to accelerate from the cranking speed to an initial self-sustaining speed in the shortest possible time. Secondly, the engine should be operated at a substantially higher speed than the fast idle speed to purge the intake manifold of the residual starting fuel condensed in the cold intake manifold during cranking, a limit for the substantially higher start speed in the transition between start and idle, and a relatively smooth transition from the substantially higher start speed to the idle speed after the system has been purged to prevent stalling. The limit on the initial start speed during the transition from start to idle is a safety precaution to minimize damage normally attendant high speed operation of a cold engine when the lubricant is relatively viscous and the distribution incomplete. The prior cold start air for internal combustion engines has been primarily directed to provide the required rich air-fuel mixture during the cranking, initial start, and fast idle warm-up cycle, and has left the requirement for providing the required air-fuel quantity to the operator. Operator manuals for automative vehicles normally contain cold start instructions which include in addition to the proceedure for setting the automatic choke and fast idle accessories, a statement to the effect that the accelerator pedal should be depressed about half-way down and held there until the engine has been successfully started. This proceedure is intended to provide the required quantity of rich air-fuel mixture necessary to start the engine and permit the engine to reach a self-sustaining speed. Admittedly, this proceedure works but is froth with variables which vary from operator to operator as well as from engine to engine. Therefore, successful starting of a cold engine is dependent upon the skill of the operator and can in many instances be damaging to the engine. The invention is directed to a start air system for internal combustion engines which controls the quantity of air during the cranking and initial start phase of a cold engine, thereby removing the operator variables and substantially increasing the consistency and cleanliness of a successful start. Further because the speed of the engine is controlled between the initial start and idle, the engine is always properly purged of residual starting fuel and excessive wear and damage to the engine due to high speed operation under cold conditions minimized. The consistency and cleanliness of the start provided by the disclosed invention is particularly important in view of the existing and future emission standards being imposed on automotive and commercial vehicles, and especially for future vehicles equipped with thermal reactors. SUMMARY OF THE INVENTION The invention is a start air system controlling the quantity of air being supplied to an internal combustion engine during the cranking and initial high speed operation subsequent to a successful start. The system is in addition to the cold start fuel enrichment and fast idle accessories normally associated with internal combustion engines and provides an ample air supply sufficient to successfully start a hot or cold engine. After the engine has been started, the system allows the engine to accelerate to a speed determined by the temperature of the engine. Then after the engine has reached the temperature dependent speed and the engine's air intake manifold purged of residual starting fuel the start air system reduces the air flow to that determined by the engine's conventional idle control at a predetermined rate to prevent stalling of the engine by a too rapid deceleration. The basic system comprises a start air actuator activated by the ignition switch for providing a predetermined air flow to the engine. The actuator may partially open the throttle of the engine's primary operator-actuated air delivery system, open secondary throttles, or provide the required air flow through an auxiliary air flow passage or duct bypassing the throttle in the primary delivery system, a temperature controlled reference speed signal generator generating a signal indicative of the initial speed the engine should reach after starting in order to completely purge the air in fuel delivery systems and be self-sustaining, a comparator comparing the reference speed signal with a signal indicative of the engine's actual speed for deactivating the start air actuator when the actual engine speed equals or exceeds the reference speed signal and a deceleration means for reducing the starting air flow to the engine from its initial flow to that determined by the fast idle control at a predetermined rate. The objective of the invention is an automatic start air system providing consistent, high quality starting of an internal combustion engine. Another objective of the invention is a start air system substantially reducing the emission of noxious exhaust gases during engine starting and compatible with thermal reactors to be used on future vehicles. A further object of the invention is a system for providing a controlled increased cold start air flow to the engine during the cranking and initial starting of the engine to facilitate the starting and acceleration of the engine to a predetermined speed. Another objective of the invention is a control mechanism providing an increased air flow to the engine during the cranking and initial acceleration to a predetermined speed which is a function of the engine's temperature. Another objective of the invention is a start air system which in addition to facilitating the cold start and the acceleration of the engine to the temperature dependent speed automatically reduces the air flow to the engine in a predetermined manner to an air flow indicative of the engine's fast idle air flow rate to prevent stalling. A final objective of the invention is a cold start system adaptable to both carburetor and electronic fuel injection equipped internal combustion engines. The advantages of the system are (1) improved start reliability independent of operator skill; (2) reduction of noxious exhaust emissions; (3) a controlled maximum speed after start to purge the residual starting fuel and protect the engine from accelerating to excessive speeds after starting; and (4) a controlled return to idle speed after starting preventing stalling of the engine after having once been started. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a graph showing the engine speed as a function of time for a typical low temperature start attempt; FIG. 2 is a block diagram showing the basic elements of the start air system; FIG. 3 is an illustration of the start air control system with a solenoid actuating the throttle in the primary air delivery system; FIG. 4 is an alternate embodiment of the system shown in FIG. 3; FIG. 5 is an illustration of the system shown in FIG. 3 with the start air control system deactivated; FIG. 6 is an alternate embodiment of the start air control system having a vacuum motor initially controlling the start air flow; FIG. 7 is an alternate embodiment of the system shown in FIG. 6; FIG. 8 is an illustration showing the solenoid valve controlling the operation of the vacuum motor; and FIG. 9 is a circuit diagram showing a solid-state switch controlling the actuation of the solenoid. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The starting cycle of a typical internal combustion engine starting at -21°F is basically illustrated in FIG. 1 which shows the engine speed as a function of time. The engine starter is engaged at time 0 and after a short period of time, point A on the curve, the engine starts to rotate at a speed predetermined by the speed of the starter drive only. After a few revolutions of the engine indicated as point B, sufficient air and fuel air reach the cylinders and the power generated by the internal combustion adds to the power provided by the starter and the speed of the engine starts to increase rapidly. Shortly thereafter indicated by point C, the speed of the engine has increased to a value sufficient to sustain the operation of the engine at that temperature and the cranking by the starter may be terminated. However, if the air-fuel flow at this point were cut back to the flow determined by the fast idle control, residual fuel initially condensed in the intake manifold during the cranking interval from A to C would revaporize producing an excessively rich fuel-air mixture which may cause the engine to miss and perhaps even stall. In either case the excessive fuel contaminates or fouls the spark plugs resulting in a "dirty" start and the emission of noxious exhaust gases. To purge the engine of the residual fuel, the engine should be allowed to accelerate to a speed significantly higher than the desired idle speed by a continued high volume of air and fuel. Since the residual fuel in the intake manifold is a relatively fixed quantity dependent upon the initial temperature of the engine and other engine parameters the dissipation of the residual fuel in a large quantity of air will have a lesser enrichment effect than dissipating the same amount of residual fuel in a smaller quantity of air. Further, the engine operating at the higher speed is less susceptible to missing and the probability of stalling during the purging process greatly reduced. Both of these factors tend to reduce the emission of noxious exhaust gas and reduce the saturation and contamination of thermal reactors. After the majority of the residual fuel is purged from the intake manifold, indicated by point D, the engine can be returned to its normal idle speed indicated by point F. It is to be noted the purge interval from C to D is dependent upon the quantity of residual fuel condensed in the intake manifold which is in an inverse function of the manifold temperature. Therefore, the quantity of air required to purge the intake manifold increases at lower temperatures. The engine for practical purposes may be considered as a constant volume pump, therefore, the quantity of air flow is dependent on the average pumping speed of the engine times the time. Since the engine is accelerating during the purging period, the time required to purge the engine may also be computed as a function of the engine speed. It is recognized that the above deduction is relatively simplistic and other factors, such as the rate of vaporization of the fuel as a function of temperature, and variations in the start time C will vary from engine to engine as well as from start to start. However, these factors can be compensated for in the computation of the time D which is indicative of the maximum purge speed. Experiments conducted thus far have demonstrated that a clean start can be consistently accomplished when the basic principles discussed above are embodied in the system illustrated in FIG. 2. FIG. 2 is a block diagram of the basic cold start system. An internal combustion engine 10 receives air and fuel from external sources indicated by air delivery system 12 and fuel delivery system 14. The air and fuel delivery systems may be integrated as in a conventional carburetor equipped engine as indicated by dashed line 16 or may be separate entities as in an electronic fuel injection equipped engine. Whether the air and fuel delivery systems are separate entities or are integrated using any of the methods well known in the art, are immaterial to the invention, as long as they provide the required fuel and air in the proper ratio for the operation of the engine. For the purposes of the following discussions, it is assumed that the air and fuel delivery systems are capable of providing the engine with the proper air and fuel for efficient operation including an enriched air-fuel mixture for cold starting and subsequent warm-up period. Numerous types of systems with these capabilities are well known and further discussion is unwarranted for an understanding of the invention. At the initiation of a start attempt, a start air actuator 18 responding to a signal indicative of a start, such as the closing of the ignition switch 20 connected to an electrical power source associated with engine indicated as battery 22. The start air actuator 18 in response to the start signal actuates the air delivery system to deliver a predetermined quantity of air to the engine 10. The start air actuator 18 may set the position of the primary or secondary throttle (not shown) controlling the air flow in the air delivery system or may actuate an auxiliary air delivery system by-passing the throttle. At this point, the method used is immaterial. The fuel delivery system responding to the start air flow delivers the required fuel to effect the starting of the engine. Attached to the engine 10 are a temperature sensor 26 generating a signal indicative of the engine's temperature, and a speed sensor 28 generating a signal indicative of the engine's actual speed. It is acknowledged that these signals may also be derived for the electronic control unit in electrically controlled fuel injection equipped engines and separate sensors may not be required. A reference speed signal generator 30 responds to the temperature signal and generates a reference maximum speed signal indicative of the engine speed that the engine should reach to effectively purge the residual gas from the intake manifold. The reference speed signal along with the actual engine speed signal from speed sensor 28 are transmitted to a comparator 32 which compress the two signals. When the actual speed signal is equal to or greater than the reference speed signal the comparator 32 generates a termination signal which de-energizes the start air actuator 18 and returns the air flow to the engine back to the air delivery system 12 and its attendant accessories in a predetermined manner. A specific embodiment of the start air actuator controlling the throttle position in a conventional air delivery system is illustrated in FIG. 3. The reference numerals indicating the same elements shown in FIG. 2 are the same. Further the fuel delivery system is implied but omitted to simplify the drawing. A partial cross section of the throttle controlled air delivery system 12 is shown. The air delivery system has a throttle body 34 forming a primary air passage 36 ducting air from an external filtered source to the engine 10. In a conventional internal combustion engine the air enters the air delivery system after passing through an air filter (not shown) to remove dust and other contaminant particles from the air before passing to the engine. The use of a filter in connection with the air delivery system in this and subsequently discussed embodiments will be understood. The air flow through the passage 36 is controlled by a rotatable throttle 38 fixedly attached to a pivot shaft 40. The pivot shaft 40 is fixedly attached and rotates with a pivot arm 42. The pivot arm 42 is actuated by the operator's accelerator pedal 44 by means of mechanical linkages symbolically illustrated as dashed line 46 and actuator 48. At one end of the pivot arm 42 is a cam follower illustrated in the form of an idle air adjustment screw 50 which engages the surface of a fast idle cam 52 and controls the position of the throttle 38 when the throttle pedal 44 is in the curb idle position. The operation of the fast idle cam and associated positioning mechanisms are well known in the art and need not be discussed for the purposes of this invention. An electrically activated electromechanical device illustrated as solenoid 54 having a linearly activated armature shaft 56 is disposed to engage the pivot arm 42 at the end opposite the idle screw and place the throttle 38 in the start position when the solenoid is actuated and the armature shaft 56 is extended as shown. The shaft 56 may engage the pivot arm 42 directly as shown, or through appropriate mechanical linkages as may be devised by any person skilled in the art. Power is applied to the solenoid 54 from the engine's electrical power source such as battery 22 through the ignition switch 20 and a normally closed latching relay 58. Closing the ignition switch 20 energizes the solenoid 54 extending shaft 56 thereby rotating pivot arm 42 and opening throttle 38 to provide the desired start air flow. After the engine starts and the speed sensor 28 generates a signal indicative of a speed equal to or greater than the reference speed signal generated by the reference speed generator 30, the comparator 32 generates a signal applied to the latching coil 60 of the relay 58. The magnetic field produced by the coil 60 causes the contact 62 to switch from post 64 to post 66 de-energizing the solenoid 54 and energizing the coil 60 directly from the electrical power source as long as the ignition switch remains closed. With the solenoid de-energized, a biasing means illustrated as spring 68 urges the pivot arm 42 to rotate in a direction (counter-clockwise in the illustration) to cause cam follower 50 to engage cam 52 and the other end of the pivot arm 42 to urge the armature shaft 56 back into the solenoid 54. It is recognized that in some solenoids the armature shaft 56 is spring loaded and will retract automatically when the solenoid is deactivated. The dash pot 70 attached between arm 42 and a stationary member 72 controls the rate at which spring 68 rotates the arm 42 to engage the cam follower 50 with the cam 52. The dash pot 70 by controlling the rotational rate of arm 42 controls the rate at which throttle 38 is closed preventing a sudden closing of the throttle when the solenoid is deactivated and prevents stalling of the engine by a sudden reduction in air flow. It is not necessary that dash pot 70 be connected directly to the arm 42 but may be connected to an element in a connecting linkage associated with armature shaft 56 as shown in FIG. 4 so that once the shaft 56 is retracted into the solenoid, the dash pot 70 is no longer associated with the movement of arm 42 and the throttle functions in a normal manner independent of the dash pot. In FIG. 4 the extendable shaft 56 of solenoid 54 rotates actuator 74 rotatably pivoted at one end about a shaft 76 attached to an ear 78 fixedly attached to a stationary member such as the throttle body 34. When the solenoid 54 is deactivated, the bias spring 68 urges the pivot arm 42 to rotate and urges actuator arm 74 to push armature shaft back into the solenoid. The dash pot 70 is connected between the actuator arm 74 and a stationary member 72 by appropriate linkages and impedes the rotational movement of the throttle 38 to the closed position in response to the biasing force of spring 68. FIG. 5 illustrates the position of the elements shown in FIG. 3 with the solenoid deactivated and the armature shaft 56 in the retracted position after the relay 58 has been actuated by a signal generated by the comparator. As shown in FIG. 5 the contact 62 of the relay 58 is in contact with post 66 and applies battery power directly to the coil 60. The coil 60 holds the relay in this position as long as the ignition switch 20 remains closed. The solenoid is no longer in electrical connection with the electrical power supply 22 and is deactivated. Arm 42 under the force of spring 68 rotates in counter-clockwise direction and cam follower 50 is engaged with fast idle cam 52 closing the throttle to the position determined by the fast idle control of the air delivery system. In this condition with the shaft 56 withdrawn, the air delivery to the engine is controlled by either the fast idle cam when the throttle pedal is in the idle position and by the throttle pedal in any other position. One skilled in the art will quickly recognize that the same or mechanically equivalent approach may be used to control the air flow through a throttle bypass passage when the air delivery system includes such a throttle bypass auxiliary air delivery system. Once one understands the principle of operation, a myriad of mechanical embodiments immediately become obvious. One of such embodiments shown in FIG. 6 uses the spring force of a vacuum 80 motor to initially set the throttle to the start air position prior to a start attempt. With the exception of the vacuum motor, all the elements shown in FIG. 6 are the same as shown in FIG. 2. The vacuum motor 80 has a flexible diaphragm 82 dividing a vacuum motor housing 84 into two chambers 86 and 88. Chamber 86 is vented by means of a hollow member such as tube 90 to the air pressure in the intake manifold of the engine. Chamber 88 is vented to atmospheric pressure. Chamber 86 has a resilient member such as spring 92 urging the flexible diaphragm 82 away from the opposite wall of the chamber. The movement of the diaphragm 82 by the force generated by spring 92 is limited by a stop 94 formed about an aperture 96 in the part of the housing enclosing chamber 88. Attached to the diaphragm 82 and moveable therewith is an actuator shaft 98 extending through the aperture 96 and engaging the pivot arm 42. With the flexible diaphragm against the stop 94 when the engine is stopped and there is no vacuum in the intake manifold the shaft 98 urged by spring 92 engages the pivot arm 42 and sets the position of throttle 38. When the ignition is turned on, solenoid 54 is activated and armature shaft 56 extends and assists vacuum motor spring 92 to hold pivot arm 42 in the start air position. During cranking and prior to the engine starting both the vacuum motor 80 and the solenoid cooperate to hold the throttle in the open position. After the engine starts, a vacuum develops in the intake manifold and by means of tube 90 is communicated to chamber 86 in the vacuum motor. The flexible diaphragm 82 under the influence of atmospheric air pressure in chamber 88 moves against the force of spring 92 and retracts rod 98 from engagement with arm 42. Now pivot arm 42 is only held in position by the solenoid shaft 55 which retracts when the solenoid is deactivated as previously described with reference to FIGS. 2 and 4. The advantage of this system is that the solenoid is only used to hold the throttle in the start position, which requires substantially less power than that required to open the throttle from the closed position as discussed relative to FIG. 2. Alternatively, the solenoid may be used to lock the vacuum motor shaft in the extended position as shown in FIG. 7. FIG. 7 only shows the interrelationship between the vacuum motor and the solenoid while the remainder of the system is as shown in FIG. 3. The vacuum motor 80 as described relative to FIG. 7 has the shaft 98 in the extended position with the flexible diaphragm 82 being urged by spring 92 against the stop 94. The shaft 98 has a notch 100 engaged by a dog 102 on lever 104 pivoted about a shaft 106. The shaft 106 is supported from a stationary member 108 which may be the throttle body or any other stationary member associated with the engine. The dog 102 is biased away from the notch 100 by a resilient means such as a spring 110. When the ignition is turned on, the solenoid 54 is actuated and the armature shaft 56 extends rotating lever 104 against the force of spring 110 and dog 102 engages notch 100 in shaft 98. In this condition the dog 102 prevents the shaft 98 from being retracted even when a vacuum exists in chamber 86. Dog 102 remains engaged with notch 100 until the solenoid 54 is de-energized. De-energizing the solenoid allows spring 110 to retract the dog 102 from notch 110 and shaft 98 will retract due to atmospheric pressure on the flexible diaphragm 82. It would be obvious to a person skilled in the art that the force of the resilient spring and that of the armature shaft could be reversed and the force of the solenoid be used to unlatch the shaft 98. FIG. 8 shows still another alternative method in which the solenoid 54 controls the position of a valve 112 in the vacuum tube 90 between the intake manifold and the vacuum motor 80. The solenoid 54 is energized when the ignition switch 20 is placed in the "ON" position extending armature shaft 56 outwardly. The armature shaft 56 engages a pintle 114 and urges it forward against the force of a resilient member such as spring 116 and comes to stop against valve seat 118. With the pintle 114 seated against the seat 118, the vacuum generated in the intake manifold is prevented from evacuating chamber 86 in the vacuum motor 80 and the shaft 98 remains in its extended position. Deactivation of solenoid 54 by signal generated by the comparator 32 permits the spring 116 to unseat the pintle 114 from seat 118 permitting the vacuum in the intake manifold to evacuate chamber 86. Atmospheric pressure in chamber 88 then moves flexible diaphragm 82 against the force of the spring 92 retracting the shaft 98. The motion of shaft 98 in FIG. 8 is used to control the start air flow in an auxiliary air passage bypassing the throttle 38 in the primary air delivery system 12. The start air is derived from a clean atmospheric pressure air source such as from the air intake air filter or as shown from the primary air delivery system by means of an air entrance passage 120 opening into the primary air passage 36 at a point upstream of the throttle 38. Entrance passage 120 is in the form of a "U" having a valve seat 122 at the terminal end. A valve housing 124 has an aperture 126 adapted to receive the actuator shaft 98 along one leg of the "U"-shaped passage 120. A seal 128 is provided to prevent air leakage. A valve member 130 is fixedly attached to the end of the actuator shaft 98 and moves therewith so that retracting of the actuator shaft by the vacuum motor 80 will cause valve member 130 to seat against the valve seat 122 blocking passage 120. The start air flow is returned to the primary air passage 36 downstream of the throttle 38 by means of exit passage 132. The rate at which the actuator 98 moves valve member 130 to close passage 120 may be controlled by restriction 134 associated with valve 112 as shown or a restriction in vacuum tube 90 controlling the air flow from vacuum motor chamber 86 into the intake manifold. In operation, prior to starting the engine, valve 112 is open and chamber 86 is at atmospheric pressure, therefore, the force of spring 92 extends the actuator shaft 98 unseating valve member 130 from valve seat 122 and start air from upstream of the throttle 38 flows through passages 120 and 132 to a point downstream of the throttle. When the ignition switch is closed indicating a start attempt, solenoid 54 is energized and valve 112 is closed keeping chamber 86 at atmospheric pressure and shaft 98 extended. After the engine reaches the predetermined speed, the solenoid is deactivated and valve 112 opens and the vacuum in the intake manifold causes air to flow from chamber 86. The restriction 134 controls the rate at which the chamber 86 is evacuated and therefore the rate at which shaft 98 retracts valve member 130 to close passage 120. After a predetermined time, valve member 130 seats against valve seat 122 and the start air is terminated. Although the comparator 32 is illustrated as actuating a latching relay, such as relay 58, it is well within the perview of one skilled in the art to substitute solid-state control devices to perform the same function. FIG. 9 shows a portion of the start air servo embodying a bi-stable solidstate flip-flop 136 performing the same function as relay 58. A set signal received by closing the ignition switch 20 places the flip-flop 136 in a first state energizing the solenoid 54. A reset signal generated by the comparator 32 when the actual engine speed equals or exceeds the predetermined speed causes the flip-flop to change state and de-energizes the solenoid. The flip-flop 136 is now locked in the second state until the ignition switch 20 is opened terminating power to the flip-flop preventing re-energization of the solenoid after the engine has been once started and accelerated to the predetermined speed. Although various methods have been disclosed for implementing the invention, the scope of the invention is not limited by the embodiments illustrated. A person skilled in the art will immediately recognize that changes can be made to the illustrated embodiment without departing from the spirit of the invention. For instance, actuation of the solenoid may be initiated by the starter relay rather than the ignition switch or a stepper motor may replace the solenoid or the latching relay or flip-flop may be replaced with alternate solid-state switching circuits. These alternate embodiments are contemplated to be within the scope of the invention.

An auxiliary air control system is disclosed for automatically controlling the air flow to an internal combustion engine during the starting phase of the engine's operational cycle to facilitate clean consistant starts under both hot and cold engine conditions. The system embodies an electrically actuated control providing a predetermined air flow during the cranking and subsequent start of the engine. After the start has been achieved, the engine is permitted to accelerate to a speed determined from the engine's temperature. Thereafter the air flow is reduced in a controlled manner to the normal idle air flow. The system not only facilitates consistent starting of the engine but also substantially reduces the noxious exhaust emissions normally attendant the starting of an internal combustion engine.

REFERENCE TO PENDING PRIOR PATENT APPLICATIONS [0001] This patent application claims benefit of: [0002] (i) pending prior U.S. Provisional Patent Application Ser. No. 61/210,315, filed Mar. 17, 2009 by Julian Nikolchev et al. for JOINT SPACING BALLOON CATHETER (Attorney's Docket No. FIAN-28 PROV); [0003] (ii) pending prior U.S. Provisional Patent Application Ser. No. 61/268,340, filed Jun. 11, 2009 by Julian Nikolchev et al. for METHOD AND APPARATUS FOR DISTRACTING A JOINT, INCLUDING THE PROVISION AND USE OF A NOVEL JOINT-SPACING BALLOON CATHETER AND A NOVEL INFLATABLE PERINEAL POST (Attorney's Docket No. FIAN-42 PROV); [0004] (iii) pending prior U.S. Provisional Patent Application Ser. No. 61/278,744, filed Oct. 9, 2009 by Julian Nikolchev et al. for METHOD AND APPARATUS FOR DISTRACTING A JOINT, INCLUDING THE PROVISION AND USE OF A NOVEL JOINT-SPACING BALLOON CATHETER AND A NOVEL INFLATABLE PERINEAL POST (Attorney's Docket No. FIAN-49 PROV); and [0005] (iv) pending prior U.S. Provisional Patent Application Ser. No. 61/336,284, filed Jan. 20, 2010 by Julian Nikolchev et al. for METHOD AND APPARATUS FOR DISTRACTING A JOINT, INCLUDING THE PROVISION AND USE OF A NOVEL JOINT-SPACING BALLOON CATHETER AND A NOVEL INFLATABLE PERINEAL POST (Attorney's Docket No. FIAN-53 PROV). [0006] The four (4) above-identified patent applications are hereby incorporated herein by reference. FIELD OF THE INVENTION [0007] This invention relates to surgical methods and apparatus in general, and more particularly to methods and apparatus for treating a hip joint. BACKGROUND OF THE INVENTION The Hip Joint in General [0008] The hip joint is a ball-and-socket joint which movably connects the leg to the torso. The hip joint is capable of a wide range of different motions, e.g., flexion and extension, abduction and adduction, medial and lateral rotation, etc. See FIGS. 1A , 1 B, 1 C and 1 D. [0009] With the possible exception of the shoulder joint, the hip joint is perhaps the most mobile joint in the body. Significantly, and unlike the shoulder joint, the hip joint carries substantial weight loads during most of the day, in both static (e.g., standing and sitting) and dynamic (e.g., walking and running) conditions. [0010] The hip joint is susceptible to a number of different pathologies. These pathologies can have both congenital and injury-related origins. In some cases, the pathology can be substantial at the outset. In other cases, the pathology may be minor at the outset but, if left untreated, may worsen over time. More particularly, in many cases, an existing pathology may be exacerbated by the dynamic nature of the hip joint and the substantial weight loads imposed on the hip joint. [0011] The pathology may, either initially or thereafter, significantly interfere with patient comfort and lifestyle. In some cases, the pathology can be so severe as to require partial or total hip replacement. A number of procedures have been developed for treating hip pathologies short of partial or total hip replacement, but these procedures are generally limited in scope due to the significant difficulties associated with treating the hip joint. [0012] A better understanding of various hip joint pathologies, and also the current limitations associated with their treatment, can be gained from a more thorough understanding of the anatomy of the hip joint. Anatomy of the Hip Joint [0013] The hip joint is formed at the junction of the leg and the hip. More particularly, and looking now at FIG. 2 , the head of the femur is received in the acetabular cup of the hip, with a plurality of ligaments and other soft tissue serving to hold the bones in articulating condition. [0014] More particularly, and looking now at FIG. 3 , the femur is generally characterized by an elongated body terminating, at its top end, in an angled neck which supports a hemispherical head (also sometimes referred to as “the ball”). As seen in FIGS. 3 and 4 , a large projection known as the greater trochanter protrudes laterally and posteriorly from the elongated body adjacent to the neck of the femur. A second, somewhat smaller projection known as the lesser trochanter protrudes medially and posteriorly from the elongated body adjacent to the neck. An intertrochanteric crest ( FIGS. 3 and 4 ) extends along the periphery of the femur, between the greater trochanter and the lesser trochanter. [0015] Looking next at FIG. 5 , the hip socket is made up of three constituent bones: the ilium, the ischium and the pubis. These three bones cooperate with one another (they typically ossify into a single “hip bone” structure by the age of 25 or so) in order to collectively form the acetabular cup. The acetabular cup receives the head of the femur. [0016] Both the head of the femur and the acetabular cup are covered with a layer of articular cartilage which protects the underlying bone and facilitates motion. See FIG. 6 . [0017] Various ligaments and soft tissue serve to hold the ball of the femur in place within the acetabular cup. More particularly, and looking now at FIGS. 7 and 8 , the ligamentum teres extends between the ball of the femur and the base of the acetabular cup. As seen in FIGS. 8 and 9 , a labrum is disposed about the perimeter of the acetabular cup. The labrum serves to increase the depth of the acetabular cup and effectively establishes a suction seal between the ball of the femur and the rim of the acetabular cup, thereby helping to hold the head of the femur in the acetabular cup. In addition to the foregoing, and looking now at FIG. 10 , a fibrous capsule extends between the neck of the femur and the rim of the acetabular cup, effectively sealing off the ball-and-socket members of the hip joint from the remainder of the body. The foregoing structures (i.e., the ligamentum teres, the labrum and the fibrous capsule) are encompassed and reinforced by a set of three main ligaments (i.e., the iliofemoral ligament, the ischiofemoral ligament and the pubofemoral ligament) which extend between the femur and the perimeter of the hip socket. See, for example, FIGS. 11 and 12 , which show the iliofemoral ligament, with FIG. 11 being an anterior view and FIG. 12 being a posterior view. Pathologies of the Hip Joint [0018] As noted above, the hip joint is susceptible to a number of different pathologies. These pathologies can have both congenital and injury-related origins. [0019] By way of example but not limitation, one important type of congenital pathology of the hip joint involves impingement between the neck of the femur and the rim of the acetabular cup. In some cases, and looking now at FIG. 13 , this impingement can occur due to irregularities in the geometry of the femur. This type of impingement is sometimes referred to as cam-type femoroacetabular impingement (i.e., cam-type FAI). In other cases, and looking now at FIG. 14 , the impingement can occur due to irregularities in the geometry of the acetabular cup. This latter type of impingement is sometimes referred to as pincer-type femoroacetabular impingement (i.e., pincer-type FAI). Impingement can result in a reduced range of motion, substantial pain and, in some cases, significant deterioration of the hip joint. [0020] By way of further example but not limitation, another important type of congenital pathology of the hip joint involves defects in the articular surface of the ball and/or the articular surface of the acetabular cup. Defects of this type sometimes start out fairly small but often increase in size over time, generally due to the dynamic nature of the hip joint and also due to the weight-bearing nature of the hip joint. Articular defects can result in substantial pain, induce and/or exacerbate arthritic conditions and, in some cases, cause significant deterioration of the hip joint. [0021] By way of further example but not limitation, one important type of injury-related pathology of the hip joint involves trauma to the labrum. More particularly, in many cases, an accident or sports-related injury can result in the labrum being torn away from the rim of the acetabular cup, typically with a tear running through the body of the labrum. See FIG. 15 . These types of injuries can be very painful for the patient and, if left untreated, can lead to substantial deterioration of the hip joint. The General Trend Toward Treating Joint Pathologies Using Minimally-Invasive, and Earlier, Interventions [0022] The current trend in orthopedic surgery is to treat joint pathologies using minimally-invasive techniques. Such minimally-invasive, “keyhole” surgeries generally offer numerous advantages over traditional, “open” surgeries, including reduced trauma to tissue, less pain for the patient, faster recuperation times, etc. [0023] By way of example but not limitation, it is common to re-attach ligaments in the shoulder joint using minimally-invasive, “keyhole” techniques which do not require laying open the capsule of the shoulder joint. By way of further example but not limitation, it is common to repair torn meniscal cartilage in the knee joint, and/or to replace ruptured ACL ligaments in the knee joint, using minimally-invasive techniques. [0024] While such minimally-invasive approaches can require additional training on the part of the surgeon, such procedures generally offer substantial advantages for the patient and have now become the standard of care for many shoulder joint and knee joint pathologies. [0025] In addition to the foregoing, in view of the inherent advantages and widespread availability of minimally-invasive approaches for treating pathologies of the shoulder joint and knee joint, the current trend is to provide such treatment much earlier in the lifecycle of the pathology, so as to address patient pain as soon as possible and so as to minimize any exacerbation of the pathology itself. This is in marked contrast to traditional surgical practices, which have generally dictated postponing surgical procedures as long as possible so as to spare the patient from the substantial trauma generally associated with invasive surgery. Treatment for Pathologies of the Hip Joint [0026] Unfortunately, minimally-invasive treatments for pathologies of the hip joint have lagged far behind minimally-invasive treatments for pathologies of the shoulder joint and the knee joint. This is generally due to (i) the constrained geometry of the hip joint itself, and (ii) the nature and location of the pathologies which must typically be addressed in the hip joint. [0027] More particularly, the hip joint is generally considered to be a “tight” joint, in the sense that there is relatively little room to maneuver within the confines of the joint itself. This is in marked contrast to the shoulder joint and the knee joint, which are generally considered to be relatively “spacious” joints (at least when compared to the hip joint). As a result, it is relatively difficult for surgeons to perform minimally-invasive procedures on the hip joint. [0028] Furthermore, the pathways for entering the interior of the hip joint (i.e., the natural pathways which exist between adjacent bones and/or delicate neurovascular structures) are generally much more constraining for the hip joint than for the shoulder joint or the knee joint. This limited access further complicates effectively performing minimally-invasive procedures on the hip joint. [0029] In addition to the foregoing, the nature and location of the pathologies of the hip joint also complicate performing minimally-invasive procedures on the hip joint. By way of example but not limitation, consider a typical detachment of the labrum in the hip joint. In this situation, instruments must generally be introduced into the joint space using an angle of approach which is offset from the angle at which the instrument addresses the tissue. This makes drilling into bone, for example, significantly more complicated than where the angle of approach is effectively aligned with the angle at which the instrument addresses the tissue, such as is frequently the case in the shoulder joint. Furthermore, the working space within the hip joint is typically extremely limited, further complicating repairs where the angle of approach is not aligned with the angle at which the instrument addresses the tissue. [0030] As a result of the foregoing, minimally-invasive hip joint procedures are still relatively difficult to perform and relatively uncommon in practice. Consequently, patients are typically forced to manage their hip pain for as long as possible, until a resurfacing procedure or a partial or total hip replacement procedure can no longer be avoided. These procedures are generally then performed as a highly-invasive, open procedure, with all of the disadvantages associated with highly-invasive, open procedures. [0031] As a result, there is, in general, a pressing need for improved methods and apparatus for treating pathologies of the hip joint. Current Approaches for Hip Joint Distraction [0032] During arthroscopic hip surgery, it is common to distract the hip joint so as to provide increased workspace within the joint. More particularly, during arthroscopic hip surgery, it is common to unseat the ball of the femur from the socket of the acetabular cup so as to provide (i) improved access to the interior of the joint, (ii) additional workspace within the interior of the joint, and (iii) increased visibility for the surgeon during the procedure. This hip joint distraction is normally accomplished in the same manner that the hip joint is distracted during a total hip replacement procedure, e.g., by gripping the lower end of the patient's leg near the ankle and then pulling the leg distally with substantial force so as to unseat the ball of the femur from the acetabular cup. [0033] However, since the distracting force is applied to the lower end of the patient's leg, this approach necessitates that the distracting force be applied across substantially the entire length of the leg. As a result, the intervening tissue (i.e., the tissue located between where the distracting force is applied and the ball of the femur) must bear the distracting load for the entire time that the hip joint is distracted. [0034] In practice, it has been found that the longer the distracting load is maintained on the leg, the greater the trauma imposed on the intervening tissue. Specifically, it has been found that temporary or even permanent neurological damage can occur if the leg is distracted for too long using conventional distraction techniques. [0035] As a result, the standard of care in the field is for the surgeon to limit the duration of distraction during arthroscopic hip surgery to 90 minutes or less in order to minimize damage to the intervening tissue due to joint distraction. In some situations, this can mean that desirable therapeutic procedures may be curtailed, or even eliminated entirely, in order to keep the duration of the distraction to 90 minutes or less. And even where the duration of the distraction is kept to 90 minutes or less, significant complications can nonetheless occur for many patients. [0036] In addition to the foregoing, in current hip distraction, it is common to use a perineal post to facilitate hip distraction. More particularly, and looking now at FIG. 16 , a perineal post is generally positioned between the legs of the patient so that the medial side of the femur which is to be distracted lies against the perineal post. After the patient's leg is pulled distally (i.e., in the direction of the pulling vector V P ), the leg is adducted so as to lever the leg against the perineal post, which moves the neck and ball of the femur in the direction of the lateral vector V L ; the combination of these two displacements is V D (i.e., the resultant vector of the vectors of V L and V P ). This ensures that the ball of the femur is unseated from the acetabular cup in the desired direction (i.e., in the direction of the resultant vector V D ). [0037] Unfortunately, it has been found that the use of a perineal post can contribute to the damage done to the intervening tissue when the leg is distracted too long. This is because the perineal post can press against the pudendal nerve and/or the sciatic nerve (as well as other anatomy) when distraction occurs. Thus, if the distraction is held too long, neurological damage can occur. This is another reason that the standard of care in the field is for the surgeon to limit the duration of distraction during arthroscopic hip surgery to 90 minutes or less. Additionally, the perineal post can exert pressure on the blood vessels in the leg, and it has been shown that blood flow in these vessels (e.g., the femoral vein, etc.) can be reduced, or in some cases completely occluded, while the hip is in distraction, thus placing the patient in danger of forming deep vein thrombosis or developing other complications. [0038] Additionally, current hip distraction limits the extent to which the leg can be manipulated under distraction during hip arthroscopy, since a substantial pulling force must be maintained on the distal end of the leg throughout the duration of the distraction. Due to this, and due to the fact that there are typically only 2-4 portals available for surgical access into the interior of the hip joint, visualization and access to hip joint pathology and anatomy is frequently hindered. This can limit the extent of surgical procedures available to the surgeon, and can prevent some procedures from being attempted altogether. Procedures such as mosaicplasty and autologous cartilage injection are examples of procedures which require access to extensive areas of the articular surfaces of the femoral head, but which are typically not performed arthroscopically because of the aforementioned access limitations due to leg distraction. [0039] Thus, there is a need for a new and improved approach for distracting the hip joint which addresses the foregoing problems. SUMMARY OF THE INVENTION [0040] These and other objects of the present invention are addressed by the provision and use of a new method and apparatus for distracting a joint. [0041] Among other things, the present invention provides a novel method for distracting a joint and for maintaining distraction of a joint, wherein the novel method minimizes damage to intervening tissue while maintaining distraction of the joint. In addition, the novel method allows visualization of areas in the hip joint that were not previously visible using a conventional hip distraction approach. [0042] The present invention also provides novel apparatus for distracting a joint and for maintaining distraction of a joint, wherein the novel apparatus comprises a novel joint-spacing balloon catheter for maintaining the distraction of a joint. In addition, the novel apparatus preferably includes a novel inflatable perineal post for use in distracting the joint. [0043] In one preferred form of the invention, there is provided a method for creating space in a joint, the method comprising: [0044] applying force to a body part so as to distract the joint and create an intrajoint space; [0045] inserting an expandable member into the intrajoint space while the expandable member is in a contracted condition; [0046] expanding the expandable member within the intrajoint space; and [0047] reducing the force applied to the body part so that the joint is supported on the expandable member. [0048] In another preferred form of the invention, there is provided a method for creating space in a joint, the method comprising: [0049] inserting a first expandable member into the interior of the joint while the expandable member is in a contracted condition; [0050] expanding the first expandable member within the joint so as to create a first intrajoint space; [0051] inserting a second expandable member into the first intrajoint space while the second expandable member is in a contracted condition; and [0052] expanding the second expandable member within the first intrajoint space so as to create a second intrajoint space. [0053] In another preferred form of the invention, there is provided a joint-spacing balloon catheter comprising: [0054] a shaft having a distal end and a proximal end; [0055] an expandable member attached to the distal end of the shaft, the expandable member being capable of supporting opposing bones of a previously-distracted joint when the distraction force is reduced; and [0056] a handle attached to the proximal end of the shaft. [0057] In another preferred form of the invention, there is provided a perineal post comprising a balloon. BRIEF DESCRIPTION OF THE DRAWINGS [0058] These and other objects and features of the present invention will be more fully disclosed or rendered obvious by the following detailed description of the preferred embodiments of the invention, which is to be considered together with the accompanying drawings wherein like numbers refer to like parts, and further wherein: [0059] FIGS. 1A-1D are schematic views showing various aspects of hip motion; [0060] FIG. 2 is a schematic view showing the bone structure in the region of the hip joints; [0061] FIG. 3 is a schematic anterior view of the femur; [0062] FIG. 4 is a schematic posterior view of the top end of the femur; [0063] FIG. 5 is a schematic view of the pelvis; [0064] FIGS. 6-12 are schematic views showing the bone and soft tissue structure of the hip joint; [0065] FIG. 13 is a schematic view showing cam-type femoroacetabular impingement (FAI); [0066] FIG. 14 is a schematic view showing pincer-type femoroacetabular impingement (FAI); [0067] FIG. 15 is a schematic view showing a labral tear; [0068] FIG. 16 is a schematic view showing how a perineal post is used to distract the hip joint in a conventional hip distraction; [0069] FIGS. 17-19 are schematic views showing a novel joint-spacing balloon catheter formed in accordance with the present invention; [0070] FIG. 20 is a schematic flowchart showing one novel aspect of a novel method for distracting a joint; [0071] FIG. 21 is a schematic view showing the novel joint-spacing balloon catheter of FIGS. 17-19 being deployed within a hip joint; [0072] FIG. 22 is a schematic flowchart showing another novel aspect of a novel method for distracting a joint; [0073] FIG. 23 is a schematic view showing how the leg of a patient may be manipulated once the ball of the femur is being supported on the inflated balloon of the joint-spacing balloon catheter, and once the external distracting force previously applied to the distal end of the leg has been released; [0074] FIGS. 23A-23D are schematic views showing an outer guiding member which may be used to deploy the joint-spacing balloon catheter within the joint; [0075] FIGS. 24-28 are schematic views showing how one or more expandable elements may be used to tether the joint-spacing balloon catheter to the capsule of the joint; [0076] FIG. 28A is a schematic view showing another means for stabilizing the joint-spacing balloon catheter within a joint; [0077] FIGS. 29 and 30 are schematic views showing how additional lumens may be provided in the elongated shaft of the joint-spacing balloon catheter in order to accommodate additional structures, e.g., guidewires, obturators, working instruments, optical fibers, etc.; [0078] FIGS. 31-35 are schematic views showing alternative configurations for the balloon of the joint-spacing balloon catheter; [0079] FIGS. 36-38 are schematic views showing additional alternative configurations for the balloon of the joint-spacing balloon catheter; [0080] FIGS. 39-52 are schematic views showing that the joint-spacing balloon catheter may comprise multiple balloons, with those multiple balloons being arranged in a variety of configurations; [0081] FIGS. 53-55 are schematic views showing how a balloon of the joint-spacing balloon catheter may comprise a plurality of separate chambers, with those chambers being arranged in a variety of configurations; [0082] FIGS. 56-60 and 60 A- 60 D are schematic views showing how a balloon of the joint-spacing balloon catheter may incorporate puncture protection within its structure; [0083] FIGS. 61-63 are schematic views showing how a associated structure may be used in conjunction with the joint-spacing balloon catheter so as to provide puncture protection for a balloon of the joint-spacing balloon catheter; [0084] FIGS. 64-72 are schematic views showing how a supplemental structure may be provided within a balloon of the joint-spacing balloon catheter so as to provide fail-safe support in the event that the balloon should lose its integrity; [0085] FIGS. 73-78 are schematic views showing additional mechanisms for expanding a balloon of the joint-spacing balloon catheter; [0086] FIGS. 79 and 80 are schematic views showing an inflatable perineal post provided in accordance with the present invention; and [0087] FIGS. 81 and 82 are schematic views showing another inflatable perineal post provided in accordance with the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Novel Joint-Spacing Balloon Catheter [0088] In one form of the present invention, there is provided a novel joint-spacing balloon catheter for use in distracting a joint, and particularly for maintaining the distraction of a joint, as will hereinafter be discussed in detail. [0089] More particularly, in this form of the invention, and looking next at FIGS. 17-19 , there is shown a novel joint-spacing balloon catheter 5 formed in accordance with the present invention. Novel joint-spacing balloon catheter 5 generally comprises an elongated shaft 10 having a balloon 15 disposed at its distal end and a handle 20 disposed at its proximal end. [0090] Elongated shaft 10 is preferably flexible, and preferably includes an internal stiffener 25 extending along at least a portion of its length so as to facilitate proper positioning of balloon 15 during use. Internal stiffener 25 could comprise a round or rectangular wire (e.g., such as shown in FIG. 19 ), and be made out of a metal (e.g., stainless steel, Nitinol, etc.) or plastic. If internal stiffener 25 comprises a rectangular wire, the short axis of the wire can provide flexibility (e.g., to enable the distal end of the joint-spacing balloon catheter 5 to navigate around the curvature of the femoral head); whereas, the long axis can provide stiffness to better control the position of the balloon in the joint space. If desired, elongated shaft 10 may also include a rigid overshaft 30 adjacent to handle 20 so as to further stiffen the proximal end of elongated shaft 10 , whereby to provide better control for the positioning of balloon 15 . Rigid overshaft 30 can be a stainless steel tube. Rigid overshaft 30 can be about 10 cm to about 30 cm in length, but is preferably about 12.5 cm to about 22.5 cm in length. A steering cable 35 is provided for steering the direction of balloon 15 . More particularly, steering cable 35 extends through elongated shaft 10 between the distal end of elongated shaft 10 and a steering control mechanism 40 provided on handle 20 . By manipulating steering control mechanism 40 , the user is able to steer the direction of balloon 15 , e.g., in the manner shown in FIG. 18 . More particularly, steering control mechanism 40 and steering cable 35 are adapted to cause shaft 10 to arc. This arc can be a radius of about 5 mm to about 10 cm, but is preferably a radius of about 1 cm to about 5 cm. [0091] Balloon 15 is preferably selectively inflatable/deflatable via an inflation/deflation lumen 45 extending through elongated shaft 10 and handle 20 . An inflation/deflation control mechanism 50 is interposed between inflation/deflation lumen 45 and a supply port 55 which is connected to an appropriate fluid reservoir (not shown). By manipulating inflation/deflation control mechanism 50 , the user is able to inflate/deflate balloon 15 as desired. Inflation/deflation control mechanism 50 may comprise a stopcock, a valve, a pump and/or other fluid control mechanisms. Balloon 15 preferably includes an atraumatic tip 60 at its distal end. [0092] On account of the foregoing, joint-spacing balloon catheter 5 may have its balloon 15 set to its deflated state via inflation/deflation control mechanism 50 , the deflated balloon may be advanced to a remote site using handle 20 and steering control mechanism 40 , and then balloon catheter 5 may have its balloon set to its inflated state by further manipulating inflation/deflation control mechanism 50 , whereby to support tissue and maintain the distraction of a joint, as will hereinafter be discussed in detail. Novel Method for Distracting a Joint [0093] In another form of the present invention, there is provided a novel method for distracting a joint, preferably the hip joint, and preferably using novel joint-spacing balloon catheter 5 . [0094] More particularly, in this form of the invention, and looking now at FIG. 20 , the hip joint is first distracted using a standard leg distraction technique, e.g., by positioning a perineal post between the patient's legs, pulling on the distal end of the leg with a substantial force, and then adducting the leg so as to unseat the ball of the femur from the acetabular cup, in the manner described above and shown in FIG. 16 . [0095] Next, joint-spacing balloon catheter 5 , with balloon 15 set in its deflated state, is inserted into the space created between the ball of the femur and the acetabular cup. This may be done under direct visualization (i.e., using an endoscope inserted into the distracted joint), or under fluoroscopy, or both. [0096] Then balloon 15 is inflated. See FIG. 21 . [0097] Next, the distal force which was previously applied to the distal end of the leg is partially or fully released. Release of the full distraction force has the beneficial effect of completely eliminating the tension load imposed on the intervening tissue, whereas a partial release of the distraction force only partially eliminates the tension load imposed on the intervening tissue—however, even such partial release of the distraction force can still meaningfully reduce the tension load imposed on the intervening tissue, and it provides a safeguard in the event that balloon 15 should prematurely deflate, e.g., mid-procedure. The aforementioned partial or full release of the external distraction force allows the ball of the femur to seat itself on the inflated balloon, with the balloon acting as a spacer so as to maintain a desired spacing between the ball of the femur and the acetabular cup. Thus, joint distraction is maintained even though a substantial distraction force is no longer being applied to the distal end of the leg. Since joint distraction can be reliably maintained without the risk of damage to the intervening tissue from a substantial externally-applied distraction force, the traditional concern to complete procedures in 90 minutes or less is substantially diminished, and complications from joint distraction are greatly reduced. This is a very significant improvement over the prior art. [0098] With the joint so distracted, the arthroscopic surgery can then proceed in the normal fashion. [0099] Significantly, and in accordance with another novel aspect of the invention (see FIG. 22 ), the use of joint-spacing balloon catheter 5 can enable the leg to be manipulated while the joint is in a distracted state. More particularly, it has been discovered that, once balloon 15 has been inflated within the joint and the pulling force applied to the distal end of the leg has been partially or fully released, so that the head of the femur is resting on the balloon, the leg can be moved about (i.e., pivoted) on the balloon. Manipulation can include flexion and extension, adduction and abduction, as well as internal and external rotation. See, for example, FIG. 23 . This manipulation of the leg while the joint is in a distracted, balloon-supported state enables more of the joint anatomy and pathology to be visualized and accessed, for superior surgical results. By contrast, a patient's leg cannot be manipulated in this manner when the leg is being distracted in a conventional manner, i.e., by a pulling force applied to the distal end of the leg. Therefore, procedures can be performed using the present invention which cannot be performed using conventional distraction techniques. This is a very significant improvement over the prior art. [0100] Additionally, some procedures which would normally require the creation of an additional portal to access pathology can be accomplished without the creation of the additional portal, thereby reducing the visible scar and potential morbidity of the additional portal. This is also a significant improvement over the prior art. [0101] At the conclusion of the arthoscopic surgery, a distal force is re-applied to the distal end of the leg so as to take the load off the inflated balloon, the balloon is deflated, and then the joint-spacing balloon catheter is removed from the interior of the joint. [0102] Finally, the distal force applied to the distal end of the leg is released, so as to allow the ball of the femur to re-seat itself in its normal position within the acetabular cup. [0103] With respect to the foregoing method of the present invention, it should be appreciated that joint-spacing balloon catheter 5 can be specifically located in the joint space so as to preferentially bias the position of the femoral head relative to the acetabulum when the pulling force on the distal end of the leg is relaxed and the ball of the femur transfers its load to (i.e., is seated on) the inflated balloon. For example, positioning joint-spacing balloon catheter 5 so that balloon 15 is more posterior in the joint causes the femoral head to settle in a more anterior position, which can improve visualization and access to the posterior acetabular rim. [0104] With respect to the foregoing method of the present invention, it should also be appreciated that joint-spacing balloon catheter 5 can be placed in the joint space so as to provide better visualization and access to the peripheral compartment of the hip. [0105] Thus it will be seen that the present invention provides a safe and simple way to significantly reduce trauma to intervening tissue in the leg when practicing leg distraction, since a substantial distally-directed force only needs to be applied to the distal end of the patient's leg long enough for the deflated balloon to be positioned in the distracted joint and for the balloon to thereafter be inflated—the distally-directed distraction force does not need to be maintained on the distal end of the patient's leg during the surgery itself. As a result, trauma to the intervening tissue is greatly reduced, and the surgeon no longer needs to limit the duration of distraction to 90 minutes or less in order to avoid damage to the intervening tissue. This is a very significant improvement over the prior art. [0106] In addition, the use of the present invention enables more of the joint anatomy and pathology to be visualized and accessed, since supporting the ball of the femur on an inflated balloon allows the initial external distraction to be relaxed, and allows the leg to be manipulated on the inflated balloon while the joint is in a distracted state. By contrast, the leg cannot be manipulated in this manner while the leg is being distracted in a conventional manner, i.e., by a pulling force applied to the distal end of the leg. Therefore, arthroscopic procedures can be performed using the present invention which cannot be performed using conventional distraction techniques. This is a very significant improvement over the prior art. [0107] Additionally, some procedures which would normally require the creation of an additional portal to access pathology can be accomplished without the creation of the additional portal, thereby reducing the visible scar and potential morbidity of the additional portal. This is also a significant improvement over the prior art. Further Details of the Joint-Spacing Balloon Catheter [0108] It will be appreciated that balloon 15 preferably serves as a both a spacer and as a pivot support to allow the manipulation of the femur while the joint is distracted. Balloon 15 is constructed so as to be atraumatic in order to avoid damaging the anatomy, including the cartilage surfaces of the joint. At the same time, and as will hereinafter be discussed in further detail, balloon 15 may be appropriately textured and/or sculpted in order to maintain its position within the joint, preferentially to either one of the acetabulum or femur, while still allowing the opposing bone to move smoothly over the balloon surface. [0109] In one preferred form of the invention, elongated shaft 10 has an outer diameter of about 0.040″ (or less) to about 0.250″ (or more). An outer diameter of approximately 0.120″ to 0.200″ is preferred for many hip applications. [0110] If desired, a retractable sheath (not shown) may be provided over shaft 10 in order to cover balloon 15 prior to inflation. [0111] And if desired, the distal end of shaft 10 can be pre-shaped with a bend so as to give joint-spacing balloon catheter 5 a directional bias at its distal end. [0112] Furthermore, if desired, and looking now at FIGS. 23A-23D , an outer guiding member 57 may be provided for directing joint-spacing balloon catheter 5 to a location within the joint. More particularly, in this form of the invention, outer guiding member 57 comprises a central lumen 58 sized to receive joint-spacing balloon catheter 5 ; the outer guiding member is advanced into position within the joint, and then joint-spacing balloon catheter 5 is advanced down the central lumen 58 of outer guiding member 57 so that the distal end of joint-spacing balloon catheter 5 is properly disposed within the interior of the joint. [0113] More particularly, FIG. 23A is a schematic view showing an outer guiding member 57 which may be used to deploy joint-spacing balloon catheter 5 within the joint. In many instances, the portal location does not directly align with the entrance of the joint space (i.e., with the acetabular rim region). Outer guiding member 57 has a curve at its distal end which can be aligned with the entrance of the joint space, thus facilitating the delivery of joint-spacing balloon catheter 5 into the interior of the joint space. The joint-spacing balloon catheter 5 is advanced through the central lumen 58 of outer guiding member 57 and exits in a direction which better facilitates navigating the distal end of the joint-spacing balloon catheter around the femoral head. The joint-spacing balloon catheter 5 could have a pre-shaped distal end that further enables guidance into the joint space. Alternatively, joint-spacing balloon catheter 5 could be steerable as discussed above. In practice, outer guiding member 57 is placed such that the distal tip of the outer guiding member is at or near the joint entrance ( FIGS. 23C and 23D ). Alternatively, the distal end of outer guiding member 57 can be placed within the joint space. The distal tip of outer guiding member 57 is oriented in the desired direction for proper placement of the balloon. Joint-spacing balloon catheter 5 is advanced through the central lumen 58 of outer guiding member 57 and into the joint space until balloon 15 is in the desired location (the arrows in FIGS. 23C and 23D indicate direction of balloon catheter delivery). The outer guiding member can be used to help adjust the final balloon position. The outer guiding member 57 can be left in place during the procedure to help tether the joint-spacing balloon catheter in position within the joint. Additionally, outer guiding member 57 can provide a conduit to remove the joint-spacing balloon catheter from the body. [0114] In one preferred form of the invention, balloon 15 is preferably approximately 28 mm in diameter, although it can also range from about 10 mm (or less) in diameter to about 50 mm (or more) in diameter if desired. Furthermore, the length of balloon 15 is preferably approximately 50 mm, although it can also range from about 10 mm (or less) in length to about 75 mm (or more) in length if desired. In this respect, it will be appreciated that balloons of various sizes may be used to address patients of different sizes, variations in anatomy, and/or different pathologies. [0115] Balloon 15 may be inflated with a pressure of up to about 1000 psi, and is preferably inflated with a pressure of up to about 200 psi, and is most preferably inflated with a pressure of up to about 100 psi. In this respect it will be appreciated that it is generally accepted that a force of about 50-80 lbs. is sufficient to distract the hip joint. In order for joint-spacing balloon catheter 5 to support this force, it must provide sufficient pressure over a sufficient surface area (force=pressure X area). Although there are a number of different balloon sizes and operating pressures which can be envisioned, there are limitations on the balloon size and pressure to consider. On the one hand, the balloon must be large enough to cover a sufficient amount of cartilage such that the pressure on the cartilage is lower than that which would damage the cartilage. On the other hand, the balloon must be small enough so as to permit access to and visualization of the operative areas. Hence, there is an optimal range of balloon size and operating pressure, and this optimal range is dependent on tissue dynamics. [0116] In one preferred form of the invention, balloon 15 is fabricated so as to be semi-compliant, although it can also be fabricated so as to be compliant or non-compliant if desired. Examples of semi-compliant balloon materials are polyurethane, nylon and polyether block amide (PEBA). An example of a compliant balloon material is silicone rubber. An example of a non-compliant balloon material is polyethylene terapthalate (PET). A compliant or semi-compliant balloon is generally preferred since it will deform under load to the shape of the surface which the balloon is contacting in order to help distribute load onto that surface. A semi-compliant balloon is generally most preferred since it will retain some aspects of its pre-load shape even when under load, which can be helpful in directing or maintaining bone positioning, particularly when the leg is being manipulated while in a distracted state. The thickness of the balloon material is preferably in the range of about 0.001″ to about 0.020″, and is most preferably between about 0.002″ and about 0.012″. The durometer of the balloon material is preferably in the range of about 30 Shore A to about 85 Shore D, and is most preferably between about 40 Shore D and about 85 Shore D. [0117] If desired, the surfaces of balloon 15 can be textured (e.g., with dimples, ridges, etc.) or covered with another material (e.g., a coating or covering) so as to prevent slippage of the balloon along cartilage when the balloon is being used to support a joint. At the same time, this surface texture or non-slip covering is configured so as to engage the cartilage without causing cartilage damage. In one preferred form of the invention, only a portion of the outer surface of the balloon is textured or covered with a non-slip material. For example, the portion of the balloon which faces the acetabulum could be textured or covered with a non-slip material, but the portion of the balloon which faces the femoral head could be non-textured or non-covered, so as to keep the surface facing the acetabulum from slipping while allowing the surface facing the femoral head to slide relative to the femoral head. In another preferred form of the invention, a majority of the balloon surface is textured or covered with a non-slip material. In yet another preferred form of the invention, two or more different textures or non-slip coverings are provided on the outer surface of the balloon, e.g., depending on the particular cartilage surface which they may engage. [0118] In yet another embodiment of the invention, the balloon is covered with a low friction material which enables slippage of the joint surface on the balloon. The low friction material may cover some or all of the balloon surface. [0119] The balloon may comprise both low slippage and low friction coverings if desired. [0120] Furthermore, if desired, fluoroscopic markings can be incorporated into or disposed on elongated shaft 10 , or incorporated into or disposed on balloon 15 , or incorporated into or disposed on another part of joint-spacing balloon catheter 5 , so as to render the apparatus visible under X-ray. Such fluoroscopic markings may comprise radiopaque ink applied to the apparatus, radiopaque bands applied to the apparatus, radiopaque material incorporated in the construction of the apparatus, and/or a radiopaque fluid used to inflate the balloon (such as a contrast agent). By way of example but not limitation, a radiopaque band material could comprise platinum. By way of further example but not limitation, a radiopaque fluid could comprise a contrast agent such as Dodecafluoropentane. [0121] In one preferred form of the invention, balloon 15 is preferably inflated with a liquid medium, e.g., saline; however, it could also be inflated with a gaseous medium, e.g., air. Among other things, the balloon can be inflated with a high viscosity fluid. This latter construction may be beneficial in the event of a balloon puncture as it would slow the pace of balloon deflation. If desired, a fluid could be used which changes viscosity when subject to changes in temperature, electrical charge, magnetic field, or other means. Alternatively, the balloon can be filled with a compound which increases in viscosity when exposed to saline. This latter construction can be advantageous in certain circumstances, e.g., during a balloon puncture, the escaping fluid would react to the saline present in the joint and could at least partially seal the puncture hole in the balloon. [0122] Where balloon 15 is inflated with a gaseous medium, and that gaseous medium is air, inflation/deflation control mechanism 50 may comprise a pump, and supply port 55 may be open to the atmosphere. [0123] In one aspect of the invention, and looking now at FIGS. 24-28 , joint-spacing balloon catheter 5 further comprises one or more expandable elements 60 in addition to balloon 15 . These expandable elements 60 can be another balloon, a collapsible braid, and/or some other structure which can expand when desired to a larger dimension. Expandable element 60 can be used to releasably secure joint-spacing balloon catheter 5 to the joint capsule. In one embodiment, and as shown in FIG. 24 , an expandable element 60 is located at the distal end of the joint-spacing balloon catheter. This expandable element 60 is expanded once the distal end of the balloon catheter (and the expandable element 60 ) has passed through the capsule 62 at the far side of the joint, so that the expandable element is deployed on the far side of the capsule, whereby to stabilize balloon 15 within the joint. See FIG. 25 . In another embodiment, a second expandable element 60 is expanded adjacent to the internal surface of the far capsule, as shown in FIG. 26 , so that the far side of the capsule is sandwiched between the two expandable elements 60 , whereby to further stabilize balloon 15 within the joint. In this respect it should be appreciated that the two expandable elements 60 may or may not be expanded simultaneously. In yet another embodiment, and looking now at FIG. 27 , one or more expandable elements 60 are disposed proximal to the balloon, to tether the joint-spacing balloon catheter to capsule 62 at the proximal portion of the joint, such as is shown in FIG. 28 . [0124] In another embodiment ( FIG. 28A ), a second cannula 63 is used to secure the distal end of joint-spacing balloon catheter 5 relative to the anatomy. More particularly, the distal tip of the joint-spacing balloon catheter, or a flexible element 64 which extends from the distal end of the joint-spacing balloon catheter (e.g., a guidewire), is passed into the tip of the second cannula 63 . The flexible element could be a wire, a suture, a ribbon, a catheter, a braid, or some other construction which is flexible or semi-flexible. The flexible element 64 can be received within the second cannula or, if desired, gripped within the second cannula. A gripping feature (not shown) could be provided in the second cannula to achieve this. Alternatively, the flexible element 64 could pass entirely through the second cannula. In any case, this construction results in the tip of joint-spacing balloon catheter 5 being stabilized in position by the second cannula 63 . [0125] Additionally, and looking now at FIG. 29 , another lumen 65 can be provided for a guidewire, obturator, light fiber, electrical wire, or the like, or as an additional inflation lumen, etc. And, as shown in FIG. 30 , further lumens 70 can be provided for working instruments, etc. If desired, a pre-shaped guidewire or obturator can be placed through one of the lumens of elongated shaft 10 in order to bias the tip direction of the joint-spacing balloon catheter 5 as the joint-spacing balloon catheter is advanced over the pre-shaped guidewire or obturator. Alternatively, a second steerable wire can be placed through one of the lumens, so as to enable steering of the balloon catheter in a second direction. [0126] To improve resistance to kinking, or to provide the shaft with the desired stiffness and torsional characteristics, a braid or coil 71 ( FIG. 30 ) could be incorporated into the catheter. The braid or coil could comprise a stainless steel wire, a Nitinol wire, etc. Braid or coil 71 could be incorporated at any section of joint-spacing balloon catheter 5 , but is preferably located in at least the flexible section of the catheter. [0127] In FIGS. 17-19 , balloon 15 is shown with a generally cylindrical configuration. However, if desired, balloon 15 can have different configurations. Thus, for example, and looking now at FIGS. 31 and 32 , balloon 15 can comprise a pair of opposing flat surfaces 72 ; or, and looking now at FIGS. 33 and 34 , balloon 15 can have an hourglass shape which includes an intermediate section 73 of reduced diameter; or, and looking now at FIG. 35 , balloon 15 can have a generally hourglass shape with a pair of opposing flat surfaces 72 . The aforementioned hourglass shapes, although depicted symmetrical, can also be asymmetric. For example, one end of the hourglass-shaped balloon may be of a larger dimension (length, diameter, etc.) than the other end of the hourglass-shaped balloon. [0128] Balloon 15 may also be in the form of an arc or other curvature (i.e., a geometry where one side has a greater curvature than the other side), or some other shape (e.g., U-shaped), so as to fit around the ligamentum teres. See FIG. 36 . Additionally, balloon 15 could have the shape of a torus, so as to provide a seat for the ball of the femur. See FIGS. 37 and 38 . [0129] It is also possible to provide joint-spacing balloon catheter 5 with more than one balloon 15 . Where more than one balloon is provided, the balloons can be disposed in series (i.e., end-to-end, such as is shown in FIG. 39 ), or in parallel (such as shown in FIGS. 40 and 41 ), with or without complementary geometries (such as shown in FIGS. 42 and 43 ), or combinations of such geometries (such as shown in FIG. 44 ), or toroidal (such as is shown in FIG. 45 ), etc. The shafts of the multiple balloons may be separated at their distal end (such as is shown in FIG. 40 ) or may be joined at their distal ends (such as is shown in FIG. 41 ). Multiple balloons may be of the same construction, or they may be of different constructions. For example, multiple balloons may be of different sizes, shapes, materials, compliances, coatings, surface textures, coverings, colors, and/or other aspects of construction. Additionally, the multiple balloons may be inflated to different pressures and/or volumes. [0130] These multiple balloons 15 can also be disposed in a mutually-supporting configuration, as shown in FIGS. 46-52 . By arranging the multiple balloons 15 in a mutually-supporting configuration, the multiple balloons 15 may better conform to the acetabulum and femoral surfaces, which would be beneficial in order to reduce pressure on the cartilage and/or to help maintain the balloons in position within the joint space (i.e., to prevent slipping). In this form of the invention, a balloon catheter 5 could have an assembly of balloons 15 that would collectively act as a compliant or semi-compliant device even though the individual balloons are non-compliant, or vice versa. An additional benefit of arranging the multiple balloons 15 in a mutually-supporting configuration is that if one of the balloons deflates, the other balloons can still maintain a substantial portion of the joint space. In one preferred construction, the balloons 15 can slide against each other to spread out, e.g., to spread out in a lateral direction. Where joint-spacing balloon catheter 5 comprises multiple balloons 15 , preferably, a separate inflation/deflation lumen is provided for each balloon, so that each balloon can be separately inflated or deflated, although a single inflation/deflation lumen could be used to simultaneously inflate/deflate more than one balloon. By permitting each balloon of a group of balloons to be selectively inflated, the surgeon can influence the manner in which the ball of the femur is supported relative to the acetabular cup. In one preferred manner of use, each of the balloons may be inflated to a different volume (and/or pressure) than others of the balloons. This approach can be used to impart a specific shape to the overall balloon structure. Also, some of the balloons 15 can be made compliant, and others non-compliant, so as to achieve a desired pressure distribution and/or shape for the overall balloon structure. [0131] It is also possible to provide each of the balloons 15 with a plurality of separate internal chambers 75 ( FIGS. 53-55 ). Preferably each of these separate chambers 75 can be selectively inflated so as to influence the manner in which the ball of the femur is supported relative to the acetabular cup. Thus, in this sort of construction, selective inflation of the various chambers can be used to adjust the position of the ball of the femur within the acetabular cup when the pulling force on the distal end of the leg is relaxed. The use of multiple chambers may also provide a safer design. More particularly, in the event that one of the chambers 75 is punctured during a procedure, the use of multiple chambers 75 may permit some joint distraction to be maintained, thus reducing the chances that, for example, an instrument will be wedged between the femoral head and acetabulum. [0132] If desired, balloons 15 can be formed so as to be puncture resistant in order to minimize the possibility of inadvertently deflating the balloon, e.g., with an errant surgical instrument. To this end, and looking now at FIG. 56-59 , a balloon 15 can embed, or sandwich, a puncture-resistant structure 80 (e.g., a coil or mesh or strand or braid formed out of Nitinol, or stainless steel, or a polymer, etc.) between two layers of material (preferably a non-abrasive elastomer). Alternatively, the puncture-resistant structure 80 could be placed on one side of, or embedded within, a single sheet of material, such as is shown in FIG. 60 . This puncture-resistant structure 80 may be a separate element added to the wall of the balloon or a coating applied to the wall of the balloon. The puncture-resistant structure 80 may also be a layer of material within the side wall of the balloon; for example, the outer layer may be a puncture-resilient material (such as polyurethane) to enhance puncture resistance, while the inner layer material maintains the balloon pressure (such as PET). In one preferred construction, puncture-resistant structure 80 covers a substantial portion of the balloon surface. In another preferred construction, the puncture-resistant structure 80 covers a smaller portion of the balloon surface; in this instance, the surface incorporating the puncture-resistant structure 80 is disposed on the side of the balloon where instruments are used (which could puncture the balloon). [0133] Furthermore, if desired, and looking now at FIGS. 60A-60D , the distal end of joint-spacing balloon catheter 5 could include a shroud 82 disposed over balloon 15 . Shroud 82 may be formed out of a puncture-resistant material so as to protect balloon 15 from inadvertent puncture. Additionally, and/or alternatively, shroud 82 could be formed so as to define the volume created within the joint when balloon 15 is inflated. This construction can be advantageous where balloon 15 is formed out of a compliant material and it is desired to control the manner in which space is created within the joint, i.e., by using a non-compliant or semi-compliant shroud 82 . Additionally, and/or alternatively, shroud 82 could be formed out of a material which provides slippage (e.g., it can be formed out of ePTFE). This can be beneficial in a number of ways. First, it can facilitate easier delivery of the balloon into the joint, including passage through the entry cannula. In a similar way, shroud 82 can also facilitate easier removal of the joint-spacing balloon catheter from the joint, including through the entry cannula. By having enhanced slippage properties, shroud 82 can also facilitate joint manipulation on the balloon. The shroud's geometry (e.g., tapered ends) can also facilitate ease of delivering and removing the joint-spacing balloon catheter to and from the joint space; this may be particularly beneficial if the balloon catheter goes through an entry cannula. Alternatively, the shroud 82 could be formed out of a material which prevents slippage on the joint surface (e.g. a low durometer elastomer). This can be beneficial to enable the balloon to remain stationary on the joint surfaces once it has been placed in the joint space. Additionally, and/or alternatively, shroud 82 can be constructed so as to provide better endoscopic visualization of the balloon; for example, shroud 82 can be an opaque color. [0134] Alternatively, and looking now at FIGS. 61-63 , a shield 85 could be placed alongside balloon 15 to protect the balloon from being punctured from that direction. Shield 85 is preferably introduced into the joint after the balloon has been inserted and inflated, but shield 85 could also be inserted into the joint prior to that if desired. Shield 85 could be made out of a material similar to the puncture-resistant structure 80 described above. [0135] Alternatively, and looking now at FIGS. 64-68 , a balloon-within-a-balloon configuration can be used to provide one or more secondary “fail-safe” (or “safety”) balloons 90 within the primary balloon 15 —such a construction can minimize the risk that joint distraction will be lost in the event that the primary balloon 15 is inadvertently deflated, e.g., by an accidental puncture. If desired, the inner balloon 90 can be made of a different material than the outer balloon 15 . In one preferred construction, inner balloon 90 is non-compliant and outer balloon 15 is semi-compliant. The inner and outer balloons could also have different wall thicknesses, geometries, or other aspects of construction as discussed above. [0136] Alternatively, a different type of secondary structure can be deployed in balloon 15 in order to prevent balloon 15 from completely collapsing in the event that it is punctured. In one embodiment, and looking now at FIG. 69 , a wire 95 is delivered into the interior of the balloon and fills up a portion of the internal balloon volume; in the event that the balloon is punctured, wire 95 provides support to prevent the joint space from collapsing. Wire 95 is preferably made of Nitinol, but could also be formed out of another metal or polymer if desired. In another embodiment, and looking now at FIG. 70 , a wire 100 is delivered across the length of the balloon and set in a bowed configuration. The bowed wire 100 provides mechanical support in the event the balloon is punctured. In FIG. 71 , an exemplary mechanical scaffold 105 is shown deployed in the interior of the balloon so as to provide a safety mechanical support. In FIG. 72 , an expandable foam 110 is deployed within the interior of the balloon; foam 110 expands to fill some or most of the internal balloon space. In one embodiment, expandable foam 110 absorbs fluid and will therefore absorb saline within the balloon. This construction can reduce the speed at which a punctured balloon will deflate. [0137] In yet another embodiment ( FIGS. 73 and 74 ), the balloon is filled with beads 115 . Beads 115 could be absorbent polymer or foam, or non-absorbent. As shown in FIGS. 75-77 , if beads 115 are non-absorbent, the balloon's inflation fluid can be evacuated from the balloon after beads 115 have been introduced into the inflated balloon, leaving a compact “bean bag” structure to maintain the joint space. As shown in FIG. 78 , beads 115 are preferably delivered into the interior of the balloon in a strand configuration, i.e., mounted on a filament 116 . This approach has the additional advantage that, in the event that the balloon should lose its integrity, beads 115 can be safely removed without leaving any beads in the hip joint, i.e., by pulling proximally on filament 116 . If desired, beads 115 can be disposed between a primary outer balloon 15 and secondary inner balloon 90 . [0138] If desired, joint-spacing balloon catheter 5 can include pressure regulation, e.g., a release valve (not shown) to ensure that a balloon is not inflated beyond a maximum level, or an alarm or other alert (not shown) to advise the user that a balloon has been inflated beyond a pre-determined level. This can be important to avoid damage to the patient's tissue or to reduce the risk of inadvertent balloon rupture. [0139] Furthermore, a check valve (not shown) may be installed on the inflation port(s) 55 to enable joint-spacing balloon catheter 15 to be disconnected from the fluid reservoir while maintaining pressure in balloon 15 . [0140] It is also possible to place markings (e.g., longitudinal lines) along the body of balloon 15 , or to color the balloon material, so as to improve endoscopic visualization of the balloon, including to show the degree of balloon inflation. Alternatively, the fluid used to inflate the balloon could be colored, or the balloon surface could have texture, in order to aid visualization of the balloon. [0141] Alternatively, a transparent, thick-walled balloon 15 can be used to increase visualization of the balloon by increasing the refraction of light, which will make the balloon foggy in appearance. Alternatively, a coating could be applied to the balloon material which improves the endoscopic visualization of the balloon. Alternatively, a second balloon or an expandable extrusion could be placed over the primary balloon so as to improve endoscopic visualization. The second balloon and/or expandable extrusion may be colored for improving endoscopic visualization. This configuration can also add to the puncture resistance of the primary balloon and assist in the delivery and retrieval of the primary balloon. [0142] The joint-spacing balloon catheter 5 may also comprise a sensor (not shown). The sensor can measure the temperature of the surrounding tissue or fluid in the joint (e.g., the sensor may be a temperature sensor). The sensor may also detect characteristics of the adjacent cartilage, such as thickness, density, and/or quality (e.g., the sensor may be an ultrasound device, etc.). The sensor could be located on shaft 10 or on balloon 15 , or on another portion of joint-spacing balloon catheter 5 . External Distraction of the Limb [0143] In the foregoing description, the external distraction of the limb is generally discussed in the context of applying a distally-directed distraction force to the distal end of the leg. However, it should be appreciated that the distally-directed distraction force may be applied to another portion of the leg, e.g., to an intermediate portion of the leg, such as at or about the knee. Thus, as used herein, the term “distal end of the leg” is meant to include substantially any portion of the leg which is distal to the ball of the femur, such that by applying the external distraction force to the leg, a tension load is imposed on the intervening tissue. Furthermore, as used herein, the term “intervening tissue” is intended to mean the tissue which is interposed between the location where the external distraction force is applied to the leg and the ball of the femur. Inflatable Perineal Post [0144] The present invention also preferably comprises the provision and use of a novel inflatable perineal post for facilitating joint distraction. [0145] More particularly, and looking now at FIGS. 79 and 80 , there is shown an inflatable perineal post 120 which generally comprises a relatively narrow, substantially rigid inner core 125 surrounded by a relatively wide, substantially soft inflatable balloon 130 . In an alternative embodiment as is shown in FIGS. 81 and 82 , inflatable perineal post 120 comprises a soft inflatable balloon 130 is supported on one or more sides by a substantially rigid support structure 135 . Such a non-cylindrical construction, with inflation being directed along selected directions, can be highly beneficial, since it can reduce engagement of the non-working portions of the perineal post with patient anatomy (e.g., the genitalia). Still other post shapes and configurations can be envisioned by one skilled in the art in view of the present disclosure. [0146] The inflatable balloon 130 of the inflatable perineal post 120 is preferably constructed out of a semi-compliant material, but it could also be compliant or non-compliant. The inflatable balloon 130 of the inflatable perineal post 120 may involve a covering (not shown) for contact with the patient; this covering may be a non-slip material. The inflatable balloon 130 is preferably inflated with a manual or electric pump. The inflatable perineal post 120 could include a read-out panel displaying the balloon pressure. [0147] The inflatable perineal post 120 may also comprise physiologic sensors (not shown) for monitoring parameters such as patient skin temperature and blood flow. Such parameters may be reflective of patient conditions of interest to the surgeon, e.g., a falling patient skin temperature is frequently indicative of reduced blood flow. These physiologic sensors could be incorporated into the surface of the balloon, or they could be separate sensors which are included as part of a kit provided with the inflatable perineal post. The physiologic sensors are adapted to be connected to a monitor so as to provide read-outs on the monitor. [0148] In use, the deflated perineal post balloon is positioned between the patient's legs, the joint is distracted by pulling on the distal end of the leg so that the ball of the femur is spaced from the acetabular cup, the perineal post balloon is inflated, a joint-spacing balloon catheter 5 is inserted into the distracted joint, the balloon 15 is inflated, the force applied to the distal end of the leg is relaxed so that the ball of the femur settles back down onto the one or more inflated balloons 15 , and then the perineal post balloon 130 is at least partially deflated. At this point the arthroscopic surgery can be conducted without trauma to the patient's tissue, due to either the distal distraction of the leg or due to engagement of the perineal post with the tissue of the patient. At the conclusion of the surgery, the distal end of the leg is pulled distally again, the perineal post balloon 130 is inflated, the joint-spacing balloon 15 is deflated, the joint-spacing balloon catheter 5 is removed from the joint, and the joint is reduced. Alternatively, the perineal post balloon could be inflated prior to pulling on the distal end of the leg. Or, alternatively, the perineal post balloon 130 could be deflated prior to withdrawal of the force being applied to the distal end of the leg. In some cases, only one of either (i) pulling on the leg, or (ii) inflating of the perineal post is performed in order to remove or re-position the joint-spacing balloon. [0149] If desired the inflatable perineal post 120 may be used to replace a standard perineal post, and is used in conjunction with a standard traction table; in other words, in this form of the invention, the inflatable perineal post 120 is not used in conjunction with a joint-spacing balloon catheter 5 . One Preferred Form of the Invention [0150] In one preferred form of the present invention, the aforementioned novel method for distracting the joint is implemented using the aforementioned novel joint-spacing balloon catheter 5 and the aforementioned inflatable perineal post 120 . [0151] More particularly, in this form of the invention, the hip joint is first distracted by pulling on the distal end of the leg just above the ankle, and then inflating the inflatable perineal post, where the perineal post is positioned between the patient's legs. The leg may be adducted so as to lever the femur laterally. Alternatively, the inflatable perineal post could be inflated prior to the distal end of the leg being pulled distally. [0152] Next, the surgeon identifies a portal location for joint-spacing balloon catheter delivery. Then a needle is placed into the joint, the stylet is removed, a guidewire is delivered through the needle, and then the needle is removed. The guidewire can be placed in the desired delivery path of the joint-spacing balloon catheter 5 . [0153] An arthroscopic cannula or outer guiding member may then be emplaced if desired; in this instance, the guidewire may be removed if desired. [0154] Next, a joint-spacing balloon catheter 5 of the appropriate size is selected from a kit providing a range of differently-sized joint-spacing balloon catheters. Then the joint-spacing balloon catheter 5 is delivered over the guidewire (either percutaneously or through a cannula) to the target site between the femoral head and the acetabulum. The joint-spacing balloon catheter 5 may be rotated as appropriate if there is asymmetry in the balloon's shape. Alternatively, the joint-spacing balloon catheter 5 may be delivered through a cannula without the use of a guidewire. [0155] Next, a syringe (or other inflation device) is secured to the joint-spacing balloon catheter 5 , and the balloon 15 is inflated to the desired pressure and/or size. If there is more than one balloon 15 , the additional balloon(s) can be inflated. If the additional balloon(s) are used to affect the direction of joint spacing, the pressure and/or size of each balloon is adjusted so as to achieve the desired joint spacing direction. [0156] Once the balloon has been inflated to the desired pressure and/or size, the distraction force applied to the leg is at least partially removed, allowing the head of the femur to rest on the inflated balloon (which is itself supported by the acetabulum). [0157] Additionally, the inflatable perineal post 120 is deflated as appropriate; this could occur before the leg distraction force is released. [0158] The balloon 15 can be re-positioned by re-applying distraction force to the leg and/or re-inflating the inflatable perineal post 120 , deflating balloon 15 and re-positioning the joint-spacing balloon catheter 5 , re-inflating the balloon of the joint-spacing balloon catheter, then releasing the leg distraction and/or deflating the inflatable perineal post. The balloon 15 may be placed in a location which directs the distraction in a preferred direction. Alternatively, where the joint-spacing balloon catheter comprises a plurality of balloons, the balloons may be inflated to different sizes and/or pressures in order to direct the joint distraction in a preferred direction. [0159] With the balloon maintaining the joint distraction, the leg may be manipulated (i.e. rotated, flexed, etc.) in order to visualize and access pathology through the established portals. [0160] Then the arthroscopic surgery is conducted. The leg may be manipulated a number of times through the procedure in order to visualize, access and treat pathology. [0161] At the conclusion of the arthroscopic surgery, the hip joint is distracted again, e.g., by pulling on the distal end of the leg just above the ankle, so as to lift the head of the femur off the balloon. The perineal post balloon may be inflated. The balloon 15 of the joint-spacing balloon catheter is deflated and the joint-spacing balloon catheter is removed. Thereafter, the distraction force applied to the leg may be removed, allowing the head of the femur to settle back on the acetabulum. [0162] In another form of the invention, while the distal end of the leg is held stationary, the perineal post 120 is inflated to break the suction seal of the hip joint and enable the joint-spacing balloon catheter 5 to be placed in the joint and inflated. In this case, no pulling on the leg is performed. This would have the benefit of eliminating a piece of equipment from the surgery and reducing the corresponding surgical time associated with using that equipment. [0163] In yet another form of the invention, the joint-spacing balloon catheter 5 can perform some or all of the joint distraction. In one embodiment, a first joint-spacing balloon catheter 5 is placed adjacent to the femoral head and the balloon is inflated. The leg is then manipulated in abduction or adduction (depending on balloon location), thus levering the femoral neck against the balloon. This levering creates a gap at the acetabular rim. A second joint-spacing balloon catheter 5 is then inserted into the gap and delivered into the joint space (the space between the femoral head and the acetabulum). The balloon of the second joint-spacing balloon catheter is then inflated and distracts the joint; that is, opens up the joint space. In one embodiment, the first balloon is placed on the lateral/superior aspect of the femoral neck. Once the second balloon is inflated, the first balloon can be deflated and withdrawn. The first balloon may be of a different size and shape as the second balloon. It also may be inflated to a different pressure. Kits [0164] The joint-spacing balloon catheter 5 and the inflatable perineal post 120 may be offered as part of a single kit. A guidewire or obturator, outer guiding member and a balloon inflation device may additionally be provided. Use of the Present Invention for Other Applications [0165] It should be appreciated that the present invention may be used for distracting the hip joint in an open, more invasive procedure. The present invention can also be used in hip joint pathologies where joint distraction is not needed but space creation is needed, e.g., to visualize and/or to address pathologies in the peripheral compartment or pathologies in the peritrochanteric space. Additionally, the present invention may be used for distracting joints other than the hip joint (e.g., it may be used to distract the shoulder joint). Modifications of the Preferred Embodiments [0166] It should be understood that many additional changes in the details, materials, steps and arrangements of parts, which have been herein described and illustrated in order to explain the nature of the present invention, may be made by those skilled in the art while still remaining within the principles and scope of the invention.

A method for creating space in a joint, the method comprising: applying force to a body part so as to distract the joint and create an intrajoint space; inserting an expandable member into the intrajoint space while the expandable member is in a contracted condition; expanding the expandable member within the intrajoint space; and reducing the force applied to the body part so that the joint is supported on the expandable member.

CROSS REFERENCE TO RELATED APPLICATION [0001] This application claims priority to PCT Application entitled “Robust 1D Gesture Light Control Algorithm,” having serial number PCT/CN2007/003050, filed on Oct. 26, 2007, which is incorporated by reference in its entirety. FIELD OF THE INVENTION [0002] The invention relates to a lighting system comprising a lamp arranged to transform electricity into a light beam having properties such as intensity, colour, colour temperature, direction and beam cone angle, and a light control means arranged to adjust said light beam properties. BACKGROUND OF THE INVENTION [0003] Adjustment of a lamp's properties is well known to be achieved via a remote control (RC). A disadvantage of a remote control is the necessity of the presence of the remote control on the right location at a random moment. Also a lot of different remote controls are already present in the living room for TV, audio, VCR, CD/DVD player/recorder, etc. Further, the different buttons on a remote control can be confusing to the user. Finally, the costs of a remote control and the accompanying receiver are relatively high. [0004] Also control of electrical devices by the use of video cameras and movement detection software is known, wherein the user can control the electrical device by making gestures in front of the camera. Such systems require heavy duty processing power, have a relatively long response time, and are relatively expensive. [0005] WO 2006/056814 describes a lighting system comprising a lamp and a control means comprising an infrared transmitter, an infrared receiver and a lens arrangement. The control means measure the intensity of the reflected infrared light, and changes the lamp brightness in reaction thereto. In this manner the lamp can be switched on and off, and can be dimmed by hand movements in the infrared beam. Such an arrangement is however relatively expensive and inaccurate, as the intensity of the reflected infrared signal heavily depends on the kind of object that is moved in the beam. [0006] It is a goal of the invention to provide an improved, cheap, reliable and easy-to-use control system for lighting. A further goal of the invention is to provide a lighting system that is safe and comfortable for its users and their environment. SUMMARY OF THE INVENTION [0007] According to the invention the lighting system further comprises an ultrasonic transmitter arranged to transmit ultrasonic signals, an ultrasonic receiver arranged to receive reflected ultrasonic signals, and a processing means arranged to derive a time-of-flight signal representing the time differences between said transmitted and received ultrasonic signals and to send control signals, for instance binary code, to said light control means in dependence of said time-of-flight signal. Thereby a user of the system can adjust the lamp properties by moving an object, such as his hand, in the ultrasonic beam. [0008] The ultrasonic transmitter may for instance emit sound at a frequency of 40 kHz. Although alternatives to the use of ultrasonic transmitters/receivers, such as for instance infrared or radar transmitters/receivers would be capable of measuring the time-of-flight of the respective signals, ultrasound is in particular suitable for the present application, since the time-of-flight (where the typical distance is between 0.2 and 2 meter) can be measured in milliseconds rather than in nanoseconds, which allows for easy and accurate measurement with low cost processing equipment. The system of the invention can be produced at very low cost, since piezoelectric acoustic transducers are very cheap. [0009] GB-A-2 291 289 describes a lighting system comprising a control means for switching a lamp on and off and for dimming the lamp, wherein piezoelectric ultrasonic transmitters and receivers are used to detect the presence of an object in the vicinity of the lamp, and said control means is arranged to react to the presence of said object. This system does however not use time-of-flight measurements of the ultrasonic signal, and thereby is not able to react to movement of the object. [0010] The system of the invention is easy to control, with a simple user interface which does not require additional equipment such as a remote control. Other qualities of the system of the invention are its robustness, its independency from environmental conditions, its one-dimensional recognition of control movements, and its low processing power requirements. The further advantage of an ultrasound sensor is that it is less influenced by changing ambient light, temperature and humidity conditions. [0011] The processing means is preferably arranged to analyse the dynamic behaviour of said time-of-flight signals and to send control signals to said light control means in dependence of said dynamic behaviour. Thereby the user can make gestures in the ultrasonic beam that will be recognised by the processing means and translated into control signals. [0012] Said processing means is preferably arranged to stop sending control signals if said time-of-flight signal changed from dynamic behaviour to a value that has been substantially constant for a first predetermined period of time, said first predetermined period of time preferably being in the range of 0.5-2 s. By switching off the sending of control signals it is possible to prevent accidental adjustment of the lamp properties by a moving object. In order to turn the sending of control signals on, said processing means is further preferably arranged to determine and store a highest reference value, which reference value is determined as the value that has been present during most of a second predetermined longer period of time of for instance several minutes, and said processing means is then further arranged to start sending control signals if said time-of-flight signal changed from said highest reference value to a lower value that has been substantially constant for at least a shorter third predetermined period of time, said third predetermined period of time preferably being in the range of 0.5-2 s. [0013] In the preferred embodiment said lamp is a spotlight type lamp arranged to emit a light beam having a beam cone angle θ smaller than 45°, preferably smaller than 30°. Said beam cone angle of the transmitted ultrasonic signals is preferably smaller than 15°. To that end said ultrasonic transmitter may comprise a horn for reducing the beam cone angle of the transmitted ultrasonic signals. [0014] In the preferred embodiment said ultrasonic transmitter and receiver are arranged to transmit and receive ultrasonic signals in a direction extending within the light beam of the lamp. The light source of said lamp is preferably a plurality of LEDs, wherein said ultrasonic transmitter and receiver preferably extend substantially between said plurality of LEDs. [0015] Said ultrasonic transmitter and receiver, processing means, and/or light control means, preferably extend in the lamp housing, and said ultrasonic transmitter and receiver preferably are a combined ultrasonic transducer. Thereby a compact and easy to install lighting system is provided, that is intuitively controlled by moving one's hand in the centre of the light beam. The invention also relates to a single lamp unit comprising the entire lighting system as described above. [0016] According to a further aspect of the invention, in order to adjust the sound pressure of the ultrasonic transmitter to an acceptable, un-harmful and comfortable level for the users of the lighting system and their environment, said processing means is further arranged to perform a sound pressure level calibration step wherein the amplitude of the received reflected ultrasonic signal of the receiver is measured and wherein the amplitude of the transmitted ultrasonic signal of the transmitter is adjusted such that the amplitude of the received reflected signal approximates a predetermined threshold value. The amplitude of the received reflected ultrasonic signal in a certain situation depends on the transmitted amplitude, the distance-of-travel, the environmental absorption (e.g. absorption of ultrasound by air), and the diffraction by the reflecting reference surface (e.g. a fixed table, floor, etc.). In a certain situation for the period that the lamp is switched on it can be assumed that the absorption and diffraction are either constant if no object moves into the ultrasonic beam, or that the received amplitude will increase because the reflecting object is closer to the ultrasonic receiver, and therefore after calibration the transmitted amplitude can remain constant while it is more or less ensured that the received signal is always higher than the required threshold. In case however that after calibration the lighting system does (sometimes) not react to control gestures of the user, the user can be instructed to calibrate the system while holding the control object (f.i. his hand) at the farthest point he is expecting to put said object for controlling the system. [0017] The transmitted and received sound pressure levels are measured in dB, but can be represented by a voltage, for instance the voltage put on the ultrasonic transmitter or the voltage received from the ultrasonic receiver. The maximum permissible exposure to 40 kHz ultrasound for instance is set by various organisations around 100 dB. The invention aims however at much lower levels than this, and will adjust the pressure level to a minimum, yet optimum level. [0018] In order to further reduce the influence of the acoustic pressure on the users, the system is arranged to transmit said ultrasonic signals intermittently in short (preferably max. 100 ms) intervals. [0019] Said processing means is preferably arranged to perform said sound pressure level calibration step in a short period, for instance within the first few seconds, after the lamp is switched on. Further said processing means is preferably arranged to start deriving said time-of-flight signal and sending control signals after said sound pressure level calibration step. Furthermore preferably said processing means is arranged to repeatedly perform said sound pressure level calibration step while it is deriving said time-of-flight signals and is sending said control signals to said light control means. Thereby a dynamic calibration of the sound pressure level to the lowest level that is necessary to operate the system is achieved. [0020] In order to achieve the minimum necessary sound pressure level for the system to work properly, said processing means is preferably arranged to start said sound pressure level calibration step with a first calibration cycle wherein the ultrasonic transmitter is caused to send an ultrasonic pulse with a predetermined lowest amplitude and wherein the amplitude of the received reflected signal is measured, and to repeat said calibration cycle with a transmitted amplitude that is increased in each subsequent cycle with a predetermined value as often as necessary until the amplitude of the received reflected signal is equal to or higher than said predetermined threshold value. Said processing means is preferably arranged to cause a warning signal to be emitted by said lighting system, for instance a flickering of said lamp, if the amplitude of the received reflected signal is lower than said predetermined threshold value after a predetermined maximum number of calibration cycles. [0021] There are several issues related to the robustness and reliability of a gesture light control system based on ultrasound. Reflections, diffraction, interference, noise may disturb the received signal. Other issues like a moved reference surface, other moving objects, multiple objects should be dealt with. [0022] According to a further aspect of the invention, in order to provide a robust and reliable system, said processing means is further arranged to perform a reference calibration step, wherein the time-of-flight (TOF) is repeatedly measured a multitude of times, and wherein the processing means determines if the deviation of the majority of the measured time-of-flight values (TOFI) of said multitude of measurements is lower than a predetermined threshold (z), and wherein said processing means is arranged to calculate the average (TOFREF) of said measured time-of-flight values (TOFI) and store said average (TOFREF) in memory means as a reference time-of-flight value if said deviation is lower than said threshold (z). Said processing means is preferably arranged to generate an error signal if said deviation is not lower than said threshold (z). [0023] Preferably said processing means is arranged to store said reference time-of-flight value (TOFREF) in said memory means only if said reference time-of-flight value (TOFREF) is greater than a predetermined minimum value. Said processing means is preferably arranged to generate an error signal if said reference time-of-flight value (TOFREF) is not greater than said predetermined minimum value. [0024] Preferably said processing means is arranged not to store a reference time-of-flight value (TOFREF) in said memory means if during said reference calibration step no signal is received by said ultrasonic receiver during at least a predetermined number of time-of-flight measurements. Said processing means is preferably arranged to generate an error signal if during said reference calibration step no signal is received by said ultrasonic receiver during at least said predetermined number of time-of-flight measurements. [0025] According to a further aspect of the invention, in order to provide a robust and reliable system, said processing means is arranged to perform a wait-for-control-enablement cycle wherein said time-of-flight (TOF) is repeatedly measured at predetermined intervals and to compare said measured time-of-flight value (TOF) with a reference time-of-flight value (TOFREF) which is stored in memory during said wait-for-control cycle, and to repeat said measurement if said measured time-of-flight value (TOF) is equal to or larger than said reference time-of-flight value (TOFREF), said processing means is further arranged to determine if the measured time-of-flight value (TOF) is smaller than said reference time-of-flight value (TOFREF) and if the deviation between the measured time-of-flight value (TOFH) and the previous measured time-of-flight value (TOFH−1) is lower than a predetermined threshold (tx), and said processing means is arranged to send control signals to said light control means in dependence of time-of-flight signals derived after it is determined that the measured time-of-flight value (TOF) is smaller than said reference time-of-flight value (TOFREF) and that said deviation is lower than said threshold (tx) for a predetermined number of repeated measurements. [0026] Said predetermined interval is preferably substantially larger if it is determined that said measured time-of-flight value (TOF) is equal to or larger than said reference time-of-flight value (TOFREF), than if it is determined that said measured time-of-flight value (TOF) is smaller than said reference time-of-flight value (TOFREF). [0027] Preferably said processing means is arranged to calculate the average of said measured time-of-flight values (TOF) and to store said average (TOFH) in memory means, and the processing means is arranged to send control signals to said light control means in dependence on the positive or negative difference between the measured time-of-flight (TOF) and said average time-of-flight (TOFH) after it is determined that said deviation is lower than said threshold (tx) for a predetermined number of repeated measurements. [0028] Preferably said processing means is further arranged to clip the difference of the measured time-of-flight value (TOF) to a maximum allowed positive or negative difference between the measured time-of-flight (TOF) and said average time-of-flight (TOFH) for the purpose of determining the control signals to be sent to the light control means. [0029] Preferably said processing means is further arranged to calculate said maximum allowed positive and negative difference such that the negative difference is smaller than said average time-of-flight (TOFH), and that the positive difference is smaller than the difference between said reference time-of-flight (TOFREF) and said average time-of-flight (TOFH). [0030] Preferably said processing means is further arranged to adapt the determination of the control signals to be sent to the light control means such, that the full range of control signal can be achieved within the calculated range of the maximum allowed positive and negative difference. [0031] According to a further aspect of the invention, in order to be able to adjust different light beam properties, said processing means and said light control means are further arranged to change from adjustment of one of said light beam properties to adjustment of another one of said light beam properties, if a predetermined behaviour in said time-of-flight signal is determined. [0032] In a preferred embodiment said behaviour is a series of subsequently measured time-of-flight values that is substantially constant during a predetermined period. [0033] In a further preferred embodiment said behaviour is a predetermined number of alternations of high and low measured time-of-flight values. [0034] In a still further preferred embodiment said behaviour is a predetermined number of alternations of the presence and absence of measured time-of-flight values. [0035] In a remote controlled lighting system it is desirable to provide feedback about the status and working of the system to the user in an efficient and low-cost manner. [0036] The invention therefore further relates to a lighting system comprising a lamp arranged to transform electricity into a light beam having properties such as intensity, colour, colour temperature, direction and beam cone angle; a light control means arranged to adjust said light beam properties; a processing means arranged to send control signals to said light control means; a user control interface arranged to transform user control input into electronic input signals and to send those electronic input signals to said processing means; wherein said processing means is arranged to send a user feedback signal to said light control means such that said lamp properties either alternate in time or are different in adjacent locations, such that a user can recognize said alternating or adjacent different light properties as a feed back signal. [0037] Preferably said processing means is arranged to send said user feedback signal to said light control means for a short period of time, for instance 0.2-5 seconds, and to send subsequently a signal to said light control means such that said lamp properties return back to the previous state or are set to a predefined steady state such as the switched off state. [0038] In a preferred embodiment said feedback signal is such that the lamp intensity is visibly changed at least twice within said short period of time. [0039] In a further preferred embodiment said feedback signal is such that the colour temperature is visibly changed at least twice within said short period of time. [0040] In a still further preferred embodiments said lamp comprises an array of LEDs, wherein said light control means is arranged to individually power said LEDs in said LED array, and wherein said feedback signal is such that a visible sign such as a letter or an icon is formed in said array during said short period of time. Preferably said lamp comprises a lens to project said LED array on a reference surface. Said lens is preferably adjustably mounted in said lamp such that it is adjustable in dependence of the measured distance between the lamp and the reference surface. [0041] In the preferred embodiment said user control interface comprises an ultrasonic transmitter arranged to transmit ultrasonic signals; an ultrasonic receiver arranged to receive reflected ultrasonic signals; wherein said processing means is arranged to derive a time-of-flight signal representing the time differences between said transmitted and received ultrasonic signals and to send control signals to said light control means in dependence of said time-of-flight signal. Said ultrasonic transmitter and/or receiver is preferably built-in in the centre of the lens. [0042] It is desirable that the ultrasound controlled lighting system is easy to produce in mass quantities, with low cost components, and has small dimensions so that it can be built-in in even in a small lamp. [0043] The invention therefore further relates to a lighting system comprising a lamp comprising an array of LEDs arranged to transform electricity into a light beam having properties such as intensity, colour, colour temperature; a light control means comprising a LED driver and a pulse width modulator arranged to adjust said light beam properties; a DA-converter, an ultrasound driver and an ultrasonic transmitter arranged to convert a digital transmit signal into the transmission of an ultrasonic pulse; an ultrasonic receiver and an amplifier arranged to receive reflected ultrasonic signals and transform said ultrasonic signal in a voltage, and a comparator arranged to generate a digital receive signal if said voltage is greater than a predetermined threshold; a processing means arranged to derive a time-of-flight signal representing the time differences between said digital transmit and receive signals and to send control signals to said light control means in dependence of said time-of-flight signal, wherein said processing means, said pulse width modulator, said DA-converter and said comparator are integrated in a single microcontroller chip. [0044] Said microcontroller chip is preferably chosen from the single-chip 8-bit 8051/80C51 microcontroller family, preferably comprising small sized RAM and ROM, preferably smaller than 4 kB ROM and smaller than 512 B RAM. [0045] Preferably said ultrasonic transmitter and said ultrasonic receiver are integrated in a piezoelectric ultrasound transducer. [0046] Preferably said transmitting ultrasound driver and said receiving ultrasound amplifier are integrated in a pre-processing circuit. Said pre-processing circuit preferably further comprises a second order filter for filtering out low frequent signals from said received signal. BRIEF DESCRIPTION OF THE DRAWINGS [0047] The invention will be further explained by means of a preferred embodiment as shown in the accompanying drawings, wherein: [0048] FIG. 1 is a graph showing the principle of time-of-flight measurement with an ultrasonic transceiver; [0049] FIG. 2 is a schematic perspective view of the lamp and its control mechanism; [0050] FIG. 3 is a combined drawing showing stills of hand movements in the system of FIG. 2 and a graph showing the time-of-flight signal against time, and various stages of lamp property control caused by said hand movements; [0051] FIG. 4 is a schematic perspective view of the lamp of FIG. 2 ; [0052] FIG. 5 is a schematic top view of an average hand; [0053] FIG. 6 is a three-dimensional graph showing beam radius against beam angle and vertical distance; [0054] FIG. 7 shows schematically the movement of a hand in and out of the beam and the related graph of the time-of-flight against time; [0055] FIG. 8 is a schematic cross-sectional view of an ultrasonic transducer and a horn; [0056] FIG. 9 is a flow chart showing the calibration process of the lamp system; [0057] FIG. 10 is a combined drawing showing graphs of the voltage of the transmitted ultrasound pulse signals, the voltage of the received reflected signals and the status of the sound pressure level calibration in time; [0058] FIGS. 11A-11C shows schematically the movement of a hand in and out of the beam; [0059] FIG. 12 shows schematically the movement of a vase in the beam and the related graph of the time-of-flight against time and the various phases of control; [0060] FIGS. 13-18 and 20 - 21 show flow charts of various control algorithms; [0061] FIG. 19 schematically shows the determination of the control range; [0062] FIG. 22 schematically shows the control mechanism of different light properties in time; [0063] FIGS. 23-28 schematically show the control mechanism of different light properties in various stages; [0064] FIGS. 29 and 30 show schematically the movement of a hand in the beam and the related graph of the time-of-flight against time; [0065] FIG. 31 schematically shows a LED array lamp showing a message; [0066] FIG. 32 schematically shows a LED array lamp projecting a message on a reference surface; [0067] FIGS. 33 and 34 schematically show an electronic hardware implementation of the invention; and [0068] FIG. 35 is a perspective view of a lamp according to the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0069] The lamp 1 as shown in FIG. 2 comprises a plurality of LEDs and an ultrasonic transceiver built-in in the centre of said plurality of LEDs. Also a processing means for translating the signals of the transceiver into control signals, and control means to adjust the light properties are built-in. [0070] If the ultrasonic transceiver is switched on it will send an acoustic signal. If an object is present the acoustic signal will be reflected at the object and will be received by the ultrasonic transceiver inside the lamp. The time difference, called the time-of-flight, between sending and receiving the acoustic signal will be measured. If the distance between the object and the lamp 1 is changed another time-of-flight value will be measured. The detected movement of the object is a one-dimensional movement (the object must stay in the ultrasound beam cone). The change in time-of-flight will be translated into a change in a digital control signal. This control signal will control the properties of the light beam, like colour, intensity or colour temperature, etc. [0071] The object may be the hand 2 of a user. Thus a one-dimensional movement of the hand 2 , like up/down or left/right direction (depending on lamp position, horizontal or vertical) can control the light beam properties. [0072] In commercially available pulse echo distance measurement units of the transmitter-reflector-receiver type (TRR), the most common task is to measure the distance to the closest reflecting object. The measured time is the representative of travelling twice the distance. The returned signal follows essentially the same path back to a receiver located close to the transmitter. Transmitting and receiving transducers are located in the same device. The receiver amplifier sends these reflected signals (echoes) to the micro-controller which times them to determine how far away the object is, by using the speed of sound in air. [0073] The time-of-flight of acoustic signals is commonly used as a distance measurement method. A time-of-flight measurement, as illustrated in FIG. 1 is formed by subtracting the time-of-transmission (T in FIG. 1 ) of a signal from the measured time-of-receipt (R in FIG. 1 ). This time distance information will be transferred into a binary code in the microprocessor to control the lamp properties. [0074] In FIG. 2 a hand 2 is the obstacle/object and a table 3 , floor or ceiling is the reference. The ultrasonic transducer sends an ultrasonic wave in the form of a beam cone 4 . If the distance y from the transducer to the reference is 1.5 m, the total travel distance for the ultra-sound beam 4 is 2*y=3 m. The time-of-flight then is 8.7 ms (at an ambient temperature of 25° C.). If the distance x from the transducer to the hand is 0.5 m, the time-of-flight is 2.9 ms. If the required accuracy of control steps of the hand movement is 2 cm (time-of-flight steps of 0.12 ms), and the range of control is for instance 64 cm, there are 32 control steps, which allows for 5-bit control. [0075] The control signal as shown in FIG. 3 is made by the movement of the hand 2 in a one-dimensional vertical direction in the ultrasonic beam 4 . At T 1 =1 s the hand 2 is outside the beam, the reference value is measured, and lamp control is disabled (stage A). At T 2 =2 s the hand 2 moves into the beam 4 and is held there for more than 1 second until at T 3 =3 s lamp control is enabled by the microcontroller (stage B). Then the hand 2 moves up between T 3 =3 s and T 5 =5 s, whereby for instance the intensity of the lamp 1 is increased by the microprocessor (stage C). At T 6 =6 s the hand is withdrawn from the beam 4 so that the reference value is measured, and lamp control is disabled thereby (stage D). An accidental movement of the hand 2 in the ultrasonic beam 4 as shown at T 7 =7 s does therefore not result in an accidental adjustment of the lamp properties (stage E). Hence, the lamp control is activated by holding an object in the ultrasonic beam 4 for more than 1 second. [0076] The ultrasonic beam cone angle is important to provide reliable hand control. In FIG. 4 the beam radius at the reference position is r. The beam radius rh at the hand position must be high enough to have optimum control by hand. During control of a lamp property the average beam radius should be equal to approximately half the length of the average hand shape as shown in FIG. 5 . If the total control range is around X/2 (for a lamp/table application), the ultrasound beam angle at the minimum beam radius during control of the lamp property will be around Lh/2. For example: if Lh=150 mm and X=1.5 m, the ultrasound beam angle θ should be 11°. The relationship between the vertical distance X and the beam angle as function of the beam radius is shown in FIG. 6 . Lamp control will be possible if the hand 2 is in the narrow ultrasound cone 4 as shown in FIG. 7 . Reduction of a wide ultrasound beam 4 and an increase of sound pressure level (SPL) of an ultrasonic transducer 5 may be achieved by a horn 6 as shown in FIG. 8 . [0077] FIG. 9 shows the calibration process of the sound pressure level (SPL) generated by the ultrasound transducer. In step A, when the lamp is switched on, the value for the representative of the sound pressure level amplitude (SPLampI T ) as transmitted by the transducer is zero and the value of the sound pressure level status (SPL OK) is zero. Said representative for SPLampI T may for instance be expressed in a voltage which is put on the transducer. [0078] In step B the first calibration cycle is started by the processing means, by increasing the transmitted sound pressure level amplitude value by incremental increase value (gain) G. In step B the transducer sends an ultrasound pulse based on said SPLampI T value. In steps D and E the processor monitors during a maximum period of 20 ms if a signal is received that is greater than a predetermined threshold value. If no such signal is received after 20 ms, in step F a period of 100 ms is waited, and the loop is repeated as from step B. [0079] If in step D it is determined that a signal SPLampI R is received that is greater than a predetermined threshold value, at least two extra smaller increases of SPLampI T may be made in order to ensure that the emitted amplitude has enough margin to compensate for instance for temperature changes. To that end, if in step G it is determined that SPL OK is not greater than 1, then in step H SPL OK is increased by 1, the value for the incremental increase is reduced to half the previous value, and after waiting 100 ms in step F the loop is repeated as from step B. [0080] After these steps the final value for SPLampI T is established and stored in memory in step I. This value is then used during the remaining period that the lamp is on, i.e. the voltage represented by said value is put on the transducer during the light control process of the lamp as described above. [0081] The above calibration process of the SPL does not necessarily take place on a fixed reference surface such as a table. It can also be applied while the user is holding his hand in the ultrasonic beam, preferably at the lowest point of control operation. Thereby the SPL can be set at a lower level than for instance would be the case if the fixed reference surface would be a floor. It is even possible to combine the SPL calibration process with the control movement of the hand, and dynamically calibrate the sound pressure level while the hand is moving in the ultrasonic beam. [0082] The process of increasing the voltage put on the transducer during the transmission of ultrasonic pulses and measuring the voltage of the received reflected signals from the transducer, and increasing the SPL OK status until the threshold is exceeded is shown in FIG. 10 . [0083] There are two important issues with respect to robustness of gesture light control based on ultrasound: acoustic issues like reflections, diffraction, fatal interference, extra noise adds to receiver, and user interface issues like unstable objects (as shown in FIG. 11A-11C ), changed (reference) objects (as shown in FIG. 12 ), and different objects at the same time, etcetera. [0084] In FIG. 11A a hand 2 is shown, which accidentally moves horizontally through the ultrasonic beam 4 from T 1 to T 3 . In FIG. 11B a hand 2 is shown, which accidentally moves vertically through the ultrasonic beam 4 from T 1 to T 3 . In FIG. 11C a hand 2 is shown which moves into the ultrasonic beam 4 from T 1 to T 2 and is held stably in said beam until T 3 . It is desirable that the accidental movements as shown in FIGS. 11A and 11B do not incur any light control actions. The action as shown in FIG. 11C however is proposed to be a user command that enables light control thereafter, as explained above with reference to FIG. 3 . [0085] In FIG. 12 a vase 7 is shown, which is put on the reference surface 3 (for instance a table) between T 1 and T 2 . Thereby the measured time-of-flight is shortened. On T 1 lamp control is disabled (stage A), and the shortened time-of-flight will result in enablement of the lamp control (stage B), as explained above with reference to FIG. 3 . [0086] If however the vase 7 , is in the beam 4 for more than a predetermined period, for instance 1.5 seconds or longer, then it is assumed that a new reference object is placed in the beam (stage C). The measured value is then stored as the new reference value and control is disabled (stage D). [0087] In FIG. 13 a basic algorithm for gesture light control is shown. If we the lamp is switched on (step A) and hardware is initialised (step B) the sound pressure level will be calibrated (step C) as described above with reference to FIG. 9 . The ultrasonic transceiver will be sent an acoustic signal to check if a (reference) object is present and to regulate the sound pressure of the acoustic echo signal to a minimum. If no signal is received after a predetermined period (step D), an error signal is generated and presented to the user (step E). [0088] Then a reference calibration (step F) will be performed at a fixed obstacle like a table, a floor, etcetera and is based on the first received echo signal after sending a pulse to the transmitter. Other received echo signals shifted in time (compared with the first received echo) are signals based on reflection (as shown in FIG. 1 ). These signals are eliminated. [0089] The reference calibration algorithm (step F) is further explained with reference to FIG. 14 . A pulse is sent (step G) and the time-of-flight from the source to the reference surface and back to the source is measured (step H) and stored as TOF I (step J). If no signal is received after a predetermined time-out period (for instance 3 seconds) (step K) after more than two attempts (step L), an error signal is generated and presented to the user (step M). Reproducibility of this measurement is checked by repeating the measurement for I=0 to I=19. A check is performed if the stored values for TOF I (apart from the two most extreme values) are within a predetermined threshold z (step O), otherwise the reference calibration is started again. Then the average reference value TOF REF is calculated (step P) and is stored as representative of the maximum allowable distance (step Q), but only if said TOF REF is larger then a predetermined minimum, otherwise an error signal is generated and presented to the user (step R). In this example said minimum is 32 times a predetermined minimum increment, so that at least 32 incremental distances of a hand movement can be measured and translated into control instructions. During gesture control no movement beyond the maximum distance represented by TOF REF is expected nor tolerated. The reference distance will also determine the control range. [0090] After the reference calibration (step F) the system is set into a “wait-for-control-enable” state (step S), as shown in FIG. 15 . The sample frequency is reduced to 4 Hz (250 ms) (step V). The system will wait for an obstacle/object (e.g. a hand), by measuring TOF H (step T, shown in more detail in FIG. 16 ; Time_out=100 ms) and comparing said TOF H with the reference value (step U). As long as TOF H is greater than or equal to the reference value TOF REF it is assumed that no object is present in the beam and the system will repeat this cycle at the sample frequency. [0091] If TOF H is smaller than the reference value TOF REF twenty measurements (for H=0 to 19) during 1 second are performed to check if the object is stable, by checking if the difference between TOF H and the previous measurement TOF H−1 is smaller than a predetermined threshold tx (for instance a value representing a distance of 2 cm) (step V). If this is the case the average of the measured TOF-s, TOFH (step W) is stored and the algorithm continues to the control enable step (step X) in FIG. 13 . During the control enable cycle the system checks if the object (hand) is still present in the beam (step X 3 in FIGS. 13 and 17 ) and if the object is making control gestures, i.e. by moving (step X 4 in FIGS. 13 and 17 ), as explained in more detail with reference to FIG. 17 below. Through the above-described algorithm the system will not react on short (<1 second) disturbances of the ultrasound beam cone during the wait-for-control-enable cycle. A continuous check if echo signals are received will be carried out at the reduced sample frequency. [0092] By the proposed algorithms the control of light will be only possible when the hand movement fulfils a certain profile, as exemplified above with reference to FIG. 3 . Control is disabled when the hand is moved outside the ultrasound beam cone (step D in FIG. 3 ). Control is also disabled when the reference object is changed, as explained above with reference to FIG. 12 . [0093] Now with reference to FIGS. 17 and 18 (wherein C and FC start with value 0) the enable-control algorithm (step X) is further explained. In order to give feedback to the user with respect to the fact that control is enabled, a visual signal is given, for example in this embodiment a green LED (G-LED) will be switched on (step X 1 ). The sample frequency is increased to 40 Hz. [0094] Based on the determined TOF the control range will be automatically determined (step X 2 ), as illustrated in FIGS. 19 and 20 . Preferably the total number of steps Ns tot is chosen such that the sensitivity of the system, i.e. the length of a control step, is approximately 2 cm, which corresponds to a TOF of 0.116 ms (2*0.02 m/345 m/s). A preferred number of control steps of 32 is proposed, so that the control range of the hand is 64 cm, wherein the initial position of the hand is the centre of said range. However if the hand is closer to the source or the reference surface than 32 cm (minus a safety margin, reflected by TOFBS and TOFBR) obviously the control range cannot be 32 cm on either side of the hand, and the control range is shifted, for instance by locating the upper or lower limit of the control range (RangeMin or RangeMax) on the respective safety margin borders (TOFBR or TOFBS). [0095] The time-of-flight (TOF C ) between the source and the hand is determined. Continuous checks are made to determine if the hand is still in the beam (step X 3 ) and if the hand is moving (step X 4 ). If the hand is not in the ultrasound beam anymore for a predetermined time, control will be disabled. If the hand is in the beam, but not moving for at least one second, it is checked if prior thereto light properties have been controlled (FC>0). If this is the case, the FC is reset to 0 and control is disabled. If this is not the case, the control mode is switched to controlling a different light property, indicated by FC being raised by 1, and the algorithm returns to TOF C determination loop. [0096] If it is determined that the hand is moving (step X 4 ), and then it is checked if the TOF C is within the calculated range (step X 5 ). If TOF C is outside said range clipping takes place (step X 6 ), for instance by replacing TOF C with the nearest maximum value, as illustrated in FIG. 21 . The direction (step X 7 ) and the number of steps Ns act (step X 8 ) is calculated, which is used to translate the physical hand position into a digital position value for control purposes. [0097] Ns act is calculated by dividing the difference in the measured TOF (TOF C −TOF C−1 ) by TOF. These values are translated to a drive signal sent to the LED drivers to control the light properties. The current value of FC determines which one of the light properties is controlled (step X 9 ). In this example there are only two properties to be controlled: “basic control” and “fine control”, but this can be easily extended. This control loop for controlling a light property is repeated until control is switched off, or until FC is raised so that a different light property is controlled. [0098] Three different methods are proposed as examples for selecting the light properties to be controlled, based on a menu structure. In the first method the selection of the basic light controls will be based on the freezing of the object (i.e. hand 2 ) during for instance 1 second. The second method of selection of the basic controls is based on rotation of the hand. The third method of selection in menu control for basic light controls is based on the hand crossing the ultrasound beam in horizontal direction (assuming that the ultrasound beam extends in vertical direction). [0099] With these methods the basic light controls can be selected in a sequential manner, as illustrated in FIG. 22 . This means that if a user first selects a light colour (from 1 s to 1.8 s), the control selection is moved on towards control of the colour temperature of the chosen colour 1 second later (at 2.8 s). Control of colour temperature is then also achieved by hand movement (from 2.8 s). The control range is chosen the same as used for the previous basic control. [0100] FIGS. 23-28 shows as an example the different steps in a menu for three basic LED light controls. In FIG. 23 the colour is controlled by up-and-down movement of hand 2 . In FIG. 24 the hand 2 is frozen at specific desired colour for 1 second, so that said specific colour is chosen, and control selection is switched to colour temperature control in FIG. 25 . In FIG. 26 the hand 2 is frozen at a specific desired colour temperature again for 1 second, so that said specific colour temperature is chosen, and control selection is switched to intensity in FIG. 27 . In FIG. 28 hand 2 is frozen at a specific desired light intensity, so that said specific light intensity is chosen, and control is switched off. [0101] Switching from one basic control to another one can also be achieved by making a hand rotation. Therefore a certain angle between hand and ultrasonic beam has to be made (see FIG. 29 ). If the angle between hand and ultrasound bean cone is 90 degrees the maximum echo signal will be received by the ultrasound transceiver. If the hand makes an angle of 45 degrees with the ultrasound beam cone (almost) no echo signal will be received by the transceiver, because the echo signal will be reflected by the hand to another position. A certain unique profile can be chosen for selecting one of the basic controls in a menu, for example as shown in FIG. 29 . [0102] With this method the user can switch from one basic control to another one without the need to control each basic control. Stepping through the menu is done by another type of [0103] Selection of a basic light control can also be achieved by (horizontal) hand movements crossing the ultrasound beam cone, as illustrated in FIG. 30 . The time-of-flight is measured with a high sample rate, and an alternating TOF signal (low-high-low, etcetera) is recognized as a unique profile, which can be chosen for selecting the basic controls in a menu. [0104] In a light remote control system, before, during or after the user inputs light control instructions feedback or messages will be given to said user, comparable to TV applications where feedback is given via the display to the user during control of the basic functions like contrast, brightness, saturation, etcetera. For example if the light system does not receive the control signal, or the signal is too weak, a certain error messages to the user is desirable. [0105] Depending of the used light control application like remote control, ultrasound or video based gesture light control, different feedback mechanisms are proposed. [0106] In a menu controlled system changes have to be made visible for the user. Also when control is enabled feedback has to be given. If an error occurs also feedback has to be given to the user. Also different kinds of error messages can be given to the user or to a service environment for fast analyses and repair of the error. [0107] The first proposed method for feedback to the user is messaging by light pulses, or flickering of light. [0108] Eyes are very sensitive for light flicker until frequencies around 60 Hz. Flicker can be made by switching the light off and on again very fast. A alternative method to create light flicker is reducing light intensity for a very short moment in time and change it back to the original light intensity. [0109] The second proposed method for feedback to the user is messaging by light colour changes or colour temperature changes. Different colours or colour temperature could give different messages to end-user. Also a combination of the first two methods can communicate extra information to the user. [0110] The third proposed method is to make text feedback using a LED array lamp. By placing the LEDs in an array as shown in FIG. 31 , array text messages can be formed. Also icons can be formed. FIG. 31 shows an example of a message text “E 2 ”, which could be a certain error message. In this manner the LED lamp is used as a display to send different text messages to the user or service department during an error situation. [0111] As shown in FIG. 32 , the text of the LED array can also be projected by a lens 8 on an object surface (reference 3 ) like a table, a wall or floor. In an ultrasound based gesture light control system as described above the distance between the lens 8 and the object (the focal length f) by the TOF measurement of the ultrasound sensor 5 (here shown built in the lens 8 ) can be used. With this information the focal length can be adjusted as function of the distance with the object (automatic focus). For example a stepper motor can perform the adjustment of the focal length. The text of the lamp array has to be mirrored if a lens is used. [0112] In order to reduce the costs of the lamp to a minimum and to have the possibility to control all possible lighting parameters like colour, intensity, etcetera, the electronic circuit needed for carrying out the control functions is integrated in the lamp. The microprocessor used for gesture control is also integrated in the LED control microprocessor to reduce the cost even more. The integration of the ultrasound sensor in the lamp makes low cost, high volume production possible. [0113] With reference to FIG. 33 , as explained above the micro-controller sends a pulse to the ultrasound transmitter of the ultrasound transceiver 5 . A digital pulse signal is generated by the control part 13 A of a micro-controller 13 , and converted by DA-converter 17 in said micro-controller 13 into an electric pulse. This pulse will be amplified by the amplifier 18 in the pre-processor 10 (shown in more detail in FIG. 34 ) to a value that can be used by the ultrasound transmitter part of the ultrasound transceiver 5 . Then the piezo-electric ultrasound transceiver 5 sends an acoustic signal (for instance at a frequency of 40 kHz). An object will reflect this acoustic signal. The pre-processor 10 will receive the reflected signal via the ultrasound transducer 5 . In order to reduce the influence of outside disturbances the signal is filtered by a 2nd order High-Pass filter 11 of for instance 20 kHz (=fc). After filtering the signal is amplified by amplifier 12 in the pre-processor 10 . [0114] Microcontroller 13 comprises a comparator 14 , which creates a digital pulse signal from the electric signal received from the pre-processor 10 , which can be processed by the micro-controller 13 . [0115] The micro-controller 13 further comprises a LED driver part 13 B, with a modulator 20 , which is connected to the LED driver 19 , and part of the ROM 15 and the RAM 16 , which is shared, with the control part 13 A of the micro-controller. [0116] Such a micro-controller 13 , arranged to drive a LED, is well known in the art, but is further programmed to perform the control functions as described above. The micro-controller can be a simple processor, for instance of the 8051-family. The size of the ROM 15 can be as low as 2 kB and the size of the RAM 16 can be as low as 256 bytes. [0117] FIG. 35 shows a lamp according to the invention comprising a housing with a standard incandescent lamp type fitting, ten LEDs 21 arranged in a circle, a transducer 5 in a horn 6 . All the electronic components like the micro-controller 13 , pre-processor 10 and LED driver 19 are built-in in the housing 23 . Thereby a very compact lighting system is obtained, which requires no further external accessories to be operated and controlled. [0118] Although the invention is described herein by way of preferred embodiments as example, the man skilled in the art will appreciate that many modifications and variations are possible within the scope of the invention.

A lighting system comprising a lamp arranged to transform electricity into a light beam having different properties; a light control means arranged to adjust said light beam properties; an ultrasonic transmitter arranged to transmit ultrasonic signals; an ultrasonic receiver arranged to receive reflected ultrasonic signals; and a processing means arranged to derive a time-of-flight signal representing the time differences between said transmitted and received ultrasonic signals and to send control signals to said light control means in dependence of said time-of-flight signal. The processing means performs a reference calibration step: the time-of-flight is repeatedly measured a multitude of times, and calculates the average of said measured time-of-flight values and stores the average in memory means as a reference time-of-flight value if said deviation of the majority of the measured time-of-flight values of said multitude of measurements is lower than a predetermined threshold.

This application is a Continuation of application Ser. No. 09/071,674, filed on May 1, 1998 now U.S. Pat. No. 6,189,030, which application(s) are incorporated herein by reference. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is generally related to the control of network information server systems supporting World Wide Web based data pages and, in particular, to a server system and process for efficiently redirecting external server hyper-link references for purposes of controlling, moderating, and accounting for such references. 2. Description of the Related Art The recent substantial growth and use of the internationally connected network generally known as the Internet has largely been due to widespread support of the hypertext transfer protocol (HTTP). This protocol permits client systems connected through Internet Service Providers (ISPs) to access independent and geographically scattered server systems also connected to the Internet. Client side browsers, such as Netscape Mozilla® and Navigator® (Netscape Communications Corp.), Microsoft Internet Explorer® and NCSA Mosaic™, provide efficient graphical user interface based client applications that. implement the client side portion of the HTTP protocol. Server side application programs, generically referred to as HTTPd servers, implement the server side portion of the HTTP protocol. HTTP server applications are available both commercially, from companies such as Netscape, and as copyrighted freeware available in source code form from NCSA. The distributed system of communication and information transfer made possible by the HTTP protocol is commonly known as the World Wide Web (WWW or W3) or as simply “the Web.” From a client side user interface perspective, a system of uniform resource locators (URLs) is used to direct the operation of a web browser in establishing atomic transactional communication sessions with designated web server computer systems. In general, each URL is of the basic form: http://<server_name>.<sub-domain.top_level-domain>/<path> The server_name is typically “www” and the sub_domain.top-level_domain is a standard Internet domain reference. The path is an optional additional URL qualifier. Specification by user selection of a URL on the client side results in a transaction being established in which the client sends the server an HTTP message referencing a default or explicitly named data file constructed in accordance with the hypertext mark up language (HTML). This data file or web page is returned in one or more response phase HTTP messages by the server, generally for display by the client browser. Additional embedded image references may be identified in the returned web page resulting in the client browser initiating subsequent HTML transactions to retrieve typically embedded graphics files. A fully reconstructed web page image is then presented by the browser through the browser's graphical user interface. Due to the completely distributed client/server architecture of the Web, as made possible by the URL system further supported by the existing Internet name resolution services and routing conventions, HTTP servers can be independently established with little difficulty. Consequently, the Web has no centrally or even regionally enforced organization other than loosely by name of the top level domain. Searching for information or other resources provided by individual HTTP servers is therefore problematic almost by definition. Because of the time, cost and complexity of assembling comprehensive, yet efficiently searchable databases of web information and resources, commercial Internet Business Services (IBS) have been established to provide typically fee based or advertising revenue supported search engine services that operate against compilations of the information and resources available via the Web correlated to source URLs. Access to such search engines is usually provided through server local web pages served by the Internet Business Services. The results of a search are served in the form of local web pages with appropriate embedded remote or hyper-linked URLs dynamically constructed by the server of the Internet Business Service. Because of the opportunity presented by the likely repeated client access and retrieval of search engine and search result web pages, providers of other Internet based services have begun to actively place advertisements on these web pages. As is typical in advertising mediums, the frequency of display of an advertisement generally defines the compensation paid to the advertisement publisher. Thus, the number of times that an advertisement is simply transferred to a client browser provides an indication of how effectively the advertisement is being published. A more direct measure of the effectiveness of a particular advertisement on a particular web page is the number of times a client web browser chooses to actively pursue the URL represented by the advertisement. Thus, there is a need to be able to track, information obtainable from a client browser when a hyper-linked advertiser's URL is selected. The difficulty in obtaining direct reference information arises from the fact that a web page with an embedded advertisement and corresponding remote URL is served in its entirety to the client browser upon first reference to the web page. The selection of a particular advertiser's URL is then by definition performed through an independent transaction directed to the HTTPd server associated with the advertiser. Since the advertiser publishing HTTPd server is not part of this subsequent transaction, the publishing server is conventionally incapable of tracking client browser hyper-links actually executed to an advertiser's URL or any other URLs embedded in a web page previously served to the client browser. Simple web page access counters are relatively well known and used throughout the Web. These access counters are based on a common gateway interface (CGI) facility supported by modern HTTPd server systems. The CGI facility permits generally small programs, at least typically in terms of function, to be executed by a server in response to a client URL request. That is, the HTML web page definition provides for the embedding of a specific HTML reference that will specify execution of a server side CGI program as part of the process of the web browser reconstructing an image of a served web page. Such a HTML reference is typically of the form: <img src=“http://www.target.com/cgi-bin/count.cgi”> Thus, a counter value incremented with each discrete execution of the CGI program (count.cgi) dynamically provides part of the displayable image of the reconstructed web page. The time, remote client requester, client domain, client browser type and other information that may be known through the operation of the HTTP protocol may be logged as part of the CGI program's function. Consequently, a reasonable manner of accounting and auditing for certain web page accesses exists. Access counters, however, fundamentally log only server local web page accesses. The client browser to the CGI program is evaluated by the client in connection with the initial serving of the web page to the client browser. The initial serving of the web page to the client browser can be connected, but any subsequent selection of a URL that provides a hyper-link reference to an external server is not observed and therefore is not counted by a CGI program based access counter. Other limitations of access counters arise from the fact that the implementing CGI program is an independently loadable executable. The CGI program must be discretely loaded and executed by the server computer system in response to each URL reference to the CGI program. The repeated program loading and execution overhead, though potentially small for each individual invocation of the CGI program, can represent a significant if not substantial load to the sever computer system. The frequent execution of CGI programs is commonly associated with a degradation of the effective average access time of the HTTPd server in responding to client URL requests. Since an Internet Business Service providing access to a search engine logs millions of requests each day, even small reductions in the efficiency of serving web pages can seriously degrade the cost efficiency of the Internet Business Service. As of December, 1995, Infoseek Corporation, in particular, handles an average of five million retrievals a day. The execution overhead associated with CGI programs is often rather significant. Many CGI programs are implemented at least in part through the use of an interpreted language such as Perl or TCL. Consequently, a substantial processing overhead is involved in multiple mass storage transfers to load both the interpreter and CGI program scripts, to process the scripts through the execution of the interpreter, and then actually log whatever useful data is generated, typically to persistent mass storage. Finally, the interpreter and/or CGI program may have to be unloaded. In addition, external CGI programs present a significant problem in terms of maintenance, including initial and ongoing server configuration and control, and security in the context of a busy server system. Individual CGI programs will likely be needed for each independent web page in order to separately identify web page service counts. Alternatively, a CGI program can be made sufficiently complex to be able to distinguish the precise manner in which the program is called so as to identify a particular web page and log an appropriately distinctive access count. Maintenance of such CGI programs on a server system where large numbers of page accesses are being separately counted is non trivial. Further, the existence of external programs, particularly of scripts that are interpreted dynamically, represents a potential security problem. In particular, the access and execute permissions of interpreted scripts must be carefully managed and monitored to prevent any unauthorized script from being executed that could, in turn, compromise the integrity of the data being collected if not the fundamental integrity of the server computer system itself. Consequently, known access counters provide no solution directly in full or in part to the need to account or audit URL references to external servers based on hyper-links from previously served web pages. The HTTP protocol itself provides for a basic server based system of URL redirection for servers and clients supporting the 1.5 or later versions of the HTTP protocol. A configuration file associated with an HTTP server (typically srm.conf) can specify a redirect directive that effectively maps a server local directory URL reference to an external URL reference through the use of a configuration directive of the form: Redirect/dir1 http://newserver.widget.com/dir1 When a Version 1.5 or later HTTP server receives a URL reference to a focal directory (/dir1) that is specified as above for redirection, a redirect message is returned to the client browser including a new location in the form of an URL (http://newserver.widget.com/dir1). This redirect URL is then used by the client browser as the basis for a conventional client URL request. This existing server based redirection function is insufficient to support external server access tracking since, in its usual form, the redirection is of the entire directory hierarchy that shares a common redirected base directory. Even in the most restricted form, the redirection is performed on a per directory reference basis. Thus, every access to the directory, independent of the particular web page or graphics image or CGI program that is the specific object of an access request is nonetheless discretely redirected without distinction. Any potential use of the existing server redirect function is therefore exceedingly constrained if not practically prohibited by the HTTP protocol defined operation of the redirect directive. Furthermore, the redirect directive capability of the HTTP protocol server does not provide for the execution of a CGI program or other executable coincident with the performance of the redirection thereby essentially precluding any action to capture information related to the redirect URL request. In addition, the complexity of the resource configuration file necessary to specify redirection down to a per directory configuration again raises significant configuration, maintenance and, to a lesser degree, security issues. Thus, server redirection does not possess even the basic capabilities necessary to support external URL hyper-link reference auditing or accounting. Finally, a form of redirection might be accomplished though the utilization of a relatively complex CGI program. Such a redirection CGI program would likely need to perform some form of alternate resource identification as necessary to identify a redirection target URL. Assuming that a unique target URL can be identified, a redirection message can then be returned to a client from the CGI program through the HTTP server as necessary to provide a redirection URL to the client browser. Unfortunately, any such CGI program would embody all of the disadvantages associated with even the simplest access counter programs. Not only would problems of execution load and latency, as well as configuration, maintenance and security remain, but such an approach to providing redirection is inherently vulnerable to access spoofing. Access spoofing is a problem particular to CGI programs arising from the fact that the HTML reference to the CGI program may be issued without relation to any particular web page, Consequently, any CGI program implementing an access counter or other auditing or accounting data collecting program can produce an artificially inflated access count from repeated reference to the CGI program HTML statement outside and independent of a proper web page. Access spoofing inherently undermines the apparent if not actual integrity of any data gathered by a CGI program. Since, at minimum, the ability to insure the accuracy of even a simple access count would be of fundamental importance to an Internet service advertiser, the use of CGI programs to provide even basic accounting or auditing functions is of limited practical use. Finally, HTML does not provide a tamper-proof way for two URLs to be accessed in sequence with just one URL reference button, such as, for example, a server CGI counter URL reference followed by external server URL reference. SUMMARY OF THE INVENTION Thus, a general purpose of the present invention is to provide a system and method of reliably tracking and redirecting hyper-link references to external server systems. This is achieved by the present invention through the provision of a message to a tracking server system in response to a client system referencing a predetermined resource locator that corresponds to a resource external to the tracking server system. The tracking server system indirectly provides for the client system to have an informational element selectable by the client system, where the informational element is graphically identified on the client system with informational content obtainable from a content server system through use of a content resource locator. The informational element includes a tracking resource locator, referencing the tracking server system, and data identifying the informational element. The selection of the informational element causes the client system to use the tracking resource locator to provide the data to the tracking server system and to use the content resource locator to obtain the informational content from the content server system. Thus, an advantage of the present invention is that URL reference data is captured in an expedient manner that interposes a minimum latency in returning the ultimately referenced web page while imposing minimum visibility of the redirection protocol on client users. Another advantage of the present invention is that independent invocations of server-external support programs and multiple external data references are not required as a consequence of the present invention, thereby minimizing the CPU and disk intensive load on the web server computer system and the resulting latency. A further advantage of the present invention is that the reference identifier and a redirection directive can both be maintained wholly within the URL specification discretely provided by a client HTML request. Thus, the present invention is superior in both efficiency and maintenance requirements to a CGI counter, or any method that incorporates a CGI counter. Still another advantage of the present invention is that program modifications necessary to support the protocol of the present invention are implemented entirely at the server end of a protocol transaction. Client side participation in the transaction is within the existing client side defined HTML protocol. A still further advantage of the present invention is that the implementation of the invention introduces minimum exposure to additional security breaches due to the closed form of the protocol while providing substantial security against inappropriate URL and protocol references. This is accomplished preferably by the inclusion of validation codes inside the URL specification. BRIEF DESCRIPTION OF THE DRAWINGS These and other advantages and features of the present invention will become better understood upon consideration of the following detailed description of the invention when considered in connection with the accompanying drawings, in which like reference numerals designate like parts throughout the figures thereof, and wherein: FIG. 1 provides a schematic representation of client and server computer systems inter-networked through the Internet; FIG. 2 provides a block diagram of a server computer system implementing an HTTP daemon (HTTPd) server in accordance with a preferred embodiment of the present invention: FIG. 3 provides a flow diagram illustrating the process performed by a preferred embodiment of the present invention in receiving and processing client URL requests; FIG. 4 provides a flow diagram illustrating the server side processing of special redirect URLs in accordance with another preferred embodiment of the present invention; FIG. 5 provides a generalized process representation of client and server computer systems implementing the alternate processes of the present invention; FIG. 6 is a flow diagram illustrating a server-side process that provides for the issuance of a content request message in accordance with a preferred embodiment of the present invention; and FIG. 7 is a flow diagram illustrating a client-side process that provides for the issuance of a tracking message in accordance with a preferred embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION A typical environment 10 utilizing the Internet for network services is shown in FIG. 1 . Client computer system 12 is coupled directly or through an Internet service provider (ISP) to the Internet 14 . By logical reference via a uniform resource locator, a corresponding Internet server system 16 , 18 may be accessed. A generally closed hypertext transfer protocol transaction is conducted between a client browser application executing on the client system 12 and an HTTPd server application executing on the server system 16 . In a preferred embodiment of the present invention, the server system 16 represents an Internet Business Service (IBS) that supports or serves web pages that embed hyper-link references to other HTTPd server systems coupled to the Internet 14 and that are at least logically external to the server system 16 . Within this general framework, the present invention enables the tracking of the selection of embedded hyper-link references by client system 12 . That is, an embedded hyper-link reference is associated with a graphical banner or other Web page element that is selectable, or clickable, by a user of the client system 12 . A banner click on a client system is typically made to obtain information, identified in some fashion by the banner graphic that is of interest to the client system user. Tracking is preferably enabled by embedding HTML information in the Web page served to the client system 12 . This information is served from any prearranged HTTPd server system to the client system 12 . The prearrangement is with an IBS to track banner clicks, on Web pages served by or on behalf of a designated tracking HTTPd server system, such as system 16 , that operates to collect the served page provided tracking information. The embedded information is, in accord with the present invention, sufficient to enable the client computer system 12 to provide tracking information to the HTTPd server system 16 . As will be seen, this information is also sufficient, directly or indirectly, to enable the client computer to request the information associated with the banner graphic. As will also be seen, there are a number of possible implementations of the present invention. These implementations can generally be categorized as predominately using either a server-side or client-side process, as involving proprietary, plug-in, and interpreted control processes, and as using any of a number of specific data transfer protocols. The preferred embodiment of the present invention utilizes a server-side process implemented as a proprietary modification to the HTTPd server application executed by the server system 16 and that uses the HTTP redirection directive. Thus, a web page served by an HTTPd server system, such as the server system 16 or another server system (not shown) to the client 12 embeds a URL reference to a web page served by the logically external server system. Selection of this embedded URL through the client browser of the client computer system 12 results initially in an HTTP transaction with the server system 16 rather than the external server. The information stored in the embedded URL first served with the web page to client system 12 is thus provided back to the server system 16 upon selection of the URL even though the apparent target of the URL is the external server system. A redirection response is then provided by the server system 16 to the client'system 12 providing the corresponding redirection URL. As shown in FIG. 2, the server system 16 receives the redirection request information via a network connection 20 to a network interface 22 within the server system 16 . The network interface 22 is coupled through an internal bus 24 to a central processing unit (CPU) 26 . The CPU 26 executes a network operating system 28 in support of the network interface 22 and other functional aspects of the server system 16 . The network operating system 28 supports the execution by the CPU 26 of an HTTPd server application 30 that defines the responsive operation of the server system 16 to HTTP requests received via the network 20 . Finally, the network operating system 28 provides for temporary and persistent storage of data in a mass storage device 32 preferably including a persistent storage media such as provided by a conventional hard disk drive. In accordance with the preferred embodiment of the present invention, the embedded redirection information provided as part of a URL HTTP request is processed by the HTTPd server 30 . Preferably, the processing by the HTTPd server 30 is performed through the execution of the server 30 itself as opposed to the execution of any external CGI programs or the like. The redirection information is processed by the execution of the server 30 to identify and validate the particular URL reference that provided the redirection information and to generate a redirection target URL. In a preferred embodiment of the present invention, an embedded URL containing redirection information is formatted as follows: http://<direct_server>/redirect?<data>?http://<redirect_server> The direct_server portion of the embedded URL specifies the HTTP server target of a transaction that is to be initially established by the client system 12 The remaining information is provided to the tracking or targeted direct server. The direct server may be any HTTPd server accessible by the client system 12 that has been designated to service redirection requests in accordance with the present invention. The term “redirect” in the embedded redirection URL is a key word that is pre-identified to the HTTPd server 30 to specify that the URL corresponds to a redirection request in accordance with the present invention. Although the term “redirect” is the preferred term, any term or code may be selected provided that the term can be uniquely identified by the HTTPd server 30 to designate a redirection URL. The recognition processing of the “redirect” term is preferably performed through the execution of the server 30 by way of a corresponding modification to the HTTPd server application. That is, the HTTPd server application is modified to recognize the term “redirect” as a key word and to execute a subprogram to implement the server-side process of this preferred embodiment. Alternately, the modification to the HTTPd server application can be implemented as a “plug-in” binary program operative through a conventional interface provided with the HTTPd server application to obtain essentially the same functionality. Although of possibly lesser performance, a server application embedded language, such as Java® or JavaScript®, may be also alternately used to implement the server-side process of recognizing the “redirect” key word and performing the further processing to implement the present invention. The “data” term of the redirection URL provides reference identifier data to the HTTPd server 30 that can be used to further identify and potentially validate a redirection URL to the HTTPd server 30 . The data thus permits an accounting of the redirection URL to be; made by the HTTPd server 30 . In the context of an advertisement, the data may encode a particular advertising client for whom access data may be kept, a particular instance of the graphic image provided to a client system 12 in association with the redirection URL, and potentially a validation code that may serve to ensure that inappropriate client uses of a redirection URL can be distinguished and discarded by the HTTPd server 30 . An exemplary redirection URL, constructed using HTML in accordance with a preferred embodiment of the present invention, is as follows: <a href=“http://www.infoseek.com/IS/redirect?NwPg-003-AA?http://www.newspage.com”> Within the redirection data, the data component “NwPg” serves as a client or account identifier. The data component “003” is a series identifier indicating a particular graphic image that was associated with the redirection URL as embedded in the web page served to the client system 12 . Finally, the data component “AA” may be utilized to provide a basic validation identifier that serves to permit the HTTPd server 30 to identify inappropriate repeated submissions of the redirection URL to the server system 16 or those that are determined to be obsolete by convention. In an alternate embodiment of the present invention, the validation data encodes a data representation that can be used in conjunction with the HTTP protocol to provide information regarding the client system 12 that submitted the redirection URL and, optionally, the graphics series identifier data, to limit repeated use of the redirection URL by the same client system 12 within a defined short period of time. Thus, an inappropriate attempt by a third party client to, in effect, tamper with the data collected by the server system 16 with respect to any particular redirection URL can be identified with relative if not complete certainty and blocked. In addition, date codes older than a certain time interval can be declared by computation to be invalid. Consequently, a copy of the embedded redirection URL cannot be stored on a client system 12 and remain viable for use for longer than a period of time defined exclusively by the server computer system 16 . Each of the data terms within a redirection URL may be statically or dynamically created by the HTTPd server 30 as part of the process of originally serving a web page with the embedded redirection URL to a client computer system 12 . With dynamic generation, different graphic images corresponding to a single advertiser or one of any number of advertisers may be effectively served with an otherwise statically defined web page. The data terms of the embedded redirection URL may be dynamically selected based on the identity of the advertiser and graphics image in addition to separately establishing a hypertext link to the graphics image as part of an instance of serving a particular web page by the HTTPd server 30 . Indeed, the selection of advertiser and graphics image could be made at least in part on the identity of the client computer system 12 as established through information provided by the conventional operation of the HTTP protocol, and on the client profile if known. The validation code may also be dynamically generated. In an alternate embodiment of the present invention, the validation code encodes a representation of the day of the year with the account and image identifier data terms to generate an identifier, preferably encoded as two digits, that provides a sufficient degree of uniqueness to allow an embedded redirection URL to be aged on a per day basis. Furthermore, the validation code remains constant on a per day basis and thereby still permits the number of references on a per day per specific client system 12 basis to be tracked by the HTTPd server 30 so as to limit the frequency that a specific instantiation of the web page is repeatedly presented to a specific client 12 . Additionally, the HTTPd server 30 may operate to block operation on a received redirection URL where the corresponding web page has not recently been served to the requesting client 12 . Various bit shift, check sum, and modulo arithmetic algorithms can be utilized to generate the validation code in a consistent manner known to the HTTPd server 30 , but that cannot be readily discerned upon examination of the resulting redirection URL by a specific client computer system 12 . Alternately, the validation code may be an arbitrarily selected value that is implicitly recognized as valid by the HTTPd server 30 for a programmable period of time from one day to several weeks or longer. In the extreme, and consistent with the initially preferred embodiment of the present invention, the validation code is a static value provided as part of the embedded redirection URL. Independent of the particular manner the validation code is generated or the assigned length of time that the code is recognized by the HTTPd server 30 as valid, evaluation of the data terms of a redirection URL is preferably performed completely internally to the HTTPd server 30 . The data terms are preferably sufficiently complete as to be unambiguous in identifying a particular instantiation of an embedded redirection URL without significant, if any, resort to the loading and execution of an external program or even significantly to interrogate look-up files stored by the persistent storage device 32 . Consequently, the burden of evaluating a redirection URL in accordance with the present invention is almost completely computational in nature. As is conventionally appreciated, the performance of a server computer system 16 is not typically computationally bound, but rather bound by the rate of input/output (I/O) access to the persistent storage device 32 and to the network 20 . By substantially if not completely limiting the evaluation of the redirection URL to a computational operation, with only a limited 110 operation to save auditing or accounting data obtained in connection with a redirection URL, an optimally minimal burden on the server computer system 16 is realized by the operation of the present invention. Indeed, the saving of accounting or auditing data may be cached by the network operating system 28 to defer the write I/O operation to the persistent storage device 32 until otherwise excess I/O bandwidth is available in the ongoing operation of the server computer system 16 . The final portion of the preferred structure of a redirection URL is a second URL. This second URL preferably identifies directly the target server system for the redirection. Preferably, any path portion provided as part of the direct server specification of the redirection URL is repeated as a path component of the redirect server portion of the redirection URL. However, path portion identity is not required. In general, all that is required in accordance with the present invention is a one to one correspondence between the direct server and redirect server terms of the redirection URL. A less strict relationship may be used if the impact upon the auditing or accounting data collected by the operation of the present invention is consistent with the desired characteristic of that data. For example, different direct server specifications may correlate to the use of a common redirect server as a means of further identifying a particular instantiation of an embedded redirection URL. Alternately, otherwise identical instantiations of an embedded redirection URL. may reference any of a number of redirect servers. Thus, the embedded redirection URL provides only an indirect reference to the ultimately servicing redirect server and relies on the direct_server identified server system or the redirect servers themselves to resolve the second URL into a direct reference to an ultimately servicing redirect server. This may be done to distribute load on the cooperatively operating redirect servers or to provide a means for verifying the auditing or accounting data collected by the ongoing operation of the present invention. Indeed, the second URL of a redirection URL can itself be a redirection URL, though care needs to be taken not to create an infinite redirection loop. A preferred method 40 of processing redirection URLs provided to a server computer system 16 by a client computer system 12 is illustrated in FIG. 3 . As each client request is received 42 the data provided as part of the request is examined to determine whether the request embeds the redirect key word 44 . If the URL data does not specify a redirection request consistent with the present invention, the URL data is checked 46 to determine whether the URL data conventionally specifies an existent local web page. If the web page does not exist or, based on the client identification data provided via the HTTP protocol in connection with the URL client request, the particular client is not permitted access to the existent web page, the HTTPd server 30 determines a corresponding error message 48 that is returned to the client computer system 12 . Otherwise, the HTTPd server 30 proceeds and serves the local web page 50 to the client computer system 12 . Where URL data at least specifies a redirection request 52 , the URL data is further checked for validity. A table of valid combinations of client and graphic image identifiers, preferably cached in memory in the server system 16 , may be used to initially establish the validity of the redirection request. The validation code may either be checked by recalculation based on the provided redirection data or checked against another table of validation codes that are current. In either event, the relative timeliness of the redirection request can be determined from the age of the validation code and therefore serve as basis for determining whether the current redirection request is timely or suspect. Furthermore, additional checks may be performed to verify that the corresponding web page has indeed been served recently by the server computer system 16 to the particular requesting client computer system 12 based on a short term log of local web pages actually served by the server computer system 16 . Finally, access permissions enforced by the server computer system 16 can be checked against the identification of the client computer system 12 to categorically limit redirection to defined classes of clients. Where the request is determined to be invalid for any reason, an appropriate denial message is generated and issued 48 . Where a redirection request is determined valid, any or all of the data provided as part of the redirection request or provided to the HTTPd server 30 through the conventional operation of the HTTP protocol can be logged through the network operating system 28 to the persistent storage device 32 for subsequent manipulation, analysis and reporting. The redirection request is then further processed to obtain the second URL identifying the target redirection server 56 . This second URL is then specified in the location field of a redirection message, preferably a temporary redirection message, that is issued 58 back to the client computer system 12 that issued the redirection URL initially. The process 40 in accordance with a preferred embodiment of the present invention, is performed essentially entirely within the HTTPd server 30 . The implementation of the process 40 can be performed through a modification. and extension of the processing flow implemented by the HTTPd server 30 , through a corresponding modification of the server source code. These modifications and additions may be made utilizing conventional programming techniques. The redirection capability provided by the present invention is fully consistent with existent de-facto standard redirection capabilities provided by conventional HTTPd servers. A further detailed portion 60 of the process 40 is shown in FIG. 4 . Within the operation of the HTTPd server 30 , the URL data 62 is received and initially parsed 64 to identify the appropriate existence of the redirect key word. Where the specific form of the redirection URL of the present invention is not identified 66 , the URL is further processed in a conventional manner to determine whether any other form of redirection is applicable. In addition, an evaluation of. conventional access privileges to a local web page where no conventional redirection is specified can also be performed with, ultimately, an appropriate response message being issued 68 . In the specific instance where the URL request is of the special redirect form consistent with the present invention, as opposed to conventional HTML redirection capabilities, the URL data is processed 70 and, in combination with the HTTP protocol-provided data identifying the client computer system 12 , a database record is created or updated in the persistent mass storage device 32 at 72 . The second URL is then extracted 74 and a redirection message, specifically a type 302 temporary redirection message, is prepared. As before, the second URL may be a direct or literal URL or an indirect redirection target server identification that is resolvable by the HTTPd server 30 into a URL that is at least sufficient to identify the target redirection server. Since the second URL, as embedded in a Web page, is defined through prearrangement with the operation of the HTTPd server 30 ; resolution of any indirect redirection target server identification is fully determinable by the HTTPd server 30 through, for example, a database look-up operation. A redirection message including a location field is then created by the HTTPd server 30 . This location field is provided with the direct or resolved target redirection server URL. The redirection message is then issued 58 to the originally requesting client computer system 12 . Other server-side operative embodiments of the present invention can use other specific protocols to transfer the tracking information from the client system 12 to the HTTPd server 30 . These other HTTP protocol methods include, for example, GET, FORMS, OPTIONS, HEAD, PUT, DELETE, AND TRACE. Use of these other protocol methods are generally similar, differing in their requirements for specific browser support for the protocol methods and details of their specific HTML markup coding into Web pages. As an example of the use of these other protocol methods, the HTTP GET method can be implemented by embedding the following HTML code tags in the Web pages served to a client computer system. //HTTP GET <a href=“http://www.infoseek.com/redirect?\ ak=MTCH-2009-1073-GEN&\ rd=http://www.match.com/”> <img src=“http://www.online.com/ads/MTCH1073.gif”> </a> This HTML code defines “MTCH1073.gif” as the Web page banner graphic, “www.infoseek.com” as the direct_URL, “MTCH-2009-1073-GEN” as the data, and “www.match.com” as the target redirection server. When the above HTML tags are served to the client computer system, an initial HTTP GET request is issued to “www.online.com” to obtain the banner graphic. In response to a banner click, a second GET request is directed to “www.infoseek.com” using the URL: /redirect?ak=MTCH-2009-1073-GEN&rd=http://www.match.com/ The complete GET request will be of the form: GET /redirect?ak=MTCH-2009-1073-GEN&\ rd=http://www.match.com/HTTP/1.0 User-Agent: Mozilla/3.0 Accept: image/gif, image/jpeg, */* The HTTPd server 30 records the values of MIME information (such as cookies) and the form variables (in this case ak and rd). An HTTP redirect message is then created by the HTTPd server 30 and returned to the client computer system. A third and final GET request is then issued to “www.match.com” in response to the redirection message. As another example, an HTTP POST method can be used. The Web page embedded HTML tags can be coded as follows: //HTTP POST <FORM method=“POST”\ action=“http://www.infoseek.com/redirect”> <INPUT TYPE=hidden\  NAME=“ak”\  VALUE=“MTCH-2009-1073-GEN”> <INPUT TYPE=hidden\  NAME=“rd”\ VALUE=“http://www.match.com/”> <INPUT TYPE=image\  SRC=“http://www.online.com/ads/MTCH1073.gif”> </FORM> This HTML code will result in a GET request being issued automatically to “www.online.com” to retrieve the banner graphic. A banner click will result in a HTTP POST request being sent to “www.infoseek.com” along with the FORM NAME and VALUE data. In this case, the data is not encoded into the URL, but rather is encoded in the body of the POST request itself. In this example, the POST request will have the form: POST/redirect HTTP/1.0 User-Agent: Mozilla/3.0 Accept: image/gif, image/jpeg, */* Content-type: application/x-www-form-urlencoded Content-length: 54 ak=MTCH-2009-1073-GEN&rd=http://www.match.com/ When the returned redirection message is received, another GET request is issued by the client computer system to the redirection target server, which is again “www.match.com.” In accordance with the present invention, a client-side process can also be utilized to transparently provide notification of the selection of a Web page element by a client computer system. FIG. 5 provides a representation 78 of the data transfer flows involved in both the server-side and client-side processes that implement the present invention. Common to both server-side and client-side process implementations, a client computer system 80 issues an initial Web page request over the Internet (not shown) to a Web page server system 82 . A corresponding Web page 84 including a Web page element 86 is returned to the client computer system 80 . Again, common to both server-side and client-side process implementations of the present invention the Web page element 86 is provided through the embedding of information in the Web page 84 . In the circumstance of a server-side process as generally depicted in FIG. 6, the process of the present invention following from a banner click 96 results in a client browser action. Specifically, the embedded information controls the operation of the Web browser on the client computer system sufficient to issue a notification URL 98 directed to the redirection target server system 88 , as shown in FIG. 5 . The server process 100 initiated in response to the notification URL receipt produces the redirection message that is returned to the client computer system 80 . In connection with the generation of the redirection message, the server system 88 also logs and optionally processes the data received as part of the notification URL 98 . Based on the redirection message, the client computer system 80 then preferably issues an HTTP request 102 based on the:information contained in the redirection message. Referring again to FIG. 5, the HTTP request 102 is provided via the Internet 14 to another Web page server system 90 that responds in a conventional manner by the serving of Web page 92 to the client computer system 80 as the Web page 104 that was inferentially referenced by the Web page element 86 . The method of the present invention utilizing a client-side process is generally shown if FIG. 7 . The method 106 , for the purposes of explanation here, generally begins in response to a banner click 108 to initiate a client process 110 executing in connection with the operation of the Web browser on the client computer system 80 . In a preferred embodiment of the present invention, the client process 110 is provided with the Web page 84 to the client computer system 80 . The client process 110 is invoked in response to the banner click and operates to first issue a notification URL message 112 and, second, to issue an HTTP request 114 . Both messages are issued through the Internet 14 and to the target server system 88 and Web page server 90 , respectively. The order that the client process 110 issues the notification URL 112 and HTTP request 114 is not significant. Further, acknowledgment of the receipt of the notification URL from the target server system 88 is not required prior to issuing the HTTP request 114 . Indeed, as evident to the user of the client computer system 80 , the only response recognized as significant is the receipt 116 of the Web page 92 . As in the case of the server-side process, the client-side process 110 can be implemented in a number of different manners that, for purposes of the present invention, each result in the delivery of data to the target server system 88 and a URL request to a Web page server system 90 to provide a Web page 92 having a prearranged correspondence with the Web page element 86 . Specifically, the client-side process can be directly coded into the browser application or supplied as a browser plug-in to a conventional browser application. The client-side process can also be implemented through use of Java and JavaScript type applets. An exemplary client-side process is implemented through the use of a Java Applet. The HTML code that is embedded in the Web page 84 , for purposes of this example, is as follows: <applet name=“ad” code=“ad.class” width=468 height=60> <param name=img value=“ad.gif”> <param name=notifyurl value=“?MTCH-2009-1073-GEN”> <param name=pageurl value=“http://catalog.online.com/”> </applet > where the three applet parameters are defined as follows: “img”—the URL reference to a graphic banner advertisement “notifyurl”—the “notification” URL holding the accounting data “pageurl”—the “redirection” URL to use The applet source is as follows: import java.applet.Applet; import java.awt.Image; import java.awt.Graphics: import java.net.URL; import java.net.MalformedURLException; import java.io.IOException; public class ad extends Applet { Image image; URL notifyurl; URL pageurl; public void init( ) { image=getImage(getDocumentBase( ), getParameter(“img”)); try { logurl=new URL(getDocumentBase( ), getParameter(“notifyurl”)); pageurl=new URL(getDocumentBase( ), getParameter(“pageurl”)); } catch (MalformedURLException e) {} } public void paint(Graphics g) { g.drawImage(image, 0, 0, this); } public boolean mouseDown(java.awt.Event evt, int x, int y) { try{ logurl.openStream( ).close( ); } catch (java.io.IOException e) {} getAppletContext( ).showDocument(pageurl); return true; } } The above example uses two HTTP requests to first issue the “notifyurl” message and, second, to issue the “pageurl” message. Various other protocols, however, can be used in connection with the present invention. For example, the Java applet can be modified to provide the notification data to the target server system 88 through use of a TCP connection. An exemplary implementation of an applet utilizing a TCP connection is provided below. The applet takes four parameters: “img”—the URL of the ad image to show “port”—the TCP port number to use on the target server “data”—the accounting data to send to the target server “pageurl”—the “redirection” URL to use The applet source is as follows: import java.applet.Applet; import java.awt.Graphics; import java.awt.lmage; import java.io.IOException; import java.io.OutputStream; import java.io.PrintStream; import java.lang.Integer; import java.lang.String; import java.net.MalformedURLException; import java.net.Socket; import java.net.URL; public class ad extends Applet { Image image; String host,data; int port; URL url; public void init( ) { image=getImage(getDocumentBase( ), getParameter(“img”)); host=getDocumentBase( ).getHost( ); port=Integer.parseInt(getParameter(“port”)); data=getParameter(“data”); try {url=new URL(getDocumentBase( ), getParameter(“pageurl”));} catch (MalformedURLException e) {} } public void paint(Graphics g) { g.drawImage(image, 0, 0, this); } public boolean mouseDown(java.awt.Event evt, int x, int y) { try { Socket socket=new Socket(host,port); PrintStream ps=new PrintStream(socket.getOutputStream( )); ps.print(data); ps.close( ); } catch (java.io.IOException e) {} getAppletContext( ).showDocument(url); return true; } } Finally, the above applet can be-referenced for execution by embedding the following HTML code into the Web page 84 . <applet name=“ad” code=“ad.class” width=468 height=60> <param name=img value=“ad.gif”> <param name=port value=“21”> <param name=data value=“MTCH-2009-1073-GEN”> <param name=url value=“http://catalog.online.com/”> </applet> Thus, a comprehensive system and method for accounting or auditing accesses made by client computer systems to external hyper-linked servers has been described. The auditing capabilities of this system process impose optimally minimal overhead burden on the redirection server system while permitting the data that is gathered to be validated and reasonably assured to correspond to bona fide accesses to a redirection target server system. While the invention has been particularly shown and described with reference to preferred embodiments thereof it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

A message is provided to a tracking server system in response to a client system referencing a predetermined resource locator that corresponds to a resource external to the tracking server system. The tracking server system indirectly provides for the client system to have an informational element selectable by the client system, where the informational element is graphically identified on the client system with informational content obtainable from a content server system through use of a content resource locator. The informational element includes a tracking resource locator, referencing the tracking server system, and data identifying the informational element. The selection of the informational element causes the client system to use the tracking resource locator to provide the data to the tracking server system and to use the content resource locator to obtain the informational content from the content server system.

RELATED APPLICATIONS [0001] This is a continuation of U.S. application Ser. No. 11/823,420, titled: “Ultrafast Chirped Optical Waveform Recorder Using Self-Referenced Heterodyning and a Time Microscope” filed Jun. 26, 2007, incorporated herein by reference. This application claims the benefit of U.S. Provisional Application No. 60/817,159, filed Jun. 27, 2006, and U.S. Provisional No. 60/817,172, filed Jun. 27, 2006, which are both incorporated herein by reference. [0002] The United States Government has rights in this invention pursuant to Contract No. DE-AC52-07NA27344 between the United States Department of Energy and Lawrence Livermore National Security, LLC. BACKGROUND OF THE INVENTION [0003] 1. Field of the Invention [0004] The present invention relates to a measurement method and system. More particularly, the present invention relates to a measurement method and system for capturing both the amplitude and phase temporal profile of a transient waveform or a selected number of consecutive waveforms having bandwidths of up to about 10 THz in a single shot or in a high repetition rate mode. [0005] 2. Description of Related Art [0006] Continuous real time recording of ultrafast optical waveforms presents significant technical challenges for conventional electronic analog-to-digital converter (ADC) technology. In general, there are two ways to record such transient waveforms: 1) increase the electrical bandwidth and sample rate, or 2) sample the waveform repetitively. In the latter method for example, ultrafast waveform events are reproduced and sampled repetitively. Samples from different reproductions are combined to reconstruct the waveform. The reproduced displayed waveform is therefore made up of many acquisitions of the signal, similar to that of an analog sampling oscilloscope. This technique does not work for single-shot signals. In the former method, the most obvious way to obtain more samples on the waveform is to increase the sample rate by using faster analog-to-digital converters. However, a typical commercially available state-of-the-art real-time oscilloscope has a resolution on the order of about a 18 ps step response (20 GHz analog bandwidth) and a 20 ps sampling period (50 Gsample/s), making such oscilloscopes undesirable for measuring certain optical waveforms, such as single-shot transient signals, when the desired resolution (step or impulse response duration referred back to the input) requires, for example, a temporal resolution from about 1 ps down to below 100 fs. [0007] Other high-speed detection instruments based on electron streak tubes exist. Unfortunately, these instruments are fundamentally single shot, with a limited record length and slow read out and repetition rate. Such instruments also face space-charge effects which severely limit the usable dynamic range to less than 3.3 bits for 1 ps pulses. [0008] There are also a number of ultrafast pulse measurement techniques, such as, Frequency Resolved Optical Gating (FROG), Spectral Shear Interferometry, correlation techniques, and variations on these, which work well to measure the shape of less than 100 fs pulses. However, such systems and methods have all been demonstrated as scanned systems, which requires a repetitive waveform, or in single-shot systems, which can only record with limited time-bandwidth products. In addition, in the case of single-shot FROG, or other similar systems that map the signal into space, frame capture rates are generally limited by slow readout camera technology. [0009] It should be noted that there are also time stretching concepts related to but dissimilar from the true temporal imaging embodiments discussed herein. One such related technique does not have an input dispersion before the signal is mixed, typically electro-optically with a Mach-Zehnder modulator, with the chirped time lens signal. It has demonstrated large time magnification and fast sampling of electrical waves, but it is limited in the minimum impulse response duration by its GHz bandwidth opto-electronic time lens process and an inherent dispersion penalty which blurs the signal and produces fades in the frequency response. Likewise earlier true temporal imaging systems using electro-optic lenses to impart a frequency chirp are also limited in bandwidth, and thus temporal resolution. In contrast, the novel all optical system presented herein can have many THz of bandwidth and does not have an inherent dispersion penalty. [0010] Accordingly, a need exists for methods and apparatus that can measure ultrafast optical waveforms with a temporal resolution from about 1 ps down to below 100 fs of impulse response width in an expedient and efficient manner. Such a system can record in a single-shot window in time with ultrafast resolution and can be performed at a high repetition rate. Such a technology, combined with one of many demultiplexing techniques, can be used to develop a continuous, greater than THz bandwidth, real time oscilloscope. The present invention is directed to such a need. SUMMARY OF THE INVENTION [0011] Accordingly, the present invention is directed to a self-referenced time lensing method that includes: providing one or more desired signals; providing one or more chirped time lens pump pulses to optically mix with the one or more desired signals; temporally magnifying the optically mixed one or more desired signals; and measuring a time-scaled replica of intensity and/or frequency information of the one or more desired signals with a temporal resolution of down to about 44 fs with waveform fidelity, precision, and dexterity better than about 5%. [0012] Another aspect of the present invention is directed to a self-referenced time microscope configured to provide a time-scaled replica of the intensity and/or frequency information contained in one or more received desired signals. [0013] Still another aspect of the present invention is directed to a heterodyning self-referenced time microscope recording system configured to provide as well as record a time-scaled replica of the intensity and/or frequency information contained in one or more received desired signals. [0014] Accordingly, the present invention provides optical and THz arrangements and methods for capturing both the amplitude and phase of an optical waveform by adding heterodyning, which may as one arrangement, be self-referenced, to convert frequency chirp into a time varying intensity modulation to enable the measurement of one or more heterodyne beat frequencies of up to about 10 THz that change on about a 1 ps time scale. By also including a variety of possible demultiplexing techniques, such a process is also scalable to recoding continuous signals. [0015] It is to be appreciated that the methods and apparatus of the present invention are further adapted to simultaneously convert the carrier frequency of a signal from one region of the electromagnetic spectrum to another. Applications include, but are not limited to: recording of signals that requires below about 1 ps impulse response temporal resolution; high-energy physics and high-energy density physics experiments; the study of ultrafast molecular dynamics; sub-diffraction-limit imaging (e.g. synthetic aperture imaging and inverse synthetic aperture imaging); and in ultra-wideband optical communications. BRIEF DESCRIPTION OF THE DRAWINGS [0016] The accompanying drawings, which are incorporated into and constitute a part of the specification, illustrate specific embodiments of the invention and, together with the general description of the invention given above, and the detailed description of the specific embodiments, serve to explain the principles of the invention. [0017] FIG. 1 shows an example time domain plot of a pulse intensity and frequency chirp for the present invention. [0018] FIG. 2 a illustrates beam spreading due to paraxial diffraction. [0019] FIG. 2 b illustrates pulse spreading due to narrow-band dispersion. [0020] FIG. 3 a illustrates a lens in space for comparison with the lens in time of FIG. 3 b . Both impart a quadratic phase in their real space coordinate. [0021] FIG. 3 b illustrates a lens in time for comparison with the lens in space of FIG. 3 a . Both impart a quadratic phase in their real space coordinate. [0022] FIG. 4 shows an example self-heterodyne and temporal imaging diagram of an ultra-fast chirp pulse recording system of the present invention. [0023] FIG. 5 show results for a chirped 1.8 nm FWHM input pulse at 1534.0 nm (229 GHz FWHM bandwidth) as produced by configurations of the present invention. [0024] FIG. 6 show results for intensity of the pulse recorded single shot (3 separate measurements, 240 GHz bandwidth) in comparison to a time averaged measurement done with a sampling oscilloscope (40 GHz detector limited). [0025] FIG. 7 shows an example diagram of a beneficial system of the present invention simultaneously recording both the time magnified heterodyne beat signal in FIG. 4 and a time magnified version of the intensity profile. DETAILED DESCRIPTION OF THE INVENTION [0026] The present invention is directed to a time-domain approach in which the entire spectrum is processed and captured collectively. Thus, the present invention provides a time-domain measurement system and method which can capture both the intensity profile and the frequency chirp of a transient optical or THz waveform or waveforms having a high repetition rate in a single shot format. Specifically, the methods and apparatus of the present invention are adapted to simultaneously convert the carrier frequency of a signal from one region of the electromagnetic spectrum to another. This may be from one optical band to another, or between THz and optical bands, or between any other bands between which sum-frequency-generation (SFG), difference-frequency-generation (DFG), or coherent higher order mixing process is possible. As long as the required dispersion can be produced at what ever the local carrier frequency is, temporal imaging can be achieved while simultaneously converting the signal from one spectral region to another. [0027] Such a method and system, as disclosed herein, are fundamentally different than frequency domain approaches that capture a wideband signal only after it has been sliced into many narrow channels. Instead of trying to record the ultrafast waveform(s) directly, embodiments of the present invention utilize photonic processing to transform a desired signal into a format compatible with conventional high-speed electronic recording systems. [0028] Such a method and system, as disclosed herein, are also fundamentally different than other time stretching systems which do not have an input dispersion and do not balance the input, output, and focal dispersions according to an imaging condition. The temporal imaging in this system does not suffer from fades in the frequency response, nor introduce phase shifts between frequency components, which blur the impulse response. The temporal imaging system(s) and method(s) of the present invention are capable of fs impulse response, referred back to the input, and when combined with heterodyning can record heterodyne beat periods on this time scale. [0029] To determine a frequency chirp, the desired signal is mixed with a narrow band reference signal, for example a single longitudinal mode, which is directed from a separate or the same optical source from which the signal was generated, thus producing a heterodyne beat signal or a self-referenced heterodyne beat signal at the instantaneous frequency difference between the desired signal being recorded and the reference frequency. When utlizing a reference frequency derived from the source laser system, spectral components are locked in phase by the lasers mode-locking process and any frequency drift in the signal is tracked by the same drift in the reference. As another arrangement, a non self-referenced, heterodyne reference laser can also be used, but in such a case the phase of the beat signal drifts at a rate inversely proportional to the linewidth of the reference laser. It is to be appreciated that such a heterodyne beat is dramatically different from conventional heterodyning not only in terms of the higher frequencies being measured (up to about 10 THz instead of below about 20 GHz), but also in terms in the speed at which this beat is changing (on a ps time scale instead of slower than about 1 ns). It is also to be appreciated that such a beat signal is beyond the speed of real-time digitizers for recordation purposes. Therefore, to record either the beat signal or the original intensity profile of the ultrafast optical waveforms, such waveforms are magnified in time using techniques described herein, which enables such waveforms to maintain their shape on a transformed time scale and enables such magnified waveforms to be recorded with conventional high speed electronics with the benefit of having a system input resolution determined primarily by the ultrafast optical front end. [0030] Accordingly, using hardware and techniques of the present invention, an input signal as illustrated in FIG. 1 . can be recorded. The signal can be chirped to spread the spectrum and evenly fill a desired time frame, such as the 100 ps time frame illustrated in FIG. 1 . By blocking the reference signal (e.g., the narrow band reference), a temporal image of an input optical intensity waveform 2 (as indicated by the left vertical axis) can be recorded. By not blocking the reference, a temporal image of a chirped beat which changes at the same rate as the chirp 4 , i.e., the instantaneous frequency vs time information, as indicated by the right vertical axis) can be produced and recorded. Applicable bandwidths that can be resolved by the present application often include up to about 300 GHz, more often up to about 10 THz with down to about 44 fs resolution and with waveform fidelity (amplitude and phase uncertainty), precision (shot-to-shot waveform reproducibility), and dexterity (A-B-A-B reproducibility) better than about 5%. Given an input field E in (τ) expressed in a reference frame where τ=0 is the center of the pulse; [0000] E in  ( τ ) = A in  ( τ )  exp  (   ( ω 0  τ + bτ  2 2 + φ ) ) ( 1 ) [0000] where A in (τ) is the amplitude profile, ω 0 is the center carrier frequency, and b is the chirp parameter. The instantaneous frequency of the waveform is ω(τ)=ω 0 +bτ. If this is added to the continuous wave field; [0000] E ref (τ)= A ref exp( iω ref τ)  (2) [0000] the resulting intensity profile is: [0000] I h  ( τ ) =  A in  ( τ )  2 +  A ref  2 + 2  A ref  A in  ( τ )  cos  ( ( ω 0 ′ - ω ref )  τ + bτ  2 2 + φ ) . ( 3 ) [0031] When the reference amplitude is close to that of the input amplitude, a strong beat is observed. When the beat is stronger than variations in the input amplitude profile a fit of the argument in the cosine to match the positions of the maxima and minima determines the chirp. It is to be appreciated that an exact match of the fringe amplitudes is not required to determine the chirp accurately. It is only necessary to match the beat oscillation frequencies. Higher order chirp curvature can also be included. In cases where there is strong modulation in the input amplitude A in (τ), a separate recording (done simultaneously, as described below) of the input waveforms intensity profile can be used to determine the amplitude of the cosine term and produce a more accurate fit. [0032] Many numerical techniques can be used to process the captured heterodyne beat signals and acquire the desired frequency vs time information (chirp). These include, but are not limited to, direct calculation of beat periods from maxima and minima, least mean squared error fitting, Fourier Transform processing, Wigner Transforming, Wavelet transforms, and Sonogram approaches. [0033] Both the input intensity profile and beat signal described above are too fast to record with a conventional photodetector and electronic digitizer directly. The next sections describe how desired signals can be magnified in time by the present invention before recording. Space-Time Analogy [0034] The temporal magnification technique of the present invention is based on a space-time duality between how a beam of light spreads due to diffraction as it propagates in space and how pulses of light disperse (spread) as they propagate through dispersive media. As known to those of ordinary skill in the art, a variety of dispersive elements, such as, for example, prism systems, optical fiber, a non-linear crystal, a free space grating, a waveguide, an arrayed waveguide grating with feedback, a volume of dispersive material (e.g., gas, solid, or liquid), an array of ring resonators, a Gires-Tournois interferometer (GTI), a fiber Bragg grating, and/or a planar waveguide Bragg grating can all be used to generate dispersive delay lines and can thus be incorporated into the configurations and methods disclosed herein. Since the equations describing narrow-band dispersion have the same mathematical form as those for paraxial diffraction, dispersion can perform the role of diffraction in the temporal equivalent to an imaging system. [0035] FIG. 2 a and FIG. 2 b illustrates the space-time duality described above, wherein the graphic in FIG. 2 a shows the evolution of the transverse spatial field profile in x as it propagates in z, and FIG. 2 b shows the temporal profile of a pulse as it spreads in the local time coordinate r as it propagates the distance 4 . Both can be seen to impart a quadratic spectral phase to their respective frequency domains, ε (k x ,z) and A(Ω,ξ), where k x is a transverse spatial frequency component and Ω=ω−ω 0 is an optical frequency component relative to the carrier. In space the strength of the diffraction depends on the distance and the wavevector k=2πn/λ. In the time domain, the strength of the dispersion depends on the distance and the materials (or systems) group velocity dispersion (GVD) β″=d 2 β(ω)/dω 2 | ω=ω 0 40 or the total group delay dispersion (GDD) can be written φ″=ξβ″=dτ g (ω)/dω| ω=ω 0 . It should also be noted that combinations of different dispersive elements may be combined to cancel higher order dispersion (spectral phase terms), satisfying the narrow-band approximation even for extremely wide bandwidths. [0036] There is also a one-to-one analogy between the quadratic spatial phase modulation produced by a space lens 5 , as shown in FIG. 3 a and imparting of a quadratic temporal phase (equivalent to a linear frequency chirp), as shown by the time lens of FIG. 3 b . Any process that can impart such a temporal phase profile can act as the time domain equivalent of a lens in space. Electro-optic and cross-phase modulation time lenses have been demonstrated, but they generate weak lenses with short time apertures and are thus not well suited to recording long waveforms with the novel ultra-fast detail of the present invention. [0037] Accordingly, a time lens is implemented herein, as shown in FIG. 3 b , through mixing of an input signal 6 with a broadband-chirped optical pump 8 to impart a quantity of quadratic phase curvature (equivalent to a linear frequency chirp). This mixing is generated through sum-frequency generation, difference-frequency generation, or higher order mixing process such as, but not limited to, four wave mixing of the input and pump signals in a nonlinear material 9 (e.g., GaSe, ZnGeP, GaP, LiNbO3, LiTaO3, PPLN, PPSLN, PPLT, PPSLT, KNbO3, LBO, BIBO, CLBO, KTP, GaAs, GaSe, ZnGeP, GaP, Si, Silica fibers/waveguides, doped fibers/waveguides and/or many other nonlinear materials). In space, those skilled in the art think of the focal length f for a refractive lens, as shown in FIG. 3 a , as the propagation distance required after the lens, for plane wave illumination that removes the imparted phase curvature in order to focus the beam to a small spot. This focal length is defined in a material (often air) and at a wavelength which has the corresponding wavevector k. [0038] Likewise, the temporal focal length ξ f , as shown in the equations of FIG. 3 b , is considered to be the propagation length required in a material (or system) with GVD, β″ after the time lens, for continuous wave input that removes the imparted phase curvature and thus compresses the light to short pulses. In systems where the GVD is constant, such as those using only one type of optical fiber, it is convenient to work with focal length parameter ξ f , but in others it is simpler to just consider the total focal GDD φ f ″, as shown in FIG. 3 b. Temporal Imaging of Optical Waveforms [0039] Analogous to its spatial-counter-part, a system that can expand (or compress) arbitrary temporal waveforms is thus produced by cascading dispersive propagation, time lens modulation, and further dispersive propagation, in the proper balance according to the temporal imaging condition [0000] 1 φ 1 ″ + 1 φ 2 ″ = 1 φ f ″ , ( 4 ) [0000] where φ 1 ″ is the input GDD, φ 2 ″ is the output GDD, and φ f ″ is the focal GDD, respectively. The output waveform is then a temporally scaled replica of the input waveform, [0000] A out  ( τ ) ∝ A in  ( τ M )  exp  ( -    τ 2 2  M   φ f ″ ) , ( 5 ) [0000] with a magnification [0000] M=−φ 2 ″/φ 1 ″.  (6) [0040] It is to be appreciated that if the GVD characteristics of the material is constant, such GDD ratios are reduced to ratios of propagation lengths, similar to spatial imaging. The magnification of the signal in time also reduces the bandwidth of each temporal feature (pulses), but the quadratic temporal phase in Eqn. (5) represents the fact that the chirp imparted by the time lens, divided by the magnification, remains in the temporal image. It is also to be appreciated that such a process is completely coherent, with both the input amplitude and phase profiles being scaled by the magnification. [0041] With the definition of focal GDD, φ f ″=(−dω/dτ) −1 as given in FIG. 3 b , where dω/dτ is the time lens pump pulse chirp, the results above, strictly speaking, apply to the case of sum-frequency generation (SFG) time lens mixing. In the case of difference frequency generation (DFG) mixing, or higher order processes, the spectrum of the input signal may be inverted or the imparted chirp may have an opposite sign to that of the pump. Table 1 below outlines changes in the imaging condition, carrier frequency shift, and resulting magnification for the SFG and DFG cases. [0000] TABLE 1 Time Lens Output Imaging Image Type Carrier Condition Magnification A out (τ) ∝ SFG (or EO) ω 2 = ω 1 + ω p (ω 0 ) 1 φ 1 ″ + 1 φ 2 ″ = 1 φ f ″ M = - φ 2 ″ φ 1 ″ = 1 1 - ( φ 1 ″ / φ f ″ ) A in  ( τ M ) DFG, Pump − Input ω 2 = ω p − ω 1 - 1 φ 1 ″ + 1 φ 2 ″ = 1 φ f ″ M = + φ 2 ″ φ 1 ″ = 1 1 + ( φ 1 ″ / φ f ″ ) A in *  ( τ M ) DFG, Input − Pump ω 2 = ω 1 − ω p 1 φ 1 ″ + 1 φ 2 ″ = - 1 φ f ″ M = - φ 2 ″ φ 1 ″ = 1 1 + ( φ 1 ″ / φ f ″ ) A in  ( τ M ) [0042] The above are all χ (2) nonlinear processes. It is also possible to create a time lens through coherent higher order processes, such as, but not limited to χ (3) . With a strong pump the Four Wave Mixing (FWM) process E 2 ∝χ (3) ·E p E p E 1 *; produces an output at carrier ω 2 =2ω p −ω 1 and imparts twice the chirp rate of a DFG, Pump-Input case above. Two photons of the pump are combined with one photon from the input to produce one photon for the output instead of one photon from each being involved. In this case the factor of two on the imparted chirp and the complex conjugate of the signal change the imaging condition to [0000] - 1 φ 1 ″ + 1 φ 2 ″ = 2 φ f ″ . [0000] At this focusing condition the input field A in (τ) will produce a complex conjugate and time magnified output A out (τ)∝A in *(τ/M) when the magnification is M=+φ 2 ″/φ i ″. This is very similar to the case of DFG pump-input parametric temporal imaging except that the effective time lens strength is doubled (half the focal dispersion) and the frequency shift of the carrier is much less. A benefit of this type of time lens mixing is that it can be very efficient over a broad spectral band without the use of periodic poling. Fabrication tolerances in periodic poling can lead to ripple in the mixing conversion efficiency. This source of distortion does not exist in four wave mixing temporal imaging. [0043] In an application where it's desirable for all signals to stay at a wavelength in the highly utilized telecom S-, C- and L-bands, where large volumes of components are produced and industry supports component development, this FWM time lens mixing configuration has the benefit of keeping the output signal in these bands if the input and pump are also in this band. In these bands large dispersion-to-loss ratios are available with specialty fibers. This alleviates the need for a chirped fiber Bragg grating at the output and removes distortions due to fabrication tolerance induced ripple in the grating delay and reflectivity. [0044] The same physics which produces FWM also produces self phase modulation (SPM). This could distort the time lens pump pulse and cause aberrations in the system. This problem could be minimized my using a flat topped, or super Gaussian, intensity profile for the time lens pump. SPM induced distortions would occur on the edges of the time lens pulse and cause little to no effect in the center where most of the energy passes through the time lens process. [0045] In an ideal system, the ultimate limit to the input resolution of a system as disclosed herein having a large magnification is the duration of the pump pulse if it is transform limited instead of chirped; e.g., if the pump pulse (e.g., having a configured flat top or super-Gaussian time lens pump pulse intensity profile) has a bandwidth of a 25 fs pulse and everything else is ideal, then the temporal imaging system equates to an input resolution limit of 25 fs. The derivation of this assumes a Gaussian time lens aperture and defines two elements as being resolved when they are separated in time by the duration of the systems impulse response. Thus, if the input waveform has the same bandwidth as the time lens pump, the field of view (temporal record length) is approximately the duration of the chirped pump pulse. The number of resolvable points is therefore given by the time lens pump pulses stretch factor, the chirped pump's duration over its transform limited duration. The present invention also includes filtering effects due to the transmission of various optical components and group velocity mismatch in the nonlinear crystal. These filtering effects can both reduce the aperture time and blur the image, depending on their location in the system. [0046] Efficient conversion requires phase matching of all frequency components in the input 6 , pump 8 , and output 11 signals. In the presence of group velocity mismatch and group velocity dispersion, this can be difficult to do over a broad bandwidth. The crystal 9 is typically required to be shorter than in narrower band applications, also reducing the efficiency. Both the input waveform 6 and pump pulse 8 are dispersed (e.g., via, for example, Fiber Bragg Gratings, or wound optical fibers) to obtain the desired time lens phase profile and to focus the imaging system, thus their peak intensities are reduced. These conditions are all contrary to those desired for good conversion efficiency. For a given energy of the time lens pump pulse this results in a fundamental trade off between conversion efficiency in the crystal (and thus system loss) and the maximum per pump pulse input time aperture (frame length). The present invention provides solutions using higher energy pump lasers and optical amplification. Another example arrangement is to reduce the input time aperture per pump pulse and run the system at a higher repetition rate. [0047] Yet another solution is to utilize quasi-phase matched nonlinear materials such as, but not limited to, periodically poled lithium niobate (PPLN) and aperiodically poled lithium niobate (A-PPLN). Much higher effective nonlinear susceptibility can be achieved with these devices than in bulk crystals. The poling period can also be chirped to obtain higher conversion efficiency in different parts of the device for different wavelength ranges, thus improving the overall efficiency across the entire bandwidth. Waveguides can also be written into such PPLN devices. This maintains a tighter mode confinement over a longer interaction length, also increasing the conversion efficiency. [0048] Turning back to the drawings, a diagram that illustrates an exemplary embodiment of a system having an input signal sensitivity from about 5 pJ down to about 5 fJ per 100 ps input frame (temporal field of view), or about 50 mW down to about 50 μW peak optical power, as constructed in accordance with the present invention, is shown in FIG. 4 . The system, designated generally by the reference numeral 50 , and capable of being designed as a portable compact apparatus, generally includes a signal generation or acquisition unit 12 , an optical source 14 , a fiber coupler 18 , a pulse picker 22 , as well as a first 26 and a second 30 optical dispersion element (such as, for example, a chirped fiber Bragg grating (used in reflection with an optical circulator or fiber coupler), or a prism or grating pair system. However, while such optical dispersive elements are beneficial, the present invention can also utilize any dispersive material that can induce the proper amount and kind of dispersion required for the present application, such as, for example, a configured pair of wound optical fibers to induce a predetermined dispersion effect. [0049] System 50 also includes a pair of optical amplification means 34 , such as, but not limited to, Erbium doped Fiber amplifiers, a nonlinear interaction optical device 38 , such as, but not limited to, a periodically poled Lithium Niobate waveguide or an aperiodically poled lithium niobate (A-PPLN) as discussed above, an output dispersion means 42 (e.g., wound optical fiber, prism or grating pair systems, dispersive material, but often a chirped fiber Bragg gratings used in reflection with an optical circulators or fiber coupler, etc.), a detector 46 , such as, for example, a photodiode, an amplified photoreceiver, a photomultiplier, a charge coupled device (CCD), etc., and/or any imaging device constructed to the design output parameters for system 50 , and an analyzing means 52 , such as a real-time oscilloscope, for analyzing the time magnified waveforms as received by detector 46 . Other components can replace one or both of 46 and 52 , such as optical streak cameras, with significant trade-offs in the bandwidth, dynamic range, and repetition rate of the system. [0050] The signal generation or acquisition unit 12 is configured to either receive a single-pulse transient signal or a number of such pulses or is configured to generate said waveform from the optical source 14 . It may be configured to induce the received modulation onto a reference signal directed from optical source 14 (as shown by the dashed path denoted by the letter S) or directed from a separate independent source) via for example, an integrated-waveguide interferometric modulator (e.g., a LiNbO3 Mach-Zehnder modulator), or modulating sensor unit. It may also be designed to generate ultrafast arbitrary waveforms from said source 14 , which require real-time measurement and verification as to their precision, accuracy, and stability. The optical source 14 itself is often designed to be a laser, often a mode-locked laser, arranged to output about 100 mW of average optical power and capable of outputting a wavelength range between about 800 nm and up to about 2 micron, more often between about 1.310 nm and up to about 1650 nm so as to also include the S, C, and L bands commonly utilized in the telecom industry. Many other wavelength bands may also be used. While a number of optical sources can be incorporated into the present invention, a beneficial source includes a mode-locked Pritel model UOC laser system lasing at 1534 nm at 620 MHz with output pulse-widths of down to about 1 ps. Another beneficial arrangement for the optical source 14 includes integration of an octave spanning carrier-envelope locked system currently under development at Massachusetts Institute of Technology (MIT). In such an arrangement, signal and pump pulses can be chosen from slightly shifted sections of the broadband laser. [0051] While source 14 shows one common source for improved stability, it is also possible for separate and varied types of sources to be used. For example, a narrow line-width (e.g., 1 MHz or less) Distributed Feedback laser (DFB) laser, or tunable single-longitudinal optical sources, such as, but not limited to, Distributed Bragg Reflectors, Sampled Grating DBRs, Grating-assisted Co-directional Couplers with Sampled Reflectors, and Vertical Cavity Surface Emitting Lasers capable of operating within the designed parameters may also be utilized when operating within the scope and spirit of the present invention. Narrow band sources can be used as the heterodyne reference or be modulated by an ultrafast event as part of signal generation or acquisition unit 12 . The time lens pump pulse is required to have a broad bandwidth in order to obtain good temporal resolution. A broadband Modelocked laser source can be used directly or narrow band sources as mentioned earlier can be modulated with high speed amplitude and phase modulators to spectrally broaden the signals. In addition, example arrangements with such sources as disclosed herein also include utilizing solution compression in dispersion-decreasing fiber to simultaneously broaden the bandwidth and shift the wavelength (e.g., to shift from 1534 nm to 1558 nm) of a chosen pump signal to preclude deleterious effects, such as degenerate collinear sum-frequency mixing in the non-linear crystal embodiments of the present invention. Other nonlinear processes such as self phase modulation may also be used to broaden the spectrum of the pump signal. [0052] Turning back to FIG. 4 , in the method of the invention, a desired waveform to be recorded (not shown) is generated by the signal generation or acquisition unit 12 . It may be by way of an induced modulation of an electromagnetic radiation beam directed from optical source 14 (as denoted by the dashed path line S), or by an ultrafast modulation of an independent source. The induced modulated signal as produced from signal generation or acquisition unit 12 is directed along path A (shown with a directional arrow). A narrowband reference signal (preferably generated from optical source 14 in conjunction with a filtering means 16 (e.g., one or more narrow band filters, edge filters, long pass and short filters, etc.)) is directed along path B (shown with a directional arrow) for use in heterodyning (via optical coupler 18 ) with the induced signal directed along path A. Upon heterodyning, the resultant signal is further directed to the Signal & Heterodyne reference path 19 (as shown by the dashed box), which includes being directed through optical dispersive element 26 to induce a predetermined amount of dispersion into the signals received from optical coupler 18 . Thereafter, the heterodyned signal is amplified via amplifier 34 to make up for losses resulting from upstream elements. [0053] A third signal directed along path C (also denoted with an accompanying directional arrow) includes a broadband pulse also generated from optical source 14 and is directed to the time-lens pump pulse path 23 (also shown with a dashed box). As shown within the time-lens pump path 23 , a pulse picker 22 , such as a Mach Zehnder modulator or any electro-optic modulator or acousto-optic modulator having a suitable electronic driver, is configured in the pump pulse path of the example embodiment for system 50 to reduce the rate of the time lens pump thereby causing, for example, only 1 out of 4 (rate adjustable) of desired input signals to be up-converted and recorded at the output. The three dispersive delay lines in the system are adjusted according to temporal imaging conditions as per equation 4, as discussed above, to focus the system and produce a time-scaled replica at the output of the waveform at the input with, for example a suitable temporal magnification of up to about +/−100×. The nonlinear interaction optical device 38 is configured to impart the chirp of the time lens pump thereby generating a time lens. The FBG/Circulator (or directional coupler) configuration imparts the image dispersion and the time magnified signal is received by detector 46 and captured by an available scope capable of resolving such magnified images of the present invention. [0054] The present invention will be more fully understood by reference to the following examples, which are intended to be illustrative of the present invention, but not limiting thereof. [0055] FIG. 5 shows results for a recorded chirped 1.8 nm FWHM input pulse 70 (shown as a dashed line) at 1534.0 nm (229 GHz FWHM bandwidth) as produced by configurations of the present invention. A CW signal at 1534.7 nm is added at the input to convert the frequency chirp into the chirped heterodyne beat 70 . Also shown in FIG. 5 are the calculated oscillation frequencies 74 (shown as a series of black circles) for the adjacent minima in 70 and a linear fit 78 (shown as solid line) to match the positions of the maxima and minima so that the chirp can be determined. The pulse 70 recorded at the output had been temporally magnified by a factor of −30.09× and recorded on a high speed photo-receiver and an 8 GHz real time scope. The −3.45 GHz/ns chirped beat signal 70 recorded on the oscilloscope indicates an initial input with an optical frequency chirp of 312.9 GHz/100 ps. This is a 240 GHz bandwidth single shot measurement system that currently repeats at 990 KHz. [0056] FIG. 6 show results for intensity of the pulse recorded single shot (3 separate measurements, 240 GHz bandwidth) in comparison to a time averaged measurement done with a sampling oscilloscope (40 GHz detector limited). In particular, this is a measurement of just the intensity profile (only the reference is off) when the heterodyne reference is turned off using the configuration, as shown in FIG. 4 . Each trace (i.e., # 1 , # 2 , and # 3 , as denoted by reference numerals 80 , 84 , and 88 respectively) are obtained single-shot measurements (as referenced by the left vertical scale) as made approximately 30 seconds apart using an example temporal imaging magnification of −30.09×, a 12 GHz receiver, and a Tektronix TDS6804B 8 GHz scope having an effective Bandwidth of 240 GHz. The resultant data 80 , 84 , and 88 show fast temporal details and changes in the signal from pulse to pulse which can not be recorded with a sampling scope, as referenced by the right vertical scale. The heavy line trace 92 is a signal recorded on a repetitive, time averaged basis with a 40 GHz photodiode and 50 GHz sampling oscilloscope. The overall profile matches well. The sampling scope measurement was made later in the day and the circled region 96 level change is consistent with changes in the laser system (e.g., drift) that were observed. Again, the temporal imaging system measurements 80 , 84 , and 88 , as referenced by the left vertical scale, show faster details and are each single shot measurements of one pulse, whereas the data 92 referenced by the right vertical scale is a repetitively averaged measurement of many pulses which blurs some of the faster details. [0057] FIG. 7 shows another beneficial example system having input signal sensitivities from about 5 pJ down to about 5 fJ per 100 ps input frame (temporal field of view), or about 50 mW to 50 μW peak optical power. Such a system, designated generally by the reference numeral 700 , is adapted to simultaneously record both the time magnified heterodyne beat signal, as discussed above and as shown in FIG. 4 , and a time magnified version of the intensity profile. It is to be noted that common reference numbers denoted in FIG. 4 are utilized where similarly appropriate in FIG. 7 . [0058] For example, system 700 generally includes a signal generation or acquisition unit 12 , an optical source 14 , a pulse picker 22 , as well as a first 26 and a second 30 optical dispersion element (such as, for example, a chirped fiber Bragg grating (used in reflection with an optical circulator or fiber coupler), or a prism or grating pair system. However, while such optical dispersive elements are beneficial, the present invention can also utilize any dispersive material that can induce the proper amount and kind of dispersion required for the present application, such as, for example, a configured pair of wound optical fibers to induce a predetermined dispersion effect. [0059] System 700 also includes a pair of optical amplification means 34 , such as, but not limited to, Erbium doped Fiber amplifiers, a nonlinear interaction optical device 38 , such as, but not limited to, a periodically poled Lithium Niobate waveguide or an aperiodically poled lithium niobate (A-PPLN), an output dispersion means 42 (e.g., wound optical fiber, prism or grating pair systems, dispersive material, but often a chirped fiber Bragg gratings used in reflection with an optical circulator or fiber coupler, etc.), a detector 46 , such as, for example, a photodiode, an amplified photoreceiver, a photomultiplier, a charge coupled device (CCD), etc., and/or any imaging device constructed to the design output parameters for system 700 , and an analyzing means 52 , such as a real-time oscilloscope, for analyzing the time magnified waveforms as received by detector 46 . Other components can replace one or both of 46 and 52 , such as optical streak cameras, with significant trade offs in the bandwidth, dynamic range, and repetition rate of the system. [0060] Similar to the example configuration of FIG. 4 , the signal generation or acquisition unit 12 , as shown in FIG. 7 , is configured to either receive a single-pulse transient signal or a number of such pulses or is configured to generate said waveform from the optical source 14 . It may be configured to induce the received modulation onto a reference signal directed from optical source 14 (or directed from [0061] a separate independent source) via for example, an integrated-waveguide interferometric modulator (e.g., a LiNbO3 Mach-Zehnder modulator), or modulating sensor unit. It may also be designed to generate ultrafast arbitrary waveforms from said source 14 , which require real-time measurement and verification as to their precision, accuracy, and stability. The optical source 14 itself is often designed to be a laser, often a mode-locked laser, arranged to output about 100 mW of average optical power and capable of outputting a wavelength range between about 1310 nm and up to about 1650 nm so as to also include the S, C, and L bands commonly utilized in the telecom industry. Many other wavelength bands may also be used. While a number of optical sources can be incorporated into the configuration of FIG. 7 , a beneficial source includes a harmonically mode locked sigma laser lasing at 1534 nm at 620 MHz with output pulsewidths of down to about 1, ps. Another beneficial arrangement for the optical source 14 includes integration of an octave spanning carrier-envelope locked system currently under development at Massachusetts Institute of Technology (MIT). In such an arrangement, signal and pump pulses can be chosen from slightly shifted sections of the broadband laser. [0062] As also similarly discussed above with reference to FIG. 4 , source 14 in FIG. 7 shows one common source for improved stability but it is also possible for separate and varied types of sources to be used. For example, a narrow line-width (e.g., 1 MHz) Distributed Feedback laser (DFB) laser, or tunable single-longitudinal optical sources, such as, but not limited to, Distributed Bragg Reflectors, Sampled Grating DBRs, Grating-assisted Co-directional Couplers with Sampled Reflectors, and Vertical Cavity Surface Emitting Lasers capable of operating within the designed parameters of the present invention. [0063] Turning exclusively to the beneficial configuration of FIG. 7 , in the method of the invention, a desired waveform to be recorded (not shown) is generated by the signal generation or acquisition unit 12 . It may be by way of the induced modulation of an electromagnetic radiation beam directed from optical source 14 or by an ultrafast modulation of an independent source. The induced modulated signal as produced from signal generation or acquisition unit 12 is directed along path A (i.e., shown with a directional arrow) and is further directed along the top leg denoted within a dashed box as Signal Path 19 ″). Signal path 19 ″ can be referred to as the input dispersion path, which includes being directed through optical dispersive element 26 to induce a predetermined amount of dispersion into the directed signals received and thereafter, the signal having an induced input dispersion is amplified via amplifier 34 to make up for losses resulting from upstream elements. [0064] The signal received form amplifier 34 is split into two paths (denoted as K and K′) by a splitter 21 , often a 50/50% splitter. One such split signal K′) is directed into a first time lens crystal 38 ′, e.g., a periodically poled Lithium Niobate waveguide or an aperiodically poled lithium niobate (A-PPLN) waveguide. The second portion of the split signal (K) is received and further directed by a first coupler 18 ′ into a second time lens crystal 38 , e.g., a periodically poled Lithium Niobate waveguide or an aperiodically poled lithium niobate (A-PPLN) waveguide. [0065] A middle path (i.e., Heterodyne Reference Path 19 ′, as shown within a dashed portion) is configured to combine the signal received from a narrowband reference signal (often generated from optical source 14 in conjunction with a filtering means 16 (e.g., one or more narrow band filters, edge filters, long pass and short filters, etc.)) with a split portion (K) from one of the dispersed inputs as directed from the Signal Path 19 ″ (i.e., after the input dispersion instead of before the input dispersion, as in FIG. 4 ) via an optical coupler 18 ′, which can then be received by crystal 38 for producing a time lens output using the heterodyne reference path 19 ′ signal. [0066] The very bottom leg is the path of the chirped time lens pump pulse 23 , as discussed above and as shown in FIG. 4 , except that it is split along two paths (denoted as L and L′ by splitter 21 ′, often a 50/50 splitter) to drive the two mixing time lens crystals 38 ′ and 38 respectively. The top crystal path (i.e., through crystal 38 ′) produces the normal time lens output when there is no heterodyne reference and the bottom crystal (i.e., crystal 38 ) produces a time lens output for the case with the heterodyne reference. The signals are time delayed relative to each other, (e.g., via optical delay 39 ) so that they do not overlap and then go through a final coupler 41 and then a common output dispersion 42 . Such an arrangement allows for the same input dispersion, output dispersion, and time lens pump to be used on both the temporal image of the signal and of the heterodyned signal. Thus, the magnifications are the same and any distortions are common to both. [0067] Applicants are providing this description, which includes drawings and examples of specific embodiments, to give a broad representation of the invention. Various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this description and by practice of the invention. The scope of the invention is not intended to be limited to the particular forms disclosed and the invention covers all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the claims.

A new technique for capturing both the amplitude and phase of an optical waveform is presented. This technique can capture signals with many THz of bandwidths in a single shot (e.g., temporal resolution of about 44 fs), or be operated repetitively at a high rate. That is, each temporal window (or frame) is captured single shot, in real time, but the process may be run repeatedly or single-shot. This invention expands upon previous work in temporal imaging by adding heterodyning, which can be self-referenced for improved precision and stability, to convert frequency chirp (the second derivative of phase with respect to time) into a time varying intensity modulation. By also including a variety of possible demultiplexing techniques, this process is scalable to recoding continuous signals.

This application claims the benefit of Russian Application No. 2011116257, filed Apr. 26, 2011 and is hereby incorporated by reference in its entirety. FIELD OF THE INVENTION The present invention relates to event timers generally and, more particularly, to a method and/or apparatus for implementing a timer manager architecture based on a binary heap. BACKGROUND OF THE INVENTION Some conventional timer managers implement a binary heap. Each element in the binary heap represents a single expiration time. The expiration times are presented as a one-dimensional linear array. The array stores the expiration times according to the following properties and equations: A root of the heap is located at array index 0, and A node at array index N: Has a “left child” at array index 2N+1; Has a “right child” at array index 2N+2; and Has a parent at array index floor((N−1)/2). The timer manage commonly support large streams of request to create a new timer and delete an existing timer. Two sort procedures are used to implement the create requests and the delete requests. A bubble-up sort procedure is used when an element is added to the heap. The steps of the bubble-up procedure are as follows: Step 1. Add a new element to an empty heap location next to a current “tail of the heap”. The tail of the heap is located at a bottom level of the heap in accordance with a shape property of the heap. Step 2. Compare the element being sorted with a parent of the element according to a comparison predicate. If the heap property criteria is satisfied, sorting is complete. Step 3. If not, swap the heap location of the element being sorted and the parent and continue with step 2. A bubble-down sort procedure occurs as a side-effect of removing the element at the root of the heap. The steps of the bubble-down procedure are as follows: Step 1. Move the element currently located at the tail of the heap to the root of the heap. Step 2. Declare the root as an element being sorted. Step 3. Compare the two children of the element being sorted to each other according to the comparison predicate. Step 4. Compare the “winning child” from step 3 to the element being sorted according to the comparison predicate. If the heap property is satisfied, the sorting is complete. Step 5. If not, swap the heap location of the winning child with the element being sorted (the parent of the winning child) and continue with step 3. The reading, comparing, swapping and writing of the elements to and from the array often takes considerable time until the sorting criteria is satisfied. Therefore, conventional time managers can take a long time to add elements to the heap and delete elements from the heap. Furthermore, the minimum period between successive expiration times is unacceptably long due to the bubble-down sort delays. It would be desirable to implement a timer manager architecture based on a binary heap that supports a short minimum timer period and/or adds and deletes timers rapidly from the binary heap. SUMMARY OF THE INVENTION The present invention generally concerns an apparatus having a first memory and a circuit. The first memory may be configured to store a plurality of timers. Each of the timers may have a respective value that indicates an expiration time. A first one of the timers nearest to expiring is generally stored at a first address of the first memory. The circuit may be configured to (i) assert a signal in response to the respective value of the first timer matching a counter of time, (ii) read a second of the timers and a third of the timers both from a second address of the first memory, (iii) sort the second timer and the third timer to determine which expires next and (iv) replace the first timer by writing one of the second timer or the third timer that expires next into the first memory at the first address. The objects, features and advantages of the present invention include providing a timer manager architecture based on binary heap that may (i) implement a short minimum timer period (e.g., 3 clock cycles), (ii) create new timers faster than the common techniques, (iii) delete existing timers faster than the common techniques, (iv) arrange the binary heap in a two-dimensional array, (v) occupy a low silicon area compared with common designs and/or (vi) utilizes multiple memories. BRIEF DESCRIPTION OF THE DRAWINGS These and other objects, features and advantages of the present invention will be apparent from the following detailed description and the appended claims and drawings in which: FIG. 1 is a diagram of an example binary minimum heap; FIG. 2 is a block diagram of an apparatus in accordance with a preferred embodiment of the present invention; FIG. 3 is a diagram of an example distribution of the contents of a timer queue memory; FIG. 4 is a flow diagram of an example implementation of a main process; FIG. 5 is a diagram of the timer queue memory after an enqueue process has been performed; and FIG. 6 is a diagram of the timer queue memory after a requeue process has been performed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In some embodiments of the present invention, a timer manager may be used to maintain N general purpose timers (e.g., 2≦N≦1024) relative to a count value incremented by a clock signal. The timer manager generally supports at least two timer commands, a create command and a delete command. When a new timer is created, timer configuration information may be stored by the timer manager in a memory circuit. The timer configuration information generally includes a start time parameter, a timer type parameter, a timer period parameter and event information. The start time parameter generally defines an initial expiration time for the timer. The timer type may be a parameter that indicates either a one-shot type of timer or a periodic type of timer. If the timer type is a one-shot timer, an event signal may be asserted and the one-shot timer may be deleted when or after the expiration time occurs. If the timer type is a periodic timer, the event signal may be asserted and a next timer expiration time is calculated for the timer when or after the periodic timer expiration time occurs. The next expiration timer is generally defined as a sum of the current expiration time and the timer period. If the next expiration time exceeds a maximum count value, the maximum count value may be subtracted from the next expiration time. The reduction of the next expiration time may be designed to match a roll over of the count value of the clock cycles. A timer may enter an enqueue process from one of two possible events, a creation of a new timer (e.g., enqueue) or a requeue of an expired periodic timer. Each periodic timer may be requeued each time that the periodic timer expires. Therefore, the requeue process generally does not apply to one-shot timers. When a timer expires, the event information may be used to initialize an event described by the event information. When a timer delete request is received by the timer manager, the timer to be deleted may be marked by a “should be deleted” condition (or state). When a should-be-deleted timer expires, the associated event may not be initialized and the timer may be deleted. Referring to FIG. 1 , a diagram of an example binary minimum heap 100 is shown. The heap 100 may be organized into multiple layers. A single element 102 generally resides at a top layer. Two elements 104 a - 104 b may reside in a next layer below the top layer. The elements 104 a - 104 b may be children of the parent element 102 . Four elements 106 a - 106 d may be located two layers below the top layer. The elements 106 a - 106 b may be children of the parent element 104 a . The elements 106 c - 106 d may be children of the parent element 104 b . In the example, two elements 108 a - 108 b of eight possible elements may reside at a lowest level. The elements 108 a - 108 b may be children of the parent element 106 a . The element 108 b may be a current tail element of the heap 100 . A heap location 110 that may be used in an enqueue operation is generally an empty location next to the current tail element (e.g., 108 b ). The heap 100 generally illustrates a heap size of nine (e.g., nine of the heap locations may have the corresponding elements 102 - 108 b ) and a depth of four levels. Other size and depths of the heap 100 may be implemented to meet the criteria of a particular application. Each element (or solid circle) shown generally represents a sorted timer. Numerical values illustrated in the top half of the timers 102 - 108 b may be the respective expiration times. Timer identification values (e.g., timer_ID) shown in the lower half of the timers 102 - 108 b may be an identification code used to link the timers 102 - 108 b to the configuration information. The heap 100 generally comprises a heap data structure created using a binary tree with two additional constraints. An additional constraint may be a shape property. The tree is generally a complete binary tree where all levels of the tree, except possibly the last level (e.g., deepest or lowest level) are fully filled. Furthermore, if the last level of the tree is not complete, the nodes of the last level may be filled from left to right. Another additional constraint may be a heap property. Each node may be greater than or match each corresponding child node according to a comparison predicate, which is fixed for the entire data structure. For the timer manager, the comparison predicate may be based on the expiration times. Moreover, the comparison predicate may be a “less than or equal to” predicate (e.g., a minimum heap structure). Therefore, the timer corresponding to each node may always have an earlier or matching expiration time compared with each of the children of the respective node. The following variables may be used to explain the operation of the timer manager. The variable N may be a maximum number of general purpose timers. The variable N is generally an integer power of 2, for example N=1024. A variable W may be a width (e.g., number of bits) of each timer_ID. The width may be calculated as W=log 2 (N−1). For example, if N=1024, W=log 2 (1023)=10 bits. A variable T_W may be a width (e.g., number of bits) of the expiration times and the start times. Typical values of the variable T_W may be 32, 24 or 16 bits. A variable P_W may be a width (e.g., number of bits) of the timer period. Example values of the variable P_W may be 31, 30 or 29 bits. A variable E_W may be a width (e.g., number of bits) of the event information. Other widths may be implemented for the variables to meet the criteria of a particular application. Referring to FIG. 2 , a block diagram of an apparatus 120 is shown in accordance with a preferred embodiment of the present invention. The apparatus (or device, circuit or integrated circuit) 120 generally implements a timer manager. The apparatus 120 may comprise a block (or circuit) 122 , a block (or circuit) 124 and a block (or circuit) 126 . The circuits 122 - 126 may represent modules and/or blocks that may be implemented as hardware, firmware, software, a combination of hardware, firmware and/or software, or other implementations. A signal (e.g., CLK) may be received by the circuit 122 . The signal CLK may convey a system clock to the circuitry within the circuit 120 . A signal (e.g., TIME) may be received by the circuit 122 . The signal TIME generally conveys the current count value of the number of clock cycles. In some embodiments, a counter of the clock cycles may be implemented within the circuit 122 and the signal TIME may be eliminated. A signal (e.g., EVENT) may be generated by the circuit 122 . The signal EVENT may have an asserted state (or condition) when a timer has expired and a deasserted state (or condition) otherwise. In some embodiments, the asserted state may be indicated by the circuit 122 transmitting the event information of the just-expired timer in the signal EVENT. The circuit 122 may communicate bidirectionally with the circuit 124 via a signal (e.g., CONFIG). A signal (e.g., QUEUE) may provide bidirectional communications between the circuit 122 and the circuit 126 . The circuit 122 generally implements a timer manager circuit. The circuit 122 may be operational to compare a respective value of the next timer to expire with the time count value received in the signal TIME. When the respective value of the next timer to expire matches the time count value in the signal TIME, the circuit 122 may assert the signal EVENT. The circuit 122 may also read two additional timers both from a same address of the circuit 126 . The two additional timers may be sorted to determine which timer expires next. Once the next timer to expire has been determined, the circuit 122 generally replaces the just-expired timer by writing the next-to-expire timer into the circuit 126 at the same address of the just-expired timer. The circuit 122 may implement several processes (or methods) that add timers to the heap 100 and delete timers from the heap 100 . Adding timers generally involves an enqueue (or create or bubble-up) process in which a new timer is added to an empty location (e.g., the location 110 ). The newly added timer may be compared with a parent timer in a parent location (e.g., the location 106 b ). If the newly added timer expires before the parent timer, the two timers are swapped in the heap 100 . If the newly added timer expires at the same time or later than the parent timer, the enqueue process may be ended. The above comparison is generally repeated between a child timer and a parent timer (e.g., bubbles up the heap 100 ) until the child timer expires at the same time or after the parent time. Deleting timers generally involves a requeue (or bubble-down) process in which the timer at the root location is to be removed from the heap 100 . The timers that are the children (e.g., timers 104 a - 104 b ) of the timer to be removed (e.g., the timer 102 ) may be read from the circuit 126 to the circuit 122 and compared with each other. The child timer with the earlier expiration time (e.g., the winning child timer) is generally written into the root location of the heap 100 . The children of the winning child timer may be subsequently read from the circuit 126 and compared. The new winning child generally takes the place of the original winning child in the heap 100 . The comparison process may continue comparing lower pairs of children (e.g., bubbles down the heap 100 ) until all of the timers have been sorted. The circuit 122 may contain multiple registers 134 . When data is stored in a register 134 , the data is generally available from the register 134 at a next clock cycle. If a name of a register is designated as one or more characters (e.g., R), the data stored in and presented by the register R may be denoted as data R. The registers 134 may include, but are not limited to, the following registers: A register (e.g., H_MIN) may be used to store timer information (e.g., expiration time and timer_ID) for the timer with the minimal expiration time. A width of the register H_MIN is generally (T_W)+W bits. Other timer information may be stored in the circuit 126 as a binary heap tree. An expiration time field of the register H_MIN may be denoted as H_MIN.ET. A timer identification field of the register H_MIN may be demoted as H_MIN.ID. A register (e.g., C_MIN) may be used to store timer configuration information for the timer where the timer_ID matches the timer field H_MIN.ID. The register C_MIN generally contains a copy of the contents stored at the address H_MIN.ID of the circuit 124 . A width of the register C_MIN may be (P_W)+(E_W)+2 bits. A timer period field of the register C_MIN may be denoted as C_MIN.P. A timer type field of the register C_MIN may be denoted as C_MIN.T. An event information field of the register C_MIN may be denoted as C_MIN.E. A should-be-deleted field of the register C_MIN may be denoted as C_MIN.D. A register (e.g., E_B_S) is generally used to store the timer being sorted. A width of the register E_B_S may be (T_W)+W bits. An expiration time field of the register E_B_S may be denoted as E_B_S.ET. A timer identification field of the register E_B_S may be denoted as E_B_S.ID. A register (e.g., N_B_S) may be used to store the index of the timer being sorted. A width of the register N_B_S may be W bits. A register (e.g., R_T_Q) is generally used to store read data from the circuit 126 . A width of the register R_T_Q may be 2×((T_W)+W) bits. When a read command is sent to the circuit 126 , the read data generally appears at the circuit 122 at a next clock cycle. In the circuit 122 , the read data may be immediately stored in the registers 134 . Thereafter, the read data may be available from the registers 134 two clock cycles after the read command is issued. A register (e.g., P_E_B_S) may be used to store a timer forming a pair timers related to the timer being sorted. A width of the register P_E_B_S may be (T_W)+W bits. An expiration time field of the register P_E_B_S may be denoted as P_E_B_S.ET. A timer identification field of the register P_E_B_S may be denoted as P_E_B_S.ID. A register (e.g., H_S) is generally used to store a current number of sorted, active timers. If H_S=1, the circuit 126 may be empty. If H_S>1, the number of sorted timers the circuit 126 may be (H_S)−1 timers. The value (H_S)−1 may be the index of the binary heap array suitable to locate a new timer. An initial value in the register H_S may be zero. A width of the register H_S may be W bits. A register (e.g. F_S) may be used to store a current number of all timers, both active and suspended. A value (F_S)−(H_S) may be the number of suspended timers. The suspended timers may be located in the circuit 126 after the tail element of binary heap 100 . An initial value stored in the register F_S may be zero. A width of the register F_S is generally W bits. A register (e.g., BUSY_FLAG) generally indicates that some binary heap process is either in progress (e.g., a busy state or busy condition) or not in progress (e.g., an idle state or idle condition). A width of the register BUSY_FLAG may be 1 bit. A register (e.g., IS_LEAF) is generally used to store whether the node is a leaf (e.g., a leaf state or leaf condition) or not a leaf (e.g., a non-leaf state or non-leaf condition). A width of the register IS_LEAF may be 1 bit. A register (e.g., PARENT_ID) is generally used to store an index value of the node being sorted. A width of the register PARENT_ID is generally W bits. The circuit 124 may implement a memory circuit. In some embodiments, the circuit 124 may be deigned as a single-port Random Access Memory (RAM) circuit. The circuit 124 is generally operational to store a configuration word 128 for each of the timers 102 - 108 b . Each configuration word 128 may comprise a respective configuration data (or item) 130 and a respective flag 132 . The circuit 124 may have N addresses. At each address, the circuit 124 may store the configuration word 128 of a respective one of N possible timers. Storage of the configurations word 128 generally parallels the timer identification numbers. For example, a timer with a timer identification of zero may be stored in the circuit 124 at the address zero. A timer with a timer identification of one may be stored in the circuit 124 at the address one. A timer with a timer identification of two may be stored in the circuit 124 at the address two, and so on. The configurations words 128 may be written to and read from the circuit 124 via the signal CONFIG. A width of the circuit 124 may be (P_W)+(E_W)+2 bits, where P_W is the width of the timer period and E_W is the width of the event information. The configuration data 130 generally contains the timer period and the event information. The flags 132 generally contains either a should-be-deleted condition (or state or logical 0) or an active condition (or state or logical 1). Each flag 132 holding the should-be-deleted condition generally indicates that the associated timer should be deleted upon expiration. Each flag 132 holding the active condition generally indicates that the event information associate with the timer should be executed upon expiration. An initial value of each flag 132 may be zero (e.g., should-be-deleted condition). The circuit 126 may implement another memory circuit. In some embodiments, the circuit 126 may be deigned as a single-port RAM circuit. The circuit 126 is generally operational to store the timers 102 - 108 b . Each timer 102 - 108 b generally has a respective value that indicates when the timers expire. Each timer 102 - 108 b may also have the timer identification value. The timer closest to expiring (e.g., timer 102 ) may be stored in the circuit 126 at the base (or zero) address of the circuit 126 . The circuit 126 generally stores the timers 102 - 108 b in a binary minimum heap structure. To improve sorting times, in particular the requeue process durations, the binary heap structure may be represented by a two-dimensional array. The array may be disposed in the circuit 126 such that both children of a node may be located at the same addressable entry (e.g., row) of the circuit 126 . The upper-half of an addressable entry generally maintains “left child information”, while the lower-half of the addressable entry maintains “right child information”. Therefore, the apparatus 120 (the circuit 122 ) may determine the properties using the following properties and equations: The root of the heap 100 may be located at array index 0=address 0 in the circuit 126 (e.g., right child); The node at array index N=address (floor(N/2)+P), where P=1 if N is odd (e.g., a left-child), and P=0 if N is even (e.g., a right-child); If the node is a left-child located in the upper-half of the entry at an address M of the circuit 126 (N is odd): The left-child node viewed as a parent may have a “left child” at array index 2N+1=address 2M (e.g., upper-half entry); The left-child node viewed as a parent may have a “right child” at array index 2N+2=address 2M (e.g., lower-half entry); and The left-child may have a parent at array index floor((N−1)/2)=address M/2. The parent may be a “left-child” (e.g., upper-half entry) of another node if mod (M/2)=0. The parent may be a “right-child” (e.g., lower-half entry) of another node if mod (M/2)=1; If the node is a right-child located in the lower-half of the entry at the address M of the circuit 126 (N is even): The right-child node viewed as a parent may have a “left child” at array index 2N+1=address 2M+1 (e.g., upper-half entry); The right-child mode viewed as a parent may have a “right child” at array index 2N+2=address 2M+1 (e.g., lower-half entry); and The right-child may have a parent at array index floor((N−1)/2)=address M/2. The parent may be a “left-child” (e.g., upper-half entry) of another node if mod (M/2)=0. The parent may be a “right-child” (lower-half entry) of another node if mod (M/2)=1. Referring to FIG. 3 , a diagram of an example distribution of the contents of the circuit 126 is shown. The contents may illustrate the binary minimum-heap depicted in FIG. 1 . Each address (row, entry or word) in the circuit 126 generally contains information for two timers 102 - 108 b (e.g., the information corresponding to both children of a node). For each timer/child, the circuit 126 may maintain a timer expiration time parameter 136 a (left child) or 136 b (right child) and a timer identification parameter 138 a (left child) or 138 b (right child). A width of the circuit 126 may be 2×((T_W)+W) bits, where T_W may be the width of the expiration timer and start time. A size (or depth) of the circuit 126 may be N/2 addressable lines (rows or words), where N is the maximum number of timers supported. Returning to FIG. 2 , the circuit 122 may include several built-in functions. The functions may include, but are not limited to, the following functions (or operations): Loc(N)=(N+1)/2. If N is a number of the binary heap array index, the function Loc(N) may be the address in the circuit 126 where the node with index N is located. Mod(N)=mod(N). If N is odd, mod(N)=1. The odd N generally means that binary heap node with the index N is a “left-child” (upper-half entry in the circuit 126 ). If N is even, mod(N)=0. The even N generally means that the binary heap node with index N is a “right-child” (lower-half entry in the circuit 126 ). Val(N) may be the contents of the lower-half entry of the circuit 126 at the address Loc(N) if mod(N)=0. Val (N) may be the contents of the upper-half entry in the circuit 126 at the address Loc(N) if mod(N)=1. TwinVal (N) may be the contents of the upper-half entry of the circuit 126 at the address Loc(NY if mod(N)=0. TwinVal(N) may be the contents of the lower-half entry of the circuit 126 at the address Loc(N) if mod(N)=1. Father(N)=(N−1)/2 is generally the index of the parent of the node with the index N. FatherLoc(N)=Loc(Father(N))=Loc(N)/2. If N is a number of the binary heap array index, the function FatherLoc(N) may return the address of the circuit 126 where the parent of the node with the index N is located. FatherVal(N)=Val((N−1)/2) may return the contents of the parent of the node with the index N. ChildrenLoc(N)=2×Loc(N)+1-mod(N) may return the location address of the children of the node with the index N. LeftChild(N)=2N+1 may be the index of the left child of the node with the index N. RightChild(N)=2N+2 may be the index of the right child of the node with the index N. LeftChildVal(N)=Val(2N+1) may be the contents of the left child of the node with the index N. RightChildVal(N)=Val(2N+2) may be the contents of the right child of the node with the index N. Referring to FIG. 4 , a flow diagram of an example implementation of a main process 140 is shown. The process (or method) 140 may be executed by the circuit 122 . The process 140 generally comprises a step (or state) 142 , a step (or state) 144 , a step (or state) 146 , a step (or state) 148 , a step (or state) 150 , a step (or state) 152 , a step (or state) 154 , a step (or state) 156 , a step (or state) 158 , a step (or state) 160 and a step (or state) 162 . The steps 142 - 162 may represent modules and/or blocks that may be implemented as hardware, firmware, software, a combination of hardware, firmware and/or software, or other implementations. In the step 142 , the circuit 122 may determine if a value of a system timer (e.g., the signal TIME) matches H_MIN.ET (e.g., the expiration time of the next timer to expire). If the time and H_MIN.ET match (e.g., the YES branch of step 142 ), the circuit 122 may assert the signal EVENT in the step 144 . The assertion of the signal EVENT generally conveys the event information from the register C_MIN. If the time and H_MIN.ET are different (e.g., the NO branch of the step 142 ), the process 140 may continue with the step 146 . In the step 146 , the circuit 122 may determine if a delete timer request has occurred. If at least one delete request has occurred (e.g., the YES branch of step 146 ), the circuit 122 may activate a delete process in the step 148 . If no delete timer request has occurred (e.g., the NO branch of step 146 ), the process 140 may continue with the step 150 . The step 150 generally checks for the occurrence of a create timer request. If at least one create request occurs (e.g., the YES branch of step 150 ), the circuit 122 may activate a create (enqueue) process in the step 152 . In no create requests have been received (e.g., the NO branch of step 150 ), the process 140 may continue with the step 154 . In the step 154 , the circuit 122 may check the register BUSY_FLAG and the signal TIME. If the value BUSY_FLAG=0 and the value of system timer is not less than H_MIN.ET (e.g., the YES branch of step 154 ), the circuit 122 may activate a requeue process in the step 156 . If the value BUSY_FLAG=1 or the value of the system timer is less than the value H_MIN.ET (e.g., the NO branch of step 154 ), the process 140 may continue with the step 158 . The circuit 122 may check the registers BUSY_FLAG, F_S and H_S in the step 158 . If the value BUSY_FLAG=0 and F_S>H_S (e.g., the YES branch of step 158 ), the circuit 122 may start the enqueue process for the suspended timers in the step 160 . The circuit 122 may also set the value BUSY_FLAG=1 and set the value N_B_S=H_S in the step 160 . A read command may be sent to the circuit 126 to read the contents from the address Loc(H_S) in the step 160 . The circuit 122 may also set the value H_S=H_S+1. If the value BUSY_FLAG=1 or F_S<H_S (e.g., the NO branch of step 158 ), the process 140 may continue with the step 162 . The step 162 may be executed in a next clock cycle of the circuit 122 . The contents of the circuit 126 read from the address Loc (N_B_S) may be received by the circuit 122 . The circuit 122 may store the value Val(N_B_S) to the register E_B_S. The circuit 122 may store the value TwinVal(N_B_S) to the register P_E_B_S. The function FatherLoc( ) may calculate FatherLoc(N_B_S). The circuit 122 may send a read command to the circuit 126 for the contents at the address FatherLoc(N_B_S). The step 162 may end with a jump to a step 3 of the enqueue process. Delete Process: The delete process may include the following steps: Step 1. A “Delete” command received by the circuit 122 from external circuitry (e.g., a processor or CPU) may initiate the delete process. Let a value (e.g., ID) be the value of the timer_ID being deleted. Step 2. If H_MIN.ID=ID, set C_MIN.D=1 and activate the requeue process. If H_MIN.ID≠ID, set in the circuit 124 at the address ID the FLAG=1 (e.g., the should-be-deleted condition). Step 3. End the delete process. Enqueue Process: The enqueue (create or bubble-up) process may include the following steps: Step 1. A “Create” command received by the circuit 122 generally initiates the bubble up process, Let a value C be a timer configuration. A value C.ID may be the timer_ID. A value C.S may be the start time. A value C.T may be the timer type (e.g., one-shot or periodic). A value C.P may be the timer period. A value C.E maybe the event information. Step 1a. The circuit 122 may aggregate information to write in circuit 124 in the following arrangement (C.P, C.T, C.E, 0). The aggregate (C.P, C.T, C.E, 0) may be written in the circuit 124 at the address C.ID. Step 1b. Calculate the expiration time of a new timer E_T=T+(C.S), where T may be a current system time. The value ID of the new timer_ID may be set to C.ID. Step 1c. An information value pair (E_T, ID) for the binary heap 100 may be stored to the register E_B_S. Step 1d. If the value H_S=0, the timer may be an initial timer in the heap 100 . The value pair (E_T, ID) is generally stored in the register H_MIN. The aggregated values (C.P, C.T, C.E, 0) may be stored in the register C_MIN. The storing may stop if complete, else the sorting may continue to step 1e. Step 1e. Compare the value E_T with the value H_MIN_ET. If the value E_T<H_MIN.ET, the value pair (E_T, ID) may be stored in the register H_MIN and the values(C.P, C.T, C.E, 0) may be stored in the register C_MIN. The value E_T may be set to H_MIN.ET and the value ID may be set to H_MIN.ID (e.g, the values H_MIN and (E_T, ID) may be swapped.) Step 1f. If the value H_S>1 and the value BUSY_FLAG=1, the previous binary heap process is generally paused and the value pair (E_T, ID) may be written in the circuit 126 at the address (F_S)+1. The value F_S may be set to (F_S)+1. The process may continue at the step 2a. Step 1g. If the value H_S>1 and the value BUSY_FLAG=0 and the value F_S>H_S, the value pair (E_T, ID) may be written in the circuit 126 at the address (F_S)−1. The value F_S may be set to (F_S)+1. The enqueue process may be stopped, otherwise continue with step 1h. Step 1h. If the value H_S=1, the value pair (E_T, ID) may be written in the circuit 126 at the address 0 and the process stopped, else continue with step 1i. Step 1i. A case generally remains where the value H_S>1 and the value BUSY_FLAG=0 and the value F_S=H_S. Occurrence of the case generally means that the enqueue process should be started. In the step 1i, the value BUSY_FLAG may be set to 1. The value N_B_S may be set to (H_S)−1. Step 1j. If the value (H_S)−1 is even, the circuit 122 may read the twin child timers (elements) for the timer being sorted. Therefore, a read command may be sent to the circuit 126 for the contents at the address Loc((H_S)−1). The value H_S may be set to (H_S)+1. If the value (H_S)−1 is even, the process may continue at the step 2b, else the process may continue with step 1k. Step 1k. If the value (H_S)−1 is odd, the circuit 122 may calculate FatherLoc ((H_S)−1) and send a read command to the circuit 126 for the contents at the address FatherLoc((H_S)−1). The value H_S may be set to (H_S)+1. If the value (H_S)−1 is odd, the process may continue with the step 3, else the process may continue with step 2. Step 2. During a next clock cycle: Step 2a. The circuit 122 may continue the previous binary heap process and stop the enqueue process. Step 2b. The circuit 126 may present the contents from the address Loc(N_B_S). The value TwinVal (N_B_S) may be stored to the register P_E_B_S. The circuit 122 may calculate FatherLoc(N_B_S) and send a read command to the circuit 126 to read the contents from the address FatherLoc(N_B_S). The process may continue with step 3. Step 3. During a next clock cycle: The circuit 126 generally presents the requested content from the address FatherLoc(N_B_S) to the circuit 122 . The circuit 122 may store the contents received from the circuit 126 to the register R_T_Q. The process may continue with step 4. Step 4. During a next clock cycle: The register R_T_Q may contain and present the contents copied from the circuit 126 at the address FatherLoc(N_B_S). The circuit 122 may compare the values E_B_S.ET and FatherVal(N_B_S).ET (e.g, FatherVal(N_B_S) may be either the left part or the right part of the register RT_Q as appropriate). The value FatherVal(N_B_S).ET≦E_B_S.ET generally means that the heap property criteria is satisfied. Therefore, the values E_B_S and P_E_B_S may be written in correct order into the circuit 126 to the address Loc(N_B_S). The value BUSY_FLAG may be set to zero and the process may stop. The value FatherVal(N_B_S).ET>E_B_S.ET generally means that the timer being sorted and a parent timer should be swapped. If the value Father(N_B_S)=0 (parent of root), a set of value ((0,0), E_B_S) may be written in the circuit 126 to the address 0. The process may continue to step 5a. The values (0,0) may mean that upper-half entry of the circuit 126 at the address 0 is not used and so may be set any value (e.g., the values (0,0)). If the value Father(N_B_S)>0, the value FatherLoc(Father(N_B_S)) may be calculated by the circuit 122 and a read command may be sent to the circuit 126 for the contents from the address FatherLoc(Father(N_B_S)). The process may continue at step 5b. Step 5. During a next clock cycle: Step 5a. Write the values P_E_B_S and FatherVal(N_B_S) (in correct order) in the circuit 126 to the address Loc(N_B_S). The circuit 122 may set the value BUSY_FLAG to zero and stop. Step 5b. Write the values P_E_B_S and FatherVal(N_B_S) (in correct order) in the circuit 126 to the address Loc(N_B_S). The circuit 122 may store the value TwinVal(Father(N_B_S)) in the register P_E_B_S. The circuit 126 generally presents the contents from the address FatherLoc(Father(N_B_S)) to the circuit 122 . The contents received by the circuit 122 may be stored in the register R_T_Q. The value N — B_S may be set to Father(N_B_S). The process may continue with the step 4. Based on the above steps, the enqueue process generally works for no more than 2×(log 2 ((H_S)−1)−1)+3=2×log 2 ((HS)−1)+1 clock cycles to add the new timer. Consider the following example application of the enqueue process for a case where the values H_MIN.ET=502, H_MIN.ID=4 and BUSY_FLAG=0. The circuit 126 may be as described in FIG. 3 with the binary heap 100 described in FIG. 1 . A current system clock cycle (e.g., value of the system timer in the signal TIME) may be 100. A create timer request may occur for a new timer with values start time=601 and timer_ID=11. During the 100-th clock cycle: a) The new timer information may be written in the circuit 124 at the address 11 (e.g., timer_ID). b) An expiration time E_T may be calculated as 601+100=701 clock cycles. c) A value pair (E_T=701, timer_ID=11) may be stored to the register E_B_S. d) Since the value H_S=10 is greater than zero and the value H_MIN_ET=502 is less than 701, the enqueue process may be started. e) Set the value BUSY_FLAG=1. Set the value N_B_S=H_S−1=9. f) The value H_S−1=9 is odd. Therefore, the value FatherLoc(9) may be calculated as 10/4=2. A read command may be sent to the circuit 126 to read the contents from the address 2. g) Set the value H_S=11. During the 101-th clock cycle: a) The circuit 126 generally presents the contents for the two timers ((E_T=6243, Timer_ID=2),(E_T=4455, Timer_ID=8)) located at the address 2 to the circuit 122 . The contents may be stored in the register R_T_Q. During the 102-th clock cycle: a) The register R_T_Q may present the values ((E_T=6243, Timer_ID=2), (E_T=4455, Timer_ID=8)). b) The value Father(N_B_S)=Father(9)=8/2=4. The value FatherVal(N_B_S).ET=4455. c) Since the value FatherVal(N_B_S).ET=4455 is greater than the value E_B_S.ET=701 and the value Father(N_B_S)=4 is greater than zero, the value FatherLoc(Father(N_B_S)) may be calculated as 5/4=1. A read command may be sent to the circuit 126 for the contents from the address 1. During the 103-th clock cycle: a) The values((E_T=4455, Timer_ID=8), P_E_B_S) may be written in the circuit 126 to the address Loc(N_B_S)=10/2=5. Note that the value P_E_B_S may be undefined at the time of the writing. b) The value TwinVal(Father(N_B_S))=(E_T=6243, Timer_ID=2) may be stored in the register P_E_B_S. c) The circuit 126 may present the values ((E_T=2123, Timer_ID=3), (E_T=3234, Timer_ID=10)) in response to the earlier read command. The values received by the circuit 122 may be stored in the register R_T_Q. d) Set the value N_B_S=Father(N_B_S)=4. During 104-th clock cycle: a) The register R_T_Q may present the values ((E_T=2123, Timer_ID=3), (E_T=3234, Timer_ID=10)). b) The value Father(N_B_S)=Father(4)=3/2=1. The value FatherVal(N_B_S).ET=2123. c) Since the value FatherVal(N_B_S).ET=2123 is greater than the value E_B_S.ET=701 and the value Father(N_B_S)=1 is greater than zero, the value FatherLoc(Father(N_B_S)) may be calculated as ¼=0. A read command may be sent to the circuit 126 to read the contents from the address 0. During the 105-th clock cycle: a) The values (P_E_B_S, (E_T=2123, Timer_ID=3))=((E_T=6243, Timer_ID=2), (E_T=2123, Timer_ID=3)) may be written in the circuit 126 at the address Loc(N_B_S)=5/2=2. b) The value TwinVal(Father(N_B_S)) (ET=3234, Timer_ID=10) may be stored in the register P_E_B_S. c) The circuit 126 may present the values ((*,*), (E_T=1234), Timer_ID=5)) to the circuit 122 . The values may be stored in the register R_T_Q. The symbol (*,*) generally means that upper-half entry at the address 0 is not used and may be undefined. d) Set the value N_B_S=Father(N_B_S)=1. During the 106-th clock cycle: a) The register R_T_Q may present the values ((*,*), (E_T=1234), Timer_ID=5)). b) The value Father(N_B_S)=Father(1)=0/2=0. The value FatherVal(N_B_S).ET=1234. c) Since the value FatherVal(N_B_S).ET=1234 is greater than the value E_B_S.ET=701 and the value Father(N_B_S)=0, the values ((0,0), (E_T=701, Timer_ID=11)) may be written in the circuit 126 at the address 0. During the 107-th clock cycle: a) The values ((E_T=1234), Timer_ID=5), (E_T=3234, Timer_ID=10)) may be written in the circuit 126 to the address Loc(N_B_S)=2/2=1. The value BUSY_FLAG is generally set to zero, and the process stopped. Referring to FIG. 5 , a diagram of the circuit 126 after the enqueue process has been performed is shown. A new timer with an expiration time=701 is now at the root of the heap 100 (e.g., address 0). The timer with the expiration time=1234 has been move to the address=1, a row below the new timer. The other times may be re-sorted according to the expiration timer values. The requeue process: The requeue(or bubble-down) process may include the following steps: Step 1. C_MIN generally contains information about timer Step 1a. If the value C_MIN.D=1 (e.g., should-be-deleted condition is true) or the value C_MIN.T indicates a one-shot timer, the timer should be deleted. Therefore, if the value F_S=1, set the values F_S=0, H_S=0 and stop. Otherwise the value BUSY_FLAG may be set to one. The circuit 122 may send a read command to the circuit 126 to read the contents from the address Loc((F_S)−1). If H_S=F_S, set H_S=(HS)−1. The value F_S may be set to (F_S)−1 and the process may continue at step 2. Step 1b. If the value C_MIN.D=0 and C_MIN.T indicates that the timer is periodic, the timer should be requeued. The circuit 122 generally calculates a new expiration time E_T=H_MIN.ET+C_MIN.P for the periodic timer. Set H_MIN.ET=E_T. If the value H_S=1, the process may be stopped. Otherwise, the value BUSY_FLAG may be set to one. The circuit 122 may send a read command to the circuit 126 to acquire the contents from the address 0. Set N_B_S=0 and the process may continue at step 3. Step 2. During a next clock cycle: The circuit 126 generally presents the contents from the address Loc(F_S) to the circuit 122 . The circuit 122 may store the value Val(F_S) to the register H_MIN. The circuit 122 may send a read command to the circuit 126 for the contents from the address 0. Set N_B_S=0 and continue with step 3. Step 3. During a next clock cycle: The circuit 126 generally present the content at the address 0 to the circuit 122 . The circuit 122 may store the received contents to the register R_T_Q. The circuit 122 may send a read command to the circuit 126 to obtain the contents from the address 1. The circuit 122 may also send a read command to the circuit 124 to read the contents from the address H_MIN.ID. Continue with the step 4. Step 4. During a next clock cycle: The register R_T_Q may present the contents read from the circuit 126 at the address 0. If the value H_MIN.ET<Val(0).ET, the contents received from the circuit 124 may be stored to the register C_MIN. Set the value BUSY_FLAG=0 and stop. Otherwise, write the values((0,0), Val(0)) in the circuit 126 at the address 0. The circuit 122 may send a read command to the circuit 124 for the contents from the address Val(0),ID. Set the values E_B_S=H_MIN, H_MIN=Val(0) and P_E_B_S=(0,0). The circuit 126 generally presents the content 10 stored at address 1 to the circuit 122 . The circuit 122 generally stores the received contents to the register R_T_Q. The process may continue at step 5a. Step 5. During a next clock cycle: Step 5a. The contents received by the circuit 122 from the circuit 124 may be stored to the register C_MIN. Step 5b. The contents of the register R_T_Q may be written to the circuit 126 at the address ChildrenLoc(N_B_S). Step 5c. If the values E_B_S.ET≦LeftChildVal(N_B_S).ET and E_B_S.ET≦RigthChildVal(N_B_S).ET, the value BUSY_FLAG may be set to zero and the processes stops. Step 5d. Let M=(LeftChildVal(N_B_S).ET≦RigthChildVal(N_B_S).ET)?LeftChild(N_B_S):RigthChild(N_B_S), (e.g., M may be an index of the child with a minimal expiration time.) The phrase (A≦B)?C:D generally means that if the expression A≦B is true, return the value C, else return the value D. Step 5e. Let L=(LeftChild(M)≧H_S−1)?1:0 (e.g., L=1 only if M is a leaf). Set IS_LEAF=L. Step 5f. If L=1, write the values TwinVal(M) and E_B_S (in correct order) in the circuit 126 at the address ChildrenLoc(N_B_S). If L≠1, the circuit 122 may calculate ChildrenLoc(M) and send a read command to the circuit 126 to retrieve the contents from the address ChildrenLoc(M). Step 5g. Swap the timer being sorted and the minimal child (e.g., set E_B_S=Val(M) and if M is a left child, set E_B_S to the upper-half of R_T_Q, else set E_B_S to the lower-half of R_T_Q.) Step 5h. Set PARENT_ID=N_B_S, N_B_S=M. Step 5i. Continue with step 6. Step 6. During a next clock cycle: The values P_E_B_S and E_B_S (in correct order) may be written in the circuit 126 at the address Loc(PARENT_ID). If IS_LEAF=1, the value BUSY_FLAG may be set to zero and the process may stop. Otherwise, set the values E_B_S=Val(N_B_S) and P_E_D_S=TwinVal(N_B_S). The circuit 126 generally presents the contents at the address ChildrenLoc(N_B_S) to the circuit 122 . The circuit 122 may store the received contents in the register R_T_Q. The process may continue with step 5b. The requeue process generally works using no more than 2×(log 2 ((H_S)−1)−1)+4=2×log 2 ((H_S)−1)+2 clock cycles. Consider an example of application of the requeue process for a case where the value H_MIN.ET=500, H_MIN.ID=4, C_MIN.P=5000, C_MIN.D=0 and BUSY_FLAG=0. The value C_MIN.T may indicate that the timer is a periodic timer. The circuit 126 may be as described in FIG. 3 , (e.g., storing the binary heap 100 described in FIG. 1 ). The current system clock cycle (e.g., value of system timer) may be 500. Since the value H_MIN.ET generally matches the value of system timer, the requeue process may be activated. During the 500-th clock cycle: a) Since the value C_MIN.D=0 and the value C_MIN.T may indicate a periodic timer, a new expiration time E_T=H_MIN.ET+C_MIN.P=500+5000=5500 may be calculated for the periodic timer. Set the value H_MIN.ET=E_T=5500. Set the value BUSY_FLAG=1. Step the value N_B_S=0. A read command may be sent to the circuit 126 to obtain the timer from address 0. During the 501-th clock cycle: a) The circuit 126 generally present a content ((*,*), (E_T=1234), Timer_ID=5)) to the circuit 122 . The circuit 122 generally stores the received content to the register R_T_Q. b) The circuit 122 may send a read command to the circuit 126 for the contents at the address 1. c) The circuit 122 may send a command to the circuit 124 to read from the address H_MIN.ID. During the 502-th clock cycle: a) The register R_T_Q may present the values ((*,*), (E_T=1234), Timer_ID=5)). b) The value H_MIN.ET=5500 is greater than the value Val(0).ET=1234. Therefore, the values ((0,0), (E_T=1234), Timer_ID=5)) may be written into the circuit 126 at the address 0. The circuit 122 may also send a read command to the circuit 124 from the data at the address Val(0),ID=5. The circuit 122 may also set the values E_B_S=H_MIN, H_MIN=Val(0) and P_E_B_S=(0,0). The circuit 126 may present the values ((ET=2123, Timer_ID=3),(ET=3234, Timer_ID=10)) to the circuit 122 . The circuit 122 may store the values in the register R_T_Q. During the 503-th clock cycle: a) The content presented by the circuit 124 to the circuit 122 may be stored in the register C_MIN. b) The register R_T_Q generally presents the values ((E_T=2123, Timer_ID=3), E_T=3234, Timer_ID=10)). c) The value E_B_STET=5500>LeftChildVal(0).ET=2123. Therefore, M=(2123≦3234)?(2*0+1):(2*0+2)=1. d) The value LeftChild(1)=2×1+1=3 is less than the value (H_S)−1=9. Therefore, the value L may be set to zero. The circuit 122 may also set the value IS_LEAF=L=0. e) Since the value L=0, the circuit 122 may calculate ChildrenLoc(1)=2×Loc(1)+1-mod(1)=2×(1+1)/2+1−1=2. The circuit 122 may also send a read command to the circuit 126 to read from the address 2. f) The circuit 122 generally swaps the timer being sorted and the minimal child (e.g., set E_B_S=Val(1)=(E_T=2123, Timer_ID=3) and R_T_Q=((E_T=5500, Timer_ID=4), (E_T=3234, Timer_ID=10)). Set the values PARENT_ID=N_B_S=0 and N_B_S=M=1. During the 504-th clock cycle: a) Write the values ((0,0), (E_T=2123, Timer_ID=3)) in the circuit 126 at the address Loc(0)=0. b) Since IS_LEAF=0, the circuit 122 may set the value E_B_S. Val(1)=(E_T=5500, Timer_ID=4) and the value P_E_B_S=TwinVal(1)=(E_T=3234, Timer_ID=10). c) The circuit 126 may present the values ((E_T=6243, Timer_ID=2), (E_T=4455, Timer_ID=8)) to the circuit 122 . The circuit 122 may store the values to the register R_T_Q. During the 505-th clock cycle: a) The register R_T_Q may present the values ((E_T=6243, Timer_ID=2), (E_T=4455, Timer_ID=8)). b) The value E_B_S.ET=5500 is greater than the value RightChildVal(1).E_T=4455. Therefore, M=(6243≦4455)?(2×1+1):(2×1+2)=4. c) LeftChild(4)=2×4+1=9=(115)−1. Therefore, L=1. The value IS_LEAF=L=1. d) Since L=1, the circuit 122 may write the values ((E_T=6243, Timer_ID=2), (E_T=5500, Timer_ID=4)) in the circuit 126 at the address ChildrenLoc(1)=2. e) Swap the timer being sorted and minimal child (e.g., set E_B_S=Val(4)=(E_T=4455, Timer_ID=8) and R_T_Q=((E_T=6243, Timer_ID=2),(E_T=5500, Timer_ID=4)). f) Set the value PARENT_ID=N_B_S=1, N_B_S=M=4. During the 506-th clock cycle: a) The circuit 122 may write the values ((E_T=4455), Timer_ID=8), (E_T=3234, Timer_ID=10)) in the circuit 126 at the address Loc(1)=1. b) Since IS_LEAF=1, the value BUSY_FLAG may be set to zero, and the process may stop. Referring to FIG. 6 , a diagram of the circuit 126 after the requeue process has been performed is shown. The timer with the expiration time=1234 may be gone from the circuit 126 . The timer with the next closest expiration time=2123 may be moved into the root location at the address 0. The child timer with expiration time 4455 may be moved from the right side of the array at the address 2 into the left side of the array at the address 1. The rest of the timers may be sorted accordingly. The functions performed by the diagrams of FIGS. 2 and 4 may be implemented using one or more of a conventional general purpose processor, digital computer, microprocessor, microcontroller, RISC (reduced instruction set computer) processor, CISC (complex instruction set computer) processor, SIMD (single instruction multiple data) processor, signal processor, central processing unit (CPU), arithmetic logic unit (ALU), video digital signal processor (VDSP) and/or similar computational machines, programmed according to the teachings of the present specification, as will be apparent to those skilled in the relevant art(s). Appropriate software, firmware, coding, routines, instructions, opcodes, microcode, and/or program modules may readily be prepared by skilled programmers based on the teachings of the present disclosure, as will also be apparent to those skilled in the relevant art(s). The software is generally executed from a medium or several media by one or more of the processors of the machine implementation. The present invention may also be implemented by the preparation of ASICs (application specific integrated circuits), Platform ASICs, FPGAs (field programmable gate arrays), PLDs (programmable logic devices), CPLDs (complex programmable logic device), sea-of-gates, RFICs (radio frequency integrated circuits), ASSPs (application specific standard products), one or more monolithic integrated circuits, one or more chips or die arranged as flip-chip modules and/or multi-chip modules or by interconnecting an appropriate network of conventional component circuits, as is described herein, modifications of which will be readily apparent to those skilled in the art(s). The present invention thus may also include a computer product which may be a storage medium or media and/or a transmission medium or media including instructions which may be used to program a machine to perform one or more processes or methods in accordance with the present invention. Execution of instructions contained in the computer product by the machine, along with operations of surrounding circuitry, may transform input data into one or more files on the storage medium and/or one or more output signals representative of a physical object or substance, such as an audio and/or visual depiction. The storage medium may include, but is not limited to, any type of disk including floppy disk, hard drive, magnetic disk, optical disk, CD-ROM, DVD and magneto-optical disks and circuits such as ROMs (read-only memories), RAMS (random access memories), EPROMs (electronically programmable ROMs), EEPROMs (electronically erasable ROMs), UVPROM (ultra-violet erasable ROMs), Flash memory, magnetic cards, optical cards, and/or any type of media suitable for storing electronic instructions. The elements of the invention may form part or all of one or more devices, units, components, systems, machines and/or apparatuses. The devices may include, but are not limited to, servers, workstations, storage array controllers, storage systems, personal computers, laptop computers, notebook computers, palm computers, personal digital assistants, portable electronic devices, battery powered devices, set-top boxes, encoders, decoders, transcoders, compressors, decompressors, pre-processors, post-processors, transmitters, receivers, transceivers, cipher circuits, cellular telephones, digital cameras, positioning and/or navigation systems, medical equipment, heads-up displays, wireless devices, audio recording, storage and/or playback devices, video recording, storage and/or playback devices, game platforms, peripherals and/or multi-chip modules. Those skilled in the relevant art(s) would understand that the elements of the invention may be implemented in other types of devices to meet the criteria of a particular application. As would be apparent to those skilled in the relevant art(s), the signals illustrated in FIG. 2 represent logical data flows. The logical data flows are generally representative of physical data transferred between the respective blocks by, for example, address, data, and control signals and/or busses. The system represented by the circuit 100 may be implemented in hardware, software or a combination of hardware and software according to the teachings of the present disclosure, as would be apparent to those skilled in the relevant art(s). As used herein, the term “simultaneously” is meant to describe events that share some common time period but the term is not meant to be limited to events that begin at the same point in time, end at the same point in time, or have the same duration. While the invention has been particularly shown and described with reference to the preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made without departing from the scope of the invention.

An apparatus having a first memory and a circuit is disclosed. The first memory may be configured to store a plurality of timers. Each of the timers may have a respective value that indicates an expiration time. A first one of the timers nearest to expiring is generally stored at a first address of the first memory. The circuit may be configured to (i) assert a signal in response to the respective value of the first timer matching a counter of time, (ii) read a second of the timers and a third of the timers both from a second address of the first memory, (iii) sort the second timer and the third timer to determine which expires next and (iv) replace the first timer by writing one of the second timer or the third timer that expires next into the first memory at the first address.

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims priority to and the benefit of co-pending U.S. provisional patent application Ser. No. 61/422,330 filed Dec. 13, 2010, which application is incorporated herein by reference in its entirety. STATEMENT REGARDING FEDERALLY FUNDED RESEARCH OR DEVELOPMENT [0002] The invention described herein was made in the performance of work under a NASA contract, and is subject to the provisions of Public Law 96-517 (35 USC 202) in which the Contractor has elected to retain title. FIELD OF THE INVENTION [0003] The invention relates to optical absorbers in general and particularly to optical absorbers that employ carbon nanotubes. BACKGROUND OF THE INVENTION [0004] Novel properties often emerge in low-dimensional nanomaterials, such as polymer-nanorod organic solar cells, graphene, Si nanowires (NWs), and TiO 2 nanoparticles, which can be used to enhance the performance of devices for electronics, energy harvesting, photonics and sensing. Other examples show increased optical absorption efficiency arising from surface plasmon modes in 50-100 nm diameter spherical, metallic nanoparticles on amorphous Si which scatter light more effectively for solar cell applications. [0005] Optical absorption efficiency, an important metric for sensing, radiometric and energy harvesting applications, has been studied theoretically and experimentally in porous, ordered nanostructures, including multi-walled—(MW) carbon nanotubes (CNTs) and single-walled—(SW) CNTs. High-density arrays of CNTs on electrically insulating and nonmetallic substrates have been commonly reported. [0006] There is a need for systems and methods that provide optical absorbers that operate over a wide range of wavelengths and that have high absorptivity, low reflectivity and thermal stability. SUMMARY OF THE INVENTION [0007] According to one aspect, the invention features a monolithic optical absorber. The monolithic optical absorber comprises a conductive substrate having a surface; a template layer in contact with the surface of the conductive substrate, the template layer having a template layer surface; a nucleation layer in contact with the surface of the template layer, the nucleation layer having a nucleation layer surface; and a carbon nanotube array in contact with the nucleation layer surface, the carbon nanotube array having a plurality of mutually aligned nanotubes with a site density of at least 1×10 9 nanotubes/cm 2 . [0008] In one embodiment, the conductive substrate is a silicon wafer. [0009] In another embodiment, the conductive substrate is a metal. [0010] In yet another embodiment, the template layer comprises a refractory nitride. [0011] In still another embodiment, the template layer comprises NbTiN. [0012] In a further embodiment, the nucleation layer comprises Co and Ti. [0013] In yet a further embodiment, the monolithic optical absorber has a reflectivity of less than 1%. [0014] In still a further embodiment, the monolithic optical absorber absorbs radiation in the wavelength range of 350 nm to 7000 nm. [0015] In another embodiment, the monolithic optical absorber absorbs radiation in the wavelength range of 350 nm to 200,000 nm. [0016] According to another aspect, the invention relates to a method of manufacturing a monolithic optical absorber. The method comprises the steps of: providing a conductive substrate having a surface; depositing on the surface of the conductive substrate a template layer having a template layer surface; depositing on the surface of the template layer a nucleation layer having a nucleation layer surface; and using a plasma deposition method, growing a plurality of mutually aligned carbon nanotubes on the surface of the nucleation layer. [0017] In one embodiment, the plasma deposition method is a plasma-assisted chemical vapor deposition method. [0018] In another embodiment, the plasma deposition method includes the use of an electric field. [0019] In yet another embodiment, an orientation of a length of the carbon nanotube array having a plurality of mutually aligned nanotubes relative to the surface of the conductive substrate is controlled by controlling an orientation of the electric field relative to the surface of the conductive substrate during the growing step. [0020] In still another embodiment, the conductive substrate is a silicon wafer. [0021] In a further embodiment, the conductive substrate is a metal. [0022] In yet a further embodiment, the template layer comprises a refractory nitride. [0023] In an additional embodiment, the template layer comprises NbTiN. [0024] In one more embodiment, the nucleation layer comprises Co and Ti. [0025] In still a further embodiment, a thickness of the nucleation layer is adjusted. [0026] In yet another embodiment, the carbon nanotube array having a plurality of mutually aligned nanotubes has a site density in the range of 1×10 9 nanotubes/cm 2 to 1×10 12 nanotubes/cm 2 . [0027] The foregoing and other objects, aspects, features, and advantages of the invention will become more apparent from the following description and from the claims. BRIEF DESCRIPTION OF THE DRAWINGS [0028] The objects and features of the invention can be better understood with reference to the drawings described below, and the claims. The drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention. In the drawings, like numerals are used to indicate like parts throughout the various views. [0029] FIG. 1 is an SEM micrograph of a Co/Ti/Si sample after DC PECVD growth. All SEMs were taken at a 30° viewing angle. [0030] FIG. 2 is an optical image of the sample of FIG. 1 showing a reflective surface. [0031] FIG. 3 is a diagram illustrating a vertical cross-section through the through the structure on which the sample of FIG. 1 was grown. [0032] FIG. 4 is an SEM micrograph of a Co/Ti/NbTiN sample after growth, showing a high density carpet of MWCNTs. [0033] FIG. 5 is an optical image of the sample of FIG. 4 that appears as a visually black sample to the naked eye. The spatial uniformity of the MWCNT ensembles is high over large length scales. [0034] FIG. 6 is a diagram illustrating a vertical cross-section through the structure on which the sample of FIG. 4 was grown. [0035] FIG. 7 is a high magnification SEM image that shows the porous, vertically aligned morphology of the CNT absorbers, in contrast to the reference benchmark Au-black absorber sample in FIG. 8 . [0036] FIG. 8 is a high magnification SEM image that shows a percolated, randomly aligned network of fibers. [0037] FIG. 9 is a graph illustrating the results of reflectance measurements from λ˜350 nm-2500 nm for the MWCNT absorber and a Au-black absorber reference sample. The Au-black reference sample has R˜100× larger where R˜0.02% for the CNT sample compared to 1.1% for the Au-black at λ˜2000 nm. [0038] FIG. 10 is a diagram that illustrates a measurement set-up. [0039] FIG. 11 is a graph showing optical reflectance spectra taken for two samples with Co catalyst thicknesses c˜0.9 nm and 5 nm. Superimposed on the reflectance vs. wavelength data are theoretical fits from which the ratio of κ at c˜0.9 nm and 0.5 nm was determined. [0040] FIG. 12 shows the variation of the thickness l of the absorber with Co catalyst thickness c. [0041] FIG. 13 is a diagram that illustrates the geometry used for the optical modeling analysis. [0042] FIG. 14 illustrates the morphology of the MWCNTs for c˜0.9 nm, showing thin, vertically aligned CNTs are depicted that have a high fill fraction with a site density of ˜4×10 11 /cm 2 and MWCNT diameters ˜10-15 nm. The growth conditions for the MWCNTs illustrated in FIG. 14 , FIG. 15 and FIG. 16 were: 750° C., 172 W of plasma power, 30% C 2 H 2, 5 Torr. [0043] FIG. 15 illustrates the morphology of the MWCNTs for c˜2 nm. [0044] FIG. 16 illustrates the morphology of the MWCNTs for c˜5 nm, showing a site density of ˜6×10 9 /cm 2 with MWCNT diameters ˜80-100 nm. [0045] FIG. 17 is a graph showing the results of reflectance measurements as a function of c (taken at λ˜1500 nm) for two acetylene gas ratios (30% and 23%). [0046] FIG. 18 is a graph that shows the results of total hemispherical reflectance measurements made from λ˜250 nm-2000 nm. The measurements reveal R T ˜1.8% at 1000 nm. [0047] FIG. 19 shows a schematic of the total hemispherical reflectance measurement set-up. [0048] FIG. 20 illustrates the results of long-wavelength IR measurements, which yields reflectance R˜2.4% for the sample with c˜0.9 nm, while R˜14.7% for c˜5 nm at λ˜7000 nm. Superimposed are theoretical fits to the data for c˜0.9 nm and 5 nm, using an expression of the form R(λ)=R o exp(−α/λ) where α is the absorption coefficient. The undulations in the reflectance are possibly due to interference effects from the substrate. The growth conditions were 750° C., 170 W of plasma power, 30% C 2 H 2, and 5 Torr. [0049] FIG. 21 is a graph that shows the angular dependence of reflectance R where R is fairly low (less than ˜2%) up to 50°, and an increase up to ˜10% is seen at 70°. [0050] FIG. 22 is a graph that shows the variation of R with specular angle of incidence, assuming TE and TM polarized-modes of radiation. While a polarization-sensitive study can yield additional insights, an absolute minimum in the TM mode at 72° can be used to further suppress R to enhance absorption. [0051] FIG. 23 is an SEM image of an Au-black absorber sample at 25° C. [0052] FIG. 24 is an SEM image of the Au-black absorber after heating to 200° C. for 1 hour in air. After heating to 200° C., the percolated structure of the Au-black absorber sample appears to fragment. [0053] FIG. 25 is an SEM image of the Au-black absorber after heating to 400° C. for 1 hour in air. After heating to 400° C. the structure collapses completely as the filaments coarsen. [0054] FIG. 26 is an SEM image of a MWCNT absorber sample at 25° C. [0055] FIG. 27 is an SEM image of the MWCNT absorber sample after heating to 200° C. [0056] FIG. 28 is an SEM image of the MWCNT absorber sample after heating to 400° C. The MWCNT absorbers have a high structural integrity since no change in morphology is detected after heating to 200° C. and 400° C. [0057] FIG. 29 is a graph showing the results of reflectance measurements of the Au-black and CNT absorber samples as a function of temperature. The Au-black absorber shows R increasing up to 23% after heating to 400° C., while the CNT absorber shows essentially R=0 versus temperature using the same vertical axis. [0058] FIG. 30 is a graph showing the results of reflectance R measurements of the CNT sample versus temperature using a higher resolution on the vertical axis. R increases slightly after exposure to 200° C. but it is still very low (R˜0.022% at λ˜2000 nm) and remains unchanged after exposure to temperatures as high as ˜400° C. [0059] FIG. 31 is a schematic diagram that illustrates the alignment of a plurality of CNTs that are grown using an electric field that is varied in discrete steps. [0060] FIG. 32 is a schematic diagram that illustrates the alignment of a plurality of CNTs that are grown using an electric field that is varied continuously. DETAILED DESCRIPTION [0061] We describe a nanomaterial-based monolithic optical absorber which offers exceptional light-trapping capabilities as a result of its unique physical structure comprised of high-density, porous arrays of thin (10-15 nm diameter), vertically oriented MWCNTs. This monolithic optical absorber provides an optical-to-thermal transduction mechanism that offers a broad spectrum of applications, ranging from energy harnessing, high sensitivity thermal detectors, radiative cooling, thermography, antireflection coatings and optical baffles to reduce scattering. In some embodiments, the monolithic optical absorbers can be used with thermo-electric converters, for example, thermo-electric converters situated on a roof-top where solar energy is trapped by the absorbers and the thermo-electric converts this thermal energy to electricity. The monolithic optical absorbers have been demonstrated to be unaffected by high temperatures up to at least 400° C., which allows their application in environments where elevated temperatures are expected. [0062] We have fabricated vertically aligned MWCNT arrays with CNT site densities greater than 1×10 11 nanotubes/cm 2 synthesized directly on conductive substrates (e.g., doped semiconductor substrates or metallic substrates) using a plasma-enhanced (PE) chemical vapor deposition (CVD) process and have characterized the absorption efficiencies of the arrays in the 350 nm-7000 nm wavelength range, spanning the range from the ultraviolet (UV) to the infra-red (IR) for the first time. It is expected that this range can be much broader, for example from 350 nm into the far-IR range, up to 200,000 nm or 200 μm (microns). It is expected that applications of these absorbers will include broad-band detectors (both cooled or uncooled) that can operate into the far-IR range. It is believed that one can tune the absorption to longer wavelengths beyond 7000 nm by tuning the length of the CNTs (e.g., up to hundreds of microns) so the length is comparable to the wavelength of the incoming radiation. In practice, the length would be controlled by the growth time during PECVD synthesis. The LWIR, mid-IR and far-IR range are important windows for applications because there is a lack of suitable black coatings at these longer wavelengths. [0063] In the past, using conventional thermal CVD deposition, achieving high site-densities on metals has been challenging, because site-densities on metals are reduced many-fold due to the challenges in stabilizing catalyst nanoparticles on metallic surfaces at high temperatures. Our ultra-thin absorbers exhibit a reflectance as low as ˜0.02% (100 times lower than the benchmark) which has the potential to increase sensitivity and speed of thermal detectors in focal plane arrays. The present results increase the portfolio of materials that can be integrated with such absorbers due to the potential for reduced synthesis temperatures arising from a plasma process. A phenomenological model enabled us to determine the extinction coefficients in these nanostructures and we have also demonstrated their remarkable immunity to high temperatures, which is advantageous for solar-cell applications. [0064] It is believed that the orientation of the CNTs relative to the surface of the conductive substrate is defined by the relative orientation of the applied electric field and the surface of the conductive substrate as the growth of the CNTs proceeds. Therefore, it is believed that CNTs (and CNT arrays) having controlled orientation along the length of the CNTs can be fabricated by controlling the relative orientation of the applied electric field and the surface of the conductive substrate. For example, it is expected that CNTs and CNT arrays having deliberately introduced “bends” or changes in orientation along the length of the CNTs can be fabricated by changing the relative orientation of the applied electric field and the surface of the conductive substrate during the growth process. [0065] Previously synthesized MWCNTs and SWCNTs for optical absorber applications used water-assisted thermal CVD, which yields exceptionally high growth rates with CNT lengths greater than hundreds of microns, where alignment is believed to occur primarily via the crowding effect. While thermal CVD is generally considered ineffective in aligning short CNTs (CNTs having length<10 μm), we have demonstrated that growth of nanotubes using a glow discharge (PECVD) growth method produces vertically aligned CNTs with lengths more than an order of magnitude shorter, which nonetheless still yield broadband, high-efficiency optical absorption characteristics in the UV-to-IR range. This work also extends the previously reported measurements on MWCNTs that were conducted in the visible, to well into the IR regime where it is increasingly difficult to find suitable black/opaque coatings. A thin and yet highly absorbing coating with absorptance A is valuable for thermal detector applications in the IR for radiometry in order to enhance sensitivity, since the detectivity D*∝A. Besides sensitivity, a thinner absorber yields high detector speeds since the thermal response time [0000] τ th = C th G , [0000] where C th is the heat capacity (J/K) of the absorber, G is the thermal conductance (W/K) and C th ∝a*l where a and l are the area and thickness of the absorber; thus a greater than 10 times reduction in l increases the detector speed by greater than 10 times. [0066] The other structural trait for enhancing optical absorption efficiency is a high site density, e.g., a high density of nanotubes per unit area. Unlike earlier reports where the CNTs were synthesized directly on Si or SiO 2 we have demonstrated growth of high-efficiency MWCNT absorbers directly on metallic substrates with site densities as high as ˜4×10 11 nanotubes/cm 2 . In many other applications, it is desirable to grow CNTs directly on metals for lowering contact resistance but the challenges in stabilizing catalyst particles on metallic surfaces at high temperatures have generally reduced site densities of CNTs many fold (up to 100×). In addition, prior attempts at growing MWCNTs for optical absorber applications on substrates other than Si, such as LiNbO 3 yielded an absorption efficiency of ˜85% from λ˜600 nm to λ˜1800 nm, whereas the CNT absorbers synthesized here on metallic substrates are shown to have an absorption efficiency greater than 99.98% from λ˜350 nm to λ˜2500 nm. Even cermet-based materials, currently used for solar selective coatings on metallic substrates such as Cu and Al, have absorption efficiencies that are several orders of magnitude (up to 10 4 times) lower than that reported here. We also have demonstrated for the first time that the MWCNT absorbers are exceptionally rugged and exhibit a negligible change in absorption when exposed to temperatures as high as 400° C. in an oxidizing environment, in contrast to the benchmark Au-black, a commonly used black-body reference material, which degrades under the same thermal treatment. Additionally, a plasma-based process increases the potential of forming these absorbers at lower synthesis temperatures compared to thermal CVD, increasing future prospects of integrating such absorbers with a wider range of materials such as low-cost, flexible substrates for solar-cells, solar thermal collectors, or with thermoelectrics, as well as integrated with fragile, temperature-sensitive micro-machined structures used for IR sensing. [0067] The choice of the template for PECVD synthesis of our MWCNTs was important in synthesizing a high-density array of CNTs. We have observed that the template can directly impact the optical absorption characteristics. For example, the scanning-electron-microscope (SEM) image in FIG. 1 shows amorphous carbon deposits when Co/Ti was placed directly on Si at 750° C., exhibiting a largely reflective surface ( FIG. 2 ). On the other hand, using a Co/Ti/NbTiN template yielded a visually black sample to the naked eye ( FIG. 5 ), and the SEM image ( FIG. 4 ) depicts a high-density array of MWCNTs which traps incoming light and suppresses reflection. [0068] FIG. 6 is a diagram illustrating a vertical cross-section through the structure on which the sample of FIG. 4 was grown. As illustrated in FIG. 6 , the structure includes a conductive substrate (the silicon wafer), a template layer (the NbTiN layer), and a nucleation layer or catalyst layer (the Ti/Co layers taken together), upon which the MWCNTs are grown to form a monolithic structure. The lack of growth of MWCNTs on Co/Ti/Si templates ( FIG. 1 ) suggests that the presence of a refractory metallic nitride, such as NbTiN is important in stabilizing the catalyst nanoparticle to prevent diffusion and alloying of the catalyst with the underlying Si at high temperatures. In addition, the density of MWCNTs in the absence of the Ti layer on the Co/NbTiN templates was low. It is speculated that the Ti may enable the Co to fragment into nanoparticles, similar to the role of Mo in the Co—Mo bi-metallic catalyst system. The Ti—Co system also appears to incorporate a larger fraction of C compared to Co alone, enhancing CNT growth. Besides being of interest as absorbers in solar photo-thermal applications, the high areal density of MWCNTs on reflective, low resistivity (˜110 μΩ-cm) metallic substrates may substantially reduce the CNT-to-substrate contact resistance. The high magnification image in FIG. 7 shows the surface of the MWCNTs arrays is rough, a factor which also contributes to scattering the incoming light diffusively. Shown in FIG. 8 is the SEM image of our benchmark, a Au-black absorber, which was synthesized using approaches similar to prior reports; the percolated, random network of such a diffuse metal-black should be apparent. [0069] The optical reflectance response of the CNT absorber is shown in FIG. 9 , where the spectrum is compared to that of a reference Au-black absorber. The reflectance R of the CNT absorber is nearly two orders of magnitude lower than that of the Au-black, e.g., ˜0.02% at λ˜2000 nm compared to 1.1% for Au-black. Other commonly used absorbers, such as NiP have higher R˜0.5-1% for λ˜320-2140 nm, while ultra-black NiP alloy has R˜0.16-0.18% from λ˜488-1500 nm, and black paint has R greater than 2.5% from λ˜600-1600 nm. Top-down synthesized Si nanotips exhibit R˜0.09% at λ˜1000 nm, while bottom-up synthesized nanocone arrays have been reported to have an absorption efficiency of ˜93% from λ˜400-650 nm. [0070] The catalyst thickness appears to be an important synthesis parameter that impacted the optical absorption efficiency in these carbon-based nanoabsorbers. Shown in FIG. 11 are reflectance spectra taken for two samples synthesized at Co catalyst thicknesses c˜5 nm and 0.9 nm (with the Ti thickness fixed at 2.5 nm). The sample with c˜0.9 nm has a wavelength independent response from λ˜350 nm-2500 nm with R in the 0.02-0.03% range. The sample with c˜5 nm, synthesized at identical conditions, has a wavelength dependent R which decreased from 0.94% at λ˜400 nm to ˜0.33% at λ˜2000 nm. Tentatively, the decreased reflectance/increased absorption may be expressed through an exponential decrease of the transmitted intensity I(x) following a simple Lambert-Beer law formulation, i.e., I(x)=I o exp(−αx), where I o is the initial intensity of the incoming light and α is the absorption coefficient. The schematic in FIG. 13 shows the geometry of the optical interrogation system, as the incoming light traverses through the sparse forest of CNTs with intensity I(x) at any vertical location inside the CNT array. The typical absorption coefficient with α˜10 4 cm −1 for I(x=8 μm) is approximately 30 times that for I(x=4.5 μm). Now, the reflectance seems to decrease to the same order, i.e., on the average R drops from ˜0.94 to ˜0.03, approximately 30 times as well. The SEM images of the samples with c˜0.9 nm and 5 nm are shown in FIG. 14 , FIG. 15 and FIG. 16 , respectively. This yielded a MWCNT site density of ˜4×10 11 nanotubes/cm 2 with MWCNT diameters d˜10-15 nm for c˜0.9, and a site density of ˜6×10 9 nanotubes/cm 2 with d˜80-100 nm for c˜5 nm. It is expected that site densities of carbon nanotubes in the range of 1×10 9 nanotubes/cm 2 to 1×10 12 nanotubes/cm 2 can be fabricated using the described methods. Although the length l of the MWCNTs decreased as c increased ( FIG. 12 ), with c˜5 nm, l was still >5 μm, well above λ in these measurements, suggesting that the reduced absorption from the thicker catalyst is likely a result of changes in the fill fraction. The ability to engineer optical absorption efficiency by controlling the catalyst thickness is an attractive feature in tuning the optical absorption properties of the MWCNT ensembles. [0071] One mechanism by which porous objects suppress reflection is through a reduction in the effective refractive index n. However, porosity alone may not necessarily be the primary factor involved since the Au-black absorber samples, a largely porous structure (see SEM in FIG. 8 ) had higher reflectance compared to the MWCNT samples. This enhanced absorption may arise from the weak coupling of electrons in the vertically oriented CNTs to the incoming, normally-incident radiation, with minimal back-scattering and enables light to propagate into the long pores within the arrays until it is finally absorbed. A phenomenological model for absorption was developed using a formulation where the ensembles are treated as a composite medium consisting of nanostructures and air. The intensity at any given point x in FIG. 13 is given by I(x)=I o exp(−αx), where [0000] α = 4  π   κ λ [0000] and κ is the extinction coefficient. Assuming that there is no effective transmission through the substrate, R(x)˜(I o −I(x)). The corresponding variation of R with λ was then fit to the approximate expression [0000] a 1   a 2 λ + a 3 [0000] where a 1 is related to the incident intensity I o , a 2 is a measure of the optical absorption length (=κl) and a 3 is a constant. The fit to the data is shown in FIG. 11 for c˜0.9 nm and 5 nm. From the fits, the value of a 2 was determined to be ˜0.025 and ˜0.026 for c˜0.9 nm and 5 nm, respectively, and given that the ratio, [0000] ( a 2 ) 0.9 ( a 2 ) 5 = ( κ · l ) 0.9 ( κ · l ) 5 [0000] and that l is 8 μm and 5 μm, respectively, we obtain a ratio of the extinction coefficients, [0000] κ 0.9 κ 5   of  ∼ 0.6 . [0072] We rationalize such a value by appealing to the relationship of the complex refractive index, Ñ(=n+iκ) to the dielectric constant, √{square root over ({tilde over (ε)} (where, {tilde over (ε)}=ε 1 +ε 2 ). It can then be derived that when absorption dominates, κ is proportional to √{square root over ({tilde over (ε)}. Using a simple rule of mixtures, the dielectric constant of the air-CNT mixture, {tilde over (ε)}=α·ε CNT +β·ε air , where α and β are the fractions of the CNT and air, respectively, i.e., α+β=1). For the observed MWCNT site density of ˜4×10 11 /cm 2 for c˜0.9 nm, an average area per MWCNT is determined to be approximately 250 nm 2 . Now, with an average d˜10 nm, the area fraction α is approximately 0.31, where it is assumed that all the MWCNTs are perpendicular to the incident radiation. For the samples with c˜5 nm, site density ˜6×10 9 /cm 2 and average d˜100 nm, the corresponding average area per MWCNT is ˜0.16×10 4 nm 2 , and α is ˜0.47. We use an average dielectric constant, {tilde over (ε)} of ˜23 for the CNTs over λ=350-3100 nm, extrapolated from the values of the complex refractive index of graphite at λ˜350 nm and 3100 nm, respectively. Since κ˜√{square root over ({tilde over (ε)} we compute the ratio [0000] κ 0.9 κ 5 ∼ ( ( 0.31 · 23 ) + ( 0.69 · 1 ) ( 0.47 · 23 ) + ( 0.53 · 1 ) ∼ 0.8 . [0000] The value of the [0000] κ 0.9 κ 5 [0000] ratio is then found to be quite close to the value obtained by the fitting shown in FIG. 11 . [0073] It is interesting that the extinction ratio is smaller for the MWCNTs grown with c˜0.9 nm compared to the CNTs grown with c˜5 nm. This observation can be rationalized on the basis of a smaller area fraction in the former case, i.e., 0.31 vs. 0.47. While such a rationalization does not explicitly consider the volume absorption due to a larger l in the former case (i.e., 8 μm vs. 5 μm), it is justified since it has previously been shown that for the case of absorption in Si nanowires the absorption in a thin film over a wide energy range comparable to the one used here, is on the average equivalent to the absorption in the nanowires. The larger absolute magnitude of R for the sample with c˜5 nm compared to the sample with c˜0.9 nm may indicate an influence of the substrate in the latter, the effect of which is more pronounced due to a shorter l for c˜5 nm. [0074] A more detailed analysis of the impact of catalyst thickness on the optical reflectance properties of the MWCNT absorbers was conducted for a wide range of catalyst thicknesses ( FIG. 17 ). This data (at λ˜1500 nm) shows a minimum in the reflectance R at c˜1 nm. However, it is thought that R increases when c˜0.6 nm due to the inability to nucleate a high enough areal density of MWCNTs; such behavior was consistent for two different acetylene gas concentrations, as indicated. [0075] The data for the total reflectance R T of the CNT samples indicates an R T ˜1.8% at λ˜1000 nm as shown in FIG. 18 . These measurements were obtained using an integrating sphere as shown schematically in FIG. 19 . This is more than four times lower than top-down synthesized Si nanotips with an R T ˜8% at λ˜1000 nm. In addition, R T of our samples is 0.8% at λ˜400 nm, in contrast to Si nanostructured films which have R T ˜1.46% in the range of λ˜300-600 nm. Optical reflectance measurements on the CNT absorbers were also extended to the longer IR wavelengths, where it is increasingly difficult to find highly efficient optically black coatings. FIG. 20 shows the specular reflectance, measured using a Harrick 30° specular reflectance attachment, for samples with c˜0.9 nm and 1.6 nm. Again, the specular reflectance for samples with the thinner catalyst c˜0.9 nm was much lower (˜2.4%) than CNTs grown with c˜1.6 nm (˜14.7%) at λ˜7000 nm, and confirms the highly absorbing characteristic of these absorbers at long IR wavelengths. The angular dependence of the specular reflectance was also measured in the range of 30° to 70°, as shown in FIG. 21 (taken at λ˜2500 nm). Although the intensity of the specular reflectance increases with incident angle, the change is relatively small. In comparison, other anti-reflection thin film coatings suppress reflection over a narrow band of angles and have selective absorption characteristics over a narrow spectral range. [0076] Modeling analysis was also pursued at longer wavelengths (>2500 nm) where the increase in R was fit to an expression of the form, R(λ)=R o exp(−α/λ) and the fits to the data are shown in FIG. 20 . It was found from the fits that the value of α for c˜0.9 nm and 5 nm was ˜12560 nm and ˜6850 nm, respectively. From the ratio [0000] ( α ) 0.9 ( α ) 5 = ( κ · l ) 0.9 ( κ · l ) 5 [0000] we deduce a [0000] κ 0.9 κ 5 [0000] value of ˜0.4, which is again close to the previously determined ratio. The angular dependence of R can be modeled by assuming that the incident radiation is predominantly Transverse Electric (TE) polarized. Experimentally, it is possible that the beam is more polarized in one mode than the other but more thorough measurements would need to be conducted to quantify this more accurately. It was seen from FIG. 22 , that R increases with angle, as seen for the TE polarization and also that the absolute magnitude of R increases with λ, confirming experimental observations. It is expected that polarization-sensitive measurements will be undertaken, for example with the Transverse Magnetic (TM) optical mode as well, where the E-field is along the axis of the CNTs, where greater absorption is expected. This would yield a minimum in R at a specific angle, for example at ˜72° with λ=350 nm as shown in FIG. 22 , which may be used in further reducing the reflectance. [0077] We now present data which demonstrates the exceptionally low R of the MWCNT absorbers even after they were exposed to temperatures as high as 400° C. in air under an oxidizing environment, as might be expected with incident solar radiation, for example in a concentrator geometry application. In comparison, the structural characteristics of the Au-black absorber reference gradually deteriorate with increasing temperature as indicated through the SEM images of FIG. 23 through FIG. 25 . However, the structural characteristics of the MWCNT absorber samples are largely unchanged when heated from 25° C. ( FIG. 26 ), to 200° C. ( FIG. 27 ) and to 400° C. ( FIG. 28 ). From the corresponding optical spectra ( FIG. 29 ) it is apparent that R of the Au-black absorber sample increases as it is heated from 25° C. to 200° C. (2%) and is ˜23% at 400° C. (at λ˜2000 nm). On the other hand, the R of the CNT absorbers is still very low, ˜0.022% after heating to 200° C. ( FIG. 30 ), and remains unchanged after exposure to temperatures as high as 400° C. which can be correlated to the structural integrity of the CNT absorbers to temperatures as high as 400° C. ( FIG. 28 ). [0078] In conclusion, we have successfully shown that, through catalyst engineering, PECVD synthesized MWCNTs yield a high site-density on metallic substrates which exhibit ultra-low reflectance (˜0.02%) over a wide spectral range from UV-to-IR for relatively thin (less than 10 μm) absorber ensembles. Their highly-efficient optical absorption properties and exceptional ruggedness at high temperatures suggests their promise in solar photo-thermal applications and IR thermal detectors for radiometry applications. In addition, the use of a plasma-based process increases the potential for synthesizing the absorbers at lower temperatures in the future, increasing the likelihood of integrating the absorbers with low-cost flexible substrates, potentially for solar-cell applications, as well as thermoelectrics and micro-machined structures for enabling new classes of IR sensors, particularly for rugged environments. Synthesis of Nanostructures [0079] The initial substrate for the synthesis of the MWCNTs was a <100> oriented Si wafer on which a layer of 100-200 nm thick refractory, high temperature conducting nitride (NbTiN) was deposited reactively in a N 2 and Ar ambient using DC magnetron sputtering at a power of ˜220 W and 5 mTorr. Bi-metallic layers of Co (thickness range 0.6 nm-6 nm) and 2.5 nm thick Ti were e-beam evaporated and served as the catalyst. Beside the Co/Ti/NbTiN/Si templates, control samples of Co/Ti/Si, Co/NbTiN/Si and Co/Si were also prepared. Multiple samples (area ˜4 cm 2 ) were placed on a wafer during PECVD growth so that comparative analysis could be performed for different combinations of templates under similar synthesis conditions. At temperatures in the range of 550 to 750° C., H 2 was flowed into the chamber for several minutes, and the growth gases acetylene (C 2 H 2 ) and ammonia (NH 3 ) were then introduced to a typical pressure of ˜5 Torr and the discharge was then ignited. [0080] It is expected that CNTs having controlled morphology can also be fabricated by growing the CNTs under conditions in which the direction of the electric field is deliberately controlled. The CNTs shown in FIG. 4 and FIG. 7 were prepared using an applied electric field that was oriented normal to the plane of the substrate during the entire PECVD growth process. As illustrated in FIG. 31 and FIG. 32 , the electric field orientation relative to the substrate is varied during the PECVD growth process. In some embodiments, a carbon nanotube array having a plurality of mutually aligned nanotubes can be grown using the methods illustrated by FIG. 31 for one portion of the growth and using the methods illustrated by FIG. 32 for another portion of the growth. It is expected that the orientation of a length of a carbon nanotube array having a plurality of mutually aligned nanotubes relative to the surface of the conductive substrate will be controlled by controlling an orientation of the electric field relative to the surface of the conductive substrate during the growth process. It is expected that the optical properties of the CNT array can be tuned depending on the CNT morphology, or depending on the orientation of the CNT array relative to the propagation direction of the illumination that falls on the array. Absorbers prepared using the directed electric fields as illustrated in either or both of FIG. 31 and FIG. 32 are expected be used as polarizers where one polarization is selectively preferentially absorbed, e.g., if the CNTs are tilted by 45 degrees, it is expected that there would be different absorption of different polarizations of incoming light. [0081] FIG. 31 is a schematic diagram that illustrates the alignment of a plurality of CNTs 3110 that are grown using an electric field that is varied in discrete steps. The CNTs 3110 have substantially aligned (or parallel) orientation in segments grown under the same conditions. In the embodiment shown in FIG. 31 , an electric field is oriented in a plurality of linear piecewise orientations relative to a substrate. At the start of the growth process, the electric field is applied using orientations that can be described as being aligned along a sawtooth function relative to the surface of the substrate (that is, the electric field is tilted at one angle relative to a normal to the surface for a period of growth, and then is tipped at a different angle, such as the opposite angle relative to a normal to the surface of the substrate, for a following period of growth. In the embodiment of FIG. 31 , the final portion of the CNT array is grown using an electric field that is normal to the surface of the substrate, and the CNTs that are grown during that period of growth are perpendicular to the surface of the substrate. As will be recognized, the tilt angle at any time can be selected over a range of angles, such as +45° to −45° in some plane perpendicular to the surface of the substrate. In addition, the plane in which the tilt angle is measured can also be rotated. In other word, the electric field can be applied along discrete orientations, such as along lines defined in the surface of a cone described about a normal to the substrate surface, rather than simply at angles defined in a single plane. [0082] FIG. 32 is a schematic diagram that illustrates the alignment of a plurality of CNTs 3210 that are grown using an electric field that is varied continuously. The CNTs 3210 have substantially aligned orientation in segments grown under the same conditions. In the embodiment illustrated in FIG. 32 , the electric field orientation relative to the surface of the substrate is varied in a sinusoidal manner. The CNTs that are grown have a sinusoidal morphology. It should be apparent that if the orientation of the electric field is varied both in angular measure relative to a normal to the surface of the substrate, and can also be rotated around a normal to the surface of the substrate, CNTs that have curvilinear structure, such as a corkscrew, are expected to be produced. Optical Measurement Using Fieldspec Pro Spectroradiometer [0083] The optical measurements on the samples were conducted from λ˜350 nm to 2500 nm using a high resolution, fiber coupled, spectroradiometer (Fieldspec Pro available from ASD Inc., 2555 55th Street, Suite 100, Boulder, Colo. 80301) where a standard white light beam was shone at normal incidence to the sample, as shown by the schematic in FIG. 10 . The bare fiber connector of the spectroradiometer was oriented at ˜40° from the normal. Relative reflectance spectra were obtained by first white referencing the spectroradiometer to a 99.99% reflective Spectralon™ panel. The reflected light intensity from the sample was then measured and the spectra compared for samples synthesized under different growth conditions. Total Reflectance Measurement Using the Integrating Sphere [0084] The total reflectance of the CNT absorbers was measured using a 110 mm diameter integrating sphere with the Varian/Cary Diffuse Reflectance accessory, available from Agilent Technologies, 5301 Stevens Creek Blvd, Santa Clara Calif. 95051 (schematic shown in FIG. 19 ). The reflectance was normalized to the response obtained from a Spectralon™ PTFE standard coating (reflectance>99.99%) under identical conditions. Spectralon™ PTFE standard coating is available from Labsphere, Inc. Theoretical Discussion [0085] Although the theoretical description given herein is thought to be correct, the operation of the devices described and claimed herein does not depend upon the accuracy or validity of the theoretical description. That is, later theoretical developments that may explain the observed results on a basis different from the theory presented herein will not detract from the inventions described herein. [0086] Any patent, patent application, or publication identified in the specification is hereby incorporated by reference herein in its entirety. Any material, or portion thereof, that is said to be incorporated by reference herein, but which conflicts with existing definitions, statements, or other disclosure material explicitly set forth herein is only incorporated to the extent that no conflict arises between that incorporated material and the present disclosure material. In the event of a conflict, the conflict is to be resolved in favor of the present disclosure as the preferred disclosure. REFERENCES [0000] L. Hu and G. Chen, Nano Lett. 7, 3249 (2007). K. Peng, Y. Wu, H. Fang, X. Zhong, Y. Xu, and J. Zhu, Angew. Chem. Int. Ed. 44, 2737 (2005). Z-P. Yang, L. Ci, J. A. Bur, S-Y. Lin, and P. M. Ajayan, Nano Lett. 8, 446 (2008). K. Mizuno, J. Ishii, H. Kishida, Y. Hayamizu, S. Yasuda, D. N. Futaba, M. Yumura, and K. Hata, Proc. Natl. Acad. Sci. U.S.A. 106, 6044 (2009). Z. F. Ren, Z. P. Huang, J. W. Xu, J. H. Wang, P. Bush, M. P. Siegal, and P. N. Provencio, Science 282, 1105 (1998). K. Hata, D. N. Futaba. K. Mizuno, T. Namai, M. Yumura, S. Iijima, Science 306, 1362 (2004). T. Yamada, T. Namai, K. Haa, D. N. Futaba, K. Mizuno, J. Fan, M. Yudasaka, M. Yumura, S. Iijima, Nat. Nanotechnol. 1, 131 (2006). G. D. Nessim, A. J. Hart, J. S. Kim, D. Acquaviva, J. M. Oh, C. D. Morgan, M. Seita, J. S. Leib, and C. V. Thompson, Nano Lett. 8, 3587-3593 (2008). J. Weickert, R. B. Dunbar, H. C. Hesse, W. Wiedemann, and L. Schmidt-Mende, Adv. Materials 23, 1810 (2011). R. R. Nair, P. Blake, A. N. Grigorenko, K. S. Novoselov, T. J. Booth, T. Stauber, N. M. R. Peres, and A. K. Geim, Science 320, 1308 (2008). X. Yan, X. Cui, B. Li, and L-shi Li, Nano Lett. 10, 1869 (2010). B. M. Kayes, H. A. 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Johnson, Metal Finish. 78, 21 (1980). S. Kodama, M. Horiuchi, T. Kuni, and K. Kuroda, IEEE Trans. Inst. and Meas. 39, 230 (1990). C. Lee, S. Bae, S. Mobasser, and H. Manohara, Nano Lett. 5, 2438 (2005). J. Zhu, Z. Yu, G. F. Burkhard, C.-M Hsu, S. T. Connor, Y. Xu, Q. Wang, M. McGehee, S. Fan, and Y. Cui, Nano Lett. 9, 279 (2009). M. Fox, Optical properties of solids. New York, N.Y.: Oxford University Press, 2001. A. Arriagada, E. T. Yu, and P. R. Bandaru, Journal of Thermal Analysis and calorimetry 97, 1023 (2009). T. de Los Arcos, P. Oelhafen, and D. Mathys, Nanotechnology 18, 265706 (2007). [0116] While the present invention has been particularly shown and described with reference to the preferred mode as illustrated in the drawing, it will be understood by one skilled in the art that various changes in detail may be affected therein without departing from the spirit and scope of the invention as defined by the claims.

A monolithic optical absorber and methods of making same. The monolithic optical absorber uses an array of mutually aligned carbon nanotubes that are grown using a PECVD growth process and a structure that includes a conductive substrate, a refractory template layer and a nucleation layer. Monolithic optical absorbers made according to the described structure and method exhibit high absorptivity, high site densities (greater than 10 9 nanotubes/cm 2 ), very low reflectivity (below 1%), and high thermal stability in air (up to at least 400° C.). The PECVD process allows the application of such absorbers in a wide variety of end uses.

CROSS REFERENCE TO EXISTING APPLICATIONS This application is related to and claims priority from U.S. Provisional Patent Application No. 61/977,237 titled “Method and system for supporting dual-channel and diversity using two receivers” and filed Apr. 9, 2014, which is incorporated herein by reference in its entirety. FIELD Embodiments of the invention relate in general to wireless communication systems and methods, and in particular to systems and methods for dynamically controlled diversity reception of a plurality of different channels allocated dynamically to receivers. BACKGROUND Some wireless communication standards have a spectrum allocation of multiple wireless channels (frequency bands), where each channel has a distinct functionality and where several channels need to be processed concurrently. The channels are completely independent, receiving packets from different sources at different times. For example, the vehicle-to-vehicle (V2V) communication IEEE standard has seven allocated channels, of which one is allocated for safety and others for services. Concurrent reception of both the safety channel and of a service channel is required. Antenna diversity is a well-known method to improve the communication quality. Some implementations combine the signals from all antennas for maximal reception quality. This approach is called “full diversity”. Other implementations use only a subset of the antennas, since the number of processing elements denoted as “receivers” is lower than the number of antennas. The field of “switching diversity” or “switched diversity” involves studies of preferred antenna selection methods. A full diversity solution is more expensive than a switching diversity solution, because the size and complexity of full diversity implementation are higher. However, full diversity provides better communication quality. The switching diversity theory is focused on receiving a single source of data (single channel) at a time. However, in some communication environments such as V2V, independent data links are handled concurrently in different channels. Each channel uses a different frequency. Some V2V communication installations (or “systems”) mandate the use of two antennas for omni-directional antenna pattern. For full diversity implementation of two channels, the number of receivers has to be twice the number of channels, as two receivers have a fixed allocation to one channel. For example, a vehicle can use a single antenna if the antenna is positioned on the top of its roof. Other vehicles, like vehicles without observable antennas, need two antennas positioned either on windows, bumpers or side-mirrors. The term “dynamic control” with reference to receivers is known. Dynamically controlled diversity receivers are capable of performing various diversity receiving and processing schemes, however involving only one channel. The term “dynamic control” with reference to a receiver also refers to the configuration and capability of a receiver to select one or two antennas for reception of a single channel. FIG. 1A illustrates a known wireless communication system 100 that supports reception of two channels with full antenna diversity. System 100 includes exemplarily two antennas A and B that serve two channels. Each antenna covers a partial antenna. Together, the two antennas provide omnidirectional pattern. A splitter and combiner “block” per antenna (respectively blocks 102 and 104 ) is needed to operate two different channels with a single antenna. The splitter and combiner block is used to reduce the number of antennas. For example, blocks 102 and 104 could be dispensed with if four antennas were implemented and each antenna was routed directly to a receiver. Four receivers 106 , 108 , 110 and 112 are needed for implementation of full availability of this scheme. System 100 further includes two “full diversity” receivers 114 and 116 , each receiving two antennas and performing full diversity reception. Each receiver outputs a respective channel, respectively channels 1 and 2. Such a system is feasible but expensive and requires a large physical size. FIG. 1B illustrates a known wireless communication system 100 ′ that supports reception of two channels with switched antenna diversity. System 100 ′ is similar to system 100 but includes two diversity switches 122 and 124 coupled respectively to two “regular” receivers 126 and 128 instead of the two full diversity receivers 114 and 116 . Each diversity switch receives two antennas and selects one antenna for processing at the respective receiver. Each receiver processes a single antenna and outputs a single channel (respectively channels 1 and 2) but does not provide receiver gain. The switching control is described in known switched diversity art. Such a system is feasible but shows limited performance where diversity gain is needed. There is therefore a need for, and it would be highly desirable to have systems and related methods that handle multiple channels with dynamically controlled diversity reception, i.e. with a number of receivers that is smaller than twice the number of channels, to reduce system cost and size. SUMMARY Embodiments disclosed herein relate to wireless communication systems that handle multiple data streams (multiple channels) with dynamically controlled diversity reception, i.e. with a number of receivers smaller than twice the number of channels. Each receiver is associated with a receiver chain (not shown). Hereinafter, “receiver” and “receiver chain” (or simply “chain”) may be used interchangeably. Dynamically controlled reception as disclosed herein, in which the number of receivers is smaller than twice the number of channels, is termed “multi-channel dynamically controlled diversity reception” or “multi-channel multi-receiver dynamically controlled diversity reception”. In various embodiments, some of which are described in detail hereinbelow, multi-channel dynamically controlled diversity reception is applied to multiple channels by using (or performing) dynamic multiple channel allocation. In some multi-channel dynamically controlled diversity reception system and method embodiments disclosed herein, the number of receivers can be equal to the number of channels, providing a system with minimal antenna count but with some compromised availability. In some embodiments, the number of receivers is larger than the number of channels but smaller than twice the number of channels. While described in detail with reference to two antennas, systems and methods disclosed herein can be generalized to support more antennas, for example three antennas. In an embodiment there is provided a system for wireless communication, comprising a plurality M of receivers coupled to M antennas and configured to handle N communication channels wherein N≦M≦(2*N−1) and N channel state machines configured to dynamically allocate multiple channels of the N channels to the M receivers to support dynamic switched diversity for multi-channel dynamically controlled reception. In an embodiment, a system further includes an arbitration component configured to arbitrate between channel state machines when such channel state machines work concurrently. The arbitration may include allocation of a different time slot to each channel state machine or includes allocation of an available receiver per priority of a processed channel. In an embodiment, each channel state machine is configured to control the operation of each receiver. In an embodiment, each receiver is dynamically configured to process a single channel. In an embodiment, a system further includes a fast lock control mechanism operative to accelerate the locking time of one receiver based on at least one parameter received from another receiver. The fast lock mechanism may include, for each channel state machine, a lock state machine configured to receive an input parameter and a copy command parameter from another lock state machine. The input parameter may be an initial receiver gain, a frequency shift or a combination of the two. The copy command parameter may include a set gain command, a frequency shift command and a combination of the two. In an embodiment there is provided a method for wireless communication, comprising steps of providing a plurality M of receivers coupled to M antennas and configured to handle N communication channels wherein N≦M≦(2*N−1), and dynamically allocating the N channels to the M receivers while considering channel priority, thereby supporting dynamic switched diversity for multi-channel dynamically controlled reception. The step of dynamically allocating may include configuring N channel state machines to perform dynamic allocation of multiple channels to receivers and dynamically configuring each receiver to process a single channel. The dynamic configuring may include accelerating the locking time of one receiver based on at least one parameter received from another receiver. The acceleration is performed by a lock state machine included in each channel state machine, each lock state machine configured to receive an input parameter and a copy command parameter from another lock state machine. In an embodiment, a method further includes the step of arbitrating between channel state machines when such channel state machines work concurrently. The arbitration may include allocating a different time slot to each channel state machine, or allocating an available receiver per priority of a processed channel. BRIEF DESCRIPTION OF THE DRAWINGS Non-limiting embodiments are herein described, by way of example only, with reference to the accompanying drawings, wherein: FIG. 1A illustrates a known wireless communication system that supports reception of two channels with antenna full diversity; FIG. 1B illustrates a known wireless communication system that supports reception of two channels with antenna switching diversity; FIG. 2A illustrates an embodiment of a wireless communication system that supports two-channel two-receiver dynamically controlled diversity reception; FIG. 2B illustrates an embodiment of a wireless communication system that supports three-channel three-receiver so dynamically controlled diversity reception; FIG. 3 illustrates an embodiment of a generalized wireless communication that supports multi-channel dynamically controlled diversity reception; FIG. 4 illustrates the operation of the fast lock control component in FIG. 3 ; FIG. 5 shows a state flow diagram implemented per channel. DETAILED DESCRIPTION FIG. 2A illustrates an embodiment numbered 200 of a wireless communication system that supports two-channel two-receiver dynamically controlled diversity reception. System 200 includes two antennas, a first antenna A and a second antenna B coupled through respective receivers and inputs 202 and 204 to a dual-channel dynamically controlled receiver 206 that includes two receivers, a receiver 208 and a receiver 210 . In system 200 , the number of receivers is equal to the number of channels. Each antenna has a fixed route to dual-channel dynamically controlled receiver 206 , but since receiver 206 can be dynamically allocated to each channel, each antenna can serve both channels. The system outputs channels 1 and 2, where the output is taken from the receiver currently allocated for the channel. This means that output channel 1 can result from receiver 208 , receiver 210 or a combination of both receivers. Similarly, output channel 2 can result from receiver 208 , receiver 210 or a combination of both receivers. The cost is halved relative to that of system 100 in FIG. 1A . The complexity of RF design is lower, due to the elimination of splitter and combiner blocks 102 and 104 of system 100 . An additional advantage of system 200 is the ability of each receiver 208 and 210 to be dynamically allocated to a different channel, and the combination of this ability with multi-channel dynamically controlled diversity reception, a combination that decides which antenna(s) will be used for reception. In use, in an idle state when no packet is received, the two channels are monitored continuously, each by a different receiver (routed to a fixed antenna). When a packet start is detected under certain conditions (e.g. once measured packet energy crosses a threshold and signal properties are validated), one receiver receives the channel in which the packet start is detected. The other receiver is then dynamically allocated to the channel by switching to receive the channel. That is, both receivers process the preamble of the same packet. If antenna diversity provides a noticeable reception processing gain (e.g. an improvement from, for example, a 40% expected packet error to 10% expected packet error), more specifically if the measured packet energies at both antennas are similar, and if the probability of receiving a packet at a single antenna without diversity is below a preset target (exemplarily 1% or 10%), both receivers will keep receiving the same channel in diversity mode. Otherwise, the receiver with the higher measured packet energy chain will receive the packet, while the other receiver will return to monitor the other channel. System 200 and its method of use ensure that availability to receive a packet from any source is as high as possible, and that diversity gain is provided when needed and possible. The scheme can allocate different importance priority to each channel and set a different availability target for each channel by allocating priorities to an arbitration component ( 306 in FIG. 3 ). For example, in V2V communication, one channel is used for safety, which should have perfect or near perfect availability, while the other channels are used for services, where availability can be compromised. FIG. 2B illustrates an embodiment numbered 200 ′ of a wireless communication system that supports three-channel three-receiver dynamically controlled diversity reception. The system illustrated in FIG. 2B has a higher number of receivers than the number of channels but a lower number of receivers than twice the number of channels. Like system 200 , system 200 ′ includes a first antenna A and a second antenna B. These antennas are coupled through three receivers 220 , 222 and 224 to a three-channel dynamically controlled receiver 206 ′ having 3 receivers 226 , 228 and 230 . Receivers 220 and 222 are routed directly to antenna A via a splitter/combiner block 232 . Receiver 224 is routed directly to antenna B. In use, both channels monitor continuously antenna A. Antenna B serves one channel based on need. Three-channel dynamically controlled receiver 206 ′ thus supports concurrent operation of 3 receivers. While receiver 206 ′ is potentially more expensive than receiver 206 , it provides full availability. Like system 200 , system 200 ′ provides dynamic allocation of receivers to channels and applies multi-channel dynamically controlled reception. The only difference lies in the added receiver resources in system 200 ′. FIG. 3 illustrates an embodiment numbered 300 of a generalized wireless communication system with multi-channel dynamically controlled diversity reception. System 300 includes M receivers 302 1-M for processing N channels. M may vary between N and 2*N−1, where N is 2 or larger. It should be understood that the M receivers coupled to the N-channels provide a “N-channel M-receiver dynamically controlled receiver” (not shown). Each receiver can process a single channel, selected dynamically. Each receiver (and receiver) works in parallel with all other receivers. System 300 further includes N state machines marked 304 1-N for controlling the operation of each channel. Each state machine can control each receiver, determining the channel for processing and having indication about its activity and about the priority of the currently handled channel. In other words, the channel state machines perform dynamic allocation of receivers. System 300 further includes an arbitration component 306 that coordinates between the various state machines that work concurrently. Arbitration component 306 may be a hardware (HW) component or a software (SW) module. Arbitration component 306 may exemplarily implement arbitration schemes: 1) by allocating a different time slot to each channel state machine to ensure that at each given moment only one channel state machine can make decisions, or 2) by allocating available receiver per priority of processed channel and/or per need. System 300 further includes optionally a fast lock control mechanism 308 (typically HW, but also implementable as a SW module) that implements fast lock functionality of a receiver 302 . The entire locking process needs to converge in a very short time, during packet preamble. System 300 further includes a diversity combiner 310 for exchanging dynamically information between two or more receivers in order to provide diversity gain. The diversity combiner allows the receivers handling the same channel to process the channel collectively. FIG. 4 provides details of the fast lock control mechanism 308 in FIG. 3 . A lock state machine 402 (which is a subset of a channel state machine 304 in FIG. 3 ) of a receiver is modified vs. a known art lock state machine to receive two inputs: an input parameter 404 and a copy command parameter 406 . This means that the lock state machine dynamically changes from one receiver to another while adopting parameters existing in another lock state machine. This is in contrast with known lock state machines, which have no input. Such known lock state machines base their decision solely on the received signal. In known systems, there is no ability to exchange information between different lock state machines in order to accelerate locking of a lock state machine based on the temporal parameters of another state machine. When a command 406 to copy a parameter from a first receiver to a second receiver is issued by a channel state machine 304 after deciding to use the second receiver to process the channel, input parameter 404 and copy command parameter 406 are loaded to the lock state machine of the respective channel state machine and are used. Exemplarily, input parameter 404 may include an initial receiver gain and/or a frequency shift of the second receiver to minimize the time needed for measuring both the initial receiver gain and the frequency shift of the second receiver. An exemplary command may be “set gain to XX dB (where XX is for example 66 dB) and “apply a frequency shift of YY KHz” (where YY is for example 100 KHz). The parameters (input 404 and copy command 406 ) of the lock state machine are output at a parameters output interface 408 , for use (if needed) by other receivers. FIG. 5 shows a state flow diagram implemented per channel. N parallel instances of the state machine exist and work concurrently. This generic flow applies to any values of N and M. A particular state machine waits in an initial state 500 for packet start. The state machine relates to a single channel and can control two (first and second) receivers. A receiver may be available or unavailable. The receiver availability state may consider several properties: a) Receiver activity: if the receiver is active then using it will interfere to the currently received packet. In that case, decision to use the receiver should be more cautious. If receiver is inactive, then nothing prevents from using it. b) Measured packet energy: if the preliminary energy measurement is high, then there is no need to utilize the second receiver since the packet will be received anyhow. c) Channel priority: if the first receiver is active and if the processed channel has lower priority, then the channel can be interrupted. If the processed channel has higher priority, then it cannot be interrupted. d) Wireless properties: typically, wireless properties are unknown at packet start. However, if wireless properties information like delay spread or non-line-of-sight is available, then this information can be considered as well and may impact the decision. Complex wireless reception requires higher energy and will likely benefit more from diversity. Once a packet start is detected, the flow leaves state 500 . If a second receiver is unavailable, then the flow jumps to state 506 , where a packet is received using a single antenna, i.e. the same antenna used for packet detection. The flow stops following packet end and the state machine returns to wait for a new packet start in state 500 . If a second receiver is available when the state machine waits in initial state 500 and once a packet start is detected, the flow jumps to state 502 . In state 502 , the packet energy is measured by the second receiver and a decision to apply diversity or to receive using only a single antenna is based on the measured energy (for example, if the energy difference between energies measured at the two antennas is within a small value, for example 3 dB). If diversity is needed, then state 504 becomes active. If diversity is not needed, then state 506 becomes active. The receiver selected for reception is the one with the higher energy among the two. From both states 504 and 506 , the flow returns to state 500 once packet transmission ends. From state 504 , the flow can jump to state 506 if diversity was interrupted by another state machine with higher priority. The decision of diversity activation after state 502 considers the energy difference between the two receivers: diversity provides gain only when the packet has similar energy (e.g. within about 3 dB) in both receivers. If the difference the energy measured in the two different receivers is too high (e.g. about 3 dB) then there is no need to activate diversity. One advantage of the flow above is the ability to implement dynamic allocation of a lock state machine and ability to adopt parameters from another lock state machine. The state flow shown in FIG. 5 can operate with different considerations. For example, considerations after state 500 can be checked only after state 502 . That is, checks such as a check if a receiver is available or unavailable or the consideration of properties mentioned above can be deferred to state 502 instead of being checked in state 500 . EXAMPLES OF OPERATION Example 1 This example (related to FIG. 2A ) involves a configuration of two channels and two receivers. Channel 1 has higher priority than channel 2. Receiver 1 monitors channel 1. Receiver 2 monitors channel 2. A packet is detected at channel 2. Regardless of any signal property, the lower priority of channel 2 indicates that only receiver 2 will be allocated for its reception, even if the packet energy is low. The current status is that receiver 1 monitors channel 1 and receiver 2 receives channel 2. In continuation, a packet start is monitored for channel 1. The energy is low, and since channel 1 has higher priority, reception of channel 2 is interrupted and receiver 2 is now allocated for channel 1. The packet energy at receiver 2 is higher than measured at receiver 1, meaning that channel 1 can be received only from receiver 2. Receiver 1 becomes available, and is allocated for monitoring channel 2. The current status is that receiver 2 receives channel 1 and receiver 1 monitors channel 2. Thus, the packet received in channel 2 is lost. Example 2 This example (related to FIG. 2B ) involves a configuration of two channels and three receivers (with three receivers). Channel 1 has higher priority than channel 2. Receiver 1 monitors channel 1 and receiver 2 monitors channel 2. A packet is detected at channel 2. The packet energy is low, and since receiver 3 is available, it switches to channel 2 and measures the packet energy. The switching is done by a frequency change command and by applying the fast lock mechanism. The measured packet energy is similar to the packet energy measured at receiver 2, and therefore diversity reception is activated. The current status is that receiver 1 monitors channel 1, and receivers 2 and 3 is receive channel 2. In continuation, a packet start is monitored for channel 1. The energy is low, and since channel 1 has higher priority, the diversity of channel 2 is interrupted and receiver 3 is now allocated to channel 1. The packet energy of receiver 3 is higher than that measured at receiver 1, and channel 1 is received only from receiver 3. The current status is that receiver 3 receives channel 1 and receiver 2 receives channel 2. While this disclosure has been described in terms of certain embodiments and generally associated methods, alterations and permutations of the embodiments and methods will be apparent to those skilled in the art. The disclosure is to be understood as not limited by the specific embodiments described herein, but only by the scope of the appended claims.

Systems for supporting multi-channel dynamically controlled diversity reception in wireless communications include a plurality M of receivers coupled to M antennas and configured handle N communication channels wherein N≦M≦(2*N−1) and N channel state machines configured to dynamically allocate multiple channels of the N channels to the M receivers to support dynamic switched diversity for multi-channel dynamically controlled reception. Each channel state machine is configured to control the operation of each receiver. Arbitration is performed between channel state machines when such channel state machines work concurrently. In some embodiments, a lock state machine inside each channel state machine accelerates the locking time of a receiver based on at least one parameter received from another receiver.

RELATED APPLICATION(S) [0001] This application is a divisional of U.S. application Ser. No. 13/541,107, filed Jul. 3, 2012, which is a divisional of U.S. application Ser. No. 12/479,513, filed Jun. 5, 2009, now U.S. Pat. No. 8,220,643, which claims the benefit of U.S. Provisional Application No. 61/059,610, filed on Jun. 6, 2008. The entire teachings of the above application(s) are incorporated herein by reference. TECHNICAL FIELD [0002] The following disclosure relates to sorbent materials for separating and/or removing urea from dialysate solutions in sorbent-based dialysis treatment or for separating and/or removing urea from aqueous solutions or liquids in medical related processes or circumstances. BACKGROUND [0003] Hemodialysis is a process by which toxins and other molecules, such as urea, are removed from the blood using a semi-permeable filtering membrane. Typically, the patient's blood and an aqueous solution (i.e., dialysate) are pumped in counter-direction flows in and about hollow, semi-permeable fibers. In FIG. 1 a known configuration of a dialyzer is shown. Generally, blood flows in one end of the dialyzer and through hollow semi-porous or semipermeable fibers toward the blood output side of the dialyzer. Meanwhile, dialysate flows in an opposite direction, with respect to the blood flow, by entering a dialysate inlet and flowing around or about the semi-porous hollow fibers in which the blood is flowing. The dialysate then exits the dialysate outlet. The toxins within the blood are removed from the blood via a combination of diffusion, convection, and osmosis processes while the blood is flowing within the fibers and the dialysate is flowing outside the fibers. Generally, the dialyzer is comprised of a large number of semi-permeable hollow fibers bundled together and placed in a cylindrical jacket as shown. Present day dialysis processes may be classified as: 1) single pass; and 2) sorbent-based. Single pass processes require a continuous supply of gallons of fresh and treated water. The treated water may be purified by for example, reverse osmosis or distillation. The gallons of fresh and treated water are used to create the dialysis fluid, which is discarded after flowing through the dialyzer and collecting the toxins in a single pass through of the dialyzer. [0004] FIG. 2 shows a schematic/diagram of a cross section of a single semi-permeable fiber that may be used in a dialyzer. The blood flows through the hollow lumen within the semi-permeable walls of the fiber. The membrane walls have a thickness, which is the difference of the radius R 2 minus the radius R 1 . The membrane is semi-permeable and the dialysate, as shown, flows in the opposite direction outside of the semi-permeable fiber. [0005] Sorbent dialysis differs from single pass dialysis in that the dialysate is regenerated using a series of chemical powders to remove toxins from the dialysate solution. Typically, spent dialysate from the dialyzer is pumped through the first chemical layer of an enzyme called “urease”. The urease catalyzes the breakdown of urea into ammonia and carbon dioxide. The dialysate will then pass through a second chemical layer, a cation exchange layer (zirconium phosphate) which absorbs ammonia and other positively charged ions and then through a third, chemical layer, an anion exchange layer (hydrous zirconium oxide) where anions such as phosphate and fluoride are absorbed. Finally, the dialysate is pumped through a fourth layer of activated carbon where organic metabolites such as creatinine are absorbed. At some point, the filtered dialysate may be passed through a degasser to remove air, carbon dioxide and other gas bubbles that may form or be found in the dialysate. [0006] The capacity of the zirconium phosphate cation exchange layer to absorb ammonia is limited by the number of sites available to bind ammonia. If the zirconium phosphate layer is depleted, ammonia will remain in the dialysate as it is recycled to the dialyzer. In this case the patient may be at risk of ammonia toxicity. Consequently, the filtered dialysate must be periodically tested or monitored for ammonia concentration. [0007] A typical dialysis patient generates an excess of about 24 to about 60 grams of urea per day that must be removed from the blood to avoid uremia. Therefore, what is needed is a sorbent for use in dialysis that has the capacity to remove this quantity of urea in a reasonable time frame. Thus, suitable sorbents should have the capacity to remove approximately 2.5 grams per deciliter of dialysate per hour (gm/dl/hr) from the dialysate. SUMMARY [0008] In one embodiment, a urea sorbent is provided that is suitable for use in a sorbent-based dialysis process. The sorbent absorbs urea from the dialysate without generating ammonia or carbon dioxide, thereby eliminating the need for monitoring the concentration of ammonia in the dialysate as well as reducing or eliminating the need for de-gassing the dialysate. In one variation, the sorbent is insoluble or substantially insoluble in water and effective to remove urea from dialysate in a pH range of between 4 and 12 and more particularly in a pH range of between about 6 and 8. In another embodiment the sorbent is soluble or substantially soluble and effective to bond with urea to remove, or bind urea from a dialysate solution or other aqueous solution. [0009] In another aspect, a filter for regenerating dialysate includes a sorbent layer comprising a polymer having specific functional groups bonded thereto that interact or react with urea at a pH of between 4 and 12, and more particularly at a pH of between 6 and 8, to remove urea from an aqueous solution. The exemplary polymer may be any one of soluble, substantially soluble, insoluble and substantially insoluble in water. The exemplary polymer further reacts or interacts with urea while near room temperature or while in a defined temperature range between about 50° F. and 110° F. without releasing ammonia or generating carbon dioxide. The reaction product of the polymer and urea may also be any one of soluble, substantially soluble, insoluble and substantially insoluble in water. A second filter layer may be used with the exemplary polymer sorbent. The second filter layer comprises activated carbon for absorbing organic metabolites from the dialysate or other aqueous solution. In one variation, the filter further includes an anion exchange layer for removing anions from the dialysate. [0010] In another aspect, a filter for removing urea from an aqueous solution or liquid is provided. The filter comprises a sorbent layer or coating. The sorbent layer or coating comprises a polymer having specific functional groups bonded thereto. The exemplary polymer having specific functional groups bonded thereto interacts or reacts with urea at a pH of between 4 and 12 or a predetermined bounded pH range therebetween (i.e., 3 to 7, 5-9, 6-8, etc.) Upon interaction or perhaps a reaction with urea, urea is bonded to the exemplary sorbent polymer and removed from an aqueous solution. An exemplary polymer may be soluble, substantially soluble, insoluble, or substantially insoluble in water. Furthermore, an exemplary polymer reacts with urea at near room temperature or other predetermined temperature range without releasing ammonia or generating carbon dioxide. In various aspects, an exemplary polymer reacts or interacts with urea to produce a single reaction product. The filter may also include activated carbon for adsorbing and removing other molecules from the aqueous solution. The reaction product produced by the reaction or interaction of an exemplary polymer and urea may be soluble, substantially soluble, insoluble, or substantially insoluble in water. BRIEF DESCRIPTION OF THE DRAWINGS [0011] For a more complete understanding, reference is now made to the following description taken in conjunction with the accompanying Drawings in which: [0012] FIG. 1 illustrates a diagram of a dialyzer; and [0013] FIG. 2 illustrates a cross-sectional diagram of a fiber lumen in a dialyzer. DETAILED DESCRIPTION [0014] Referring now to the drawings, the various views and embodiments of exemplary urea sorbents are illustrated and described, and other possible embodiments are described. The figures are not necessarily drawn to scale, and in some instances the drawings have been exaggerated and/or simplified in places for illustrative purposes only. One of ordinary skill in the art will appreciate the many possible applications and variations based on the following examples of possible embodiments. [0015] Sorbent Preparation: 1. Preparation of MPS-IV-048 (Polyvinylglyoxalate) [0016] [0017] 1.1 Reagents [0000] Entry Reagent/solvent Amount mmol Equivalent 1 Polyvinyl alcohol 1.000 g 5.0 × 10 −3 1 (M. wt. = 205000) (23.3 mmol of alcohol units) 2 Glyoxylic acid 2.144 g 23.30 1 monohydrate (M. wt. = 92) 3 EDC•HC1 (M. wt. = 3.973 g 20.72 0.88 191.71) 4 Distilled water   15 ml [0018] 1.2 Procedure. [0019] To a stirred solution of glyoxylic acid monohydrate and EDC.HCl in distilled water, polyvinyl alcohol was added stirred the solution for 24 h. Water was evaporated under reduced pressure to obtain a gum, which was used for urea trapping experiments from the dialysis solutions. 2. Preparation of MPS-IV-054 (Polyvinylglyoxalate) [0020] [0021] 2.1 Reagents [0000] Entry Reagent/solvent Amount mmol Equivalent 1 Polyvinyl alcohol (M. 1.000 g 5.0 × 10 −3 1 wt. = 205000) (23.3 mmol of alcohol units) 2 Glyoxylic acid 2.144 g 23.30 1 monohydrate (M. wt. = 92) 3 NaH (M. wt. = 1.538 g 0.846 1.51 24 55-60% in suspension) 4 Dry-N,N-   10 ml Dimethylformamide (DMF) [0022] 2.2 Procedure [0023] Sodium hydride was added to a cooled (0° C., ice bath) stirred suspension of polyvinyl alcohol in dry DMF and stirring continued for 2-3 min. Glyoxylic acid monohydrate was added to this mixture and the mixture was brought to room temperature after 2 h stirring at 0° C. Stirring continued for overnight. The solid obtained was washed with DCM and used for urea trapping experiments from the dialysis solutions. [0024] 2.3 Properties Weight of MPS-IV-054=3.691 g Melting Point of MPS-IV-054=doesn't melt up to 290 0° C. Mn=75540; Mw=79736; ρ=1.055 g/cm3 3. Preparation of MPS-V-003 (Bis(Polyvinyloxalate)) [0028] [0029] 3.1 Reagents [0000] Entry Reagent/solvent Amount mmol Equivalent 1 Polyvinyl alcohol 1.000 g 5.0 × 10 −3 1 (M. wt. = 205000) (23.3 mmol of alcohol units) 2 Oxalic acid (M. wt. = 2.000 g 25.64 1.1 78) 3 EDC•HC1 (M. wt. = 3.973 g 20.72 0.88 191.71) 4 Distilled water   20 ml [0030] 3.2 Procedure [0031] To a stirred solution of oxalic acid and EDC.HCl in distilled water, polyvinyl alcohol was added stirred the solution for 24 h. Water was evaporated under reduced pressure to obtain a gum, which was used for urea trapping experiments from the dialysis solutions. [0032] 3.3 Properties Weight of MPS-V-003=6.20 g 4. Preparation of MPS-V-004 (Polyvinylpyruvate) [0034] [0035] 4.1 Reagents [0000] Entry Reagent/solvent Amount mmol Equivalent 1 Polyvinyl alcohol 1.000 g 5.0 × 10 −3 1 (M. wt. = 205000) (23.3 mmol of alcohol units) 2 Pyruvic acid  2.10 ml 25.28 1.1 (M. wt. = 88.06; d = (≡2.226 g) 1.06) 3 EDC•HC1 (M. wt. =  3.92 g 20.44 0.88 191.71) 4 Distilled water   15 ml [0036] 4.2 Procedure [0037] To a stirred solution of pyruvic acid and EDC.HCl in distilled water, polyvinyl alcohol was added stirred the solution for 24 h. Water was evaporated under reduced pressure to obtain a gum, which was used for urea trapping experiments from the dialysis solutions. [0038] 4.3 Properties Weight of MPS-V-004=6.42 g 5. Preparation of MPS-V-005 (Polyvinylbezoate 0.33 Polyvinylalcohol 0.66) [0040] [0041] 5.1 Reagents [0000] Entry Reagent/solvent Amount mmol Equivalent 1 2.000 g 1.0 × 10 −2 1 × 10 −2 1 Polyvinyl (46.6 mmol (46.6 mmole alcohol of alcohol of alcohol (M. wt. = units) units) 205000) 2 Benzoyl chloride 2.00 ml 17.23 0.37 (M. wt. = (≡2.422 g) 130.57; d = 1.211) 3 Dry pyridine   25 ml [0042] 5.2 Procedure [0043] To a stirred, cooled (0° C., ice bath) solution of polyvinyl alcohol in dry pyridine (17 ml), a solution of benzoyl chloride in dry pyridine (8 ml) was added dropwise over a period of 10 min and stirring continued for 24 h with gradual increase in reaction temperature to rt. After 24 h, the pyridine was removed under reduced pressure and by co-evaporation with toluene to obtain a gum which was used for next step. The gum (MPS-V-005) swelled when brought in contact with solvents like ethyl acetate, dichloromethane (DCM), chloroform and methanol. 6. Preparation of MPS-IV-009 (Polyvinylbezoate 0.33 Polyvinylglyoxalate 0.66) [0044] [0045] 6.1 Reagents [0000] Entry Reagent/solvent Amount mmol Equivalent 1 MPS-V-005 2.000 g (29.3 mmol of 1 alcohol units) 2 Glyoxylic acid 0.920 g 10.00 0.34 monohydrate (M. wt. = 92) 3 EDC•HC1 (M.  1.55 g 10.00 0.34 wt. = 191.71) 4 Distilled water   20 ml [0046] 6.2 Procedure [0047] A solution of glyoxylic acid monohydrate and EDC.HCl in distilled water was added to MPS-V-005 and the suspension was stirred at room temperature for 48 h. The white ppt obtained was filtered off, dried and used for urea trapping experiments from the dialysis solutions. [0048] 6.3 Properties Weight of MPS-V-009=1.543 g 7. Preparation of MPS-V-027 (Polyvinylglyoxalate-Ethylene Copolymer) [0050] [0051] 7.1 Reagents [0000] Entry Reagent/solvent Amount mmol Equivalent 1 Polyvinyl alcohol-  2.28 g 41.67 mmol 1 coethylene (27% (≡1.838 g of of ethylene) polyvinyl alcohol) OH group 2 Glyoxalic acid  4.00 g  43.48 1.04 monohydrate (M. wt. = 92) 3 NaH (M. wt. = 1.200 g  50.00 1.2 24 55-60% in suspension) 4 Thionyl chloride 12 (≡19.572 g) 164.51 3.78 (M. wt. = 118.97, d = 1.613) 5 Dry-N,N-   30 ml Dimethylformamide (DMF) [0052] 7.2 Procedure [0053] Glyoxylic acid monohydrate was dissolved in thionyl chloride and the mixture was refluxed for 48 h. Removal of excess thionyl chloride under vacuum gave a gum (glyoxaloyl chloride). Polyvinyl alcohol co-ethylene was dissolved in dry DMF (by warming up to 100° C.) and this solution was added (after cooling to about 40° C.) to the previously obtained gum. The mixture was stirred for about 30 min in ice bath and NaH was added. Stirring continued for overnight after removal of the ice bath to obtain a sticky solid which was used for the urea trapping experiments from the dialysis solutions. [0054] 7.3 Properties Weight of MPS-V-027=4.763 g 8. Preparation of MPS-V-036 [0056] (polyacrylicacid 0.9 polyvinylpolyacrylicacid 0.1 ) [0000] [0057] 8.1 Reagents [0000] Entry Reagent/solvent Amount mmol Equivalent 1 Poly(acrylic acid) 1.500 g 3.75 × 10 −4 1 (M. wt. = 4000000) (20.83 mmol of —COOH units) 2 Polyvinyl alcohol 1.000 g 4.88 × 10 −4 0.1 (M. wt. = 205000) (2.27 mmol of —OH units) 3 EDC•HC1 0.479 g 2.49 1.1 eq of —OH (M. wt. = 191.71) groups 4 Distilled water   50 ml [0058] 8.2 Procedure [0059] Poly (acrylic acid) was added to a stirred solution of EDC.HCl in distilled water. To this stirred suspension, polyvinyl alcohol was added and the solution was stirred for overnight. The gel obtained was filtered under suction (vacuum pump), washed with water, methanol, dichloromethane (DCM), acetone and ether respectively and dried for one week at room temperature to obtain a glassy solid, which was used for urea trapping experiments from the dialysis solutions. [0060] 8.3 Properties Weight of MPS-V-036=3.361 g 9. Preparation of MPS-V-037 (Polyvinylpyrurate-Ethylene Copolymer) [0062] [0063] 9.1 Reagents [0000] Entry Reagent/solvent Amount mmol Equivalent 1 Polyvinyl alcohol-  1.14 g 20.84 mmol 1 coethylene (27% (≡0.909 g of of OH group ethylene) polyvinyl alcohol) 2 Pyruvic acid  1.90 ml 27.19 1.3 (M. wt. = (≡2.394 g) 88.06, d = 1.26) 3 DCC 6.450 g 31.26 1.5 (M. wt. 206.33) 4 DMAP (M. wt. = 0.382 g  3.13 0.15 122.17) 5 Dry-N,N-   30 ml Dimethylformamide (DMF) [0064] 9.2 Procedure [0065] Polyvinyl alcohol co-ethylene was dissolved in DMF (15 ml) by heating the mixture to 100° C. This solution (after cooling to 40° C.) was added to a mixture of pyruvic acid, dicyclohexyl carbodiimide (DCC) and 4-dimethylaminopyridine (DMAP) in dry DMF (15 ml) and the reaction mixture was stirred at room temperature for overnight. The solid obtained was filtered off, washed with water, methanol, dichloromethane (DCM), acetone and ether respectively, dried and used for the urea trapping experiments from the dialysis solutions. [0066] 9.3 Properties Weight of MPS-V-037=6.305 g 10. Preparation of MPS-V-038 (Polyvinylglyoxalate-Ethylene Copolymer) [0068] [0069] 10.1 Reagents [0000] Entry Reagent/solvent Amount mmol Equivalent 1 Polyvinyl alcohol-  1.14 g 20.84 mmol 1 coethylene (27% (≡0.909 g of of OH group ethylene) polyvinyl alcohol) 2 Glyoxylic acid 2.400 g 26.09 1.25 monohydrate (M. wt. = 92) 3 DCC (M. wt. = 6.450 g 31.26 1.5 206.33) 4 DMAP (M. wt. = 0.382 g  3.13 0.15 122.17) 5 Dry-N,N-   30 ml Dimethylformamide (DMF) [0070] 10.2 Procedure [0071] Polyvinyl alcohol co-ethylene was dissolved in DMF (15 ml) by heating the mixture to 100° C. This solution (after cooling to 40° C.) was added to a mixture of glyoxylic acid monohydrate, dicyclohexyl carbodiimide (DCC) and 4-dimethylaminopyridine (DMAP) in dry DMF (15 ml) and the reaction mixture was stirred at room temperature for overnight. The solid obtained was filtered off, washed with water, methanol, dichloromethane (DCM), acetone and ether respectively, dried and used for the urea trapping experiments from the dialysis solutions. [0072] 10.3 Properties Weight of MPS-V-038=6.025 g 11. Preparation of MPS-V-047 (Isopropylaminepolyacrylicamide) [0074] [0075] 11.1 Reagents [0000] Entry Reagent/solvent Amount mmol Equivalent 1 Poly(acrylic acid) 1.500 g 3.75 × 10 −4 1 (M. wt. = 4000000) (20.83 mmol of —COOH units) 2 iso-Propylamine (M.  0.20 ml 2.33 0.11 wt. = 59.11, d = (≡0.138 g) 0.688) 3 EDC•HC1 (M. wt. = 0.479 g 2.49 1.1 eq of 191.71) —OH groups 4 Distilled water   50 ml [0076] 11.2 Procedure [0077] Poly(acrylic acid) was added to a stirred solution of EDC.HCl in distilled water. To this stirred suspension, iso-propylamine was added and the solution was stirred for overnight. The gel obtained was filtered under suction (vacuum pump), washed with water, methanol, dichloromethane (DCM), acetone and ether respectively and dried for one week at room temperature to obtain a thick gel (like a glassy solid), which was used for urea trapping experiments from the dialysis solutions. [0078] 11.3 Properties Weight of MPS-V-047=2.46 g [0080] Dialysate solutions were analyzed for nitrogen content and the amount of urea in the dialysate was calculated. In some cases, additional urea was added to the solution as indicated in column 2 of each Table (1-5). The polymer reagent was added to the solution in the amount indicated in column 3. The mixture was stirred at room temperature for one hour and filtered. The filtrate was analyzed and the amount of urea removed from the dialysate solution was determined. A minus sign (−) indicates that the results were inconclusive. [0081] In the following tables, the title identifies the particular polymer reagent tested. The first column of each table represents the experiment or run number. The second column identifies the particular dialysate solution used for the experiment and whether additional urea was added to the solution. The third column indicates the amount of polymer reagent used in the experiment. The fourth column gives the reaction conditions e.g. time and temperature. (Note: rt=room temperature). It is further understood that room temperature is between about 60 and 78° F. (about 15.56° C. to about 25.56° C.) and that reactions will also occur in a temperature range of between about 50° F. to about 110° F. (about 10° C. to about 43.3° C.). It is believed that reactions will also occur at colder or warmer temperatures, but such reactions have not been specifically tested. The fifth column identifies the analyzed portion of the reaction mixture (e.g. filtrate). In some cases, a neutralizing agent was added to the filtrate. The sixth column (BUN or Blood Urea Nitrogen) provides the concentration of nitrogen in the particular dialysate solution used for the experiment. The seventh column gives the amount of urea in the solution. The eighth column contains the maximum amount of urea in the solution. In the cases where additional urea was added as indicated in column 2, this number will be higher than the corresponding entry in the sixth column. The ninth column is the amount of urea removed from the dialysate solution. The first row of each table provides the nitrogen, urea and maximum or total amount of urea present in the dialysate solution used in the experiments. [0000] TABLE 1 MPS-IV-048 Results (in mg/dL) Amount of Analyzed Blood Blood Maximum Amount Reagent portion of Urea Urea amount of of urea Soln Used Reaction reaction Nitrogen (BUN × urea taken out Entry compn (g) condn. mixture (BUN) 2.14) present (mg/dL/h) 1 Soln-3 — — — 7.8 16.692 16.692 — Blank (10 ml) 2 Soln-3  2 rt, 1 h Filtrate 14.6 31.244 16.692 (−) 14.552 (10 ml) (8 mL) 3 Soln-3 13 rt, 1 h Filtrate 797.2 1706.0 2516.7 810.7 (20 ml) + (0.50 g) (10 mL) Urea (0.50 g) [0000] TABLE 2 MPS-IV-OS4 and MPS-V-009 Results (in mg/dL) Analyzed Amount Amount of portion Blood Blood Maximum of urea Reagent of Urea Urea amount of taken Soln Used Reaction reaction Nitrogen (BUN × urea out Entry compn (g) condn. mixture (BUN) 2.14) present (mg/dL/h) 1 Soln-3 — — — 4 8.56 8.56 — Blank (10 ml) MPS-IV-054 2 Soln-3 2.5  rt, 1 h Filtrate 2227 4765.78 5008.56 242.78 (20 ml) + (5 ml; Urea pH = 10) (0.50 g) 3 Soln-3 2.50 rt, 1 h Filtrate 2523 5399.22 5008.56 (−) (10 ml) + (3 ml; 390.66 Urea pH = 10) + (1.00 g) 2% HCI- (0.4 ml) to neutralize to pH = 7 MPS-V-009 4 Soln-3 1.26 rt, 1 h Filtrate 2563 5484.82 2508.56 (−) (10 ml) + (3 ml; 2976.26  Urea pH = 7) (0.50 g) [0000] TABLE 3 MPS-V-003 Results (in mg/dL) Amount of Analyzed Blood Blood Maximum Amount Reagent portion of Urea Urea amount of of urea Soln Used Reaction reaction Nitrogen (BUN × urea taken out Entry compn (g) condn. mixture (BUN) 2.14) present (mg/dL/h) 1 Soln-3 — — — 4 8.56 8.56 — (10 ml) Blank 2 Soln-3 rt, 1 h Filtrate 2257 4740 5008 268.3 (20 ml) + (5 mL; Urea pH = 1) (1.00 g) 3 Soln-3 rt, 1 h Filtrate 1527 3267.78 5008 1740.22 (20 ml) + (3 m; Urea pH = 1) + (1.00 g) saturated HCO3 (1 ml) to neutralize to pH = 7 [0000] TABLE 4 MPS-V-027 and MPS-V-036 Results (in mg/dL) Amount Amount Analyzed Blood Blood Maximum of urea of portion of Urea Urea amount of taken Soln Reagent Reaction reaction Nitrogen (BUN × urea out Entry compn Used (g) condn. mixture (BUN) 2.14) present (mg/dL/h) 1 Soln-4 — — — 88 188.32 188.32 — Blank (9 ml) 2 Soln-4 MPS-V rt, 1 h Filtrate 0 0 2688.32 2688.32 (10 ml) + 036 (2 ml) Urea (residue (pH = 6~7) (0.50 g) after filtration) (2.28 g) 3 Soln-4 MPS-V rt, 1 h Filtrate 1114 2339.4 2688.32 349.3 (10 ml) + 027 (4 ml) Urea (residue (pH = 7~8) (0.50 g) after filtration and washing with MeOH) (4.40 g) [0000] TABLE 5 MPS-V-037, MPS-V-038 and MPS-V-047 Data for Solution-4 Results (in mg/dL) Amount Amount Analyzed Blood Blood Maximum of urea of portion of Urea Urea amount of taken Soln Reagent Reaction reaction Nitrogen (BUN × urea out Entry compn Used (g) condn. mixture (BUN) 2.14) present (mg/dL/h) 1 Soln-4 — — — 25 53..5 53..5 — Blank (9 ml) 2 Soln-4  2 rt, 1 h Filtrate 0 0 5053.5 5053.5 (20 ml) + (10 ml) Urea (pH-7) (1.00 g) 3 Soln-4 13 rt, 1 h Filtrate 0 0 2553.5 2553.5 (10 ml) + (0.50 g) (10 ml) Urea (pH-7) (0.50 g) 4 Soln-4 MPS-V rt, 1 h Filtrate 479 1025.06 2553.5 1528.44 (10 ml) + 047 (5 ml) Urea (2.46 g) (pH = 5) (0.50 g) [0082] As will be appreciated from the foregoing, vinyl polymers having specific functional groups selected from carboxylic acids, esters and salts, amides, dicarboxylic acids, and esters and salts may be formulated to provide sorbents suitable for use in removing urea from an aqueous solution having a pH from about 6 to 8. Other sorbents suitable for removing urea from an aqueous solution having a pH range from 4 to 12 are realizable with various ones of the aforementioned specific functional groups by one of ordinary skill in the art having the information contained herein. Such exemplary polymers are substantially insoluble in water and can remove urea from dialysate at a rate of at least 2.5 mg/dl/hr. Additionally, such polymers may be soluble, substantially soluble or insoluble in water depending on variations in their manufacture. [0083] In some variations of the invention, vinyl polymers such as polyvinyl alcohol, polyvinyl alcohol-ethylene co-polymers and polyacrylic acid are reacted with specific functional groups selected from carboxylic acids, carboxylic acid esters, carboxylates, amides, dicarboxylic acids, dicarboxylic acid esters, and dicarboxylates to produce the desired exemplary sorbents. Exemplary polymers may be applied to various substrates for use as dialysis sorbents. Such substrates may be organic or inorganic and may include filter paper, plastic or glass beads and other particulate materials that are insoluble in water. The polymers may also be applied to various screens and mesh-type filter materials formed from wire or plastic strands or cloth. [0084] Another advantage of an exemplary urea sorbent is the use of selective functional groups that can be utilized to make a variety of resultant exemplary sorbents ranging from being soluble, insoluble, a liquid, a gum, an adhesive, a flexible material, a coating as well as a solid or powder. [0085] It will be appreciated by those skilled in the art having the benefit of this disclosure that this urea sorbent provides a viable replacement for prior known dialysis sorbent materials. It should be understood that the drawings and detailed description herein are to be regarded in an illustrative rather than a restrictive manner, and are not intended to be limiting to the particular forms and examples disclosed. On the contrary, included are any further modifications, changes, rearrangements, substitutions, alternatives, design choices, and embodiments apparent to those of ordinary skill in the art, without departing from the spirit and scope hereof, as defined by the following claims. Thus, it is intended that the following claims be interpreted to embrace all such further modifications, changes, rearrangements, substitutions, alternatives, design choices, and embodiments. [0086] While this invention has been particularly shown and described with references to example embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims.

A sorbent polymer is provided that interacts or reacts with aqueous urea to aid the regeneration of a dialysate liquid. The sorbent polymer may include one or more specific functional groups bonded thereto. Such specific functional groups are selected from carboxylic acids, carboxylic acid esters, carboxylates, amides, dicarboxylic acids, dicarboxylic acid esters, and dicer boxylates to produce the desired urea sorbent.

CLAIM OF PRIORITY [0001] This application is Continuation of U.S. patent application Ser. No. 13/569,834 filed on Aug. 8, 2012 and claiming priority of U.S. Pat. No. 8,448,401 filed as application Ser. No. 13/029,336 on Feb. 17, 2011 which claims priority to U.S. Ser. No. 61/305,255 filed Feb. 17, 2010, the contents of all of which are fully incorporated herein by reference. FIELD OF THE INVENTION [0002] The invention relates to the installation of building siding, and more particularly to insulation board and processes related to installing the insulation. BACKGROUND OF THE INVENTION [0003] Houses in America often have their exterior walls clad with siding to protect the predominately wooden construction from the elements. Vinyl siding has become particularly popular over the last several decades as it is inexpensive, relatively easy to clean and relatively durable. However, in recent years, fiber cement siding has begun to replace vinyl siding. Fiber cement is a product made of sand, cement and cellulose. As a siding material, fiber cement has advantages over both wood and vinyl in that it is rot resistant, termite resistant and non-combustible. Because of these properties fiber cement siding has become widely used in bush fire regions of Australia, and is now becoming a material of choice for new construction in the United States also. Fiber cement siding can also be painted and can be made to look like wood. Its one significant disadvantage is that the fiber cement planks used in the siding are relatively heavy and need to be placed one at a time. Any method of making their alignment easier is, therefore, of great practical utility. [0004] On the other hand vinyl and other types of building siding remain common and insulation at the times of high energy costs has become an important consideration. Therefore, there is a need of insulation practical to use with vinyl and other types of building sidings as well as fiber cement siding. [0005] The system and method of this invention provide both increased thermal insulation and significantly simple installation of the insulation. Furthermore the invention provides an alignment of the fiber cement planks when fiber cement siding is used. The simplified insulation does not compromise the thermal insulation but makes the system more affordable and time saving. DESCRIPTION OF THE RELATED ART [0006] The relevant patent literature involving siding alignment and insulation products and processes include: [0007] U.S. Patent Publication Number 2009/0019814 is directed to a panelized cladding system including a plurality of battens securable to a building structure, each batten having a structure engaging surface and an integrally formed finish ready panel supporting surface. Fiber cement cladding panels are secured to or through the battens such that the finish ready panel supporting surface of each batten forms an external recessed surface of an expressed joint formed thereon. [0008] U.S. Pat. No. 6,418,610 relates to a method for using a support backer board system and siding. The support backer board system comprises at least a first layer. The first layer is made from a material selected from the group consisting of alkenyl aromatic polymers, polyolefins, polyethylene terephthalate, polyesters, and combinations thereof. The board system is thermoformed into a desired shape with the desired shape being generally contoured to the selected siding. The siding is attached to the board system so as to provide support thereto. In one process, the siding may be vinyl. [0009] U.S. Pat. No. 8,091,313 discloses an apparatus and method for a drainage system of an exterior wall of a building comprising insulation having a rear face for contact with the exterior wall of the building and a drainage plane positioned on the rear face for removal of water from the exterior wall. [0010] CA 2,742,046 discloses an insulation system for securing cladding to the exterior surface of a building. An insulated panel has a front face and a rear face. Joining elements are defined in horizontal edges of the panel for connecting adjacent panels to each other. A horizontal attachment member, such as a nailing hem, is mounted to the rear face of the panel for attaching the insulated panel to the exterior surface. Receiving members are present on the front face of the panel, and can be located in receiving channels. The receiving member is generally made from a material that is better at retaining fasteners, such as nails, than the material of the insulated panel itself. [0011] U.S. Pat. No. 7,762,040 discloses a method for installing siding panels to a building including providing a foam backing board having alignment ribs on a front surface and a drainage grid on a back surface and then establishing a reference line at a lower end of the building for aligning a lower edge of a first backing board an tacking thereon. The system includes tabs and slots along vertical edges of the foam backing board to align and secure adjacent backing boards to each other. A siding panel is butted against one of the lower alignment ribs and secured thereto. Another siding panel is butted against and secured to the adjacent alignment rib to form a shadow line between the adjacent siding panels on the building. [0012] U.S. 20100251648, 2011021073, 20110271622, and US20110271624 disclose foam backing panels for use with lap siding and configured for mounting on a building. The foam backing panels comprise a rear face configured to contact the building, a front face configured for attachment to the lap siding, alignment means for aligning the lap siding relative to the building, means for providing a shadow line, opposing vertical side edges, a top face extending between a top edge of the front face and rear face and a bottom face extending between a bottom edge of the front face and rear face. [0013] The existing art does not provide sufficient protection against moisture drainage of building structures, sufficient aeration between the building surface and the insulation, nor a method or means to easily align drainage panels or attach the insulation boards. [0014] Various implements are known in the art, but fail to address all of the problems solved by the invention described herein. One embodiment of this invention is illustrated in the accompanying drawings and will be described in more detail herein below. SUMMARY OF THE INVENTION [0015] The present invention relates to an apparatus that forms an insulating barrier behind building siding. The siding may be of any material, vinyl siding, wood siding, fiber cement siding or any other siding material. [0016] In U.S. patent application Ser. No. 13/029,336 and corresponding provisional application 61/305,255, the contents of both of which are incorporated herein by reference, the inventor provided an easy to install shaped insulation board with a separate two sided water drainage panel. The inventor has now developed the product further, and provides here an insulation board that in it self may act as two sided water drainage panel and simultaneously allows aeration between the board and the building surface. [0017] According to one preferred embodiment the siding is fiber cement siding and the insulation also acts as an installation guide that aids in attaching fiber cement planks or boards that form the siding. [0018] In a preferred embodiment, a rectangular insulating board made of a suitable thermal insulating material has a substantially flat, rectangular back surface including multiple drainage areas for water draining. [0019] The substantially flat back surface of the insulation board has a plurality of molded drainage areas. The drainage areas consist of vertically positioned drainage grooves and ridges and the drainage areas are separated from each other by inner stud ridges that are designed to coincide with the building studs for attachment of the board. The inner stud ridges may also be designed to be higher than the drainage ridges, whereby the system leaves an aeration space between the drainage areas and building surface when the board is attached on the building studs. [0020] The front surface has preferably one or more stud marking areas. The stud marking areas may contain vertically running stud marking grooves that may also act as water drainage channels but also enable easy lining of the boards plus guide attachment to the studs. The stud marking areas may contain other markings for attachment to the studs as well, such a nail spots, letters, numbers, or color codes. [0021] The front surface may be shaped to form a number of flat-faced, protruding horizontal ridges. The protruding ridges are preferably aligned substantially parallel to an edge of the rectangle. A cross-section, taken orthogonal to the alignment of the protruding ridges, has a saw-tooth shape. The front side of the board also includes means to guide attachment to the building studs. [0022] The protruding horizontal ridges are shaped and sized so that the following may be done. A standard-size, fiber cement plank, or board, may be placed face-down on a long face of a protruding ridge of the shaped insulating board. The fiber cement board may be positioned to have its long edge abutting the short face of an adjacent protruding ridge. A second fiber cement board of a similar size may then be placed face-down on a long face of the adjacent protruding ridge. When the second fiber cement board is positioned to have its long edge abut the short face of the next adjacent ridge, the second board may then overlap the first fiber cement board. The overlap is such that the underside face of the overlap of the second board lies flat on the upper face of the first board. The invention of this disclosure also comprises shaped flashing elements that are sandwiched between the insulation board and the fiber cement boards to provide water protection in areas where two insulation boards are abutting either horizontally or vertically. The shaped insulating board is aligned on the wall to a required orientation. The required orientation is preferably the orientation in which the protruding ridges are aligned in the same direction as the desired orientation of the length of the fiber cement board when it is attached. [0023] An aspect of the instant invention in addition to provide a guidance system for installation of the cement boards is to provide an insulation board that allows efficient water drainage and aeration. Furthermore, the instant invention not only provides guidance for installing the cement boards, but provides guidance to easily align the drainage channels and to attach the insulating boards on the building studs. [0024] Once the shaped insulating board is attached to the wall, it may then serve as a guide for positioning the fiber cement board. The fiber cement board may be positioned by abutting its long side against a short edge of one of the protruding ridges, with the fiber cement board's face against the long face of an adjacent protruding ridge. The fiber cement board is then correctly aligned and may be slid along the ridge edge until it is in place for attaching to the wall. The attachment may, for instance, be by means of a fastener such as, but not limited to, nails, screws, bolts or some combination thereof. [0025] Therefore, the present invention succeeds in conferring the following, and others not mentioned, desirable and useful benefits and objectives. [0026] It is an object of the present invention to provide a shaped insulating board for attachment on building studs, having a vertical cross section, a horizontal cross section, a front surface and a substantially flat back surface, wherein the back surface is forming a molded drainage panel, said drainage panel comprising a multitude of drainage areas, each drainage area being formed by vertical drainage ridges and drainage grooves, and each drainage area being separated from each other by an inner stud ridge, said vertical ridges and grooves running from an upper end of the back surface to a lower end of the back surface, and said stud ridges located from each other at distance such that a multiplication of the distance equals to the distance between building studs, whereby each building stud coincides with one stud ridge, and the front surface comprising markings for attachments on building studs, said markings coinciding with stud ridges on the back surface. [0027] It is another object of the present invention to provide fiber cement siding system comprising: a multitude of fiber cement boards; a shaped insulating board, having a vertical cross section, a horizontal cross section, a shaped front surface and a substantially flat back surface, the front surface being formed of horizontally aligned ridges having a short face and a long face, the short face of one ridge being joined in an angle to the long face of an adjacent ridge, whereby the vertical cross section has a substantially saw tooth like edge toward the front surface and a flat edge toward the back surface, the front surface further comprising a plurality of stud marking areas, each stud marking area consisting of vertically oriented stud marking grooves running across the horizontally aligned ridges from an upper end of the front surface to a lower end of the front surface, said vertically oriented grooves being separated from each other by an outer stud ridge, and the stud marking areas being separated from each other by clearance ridges, said clearance ridges having a width equaling to a distance between building studs, the back surface having a molded drainage panel, said drainage panel comprising a multitude of drainage areas, each drainage area being formed by vertical drainage ridges and drainage grooves, and each drainage area being separated from each other by an inner stud ridge, said vertical ridges and grooves running from an upper end of the back surface to a lower end of the back surface, and said inner stud ridge coinciding with the outer stud ridge, whereby the horizontal cross section of the insulating board has non grooved stud ridge areas in between of grooved drainage areas, and said non grooved stud ridge areas locate from each other at distance equaling to the distance between building studs; and a multitude of flashing elements, said flashing elements consisting of a first rectangle having a short edge substantially equal in length to the width of the short face of the protruding ridge of the front surface of the shaped insulating board, a second rectangle having a long edge longer than the long face of the protruding ridge of the shaped insulating board, and a short edge having a length substantially equal to a long edge of the first rectangle, and wherein the long edge of the first rectangle forms a substantially contiguous join with the short edge of the second rectangle in an angle matching the angle of the joint of the short and the long face of adjacent protruding ridges of the front side of the shaped insulating board. [0028] It is an object of the present invention to provide a thermal insulation including an efficient drainage system. [0029] It is another object of the present invention to provide thermal insulation with drainage panels that allows proper aeration between the insulation and the building surface. [0030] It is a further object of the present invention to provide a system to align the drainage channels of abutting insulation boards. [0031] Another object of the present invention is to easily enable attachment of the insulation board onto the building studs. [0032] It is an object of the present invention to provide additional thermal insulation to houses. [0033] It is an object of the present invention to prevent water damage to building structures. [0034] It is another object of the present invention to provide a tool for rapid positioning of fiber cement boards. [0035] Yet another object of the present invention is to provide quicker, and therefore less expensive, installation of fiber cement siding. BRIEF DESCRIPTION OF THE DRAWINGS [0036] FIG. 1 shows an isometric view of a preferred embodiment of a shaped insulating board of the present invention. [0037] FIG. 2 shows a vertical cross-sectional view of a preferred embodiment of a shaped insulating board of the present invention. [0038] FIG. 3A shows a horizontal cross-sectional view of a preferred embodiment of a shaped insulating board of the present invention. [0039] FIG. 3B is an enlarged detail of the grooves and ridges on the cross section shown in FIG. 3A . [0040] FIG. 4 A. shows an isometric view of the substantially flat back surface of one embodiment of the shaped insulating board of the present invention having a series of drainage areas separated by stud ridges. The vertical cross section in this embodiment is saw tooth like. [0041] FIG. 4 B shows an isometric view of the substantially flat back surface of another embodiment of the shaped insulating board of the present invention having a series of drainage areas separated by stud ridges. The vertical cross section in this embodiment is not saw tooth like. [0042] FIG. 5 shows an isometric view of a shaped flashing element of the present invention. [0043] FIG. 6 shows an isometric view of shaped flashing elements placed to cover a horizontal gap between two adjacent shaped insulating boards. [0044] FIG. 7 shows an isometric view of shaped flashing elements sandwiched between fiber cement boards and shaped insulating board and covering a vertical gap between two adjacent shaped insulating boards. DESCRIPTION OF THE PREFERRED EMBODIMENTS [0045] The preferred embodiments of the present invention will now be described with reference to the drawings. Identical elements in the various figures are identified with the same reference numerals. [0046] Reference will now be made in detail to embodiments of the present invention. Such embodiments are provided by way of explanation of the present invention, which is not intended to be limited thereto. In fact, those of ordinary skill in the art may appreciate upon reading the present specification and viewing the present drawings that various modifications and variations can be made thereto. [0047] FIG. 1 shows an isometric view of a preferred embodiment of a shaped insulating board of the present invention. FIG. 1 shows the shaped insulating board 100 , the front surface 155 , the upper end of the front surface 156 , the lower end of the front surface 157 , the back surface 200 , the upper end of the back surface 202 , the lower end of the back surface 204 , protruding ridges of the front surface 150 , vertical stud marking areas 190 , the front surface, stud marking grooves 192 , clearance ridge 196 between the stud marking areas, outer stud ridge 195 separating the stud marking grooves 192 , and markings for attachment 198 on the outer stud ridges. [0048] FIG. 2 shows a vertical cross-sectional view of a preferred embodiment of a shaped insulating board of the present invention. The figure shows the shaped insulating board 100 , the front surface 155 , the back surface 200 , and the saw-tooth shaped vertical cross section 160 . The long face of protruding ridges 185 and the short face of the protruding ridges are also shown. [0049] FIG. 3 A shows a horizontal cross-sectional view of a preferred embodiment of a shaped insulating board of the present invention. The figure shows the building studs 125 , the building surface 105 , the horizontal cross section 170 , the back surface 200 , the front surface 155 , the stud marking grooves 192 , the outer stud ridge 195 , the clearance ridges 196 between the stud marking areas, the drainage areas 300 , the inner stud ridges 305 , the drainage grooves 310 , and the drainage ridges 320 . [0050] FIG. 3B shows an enlarged detail of the horizontal cross-section of the shaped insulating board of FIG. 3A . The figure shows the back surface 200 , the front surface 155 , the stud marking grooves 192 , the inner stud ridge 195 , the clearance ridge 196 , drainage groove 310 , drainage ridge 320 and inner stud ridge 305 . [0051] FIG. 4 A shows an isometric view of the back surface with stud markings according to one embodiment. The figure shows the back surface 200 , the vertical saw tooth like cross section 160 , the horizontal cross section 170 , the drainage areas 300 , the drainage grooves 310 , the drainage ridges 320 and the inner stud ridges 305 . [0052] FIG. 4 B shows an isometric view of the back surface with stud markings of another embodiment where the front side does not have the protruding ridges and accordingly the vertical cross section is not saw tooth like. The figure shows the back surface 200 , the vertical cross section 160 , the horizontal cross section 170 , the drainage areas 300 , the drainage grooves 310 , the drainage ridges 320 , an optional diagonal groove 303 , and the inner stud ridges 305 . [0053] FIG. 5 shows an isometric view of a shaped flashing element of the present invention. The figure show the flashing element 420 , the first rectangle 440 , the second rectangle 450 , the long edge of the second rectangle 455 , the short end of the second rectangle 460 , the short end of the first rectangle 442 , and the long end of the first rectangle 445 . [0054] FIG. 6 shows the shaped flashing elements placed to cover a horizontal gap between two adjacent shaped insulating boards. The figure shows the horizontal gap 500 between the boards, the flashing element 420 , the first rectangle 440 , the second rectangle 450 , the short end of the first rectangle 442 , the long end of the first rectangle 445 , the long end of the second rectangle 455 , the short end of the second rectangle 460 , the protruding ridges of the front surface 150 , the long face of protruding ridges 185 , and the short face of protruding ridges 180 . [0055] FIG. 7 shows the flashing elements sandwiched between fiber cement boards 110 and shaped insulating board 100 and covering a vertical gap 550 between two adjacent shaped insulating board. The figure shows the vertical gap 550 , fiber cement boards 110 , flashing element 420 , the first rectangle 440 , the second rectangle 450 , the long end of the first rectangle 445 , the short end of the first rectangle 442 , the long end of the second rectangle 455 , the short end of the second rectangle 460 , the protruding ridges of the front surface 150 , the long face of protruding ridges 185 , and the short face of protruding ridges 180 . [0056] Now referring to FIGS. 1 and 2 , the shaped insulating board 100 has a rectangular, substantially flat back surface 200 . In one preferred embodiment the vertical cross section 160 is saw tooth—like and on the front surface 155 , the shaped insulating board 100 is shaped to have a series of substantially identical, flat-faced protruding ridges 150 . The size and shape of these protruding ridges 150 is largely defined by the dimensions of the standard fiber cement boards 110 typically used for exterior wall siding, for instance, on domestic houses. Further, the front surface 155 of the shaped insulating board 100 has vertical stud marking areas 190 . A stud marking area 190 consists preferably of two vertically running stud marking grooves 192 separated by an outer stud ridge 195 . Alternatively, only one stud marking groove 192 may be used. It is also possible to have more than two stud marking grooves. A skilled artisan would understand that it is in the spirit of this invention to have an insulating board where the front surface does not have the protruding ridges 150 but only the stud marking areas (shown in FIG. 4B ). Such a board would be practical to use for example with vinyl—or wood sidings. The width of the outer stud ridges 195 when measured from the middle of one stud marking groove 192 to middle of the second stud marking groove 192 , is determined by the width of the building studs 125 and is between 1 and 4 inches, preferably between 1 and 2 inches, and most preferably 1.5″ (3.81 cm), but the width may also be larger or smaller. The stud marking areas 190 are separated by clearance ridges 196 . The width of the clearance ridge 196 is determined by the distance between building studs 125 . The standard distance between building studs is 16 or 24 inches (40.64 or 60.96 cm) from stud center to stud center. Accordingly, in the preferred embodiment the width is such that a multiplication of the width would equal with the distance between building studs. In a most preferred embodiment the with of the clearance ridges 196 is 2, 4, 8, 16, or 24 inches, whereby there is always one stud ridge 195 coinciding with each building stud 125 and therefore guide installation of the shaped insulating board 100 . One skilled in the art would appreciate that it is within the scope of this invention to vary the width of the clearance ridges long as there is one stud ridge 195 coinciding with each building stud 125 . According to a preferred embodiment the width of the clearance ridges is 16 inches for buildings where the distance between studs is 16 inches, and 24 inches where the distance between the studs is 24 inches. The stud marking areas 190 of the instant invention also helps aligning horizontally abutting insulation boards so that drainage areas and drainage grooves on the back side of the boards are aligned. Furthermore the stud marking areas 190 enable to position the insulation boards 100 so that they are easy to attach with nails or other means to the studs 125 . According to one preferred embodiment, the outer stud ridges 195 have markings for the attachment 198 . In the embodiments where the width of the clearance area is smaller than the distance between the studs, the markings for attachment 198 are so designed that they locate only on those stud ridges that are to be attached to the studs. The markings may be, but are not limited to spots, lines, crosses, colored areas or other codes. According to one embodiment the front of the board may have letters or numbers and certain numbers or letters serve as markings for attachment 198 . Certain codes may guide attachment to studs that are 16 inches apart from each other, while other codes may guide attachment to studs 24 inches apart from each other. According to one embodiment the codes may be letters which may be part of advertisement or other information. [0057] Now referring to FIGS. 4 A and B, the back surface 200 of the shaped insulating board has several drainage areas 300 , each drainage area comprising several vertical drainage grooves 310 separated by drainage ridges 320 . The drainage areas 300 are separated from each other by inner stud ridges 305 . FIG. 4 A shows an embodiment where the front surface has the protruding ridges whereby the vertical cross section 160 is saw tooth like. FIG. 4 B shows another embodiment where the front surface does not have the protruding ridges and the vertical cross section 160 accordingly does not have the saw tooth like character. FIG. 4B also shows a diagonal groove 303 . According to one embodiment the inner stud ridge 305 may contain one or more diagonal grooves 303 connecting the drainage areas. [0058] Referring now to FIGS. 3A and 3B , the inner stud ridges 305 preferably coincide in location with the outer stud ridges 195 , thereby the inner stud ridge and the corresponding outer stud ridge form a non grooved stud area 302 and the non grooved stud areas coincide with the location of the building studs 125 . When the shaped insulating boards are attached to the building they can be easily attached along the non grooved stud areas 302 to the studs 125 for example with nails, screws or other similar means. As is shown in FIG. 3B , which shows the stud area 302 in details, it can be seen that the inner stud ridge 305 is preferably higher than the drainage ridges 320 . This feature would allow an air space between the building surface 105 and the installed shaped insulating board 100 , because the lower height of drainage ridges 320 would not allow them to touch the building surface 105 when the higher inner stud ridges 305 is aligned along and attached to the building studs 125 . According to a preferred embodiment the height a drainage ridge 320 when measured from the bottom of adjacent drainage groove 310 to the top of the inner drainage ridge 320 is between 1/16 and ¼ inches, more preferably about ⅛ inches and most preferably ⅛ inches (3.18 mm). An inner stud ridge 305 may be 1/16 to ¼ inches higher than the drainage ridge, but preferably is 1/16 inches higher than the drainage ridge 320 . Accordingly, preferably when the height of an inner drainage ridge 320 is measured from the bottom of a drainage grove 310 to the top of the inner drainage ridge 320 , it would be 3/16 inches (4.76 mm) high, and the air space between the building surface 105 and the shaped insulating board 100 would be approximately 1/16 inches (1.18 mm). It is understood by a skilled artisan that the measures may be changed without departing the spirit of the invention. [0059] According to one embodiment the board may contain one or more diagonally positioned grooves 303 across the inner stud ridge. Such diagonal grooves may connect the drainage grooves that locale on both sides of the inner stud ridge. Such an embodiment would provide improved water drainage. [0060] The cross section of the stud marking grooves 192 and the drainage grooves 310 is preferably V-shaped, but it can also be U-shaped, or partially square shaped. [0061] The shaped insulating board 100 may be made from any suitable thermal insulation that is also sufficiently rigid to support standard-sized fiber cement boards 110 during installation. [0062] Suitable materials are insulation such as, but not limited to, polyolefin, polyethylene terephithalate, polyester, alkenyl aromatic polymer, polystyrenic resin and polystyrene, or some combination thereof. Preferably the insulation board is made of polystyrene foam. The board may be up to 2″ (5.08 cm) thick. The size of the boards may vary. According to one preferred embodiment the board is about 4×4 feet (121×121 cm), but any other feasible size is within the scope of the invention. [0063] The shaped insulating board 100 with the optional flat faced protruding ridges, stud markings and drainage areas is preferably shaped by using molding techniques but may be shaped by any method suitable to the material used including hot wire forming techniques such as, but not limited to preformed wire manufacture. [0064] Now referring to FIGS. 5 , 6 and 7 , the instant invention comprises a shaped flashing element 420 to waterproof the horizontal 500 and vertical 550 gaps that are between adjacent shaped insulating boards 100 . According to a preferred embodiment the shaped flashing element 420 is made of coated aluminum, but instead of aluminum other malleable materials such as copper, bronze, tin, or steel may also be used. The flashing element may also be made of plastic or polyethene. Preferably the flashing element is made of aluminum coated with an anticorrosion coating from both sides to avoid corrosion caused by the fiber cement. The shaped flashing element 420 may, for instance, be made by a process such as, but not limited to, molding, machining, bending or some combination thereof. [0065] FIG. 5 illustrates the flashing element according to a preferred embodiment. The flashing element 420 has a first rectangle 440 and a second rectangle 450 . The first rectangle 440 has a short edge 442 substantially equal in length to the width of the short face 180 of the protruding ridge 150 . The second rectangle 450 has a long edge 455 . The long edge 455 may be substantially equal in length to the width of the long face 185 of the protruding ridge 150 of the shaped insulating board 100 , but according to a preferred embodiment the long edge 455 is longer than the width of the long face 185 . According to a most preferred embodiment the long edge 455 is substantially equal in length to the width of the cement board 110 . The short edge of the second rectangle 460 has a length substantially equal to the long edge of first rectangle 440 . The long edge of the first rectangle 442 forms a substantially contiguous join with the short edge of the second rectangle 450 in an angle that matches the angle between adjacent protruding ridges 150 of the shaped insulating board 100 . [0066] FIG. 6 shows an isometric view of shaped flashing elements 420 placed to cover a horizontal gap 500 between two adjacent shaped insulating boards 100 . FIG. 7 shows an isometric view of shaped flashing elements 420 placed to cover a vertical gap 550 between adjacent shaped insulation boards 100 . As shown in FIGS. 6 and 7 , the next step after attaching the shaped insulation board 100 on the building surface is a sandwich flashing elements between the insulation board 100 and the fiber cement boards 110 to cover horizontal 500 or vertical 550 gaps between two adjacent insulation boards 100 . Once the fiber cement boards 110 are secured, the shaped flashing element 420 is held in place without any fastening elements. An advantage in this is to save material and on the other hand to save the flashing elements from any holes that would be created by nails or pins or other fastening means. [0067] In a preferred embodiment, the shaped flashing element 420 may have a width in a range of 0.5 to 12 inches (1.27 cm to 30.48 cm) and a thickness in a range of less than 0.5 inches (1.28 cm). More preferably, the shaped flashing element 420 may have a width in a range of 1 to 3 inches (2.54 to 7.62 cm) and a thickness in a range of less than 0.125 inches (3.18 mm). According to a preferred embodiment the long edge of the second rectangle 455 is preferably between 5 and 8 inches (12.70 to 20.32 cm), but the length primarily depends on the width of the fiber cement planks. [0068] According to one embodiment of this invention, a water proof sheet may be attached on the building surface 105 before attaching the shaped insulating boards 100 . Such water proof sheet may be made of any suitable waterproof or water-resistant for creating a vapor barrier such as, but not limited to, aluminum foil, paper-backed aluminum, polyethylene plastic sheet, a metalized film, or some combination thereof. [0069] Although this invention has been described with a certain degree of particularity, it is to be understood that the present disclosure has been made only by way of illustration and that numerous changes in the details of construction and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention.

A shaped insulating board is disclosed for enabling lining of fiber cement boards and simultaneously enabling attachment of the insulating board on the building studs. Furthermore, the shaped insulating board provides a water drainage panel that allows water to drain downward on both sides of the board. The shaped insulating board also provides aeration between the board and the building surface.

TECHNICAL FIELD The invention relates generally to a redriver and, more particularly, to a redriver for a bus interface. BACKGROUND For the standards for Peripheral Component Interface Express (PCIe) version 2.7 (dated Jan. 15, 2007) and Universal Serial Bus (USB) version 3.0 (dated Nov. 17, 2008), each protocol provides seamless mechanisms to detect cable connections, which is accomplished through the use a receive or RX detect feature. However, the Serial Advanced Technology Attachment (SATA) revision 2.6 standard (which dated Mar. 7, 2007 and which is incorporated by reference for all purposes) does not specify any way to detect cable attachment or detachment for either cabled or socket applications. This deficiency poses a disadvantage for mobile applications (i.e., notebook personal computers (PCs)) that support an external-SATA (eSATA) port. Turning to FIG. 1 , an example of a conventional system 100 can be seen. System 100 generally comprises a host system 102 that communicates with an external device 104 (i.e., a hard disk drive) through a SATA compliant cable 106 . To accomplish this, cable 106 is coupled to an external-SATA (eSATA) compliant connector 108 , and a redriver 110 (such as the Texas Instruments Incorporated's SN75LVCP412) provides communications between connector 108 and SATA host 112 over communication link 114 . With this configuration and when the external device 104 is disconnected or detached, host 112 continuously sends communication reset signals (or out-of-band signals) to initiate a response from the external device 104 , which may be connected at any time. Needless to say, the nearly continuous transmission of the communication reset signals from the host can waste a considerable amount of power. To address this solution, at least in part, the SN75LVCP412 from Texas Instruments Incorporated uses an Auto Low Power (ALP) Mode. In particular, this ALP mode is entered when there is not differential transaction or the link to the external device is in an electrical idle state. However, this redrive, like many other redrivers, only addresses power consumption by the redriver; the host may continue to use power through the transmission of communication reset signals. Therefore, there is a need for a method and/or apparatus that performs cable detection and reduces power consumption. SUMMARY A preferred embodiment of the present invention, accordingly, provides an apparatus. The apparatus comprises a first data terminal that is adapted to be coupled to an external device; a second data terminal that is adapted to be coupled to a host; a cable disconnect terminal that is adapted to be coupled to a host; a driver that is coupled to input terminal and the output terminal; a detector that is coupled to the driver; and a controller that is coupled to the detector and the cable disconnect terminal, wherein the controller determines whether the external device is coupled to the first data terminal, and wherein the controller issues a cable disconnect signal through the cable disconnect terminal to disable the host if the external device is not coupled to the first data terminal. In accordance with a preferred embodiment of the present invention, the driver further comprises a first driver and wherein the controller further comprises: a first logic circuit that receives an open detect signal; a first delay line that is coupled to the first logic gate; a second delay line that is coupled to the first logic gate; a second logic circuit that is coupled to the first delay line and the second delay line, wherein the second logic circuit is clocked by the second delay line; a reset circuit that is coupled to the second logic circuit; and a second driver that is coupled to the second logic circuit and to the cable disconnect terminal. In accordance with a preferred embodiment of the present invention, the first logic circuit is an AND-gate that receives the open detect signal and an enable signal. In accordance with a preferred embodiment of the present invention, the second logic circuit is a D-flip-flop having an input terminal, a clock terminal, and a preset terminal, wherein the input terminal of the D flip-flop is coupled to the first delay line, and wherein the clock terminal is coupled to the second delay line, and wherein the pre-set terminal is coupled to the reset circuit. In accordance with a preferred embodiment of the present invention, the second delay line further comprises a plurality of inverters coupled in series with one another. In accordance with a preferred embodiment of the present invention, the first delay line further comprises an inverter. In accordance with a preferred embodiment of the present invention, the reset circuit further comprises: a timer that receives a power-on-reset signal; a third logic circuit that receives the enable signal and a preset signal and that is coupled to the timer; a third delay line that is coupled to the third logic circuit; a fourth logic circuit that receives a return signal and the preset signal; a fifth logic circuit that is coupled to the third delay line and the third logic circuit; and a sixth logic circuit that is coupled to the is coupled to the fourth logic circuit, the fifth logic circuit, and the preset terminal of the D flip-flop. In accordance with a preferred embodiment of the present invention, the AND-gate further comprises a first AND-gate, wherein the first and second terminals are differential, and wherein the apparatus further comprises an equalizer that is coupled between the first terminal and the driver, and wherein the third logic circuit further comprises a NAND-gate, and wherein the fourth logic circuit further comprises a second AND-gate, and wherein the fifth logic circuit further comprises and OR-gate, and wherein the sixth logic circuit further comprises a third AND-gate. In accordance with a preferred embodiment of the present invention, an apparatus is provided. The apparatus comprises a host; a connector that is adapted to be coupled to an external device; and a redriver having: a first pair of differential data terminals that are coupled to the connector; a second pair of differential data terminals that are coupled to the host; a third pair of differential data terminals that are coupled to the connector; a fourth pair of differential data terminals that are coupled to the host; a cable disconnect terminal that coupled to the host; a first equalizer that is coupled to the second pair of differential input terminals; a first driver that is coupled to the first equalizer and the first pair of differential input terminals; a second equalizer that is coupled to the third pair of differential input terminals; a second driver that is coupled to the second equalizer and the fourth pair of differential input terminals; a first detector that is coupled to the first driver; a second detector that is coupled to the second driver; and a controller that is coupled to the detector and the cable disconnect terminal, wherein the controller determines whether the external device is coupled to the first data terminal, and wherein the controller issues a cable disconnect signal through the cable disconnect terminal to disable the host if the external device is not coupled to the first data terminal. The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and the specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which: FIG. 1 is a block diagram of a conventional system; FIG. 2 is a block diagram of an example of system in accordance with a preferred embodiment of the present invention; FIG. 3 is a block diagram of an example of the redriver of FIG. 2 ; FIG. 4 is a block diagram of a portion of the controller of FIG. 3 ; and FIG. 5 is a flow chart depicting an example of at least a portion of the operation of the redriver of FIG. 2 . DETAILED DESCRIPTION Refer now to the drawings wherein depicted elements are, for the sake of clarity, not necessarily shown to scale and wherein like or similar elements are designated by the same reference numeral through the several views. Turning to FIGS. 2-4 , a system 200 in accordance with a preferred embodiment of the present invention can be seen. System 200 is similar to system 100 , except that host 202 includes a redriver 204 , which is able to provide a cable disconnect signal over cable disconnect link 204 . The redriver 204 generally comprises a two channel SATA (rev. 2.6) compliant redriver that supports data rates up to 3.0 Gbps. Each of the channels of the redriver 204 generally comprises a pair of differential input terminals RX 1 P/RX 1 M or RX 2 P/RX 2 M, a pair of differential output terminals TX 1 P/TX 1 M or TX 2 P/TX 2 M, an equalizer 302 - 1 or 302 - 2 , a driver 304 - 1 or 304 - 2 , a detector 306 - 1 or 306 - 2 , and a controller 308 . Using the first channel as an example, in operation, a signal is received through its input terminals RX 1 P/RX 1 M, equalized by equalizer 302 - 1 , and driven by driver 304 - 1 . Additionally, for the first channel, detector 306 - 1 (which operates as a return squelch detector) enables full detection of out-of-bounds signals (i.e., amplitude of the received signal is lower than a predetermined threshold). Of interest, however, is the controller 308 . Controller 308 is able to determine whether external device 104 is coupled to connector 108 , and when there is no connection present, the controller 308 can issue a cable disconnect signal through the cable disconnect terminal CD (which is generally coupled to the cable disconnect link 206 ). To accomplish this, controller 308 preferably uses a D flip-flop 408 , an AND-gate 410 , and driver 412 , where the flip-flop is generally controlled by an input circuit and a reset circuit. The input circuit generally comprises an AND-gate 402 that receives an enable signal EN and an internal cable disconnect signal OPENDET (which can be provided detector 306 - 1 or 306 - 2 ) and delay lines 404 and 406 . Typically, delay line 404 (which generally comprises an inverter) provides a signal to the D or input terminal of flip-flop 408 , while delay line (which generally comprises a several inverters coupled in series with one another and which is generally longer than delay line 406 ) provides a clocking signal to the clocking input of flip-flop 408 . The reset circuit generally comprises a timer 414 (which is about 10 ms and that receives a power-on reset signal POR), an NAND-gate 416 (which is coupled to the timer 414 and receives the enable signal EN and preset signal PS), delay line 408 (which generally comprises a several inverters coupled in series with one another), an AND-gate 420 (which receives an inverted squelch return signal RETURN and the preset signal PS), an OR-gate 422 (which is coupled to NAND-gate 416 and delay line 418 and receive an inverted enable signal EN and an inverter preset signal PS), and AND-gate 424 (which is coupled to OR-gate 422 , AND-gate 420 , and the preset terminal of flip-flop 408 ). When the internal cable disconnect signal OPENDET transmitted to controller 308 is logic high or “1” (and the enable signal EN is logic high or “1”), AND-gate 402 outputs a “1” to delay lines 404 and 406 . Because delay line 404 is typically shorter than delay line 406 , the output from AND-gate 402 transmitted through delay line 404 reaches the D flip-flop 408 prior to the output from AND-gate 402 transmitted through delay line 406 . Once the output from AND-gate 402 transmitted through delay line 406 reaches the flip-flop 408 , a logic high or “1” is output to AND-gate 410 , and since the enable signal EN is “1”, AND-gate 410 outputs a “1.” This output from AND-gate 410 is driven by driver 412 and is provided to terminal CD. This “1” presented at terminal CD reflects a detection that external device 104 is not present or the link is idled. Turning now to FIG. 5 , a flow chart depicting a least a portion of the operation of redriver 204 can be seen. At power-up, a determination is made in step 504 as to whether the preset signal PS (which is generally provided through a preset terminal) is “1”, which indicates whether the cable detect is active. If the preset signal PS is “0” (cable is inactive), then the redriver 204 enters an ALP mode in step 506 . Alternatively, if the preset signal PS is “1” (cable is active) at power-up, then redriver 204 enters an indeterminate state in step 502 , where the terminal CD can present a “1” (step 510 ) or a “0” (step 514 ). From this indeterminate state, the present signal PS (and its corresponding terminal) are switched to “0” in step 520 , while the redriver 204 (which is generally an integrated circuit or IC) is active, so that the redriver 204 can enter the ALP mode in step 506 . With the redriver 204 in ALP mode, there is periodic checking in step 508 to determine whether the present signal PS is “1.” Once the preset signal PS is “1,” terminal CD is set to present a “0” in step 510 . When terminal CD has been adjusted to present a “0” and external device 104 is present, the initial state is correct, but if terminal CD has been adjusted to present a “0” and external device 104 is missing, then the state is corrected in step 514 by setting terminal CD to present a “1” when a high swing is detected (chirp detect circuit that is generally included in controller 308 determines there is a missing load) in step 512 . If terminal CD is “1” and an external device 114 is present, terminal CD is set to present a “0” in step 510 , and when the return squelch circuit (generally included in detectors 306 - 1 and 306 - 2 ) sets the return signal RETURN to present a “1” in step 516 or when the host transmits a signal in step 518 and a high swing is detected in step 512 . As a result, several advantages can be realized. Redriver 204 uses an eSATA (rev. 2.6) compliant connector without the need for any special, non-compliant adapters. Also, redriver 204 enables host 112 to be powered down or placed in a low power mode so as to reduce power consumption, which can be particularly advantageous for mobile applications where battery life can be extended. Having thus described the present invention by reference to certain of its preferred embodiments, it is noted that the embodiments disclosed are illustrative rather than limiting in nature and that a wide range of variations, modifications, changes, and substitutions are contemplated in the foregoing disclosure and, in some instances, some features of the present invention may be employed without a corresponding use of the other features. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention.

With conventional redrivers used for external Serial Advanced Technology Attachment (eSATA), there is no ability to indicated to a host that an external device (like a hard disk drive) is not present. As a result, power is consumed by a host because of nearly continual transmission of communication reset signals. Here, a redriver has been provided that includes a cable disconnect terminal and circuitry within a controller that is able to detect whether an external device is present. This redriver enables a host to be powered down or placed in a low power mode while also enabling the use an eSATA compliant connector.

CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims the benefit under 35 U.S.C. §119 of Korean Application No. 10-2012-0082105, filed Jul. 27, 2012, which is hereby incorporated by reference in its entirety. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] An exemplary aspect of the present disclosure relates to a motor for a vehicle. [0004] 2. Description of Related Art [0005] In general, a BLDC (Brushless DC) motor is a motor that does away with a brush and a mechanical commutator used in a traditional motor, replacing it with an electronic device that improves the reliability and durability of the unit and generating no mechanical and electrical noise. [0006] A conventional BLDC motor includes a stator mounted with a motor housing and a frame, a magnet rotor rotatably inserted into the stator and an axis inserted and fixed at a center of a rotor. The stator includes a stator core wound with a coil. The stator core is manufactured by punching silicon plates, each having a thickness of 1 mm or less, and stacking the silicon plates. Each silicon plate includes a cylindrical yoke unit, a plurality of tooth units, each protruded at an inner surface of the yoke unit toward a center along a circumferential direction each spaced apart at a predetermined distance, and pole units formed at a distal end of the teeth units, each having a polarity and protruded to both sides. [0007] A plurality of slots wound with a coil is formed between the tooth units, and slot is inserted by an insulator of insulation material to insulate the stator core from the coil. The insulator is so coupled as to be inserted by being sealed from both sides along a laminated direction of the stator core. [0008] Meanwhile, the coil may be wound to correspond to polarity of a use electric power, and may be conductively connected to mutually different terminals of three polarity in a case three (U, V, W) phase electric power is used. [0009] The insulator is integrally provided with a terminal housing coupling unit where a terminal housing for power supply is press-fitted into the terminal housing coupling unit. [0010] In general, in a case the terminal housing and the insulator are injection molded with a synthetic resin material, a large gap is formed between the terminal housing coupling unit and the terminal housing after assembly. In a case a large gap is formed between the terminal housing coupling unit and the terminal housing, it is disadvantageous that the terminal housing may be easily separated from the terminal housing coupling unit when an electric power applying position is assembled. BRIEF SUMMARY [0011] Exemplary aspects of the present disclosure are to substantially solve at least the above problems and/or disadvantages and to provide at least the advantages as mentioned below. Thus, the present disclosure is directed to provide a terminal connection structure of a structure-improved motor configured to accurately assemble a terminal housing to a power supply terminal when a motor is assembled. [0012] In one general broad aspect of the present disclosure, there is provided a motor comprising: an insulator body coupled to a stator core wound with a plurality of coils applied with an electric power having mutually different polarities to prevent the coils and the stator core from being short-circuited; a terminal housing coupling unit integrally constituted with the insulator body, protruded to a circumferential direction and coupled to a terminal housing supplying an external electric power; a terminal housing coupled to the terminal housing coupling unit to supply an electric power to the motor; a fixing unit position-fixing the terminal housing to the terminal housing coupling unit; and a regulation unit mounted on the fixing unit to regulate a rotation angle of the terminal housing. [0013] Preferably, but not necessarily, the fixing unit may include a side guide plate inside the terminal housing, and a hook member on the terminal housing coupling unit. [0014] Preferably, but not necessarily, the guide plate may be protrusively arranged at both distal ends of the terminal housing. [0015] Preferably, but not necessarily, the guide plate may include a hook portion including a through hole having an arc-shaped inner surface at a partial section, and a regulation slit extended from the through hole of the hook portion. [0016] Preferably, but not necessarily, the hook portion may take a shape corresponding to that of the hook member and may be snap-fitted to the hook member. [0017] Preferably, but not necessarily, the hook portion may be greater than the hook member. [0018] Preferably, but not necessarily, the hook member may be protruded to face the side guide plate of the terminal housing coupling unit. [0019] Preferably, but not necessarily, the hook member may include a hook protrusion, an entry unit at a distal end of one side of the hook protrusion and a regulation protrusion extended to one direction of the hook protrusion. [0020] Preferably, but not necessarily, the hook protrusion may take an arc shape at a surface contacting the hook portion. [0021] Preferably, but not necessarily, the regulation protrusion may be straight. [0022] Preferably, but not necessarily, an angle between the regulation protrusion and the regulation slit may be 15°˜25° based on a surface perpendicular to an insertion direction of the terminal housing. BRIEF DESCRIPTION OF THE DRAWINGS [0023] FIG. 1 is a cross-sectional view illustrating a motor according to an exemplary embodiment of the present disclosure. [0024] FIG. 2 is an exploded perspective view illustrating a stator of FIG. 1 . [0025] FIG. 3 is an enlarged view of an essential part of FIG. 2 . DETAILED DESCRIPTION [0026] Now, a motor according to an exemplary embodiment of the present disclosure will be described with reference to the accompanying drawings. [0027] FIG. 1 is a cross-sectional view illustrating a motor according to an exemplary embodiment of the present disclosure, FIG. 2 is an exploded perspective view illustrating a stator of FIG. 1 , and FIG. 3 is an enlarged view of an essential part of FIG. 2 . [0028] The motor according to an exemplary embodiment of the present disclosure includes a motor housing ( 1 ), a stator ( 2 ), a rotor ( 3 ) and a rotation shaft ( 4 ) as illustrated in FIG. 1 . [0029] The motor housing ( 1 ) may be provided in a state of an upper surface being opened, and may be fixed therein by the stator ( 2 ). The motor housing ( 1 ) may come in various shapes depending on the types of motors, and in case of a motor used for a DCT (Dual Clutch Transmission), a pair of motor housings ( 1 ) having a shape as shown in FIG. 1 may be provided. At this time, the opened upper surface of the motor housing ( 1 ) may be arranged with a power output axis connected to or released from the rotation shaft ( 4 , described later) of the motor to selectively receive a power outputted from the rotor ( 3 ). [0030] Unlike the conventional manual transmission vehicle, the DCT contains the traditional elements of a manual and is driven by a twin, or dual clutch module. In the DCT, the clutches operate independently. One clutch controls the odd gears (first, third, fifth and reverse), while the other controls the even gears (second, fourth and sixth). Using this arrangement, gears can be changed without interrupting the power flow from the engine to the transmission. That is, the DCT system works by using a system of twin clutches which shifts gears automatically with the direction of the driver and assistance of a computer. Without a clutch pedal, the DCT system is able to shift faster than a manual, while still allowing more control and power than an automatic transmission. [0031] In general, the DCT includes a dual clutch, a transmission control unit setting each gear shift stage by receiving a power from the dual clutch, a clutch actuator controlling each clutch of the dual clutch, a gearshift actuator performing the gearshift by applying selecting and shifting manipulation to the transmission control unit, and an electronic control unit electronically controlling the clutch actuator and the gearshift actuator by receiving various information including a vehicle speed and shift commands. Thus, the stator ( 2 ) installed at the motor housing ( 1 ) is connected to the output axis of the rotor ( 3 ) by selection operation of the clutch actuator and the power is transmitted to each transmission. [0032] The stator ( 2 ) is provided inside the motor housing ( 1 ), and may be preferably coupled to a cylindrical stator reception unit formed at an inner space of the motor housing ( 1 ) as illustrated in FIG. 1 . The stator ( 2 ) may be formed at a stator core ( 30 ) of metal material for formation of magnetic flux with a plurality of teeth, each tooth wound with a coil, whereby an electric power may be applied to the coil to form a magnetic field. At this time, the stator core having the plurality of teeth may be wound with the coil, while being installed with an insulator thereon, to prevent an electric from flowing thereon. Meanwhile, the number of teeth may be increased or decreased depending on the size and output of the motor. [0033] The rotor ( 3 ) may include a core member ( 3 a ) centrally coupled by the rotation shaft ( 4 ), and a magnetic member ( 3 b ) press-fitted into the core member ( 3 a ). [0034] Referring to FIGS. 2 and 3 , an approximately ring-shaped insulator body ( 10 ) may be installed at an upper surface of the stator core ( 30 ) of the stator ( 2 ). The insulator body ( 10 ) may be integrally provided in one body with a terminal housing coupling unit ( 20 ) so as to be protruded from a distal end thereof. In general, the insulator body ( 10 ) is injection molded with a resin material, such that the terminal housing coupling unit ( 20 ) is preferably injection molded with the same material as that of the insulator body ( 10 ). The terminal housing coupling unit ( 20 ) may be attachably and detachably coupled by a terminal housing (not shown) for connection with a power supply unit (not shown) [0035] Referring to FIG. 2 , the insulator body ( 10 ) may be centrally formed with a plurality of tooth guides, with each tooth guide coupled to match, one on one, the each tooth centrally formed on the stator core ( 30 ). The tooth guides function to prevent the coil wound on the teeth from being short-circuited with the stator core ( 30 ) formed with a conductive material. [0036] In general, the insulator body ( 10 ) is injection molded with a resin material, and the terminal housing coupling unit ( 20 ) may be preferably injection molded with the same material as that of the insulator body ( 10 ). The terminal housing ( 100 ) of the terminal housing coupling unit ( 20 ) may be attachably and detachably coupled by a fixing unit ( 130 ) for connection with the power supply unit (not shown). [0037] The fixing unit ( 130 ) includes a side guide plate ( 110 ) provided on the terminal housing ( 100 ) and a hook member ( 120 ) provided at the terminal housing coupling unit ( 20 ). [0038] The side guide plate ( 110 ) is formed to protrude at both distal ends of the approximately cubic-shaped terminal housing ( 100 ) to an upper side direction on FIGS. 2 and 3 , and may include an arc-shaped hook portion ( 111 ) at a position corresponding to that of the hook member ( 120 ), and a regulation slit ( 112 ) for regulating a rotation angle of the terminal housing ( 100 ). [0039] The side guide plate ( 110 ) is fixed at a terminal housing coupling unit ( 20 ) side integrally formed with the terminal housing ( 100 ) at the insulator body ( 10 ), and a predetermined angle is rotatably provided when the stator ( 2 ) including the insulator body ( 100 is assembled on the housing ( 1 ) and a power terminal ( 150 ) is coupled to a bottom side of the terminal housing ( 100 ), whereby the assembly between the power terminal ( 150 ) and the terminal housing ( 100 ) can be improved in the course of assembly process. [0040] The hook portion ( 111 ) may be provided in the same shape as that of the hook member ( 120 ) to allow the hook member ( 120 ) to be snap-fitted. The hook portion ( 111 ) may be formed larger than the hook member ( 120 ) so that the hook member ( 120 ) can be rotatably assembled inside the hook portion ( 111 ). [0041] The regulation slit ( 112 ) may be formed at a position corresponding to that of a regulation protrusion ( 123 ) formed at the hook member ( 120 ), and the direction and size of the regulation slit ( 112 ) may be variably configured according to design. For example, an angle (α) of the regulation slit ( 112 ), as illustrated in FIGS. 2 and 3 , may be 15°˜25° based on a surface perpendicular to an insertion direction of the power terminal ( 150 ) from a center of the hook portion ( 111 ). [0042] According to an exemplary embodiment of the present disclosure, the angle of the regulation slit ( 112 ) may be at 20° but the angle is not limited thereto, and may be variably formed according to design need. [0043] In a case the regulation slit ( 112 ) is formed as mentioned above, although the angle of the rotating terminal housing ( 100 ) may partially move about the hook member ( 120 ) according to a gap between the hook member ( 120 ), the rotation of the terminal housing ( 100 ) can be regulated, whereby the terminal housing ( 100 ) is prevented from being broken by interference with the housing ( 1 ) in the course of being coupled to the power terminal ( 150 ) while the terminal housing ( 100 ) is inserted into the housing ( 1 ), or too tightly fixed into the housing ( 1 ). [0044] The hook member ( 120 ) is protrusively formed to a direction facing the side guide plate ( 110 ) of the terminal housing coupling unit ( 20 ), and may include a hook protrusion ( 121 ), an entry unit ( 122 ) and a regulation protrusion ( 123 ). [0045] The hook protrusion ( 121 ) may be provided at a rear end of the entry unit ( 122 ). The hook protrusion ( 121 ) is hooked to the hook portion ( 111 ) at a coupling position of the terminal housing ( 100 ) to prevent the terminal housing ( 100 ) from being disengaged from the terminal housing coupling unit ( 20 ).The hook protrusion ( 121 ) is hooked and coupled to the hook portion ( 111 ) formed at the side guide plate ( 110 ), where each contact surface takes an arc shape to allow a round inner surface of the hook portion ( 111 ) to rotatably slide with an external surface of the hook protrusion ( 121 ). [0046] The entry unit ( 122 ) is provided to have a sliding slant surface having a predetermined angle relative to an insertion direction (‘A’ direction of an arrow in FIG. 2 ) of the terminal housing ( 100 ), whereby, in a case the side guide plate ( 110 ) is inserted to a position corresponding to the hook member ( 120 ), the side guide plate ( 110 ) can be elastically deformed to a direction (arrow ‘B’ direction) perpendicular to the insertion direction. [0047] The regulation protrusion ( 123 ) is protrusively formed by being extended to one direction of the hook protrusion, and according to an exemplary embodiment of the present disclosure, the regulation protrusion ( 123 ) may be provided in a shape of a straight lug having a predetermined length as shown in FIGS. 2 and 3 . At this time, the regulation protrusion ( 123 ) may be provided to have a predetermined angle based on a center of the hook member ( 120 ), and according to an exemplary embodiment of the present disclosure, the regulation protrusion ( 123 ) may be provided to have a 20° angle based on a center of the hook member ( 120 ). Thus, the hook protrusion ( 121 ) and the hook portion ( 111 ) are prevented from being unlimitedly rotated by the regulation protrusion ( 123 ). [0048] A center guide plate ( 125 ) is interposed between the hook members ( 120 ) as illustrated in FIG. 2 , to guide an insertion direction during insertion of the terminal housing ( 100 ), and restricts the rotation of the terminal housing ( 100 ) when the terminal housing ( 100 ) is fixed to a coupling position. In a case the center guide plate ( 125 ) is interposed between the insulator body ( 10 ) and the terminal housing ( 100 ), the rotating terminal housing ( 100 ) is prevented from being disengaged while the coil is wound on the insulator body ( 10 ) to enable a tight coupling of the terminal housing ( 100 ). [0049] Furthermore, the center guide plate ( 125 ) is extensively formed to a direction parallel with the insertion direction of the terminal housing ( 100 ) to prevent the terminal housing ( 100 ) from being twisted during insertion of the terminal housing ( 100 ) and to allow the terminal housing ( 100 ) to be inserted to the coupling position. [0050] As apparent from the foregoing, a pivot rotation is possible when the terminal housing ( 100 ) is coupled to the terminal housing coupling unit ( 20 ) during the stator ( 2 ) insertion process to allow the power terminal ( 150 ) of FIG. 2 to be accurately inserted into the assembly position of the terminal housing ( 100 ). [0051] Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims.

A motor is provided, the motor including an insulator body coupled to a stator core wound with a plurality of coils applied with an electric power having mutually different polarities to prevent the coils and the stator core from being short-circuited, a terminal housing coupling unit integrally constituted with the insulator body, protruded to a circumferential direction and coupled to a terminal housing supplying an external electric power, a terminal housing coupled to the terminal housing coupling unit to supply an electric power to the motor, a fixing unit position-fixing the terminal housing to the terminal housing coupling unit, and a regulation unit mounted on the fixing unit to regulate a rotation angle of the terminal housing.

BACKGROUND [0001] 1. Technical Field [0002] The present invention is directed to the field of computer advertising systems. More specifically, the present invention is directed to a computer audio advertising systems. [0003] 2. Description of the Related Art [0004] The Internet provides a myriad of “free” services to its users. Users may search for Internet content using such “free” web sites as Yahoo or Infoseek. People's addresses or phone numbers or map directions are also freely provided on the Internet. Many newspaper web sites can be browsed at no cost. Users have grown accustomed to free services. [0005] Due to a vastly different infrastructure, wireless communication systems have difficulty providing truly free services to its users. To heighten the difficulty, new technologies are continuously emerging to enhance services provided by wireless communication systems. For example, voice markup languages have been introduced that make available the services of the Internet to wireless communication users. One such voice markup language is VoiceXML which permits users to interact with Internet web pages using an audio interface (such as a cellular communication device). [0006] An example of a VoiceXML application is a restaurant locating application with which a user can communicate in order to locate a restaurant in a certain city. Such interaction includes asking the user questions, such as to the type of restaurant and location. Another VoiceXML application may interact with the user to provide directions to the restaurant. The VoiceXML application typically resides on an Internet web site. A telephony server acts as an interface with the web site and allows the VoiceXML application to interact with the user. [0007] The ever increasing sophistication of wireless communication systems as shown by the advent of VoiceXML technology renders it more difficult for such systems to provide “free” services to their users. Users have been exposed by the Internet to free services and expect to have free services with their wireless communication systems. SUMMARY [0008] The present invention satisfies the aforementioned needs of wireless communication users as well as other needs. In accordance with the teachings of the present invention, a computer-implemented audio advertising system provides audio advertisements to users of telephony services. An advertising management server receives audio advertisements and advertisement account data over the network. An advertising database stores the audio advertisements and advertisement account data. Upon requests from the telephony services, an advertising selection and retrieval server fetches audio ads according to a set of effective searching criteria. The retrieved audio ad is played to users of the telephony services. BRIEF DESCRIPTION OF THE DRAWINGS [0009] [0009]FIG. 1 is a block diagram that depicts the advertising management computer system of the present invention; [0010] [0010]FIG. 2 is a block diagram that depicts the advertising selection and retrieval computer system of the present invention; [0011] [0011]FIG. 3 is a block diagram that depicts the revenue sharing system of the present invention; [0012] [0012]FIG. 4 is a flowchart that depicts steps to process an advertising request from an advertiser; and [0013] [0013]FIGS. 5 and 6 are flowcharts that depict steps to process an incoming customer's call in accordance with the teachings of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT [0014] [0014]FIGS. 1 and 2 are system block diagrams that depict the computer-implemented components of the present invention. The present invention manages and selects audio advertisements for use in a telephony environment. Ad recordings and ad edits submitted by advertisers are managed by an advertising management server. An advertising selection/retrieval server provides an appropriate audio ad to an end-user based upon ad selection criteria. [0015] [0015]FIG. 1 depicts the advertising management computer system of the present invention as shown generally at 30 . The advertising management computer system 30 provides for the self-management of audio advertising via telephony servers by providing such features as advertisers defining the relationship for their ad delivery as well as advertisers uploading their own advertising content. [0016] The advertising management server 32 receives ad recordings and ad edits from a telephony server 34 . Advertisers and advertising agencies 36 (i.e., ad providers) are possible sources of these ad recordings and ad edits. The advertising management server 48 provides a set of web user interfaces, network communication ports, and phone user interfaces so that the advertisers and advertising agencies may interact with server 48 . It should be understood that the advertising management server 32 and the advertising retrieval server 48 may operate upon the same computer or operate upon different computers depending upon the application at hand. [0017] The ad recordings may be an audio recording of an ad lasting from several seconds to several minutes. In one embodiment, the advertising management server 32 does not receive from the advertisers 36 the actual audio ad file, but instead an identifier for locating the audio file on a network. The network may be a local area network, a wide area network, or a global network (such as the Internet). An example of an identifier is a Uniform Resource Location (URL) identifier that identifies where on the Internet the audio file is located. It should be understood that the present invention also includes the URL indicating that the location of the audio file is within the advertising database 38 . [0018] Moreover, the format of the audio file may vary greatly. The audio file may be in a WAVE format or some other format, provided that the format is ultimately able to be played to a customer. [0019] The advertising management server 32 stores the ad recording in the advertising database 38 . The advertising management server 32 collects and stores information in addition to the ad recording. Such information includes the identity of the advertiser who stored the ad recording, when the ad recording was stored, the format of the audio file, and profile of customers potentially interested in listening to the ad. [0020] The present invention also collects the type of financial arrangement that is to be associated with the playing of the ad. For example, an advertiser may wish to pay a set amount each time the ad is played to a customer. Another advertiser may wish to pay for the playing of the ad by sharing its revenues with the advertising management server's owner that are attributable to the product being advertised. In still another way, the advertiser may pay a set fee amount regardless of how often the ad is played. In this way, the present invention is highly adaptable to a number of financial arrangements. [0021] The advertising management server 32 also processes modifications or edits to the ad recording information, such as by placing a new ad location identifier that locates the most recent version of an ad. Such an approach eases the ad updating process. The advertiser 36 may also select the date and/or times that a particular ad should run. Thus, one type of ad may be used for a particular product before evening time, and another type used during and after evening hours. [0022] [0022]FIG. 2 depicts the advertising selection and retrieval computer system as generally shown at 40 . The advertising selection and retrieval computer system of the present invention ensures delivery of the ad to the customer. It should be understood that the advertising management server and advertising selection and retrieval server are preferably implemented as separate computer servers, but may be implemented on the same server depending upon the application at hand. [0023] The present invention retrieves audio ads from the advertising database 38 in response to an incoming call from a customer 42 . The customer may be using a telephone or a wireless communication device to have a service performed for the customer 42 . An example of a service includes the telephony server 44 receiving a call from the customer 42 so that the customer 42 may locate a restaurant in a certain city. The telephony server 44 uses the web content server 46 to access a restaurant-locating software application that is on a network, such as the Internet 50 . The application may be a VoiceXML application located on a remote web site 52 . Another exemplary application includes a customer 42 calling to locate the phone number of another individual. In this latter example, the application is a phone number lookup VoiceXML application. [0024] The telephony server 44 forwards the incoming call to a web content server 46 . The web content server 46 formulates a hypertext transfer protocol (http) request for an audio ad. The request is sent to the advertising selection/retrieval server 48 for processing. The advertising selection/retrieval server 48 selects an appropriate audio ad from the advertising database 38 and sends back an ad location identifier to the web content server 46 . The web content server 46 retrieves the audio file from a web site 54 based upon the ad location identifier and dynamically inserts the ad audio file into the VoiceXML application. The web content server 46 performs the functions of the VoiceXML application and then plays the audio file through the telephony server 44 for the customer. [0025] The web content server 46 may include in the http request such information as the type of customer that is placing the incoming call. The web content server 46 knows what type of customer is placing the incoming call based upon information that the customer has already provided to the telephony server 44 . For example, the telephony server 44 may know where the customer is located based upon the area code of the incoming call or the telephony server 44 has a database that stores profiles of its customers. The customer's request may also furnish additional information. For example, if the customer is requesting jewelry information, then the web content server 46 may supplement the http request with that profile information. In such a situation, the advertising selection/retrieval server 48 may heighten the probability that a jewelry-related audio ad be selected. The telephony server 44 may also have asked the customer questions about the customer's profile. [0026] The advertising selection/retrieval server 48 selects an audio ad based upon certain predetermined rules. The ad selection rules include: balanced ad usage rules, profit rules (e.g., revenue sharing rules), target customer profile rules, and other selection rules that will be apparent to one skilled in the art. The balanced ad usage rules ensure that audio ads are played at least a certain amount of times. The profit rules optimize the amount of earnings the operators of the present invention acquire for the playing of the audio ads. For example, the profit rules may indicate that a first audio ad be played more often than a second audio ad when the first audio ad's financial arrangement is based upon a profit-sharing arrangement, and the second audio ad's financial arrangement is a set fee arrangement. The target customer profile rules ensure that audio ads that fit a customer profile are played. For example, a jewelry-related audio ad is played for a customer who has requested jewelry-related information. Examples of other selection rules include accounting information (such as whether the advertiser is current in its payments to the operators), application service provider configuration, and content provider configuration. [0027] The telephony server 44 provides ad usage data which is stored in the advertising database. The telephony server 44 records how long an audio ad was played to a customer 42 . A customer 42 may terminate the call before the entire audio ad was played. The ad usage information is sent to advertisers to provide feedback on the quality of their ads. For example, if a certain ad is habitually terminated early by customers, then this serves as an indication that the ad may need to be improved or replaced. [0028] The present invention operates with free content providers. In this context, the system of the present invention is entitled to a certain number of minutes (i.e., four minutes) of its own ad for every time slot (e.g., twenty-two minutes) while the application service provider provides a piece of time for its own ad. In other words, for every block of time, say thirty minutes, the content provider can use only twenty-two minutes of that time block while keeping the remaining four minutes for its own ad and four minutes for the application service provider. [0029] [0029]FIG. 3 is a block diagram that depicts the revenue sharing system of the present invention. The hosting company 60 , who owns the advertising servers charges a one time listing fee and monthly platform usage fees from advertising agencies 36 and telephony server operators 62 . The advertising agencies 36 pay the hosting company 60 with the listing fee and monthly platform fee, and pay the telephony server operators 62 the ad usage fee. [0030] The telephony server operators 62 pay the hosting company 60 the listing and monthly platform fees and receive the ad usage fees from matched advertisers. The telephony server operators 62 distribute the ad fees with the connected application providers 64 , and charge the application providers 64 the application usage/listing fees. [0031] [0031]FIG. 4 is a flowchart depicting steps to process an advertising request from an advertiser. The start indication block 70 indicates that process block 72 is to be performed. At process block 72 , an advertiser provides a bid 74 so that its ad may be played. The advertiser's bid 74 may contain the payment arrangement, the times and dates the ad should be played, and the customer profile. [0032] At process block 76 , the system of the present invention queries the advertising database to determine which telephony servers (if any) are willing to accept the advertiser's bid 74 . As discussed above, the system may accept the bid 74 if the bid 74 contains a payment amount that at least one of the telephony servers finds satisfactory. A telephony server may be more willing to accept a lesser amount to play an ad if the advertiser allows the ad to be played during non-premium times. An example of a non-premium time includes the time between midnight and 6:00 a.m. The telephony servers may also adjust their asking prices based upon the service or VoiceXML application to be provided to the customer. A more sophisticated VoiceXML application may warrant a higher asking price. [0033] A telephony server may also provide a range of acceptable prices to advertisers. The telephony server may remain fixed at a certain higher price for two bidding iterations with an advertiser, then negotiate downward to its lower range price for subsequent iterations. [0034] If the system accepts the bid as determined by decision block 78 , then process block 80 places the ad (or its location identifier) and its accompanying data (e.g., customer profile data) within the advertising database. Processing terminates at end block 82 . [0035] However, if the system does not accept the bid as determined by decision block 78 , then process block 84 notifies the advertiser that the bid is not accepted and the basis for non-acceptance. Such a basis may include the payment amount as specified in the bid 74 being insufficient or that the times and dates are not available for playing the ad. The system may further supplement its notification of non-acceptance by providing (if available) statistics at process block 86 to the advertiser. An example of the type of statistics provided to the advertiser includes what the average payment amount is for an ad similar to the ad that the advertiser wishes to play. Another example includes statistics on how well other ads placed by the advertiser had fared. If other ads by the advertiser have a low ad usage rate due to customers habitually terminating the audio playing of the ad, then the system may expect a higher payment for playing this new ad of the advertiser. Still other statistics are included within the scope of the present invention as are apparent to one skilled in the art. The bid/ask process is iterated until the bid is accepted by the system or the advertiser does not provide a further bid. [0036] [0036]FIGS. 5 and 6 are flowcharts that depict steps to process an incoming call in accordance with the teachings of the present invention. Start indication block 90 indicates that process block 92 is performed. At process block 92 , a user/customer places a call in order to request a service. A telephony server receives the incoming call at process block 94 . [0037] At process block 96 , the telephony server determines the profile of the customer, and process block 98 provides the customer profile to the system via the web content server. Process block 100 includes the system formulating the search criteria based upon the information provided by the telephony server and the preselected rules. The system retrieves at process block 102 the proper ad based upon the search criteria and provides the web content server with the ad at process block 104 . Continuation block 106 indicates that processing continues at process block 108 on FIG. 6. [0038] With reference to FIG. 6, process block 108 retrieves via the web content server the proper VoiceXML application in order to service the request of the customer. At process block 110 , the web content server inserts the ad into the VoiceXML application. The telephony server at process block 112 performs the service as dictated by the VoiceXML application. [0039] The ad is played to the customer at process block 114 . At process block 118 , the telephony server determines how long the ad was played to the customer, and that information is provided to the system of the present invention at process block 118 . Processing terminates at end block 120 . [0040] The preferred embodiment described with reference to the drawing figures is presented only to demonstrate an example of the invention. Additional and/or alternative embodiments of the invention will be apparent to one of ordinary skill in the art upon reading this disclosure. For example, the above discussion mentioned VoiceXML applications as providing services requested by customers. It should be understood that the present invention includes using any software application (including other voice markup language applications) that can be used to supply services to customers whether the customers are on a wireless communication device (such as a hand-held cellular communication device) or on their computers.

A computer-implemented audio advertising system for providing audio advertisements to users over a network. An advertising management server receives audio advertisements and advertisement account data over the network. An advertising database stores the audio advertisements and advertisement account data. Upon requests from telephony services, an advertising selection and retrieval server fetches audio ads according to a set of effective searching criteria. The retrieved audio ad is played to users of the telephony services.

BACKGROUND OF THE INVENTION The present invention relates to an apparatus and method for use in respirator masks and/or rebreather hoods for absorbing noxious gases and providing an adjustable oxygen output and carbon dioxide consumption from an "at rest" level up to a high stress level, such as that which occurs during heavy work conditions. Many devices, including respirators and rebreathers, are well known in the art whose function is to provide oxygen and absorb carbon dioxide for various uses, including health care applications, and to protect a user from airborne gaseous contaminants from fires, etc. Such devices employ various strong chemical and physical absorbants in order to remove contaminants from gaseous or liquid streams. Chemically reactive compounds such as soda lime (ascarite) and anhydrous lithium hydroxide are carbon dioxide absorbers which are widely used. Chemical oxygen sources such as chlorates, peroxides, and alkali metal superoxides are also well known. Physical absorbents include for example, activated carbons, zeolites, silicas, aluminas and ion exchange resins. Most devices are limited by the rate at which they provide oxygen and the conditions under which they can be used. In addition, these devices are not designed to protect the user against all types of airborne contaminants which the user may encounter. For instance, recent publications show that there are long-lived free radicals which are present in the smoke from burning organic materials. These free radicals can react with lung surfaces if they are inspired and thereby cause severe damage and even death. Respirators commonly use cartridge-type filters containing selective absorbents for noxious gases and inspired air. These devices are designed to remove undesired chemicals and particulate matter from incoming air, enhance the oxygen level within the mask, and eliminate carbon dioxide, either directly or in conjunction with mechanical check valves. Respirators are useful only when ambient oxygen levels are at least 19.5%. For oxygen levels below this level, separate mechanical supplies of air or oxygen are used, such as tanks of compressed gases, or remote source air pumping. These devices are bulky and complicated, and the user must be trained in their proper use. Rebreathers are a separate class of emergency use respirators, usually in hood form, which are designed to continuously absorb or remove respired carbon dioxide, and excess moisture. Rebreathers obtain their air supply from that which is trapped when the user puts on the hood. Anhydrous lithium hydroxide is often used to absorb the respired carbon dioxide. However, rebreathers have limited service life because oxygen levels are not replenished. Compressed air devices are prone to mechanical problems with release valves and the user is required to operate them properly under life-threatening conditions. Rebreathers using moisture activated alkali metal and alkaline earth metal superoxides and the like as both an oxygen source and a carbon dioxide absorber have been tested extensively. Basically, these chemicals react readily with moisture in respired air and evolve oxygen, while at the same time providing a reaction product which will absorb carbon dioxide. Potassium superoxide is especially useful for this purpose and has been employed in many respiratory devices. However, several problems have prevented their full commercial development. One problem is a delay or start-up period which occurs before oxygen delivery begins. Also, the practical size and operating conditions of these devices place limitations on the quantities of functional chemicals and the design geometry in which they are used. Additionally, oxygen output efficiency declines significantly as the breathing rate increases. Therefore, at high stress levels, the moisture content of the respired air is inadequate to generate the necessary oxygen levels. The above problems have been addressed in several manners. For instance, a separate injectable water source has been tested, but not successfully. In addition, compacted briquettes of the superoxide are able to provide extended oxygen delivery times, and the use of large quantities of the same are able to over-ride the efficiency loss. However, the resulting exothermic heat of reaction with water is sufficient to require external heat exchangers on the superoxide cannisters. Under these conditions, the rebreather must be physically separated from the chemical source for obvious safety reasons. In addition to the above devices, synthetic and natural zeolites of certain composition and porous sizes are used in pressure swing absorption devices to produce commerically high purity oxygen from air. Zeolites are a family of crystalline hydrated alumino-silicate minerals, with the general formula MN 2 O-Al 2 O-nSiO 2 -mH 2 O where M is calcium, strontium or barium and N is either sodium or potassium. The ability of zeolites to function as molecular sieves, separating complex gas mixtures into various components is derived primarily from the highly uniform porous structure of the zeolite crystal which is a 3-dimensional network of interconnecting cavities. Large polar molecules are retained on the zeolite by Van der Waals forces rather than chemical bonding, while smaller and less polar molecules are not. Air pressure well above atmospheric is required for the efficient operation of the zeolite system. In addition, since zeolites are both powerful dessicants and selective gas absorbants, the air must be pre-dried, or large excesses of zeolite must be used in order to compensate for the moisture in ambient air. In its practical use as an oxygen concentrator, the air is compressed and passed through a column of zeolite material. The more polar components of air, i.e., water vapor, carbon dioxide, and such pollutants as carbon monoxide, sulfur dioxide, nitrogen oxides, and hydrocarbons are immediately absorbed on to the uppermost layer of the zeolite, the nitrogen fraction is selectively removed, leaving oxygen, traces of inert gases and some residual nitrogen. The zeolites are the active agents in many continuous generators of oxygen-enriched air for health care applications, for example for use with patients having severe chronic obstructive pulmonary disease (COPD). In accordance with the above, it is an object of the present invention to provide an apparatus and method for selectively absorbing undesirable organic and inorganic gases and vapors from ambient air while providing oxygen level enchancement of the treated air which is more efficient than prior are methods and devices. It is another object of the present invention to provide unique modifications of the chemical materials commonly used in such systems to provide extended and controlled oxygen production and utilization efficiencies that allow for major reductions in the sizes and weights of the components. It is a further object of the present invention to provide unique designs of component configurations and arrays in order to make them compatible with established breathing mask structures of both respirator and rebreather types and which can also be used in ventilating applications. It is another object of the present invention to provide an apparatus and method which allows the activation of an oxygen generating system on demand. It is yet another object of the present invention to provide an oxygen enrichment system which is simple and inexpensive to manufacture, safe and easily disposed after use. It has now been surprisingly discovered that by combining the use of the above-mentioned compounds in a unique manner, the efficiency gain is much greater and different from an additive effect of each of the components. SUMMARY OF THE INVENTION Thus, in accordance with the above-mentioned objectives, one aspect of the present invention relates to a multi-chamber permselective apparatus for providing oxygen-enriched filtered air matched to a range of breathing rates, comprising a first chamber containing microcapsules comprising an oxygen generating compound as a core material and a coating which is moisture swellable but not soluble, wherein the coating slowly exposes the core material to moisture when exposed to respired air, thereby allowing the core material to react with the moisture and generate oxygen; a second chamber containing a solid carbon dioxide absorber for absorbing carbon dioxide from respired air; a third chamber containing an aqueous solution of mildly acidic salt with a small amount of nonionic surfactant; and a fourth chamber containing aqueous hydrogen peroxide and a small amount of nonionic surfactant. The chambers are made from a semi-permeable fabric, which prevents fluid penetration under normal pressure but allows fluid to pass through under moderate over-pressure. The invention also comprises a first pressure means for forcing the aqueous solution from the third chamber into said first chamber during faster breathing rates, and a second pressure means for forcing the aqueous solution from the fourth chamber into the first chamber during prolonged faster breathing. In preferred embodiments, the multi-chamber permselective apparatus further comprises a fifth chamber also made from semipermeable fabric which contains an immobolized sorptive particulate material for selective absorption of noxious and other undesired gases which is cationically exchanged with a heavy metal ion. In other preferred embodiments, the semi-permeable fabric is coated with an antioxidant. Alternatively, a sixth chamber may be included which includes an antioxidant. Preferentially, the antioxidant comprises 2,6-tert-butyl-p-cresol, propyl gallate, t-butylhydroxy quinone, a butylated hydroxyanisole or a mixture thereof. This device is contemplated for use in respirator masks and/or hoods of the rebreather type. Each chamber of the device carries a different chemical and has a specific function. Overall, the device absorbs noxious gases and provides an adjustable oxygen output and carbon dioxide consumption matched to the oxygen demand of the user. Although the major function of the unit is to provide oxygen generation and carbon dioxide absorption matched to a range of breathing rates, it is also directed to selective gas absorption and free radical termination as secondary functions. The device is designed to provide user protection against airborne gaseous contaminents from fires in buildings, factories, aircrafts, mines, etc. The present invention is also related to a filter for generating oxygen and absorbing noxious and other undesired gases comprising a plurality of layers including an immobilized sorptive particulate material which is cationically exchanged with a heavy metal ion, and at least one layer comprising an oxygen generating compound, said oxygen generating layer being in juxtaposition with said layers of immobilized sorptive material layers. The present invention is also related to a method for generating oxygen gas comprising adding a strongly basic compound and an oxygen generating material which is substantially completely free of heavy metal salts to a solution comprising aqueous hydrogen peroxide substantially completely free of heavy metal salts and thereafter contacting the solution with a composition containing a heavy metal in elemental form to generate oxygen gas. The oxygen generating material dissolves in the solution, thereby raising the pH, and the aqueous hydrogen peroxide decomposes to water and oxygen upon contacting the heavy metal. This double decomposition procedure has advantages over prior art methods of generating oxygen through the use of either component alone because of an unexpectedly higher oxygen delivery capacity than an additive effect would dictate. In preferred embodiments, the oxygen generating compound comprises potassium superoxide, lithium superoxide, magnesium peroxide, calcium peroxide, sodium peroxide calcium peroxide, lithium superoxide, potassium peroxide, or a mixture thereof and the immobilized sorptive particulate material comprises a copper or iron exchanged clinoptilolite or mordenite. The novel devices and unique modifications of the chemical materials used herein provide extended and controlled oxygen production and utilization efficiencies which allow for major reductions in the sizes and weights of the components. Other advantages occur in manufacture, safety and disposal. In addition, the present invention may be used in ventilating applications or alternatively in breathing masks of both the respirator and rebreather type. BRIEF DESCRIPTION OF THE DRAWINGS The following drawings in which like reference characters indicate like parts are illustrative of embodiments of the invention are not meant to limit the scope of the invention as encompassed by the Claims. FIG. 1 is a cross-sectional view of a cartridge type apparatus of the present invention; FIG. 2 is a perspective view showing the cartridge type apparatus of FIG. 1 a rebreather mask; FIG. 3 is a cross-sectional view of a free standing absorber apparatus of the present invention; FIG. 4 is a perspective view showing the free standing apparatus of FIG. 3 within a rebreather unit; FIG. 5 is a schematic view of a test apparatus comprising a closed loop system for the present invention; FIG. 6 is a graphical representation of the oxygen generation of microencapsulated potassium superoxide; FIG. 7 is a graphical representation of a comparison of oxygen generation by lithium hydroxide alone against lithium hydroxide together with potassium superoxide microcapsules; FIG. 8 is a graphical representation of a comparison of the effect of the presence of fumed colloidal silica on oxygen transport in a molecular sieve. FIG. 9 is a graphical representation of a comparison of oxygen generation by a 5A mole seive coated with hydrophobic colloidal silica against iron mordenite. DETAILED DESCRIPTION The present invention provides O 2 generation and CO 2 absorption matched to a range of breathing rates and also provides selective gas absorption and free radical termination. This is accomplished by providing different chemical components, having specific functions. The chemical components include: a solid oxygen generating compound reactable with water to form oxygen and which is microencapsulated in a wall material that is moisture swellable but not soluble; a solid CO 2 absorber; a cation exchanged zeolite; an aqueous solution of a mildly acidic salt with a small amount of nonionic surfactant; aqueous hydrogen peroxide preferentially of approximately 30 percent strength with a small amount of nonionic surfactant; and one or more antioxidants considered GRAS. In brief, oxygen is derived from both the oxygen generating compound and the hydrogen peroxide. Carbon dioxide is absorbed by both LiOH and the reaction product of the oxygen generating compound and water. The zeolite is a selective absorbent for carbon monoxide and can also absorb other noxious gases such as SO 2 and NOX. In addition, as will be discussed in detail below, the combination of the microencapsulated oxygen generating compound, such as potassium superoxide, and zeolites cationically exchanged with heavy metal ions provide surprisingly high levels of oxygen. The antioxidants are scavengers for free radicals present, for example, in the smoke from fires. Aqueous MgCl 2 can be used as a source of additional water to increase oxygen release from the oxygen generating microcapsules and/or to decompose the alkaline reaction products from the same. The specific actions and reactions of these chemicals will be discussed below. The multi-chambered unit to which the present invention is directed is made of a semi-permeable fabric. Each chamber carries a different chemical and each has a specific function. The term semi-permeable fabric is defined herein as a broad group of woven and non-woven materials whose physical structure is controlled to give breathability; that is, to allow passage of air but not liquids. Needle punching, leaching of dispersed soluble salts, fibrillation, and biaxial orientation are some of the well known methods for producing controlled porosity. There are many water repellent finishes for conventional porous fabrics that will render them semi-permeable. These finishes will prevent water penetration under normal pressure, but water can be forced through under moderate over-pressure. In this fashion the fabric can function as a pressure activated valve to admit liquids on demand. One material of choice is a widely used fabric called Goretex available from W. L. Gore Co., which is an oriented, microporous teflon composite. Other acceptable semi-permable fabrics include CT breathable film, available from Consolidated Thermoplastics Co. (an oriented, microporous polyurethane), and water resistant nylons and canvases available from various suppliers. The chambers will vary is size and volume depending on the required level and duration of performance. The largest chamber will be the peroxide holder, and it will contain one or more microencapsulated solid oxygen generating chemicals. Various geometric shapes and designs are possible. Two of these possible designs have been selected for purposes of example. The first is a disc shape similar to the filter cartridge units commercially sold for respirator masks. It would be used in a face mask in which air is reversibly forced through the filter by breath action (Dynamic air flow). The second type is a free standing absorber pad for a hood type rebreather in which breathing causes air circulation. Device activation occurs by permeation and diffusion (passive or semi-static air flow). Referring to FIG. 1, the cartridge type model 10 consists of 3 chambers arranged in sandwich fashion and made of Goretex fabric. The layers may be separate or mutually attached and housed for convenience and handling in a rigid, open-grid container made of polypropylene, high impact polystyrene, or other impact resistant thermoplastic. Attached to the circumference of the outside edge of the microcapsule chamber 1 are either one or two elastomeric chambers for reactive liquids. In the embodiment herein depicted, chamber 2 contains a reservoir of aqueous hydrogen peroxide, while chamber 3 contains a reservoir of a mildly acidic salt such as aqueous MgCl 2 solution, each with a small amount of nonionic surfactant. The liquid contents are kept separate from the microcapsules by means of frangible discs 6, 7 made of brittle, impermeable plastic such as polystyrene. Mounted onto and through the elastomeric walls are plungers 4, 5 which extends as studs or buttons outside the chamber and terminates in a sharp point inside the chamber and in proximity to the frangible discs 6, 7. The elastomeric material comprising the elastomeric walls may be any oxidation resistant rubber or elastomeric thermoplastic. A preferred material is neoprene. Depressing either plunger 4, 5 ruptures the respective frangible disc 6, 7 and allows the contained liquids to contact the outer wall of the microcapsule chamber 1. Repeated depressions of the plunger 4, 5 pumps the liquid through the wall by the overpressure technique previously described. Alternatively, the frangible discs 6, 7 can be backed by and a porous conduit 8. Porous conduit 8 is made of a porous material. In the present example, a porous plastic is molded into the walls of the microcapsule chamber 1 and extends transversely through the diameter of microcapsule chamber 1. In this embodiment, frangible discs 6, 7 are preferentially located at either end of porous conduit 8. FIG. 2 is a perspective view showing the cartridge module in place in a rebreather mask. FIG. 3 shows a free standing absorber module 20 for passive flow use for a hood type rebreather in which activation occurs by permeation and diffusion. The outer structure comprises a module holder which holds the multi-chambered unit. The module 20 comprises the microcapsule chamber 24 which contains one or more micro-encapsulated solid oxygen generating chemicals 26. Attached to the microcapsule chamber 24 at either end are either one or two chambers for reactive liquids. In the module herein depicted, reactive chambers 28 and 30 are arranged at either end and contain aqueous hydrogen peroxide and aqueous MgCl 2 respectively, each with a small amount of nonionic surfactant. Mounted onto and through module holder 22 are plungers 31, 32 which terminate in a sharp point inside chambers 28 and 30, respectively, and in proximity to frangible discs 33, 34. frangible discs 33, 34 are located at either end of porous conduit 36. Alongside microcapsule chamber 1 are two additional chambers. Chamber 38 contains a solid carbon dioxide absorber such as solid anhydrous LiOH particles 40, although any of the well known solid carbon dioxide absorbers may be substituted in its place. Chamber 42 contains a copper or iron exchanged clinoptilolite or mordenite. FIG. 4 is a perspective view showing the free standing absorber module placed within a rebreather hood, for passive or static use with an alternate module. Additionally, in preferred embodiments the present invention also includes antioxidants as scavengers for the free radicals either as a separate layer in the unit, or preferably as a coating on the semi-permeable fabric of the unit. The antioxidants are non-volatile under these use conditions and are not transferred to the air stream. Food grade antioxidants are used for safety. These antioxidants are used for safety. These antioxidants are commonly referred to in the art as GRAS antioxidants, and include 2,6-di-tertbutyl-p-cresol, propyl gallate, t-butyl hydroxy quinone, butylated hydroxyanisole, combinations of any of the foregoing, and the like. The above devices have been designed in component configurations and arranged in order to make them compatible with established breathing mask structures. However, these configurations may be changed in manners apparent to those skilled in the art in order to make them compatible with new structures which may arise. Although mechanisms have been provided herein for activating the system on demand, the chemicals and the multi-chambered unit as a whole function differently depending upon the breathing rate and the work level of the user. However, for the purposes of this disclosure, their function can be categorized into three breathing rate levels; namely, (1) slow or at rest, (2) fast breathing, and (3) high stress rate breathing. At condition, (1) typical oxygen demand is about 0.3 liter/min and CO 2 generation is 0.25 liter/min. As breathing and work rate increases, oxygen need greatly increases and CO 2 production rate increases faster than that of O 2 demand. At high stress rates, CO 2 /O 2 , are in balance, with both at a level of 2.5 liters/min or about 8.3 times the at-rest requirements. The oxygen generating compound such as potassium superoxide and the like is a demand source of chemical oxygen. When this compound reacts with water, it forms potassium hydroxide which absorbs carbon dioxide. In the present invention, it is used in a microcapsule form having a very small particle size (approximately 250-1000 microns), since the bulk form of this compound is not adaptable to compact cartridge design. In bulk form, the compaction density of the potassium superoxide is relied upon to control permeation and diffusion of moist air and give extended release times. The small particle size provides a very reactive and large surface area when the capsules open. As these microcapsules are exposed to moisture, the coating slowly peels back in an exfoliating manner, exposing increasing amounts of the core material. Thus, unlike the bulk form, the active core material is available only in proportion to the number of capsules "opened" by incoming moisture. The microencapsulated oxygen generating material generally comprises a core material comprising an oxygen generating compound and a coating comprising an acceptable wall-forming water swellable polymer, and are disclosed in U.S. Pat. No. 4,867,902, filed on, 1988, the assignee of record, and incorporated herein by reference in the interest of brevity. Preferably, the core material comprises one or more of the alkali and alkaline earth peroxides, superoxides, trioxides, percarbonates or permanganates. Most preferably, the core material is comprised of potassium superoxide. The water swellable coating preferentially comprises a copolymer of an olefin such as ethylene, propylene, isobutylene, or styrene and a vinyl compound such as vinyl acetate, vinyl alcohol, the alkyl, hydroxyalkyl and amino alkyl acrylic and methacrylic esters, maleic anhydride, maleate esters, maleate salts, vinyl alkyl ethers, vinyl pryidive, vinyl pyrollidone, and vinyl sulfonic acid, esters and salts; homopolymers of the above-mentioned vinyl monomers, acrylics and maleic anhydrides; anhydrous polymeric alkylene oxide polyols and alkoxy derivatives having a molecular weight greater than 500; gelatins; starches; gums; polyamides; polyurethanes modified for high hydroplilicity; and mixtures of any of the foregoing. The microcapsule coating may also comprise one of the combustion resistent coatings disclosed in previously mentioned U.S. Pat. No. 4,867,902. At slow breathing rates, respired moisture causes the microcapsule coating to swell and peel back in the previously mentioned exfoliating manner, thus allowing water to react with the oxygen generating compound. Although the reaction between the oxygen generating compound and water differs slightly depending upon whether the oxygen generating compound is in the peroxide, superoxide, trioxide, etc., form, the end result is substantially the same in that oxygen is generated and the resultant alkali or alkaline earth hydroxide thus formed absorbs carbon dioxide. The various reactions are set forth in Table 1. TABLE 1______________________________________Reactions of the Oxygen Generating Compounds______________________________________Compounds: Peroxides - M.sub.2 O.sub.2 Superoxides - MO.sub.2 Trioxides - M.sub.2 O.sub.3Reaction with H.sub.2 O (O.sub.2 evolution) 2M.sub.2 O.sub.2 + 2H.sub.2 O → 4MOH + O.sub.2 2MO.sub.2 + H.sub.2 O → 2MOH + 3/2O.sub.2 M.sub.2 O.sub.3 + H.sub.2 O → 2MOH + O.sub.2Reaction of CO.sub.2 with Hydroxide (MOH) MOH + CO.sub.2 → MHCO.sub.3 2MOH + CO.sub.2 → M.sub.2 CO.sub.3______________________________________ Since the oxygen generating particles emerge on a gradual or timed basis, there initially are not enough available particles to absorb all of the carbon dioxide present. Accordingly, an additional chamber containing solid anhydrous lithium hydroxide is provided as a supplementary carbon dioxide absorber. As the breathing rate increases (thereby increasing the moisture present), the microcapsules open more rapidly, and the lithium hydroxide serves a secondary role. For fast breathing rates, hereafter referred to as a first breathing rate, it is necessary to provide more moisture to the microcapsules than the amount obtained from respiration. In this case, an aqueous solution of MgCl 2 , with a small amount of surfactant is pumped into the microcapsule chamber from an attached reservoir. Oxygen evolution and gas flow become very rapid and diffusion of carbon dioxide to the oxygen generating sites is inhibited. Lithium hydroxide is the primary carbon dioxide absorber. The contained surfactant aids in wetting the organic capsule surfaces. The MgCl 2 serves two functions; namely, as an anti-freeze and as a decomposition agent for the alkaline salts from the oxygen generating compound/water/carbon dioxide reaction An insoluble gel of magnesium hydroxide/carbonate is formed together with pH neutral salt, such as potassium chloride when potassium oxides are used. Instead of MgCl 2 , other well known salts in the art which provide signficant freezing point depressions in aqueous solutions and which form substantially insoluble compounds when reacted with alkali hydroxides and/or carbonates may be used. Examples include CaCl 2 , FeCl 3 and ZnCl 2 . For high stress breathing rates, hereafter referred to as a second breathing rate, the oxygen requirements are supplied by both the microencapsulated oxygen generating compound and hydrogen peroxide. In this situation, aqueous hydrogen peroxide (30 percent strength, for example) containing surfactant is pumped from its reservoir to the microcapsule chamber. A double decomposition reaction occurs which comprises the reaction of the oxygen generating compound (i.e., potassium superoxide) with aqueous hydrogen peroxide, and subsequent metal catalyzed decomposition of the resulting metastable alkaline aqueous hydrogen peroxide. For purpose of the present disclosure, metastable means chemically unstable, but not liable to spontaneous rapid decomposition. The double decomposition procedure has the advantage of higher oxygen delivery capacity than either system alone. The individual chemical reactions are as follows: KO.sub.2 +2H.sub.2 O→2KOH+O.sub.2 2aq.H.sub.2 O.sub.2 →2H.sub.2 O+O.sub.2 Overall, the simplified reaction is: ##STR1## Specifically, the double decomposition reaction comprises the in situ formation of potassium hydroxide substantially free of heavy metal salts which dissolves in the aqueous hydrogen peroxide as the oxygen is being liberated, thereby raising the pH of the aqueous hydrogen peroxide from its normal range of pH 3-5 to its metastable range of pH 9-12. Gradual decomposition of the metastable hydrogen peroxide to oxygen and water then occurs, thus providing a secondary source of oxygen. The decomposition to water and oxygen has been found to be controllable by contacting the solution with solid metal surfaces. As previously mentioned, the alkaline aqueous hydrogen peroxide is metastable. It is known in the art that metastable aqueous hydrogen peroxide decomposes rapidly and uncontrollably in the presence of soluble heavy metal salts. However, only chemically pure alkalis can be used to make metastable aqueous hydrogen peroxide, since metal salt impurities are sufficient to cause decomposition. Microfine silver and samarium catalysts are used to promote the violent and instantaneous decomposition of concentrated hydrogen peroxide into oxygen and steam. It has use for propulsion of rocket sleds and related devices, but is not suited for controlled release systems. It has been found that solid forms (rods, wires, screens) made of any of stainless steel, copper, iron, carbon steel, silver, nickel, or chromium initiate oxygen release from metastable aqueous hydrogen peroxide. Removal of metal source stops the oxygen release, and it can be re-started repeatedly by replacing the metal catalyst. Once again, the gas flow rates which occur during this prolonged high stress rate operation are such that the lithium hydroxide becomes the primary carbon dioxide absorber. Optionally, the MgCl 2 solution can be used to neutralize the alkaline reaction products when the oxygen release is completed and the unit is to be disposed of. In addition to the advantages provided by the multi-chambered unit in regard to the increased oxygen release provided by the double decomposition reaction discussed above, the present invention has a further novel feature in that it has been found that the selective absorption of noxious and/or undesired gases and the extended controlled production and delivery of oxygen through the utilization of both physical means, i.e. zeolites cationically exchanged with heavy metal ions, and chemical means, i.e. superoxide/water reaction, in the unique compact form herein disclosed provides an efficiency gain which is much greater and different from an additive effect of these components. This result occurs with or without added anhydrous lithium hydroxide. This result is totally unexpected given the fact that superoxides function only by reacting with water, while zeolites absorption capacity is deactivated by water. In addition, superoxides work well at atmospheric pressure whereas zeolites do not. One possible explanation for this phenomenon is that there is a complex interaction of absorption dynamics with small particle size and high specific absorbency chemicals. It may also include effects due to reduced competition for absorbency chemicals. It may also include effects due to reduced competition for absorption sites and gas transfer process. More particularly, one possible explanation for this phenomenon could be a combination of the following: the increased surface area of the small oxygen generating particles can compensate for short gas/solid contact times required for efficient permeation and diffusion, thus effectively achieving a longer pathway; the hydrophobic zeolites function as selective gas absorbents rather than as dessicants; the lithium hydroxide in the unit functions exclusively as a carbon dioxide absorber and thereby decreases competition for carbon dioxide absorption sites in the zeolites; oxygen generation and carbon dioxide and the like is enhanced by the microencapsulated form (shorter diffusion pathways); and continuous generation of oxygen from the microcapsules in juxtaposition to hydrophobic zeolite surfaces causes a gas transfer phenomenon in which absorbed gases, i.e., nitrogen and carbon dioxide, are constantly displaced from the zeolites by oxygen, and then more effectively reabsorbed upon cycling through filter. DESCRIPTION OF THE PREFERRED EMBODIMENTS The following examples illustrate various aspects of the invention. They are not to be construed to limit the claims in any manner whatsoever. EXAMPLES 1-6 Microcapsules comprising various oxygen generating core materials and a wall-forming water swellable coating were prepared in accordance to methods well known in the art (particle size 250-1000 microns), and their oxygen generating properties were tested. The results are shown in Table 2. TABLE 2______________________________________Properties of KO.sub.2 and Alternate Inorganic OxidesCoreCompound % contained lbs O.sub.2 /lb lbs CO.sub.2 /lb*(formula) (MW) oxygen (generation) (absorption)______________________________________KO.sub.2 71 45 0.34 0.31K.sub.2 O.sub.3 126 38 0.25 0.35Li.sub.2 O.sub.2 46 69.5 0.35 0.96Na.sub.2 O.sub.2 78 41 0.21 0.56NaO.sub.2 55 58 0.43 0.40Ca(O.sub.2).sub.2 104 61.5 0.46 0.42______________________________________ *calculated as carbonate EXAMPLES 7-10 The properties of MgCl 2 and alternate salts used in the present invention as a source of additional water to increase oxygen release from the microcapsules and/or to decompose the alkaline reaction products from the same were tested at different weight percentage. The results are shown in Table 3. TABLE 3______________________________________Properties of Mg Cl.sub.2 and Alternate SaltsAq. solution(Percentage byweight of dissolved Freezing Point Depression (°C.)salt) CaCl.sub.2 MgCl.sub.2 FeCl.sub.3 ZnCl.sub.2______________________________________1 0.44 0.55 0.38 0.453 1.33 1.62 1.13 1.255 2.36 2.97 1.90 2.19 7.5 3.93 5.14 3.16 3.7810 5.85 7.91 4.77 5.5215 11.0 15.64 9.33 9.83Solubility inwater 20° C.(g/100 g H.sub.2 O)Hydroxide 0.10 0.009 0.001 0.001Carbonate 0.0014 0.0106 0.001 0.001______________________________________ EXAMPLE 11 A cartridge type module similar to that shown in FIG. 1 having chambers containing potassium superoxide microcapsules, anhydrous lithium hydroxide, cationic zeolite, a reservoir of aqueous of 30% strength hydrogen peroxide, and a reservoir of aqueous MgCl 2 was tested in order to determine its oxygen delivery capacity and its useful working life. The dimensions of the individual chambers and their contents are provided in Table 4. TABLE 4______________________________________DISK TYPE MODULE CHAMBER DIMENSIONS Volume Contained Diameter Height (CC) Wt. (GMS) (In.) (In.)______________________________________KO.sub.2 Microcapsules 163 86.2 4 0.8Anhydrous Lithium 82 36 4 0.4HydroxideCationic Zeolite 15 10 4 0.0830% H.sub.2 O.sub.2 30 30 (a) (a)10% aq MgCl.sub.2 30 -- (a) (a)______________________________________ (a)Attached to the circumferential edge of the KO.sub.2 microcapsules chamber. Length 3" of circumference, width 0.8", Height 0.75". Upon activation, the oxygen delivery capacity was determined to be approximately 24 liters at 25° C. The useful working life depended upon the breathing rate of the user. At low stress (rest) breathing rates, the useful working life of the module was greater than 80 minutes. At high stress breathing rates, the useful working life was determined to be approximately 9-10 minutes. EXAMPLES 12-14 Examples 12-14 are directed to the effect of the inclusion of solid metals in the double decomposition reaction and the effect of different forms of potassium superoxide. In Example 12, powdered potassium superoxide was added to FMC 35% superD hydrogen peroxide (pH 3-5) and oxygen production was essentially immediate. The resulting alkaline mestable aqueous hydrogen peroxide (pH 9-12) showed no evidence of spontaneous oxygen release. Loops of 0.0625" diameter copper wire immersed in the liquid caused slow, steady gas evolution from the immediate wire surface. The test was repeated successfully with wires made from each of silver, iron, carbon steel, stainless steel, nickel, and chromium. The same metal wires placed in regular 35% hydrogen peroxide did not cause oxygen release. In Example 13, microencapsulated potassium superoxide was used instead of potassium superoxide powder in a repeat of the tests from Example 1. The major difference observed was that oxygen release from potassium superoxide occured over an extended time period and the pH increase also occured gradually over the period of oxygen release. The various metals behaved as in Example 1. In Example 14, Example 13 was repeated but with metal wires in place prior to introduction of the potassium superoxide microcapsules. As the pH gradually increased, there was an onset of gas evolution concurrently with the release from the reaction. The concurrent oxygen production started at about pH 8 and the aqueous hydrogen peroxide oxygen production rate increased continuously up to pH 12. An approximately overall uniform gas delivery resulted since the aqueous hydrogen peroxide rate accelerated as the potassium superoxide rate decreased. Although potassium superoxide was used in these tests, other sources of alkali substantially completely free of metal salts can be used. It is preferred to use water reactive peroxides and superoxides since they liberate desired oxygen. The corresponding salts of potassium, sodium, and lithium are particularly useful because their hydroxides are strong bases and extremely water soluble. The list of metals that catalyze the peroxide decomposition is not complete, and is not meant to be limiting. EXAMPLES 15-35 The present invention of a modular unit having multi-chambers by which the combined ingredients provide a more efficient and compact system than previously possible is not readily treatable in quantitative terms since gas absorption dynamics in an environment of continuously changing conditions involves complex permeation and diffusion controlled parameters, in addition to other variable factors such as breathing rates, contact times with filter surfaces, atmospheric operating pressures, humidity, and changing gas compositions and temperatures. Accordingly, a review of available standard tests showed that existing procedures were inadequate. Therefore, a special test device and method were developed to measure the performance of the materials in a simulated rebreather mode. The test apparatus is shown schematically in FIG. 5 and consists of a closed loop system into which measured air samples can be introduced and recycled through a test filter by means of a pump and in contact with an oxygen level detector. The test method comprises (1) introduction of a fixed amount of respired air to a reservoir 2 through an inlet valve 8, (2) starting recycle pump 1 after shutting inlet valve 8 and recording immediate change in O 2 level, (3) measuring the time and rate of O 2 recovery to ambient levels at a given pump rate. After quasiequilibrium is attained, the air sample is released and a new sample of respired air is injected and recycled as before. A total of 10 respired air injections were used for each filter assembly. Test chemicals were sandwiched between layers of fiberglass mat, and held in the simulator device by an open grid rigid support. Respired air (18.2% O 2 ) at room temperature was the test gas. The rate of recovery of O 2 to ambient level (20.8%) was used as an indicator of filter performance, and changes in the recovery characteristics were used as capacity measures. Recovery rate data are presented in graph form, and other data are given numerically as relative recovery times and total gas transport to achieve target O 2 concentrations. In Example 15, the oxygen generation of uncoated and microencapsulated potassium superoxide over a twenty second span was calculated on the basis of the percentage of oxygen in the air. The data for air injection 1, 3 and 10 are shown in the graphs provided in FIG. 6. From these graphs, it is readily apparent that extended controlled release of oxygen by the microencapulation is achieved even after 10 cycles. In Example 16, anhydrous lithium hydroxide alone (carbon dioxide absorber only) was compared to a system containing anhydrous lithium hydroxide and potassium superoxide microcapsules in a one-to-one weight ratio. The results are shown in FIG. 7. The anhydrous lithium hydroxide alone showed decreased oxygen generating capacity on repeated air injections, while the potassium superoxide microcapsules and anhydrous lithium hydroxide together showed increased capacity due to sustained oxygen release. In Example 17, a test material comprising cationic exchanged zeolite (iron mordenite) was compared against a 5A mole sieve (ued in pressure swing oxygen generation), and a 5A mole sieve which is coated with hydrophobic colloidal silica. As can be seen from the graphs provided in FIG. 8, coating the 5A mole sieve with hydrophobic colloidal silica raises its performance to near that of the iron mordenite. In Example 18, a test material comprising iron exchanged mordenite was compared to a test material comprising both iron exchanged mordenite and potassium superoxide microcapsules. The results are shown in FIG. 9. A comparison of the two sets of curves shows that the combination of iron mordenite and microencapsulated potassium superoxide gives lesser loss in immediate oxygen level on respired air injection and faster recovery to ambient conditions. Additive results from this combination of materials would be expected to yield curves similar to that for microencapsulated superoxides alone. These findings are novel and not predicted. These results were confirmed by the further test results provided by Examples 19-27 which provide the relative recovery rates for the above-mentioned test materials for raising the oxygen level from 18.2 percent (corresponding to the oxygen level in respired air) to 19.5 percent. The results are shown in Table 5. Examples 28-35, provide the amount of respired air necessary to achieve 19.5 percent, 20 percent and 21 percent oxygen levels for certain of the above-mentioned test materials. The results are shown in Table 6. In addition, these results indicate that there is no essential differences by this test procedure between copper and iron as the heavy metal cation exchanged into mordenite. This result conflicts with literature references which suggest that the iron zeolites provide better selective gas absorption than the copper zeolites. Also, the microencapsulated potassium superoxide results in Table 6 show that there were lower total gas transport requirements for the gradual oxygen release to reach 21 percent (ambient air) oxygen levels than the other tested materials. TABLE 5______________________________________RELATIVE TIME.sup.7 TO RAISE O.sub.2 FROM 18.2% TO 19.5%EXAMPLE MATERIAL SECONDS______________________________________19 5A Mole Sieve.sup.8 30020 5A Mole Sieve w/1.5% TS-720.sup.1 15021 Fe Mordenite.sup.2 15022 Cu Mordeniie.sup.3 15023 Anhydr. LiOH 10024 KO.sub.2 Microcapsules 10025 Fe Mordenite/KO.sub.2 Microcaps.sup.4 2026 Fe Mordenite/KO.sub.2 Microcaps/Anh. 20 LiOH.sup.527 Anh. LiOH/KO.sub.2 Microcaps.sup.6 80______________________________________ .sup.1 Cabot Hydrophobic Colloidal Silica .sup.2 Cation Exchanged with Fe(NO.sub. 3).sub.3 .sup.3 Cation Exchanged with Cu(NO.sub.3).sub.2 .sup.4 1/1 Weight Ratio .sup.5 1/1/1 Weight Ratio .sup.6 1/1 Weight Ratio .sup.7 Pump Rate = 8 Secs/Cycle .sup.8 Union Carbide 5AMG (Calcium Zeolite) TABLE 6______________________________________RESPIRED AIR (LITERS).sup.1CYCLED THROUGH FILTER TO REACHOR EXCEED 19.5%, 20% and 21% OXYGEN LEVELSEXAMPLE MATERIAL 19.5% O.sub.2 20% O.sub.2 21% O.sub.2______________________________________28 5A Mole Sieve 5-7.5 10 1029 5A Mole Sieve 2.5 3.75 7.5 w/1.5% TS-72030 Fe Mordenite 1.25 2.5 7.531 Cu Mordenite 1.25 2.5 7.532 KO.sub.2 Microcaps 1-1.25 2.0 5.033 Anh. LiOH 1-1.25 3.75 7.534 KO.sub.2 Microcaps/ 1 2-2.5 5.0 Anh. LiOH35 Fe Mordenite/ 0.25 0.25-0.50 1.75-2.0 KO.sub.2 Microcaps______________________________________ Pump Rate = 8 Secs/Cycle .sup.1 18.2% O.sub.2 Although the primary focus of the present invention has been directed to respirator applications, it is contemplated that various aspects of the present invention, taken both individually and together, may be applied to many other applications. For example, the controlled gas absorption/release mechanisms of the present invention may be used for removal of toxic gases such as ammonia, carbon monoxide, sulfur dioxide and chlorine gas, and for removal of corrosive vapors such as hydrogen fluoride, hydrogen chloride, and sulfur trioxide. It may also be used for fruit ripening (release of ethylene) and water purification. In addition, it is contemplated this aspect of the present invention is suitable for use in fire extinguishers (for carbon dioxide, halon, etc.) The controlled hydrophobicity aspects of the present invention may be used for inorganic cements, mortars and plastics, and for moisture reactives such as carbides, hydroxides and the like. It may also be used for gas absorption from aqueous or high humidity sources. Finally, the moisture activated microcapsules of the present invention may also be used for other exo- and endothermic devices as well as for insecticides, fungicides, and the like. The examples provided above are not meant to be exclusive. Many other variations of the present invention would be obvious to those skilled in the art, and are contemplated to be within the scope of the appended claims.

Apparatuses and methods for selectively absorbing undesirable organic and inorganic vapors and gases from ambient air while providing oxygen level enhancement of the treated air are disclosed.

BACKGROUND OF THE INVENTION 1. Field of the Inventions This invention relates to scalable multistage switching networks, specifically to the in-service method of adding one or more stages to a scalable multistage switching network. 2. Background Information The addition of an extra stage to the design of a multistage interconnection network has numerous benefits to a switching network. The extra stage can be used to add fault tolerance. For example, FIG. 1 depicts an extra stage cube network which comprises extra stage 102 and hypercube network 104 . If a failure occurs in a connection within the hypercube network, the extra stage can be used to route traffic around the fault. Traditionally, in an extra stage cube network the extra stage is activated only upon the detection of a fault. Huang showed in U.S. Pat. No. 5,841,775, issued on Nov. 24, 1998 entitled “Scalable Switching Network” which is hereby incorporated by reference as if set forth in full, that in a redundant blocking compensated cyclic group (RBCCG) network extra rows can be added to the network to give fault tolerance and blocking tolerance to a switching network, by introducing additional paths within the network. Unlike the extra stage cube network, the extra rows in the RBCCG network are active at all times. With a proper routing algorithm, the network can automatically detect and reroute around any faults introduced by either a broken connection or a broken switching element. In networks such as the RBCCG network as well as others, the degree of fault tolerance and blocking tolerance is often related to the number of extra stages within the network. As a result, there is a need to upgrade a network by adding stages. There are several approaches to upgrades. In a “system down” upgrade where the network is shutdown, all connections between switching elements that need to be made in accordance to the desired post-upgrade topology can be made in any order at any time. For example, all connections can be disconnected and then new connections can be made in accordance with the desired post-upgrade topology. The network can then be restarted once the new post-upgrade topology is implemented. The draw back to this method is that the network is unusable during the upgrade process. Prasad in U.S. Pat. No. 6,049,542, issued on Apr. 11, 2000 entitled “Scalable Multistage Interconnection Network Architecture and Method for Performing In-service Upgrade Thereof,” teaches an upgrade where a core section of switching elements can be “hot-swapped” out for an upgrade core section. By the use of a hot-swap, the network is in service during the upgrade. The draw back to this method is that multiplexers for use in the hot-swap must be in place. Additionally, a core section of switching elements must be taken out of service, so as more stages are desired, more hardware must be removed. For example, initially there might be one stage, which is then swapped for three stages, so initially one stage is removed. Then the three core stages might later be upgraded to five stages, leaving the three old stages removed. Even with reuse of hardware, this method is not economical as more and more stages are involved. Furthermore, this method is not readily compatible with other modes of upgrade such as a width upgrade or a fanout upgrade, which are available for some forms of switching networks such as described by Lu in U.S. patent application Ser. No. 10/074,174 filed on Feb. 10, 2002 entitled “Width Upgrade for a Scalable Switching Network”, which is hereby incorporated by reference as if set forth in full (henceforth referred to as the '174 application), and U.S. patent application Ser. No. 10/075,086 filed on Feb. 10, 2002 entitled “Fanout Upgrade for a Scalable Switching Network”, which is hereby incorporated by reference as if set forth in full, Lu in U.S. patent application Ser. No. 09/897,263, filed on Jul. 2, 2001 entitled “Row Upgrade for a Scalable Switching Network” which is hereby incorporated by reference as if set forth in full, henceforth referred to as the '263 application, teaches an upgrade through the addition of extra stages in the middle of a redundant multistage interconnection network. As an example, FIG. 2A depicts a 24-port RBCCG switching network. In accordance with the '263 application, an insertion point between stage 202 and 204 is selected. Conceptually, as shown in FIG. 2B , new stage 206 and interconnection network 210 a can be inserted between stage 202 and interconnection network 210 . Although in reality, connections within interconnection network 210 have been disconnected and reformed as interconnection network 210 b . Equivalently, new stage 206 could have been inserted between interconnection network 210 and stage 204 , resulting in interconnection network 210 a as the reformed instance of interconnection network 210 and interconnection network 210 b as the newly introduced interconnection network. Lu and Huang in U.S. patent application Ser. No. 10/786,874, filed on Feb. 24, 2004 entitled “Systems and Methods for Upgradeable Scalable Switching” which is hereby incorporated by, references as if set forth in full, henceforth referred to as the '874 application, extend the upgrade method to apply other types of network which are not technically redundant multistage network such as the network shown in FIG. 3 which is the result of the orthogonal overlay of two RBCCG networks, also referred to as a double RBCCG overlaid network. The method also is applicable to less traditional multistage networks such as the augmented shuttle exchange network shown in FIG. 4A , which is really a banyan network with additional connections between switching elements within each stage. The upgrade methods described in the '263 application and the '874 application show a two phase process. The first phase inserts the new stage that preserves one adjacent interconnection network topology and produces a second interconnection network with parallel connections. Referring to FIG. 4B , new stage 406 is inserted between stages 402 and 404 . In this example, interconnection network 410 's topology is preserved and interconnection network 412 is introduced which has a set of parallel connections. After new stage 406 is properly inserted, in the second phase, interconnection network 412 is then rewired into the desired post-upgrade topology resulting in interconnection network 414 , as shown in FIG. 4C . Though the new stage is now properly integrated into the new network completing the “row upgrade”, the new network is not complete. Finally, as shown in FIG. 4D , new intra-stage interconnections 416 are added to form an extended form of an augmented shuffle exchange network. Though in this example, intra-stage interconnections 416 are added after the insertion of the new stage, they can be added at any time since they are independent to the “row upgrade”. In fact, since they addition of these interconnections does not cause the breaking of any other connections, it is desirable to add them as soon as feasible as they can be used to bolster the fault tolerance of the network during the upgrade process. The advantage of this upgrade method is that each connection that is broken and each connection that is made can be performed in a sequential manner. The fault tolerance of the network accommodates the broken connections, which occur during the upgrade process. While steps can still occur simultaneously, there is not overriding necessity of a simultaneous switch over as described by Prasad. The intermediary phase of creating a set of parallel connections was designed to simplify the complexity of routing during the upgrade process and to prevent the loss of connectivity between any two external ports during the upgrade process. However, the price of this intermediary phase introduces additional steps during the upgrade process. The methods disclosed herein address the elimination of the intermediary phase in a “stage upgrade”, that is an upgrade where one or more stages are added. Furthermore, in during more complex upgrade procedures where additional stages are added, the methods disclosed herein can be substituted for the splicing phase as described in the '874 application with the added benefit of eliminating additional rewiring steps. BRIEF DESCRIPTION OF THE DRAWINGS Features, aspects, and embodiments of the inventions are described in conjunction with the attached drawings, in which: FIG. 1 is a diagram showing a 16-port extra stage cube network; FIG. 2A is a diagram showing a 24-port 4-stage RBCCG network; FIG. 2B is a diagram showing a 24-port 5-stage RBCCG network upgraded from the network shown in FIG. 2A ; FIG. 3 is a diagram showing a 5×4 RBCCG network overlaid on a 4×5 RBCCG network, also referred to as a 5×4 double RBCCG overlaid network; FIG. 4A is a diagram showing a 32-port augmented shuffle exchange network; FIG. 4B is a diagram showing the network of FIG. 4A after the first phase of the upgrade disclosed in the '263 application; FIG. 4C is a diagram showing the network of FIG. 4A after the extra stage has been incorporated; FIG. 4D is a diagram showing the completed upgraded network after intra-stage connections are added; FIG. 5A is a diagram showing a symbolic representation of a switching element; FIG. 5B is a diagram showing the switching element organized logically with top and bottom ports; FIG. 6 is a diagram showing the relevant components involved in the process of upgrading a 24-port 4-stage RBCCG network to a 24-port 5-stage RBCCG network; FIGS. 7A and 7B are flowcharts describing the stage upgrade procedure; FIGS. 8A-8L is a sequence of diagrams showing the iteration-by-iteration sequence of intermediate topologies that occur during the stage upgrade procedure from a 24-port 4-stage RBCCG network to a 24-port 5-stage RBCCG network; FIG. 9 is a diagram showing a 24-port 4-stage RBCCG network and hardware needed to upgrade it to a 30-port 5-stage RBCCG network; FIG. 10A is a diagram showing the resultant network after the splicing phase described in the '874 application; FIG. 10B and 10C are diagrams showing the resultant network after the first and second rewire phases shown in the '874 application; FIG. 11 is a diagram illustrating the relevant components involved in the process of upgrading a 24-port 4-stage RBCCG network to a 30-port 5-stage RBCCG network; FIGS. 12A-12L is a sequence of diagrams showing the iteration-by-iteration sequence of intermediate topologies that occur during the stage upgrade procedure from a 24-port 4-stage RBCCG network to a 30-port 5-stage RBCCG network with FIG. 12L showing the result of the completed stage upgrade; FIG. 13 is a diagram showing a fully upgraded 30-port 5-stage RBCCG network; FIGS. 14A-14J is a sequence of diagrams showing intermediate topologies that occur during another example of a stage upgrade procedure from a 24-port 4-stage RBCCG network to a 24-port 5-stage RBCCG network where sacrificial connections are made to the inserted hardware prior to performing the upgrade; FIG. 15A is a diagram showing a 24-port 4-stage RBCCG network and hardware needed to upgrade it to a 30-port 6-stage RBCCG network; FIGS. 15B and 15C are diagrams showing the result of iterating on two different selection of ports; FIG. 15D is a diagram showing. the resultant network after the completion of the stage upgrade process; FIG. 15E is a diagram showing a fully upgraded 30-port 6-stage RBCCG network; FIG. 16A is a diagram showing a 24-port 4-stage RBCCG network and a 30-port 4-stage RBCCG network; FIG. 16B is a diagram illustrating the relevant components involved in the process of merging the 24-port 4-stage and the 30-port 4-stage RBCCG network into a 54-port 5-stage RBCCG network; FIG. 16C is a diagram showing the resultant network after the completion of the stage upgrade process; FIG. 16D is a diagram showing the resultant network after the rewiring of the two indicated interconnection networks completing the merging procedure; FIGS. 17A-17D are diagrams showing a stage upgrade of a 32-port Banyan network to an extended Banyan network; FIG. 18 is a diagram showing a 32-port hybrid Banyan network constructed from a Banyan based router and a stage of switching elements; FIGS. 19A-19C are diagrams showing the upgrade procedure in upgrading a 5×4 double RBCCG overlaid network into a 6×4 double RBCCG overlaid network and the role of the stage upgrade procedure; and FIGS. 20A-20C are diagrams showing the upgrade procedure in upgrading a 5×4 double RBCCG overlaid network into a 5×5 double RBCCG overlaid network and the role of the stage upgrade procedure. SUMMARY OF INVENTION A multistage switching network can be upgraded by increasing the number of stages in the network. One or more stages can be inserted by rewiring the interconnection network above and below the insertion point, as prescribed by the desired post-upgrade topology. Both interconnection networks can be rewired concurrently, that is, the rewiring of each interconnection network can comprise a plurality of steps, while these steps can be performed sequentially, the cumulative processes of rewiring each interconnection network need not be performed sequentially. Furthermore, the need to rewire one of the interconnection networks into a set of parallel connections is eliminated. One embodiment of the stage upgrade can iterate through all the connections of the interconnection network above (or equivalently below) the insertion point and disconnects them while reconnecting the two ports on the endpoint of the connection to their respective ports in the new stages. Another aspect of the stage upgrade procedure is that a variety of criteria can be used to select the order of iteration of the connections of the interconnection network above the insertion point. Another aspect of the stage upgrade procedure is that sacrificial connections can be added to improve the fault tolerance of the switching network during the upgrade procedure. One use of the stage upgrade procedures is that it can increase the number of stages in a multistage interconnection network whether redundant or not, while minimizing the disruption to service. Another use of the stage upgrade procedure is to splice in new stages within a complex upgrade such as a simultaneous stage and width upgrade. Another use of the stage upgrade procedure is to merge two multistage networks together. Another use of the stage upgrade procedure is to insert a stage to a double RBCCG overlaid network along either of its axes. These and other features, aspects, and embodiments of the invention are described below in the section entitled “Detailed Description.” DETAILED DESCRIPTION As discussed above, the addition of extra stages introduces additional redundancies. The concern addressed by the first phase in the upgrade process in the '263 application and the '874 application is that during the upgrade process the topology of the network is no longer a well formed topology for which connectivity properties are known. It is feared that an ad hoc approach to a stage upgrade, can introduce a temporary topology during the upgrade process where full connectivity (i.e., the property in which any two external ports can communicate with each other) is lost. Because of the additional redundancy, especially path redundancy, introduced during the stage upgrade process the possibility of losing full connectivity can be avoided by careful choice of upgrade steps, without the need to use a two phase process such as that described in the '263 application and the '874 application. In terms of terminology, a switching element is any component, which can receive data through one port and transmit it through another port in accordance to destination information in that data. Examples of a switching element include a switch and a router. In the context of a multistage network or an extended version of multistage networks, such as an overlaid network, ports are labeled according to their topology, for example, top ports, and bottom ports. Though they can be physically implemented in any fashion, labeling is used for logically assigning each port to a location as explained below. FIG. 5A shows a six-port switching element with ports 502 , 504 , 506 , 508 , 510 , and 512 . In a physical embodiment, this can be a router with all the ports in the front panel. FIG. 5B shows the same six-port switching element logically represented for use in a multistage interconnection network. In this representation, ports 502 , 504 , and 506 are designated as top ports and ports 508 , 510 , and 512 are designated as bottom ports. The choice is completely arbitrary if the ports serve as both input and output ports and the networks considered are bidirectional. In a unidirectional network, the choice of top ports and bottom ports can not be so arbitrary. For example, if top ports are input ports and bottom ports are output ports then only input ports can be labeled top ports and only output ports can be labeled bottom ports. For convenience, the ports in the examples are labeled from left to right, starting at 0, so ports 502 , 504 , and 506 are referred to as top port 0 , top port 1 , and top port 2 , respectively. Likewise, ports 508 , 510 , and 512 are referred to as bottom port 0 , bottom port 1 , and bottom port 2 , respectively. The switching elements can have routing capabilities internally, such as a router running a routing protocol such as Open Shortest Path First (OSPF), Border Gateway Protocol (BGP) or Routing Information Protocol (RIP). Alternatively, the switching elements can have the routing designated from an outside source, such as downloading of a routing table from a central server. During the upgrade process, traffic can be diverted away from a port, which is to be disconnected. This can be automatic when a port is disconnected as in the case of a router running a routing protocol, which can detect a failed connection and automatically reroute traffic away from that port. Furthermore, once the routers exchange routing tables, routing paths involving the disconnected port is disregarded. Alternatively, the switching elements can be instructed to divert traffic away from the disconnected port. Furthermore, a skilled artisan can supply to routing instructions to the switching elements, which discards paths involving the disconnected port. To illustrate an embodiment of the stage upgrade process, the example of upgrading the 24-port 4-stage RBCCG network of FIG. 2A is described. FIG. 6 shows stages 202 and 204 of the 24-port 4-stage RBCCG network, new stage 206 , and interconnection network template 620 involved in the upgrade. For this example, the insertion point is selected between stage 202 and interconnection network 210 . New stage 206 is to be inserted. The desired post-upgrade topology of the interconnection network above and below the new stage is shown as template 620 . It should be noted that the pattern shown in template 620 matches interconnection network 210 . For clarity, the placement of potential switching elements in relation to the interconnection network within template 620 are represented by the horizontal lines above and below the interconnection network. As a general observation, when upgrading by stage alone, that is no simultaneous width or fanout upgrade and no reconfiguration of interconnection networks, the desired topology template-should match the interconnection network either above or below the insertion point. The insertion point generally can be any point below the topmost stage, and above the bottommost stage, although path diversity and redundancy tend to be at their greatest in the middle of the switching network. For the purposes of describing the method in detail, the stage above the insertion point is referred to as upper_stage, the stage below the insertion point is referred to as lower_stage, the inserted_stages are referred to as inserted_stages. Ports 602 are referred to as bottom ports of upper_stage, ports 604 are referred to as top ports of lower_stage, ports 606 are referred to as top ports of inserted_stages, ports 608 are referred to as the bottom ports of inserted_stages. In other upgrade examples, more then one stage can be inserted, so top ports of inserted_stages are the top ports of the uppermost stage being inserted, and bottom ports of inserted_stages are the bottom ports of the lowermost stage being inserted. One should note that if the diagram is turned upside down, the roles of top ports of lower_stage and bottom ports of upper_stage are reversed. Likewise, the role of top ports and bottom ports of inserted_stages are reversed. FIG. 7A is a flow chart describing the general form of stage upgrade algorithm. At step 702 , a determination is made as to whether there are any top ports of lower_stage connected to a bottom port of upper_stage (or conversely any bottom port of upper_stage connected to a top port of lower_stage). If not, at step 704 , a determination is made as to whether there are any top ports of lower_stage or bottom ports of upper_stage not connected. If not, the upgrade is complete, if so the upgrade jumps to step 710 . If at step 702 , there is a top port of lower_stage connected to a bottom port of upper_stage, the upgrade proceeds to step 706 . At step 706 , one of the top ports of lower_stage that is connected to a bottom port of upper_stage is selected. At step 708 , the connection between the selected top port of lower_stage and the bottom port of upper_stage to which it is connected is disconnected. In some embodiments of the upgrade process, traffic is diverted from the selected top port and the bottom port to which it is connected, prior to breaking the connection. At step 710 , a determination is made as to whether to proceed to the connection subprocess. This step is intended to offer flexibility in the upgrade process. While the decision made can be to proceed to the connection subprocess or not to proceed. In order to complete the upgrade process, eventually, the upgrade process must proceed to the connection subprocess. If the decision is to not proceed, the process returns to step 702 . Step 712 marks the beginning of the connection subprocess. At step 712 a determination is made as to whether there are any top ports of lower_stage or bottom ports of upper_stage that are not connected. If all top ports of lower_stage and bottom ports of upper_stage are connected, the process returns to step 702 . If there are any top ports of lower_stage or bottom ports of upper_stage that are not connected, one of these ports is selected at step 714 . Each selected port has a corresponding port of inserted_stages as determined by the desired post-upgrade topology. For instance, if a top port of lower_stage were selected, the corresponding port of inserted_stages would be a bottom port of inserted_stages. Conversely if a bottom port of upper_stage were selected, the corresponding port of inserted_stages would be a top port of inserted_stages. In either case, the specific port of inserted_stages is determined by the desired post-upgrade topology. At step 716 , if the port of inserted_stages corresponding to the selected port has a connection to it, for example if a sacrificial connection were added prior to the upgrade procedure, that connection is disconnected. Traffic can be diverted away from the endpoints of that connection. At step 718 , a connection is made between the selected port and the corresponding port of inserted_stages in accordance with the desired post-upgrade topology. In some embodiments of the upgrade process, after the connection is made, traffic is allowed to resume through the two newly connected ports, which might require an active action taken such as updating of a routing table. After the connection is made, the process. returns to step 710 . In practice, if the decision at step 710 is to always proceed to the connection subprocess for every connection broken at step 708 , two connections can be formed during two iterations of the connection subprocess at step 718 . For example, suppose top port of lower_stage, which is labeled “A”, is connected to bottom port of upper_stage, which is labeled “B”. Suppose according to the desired topology of the interconnection network below the bottom ports of lower_stage port “A” is to be connected to bottom port “C” of inserted_stages and according to the desired topology of the interconnection network above the top ports of lower_stage, port “B” is to be connected to top port “D” of inserted_stages. Then one iteration of the upgrade process can look like the following. Port “A” is selected in step 706 . The connection is disconnected from port “B” satisfying step 708 . The connection is then reconnected to port “C” which completes a connection between port “A” and “C”. A new connection is connected between port “B” and port “D”. While the description of step 708 and step 718 call for connections to be disconnected and new connections to be made. In practice, each connection may comprise a physical connection such as an optical fiber. In which case, streamlining can take place by not disconnecting a connection completely, but merely disconnection one end and subsequently moving the disconnected end to another port to establish a new connection. The selection process in step 714 generally is arbitrary if the decision at step 710 is to proceed to the connection subprocess, because the connection process repeats until all connections that can be made are made before breaking another connection at step 708 , so the impact of the choice of connections is minimal. However, the selection process in step 706 should consider the impact of the potential breaking of the selected connection in step 708 would have on the performance of the network, such as path redundancy and full connectivity. Examples of the selection process are described below. FIG. 7B shows a more specific embodiment of the upgrade process. For example, the decision at step 710 is eliminated and the process always proceeds to the connection subprocess. Because of this there are always two connections made in the connection subprocess. The revised algorithm is described in FIG. 7B and begins at step 720 where a determination is made as to whether there are any bottom ports of upper_stage connected to a top port of lower_stage. This is the inverted selection process of step 702 to show the equivalence of using bottom ports of upper_stage as the selection class rather than top ports of lower_stage. If there are none remaining, the stage upgrade is completed. Otherwise, at step 722 one of the bottom ports of upper_stage connected to a top port of lower_stage is selected. For notational convenience, upon selection the following ports are determined, bottom_port is the selected bottom port of upper_stage, top_port is the top port of lower_stage connected to bottom_port, mid_top_port is the corresponding top port of inserted_stages which should be connected to bottom_port in accordance with the desired post-upgrade topology, and mid_bottom port is the corresponding bottom port of inserted_stages which should be connected to top_port in accordance with the desired post-upgrade topology. As an example of these terms, referring to FIG. 6 , suppose bottom port 1 of R( 1 , 1 ) is selected. then bottom_port is bottom port 1 of R( 1 , 1 ) and top_port is top port 1 of R( 2 , 0 ), because top_port is connected to bottom_port. Using template 620 as a guide, bottom_port should be connected to top port 1 of R(N, 0 ) so mid_top_port is top port 1 of R(N, 0 ), and top_port should be connected to bottom port 1 of R(N, 1 ) so mid_bottom_port is bottom port 1 of R(N, 1 ). At step 724 , the connection between bottom_port and top_port is disconnected. At step 726 , any connection, which is connected to mid_top_port, is disconnected. At step 728 , bottom_port is connected to mid_top_port. At step 730 , any connection, which is connected to mid_bottom_port, is disconnected. At step 732 , top_port is connected to mid_bottom_port. The process then repeats by returning to step 720 . It should be noted that at step 716 of FIG. 7A and steps 726 and 730 of FIG. 7B , connections to top ports and bottom ports of lower_stage would only need to be broken if connections exist to them that are not in accordance with the desired post-upgrade topology. One such example is when sacrificial connections are added as described below. If no connections are added to the new stage(s) unless they conform to the desired post-upgrade topology, then steps 716 , 726 and 730 can be eliminated. It should also be clear that the skilled artisan can shuffle the order of some of these steps to yield a workable upgrade process. In FIG. 7B and the examples to follow, detailed steps related to traffic diversion, which are known, to skilled artisans are omitted. For simplicity, the process is described totally in terms of disconnecting a connection and making a connection. However, whenever a connection is broken traffic can be diverted away from those ports connected by the connection, and whenever a new connection is made traffic can be allowed to flow through the new connection. Practical issues such as moving a connection as discussed above can be applied where applicable, but are not described in FIG. 7B and the foregoing examples. Notationally, the switching elements are labeled as “R(stage, column)”, where stage can be a number or “N” for new and column is a number where the columns are numbered starting with 0 from left to right. Also, “R(n,*)” is a shorthand referring to stage n. As mentioned above, ports for each switching element are numbered from 0 starting from left to right. FIGS. 8A-8L show the intermediate steps of upgrading the network shown in FIG. 2A . For clarity, only the stages involved in the upgrade are shown. To show the equivalent roles of top ports of lower_stage and bottom ports of upper_stage, the selection process described here is based on bottom ports of upper_stage. Basically, the selection process scans bottom ports of upper_stage from right to left and selects the first bottom port, which is connected to a top port of lower_stage. In this example, upper_stage is R( 1 ,*), and lower_stage is R( 2 ,*) and the ports are labeled 0 , 1 and 2 from left to right. In FIG. 8A , scanning from right to left, bottom port 2 of switching element R( 1 , 3 ) is the rightmost bottom port of stage R( 1 ,*) connected to a top port of stage R( 2 ,*) so bottom port 2 of switching element R( 1 , 3 ) is selected. The connection between bottom port 2 of switching element R( 1 , 3 ) and top port 2 of switching element R( 2 , 3 ) is disconnected. In accordance with the interconnection network of desired post-upgrade topology above stage R(N,*) shown with template 620 , a connection is made between top port 2 of switching element R( 2 , 3 ) and bottom port 2 of switching element R(N, 3 ) is made. In accordance with the interconnection network of desired post-upgrade topology below stage R(N,*) also shown with template 620 , a connection is made between bottom port 2 of switching element R( 1 , 3 ) and top port 2 of switching element R(N, 3 ). In FIG. 8B , scanning from right to left, bottom port 1 of switching element R( 1 , 3 ) is the rightmost bottom port of stage R( 1 ,*) connected to a top port of stage R( 2 ,*) so bottom port 1 of switching element R( 1 , 3 ) is selected. The connection between bottom port 1 of switching element R( 1 , 3 ) and top port 2 of switching element R( 2 , 2 ) is disconnected. In accordance with the interconnection network of desired post-upgrade topology above stage R(N,*) shown with template 620 , a connection is made between top port 2 of switching element R( 2 , 2 ) and bottom port 1 of switching element R(N, 3 ) is made. In accordance with the interconnection network of desired post-upgrade topology below stage R(N,*) also shown with template 620 , a connection is made between bottom port 1 of switching element R( 1 , 3 ) and top port 2 of switching element R(N, 2 ). In FIG. 8C , scanning from right to left, bottom port 0 of switching element R( 1 , 3 ) is the rightmost bottom port of stage R( 1 ,*) connected to a top port of stage R( 2 ,*) so bottom port 0 of switching element R( 1 , 3 ) is selected. The connection between bottom port 0 of switching element R( 1 , 3 ) and top port 2 of switching element R( 2 , 1 ) is disconnected. In accordance with the interconnection network of desired post-upgrade topology above stage R(N,*) shown with template 620 , a connection is made between top port 2 of switching element R( 2 , 1 ) and bottom port 0 of switching element R(N, 3 ) is made. In accordance with the interconnection network of desired post-upgrade topology below stage R(N,*) also shown with template 620 , a connection is made between bottom port 0 of switching element R( 1 , 3 ) and top port 2 of switching element R(N, 1 ) In FIG. 8D , scanning from right to left, bottom port 2 of switching element R( 1 , 2 ) is the rightmost bottom port of stage R( 1 ,*) connected to a top port of stage R( 2 ,*) so bottom port 2 of switching element R( 1 , 2 ) is selected. The connection between bottom port 2 of switching element R( 1 , 2 ) and top port 2 of switching element R( 2 , 0 ) is disconnected. In accordance with the interconnection network of desired post-upgrade topology above stage R(N,*) shown with template 620 , a connection is made between top port 2 of switching element R( 2 , 0 ) and bottom port 2 of switching element R(N, 2 ) is made. In accordance with the interconnection network of desired post-upgrade topology below stage R(N,*) also shown with template 620 , a connection is made between bottom port 2 of switching element R( 1 , 2 ) and top port 2 of switching element R(N, 0 ). In FIG. 8E , scanning from right to left, bottom port 1 of switching element R( 1 , 2 ) is the rightmost bottom port of stage R( 1 ,*) connected to a top port of stage R( 2 ,*) so bottom port 1 of switching element R( 1 , 2 ) is selected. The connection between bottom port 1 of switching element R( 1 , 2 ) and top port 1 of switching element R( 2 , 3 ) is disconnected. In accordance with the interconnection network of desired post-upgrade topology above stage R(N,*) shown with template 620 , a connection is made between top port 1 of switching element R( 2 , 3 ) and bottom port 1 of switching element R(N, 2 ) is made. In accordance with the interconnection network of desired post-upgrade topology below stage R(N,*) also shown with template 620 , a connection is made between bottom port 1 of switching element R( 1 , 2 ) and top port 1 of switching element R(N, 3 ). In FIG. 8F , scanning from right to left, bottom port 0 of switching element R( 1 , 2 ) is the rightmost bottom port of stage R( 1 ,*) connected to a top port of stage R( 2 ,*) so bottom port 0 of switching element R( 1 , 2 ) is selected. The connection between bottom port 0 of switching element R( 1 , 2 ) and top port 1 of switching element R( 2 , 2 ) is disconnected. In accordance with the interconnection network of desired post-upgrade topology above stage R(N,*) shown with template 620 , a connection is made between top port 1 of switching element R( 2 , 2 ) and bottom port 0 of switching element R(N, 2 ) is made. In accordance with the interconnection network of desired post-upgrade topology below stage R(N,*) also shown with template 620 , a connection is made between bottom port 0 of switching element R( 1 , 2 ) and top port 1 of switching element R(N, 2 ). In FIG. 8G , scanning from right to left, bottom port 2 of switching element R( 1 , 1 ) is the rightmost bottom port of stage R( 1 ,*) connected to a top port of stage R( 2 ,*) so bottom port 2 of switching element R( 1 , 1 ) is selected. The connection between bottom port 2 of switching element R( 1 , 1 ) and top port 1 of switching element R( 2 , 1 ) is disconnected. In accordance with the interconnection network of desired post-upgrade topology above stage R(N,*) shown with template 620 , a connection is made between top port 1 of switching element R( 2 , 1 ) and bottom port 2 of switching element R(N, 1 ) is made. In accordance with the interconnection network of desired post-upgrade topology below stage R(N,*) also shown with template 620 , a connection is made between bottom port 2 of switching element R( 1 , 1 ) and top port 1 of switching element R(N, 1 ). In FIG. 8H , scanning from right to left, bottom port 1 of switching element R( 1 , 1 ) is the rightmost bottom port of stage R( 1 ,*) connected to a top port of stage R( 2 ,*) so bottom port 1 of switching element R( 1 , 1 ) is selected. The connection between bottom port 1 of switching element R( 1 , 1 ) and top port 1 of switching element R( 2 , 0 ) is disconnected. In accordance with the interconnection network of desired post-upgrade topology above stage R(N,*) shown with template 620 , a connection is made between top port 1 of switching element R( 2 , 0 ) and bottom port 1 of switching element R(N, 1 ) is made. In accordance with the interconnection network of desired post-upgrade topology below stage R(N,*) also shown with template 620 , a connection is made between bottom port 1 of switching element R( 1 , 1 ) and top port 1 of switching element R(N, 0 ). In FIG. 8I , scanning from right to left, bottom port 0 of switching element R( 1 , 1 ) is the rightmost bottom port of stage R( 1 ,*) connected to a top port of stage R( 2 ,*) so bottom port 0 of switching element R( 1 , 1 ) is selected. The connection between bottom port 0 of switching element R( 1 , 1 ) and top port 0 of switching element R( 2 , 3 ) is disconnected. In accordance with the interconnection network of desired post-upgrade topology above stage R(N,*) shown with template 620 , a connection is made between top port 0 of switching element R( 2 , 3 ) and bottom port 0 of switching element R(N, 1 ) is made. In accordance with the interconnection network of desired post-upgrade topology below stage R(N,*) also shown with template 620 , a connection is made between bottom port 0 of switching element R( 1 , 1 ) and top port 0 of switching element R(N, 3 ). In FIG. 8J , scanning from right to left, bottom port 2 of switching element R( 1 , 0 ) is the rightmost bottom port of stage R( 1 ,*) connected to a top port of stage R( 2 ,*) so bottom port 2 of switching element R( 1 , 0 ) is selected. The connection between bottom port 2 of switching element R( 1 , 0 ) and top port 0 of switching element R( 2 , 2 ) is disconnected. In accordance with the interconnection network of desired post-upgrade topology above stage R(N,*) shown with template 620 , a connection is made between top port 0 of switching element R( 2 , 2 ) and bottom port 2 of switching element R(N, 0 ) is made. In accordance with the interconnection network of desired post-upgrade topology below stage R(N,*) also shown with template 620 , a connection is made between bottom port 2 of switching element R( 1 , 0 ) and top port 0 of switching element R(N, 2 ). In FIG. 8K , scanning from right to left, bottom port 1 of switching element R( 1 , 0 ) is the rightmost bottom port of stage R( 1 ,*) connected to a top port of stage R( 2 ,*) so bottom port 1 of switching element R( 1 , 0 ) is selected. The connection between bottom port 1 of switching element R( 1 , 0 ) and top port 0 of switching element R( 2 , 1 ) is disconnected. In accordance with the interconnection network of desired post-upgrade topology above stage R(N,*) shown with template 620 , a connection is made between top port 0 of switching element R( 2 , 1 ) and bottom port 1 of switching element R(N, 0 ) is made. In accordance with the interconnection network of desired post-upgrade topology below stage R(N,*) also shown with template 620 , a connection is made between bottom port 1 of switching element R( 1 , 0 ) and top port 0 of switching element R(N, 1 ). In FIG. 8L , scanning from right to left, bottom port 0 of switching element R( 1 , 0 ) is the rightmost bottom port of stage R( 1 ,*) connected to a top port of stage R( 2 ,*) so bottom port 0 of switching element R( 1 , 0 ) is selected. The connection between bottom port 0 of switching element R( 1 , 0 ) and top port 0 of switching element R( 2 , 0 ) is disconnected. In accordance with the interconnection network of desired post-upgrade topology above stage R(N,*) shown with template 620 , a connection is made between top port 0 of switching element R( 2 , 0 ) and bottom port 0 of switching element R(N, 0 ) is made. In accordance with the interconnection network of desired post-upgrade topology below stage R(N,*) also shown with template 620 , a connection is made between bottom port 0 of switching element R( 1 , 0 ) and top port 0 of switching element R(N, 0 ). Since there are no more bottom ports of stage R( 1 ,*) connected to top ports of stage R( 2 ,*) the upgrade process is completed. FIG. 9 shows a 24-port 4-stage RBCCG network, like the one shown in FIG. 2A , and hardware 902 needed to upgrade it to a 30-port 5-stage RBCCG network. Hardware 902 has been preconnected with connections that can be made in accordance with the desired post-upgrade topology. This is described as the pre-connecting phase of the '874 application. In the '874 application, Lu and Huang use the same example to demonstrate a simultaneous width and stage upgrade. FIG. 10A shows the result of the splicing phase which corresponds to the first phase of the stage upgrade procedure of the '263 application. FIG. 10B shows the result of rewiring the interconnection network between stage R( 1 ,*) and stage R(N,*) in accordance with the desired post-upgrade topology, which corresponds to the rewire phase described in the '263 application. FIG. 10C shows the result of rewiring the interconnection network between stage R(N,*) and stage R( 2 ,*). The skilled artisan would note that there are a number of ports, which are disconnected, connected, disconnected and reconnected again, greatly increasing the number of steps required. FIG. 11 shows the stages of the 24-port 4-stage RBCCG network, like the one shown in FIG. 2A , relevant portions of new hardware 902 , and interconnection network template 1106 involved in the upgrade. Ports 602 are referred to as bottom ports of upper_stage, ports 604 are referred to as top ports of lower_stage, ports 1102 are referred to as top ports of inserted_stages, ports 1104 are referred to as the bottom ports of inserted_stages. Template 1106 shows the desired post-upgrade topology of both the interconnection network above and below stage R(N,*). It should be noted that since a simultaneous width and stage upgrade is taking place template 1106 does not match the topology of interconnection network 210 , unlike the example of FIG. 6 . Since the topology of both the interconnection network below and above inserted_stages is changed, care must be taken in selecting the bottom port of upper_stage. The criteria for the selection of the port is based on its impact to the current topology of the network. To simplify the description of the criteria, the term iterating on a selection means the result of disconnecting the connection connected to the selected port, connecting the selected port to a port of inserted_stages in accordance with the desired post-upgrade topology, and connecting the port that was connected to the selected port to a port of inserted_stages in accordance with the desired post-upgrade topology. This term corresponds to a complete iteration of the process outlined in FIG. 7B . The six selection criteria used in this example are listed below. Criterion 1: Iterating on the selected bottom port creates two connections to the same switching element in stage R(N,*). Meeting criterion 1, insures that the topology will not effectively change when iterating on the selection of the bottom port. In the terms of FIG. 7B , a bottom port meets criterion 1 if mid_top_port and mid_bottom_port belong to the same switching element. Criterion 2: Iterating on the selected bottom port creates a connection to a switching element in stage R(N,*) with connections using one side of the switching element (that is uses only top ports or bottom ports) and where the new connection connects to a port on the opposite side of the switching element to the ports used by the existing connections. For example, if only top port 3 of switching element R(N, 2 ) is connected and iterating on a selected bottom port of R(*, 1 ) would produce a connection to a bottom port of switching element R(N, 2 ). That selected bottom port would meet criterion 2. This insures that we limit the number of “dead end” switching elements. Criterion 3: Iterating on the selected bottom port creates a connection to a switching element in stage R(N,*) having four or fewer connections where the number of top ports used exceeds the number of bottom ports used or vice versa and where the new connection connects to a port on the opposite side of the switching element to the side used by the majority of the ports used by the existing connections. For example, if only two top ports and one bottom of switching element R(N, 3 ) are connected and iterating on selected bottom port of R(*, 1 ) would produce a connection to a bottom port of switching element R(N, 3 ). That selected bottom port meet criterion 3. Basically, where the new connection created tends to balance out the port usage on an inserted switching element. Criterion 4: Iterating on the selected bottom port creates a connection to a switching element in stage R(N,*) having exactly two existing connections. Criterion 5: Iterating on the selected bottom port creates a connection to a switching element in stage R(N,*) having exactly four existing connections. Criterion 6: Any bottom port of upper_stage. It is worth noting that these six criteria can be extended to arbitrary fanouts. The highest priority criterion selects bottom ports that when iterated introduce connections to the same switching element in the inserted stage. The next priority criterion are bottom ports when iterated introduce connections which tend to balance both sides of switching elements in terms of connected ports. The next priority which can be intermingled with the preceding one are bottom port when iterated introduce connections to switching elements with the fewest number of connections. The above criteria work best when a single stage is inserted. For multiple stage insertion, it is likely simpler criteria can be used since between these stages interconnection networks should be preconfigured prior to performing the stage upgrade. These preconfigured connections can introduce a great deal of path redundancy during the upgrade process. For the following example, after each iteration, the connections created in that iteration are depicted in the sequences of figures with bold connections. In FIG. 12A , bottom port 2 of switching element R( 1 , 2 ) is selected because iterating on the selection of bottom port 2 of switching element R( 1 , 2 ) produces a connection to top port 1 of switching element R(N, 3 ) and a connection to bottom port 1 of switching element R(N, 3 ) meeting criterion 1. The connection between bottom port 2 of switching element R( 1 , 2 ) and top port 2 of switching element R( 2 , 0 ) is disconnected. In accordance with the interconnection network of desired post-upgrade topology above stage R(N,*) shown with template 1106 , a connection is made between top port 2 of switching element R( 2 , 0 ) and bottom port 1 of switching, element R(N, 3 ) is made. In accordance with the interconnection network of desired post-upgrade topology below stage R(N,*) also shown with template 1106 , a connection is made between bottom port 2 of switching element R( 1 , 2 ) and top port 1 of switching element R(N, 3 ). In FIG. 12B , bottom port 1 of switching element R( 1 , 2 ) is selected because it because iterating on the selection of bottom port 1 of switching element R( 1 , 2 ) produces a connection to top port 1 of switching element R(N, 2 ) and a connection to bottom port 2 of switching element R(N, 2 ) meeting criterion 1. The connection between bottom port 1 of switching element R( 1 , 2 ) and top port 1 of switching element R( 2 , 3 ) is disconnected. In accordance with the interconnection network of desired post-upgrade topology above stage R(N,*) shown with template 1106 , a connection is made between top port 1 of switching element R( 2 , 3 ) and bottom port 2 of switching element R(N, 2 ) is made. In accordance with the interconnection network of desired post-upgrade topology below stage R(N,*) also shown with template 1106 , a connection is made between bottom port 1 of switching element R( 1 , 2 ) and top port 1 of switching element R(N, 2 ). In FIG. 12C , bottom port 0 of switching element R( 1 , 0 ) is selected because it because iterating on the selection of bottom port 0 of switching element R( 1 , 0 ) produces a connection to top port 0 of switching element R(N, 0 ) and a connection to bottom port 0 of switching element R(N, 0 ) meeting criterion 1. The connection between bottom port 0 of switching element R( 1 , 0 ) and top port 0 of switching element R( 2 , 0 ) is disconnected. In accordance with the interconnection network of desired post-upgrade topology above stage R(N,*) shown with template 1106 , a connection is made between top port 0 of switching element R( 2 , 0 ) and bottom port 0 of switching element R(N, 0 ). In accordance with the interconnection network of desired post-upgrade topology below stage R(N,*) also shown with template 1106 , a connection is made between bottom port 0 of switching element R( 1 , 0 ) and top port 0 of switching element R(N, 0 ) is made. No more ports meet criterion 1. In FIG. 12D , bottom port 2 of switching element R( 1 , 3 ) is selected because switching element R(N, 1 ) has one connection using bottom port 1 . Iterating on the selection of bottom port 2 of switching element R( 1 , 3 ) produces a connection to top port 2 of switching element R(N, 1 ) meeting criterion 2. The connection between bottom port 2 of switching element R( 1 , 3 ) and top port 2 of switching element R( 2 , 3 ) is disconnected. In accordance with the interconnection network of desired post-upgrade topology above stage R(N,*) shown with template 1106 , a connection is made between top port 2 of switching element R( 2 , 3 ) and bottom port 1 of switching element R(N, 4 ) is made. In accordance with the interconnection network of desired post-upgrade topology below stage R(N,*) also shown with template 1106 , a connection is made between bottom port 2 of switching element R( 1 , 3 ) and top port 2 of switching element R(N, 1 ). No more ports meet criterion 2. In FIG. 12E , bottom port 0 of switching element R( 1 , 3 ) is selected because switching element R(N, 4 ) has one top port in use and two bottom ports in use. Iteration on the selection of bottom port 0 of switching element R( 1 , 3 ) produces a connection to top port 1 of switching element R(N, 4 ) meeting criterion 3. The connection between bottom port 0 of switching element R( 1 , 3 ) and top port 2 of switching element R( 2 , 1 ) is disconnected. In accordance with the interconnection network of desired post-upgrade topology above stage R(N,*) shown with template 1106 , a connection is made between top port 2 of switching element R( 2 , 1 ) and bottom port 2 of switching element R(N, 3 ) is made. In accordance with the interconnection network of desired post-upgrade topology below stage R(N,*) also shown with template 1106 , a connection is made between bottom port 0 of switching element R( 1 , 3 ) and top port 1 of switching element R(N, 4 ). In FIG. 12F , bottom port 0 of switching element R( 1 , 2 ) is selected because switching element R(N, 2 ) has one two ports in use and one bottom port in use. Iteration on the selection of bottom port 0 of switching element R( 1 , 2 ) produces a connection to bottom port 1 of switching element R(N, 2 ) meeting criterion 3. The connection between bottom port 0 of switching element R( 1 , 2 ) and top port 1 of switching element R( 2 , 2 ) is disconnected. In accordance with the interconnection network of desired post-upgrade. topology above stage R(N,*) shown with template 1106 , a connection is made between top port 1 of switching element R( 2 , 2 ) and bottom port 1 of switching element R(N, 2 ) is made. In accordance with the interconnection network of desired post-upgrade topology below stage R(N,*) also shown with template 1106 , a connection is made between bottom port 0 of switching element R( 1 , 2 ) and top port 1 of switching element R(N, 1 ). In FIG. 12G , bottom port 0 of switching element R( 1 , 1 ) is selected because switching element R(N, 1 ) has two top ports in used and one bottom port in used. Iteration on the selection of bottom port 0 of switching element R( 1 , 1 ) produces a connection to bottom port 0 of switching element R(N, 1 ) meeting criterion 3. The connection between bottom port 0 of switching element R( 1 , 1 ) and top port 0 of switching element R( 2 , 3 ) is disconnected. In accordance with the interconnection network of desired post-upgrade topology above stage R(N,*) shown with template 1106 , a connection is made between top port 0 of switching element R( 2 , 3 ) and bottom port 0 of switching element R(N, 1 ) is made. In accordance with the interconnection network of desired post-upgrade topology below stage R(N,*) also shown with template 1106 , a connection is made between bottom port 0 of switching element R( 1 , 1 ) and top port 0 of switching element R(N, 3 ). No more ports meet criterion 3. In FIG. 12H , bottom port 1 of switching element R( 1 , 3 ) is selected because switching element R(N, 0 ) has exactly two ports in use. Iteration on the selection of bottom port 1 of switching element R( 1 , 3 ) produces a connection to top port 2 of switching element R(N, 0 ) meeting criterion 4. The connection between bottom port 1 of switching element R( 1 , 3 ) and top port 2 of switching element R( 2 , 2 ) is disconnected. In accordance with the interconnection network of desired post-upgrade topology above stage R(N,*) shown with template 1106 , a connection is made between top port 2 of switching element R( 2 , 2 ) and bottom port 0 of switching element R(N, 4 ) is made. In accordance with the interconnection network of desired post-upgrade topology below stage R(N,*) also shown with template 1106 , a connection is made between bottom port 1 of switching element R( 1 , 3 ) and top port 2 of switching element R(N, 0 ). In FIG. 12I , because of the previous step, bottom port 2 of switching element R( 1 , 0 ) meets criterion 3 because switching element R(N, 0 ) has two top ports in use and one bottom port in used. Iteration on the selection of bottom port 2 of switching element R( 1 , 0 ) produces a connection to bottom port 2 of switching element R(N, 0 ) meeting criterion 3. The connection between bottom port 2 of switching element R( 1 , 0 ) and top port 0 of switching element R( 2 , 2 ) is disconnected. In accordance with the interconnection network of desired post-upgrade topology above stage R(N,*) shown with template 1106 , a connection is made between top port 0 of switching element R( 2 , 2 ) and bottom port 2 of switching element R(N, 0 ) is made. In accordance with the interconnection network of desired post-upgrade topology below stage R(N,*) also shown with template 1106 , a connection is made between bottom port 2 of switching element R( 1 , 0 ) and top port 0 of switching element R(N, 2 ). No more ports meet criterion 3 or 4. In FIG. 12J bottom port 2 of switching element R( 1 , 1 ) is selected because switching element R(N, 0 ) has exactly four ports in use. Iteration on the selection of bottom port 2 of switching element R( 1 , 1 ) produces a connection to top port 1 of switching element R(N, 0 ) meeting criterion 5. The connection between bottom port 2 of switching element R( 1 , 1 ) and top port 1 of switching element R( 2 , 1 ) is disconnected. In accordance with the interconnection network of desired post-upgrade topology above stage R(N,*) shown with template 1106 , a connection is made between top port 1 of switching element R( 2 , 1 ) and bottom port 0 of switching element R(N, 2 ) is made. In accordance with the interconnection network of desired post-upgrade topology below stage R(N,*) also shown with template 1106 , a connection is made between bottom port 2 of switching element R( 1 , 1 ) and top port 1 of switching element R(N, 0 ). No more ports meet criteria 1-5. In FIG. 12K bottom port 1 of switching element R( 1 , 1 ) is selected meeting criterion 6. The connection between bottom port 1 of switching element R( 1 , 1 ) and top port 1 of switching element R( 2 , 0 ) is disconnected. In accordance with the interconnection network of desired post-upgrade topology above stage R(N,*) shown with template 1106 , a connection is made between top port 1 of switching element R( 2 , 0 ) and bottom port 2 of switching element R(N, 1 ) is made. In accordance with the interconnection network of desired post-upgrade topology below stage R(N,*) also shown with template 1106 , a connection is made between bottom port 1 of switching element R( 1 , 1 ) and top port 0 of switching element R(N, 4 ). No more ports meet criteria 1 - 5 . In FIG. 12L bottom port 1 of switching element R( 1 , 0 ) is selected meeting criterion 6. The connection between bottom port 1 of switching element R( 1 , 0 ) and top port 0 of switching element R( 2 , 1 ) is disconnected. In accordance with the interconnection network of desired post-upgrade topology above stage R(N,*) shown with template 1106 , a connection is made between top port 0 of switching element R( 2 , 1 ) and bottom port 1 of switching element R(N, 0 ) is made. In accordance with the interconnection network of desired post-upgrade topology below stage R(N,*) also shown with template 1106 , a connection is made between bottom port 1 of switching element R( 1 , 0 ) and top port 0 of switching element R(N, 1 ). This completes the stage upgrade or splicing phase of the upgrade procedure in accordance with the new algorithm flowcharted in FIG. 7A and 7B . This results in the same topology as shown in FIG. 10C . It is clear from FIG. 12L that interconnection network 1202 and interconnection network 1204 need to be rewired into the desired post-upgrade topology. Any of the rewiring algorithms taught by Lu and Huang in the '874 application can now be applied to interconnection network 1202 and 1204 resulting in interconnection networks 1302 and 1304 respectively. FIG. 13 shows a completely upgraded 30-port 5-stage RBCCG network. Finally, any new external ports can be activated such as the top ports of switching element R( 0 , 4 ) and the bottom ports of switching element R( 3 , 4 ). While traffic can be passed through those ports during the upgrade, it is not recommended since until the upgrade is complete, the connectivity to and from those new external ports will be limited. This example illustrates how the stage upgrade disclosed can be integrated into a more complex upgrade procedure by replacing the splicing phase described by Lu and Huang in the '874 application. It is worth noting that the six criteria enumerated above is one of countless possibilities As is seen below, different upgrades can call for different criteria. Although generally, criterion 1 or variations of it has proven to provide a method of increasing the redundancy in intermediate topologies during an upgrade with minimal impact on network traffic. Returning to the example of an upgrade from a 24-port 4-stage RBCCG network to a 24-port 5-stage RBCCG network of FIG. 6 . The amount of connectivity within the new hardware is zero. As shown in FIG. 14A , one method to insure additional connectivity is to add sacrificial connectivity to the new hardware. For example, new hardware 1402 has the new switching elements chained, that is a new connection is added between adjacent switching elements. For example, bottom port 2 of switching element R(N, 0 ) is connected to top port 0 of switching element R(N, 1 ). The selection criterion for this example is as follows. Criterion 1 is as above where iteration on the selection leads to new connections to the same switching element without the need for breaking a sacrificial connection. An extension to this could be that if the new connections preserve the original connectivity through a sacrificial path, the extension to the criterion is met. However, because the sacrificial connections will ultimately be broken, the criterion extension is not used. Criterion 2 is met if iteration on the selection does not require a sacrificial connection be broken. Criterion 3 is met by any selection. It should be noted before proceeding to the specifics of the upgrade process, that both the desired interconnection networks above and below R(N,*), in accordance with the desired post-upgrade topology are given by template 620 in FIG. 6 . FIG. 14B shows the resultant topology. after iterating on bottom port 0 of switching element R( 1 , 0 ), bottom port 0 of switching element R( 1 , 2 ) and bottom port 2 of switching element R( 1 , 3 ). The three ports meeting criterion 1. The connection between bottom port 2 of switching element R( 1 , 3 ) and top port 2 of switching element R( 2 , 3 ) is disconnected. In accordance with the interconnection network of desired post-upgrade topology above stage (N,*) shown with template 620 , a connection is made between top port 2 of switching element R( 2 , 3 ) and bottom port 2 of switching element R(N, 3 ) is made. In accordance with the interconnection network of desired post-upgrade topology below stage R(N,*) also shown with template 620 , a connection is made between bottom port 2 of switching element R( 1 , 3 ) and top port 2 of switching element R(N, 3 ). The connection between bottom port 0 of switching element R( 1 , 2 ) and top port 1 of switching element R( 2 , 2 ) is disconnected. In accordance with the interconnection network of desired post-upgrade topology above stage (N,*) shown with template 620 , a connection is made between top port 1 of switching element R( 2 , 2 ) and bottom port 0 of switching element R(N, 2 ) is made. In accordance with the interconnection network of desired post-upgrade topology below stage R(N,*) also shown with template 620 , a connection is made between bottom port 0 of switching element R( 1 , 2 ) and top port 1 of switching element R(N, 2 ). The connection between bottom port 0 of switching element R( 1 , 0 ) and top port 0 of switching element R( 2 , 0 ) is disconnected. In accordance with the interconnection network of desired post-upgrade topology above stage (N,*) shown with template 620 , a connection is made between top port 0 of switching element R( 2 , 0 ) and bottom port 0 of switching element R(N, 0 ) is made. In accordance with the interconnection network of desired post-upgrade topology below stage R(N,*) also shown with template 620 , a connection is made between bottom port 0 of switching element R( 1 , 0 ) and top port 0 of switching element R(N, 0 ). One should note that bottom port 1 of switching element R( 1 , 1 ) would meet criterion 1 except it would require a connection to be made to port 2 of switching element R(N, 1 ) which currently has a sacrificial connection made to it. There are several alternatives. Bottom port 1 of switching element R( 1 , 1 ) could just be considered a criterion 2 or 3 port depending on the topology at each stage. One alternative is to preconnect bottom port 1 of switching element R(N, 1 ) to top port 0 of switching element R(N, 2 ) prior to the upgrade process. Finally, if the port assignments are logical the labels for bottom ports 1 and 2 of switching element R(N, 1 ) can be exchanged. This is discussed in more detail in the '874 application. For this example, the last option is exercised as shown in FIG. 14C . As a result of the relabelling, bottom port 1 of switching element R( 1 , 1 ) now meets criterion 1. FIG. 14D shows the resultant topology after iterating on bottom port 1 of switching element R( 1 , 1 ). The connection between bottom port 2 of switching element R( 1 , 1 ) and top port 1 of switching element R( 2 , 1 ) is disconnected. In accordance with the interconnection network of desired post-upgrade topology above stage (N,*) shown with template 620 , a connection is made between top port 1 of switching element R( 2 , 1 ) and bottom port 2 of switching element R(N, 1 ) is made. In accordance with the interconnection network of desired post-upgrade topology below stage R(N,*) also shown with template 620 , a connection is made between bottom port 2 of switching element R( 1 , 1 ) and top port 1 of switching element R(N, 1 ). FIG. 14E shows the resultant topology after iterating on bottom ports 0 and 1 of switching element R( 1 , 3 ) and bottom port 1 of switching element R( 1 , 2 ), the ports which meets criterion 2. The connection between bottom port 1 of switching element R( 1 , 3 ) and top port 2 of switching element R( 2 , 2 ) is disconnected. In accordance with the interconnection network of desired post-upgrade topology above stage (N,*) shown with template 620 , a connection is made between top port 2 of switching element R( 2 , 2 ) and bottom port 1 of switching element R(N, 3 ) is made. In accordance with the interconnection network of desired post-upgrade topology below stage R(N,*) also shown with template 620 , a connection is made between bottom port 1 of switching element R( 1 , 3 ) and top port 2 of switching element R(N, 2 ). The connection between bottom port 0 of switching element R( 1 , 3 ) and top port 2 of switching element R( 2 , 1 ) is disconnected. In accordance with the interconnection network of desired post-upgrade topology above stage (N,*) shown with template 620 , a connection is made between top port 2 of switching element R( 2 , 1 ) and bottom port 0 of switching element R(N, 3 ) is made. In accordance with the interconnection network of desired post-upgrade topology below stage R(N,*) also shown with template 620 , a connection is made between bottom port 0 of switching element R( 1 , 3 ) and top port 2 of switching element R(N, 1 ). The connection between bottom port 1 of switching element R( 1 , 2 ) and top port 1 of switching element R( 2 , 3 ) is disconnected. In accordance with the interconnection network of desired post-upgrade topology above stage (N,*) shown with template 620 , a connection is made between top port 1 of switching element. R( 2 , 3 ) and bottom port 1 of switching element R(N, 2 ) is made. In accordance with the interconnection network of desired post-upgrade topology below stage R(N,*) also shown with template 620 , a connection is made between bottom port 1 of switching element R( 1 , 2 ) and top port 1 of switching element R(N, 3 ). Since no ports meet criterion 1 or 2, bottom port 2 of switching element R( 1 , 2 ) is selected. FIG. 14F shows the resultant topology after iterating on the selection. The connection between bottom port 2 of switching element R( 1 , 2 ) and top port 2 of switching element R( 2 , 0 ) is disconnected. The sacrificial connection between bottom port 2 of R(N, 2 ) and top port 0 of R(N, 3 ) is also disconnected. In accordance with the interconnection network of desired post-upgrade topology above stage (N,*) shown with template 620 , a connection is made between top port 2 of switching element R( 2 , 0 ) and bottom port 2 of switching element R(N, 2 ) is made. In accordance with the interconnection network of desired post-upgrade topology below stage R(N,*) also shown with template 620 , a connection is made between bottom port 2 of switching element R( 1 , 2 ) and top port 2 of switching element R(N, 0 ). Because of the previous step bottom port 0 of switching element R( 1 , 1 ) now meets criterion 2. FIG. 14G shows the resultant topology after iterating on bottom port 0 of switching element R( 1 , 1 ). The connection between bottom port 0 of switching element R( 1 , 1 ) and top port 0 of switching element R( 2 , 3 ) is disconnected. In accordance with the interconnection network of desired post-upgrade topology above stage (N,*) shown with template 620 , a connection is made between top port 0 of switching element R( 2 , 3 ) and bottom port 0 of switching element R(N, 1 ) is made. In accordance with the interconnection network of desired post-upgrade topology below stage R(N,*) also shown with template 620 , a connection is made between bottom port 0 of switching element R( 1 , 1 ) and top port 0 of switching element R(N, 3 ). Since no ports meet criterion 1 or 2, bottom port 1 of switching element R( 1 , 1 ) is selected. FIG. 14H shows the resultant topology after iterating on the selection. The connection between bottom port 1 of switching element R( 1 , 1 ) and top port 1 of switching element R( 2 , 0 ) is disconnected. The sacrificial connection between bottom port 1 of R(N, 1 ) and top port 0 of R(N, 2 ) is also disconnected. In accordance with the interconnection network of desired post-upgrade topology above stage (N,*) shown with template 620 , a connection is made between top port 1 of switching element R( 2 , 0 ) and bottom port 1 of switching element R(N, 1 ) is made. In accordance with the interconnection network of desired post-upgrade topology below stage R(N,*) also shown with template 620 , a connection is made between bottom port 1 of switching element R( 1 , 1 ) and top port 1 of switching element R(N, 0 ). Since no ports meet criterion 1 or 2, bottom port 2 of switching element R( 1 , 0 ) is selected. FIG. 14I shows the resultant topology after iterating on the selection. The connection between bottom port 2 of switching element R( 1 , 0 ) and top port 0 of switching element R( 2 , 2 ) is disconnected. The sacrificial connection between bottom port 2 of R(N, 0 ) and top port 0 of R(N, 1 ) is also disconnected. In accordance with the interconnection network of desired post-upgrade topology above stage (N,*) shown with template 620 , a connection is made between top port 0 of switching element R( 2 , 2 ) and bottom port 2 of switching element R(N, 0 ) is made. In accordance with the interconnection network of desired post-upgrade topology below stage R(N,*) also shown with template 620 , a connection is made between bottom port 2 of switching element R( 1 , 0 ) and top port 0 of switching element R(N, 2 ). Bottom port 1 of switching element R( 1 , 0 ) is the last remaining bottom port of switching element R( 1 , 0 ) to be selected. FIG. 14J shows the completed upgrade after iterating on the selection. The connection between bottom port 1 of switching element R( 1 , 0 ) and top port 0 of switching element R( 2 , 1 ) is disconnected. In accordance with the interconnection network of desired post-upgrade topology above stage (N,*) shown with template 620 , a connection is made between top port 0 of switching element R( 2 , 1 ) and bottom port 1 of switching element R(N,*) is made. In accordance with the interconnection network of desired post-upgrade topology below stage R(N,*) also shown with template 620 , a connection is made between bottom port 1 of switching element R( 1 , 0 ) and top port 0 of switching element R(N, 1 ). Although the sacrificial connections add redundancy during the upgrade process, they do introduce additional connection and disconnection of connections increasing the amount of steps required in the upgrade process. The number of sacrificial connections leads to a tradeoff between the robustness of the network during the upgrade process and complexity of the upgrade process itself. FIG. 15A depicts a 24-port 4-stage RBCCG network and hardware 1502 needed to upgrade it to a 30-port 6-stage RBCCG network. Hardware 1502 has been preconnected with connections that can be made in accordance with the desired post-upgrade topology. This is described as the preconnecting phase of the '874 application. It should be noted if the preconnections are performed the stage upgrade greater pathwise redundancy exists during the upgrade process leading to better performance of the network as it is being upgraded. One should also note that in this example, interconnection network 1504 between stage R(N,*) and stage R(N′,*) is a complete interconnection network as prescribed by the desired post-upgrade topology. Notationally, in this example, the bottom ports of inserted_stages are the bottom ports of stage R(N′,*) and the top ports of inserted_stages are the top ports of stage R(N,*). Detailed step by step description of the overall upgrade procedure is omitted here. A skilled artisan can take the description of the previous examples and derived the necessary steps. The criteria for the selection of the bottom ports of upper_stage (or the top ports of lower_stage) can differ from the previous criteria. In the previous example, criterion 1 basically selects any connection, which can be broken and rewired “for free”, that is after iterating on the selection, the topology preserves the connectivity of the original connection. The extended form of criterion 1 is met by a selected port if after iterating on the selection, the resultant topology preserves the connectivity of the original connection to the selected port. Because of the added interconnection network 1504 in hardware 1502 , this extended form of criterion 1 is easier to meet. For example, there is a connection between bottom port 2 of switching element R( 1 , 1 ) and top port 1 of switching element R( 2 , 1 ). FIG. 15B shows the topology resulting from iterating on the selection of bottom port 2 of switching element R( 1 , 1 ). Bottom port 2 of switching element R( 1 , 1 ) is now connected to top port 1 of switching element R(N, 0 ) and top port 1 of switching element R( 2 , 1 ) is connected to switching element R(N′, 2 ). However, because of interconnection network 1504 , Bottom port 2 of switching element R( 1 , 1 ) is still indirectly connected to top port 1 of switching element R( 2 , 1 ), because bottom port 2 of switching, element R( 1 , 1 ) is connected to top port 1 of switching element R(N, 0 ) and bottom port 2 of switching element R(N, 0 ) is connected to top port 0 of switching element R(N′, 2 ) and bottom port 1 of switching element R(N′, 2 ) is connected to top port 1 of switching element R( 2 , 1 ), thus preserving the original connectivity, hence meeting the extended form of criterion 1. Conversely; FIG. 15C shows the topology resulting from iterating on the selection of bottom port 2 of switching element R( 1 , 2 ) that is initially connected to top port 2 of switching element R( 2 , 0 ). Bottom port 2 of switching element R( 1 , 2 ) is now connected to top port 1 of switching element R(N, 3 ) and bottom port 1 of switching element R(N′, 3 ) is now connected to top port 2 of switching element R( 2 , 0 ). However, there is no connection between switching element R(N, 3 ) and switching element R(N′, 3 ). As iterating on the selection of bottom port 2 of switching element R( 1 , 2 ) does not preserver the original connectivity between bottom port 2 of switching element R( 1 , 2 ) and top port 2 of switching element R( 2 , 0 ) and hence does not meet the extended form of criterion 1. Generally speaking, all ports meeting criterion 1 or its extended form, collective referred to as “criterion 1 ports,” should be selected first, because topologically there is minimal impact by making that selection first. The redundancy of the network increases as the stage upgrade process so that iterating on the selection of all criterion 1 ports leads to a more redundant network for supporting the remaining iterations. Because of the larger number of criterion 1 ports in this example and the redundancy added from interconnection network 1504 , after all the iterations on the selection of the criterion 1 ports, the selection of the remaining ports can be arbitrary. FIG. 15D shows the topology upon the conclusion of the stage upgrade or splicing phase. Interconnection networks 1506 and 1508 , which were not involved in the stage upgrade, still require rewiring. Rewiring can be performed using a method such as one of the methods disclosed in the '874 application. FIG. 15E shows the resultant network after the complete upgrade has been performed. Another example of a situation where a stage upgrade can be used is in the situation where two multistage interconnection networks are to be merged. FIG. 16A shows 24-port 4-stage RBCCG network 1602 next to a 30-port 4-stage RBCCG network 1604 . If simply reconfigured to a 54-port 4-stage RBCCG network, the new network will lack path redundancies. As is typical in multistage interconnection networks, when the width of the network increases the path redundancies decrease. The addition of an extra stage counteracts this effect. As a result, rather than merging networks 1602 and 1604 into a 54-port 4-stage RBCCG network, a more practical application is to merge networks 1602 and 1604 into a 54-port 5-stage RBCCG network. FIG. 16B shows the strategy for a stage upgrade, which also merges networks 1602 and 1604 . The insertion point is selected between stage R( 2 ,*) and stage R( 1 ,*) and stage R(N,*) is to be inserted. Template 1606 , shows the interconnection network in the desired post-upgrade topology above and below stage R(N,*). After the completion of the upgrade procedure described above such as that in FIG. 7A or FIG. 7B , the network shown in FIG. 16C is the result. A complete merging is not complete until interconnection networks 1610 and 1612 are rewired into the interconnection networks as specified by the desired post-upgrade topology, which coincides with template 1606 . Using the rewiring process taught by the '174 or '874 applications, interconnection networks 1610 and 1612 can be rewired into interconnection networks 1620 and 1622 as shown in FIG. 16D completing the merging process. FIG. 17A shows a 32-port Banyan network. FIG. 17B shows a 32-port 5-stage generalized Banyan network. Though the Banyan network shown in FIG. 17A is not fault tolerant nor redundant, an upgrade to FIG. 17B is still possible using the methods disclosed here or in the '273 or '874 applications. Because the methods disclosed tend to minimize the disruption to network services, an upgrade of a non-redundant network using the stage upgrade method disclosed here minimizes the amount of service disruption. Because the network is not redundant, connectivity will at times be broken, a fact that is unavoidable in a non-redundant network. Logically, there are a couple of ways to insert the new stage to produce the network topology shown in FIG. 17B . For example, as shown in FIG. 17C , new stage 1720 can be inserted between stage 1702 and interconnection network 1704 . The desired post-upgrade topology of the interconnection network above the inserted stage is shown by template 1722 and the desired post-upgrade topology of the interconnection network below the inserted stage is shown by template 1724 . It should be noted in this case, the topology of interconnection network 1704 is identical to template 1724 . Another way to insert the new stage is to insert new stage 1720 between stage 1702 and interconnection network 1710 as shown in FIG. 17D . The desired post-upgrade topology of the interconnection network above the inserted stage is shown by template 1732 and the desired post-upgrade topology of the interconnection network below the inserted stage is shown by template 1734 . It should be noted in this case the topology of interconnection 1710 is identical to template 1732 . The insertion point of a new stage might be limited by constraints imposed by hardware. For example, FIG. 18 shows a 32-port 5-stage redundant Banyan hybrid having a cyclic group interconnection pattern in interconnection network 1804 . Many router units comprise multistage interconnection networks internally which are not accessible by the network administrator. In the example of FIG. 18 , a network administrator acquires a high power router 1806 , which comprises many internal routers, which he has no access to. Because router 1806 consists of a classic Banyan network, it is susceptible to blocking, especially when subject to isochronous traffic. To alleviate blocking, the network administrator appends stage 1802 of individual routers to form his own redundant switching network. While this improvement has doubled the path redundancy, the network administrator needs more path redundancy to handle greater isochronous traffic, so he wants to upgrade by adding another stage. Since all the routers within router 1806 are sealed, he can not break any of the connections within the unit. As a result physically in this example, the insertion point must be between stage 1802 and router 1806 . Logically, this leaves two choices for an insertion point either between stage 1802 and interconnection network 1804 or between interconnection network 1804 and router 1806 . Once the insertion point is selected, the network administrator can upgrade the network by adding another stage, which can redouble the path redundancy. Another example of the application of the stage upgrade procedure, a 5×4 overlaid switching network is shown in FIG. 19A . Because the network is an overlay of two orthogonal redundant multistage interconnection networks, it can be upgraded by the insertion of a stage when viewed from top to bottom or from left to right. In the example shown the stage is viewed from left to right. New stage 1906 is to be inserted between stage 1902 and, interconnection network 1904 . Any of the techniques described above can be applied. The result of the stage upgrade is shown in FIG. 19B where new stage 1906 has been inserted and with new interconnection network 1908 created as a result of the process. A full upgrade is not complete because interconnection networks 1910 , 1912 , and 1914 need to be rewired to account for the addition of the stage when viewed from top to bottom. This resembles a width upgrade as described by the '174 and '874 applications. When rewired according to the width upgrade procedures, interconnection network 1910 , 1912 , and 1914 in FIG. 19B are transformed into interconnection network 1920 , 1922 , and 1924 completed the upgrade as shown in FIG. 19C . In the example shown in FIG. 20A . The same 5×4 overlaid switching network is upgraded by the insertion of a stage when viewed as a multistage interconnection network when viewed from top to bottom. New stage 2006 is to be inserted between stage 2002 and interconnection network 2004 . Any of the techniques described above can be applied. The result of the stage upgrade is shown in FIG. 20B where new stage 2006 has been inserted and with new interconnection network 2008 created as a result of the process. A full upgrade is not complete because interconnection networks 2010 , 2012 , 2014 , and 2016 need to be rewired to account for the addition of the stage when viewed from left to right. This resembles a width upgrade as described by the '174 and '874 applications. When rewired according to the width upgrade procedures, interconnection network 2010 , 2012 , 2014 , and 2016 in FIG. 20B are transformed into interconnection network 2020 , 2022 , 2024 and 2026 completed the upgrade as shown in FIG. 20C . While certain embodiments of the inventions have been described above, it will be understood that the embodiments described are by way of example only. Accordingly, the inventions should not be limited based on the described embodiments. Thus, the scope of the inventions described herein should only be limited in light of the claims that follow when taken in conjunction with the above description and accompanying drawings.

Extra stages can be added to a switching network to provide pathwise redundancy for fault tolerance and to alleviate traffic blocking. Also, the addition of extra stages can alleviate the loss of pathwise redundancy when the width of switching networks is increased. An in-service method of upgrading a switching network by adding stages allows the addition of redundancy to an existing network without the need to take the network out of service. From an operational point of view, it is often desirable for the upgrade process to be performed by a plurality of sequential steps. However, it is also desirable to minimize the number of steps performed. Because the insertion of extra stages into an existing network calls. for the rewiring of interconnection networks above and below the insertion point, the number of steps can be minimized while also minimizing the impact to network traffic by concurrently rewiring those interconnection networks through a plurality of disconnection and connection steps.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to selected methylol-substituted trihydroxybenzophenones as novel compositions of matter. The present invention relates to selected phenolic resins containing at least one unit which is a condensation product of the selected methylol-substituted trihydroxbenzophenones and selected phenolic monomers. Furthermore, the present invention relates to light-sensitive compositions useful as positive-working photoresist compositions, particularly, those containing these phenolic resins and o-quinonediazide photosensitizers. Still further, the present invention also relates to substrates coated with these light-sensitive compositions as well as the process of coating, imaging and developing these light-sensitive mixtures on these substrates. 2. Description of Related Art Photoresist compositions are used in microlithographic processes for making miniaturized electronic components such as in the fabrication of integrated circuits and printed wiring board circuitry. Generally, in these processes, a thin coating or film of a photoresist composition is first applied to a substrate material, such as silicon wafers used for making integrated circuits or aluminum or copper plates of printed wiring boards. The coated substrate is then baked to evaporate any solvent in the photoresist composition and to fix the coating onto the substrate. The baked coated surface of the substrate is next subjected to an image-wise exposure of radiation. This radiation exposure causes a chemical transformation in the exposed areas of the coated surface. Visible light, ultraviolet (UV) light, electron beam and X-ray radiant energy are radiation types commonly used today in microlithographic processes. After this image-wise exposure, the coated substrate is treated with a developer solution to dissolve and remove either the radiation-exposed or the unexposed areas of the coated surface of the substrate. There are two types of photoresist compositions--negative-working and positive-working. When negative-working photoresist compositions are exposed image-wise to radiation, the areas of the resist composition exposed to the radiation become less soluble to a developer solution (e.g. a cross-linking reaction occurs) while the unexposed areas of the photoresist coating remain relatively soluble to a developing solution. Thus, treatment of an exposed negative-working resist with a developer solution causes removal of the non-exposed areas of the resist coating and the creation of a negative image in the photoresist coating, and thereby uncovering a desired portion of the underlying substrate surface on which the photoresist composition was deposited. On the other hand, when positive-working photoresist compositions are exposed image-wise to radiation, those areas of the resist composition exposed to the radiation become more soluble to the developer solution (e.g. a rearrangement reaction occurs) while those areas not exposed remain relatively insoluble to the developer solution. Thus, treatment of an exposed positive-working resist with the developer solution causes removal of the exposed areas of the resist coating and the creation of a positive image in the photoresist coating. Again, a desired portion of the underlying substrate surface is uncovered. After this development operation, the now partially unprotected substrate may be treated with a substrate-etchant solution or plasma gases and the like. This etchant solution or plasma gases etch the portion of the substrate where the photoresist coating was removed during development. The areas of the substrate where the photoresist coating still remains are protected and, thus, an etched pattern is created in the substrate material which corresponds to the photomask used for the image-wise exposure of the radiation. Later, the remaining areas of the photoresist coating may be removed during a stripping operation, leaving a clean etched substrate surface. In some instances, it is desirable to heat treat the remaining resist layer after the development step and before the etching step to increase its adhesion to the underlying substrate and its resistance to etching solutions. Positive-working photoresist compositions are currently favored over negative-working resists because the former generally have better resolution capabilities and pattern transfer characteristics. Photoresist resolution is defined as the smallest feature which the resist composition can transfer from the photomask to the substrate with a high degree of image edge acuity after exposure and development. In many manufacturing applications today, resist resolution on the order of one micron or less are necessary. In addition, it is generally desirable that the developed photoresist wall profiles be near vertical relative to the substrate. Such demarcations between developed and undeveloped areas of the resist coating translate into accurate pattern transfer of the mask image onto the substrate. One drawback with positive-working photoresists known heretofore is their limited resistance to thermal image deformation. This limitation is becoming an increasing problem because modern processing techniques in semiconductor manufacture (e.g. plasma etching, ion bombardment) require photoresist images which have higher image deformation temperatures (e.g. 150° C.-200° C.). Past efforts to increase thermal stability (e.g. increased molecular weight of the resin) generally caused significant decrease in other desirable properties (e.g. decreased photospeed, diminished adhesion, or reduced contrast, poorer developer dissolution rates), or combinations thereof]. Accordingly, there is a need for improved positive-working photoresist formulations which produce images that are resistant to thermal deformation at temperatures of about 150° to 200° C. while maintaining the other desired properties (e.g. developer dissolution rates) at suitable levels. The present invention is believed to be an answer to that need. SUMMARY OF THE INVENTION Accordingly, the present invention is directed to selected methylol-substituted trihydroxybenzophenones of the formula (I): ##STR3## Moreover the present invention is directed to a phenolic novolak resin comprising at least one unit of formula (II): ##STR4## wherein R and R 1 are individually selected from hydrogen, a lower alkyl group having 1 to 4 carbon atoms and a lower alkoxy having 1 to 4 carbon atoms and said unit or units of formula (II) are made by condensing the methylol-substituted trihydroxybenzophenone of formula (I) with selected phenolic monomer units of formula (III): ##STR5## wherein R and R 1 are defined above. Moreover, the present invention is directed to a light-sensitive composition useful as a positive photoresist comprising an admixture of o-quinonediazide compound and binder resin comprising at least one unit of the formula (II), above; the amount of said o-quinonediazide compound or compounds being about 5% to about 40% by weight and the amount of said binder resin being about 60% to 95% by weight, based on the total solid content of said light-sensitive composition. Still further, the present invention also encompasses the process of coating substrates with these light-sensitive compositions and then imaging and developing these coated substrates. Also further, the present invention encompasses said coated substrates (both before and after imaging) as novel articles of manufacture. DETAILED DESCRIPTION The selected methylol-substituted trihydroxybenzophenones of formula (I) are made by reacting the corresponding trihydroxybenzophenone with formaldehyde under alkaline pH conditions. This reaction is illustrated below in reaction equation (A) wherein the trihydroxybenzophenone is 2,3,4-trihydroxybenzophenone and the alkali employed is NaOH and 5-methylol-2,3,4-trihydroxybenzophenone is made: ##STR6## It should be noted that when 2,3,4-trihydroxybenzophenone is employed as the reactant, the reaction occurs almost completely at the 5-position of the trihydroxyphenyl ring. Other isomeric reactions are insignificant. The reasons for the selectivity of this particular reaction is the relative electronic activation of the 5-position by the hydroxyl groups on the ring; however, the present invention is not to be limited to any particular reactants or process limitation for this particular type of reaction. In making the class of compounds of the present invention, the precursors are preferably reacted at about a 1:1 mole ratio. The preferred reaction temperature is about 40°-50° C. for about 2.5 hours or less at atmospheric pressure. Excess reaction time may cause undesirable polymerization of the intended product. This reaction preferably occurs at an alkaline pH of greater than 7. The pH may be controlled by the addition of specific amounts of alkaline compounds (e.g. NaOH, KOH, Na 2 CO 3 and the like). The intended product may be recovered from the reaction mixture by mixing the reaction mixture with acidified water and thus precipitating the product in solid form. The phenolic resins containing one or more units of formula (II) above are preferably made by reacting the methylol-substituted trihydroxybenzophenone of formula (I), above, and the selected phenolic monomers having units of formula (III) with formaldehyde under usual novolak-making conditions. Generally, this reaction occurs in the presence of an acid catalyst. Suitable acid catalysts include those commonly employed in acid condensation-type reactions such as HCl, H 3 PO 4 , H 2 SO 4 , oxalic acid, maleic acid, maleic anhydride and organic sulfonic acids (e.g. p-toluene sulfonic acid). The most preferred acid catalyst is oxalic acid. Generally, it is also preferred to carry out the condensation reaction of compounds of formulae (I) with (III) either simultaneously or after the novolak polymerization in the presence of an aqueous medium or an organic solvent. Suitable organic solvents include ethanol, tetrahydrofuran, cellosolve acetate, 1-methoxy-2-propanol and 2-ethoxy ethanol. Preferred solvents are water-soluble solvents such as ethanol, 1-methoxy-2-propanol and 2-ethoxy ethanol. The mole ratio of the methylol-substituted trihydroxybenzophenone to the total of the other phenolic compounds (preferably, a combination of meta-and para-cresols) is generally from about 0.1:99.9 to 20:80; more preferably, about 5:95 to about 10:90. The methylolated trihydroxybenzophenone of formula (I) predominately reacts in the para-position on the phenolic molecules as illustrated in formula (III), above. For example, this trihydroxybenzophenone compound will predominately react with phenol or orthoor meta-cresol, but less favorably with para-substituted phenolic molecules. The thus prepared novolaks containing the units of formula (II), above, have showed greater dissolution rates in aqueous alkaline developers than corresponding novolaks prepared without these units. Furthermore, light-sensitive compositions prepared with novolaks containing these units of formula (II) also showed good thermal stability due to their higher molecular weight and high resolution images. It is also believed that the presence of the units of formula (II) in the novolak resin significantly reduce the degree of branching of the novolak and provide unhindered hydroxyl (OH) groups for improved solubility properties and chemical reactivity. In making the present class of resins, the precursors, namely, the trihydroxybenzophenones of formula (I) and the phenolic monomers (most preferably, a mixture of meta- and para-cresols) are preferably placed in a reaction vessel with formaldehyde. The reaction mixture usually also contains an acid catalyst and solvent as noted above. The mixture is then preferably heated to a temperature in the range from about 60° C. to about 120° C., more preferably from about 65° C. to about 95° C., for both the novolak-forming condensation polymerization reaction and the separate phenolic resin-trihydroxybenzophenone condensation reaction to occur. If an aqueous medium is used instead of an organic solvent, the reaction temperature is usually maintained at reflux, e.g. about 95° to 110° C. The reaction time will depend on the specific reactants used and the ratio of formaldehyde to phenolic monomers. The mole ratio of formaldehyde to total phenolic moieties is generally less than about 1:1. Reaction times from 3 to 20 hours are generally suitable. Alternatively, the trihydroxybenzophenones of formula (I) may be first reacted to the phenolic monomers of formula (III) without the presence of formaldehyde. In such cases, the condensation product of formula (II) is made and such condensation products may then be reacted with formaldehyde along with other phenolic monomers to make the novolak resins of the present invention. The most preferred methylol-substituted trihydroxybenzophenone is 5-methylol-2,3,4-trihydroxybenzophenone as shown above in formula (A). The most preferred phenolic monomers is a mixture of meta-cresol and para-cresol having a mole ratio ranging from about 70:30 to about 30:70, respectively. Branched and unbranched novolak resins made from this mixture of meta- and para-cresols will thus include the following types of repeated phenolic units: (1) units of formula (II) above; (2) meta-cresol units of the formula (IV), (IVA) and (IVB): ##STR7## and para-cresol units of formula (V): ##STR8## Regardless of the presence or absence of the further units of formulae (IV) and (V), the resins of the present invention preferably have a molecular weight of from about 500 to about 25,000, more preferably from about 750 to about 20,000. The preferred resins have from about 0.1% to about 30%, more preferably about 5% to 10% by moles of the units of formula (II). The above-discussed resins of the present invention may be mixed with photoactive compounds to make light-sensitive mixtures which are useful as positive acting photoresists. The preferred class of photoactive compounds (sometimes called light sensitizers) is o-quinonediazide compounds particularly esters derived from polyhydric phenols, alkylpolyhydroxyphenones, aryl-polyhydroxyphenones, and the like which can contain up to six or more sites for esterification. The most preferred o-quinonediazide esters are derived from 2-diazo-1,2-dihydro-1-oxonaphthlene-4-sulfonic acid and 2-diazo-1,2-dihydro1-oxo-naphthalene-5-sulfonic acid. Specific examples include resorcinol 1,2-naphthoquinonediazide-4-sulfonic acid esters; pyrogallol 1,2-naphthoquinonediazide-5-sulfonic acid esters, 1,2-quinonediazidesulfonic acid esters of (poly)hydroxyphenyl alkyl ketones or (poly)hydroxyphenyl aryl ketones such as 2,4-dihydroxyphenyl propyl ketone 1,2-benzoquinonediazide-4-sulfonic acid esters, 2,4,dihydroxyphenyl hexyl ketone 1,2-naphthoquinonediazide-4-sulfonic acid esters, 2,4-dihydroxybenzophenone 1,2-naphthoquinonediazide-5-sulfonic acid esters, 2,3,4-trihydroxyphenyl hexyl ketone, 1,2-naphthoquinonediazide-4-sulfonic acid esters, 2,3,4-trihydroxybenzophenone 1,2-naphthoquinonediazide4-sulfonic acid esters, 2,3,4-trihydroxybenzophenone 1,2-naphthoquinonediazide-5-sulfonic acid esters, 2,4,6-trihydroxybenzophenone 1,2-naphthoquinonediazide-4-sulfonic acid esters, 2,4,6-trihydroxybenzophenone 1,2-naphthoquinonediazide-5-sulfonic acid esters, 2,2',4,4'-tetrahydroxybenzophenone 1,2-naphthoquinonediazide-5-sulfonic acid esters, 2,3,4,4'-tetrahydroxy-benzophenone 1,2-naphthoquinonediazide-5-sulfonic acid esters, 2,3,4,4'-tetrahydroxybenzophenone 1,2-naphthoquinonehydroxybenzophenonediazide-4-sulfonic acid esters, 2,2',3,4',6'-pentahydroxybenzophenone 1,2-naphthoquinonediazide-5-sulfonic acid esters and 2,3,3',4,4',5'-hexahydroxybenzophenone 1,2-naphthoquinonediazide-5-sulfonic acid esters; 1,2-quinonediazidesulfonic acid esters of bis[(poly)-hydroxyphenyl]alkanes such as bis(p-hydroxyphenyl)methane 1,2-naphthoquinonediazide-4-sulfonic acid esters, bis(2,4-dihydroxyphenyl)methane 1,2-naphthoquinone-diazide-5-sulfonic acid esters, bis(2,3,4-trihydroxy-phenyl)methane 1,2-naphthoquinonediazide-5-sulfonic acid esters, 2,2-bis(p-hydroxyphenyl)propane 1,2-naphthoquinonediazide-4-sulfonic acid esters, 2,2-bis(2,4-dihydroxyphenyl)propane 1,2-naphthoquinonediazide-5-sulfonic acid esters and 2,2-bis(2,3,4-trihydroxyphenyl)propane 1,2-naphthoquinonediazide-5-sulfonic acid esters. Besides the 1,2-quinonediazide compounds exemplified above, there can also be used the 1,2-quinonediazide compounds described in J. Kosar, "Light Sensitive Systems", 339-352 (1965), John Wiley & Sons (New York) or in S. DeForest, "Photoresist", 50, (1975), MacGraw-Hill, Inc. (New York). In addition, these materials may be used in combinations of two or more. Further, mixtures of substances formed when less than all esterification sites present on a particular polyhydric phenol, alkyl-polyhydroxyphenone, arylpolyhydroxyphenone and the like have combined with o-quinonediazides may be effectively utilized in positive acting photoresists. Of all the 1,2-quinonediazide compounds mentioned above, 1,2-naphthoquinonediazide-5-sulfonic acid di-, tri-, tetra-, penta- and hexa-esters of polyhydroxy compounds having at least 2 hydroxyl groups, i.e. about 2 to 6 hydroxyl groups, are most preferred. Among these most preferred 1,2-naphthoquinone5-diazide compounds are 2,3,4-trihydroxybenzophenone 1,2-naphthoquinonediazide-5-sulfonic acid esters, 2,3,4,4'-tetrahydroxybenzophenone 1,2-naphthoquinone-diazide-5-sulfonic acid esters, and 2,2',4,4'-tetrahydroxybenzophenone 1,2-naphthoquinonediazide-5-sulfonic acid esters. These 1,2-quinonediazide compounds may be used alone or in combination of two or more. The proportion of the light sensitizer compound in the light-sensitive mixture may preferably range from about 5 to about 40%, more preferably from about 10 to about 25% by weight of the non-volatile (e.g. non-solvent) content of the light-sensitive mixture. The proportion of total binder resin of this present invention in the light-sensitive mixture may preferably range from about 60 to about 95%, more preferably, from about 75 to 90% of the non-volatile (e.g. excluding solvents) content of the light-sensitive mixture. These light-sensitive mixtures may also contain conventional photoresist composition ingredients such as other resins, solvents, actinic and contrast dyes, anti-striation agents, plasticizers, speed enhancers, and the like. These additional ingredients may be added to the binder resin and sensitizer solution before the solution is coated onto the substrate. Other binder resins may also be added beside the resins of the present invention mentioned above. Examples include phenolic-formaldehyde resins, cresol-formaldehyde resins, phenol-cresol-formaldehyde resins and polvinylphenol resins commonly used in the photoresist art. If other binder resins are present, they will replace a portion of the binder resins of the present invention. Thus, the total amount of the binder resin in the light-sensitive composition will be from about 60% to aout 95% by weight of the total non-volatile solids content of the light-sensitive composition. The resins and sensitizers may be dissolved in a solvent or solvents to facilitate their application to the substrate. Examples of suitable solvents include methoxyacetoxy propane, ethyl cellosolve acetate, n-butyl acetate, xylene, ethyl lactate, propylene glycol alkyl ether acetates, or mixtures thereof and the like. The preferred amount of solvent may be from about 50% to about 500%, or higher, by weight, more preferably, from about 100% to about 400% by weight, based on combined resin and sensitizer weight. Actinic dyes help provide increased resolution on highly reflective surfaces by inhibiting back scattering of light off the substrate. This back scattering causes the undesirable effect of optical notching, especially on a substrate topography. Examples of actinic dyes include those that absorb light energy at approximately 400-460 nm [e.g. Fat Brown B (C.I. No. 12010); Fat Brown RR (C.I. No. 11285); 2-hydroxy-1,4-naphthoquinone (C.I. No. 75480) and Quinoline Yellow A (C.I. No. 47000)] and those that absorb light energy at approximately 300-340 nm [e.g. 2,5-diphenyloxazole (PPO-Chem. Abs. Reg. No. 92-71-7) and 2-(4-biphenyl)-6-phenyl-benzoxazole (PBBO-Chem. Abs. Reg. No. 17064-47-0)]. The amount of actinic dyes may be up to ten percent weight levels, based on the combined weight of resin and sensitizer. Contrast dyes enhance the visibility of the developed images and facilitate pattern alignment during manufacturing. Examples of contrast dye additives that may be used together with the light-sensitive mixtures of the present invention include Solvent Red 24 (C.I. No. 26105), Basic Fuchsin (C.I. 42514), Oil Blue N (C.I. No. 61555) and Calco Red A (C.I. No. 26125) up to ten percent weight levels, based on the combined weight of resin and sensitizer. Anti-striation agents level out the photoresist coating or film to a uniform thickness. Anti-striation agents may be used up to five percent weight levels, based on the combined weight of resin and sensitizer. One suitable class of anti-striation agents is non-ionic silicon-modified polymers. Non-ionic surfactants may also be used for this purpose, including, for example, nonylphenoxy poly(ethyleneoxy) ethanol; octylphenoxy (ethyleneoxy) ethanol; and dinonyl phenoxy poly(ethyleneoxy) ethanol. Plasticizers improve the coating and adhesion properties of the photoresist composition and better allow for the application of a thin coating or film of photoresist which is smooth and of uniform thickness onto the substrate. Plasticizers which may be used include, for example, phosphoric acid tri-(B-chloroethyl)-ester; stearic acid; dicamphor; polypropylene; acetal resins; phenoxy resins; and alkyl resins up to ten percent weight levels, based on the combined weight of rein and sensitizer. Speed enhancers tend to increase the solubility of the photoresist coating in both the exposed and unexposed areas, and thus, they are used in applications where speed of development is the overriding consideration even though some degree of contrast may be sacrificed, i.e. in positive resists while the exposed areas of the photoresist coating will be dissolved more quickly by the developer, the speed enhancers will also cause a larger loss of photoresist coating from the unexposed areas. Speed enhancers that may be used include, for example, picric acid, nicotinic acid or nitrocinnamic acid at weight levels of up to 20 percent, based on the combined weight of resin and sensitizer. The prepared light-sensitive resist mixture, can be applied to a substrate by any conventional method used in the photoresist art, including dipping, spraying, whirling and spin coating. When spin coating, for example, the resist mixture can be adjusted as to the percentage of solids content in order to provide a coating of the desired thickness given the type of spinning equipment and spin speed utilized and the amount of time allowed for the spinning process. Suitable substrates include silicon, aluminum or polymeric resins, silicon dioxide, doped silicon dioxide, silicon resins, gallium arsenide, silicon nitride, tantalum, copper, polysilicon, ceramics and aluminum/copper mixtures. The photoresist coatings produced by the above described procedure are particularly suitable for application to thermally grown silicon/silicon dioxide-coated wafers such as are utilized in the production of microprocessors and other miniaturized integrated circuit components. An aluminum/aluminum oxide wafer can be used as well. The substrate may also comprise various polymeric resins especially transparent polymers such as polyesters and polyolefins. After the resist solution is coated onto the substrate, the coated substrate is baked at approximately 70° C. to 125° C. until substantially all the solvent has evaporated and only a uniform light-sensitive coating remains on the substrate. The coated substrate can then be exposed to radiation, especially ultraviolet radiation, in any desired exposure pattern, produced by use of suitable masks, negatives, stencils, templates, and the like. Conventional imaging process or apparatus currently used in processing photoresist-coated substrates may be employed with the present invention. In some instances, a post-exposure bake at a temperature about 10° C. higher than the soft bake temperature is used to enhance image quality and resolution. The exposed resist-coated substrates are next developed in an aqueous alkaline developing solution. This solution is preferably agitated, for example, by nitrogen gas agitation. Examples of aqueous alkaline developers include aqueous solutions of tetramethylammonium hydroxide, sodium hydroxide, potassium hydroxide, ethanolamine, choline, sodium phosphates, sodium carbonate, sodium metasilicate, and the like. The preferred developers for this invention are aqueous solutions of either alkali metal hydroxides, phosphates or silicates, or mixtures thereof, or tetramethylammonium hydroxide. Alternative development techniques such as spray development or puddle development, or combinations thereof, may also be used. The substrates are allowed to remain in the developer until all of the resist coating has dissolved from the exposed areas. Normally, development times from about 10 seconds to about 3 minutes are employed After selective dissolution of the coated wafers in the developing solution, they are preferably subjected to a deionized water rinse to fully remove the developer or any remaining undesired portions of the coating and to stop further development. This rinsing operation (which is part of the development process) may be followed by blow drying with filtered air to remove excess water. A post-development heat treatment or bake may then be employed to increase the coating's adhesion and chemical resistance to etching solutions and other substances. The post-development heat treatment can comprise the baking of the coating and substrate below the coating's thermal deformation temperature. In industrial applications, particularly in the manufacture of microcircuitry units on silicon/silicon dioxide-type substrates, the developed substrates may then be treated with a buffered, hydrofluoric acid etching solution or plasma gas etch. The resist compositions of the present invention are believed to be resistant to a wide variety of acid etching solutions or plasma gases and provide effective protection for the resist-coated areas of the substrate. Later, the remaining areas of the photoresist coating may be removed from the etched substrate surface by conventional photoresist stripping operations. The present invention is further described in detail by means of the following Examples. All parts and percentages are by weight unless explicitly stated otherwise. EXAMPLE 1 Synthesis of 5-Methylol-2,3,4-trihydroxybenzophenone Employing 2.5 Hours Reaction Time at 40°-47° C. 2,3,4-Trihydroxybenzophenone [300 gm (1.3 moles)] was added to a 3 liter, three neck flask equipped with mechanical agitation, a thermometer, a condenser and an addition funnel. An aqueous solution of sodium hydroxide [208 gm 98% by weight NaOH dissolved in 1 liter of distilled water (5.1 moles NaOH)] was added slowly to the flask. A dark aqueous solution of the trihydroxybenzophenone was formed rapidly. A slight exotherm was observed causing the solution temperature to rise to ˜48° C. An aqueous 36.5% by weight formaldehyde solution [123.3 gm (1.5 moles)] was then added dropwise through the addition funnel at a controlled rate so not to cause the reaction temperature to exceed 50° C. Half the formaldehyde solution was added rapidly in five minutes and the second half over a total of 80 minutes. After addition, the reaction was allowed to proceed for an additional 80 minutes before it was acidified with a dilute 37% aqueous hydrochloric acid solution by weight [513 gm (5.2 moles HCl)]. The change in the pH of the solution to a neutral or slightly acidic was associated with a change in its color to a yellowish orange. The reaction solution was transferred to a larger container filled with 3 liters of distilled water under vigorous agitation. The reaction solution was dripped slowly into the agitated water over 30 minutes duration. A light solid precipitate was formed. The solid product was filtered out and dried in a vacuum oven at 50° C. for about 20 hours to remove substantially all water in the product. The dried product weighed 306.5 gm which represented a 90.7% yield based on a theoretical yield of 338 gm. The structure of the above titled compound was confirmed by infrared spectral analysis and by proton NMR. The observed NMR ratio of the aliphatic hydrogens to the aromatic hydrogens was 0.296. Compared with the theoretical ratio value of 0.33 for this compound the product purity is 87.99 by moles. High pressure liquid chromatography detected the presence of approximately 7% by weight of trihydroxybenzophenone starting material indicating that this was the major impurity. EXAMPLE 2 Synthesis of 5-Methylol-2,3,4-trihydroxybenzophenone Employing 2 Hours Reaction Time at 40°-45° C. 2,3,4-Trihydroxybenzophenone [300 gm (1.3 moles)] was added to a 3 liter, three neck flask equipped with mechanical agitation, thermometer, a condenser and an addition funnel. An aqueous solution of sodium hydroxide [208 gm 98% by weight NaOH dissolved in 1 liter of distilled water (5.1 moles NaOH)] was added slowly to the flask. A dark aqueous solution of the trihydroxybenzophenone was formed rapidly. A slight exotherm was observed causing the solution temperature to rise to ˜45° C. An aqueous 36.5% by weight formaldehyde solution [123.3 gm (1.5 moles)] was then added dropwise through the addition funnel at a controlled rate so not to cause the reaction temperature to exceed 50° C. Half the formaldehyde solution was added over a period of 70 minutes and the second half over a period of 110 minutes. The reaction solution was poured into a larger container filled with 3 liters of distilled water under vigorous agitation. The reaction mixture was acidified with a dilute 37% aqueous hydrochloric acid solution by weight [513 gm (5.2 moles HCl)]. The change in the pH of the solution to a neutral or slightly acidic was associated with the precipitation of the product in the form of a yellowish orange solid particle. The product was filtered out of solution and reslurried in fresh distilled water three times to wash off trace acid as detected by the neutral pH of the last water wash. The product was dried in a vacuum oven at 50° C. for 24 hours to remove substantially all water. The dried product weighed 320 gm which represented a 94.7% yield based on a theoretical yield of 338 gm. The structure of the above titled compound was confirmed by infrared spectral analysis and by proton NMR. The observed NMR ratio of the aliphatic hydrogens to the aromatic hydrogens was 0.265. Compared with the theoretical ratio value of 0.33 for this compound the product purity is 80.3 moles. High pressure liquid chromatography detected the presence of 8.8% by weight of the trihydroxybenzophenone starting material indicating that this was the major impurity. COMPARISON 1 Synthesis of 5-Methylol-2,3,4-Trihydroxybenzophenone Employing 26 Hours Reaction Time and an Excess of Formaldehyde 2,3,4-Trihydroxybenzophenone [200 gm (1.3 moles)] was added to a 3 liter, three neck flask equipped with mechanical agitation, thermometer, a condenser and an addition funnel. An aqueous solution of sodium hydroxide [106.5 gm 98% by weight NaOH dissolved in 690 gm of distilled water (2.6 moles NaOH)] was added slowly to the flask. A dark aqueous solution of the trihydroxybenzophenone was formed rapidly. A slight exotherm was observed causing the solution temperature to raise to ˜42° C. An aqueous 36.5% by weight formaldehyde solution [147 gm (1.79 moles)] was added dropwise through the addition funnel in two parts. The first portion of the formaldehyde solution [86 gm (1.05 moles)] was added over a period of 85 minutes. The reaction was then allowed to continue for 22 hours at 40°-42° C. before adding the section portion of the remaining formaldehyde solution [61 gm (0.74 moles)] over a period of 70 minutes. Approximately 70 minutes later the reaction solution was poured into a larger container filled with 3.3 liters of distilled water under vigorous agitation. The reaction mixture was acidified with glacial acetic acid solution (156 gm) added over a 2 hour period at 28° C. The change in the solution acidity to a pH of 4 associated with the precipitation of the product in the form of a yellowish orange solid particle. The product was filtered out of solution and dried in a vacuum oven at 50° C. for 24 hours to remove substantially all water. The dried product weighed 199.4 gm which represented a 88.25% yield based on a theoretical yield of 226 gm. The structure of the above titled compound was not confirmed by proton NMR analysis. The theoretical NMR ratio of the aliphatic hydrogens to the aromatic hydrogens for this compound is 0.33. The observed NMR ratio of the product of this reaction was 0.08 suggesting a low purity mixture. It is postulated that further condensation of the desired product into higher oligmers may have formed under this extended reaction time and at this higher formaldehyde level. EXAMPLE 3 Mixed Cresol Novolak Synthesis Containing 10 Mole Percent of 5-Methylol-2,3,4-Trihydroxybenzophenone A mixture of m-cresol [248.28 gm (2.3 moles)], p-cresol [165.5 gm (1.53 moles)], a 37.8% aqueous solution of formaldehyde [228 gm (2.86 moles)] and oxalic acid dihydrate [1 gm (0.0081 moles)] was charged into a resin flask. The 1000 ml capacity resin flask used for this reaction was equipped with a mechanical strirrer, a water cooled condenser, a thermometer, an addition funnel, a nitrogen inlet valve and an adequate heating/cooling capacity. The reaction solution was heated up to 60° C. before the addition of the 5-methylol-2,3,4-trihydroxybenzophenone product of Example 1 was started [100 gm dissolved in 285 ml methanol/methoxy-acetoxypropane (about 0.38 moles). This solution was added to the reaction mixture through the addition funnel over a period of 1.5 hours at a temperature range of 100-83° C. The reaction was allowed to continue at reflux temperature for another 1.5 hours before starting atmospheric distillation. The condenser was adjusted from the reflux vertical position to the horizontal distillation tilted position and a receiving flask was installed at its end. The reaction temperature was raised up to 190° C. as the water and formaldehyde were removed. At this point 335.5 gm of aqueous distillate was collected in the receiving flask. The duration of the atmospheric distillation was about 2 hours. Vacuum was applied gradually to remove unreacted cresols. The maximum temperature allowed during the vacuum distillation was 235° C. at 2 mm/Hg of pressure. Most of the residual unreacted cresols were removed rapidly before applying full vacuum. It was necessary to hold full vacuum for one hour and 40 minutes to insure the removal of essentially all unreacted cresol monomers. Nitrogen gas was used to equalize the pressure inside the flask and to avoid the oxidation of the molten novolak. The novolak was poured into an aluminum tray under an atmosphere of nitrogen and was cooled to room temperature. 420 gm of solid novolak was collected containing less than 0.5% cresol monomers by weight. The softening point of the novolak was 142.5-143° C. determined by the ring and ball method, ASTM No. 06.03. EXAMPLE 4 Mixed Cresol Novolak Synthesis Containing 5 Mole Percent of 5-Methylol-2,3,4-Trihydroxybenzophenone A mixture of m-cresol [135.6 gm (1.25 moles)], p-cresol [90.6 gm (0.84 moles)], a 37.7% aqueous solution of formaldehyde [46.6 gm (0.586 moles)], oxalic acid dihydrate [1 gm (0.0081 moles)] and the 5-methylol2,3,4-trihydroxybenzophenone product of Example 1 [30 gm (about 0.13 moles)] were charged into a resin flask. The 1000 ml capacity resin flask used for this reaction was equipped with a mechanical stirrer, a water cooled condenser, a thermometer, a nitrogen inlet valve and an adequate heating/cooling capacity. The reaction solution was heated up to reflux (99°-100° C.) and was allowed to react for three hours before starting atmospheric distillation. The condenser was adjusted from the reflux vertical position to the horizontal distillation tilted position and a receiving flask was installed at its end. The reaction temperature was raised up to 175° C. as the water and formaldehyde were removed. At this point 93 gm of aqueous distillate was collected in the receiving flask. The duration of the atmospheric distillation was about 50 minutes. Vacuum was applied gradually to remove unreacted cresols. The maximum temperature allowed : during the vacuum distillation was 215° C. at 2 mm/Hg of pressure. Most of the residual unreacted cresols were removed rapidly before applying full vacuum, however, it was necessary to hold full vacuum for 25 minutes to insure the removal of essentially all unreacted cresol monomers. Nitrogen gas was used to equalize the pressure inside the flask and to avoid the oxidation of the molten novolak. The novolak was poured into an aluminum tray under an atmosphere of nitrogen and was cooled to room temperature. A total of 65 gm of unreacted cresols was collected in the receiving flask at the end of the vacuum distillation. 216 gm of solid novolak was collected containing less than 0.5% cresol monomers by weight. The softening point of the novolak was 156° C. determined by the ring and ball method, ASTM No. 06.03. EXAMPLE 5 Mixed Cresol Novolak Synthesis Containing 7 Mole Percent of 5-Methylol-2,3,4-Trihydroxybenzophenone A mixture of m-cresol [126 gm (1.17 moles)], p-cresol [84 gm (0.78 moles)], a 36.5% aqueous solution of formaldehyde [121.5 gm (1.483 moles)], oxalic acid dihydrate [1 gm (0.0081 moles)] and the 5-methylol2,3,4-trihydroxybenzophenone product of Example 1 [40 gm (about 0.13 moles)] were charged into a resin flask. The 1000 ml capacity resin flask used for this reaction was equipped with a mechanical stirrer, a water cooled condenser, a thermometer, a nitrogen inlet valve and an adequate heating/cooling capacity. The reaction solution was heated up to reflux (98° C.) and was allowed to react for three hours before starting atmospheric distillation. The condenser was adjusted from the reflux vertical position to the horizontal distillation tilted position and a receiving flask was installed at its end. The reaction temperature was raised up to 200° C. as the water and formaldehyde were removed. The duration of the atmospheric distillation was 1.5 hours. Vacuum was applied gradually to remove unreacted cresols. The maximum temperature allowed during the vacuum distillation was 227° C. at 2 mm/Hg of pressure. Most of the residual unreacted cresols were removed rapidly before applying full vacuum. It was necessary to hold full vacuum for 45 minutes to insure the removal of essentially all unreacted cresol monomers. Nitrogen gas was used to equalize the pressure inside the flask and to avoid the oxidation of the molten novolak. The novolak was poured into an aluminum tray under an atmosphere of nitrogen and was cooled to room temperature. 218 gm of solid novolak was collected containing less than 0.5% cresol monomers by weight. The softening point of the novolak was 160° C. determined by the ring and ball method, ASTM No. 06.03. COMPARISON 2 Mixed Cresol Novolak Synthesis With No 5-Methylol-2,3,4-Trihydroxybenzophenone Added A mixture of m-cresol [607.2 gm (5.62 moles)], p-cresol [404.8 gm (3.75 moles)], a 37.75% aqueous solution of formaldehyde [557 gm (7.03 moles)] and oxalic acid dihydrate [2 gm (0.0162 moles)] was charged into a resin flask. The 2000 ml capacity resin flask used for this reaction was equipped with a mechanical stirrer, a water cooled condenser, a thermometer, an addition funnel, a nitrogen inlet valve and an adequate heating/cooling capacity. The reaction solution was heated up to (100° C.) and was allowed to react at this reflux temperature for four hours before starting the atmospheric distillation. The condenser was adjusted from the reflux vertical position to the horizontal distillation tilted position and a receiving flask was installed at its end. The reaction temperature was raised up to 180° C. as the water and unreacted formaldehyde were removed. At this point 448.5 gm of aqueous distillate was collected in the receiving flask. The duration of the atmospheric distillation was about 2.5 hours. Vacuum was applied gradually to remove unreacted cresols. The maximum temperature allowed during the vacuum distillation was 235° C. at 2 mm/Hg of pressure. Most of the residual unreacted cresols were removed rapidly before applying full vacuum. It was necessary to hold full vacuum for 1.5 hours to insure the removal of essentially all unreacted cresol monomers. Nitrogen gas was used to equalize the pressure inside the flask and to avoid the oxidation of the molten novolak. The novolak was poured into an aluminum tray under an atmosphere of nitrogen and was cooled to room temperature. 838 gm of solid novolak was collected containing less than 0.5% cresol monomers by weight. The softening point of the novolak was 157.5°-157° C. determined by the ring and ball method, ASTM No. 06.03. COMPARISON 3 Mixed Cresol Novolak Synthesis With No 5-Methylol-2,3,4-Trihydroxybenzophenone Added This reaction was carried out in a 500 gallon reactor using a similar cresol mixture as in the above examples (60% m-cresol:40% p-cresol). The formaldehyde molar ratio to cresols was 0.62. The total reaction time employed in this process was 18 hours. In addition, the total duration of the atmospheric distillation was approximately six hours and the vacuum distillation about four hours. The novolak was dissolved in ethyl cellosolve acetate to form a 31.88% solution. This novolak was isolated in the dry solid form by distilling off the solvent from the solution (1887 gm solution) under vacuum at temperatures not exceeding 160° C. in a similar manner to that described above. 710 gm of solid novolak was collected containing less 0.5% cresol monomers by weight. The softening point of the novolak was 135°-138° C. determined by the ring and ball method, ASTM No. 06.03. Table I below provides dissolution times, softening points and relative average molecular weight data of the novolaks prepared in Examples 3, 4, 5 and Comparisons 2 and 3. The data in Table I shows that 5-methylol-2,3,4-trihydroxybenzophenone-containing novolaks exhibit greater solubilities in aqueous alkaline solutions than the comparison mixed cresol novolaks having similar average molecular weights and softening points. In particular, Example 3 has a faster dissolution time than Comparison 3 and Examples 4 and 5 have a faster dissolution times than Comparison 2. The dissolution times were measured for dry one micron thick novolak coatings required to completely dissolve in an aqueous alkaline solution (HPRD-419 developer sold by Olin Hunt Specialty Products, Inc. of West Paterson, N.J.). Such coatings were prepared from novolak solutions in ethyl cellosolve acetate at approximately 25% solids content by means of spin coating. Silicon or silicon dioxide wafers were used as the coating substrates. The spin speeds employed using a Headway spinner were adjusted between 3000 to 6000 RPM to provide equal one micron coatings for all the novolak solutions according to variations in their solution viscosity as a function of their average molecular weights. The coatings were dried in a Blue M hot air circulating oven at 100°-105° C. for thirty minutes. The average molecular weights (MW) and average molecular number (MN) of these novolaks were measured by gel permination chromatography (GPC) under the following conditions: Column Set: 500, 100, 10,000, 100 and 40 Angstroms Solvent: Tetrahydrofuran Detector: Refractive Index Flow Rate: 1.5 ml/min. Injection Volume: 300 ml Calibration: Polystyrene standards TABLE I______________________________________NovolakExample Molecularor Dissolution Softening WeightComparison Time, Sec. Point MW MN______________________________________Example 3 5 143 3163 342Example 4 68 156 19949 738Example 5 20 160 16252 922Comparison 2 260 157 16630 478Comparison 3 10 138 not determined______________________________________ EXAMPLE 6 Preparation of Resist Solution Novolak prepared according to Example 3 (56 gm) was dissolved in an appropriate solvent (144 gm methoxyacetoxypropane) in a 400 ml cylindrical bottle rolled on a high-speed roller for approximately 20 hours. A portion of this solution (158.6 gm) was transferred into a 400 ml size cylindrical amber-colored glass bottle. To this solution 11.375 gm of the photoactive compound and an additional solvent (27.9 gm methoxyacetoxypropane) were added. The bottle was rolled on a high-speed roller for 12 hours at room temperature to dissolve all solids. The photoactive sensitizer was prepared by reacting 2,3,4-trihydroxybenzophenone with naphthoquinone (1,2)-diazide-5-sulphonyl chloride in a 1:2 molar ratio. The sensitizer resulting from this reaction is a mixture of the sulphono mono-, di- and triesters with trihydroxybenzophenone as well as some unesterified trihydroxybenzophenone. The resulting resist solution was subsequently filtered through a 0.2 um pore-size filter using a millipore microfiltration system (100 ml barrel and a 47 mm disk were used). The filtration was conducted in a nitrogen environment under a pressure of 30 pounds per square inch. Approximately 180 ml resist solution was obtained. EXAMPLE 7 Preparation of Resist Solution Novolak prepared according to Example 4 (56 gm) was dissolved in an appropriate solvent (144 gm methoxyacetoxypropane) in a 400 ml cylindrical bottle rolled on a high-speed roller for approximately 20 hours. A portion of this solution (150 gm) was transferred into a 400 ml size cylindrical amber-colored glass bottle. To this solution 10.65 gm of the photoactive compound and an additional solvent (33.7 gm methoxyacetoxypropane) were added. The bottle was rolled on a high-speed roller for 12 hours at room temperature to dissolve all solids. The photoactive sensitizer was prepared by reacting 2,3,4-trihydroxybenzophenone with naphthoquinone (1,2)-diazide-5-sulphonyl chloride in a 1:2 molar ratio. The sensitizer resulting from this reaction is a mixture of the sulphono mono-, di- and triesters with trihydroxybenzophenone as well as some unesterified trihydroxybenzophenone. The resulting resist solution was subsequently filtered through a 0.2 um pore-size filter using a millipore microfiltration system (100 ml barrel and a 47 mm disk were used). The filtration was conducted in a nitrogen environment under a pressure of 30 pounds per square inch. Approximately 175 ml resist solution was obtained. EXAMPLE 8 Preparation of Resist Solution Novolak prepared according to Example 5 (30 gm) was dissolved in an appropriate solvent (70 gm ethyl lactate) in a 200 ml cylindrical bottle rolled on a high-speed roller for approximately 20 hours. A portion of this solution (85 gm) was transferred into a 200 ml size cylindrical amber-colored glass bottle. To this solution 6.375 gm of the photoactive compound and an additional solvent (26.68 gm ethyl lactate) were added. The bottle was rolled on a high-speed roller for 12 hours at room temperature to dissolve all solids. The photoactive sensitizer was prepared by naphthoquinone (1,2)-diazide-5-sulphonyl chloride in a reaction is a mixture of the sulphono mono-, di- and triesters with trihydroxybenzophenone as well as some unesterified trihydroxybenzophenone. The resulting resist solution was subsequently filtered through a 0.2 um pore-size filter using a millipore microfiltration system (100 ml barrel and a 47 mm disk were used). The filtration was conducted in a nitrogen environment under a pressure of 30 pounds per square inch. Approximately 100 ml resist solution was obtained. COMPARISON 4 Preparation of Resist Solution Novolak prepared according to Comparison 2 (98 gm) was dissolved in an appropriate solvent (252 gm methoxyacetoxypropane) in a 400 ml cylindrical bottle rolled on a high-speed roller for approximately 20 hours. A portion of this solution (300 gm) was transferred into a 400 ml size cylindrical amber-colored glass bottle. To this solution 21.52 gm of the photoactive compound and an additional solvent (67.37 gm methoxyacetoxypropane) were added. The bottle was rolled on a high-speed roller for 12 hours at room temperature to dissolve all solids. The photoactive sensitizer was prepared by reacting 2,3,4-trihydroxybenzophenone with naphthoquinone (1,2)-diazide-5-sulphonyl chloride in a 1:2 molar ratio. The sensitizer resulting from this reaction is a mixture of the sulphono mono-, di- and triesters with trihydroxybenzophenone as well as some unesterified trihydroxybenzophenone. The resulting resist solution was subsequently filtered through a 0.2 um pore-size filter using a millipore microfiltration system (100 ml barrel and a 47 mm disk were used). The filtration was conducted in a nitrogen environment under a pressure of 30 pounds per square inch. Approximately 380 ml resist solution was obtained. COMPARISON 5 Preparation of Resist Solution Novolak prepared according to Comparison 3 (98 gm) was dissolved in an appropriate solvent (252 gm methoxyacetoxypropane) in a 400 ml cylindrical bottle rolled on a high-speed roller for approximately 20 hours. A portion of this solution (300 gm) was transferred into a 400 ml size cylindrical amber-colored glass bottle. To this solution 21.52 gm of the photoactive compound and an additional solvent (46.9 gm methoxyacetoxypropane) were added. The bottle was rolled on a high-speed roller for 12 hours at room temperature to dissolve all solids. The photoactive sensitizer was prepared by reacting 2,3,4-trihydroxybenzophenone with naphthoquinone (1,2)-diazide-5-sulphonyl chloride in a 1:2 molar ratio. The sensitizer resulting from this reaction is a mixture of the sulphono mono-, di- and triesters with trihydroxybenzophenone as well as some unesterified trihydroxybenzophenone. The resulting resist solution was subsequently filtered through a 0.2 um pore-size filter using a millipore microfiltration system (100 ml barrel and a 47 mm disk were used). The filtration was conducted in a nitrogen environment under a pressure of 30 pounds per square inch. Approximately 350 ml resist solution was obtained. Photoresist Processing Coating of Photoresist Composition onto a Substrate Photoresist solutions prepared in Examples 6, 7, 8 and Comparison 4 and 5 were spin-coated with a spinner manufactured by Headway Research Inc. (Garland, Tex.) onto a thermally grown silicon/silicon dioxide-coated wafers of 10 cm (four inches) in diameter and 5000 angstroms in oxide thickness. Uniform coatings, after drying, of approximately 1.2 micron in thickness were obtained at spinning velocities ranging from 4,000 to 7,000 RPM for 30 seconds. In order to obtain approximately identical film thicknesses with all resist solutions, adjustments in the employed spin speed were necessary because of the variations in resist viscosities. Table II below provides the relationship between coating film thickness and spin speed for all the resist samples. TABLE II______________________________________Resin Spin Speed Film DryingComposition × 1000 RPM Thickness Condition______________________________________Example 6 4.0 1.23 100/105° C. 5.0 1.08 30' ovenExample 7 6.5 1.21 100/105° C. 30' ovenExample 8 4.0 1.35 100/105° C. 5.0 1.21 30' oven 7.0 1.02 30' oven 4.0 1.44 110/118° C. 5.0 1.31 50" Hot PlateComparison 4 7.0 1.22 100/105° C. 30' ovenComparison 5 5.0 1.21 100/105° C. 30' oven______________________________________ The coated wafers were baked either in an air circulating convection Blue M oven for 30 minutes at 100°-105° C. or on a hot plate for 50 seconds at a temperature range from 100° and 118° C. The dry film thicknesses were measured with a Sloan Dektak II surface profilometer unit. Exposure of Coated Substrates A Perkin-Elmer projection aligner model 340 Micralign was used to provide adequate UV exposures of the above photoresist coated substrates. The spectral output of this instrument covers the range from 310 to 436 nanometers. The light intensity is monitored internally in the instrument. The scan time was varied in order to provide different exposure energies from which the resist sensitivity was determined. A Hunt resolution chromium mask containing groups of lines and spaces, isolated lines and isolated spaces varying in dimensions with minimum features of 1.25 microns. The developed resist features were equal in their dimensions to mask features at the optimum exposure energy. An Ultratech step and repeat 1:1 projection unit, model Ultratech 1000 with a 0.31 numerical aperture was used. This exposure tool provides a narrow spectral output of the G and H Hg lines (436-405 nm). The instrument produces high light intensity and short exposure times measured in milliseconds and controlled accurately by the instrument sensors and the shutter mechanism. Variable exposure energies were used to determine optimum resist exposure energies required to reproduce mask features. The mask used contained groups of lines and spaces, isolated lines and spaces varying in their dimensions with a minimum feature size of 0.75 microns. At optimum exposures the exposed resist image is completely removed by an optimum developer and the image dimension is equal to the corresponding mask image dimension. Optimum developers can be different for each resist formulation. Such developers were determined by obtaining the maximum development contrast between the exposed and the unexposed resist areas where no resist film loss was detected in the unexposed resist areas. Using the above noted mask featuring a group of equal lines and spaces allowed a quick determination of optimum resist exposure energy by microscopic examination of the developed resist images. The accuracy of determining the optimum exposure by this method is within ±mJ/Cm 2 . Development of Exposed Resist Coated Substrates A one minute immersion development process was used to develop exposed resist coatings. Two types of developers were employed, a metal containing sodium based developer and a tetramethylammonium hydroxide based, metal ion free developer at different concentrations adjusted for each resist system. The optimum developer concentration selected for each resist provided the minimum unexposed film thickness loss of the resist coating while maximizing its development rate in the exposed areas, thus obtaining the highest development contrast for each system. The developers used and resist sensitivites are presented in Table III. Immersion Development Process The resist coated wafers produced and exposed according to the preceding discussions were placed on circular Teflon boats and immersed in two liter Teflon containers filled with the appropriate developer (shown in Table III) for the duration of one minute. Agitation during the development was provided by means of nitrogen bubbling distributed evenly throughout the tank. Upon removal the wafers were rinsed in distilled water for one minute and blown dry under a stream of nitrogen gas. Table III below provides the developers employed in processing resist samples of Examples 6, 7, 8 and Comparisons 4 and 5 as well as the resulting resist sensitivities. Waycoat Positive LSI Developer ("LSI") sold by Olin Hunt Specialty Products is a metal ion containing developer and was used diluted with distilled water as indicated in Table III. The metal ion free developer Waycoat MIF Developer ("MIF") is also sold by Olin Hunt Specialty Products, was used diluted with distilled water at the concentrations indicated in Table III below. TABLE III______________________________________ Developer Resist Concentration SensitivityResist % LSI % MIF mJ/Cm.sup.2______________________________________Example 6 20 87-94Example 7 28 260 39.5 155 50 117 62 78 70 47-60Example 8 42 150 30 230 32 170Comparison 4 70 93 39 155Comparison 5 33 58 25.5 71______________________________________ Resist Image Quality & Thermal Deformation Measurements A. Image Quality The quality of resist images were examined after development and prior to the hard baking step. Optical microscopic examination as well as electron scan microscopy were used. The qualitative evaluation of resist images was based on the sharpness of the upper edges of resist lines and spaces, the steepness of their profiles and the smoothness of the resist image surfaces. The slope of the vertical line connecting the top edge of the resist image with its bottom edge was used to quantitatively describe the steepness of the side wall profile. In general, low molecular weight novolaks produce better quality resist images. This was also true for the resist systems of this invention. However, resist image quality compared at both low and high molecular weight based novolaks showed better results with novolak systems of this invention over those made with corresponding comparison novolak. This comparison is provided in Tables IV and V below. TABLE IV______________________________________Low Molecular Weight Novolak Based Resist Systems IMAGE QUALITY Slope Definition ofResist Angle Top Edge Surface______________________________________Example 6 89-90° Very Sharp SmoothComparison 5 85-89° Sharp Smooth______________________________________ TABLE V______________________________________High Molecular Weight Novolak Based Resist System IMAGE QUALITY Slope Definition ofResist Angle Top Edge Surface______________________________________Example 7Mild developers 85° Sharp Smooth(39.5%, 50%and 62% LSI)Aggressive 85° Poor Roughdeveloper poor(70% LSI)Example 8 85-89° Very Sharp SmoothMild developers(42% LSI and30% MIF)Comparison 4Mild developers 85° Poor Smooth(39.5%, 50% poorand 62% LSI)Aggressive 85° Poor Roughdeveloper poor(70% LSI)______________________________________ B. Thermal Deformation The developed resist images were hard baked in a convection, air circulating Blue M oven at 130° C. for 30 minutese after which the resist images were examined for distortion and thermal flow. This examination was carried out by means of optical microscopy and scan electron microscopy. An additional 30 minutes hard bake at 150° C. was applied only to resist images showing no thermal deformation or flow after the first 130° C. hard bake. The resist thermal image deformation was described by the rounding of the image top edges and the decrease in its profile steepness. These observations were more pronounced at the edges of large resist areas than small lines. Resist systems based on the novolaks of this invention exhibited better resistance to thermal flow than the comparison system as shown in Table VI below. TABLE VI______________________________________ Thermal Image Deformation 130° C. 150° C. Edge Decreased Edge DecreasedRESIST Rounding Slope Rounding Slope______________________________________Example 7 No Slight Yes YesExample 8 No No No YesComparison 4 Yes Yes Yes Yes______________________________________

A methylol-substituted trihydroxybenzophenone of the formula (I): ##STR1## This methylol-substituted trihydroxybenzophenone may be reacted with selected phenolic monomers during or after the formation of a phenolic novolak resin thereby said resin having at least one unit of formula (II): ##STR2## wherein R and R 1 are individually selected from hydrogen, a lower alkyl group having 1 to 4 carbon atoms or a lower alkoxy group having 1 to 4 carbon atoms.

CROSS-REFERENCES TO RELATED APPLICATIONS [0001] This application is a continuation of U.S. patent application Ser. No. 10/699,610, filed on Oct. 30, 2003, which is a continuation-in-part of U.S. patent application Ser. No. 10/441,943, filed on May 20, 2003, which is a continuation of U.S. patent application Ser. No. 09/810,918, filed on Mar. 16, 2001, now U.S. Pat. No. 6,591,122, the full disclosures of which are incorporated herein by reference. BACKGROUND [0002] The maintenance of body fluid balance is of foremost concern in the care and treatment of critically ill patients, yet physicians have access to few diagnostic tools to assist them in this vital task. Patients with congestive heart failure, for example, frequently suffer from chronic systemic edema, which must be controlled within tight limits to ensure adequate tissue perfusion and prevent dangerous electrolyte disturbances. Dehydration of infants and children suffering from diarrhea can be life-threatening if not recognized and treated promptly. [0003] The most common method for judging the severity of edema or dehydration is based on the interpretation of subjective clinical signs (e.g., swelling of limbs, dry mucous membranes), with additional information provided by measurements of the frequency of urination, heart rate, serum urea nitrogen SUN/creatinine ratios, and blood electrolyte levels. None of these variables alone, however, is a direct and quantitative measure of water retention or loss. [0004] The indicator-dilution technique, which provides the most accurate direct measure of water in body tissues, is the present de facto standard for assessment of body fluid distribution. It is, however, an invasive technique that requires blood sampling. Additionally, a number of patents have disclosed designs of electrical impedance monitors for measurement of total body water. The electrical-impedance technique is based on measuring changes in the high-frequency (typically 10 KHz-1 MHz) electrical impedance of a portion of the body. Mixed results have been obtained with the electrical-impedance technique in clinical studies of body fluid disturbances as reported by various investigators. The rather poor accuracy of the technique seen in many studies points to unresolved deficiencies of these designs when applied in a clinical setting. [0005] Therefore, there exists a need for methods and devices for monitoring body water fractions which do not suffer from problems due to their being invasive, subjective, inaccurate, and difficult to interpret for the purpose of clinical diagnosis and intervention. SUMMARY [0006] Embodiments of the present invention provide devices and methods that measure body fluid-related metrics using spectrophotometry that may be used to facilitate diagnosis and therapeutic interventions aimed at restoring body fluid balance. The disclosed invention facilitates rapid, non-invasive, and continuous measurement of fractional tissue water, f w . Additional embodiments facilitate intermittent measurement of f w . The specifications of source-detector spacings, wavelength ranges of optical measurement, and algorithms for combining the measurements, provide highly accurate and reproducible methods for determination of f w . [0007] In one embodiment, the present invention provides a device for measuring a body-tissue water content metric as a fraction of the fat-free tissue content of a patient using optical spectrophotometry. The device includes a probe housing configured to be placed near a tissue location which is being monitored; light emission optics connected to the housing and configured to direct radiation at the tissue location; light detection optics connected to the housing and configured to receive radiation from the tissue location; and a processing device configured to process radiation from the light emission optics and the light detection optics to compute the metric where the metric includes a ratio of the water content of a portion of patient's tissue in relation to the lean or fat-free content of a portion of patient's tissue. [0008] In another embodiment, the present invention provides a device for measuring a body-tissue metric using optical spectrophotometry. The device includes a probe housing configured to be placed near a tissue location which is being monitored; light emission optics connected to the housing and configured to direct radiation at the tissue location; light detection optics connected to the housing and configured to receive radiation from the tissue location; and a processing device configured to process radiation from the light emission optics and the light detection optics to compute the metric where the body tissue metric includes a quantified measure of a ratio of a difference between the water fraction in the blood and the water fraction in the extravascular tissue over the fractional volume concentration of hemoglobin in the blood. [0009] In another aspect, the present invention provides a method for measuring a body-tissue water content metric in a human tissue location as a fraction of the fat-free tissue content of a patient using optical spectrophotometry. The method includes placing a probe housing near the tissue location; emitting radiation at the tissue location using light emission optics that are configured to direct radiation at the tissue location. The method also includes detecting radiation using light detection optics that are configured to receive radiation from the tissue location; and processing the radiation from the light emission optics and the light detection optics; and computing the water content metric, where the water content metric, f w l is determined such that f w l = [ ∑ n = 1 N ⁢ p n ⁢   ⁢ log ⁢ { R ⁡ ( λ n ) } ] - [ ∑ n = 1 N ⁢ p n ] ⁢   ⁢ log ⁢ { R ⁡ ( λ N + 1 ) } [ ∑ m = 1 M ⁢ q m ⁢   ⁢ log ⁢ { R ⁡ ( λ m ) } ] - [ ∑ m = 1 M ⁢ q m ] ⁢   ⁢ log ⁢ { R ⁡ ( λ M + 1 ) } , and where: p n and q m are calibration coefficients; R(λ) is a measure of a received radiation at a wavelength; n=1−N and m=1−M represent indexes for a plurality of wavelengths which may consist of the same or different combinations of wavelengths. The method may also include displaying the volume fraction of water on a display device. [0012] In another embodiment, the present invention provides a method for measuring a body-tissue metric in a human tissue location using optical spectrophotometry. The method includes emitting and detecting radiation using light emission and detection optics. In addition, the method includes processing the radiation from light emission and detection optics to compute the metric where the body fluid-related metric is related to a quantified measure of a ratio of a difference between the water fraction in the blood and the water fraction in the extravascular tissue over the fractional volume concentration of hemoglobin in the blood. In one aspect, the metric is a water balance index Q, such that: Q = f w IV - f w EV f h IV = a 1 ⁢   ⁢ ( Δ ⁢   ⁢ R / R ) λ 1 ( Δ ⁢   ⁢ R / R ) λ 2 + a 0 where f w IV and f w EV are the fractional volume concentrations of water in blood and tissue, respectively, f h IV is the fractional volume concentration of hemoglobin in the blood, (ΔR/R) λ is the fractional change in reflectance at wavelength λ, due to a blood volume change in the tissue, and α o and α 1 are calibration coefficients. [0013] In another embodiment, the present invention provides a method for measuring a physiological parameter in a human tissue location. The method includes emitting radiation at the tissue location using light emission optics and detecting radiation using light detection optics. Furthermore, the method includes processing the radiation from the light emission optics and the light detection optics and computing the physiological parameter, where the parameter is determined such that it is equal to [ ∑ n = 1 N ⁢ p n ⁢   ⁢ log ⁢ { R ⁡ ( λ n ) } ] - [ ∑ n = 1 N ⁢ p n ] ⁢   ⁢ log ⁢ { R ⁡ ( λ N + 1 ) } [ ∑ m = 1 M ⁢ q m ⁢   ⁢ log ⁢ { R ⁡ ( λ m ) } ] - [ ∑ m = 1 M ⁢ q m ] ⁢   ⁢ log ⁢ { R ⁡ ( λ M + 1 ) } , and where: p n and q m are calibration coefficients; R(λ) is a measure of a received radiation at a wavelength; n=1−N and m=1−M represent indexes for a plurality of wavelengths which may be the same or different combinations of wavelengths. In one aspect, the physiological parameter is a an oxygen saturation values. In another aspect, the physiological parameter is a fractional hemoglobin concentration. [0014] In yet another embodiment, the present invention provides a method of assessing changes in volume and osmolarity of body fluids near a tissue location. The method includes emitting radiation at a tissue location using light emission optics and detecting radiation using light detection optics that are configured to receive radiation from the tissue location. The method also includes processing the radiation from the light emission optics and the light detection optics; determining a water balance index using the processed radiation; determining a tissue water concentration and analyzing in combination the water balance index and the tissue water concentration to assess changes in volume and osmolarity of body fluids near the tissue location. [0015] For a fuller understanding of the nature and advantages of the embodiments of the present invention, reference should be made to the following detailed description taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS [0016] FIG. 1 is a graph showing tissue water fraction measured on the ear of a pig during an experiment using reflectance measurements at two wavelengths. [0017] FIG. 2 is a graph showing an example regression for prediction of water from reflectances measured at three wavelengths. [0018] FIG. 3 is a graph showing an example regression of a two-wavelength algorithm for determination of the difference between the intravascular and extravascular water fraction from pulsatile reflectances measured at two wavelengths. [0019] FIG. 4 is a diagram of an intermittent-mode version of a fluid monitor. [0020] FIG. 5 is a diagram of a continuous-mode version of a fluid monitor. [0021] FIG. 6 is a block diagram of a handheld apparatus for noninvasive measurement and display of tissue water. [0022] FIG. 7 is a bar graph of water content as a percentage of total and lean mass for men and women between the ages of 20 and 79. [0023] FIG. 8 is a bar graph of water content as a percentage of fat-free and fat-free-bone-free mass for men and women between the ages of 20 and 79. [0024] FIG. 9 is a graph of the correlation between separate fat-free or lean volume water fraction (“f w l ”) measurements on the same patient. DETAILED DESCRIPTION [0025] Embodiments of the present invention overcome the problems of invasiveness, subjectivity, inaccuracy, and difficulty of interpretation for the purpose of clinical diagnosis and intervention, from which previous methods for body fluid assessment have suffered. The method of diffuse reflectance near-infrared (“NIR”) spectroscopy is employed to measure the fraction of water in skin. An increase or decrease in the water content of the skin produces unique alterations of its NIR reflectance spectrum in three primary bands of wavelengths (950-1400 nm, 1500-1800 nm, and 2000-2300 nm) in which none-heme proteins (primarily collagen and elastin), lipids, hemoglobin, and water absorb. According to the results of numerical simulations and experimental studies carried out by the inventors, the tissue water fraction, f w , defined spectroscopically as the ratio of the absorbance of water and the sum of the absorbances of water and other constituents of the tissue, can be measured accurately in the presence of nonspecific scattering variation, temperature, and other interfering variables. [0026] Various constituents of tissue, other than water, are included in the denominator of the ratio used to compute the tissue water fraction according to the embodiments of the present invention. In one embodiment, all of the other major tissue constituents, such as non-heme protein, lipid (“fat”), and hemoglobin, are included, resulting in the computation of the total tissue water fraction, f w T . In other embodiments, certain constituents of the tissue are specifically excluded from the measured tissue water fraction. Spectroscopic methods for the removal of certain tissue constituents from the computation of tissue water fraction are disclosed, either by choosing spectral regions where the absorbance contribution due to these tissue constituents is small, or by appropriately combining spectroscopic measurements made at multiple wavelengths to cancel the absorbance contribution due to these tissue constituents. The use of such spectroscopic methods for removing the absorbance contribution due to lipid from the measurement, thereby providing fractional water in fat-free or lean tissue, f w l , are described. Spectroscopic methods for the exclusion of hemoglobin from the fractional water measurement are also disclosed. [0027] In addition to these spectroscopic methods, physical methods for including and excluding certain tissue constituents are also described in the present invention. By disclosing source-detector separations in the range of 1-5 mm, the present invention targets the dermis, simultaneously avoiding shallow penetration that would be indicative only of the outer dead layer of the skin as well as avoiding deep penetration into the underlying, high fat-content layer, or even further into bone-containing layers. Additional disclosures include the application of pressure at the tissue site of the optical measurement allowing various mobile constituents of the tissue to be included or excluded from the fractional water measurement. In one embodiment, the fractional water is measured before and after the application of pressure at the tissue site, allowing the mobile intravascular portion of the tissue to be included or excluded from the measurement. By this means, measurements of the fractional water content in the intravascular space, f w IV , extravascular space, f w EV , and a difference between the two f w IV -f w EV , is accomplished. In additional embodiments, these measurements are accomplished by photoplethysmography, taking advantage of the natural arterial pulsation of blood through tissue. [0028] In the following detailed descriptions of the embodiments of the invention, the terms “fractional tissue water”, “tissue water fraction”, “water fraction”, and “f w ” all have equivalent meanings and are meant as general terms that include all of the more specific measurements outlined above, including, but not limited to, total tissue water fraction (f w T ), lean tissue water fraction (f w l ), intravascular water fraction (f w EV ), and extravascular water fraction (f w EV ). [0029] In embodiments of the present invention, the apparatus and its associated measurement algorithm are designed according to the following guidelines: 1. To avoid the shunting of light through the superficial layers of the epidermis, the light source and detector in optical reflectance probe have low numerical apertures, typically less than 0.3. 2. The spacing between the source and detector in the probe is in the range of 1-5 mm to confine the light primarily to the dermis. 3. The reflectances are measured at wavelengths greater than approximately 1150 nm to reduce the influence of hemoglobin absorption. Alternatively, reflectances are measured at wavelengths as short as 950 nm, but the influence of hemoglobin absorbance is reduced by appropriately combining measurements of reflectance at multiple wavelengths. Or as a further alternative, the absorbance of hemoglobin is intentionally included in the denominator of the ratio used to compute tissue water fraction. 4. To ensure that the expression that relates the measured reflectances and water content yields estimates of water fraction that are insensitive to scattering variations, the lengths of the optical paths through the dermis at the wavelengths at which the reflectances are measured are matched as closely as possible. This matching is achieved by judicious selection of wavelength sets that have similar water absorption characteristics. Such wavelength sets may be selected from any one of the three primary wavelength bands (950-1400 nm, 1500-1800 nm, and 2000-2300 nm) discussed above. Wavelength pairs or sets are chosen from within one of these three primary bands, and not from across the bands. More particularly the wavelength pair of 1180 and 1300 nm is one such wavelength set where the lengths of the optical paths through the dermis at these wavelengths are matched as closely as possible. 5. To ensure that the expression that relates the measured reflectances and water fractions yields estimates of water fraction that are insensitive to temperature variations, the wavelengths at which the reflectances are measured are chosen to be either close to temperature isosbestic wavelengths in the water absorption spectrum or the reflectances are combined in a way that cancels the temperature dependencies of the individual reflectances. Typically, absorption peaks of various biological tissue constituents may shift with variations in temperature. Here, wavelengths are selected at points in the absorption spectrum where no significant temperature shift occurs. Alternately, by knowing the value of this temperature shift, wavelength sets may be chosen such that any temperature shift is mathematically canceled out when optical measurements are combined to compute the value of a tissue water metric. Such wavelength sets may be selected from any one of the three primary wavelength bands (950-1400 nm, 1500-1800 nm, and 2000-2300 nm) discussed above. Wavelength pairs or sets are chosen from within one of these three primary bands, and not from across the bands. More particularly the wavelength pair of 1180 and 1300 nm are one such pair of temperature isosbestic wavelengths in the water absorption spectrum. 6. The reflectances measured at two or more wavelengths are combined to form either a single ratio, a sum of ratios, a ratio of ratios of the form log[R(λ 1 )/R(λ 2 )], or a ratio of weighted sums of log[R(λ)] terms, in which the numerator depends primarily on the absorbance of water and the denominator depends primarily on the sum of the volume fractions of water and other specific tissue constituents, such that the denominator is equally sensitive to a change in the concentration of any of these specific constituents and water. [0036] Thus, in one embodiment of the present invention the water fraction, f w is estimated according to the following equation, based on the measurement of reflectances, R(λ) at two wavelengths and the empirically chosen calibration constants c 0 and c 1 : f w =c 1 log[ R (λ 1 )/ R (λ 2 )]+ c 0   (1) [0037] Numerical simulations and in vitro experiments indicate that the total tissue water fraction, f w T , can be estimated with an accuracy of approximately +/−2% over a range of water contents between 50 and 80% using Equation (1), with reflectances R(λ) measured at two wavelengths and the calibration constants c 0 and c 1 chosen empirically. Examples of suitable wavelength pairs are λ 1 =1300 nm, λ 2 =1168 nm, and λ 1 =1230 nm, λ 2 =1168 nm. [0038] The ability to measure changes in the total tissue water content in the ear of a pig using two-wavelength NIR reflectometry was demonstrated experimentally in a study in which a massive hemorrhage was induced in a pig and the lost blood was replaced with lactated Ringer's solution over a period of several hours. Ringer's solution is a well-known solution of salts in boiled and purified water. FIG. 1 shows the total water fraction in the skin of the ear of a pig, measured using Equation (1) with λ 1 =1300 nm and λ 2 =1168 nm. Referring to FIG. 1 , it should be noted that experimental observations of concern to this embodiment commence when the lactated Ringer's solution was infused 120 minutes after the start of the experiment. It should also be noted that the drift in the total water fraction from approximately 77.5% to 75% before the infusion is not related to this infusion experiment, but is related to the base-line hemorrhage portion of the experiment. The results show that the method of the present embodiment correctly reflects the effect of the infusion by showing an increase in total tissue water fraction from approximately 75% to 79% while the infusion is continuing. These data suggest that the disclosed embodiment has a clear value as a monitor of rehydration therapy in a critical care setting. [0039] In another embodiment of the present invention the water fraction, f w is estimated according to Equation (2) below, based on the measurement of reflectances, R(λ) at three wavelengths and the empirically chosen calibration constants c 0 , c 1 and c 2 : f w =c 2 log[ R (λ 1 )/ R (λ 2 )]+ c 1 log[ R (λ 2 )/ R (λ 3 )]+ c 0   (2) [0040] Better absolute accuracy can be attained using Equation (2) which incorporates reflectance measurements at an additional wavelength. The results of in vitro experiments on excised skin indicate that the wavelength triple (λ 1 =1190 nm, λ 2 =1170 nm, λ 3 =1274 mm) yields accurate estimates of total tissue water content based on Equation (2). [0041] In yet another embodiment of the present invention the water fraction, f w is estimated according to Equation (3) below, based on the measurement of reflectances, R(λ) at three wavelengths and the empirically chosen calibration constants c 0 and c 1 : f w = c 1 ⁢ log ⁡ [ R ⁡ ( λ 1 ) / R ⁡ ( λ 2 ) ] log ⁡ [ R ⁡ ( λ 3 ) / R ⁡ ( λ 2 ) ] + c 0 ( 3 ) [0042] Better absolute accuracy can be attained using Equations (3), as is attained using Equations (2), which also incorporates reflectance measurements at an additional wavelength. Numerical simulations as shown in FIG. 2 indicate that total tissue water accuracy better than +/−0.5% can be achieved using Equation (3), with reflectances measured at three closely spaced wavelengths: λ 1 =1710 nm, λ 2 =1730 nm, and λ 3 =1740 nm. Additional numerical simulations indicate that accurate measurement of the lean tissue water content, f w l ,can be accomplished using Equation (3), by combining reflectance measurements at 1125, 1185, and 1250 nm. [0043] An additional embodiment of the present invention is directed towards the measurement of water content as a fraction of fat-free or lean tissue content, f w l . [0044] Preferably, a tissue water monitor provides the clinician with an indication of whether the patient requires more, less, or no water to achieve a normo-hydrated state. Such a measurement may be less universally applicable than clinically desired when it is determined using an instrument that reports fractional water relative to either total body weight or total tissue content, due to the high variability of fat content across the human population. Fat contains very little water, so variations in the fractional fat content of the body lead directly to variations in the fractional water content of the body. When averaged across many patients, gender and age-related differences in fat content, result in systematic variations in water content, a fact that has been well-documented in the literature, as is shown for example in FIG. 7 . Values shown in FIG. 7 are computed from Tables II-III of Cohn et al., J. Lab. Clin. Med. (1985) 105(3), 305-311. [0045] In contrast, when fat is excluded from the calculation, the fractional water content, f w l , in healthy subjects, is consistent across both gender and age, as is shown, for example, in FIG. 7 . This suggests that f w l , can be a more clinically useful measurement than f w for certain conditions. An additional reduction in the subject-to-subject variation in the “normal” level of fractional water content may observed if bone mass is excluded from the calculation, as may be seen in FIG. 8 . This may be due to the fact that the bone content of the body tends to decrease with age (such as by osteoporosis). Due to the specified source-detector separations (e.g., 1-5 mm), wavelength ranges, and algorithms, the measurement of f w l in tissue according to the embodiments of the present invention will be closely related to the whole body water content as a fraction of the fat-free-bone-free body content. [0046] In yet another embodiment of the present invention, tissue water fraction, f w , is estimated according to the following equation, based on the measurement of reflectances, R(λ), at a plurality of wavelengths: f w = [ ∑ n = 1 N ⁢ p n ⁢   ⁢ log ⁢ { R ⁡ ( λ n ) } ] - [ ∑ n = 1 N ⁢ p n ] ⁢   ⁢ log ⁢ { R ⁡ ( λ N + 1 ) } [ ∑ m = 1 M ⁢ q m ⁢   ⁢ log ⁢ { R ⁡ ( λ m ) } ] - [ ∑ m = 1 M ⁢ q m ] ⁢   ⁢ log ⁢ { R ⁡ ( λ M + 1 ) } ( 4 ) where p n and q m are calibration coefficients. [0047] An obstacle to the quantification of tissue analytes is the high subject-to-subject variability of the scattering coefficient of tissue. Determination of the fractional tissue water in accordance with Equation (4) provides similar advantage as that of Equation (3) above, in that scattering variation is automatically cancelled, especially as long as the N+1 wavelengths are chosen from within the same wavelength band (950-1400 nm, 1500-1800 nm, or 2000-2300 nm). An explanation of the manner in which Equation (4) automatically cancels scattering variations is provided below. [0048] Tissue reflectance can be modeled according to a modified form of the Beer-Lambert equation: log ⁢ { R ⁡ ( λ ) } = - l ⁡ ( λ ) ⁢   ⁢ ∑ j = 1 J ⁢ c j ⁢ ɛ j ⁡ ( λ ) - log ⁢ { I 0 ⁡ ( λ ) } ( 5 ) where R is the tissue reflectance, l is the mean pathlength of light at wavelength λ, ε j and c j are the extinction coefficient and concentration of constituent j in the tissue, and log {I 0 (λ)} is a scattering offset term. According to this model, the scattering dependence of tissue reflectance is due to the offset term, log{I 0 (λ)}, and the pathlength variation term, l(λ). Since the scattering coefficient varies slowly with wavelength, by selecting all of the wavelengths from within the same wavelength band, the wavelength dependence of the scattering coefficient can be ignored to a good approximation. Under these conditions, by multiplying the log of the reflectance at wavelength N+1 (or M+1) by the negative of the sum of the coefficients used to multiply the log of the reflectances at the N (or M) other wavelengths, the scattering offset terms are cancelled in both the numerator and denominator of Equation (4). This can be seen, for example, by substituting Equation (5) into the numerator of Equation (4): [ ∑ n = 1 N ⁢ p n ⁢   ⁢ log ⁢ { R ⁡ ( λ n ) } ] - [ ∑ n = 1 N ⁢ p n ] ⁢   ⁢ log ⁢ { R ⁡ ( λ N + 1 ) } = - l ⁢   ⁢ ∑ n = 1 N ⁢ [ p n ⁢   ⁢ ∑ j = 1 J ⁢ c j ⁢ ɛ j ⁡ ( λ n ) ] + l ⁡ [ ∑ n = 1 N ⁢ p n ] ⁢   ⁢ ∑ j = 1 J ⁢ c j ⁢ ɛ j ⁡ ( λ N + 1 ) ( 6 ) [0049] A review of Equation (6) shows that the scattering offset term has been cancelled, but the scattering dependent pathlength variation term, l, remains. When the numerator and denominator of Equation (4) are combined, the pathlength variation term is also cancelled, as shown in Equation (7): f w = - ∑ n = 1 N ⁢ [ p n ⁢ ∑ j = 1 J ⁢ c j ⁢ ɛ j ⁡ ( λ n ) ] + [ ∑ n = 1 N ⁢ p n ] ⁢   ⁢ ∑ j = 1 J ⁢ c j ⁢ ɛ j ⁡ ( λ N + 1 ) - ∑ m = 1 M ⁢ [ q m ⁢ ∑ j = 1 J ⁢ c j ⁢ ɛ j ⁡ ( λ m ) ] + [ ∑ m = 1 M ⁢ q m ] ⁢   ⁢ ∑ j = 1 J ⁢ c j ⁢ ɛ j ⁡ ( λ M + 1 ) ( 7 ) [0050] A review of Equation (7) shows that Equation (7) depends only on the concentrations and extinction coefficients of the constituents of tissue and on the calibration coefficients p n and q m . [0051] In addition to providing for variable scattering compensation, the methods using Equation (4) allow a more general implementation by relaxing some of the constraints that are imposed by the use of Equation (3), above. For example: [0052] (a) In order to provide a certain level of accuracy for measurement of f w , the numerator in Equation (3) may need to be sensitive to changes in water concentration but insensitive to changes in all other tissue constituents. For example, Equation (3) may require that the absorbance of all tissue constituents besides water (e.g. lipid, non-heme protein, hemoglobin) are nearly equal at wavelengths 1 and 2. This constraint is removed in Equation (4), where the coefficients p n are chosen to cancel out absorbance by all tissue constituents other than water. [0053] (b) In order to provide a certain level accuracy for measurement of f w , the denominator in Equation (3) may need to be equally sensitive to concentration changes of all tissue constituents to which the water fraction is to be normalized. In addition, Equation (3) may require that the absorbance be equal at wavelengths 2 and 3 for all tissue constituents to be excluded from the water fraction normalization. This constraint is removed in Equation (4), where the coefficients, q m , can be chosen to cancel the absorbance contribution due to certain constituents, while equalizing the absorbance sensitivity to the remaining tissue constituents. [0054] In the case of measurement of the water fraction in lean tissue, f w l , the coefficients, p n , in the numerator of Equation (4) are chosen to cancel the contribution from all of the major light-absorbing constituents of tissue, except water. Similarly, the coefficients, q m , in the denominator of Equation (4) are chosen to cancel the contribution from all tissue constituents other than water and protein. In addition, the coefficients, q m , are chosen to equalize the sensitivity of the denominator to changes in water and protein on a volume fractional basis. By computing the ratio of these two terms, the result is a fractional volume measurement of water concentration in lean tissue. [0055] In addition, application of Equation (4) to the measurement of fractional water content in total tissue volume, f w T , is accomplished by choosing the coefficients in the denominator of Equation (4), q m , so that all tissue constituents (including lipid) are equalized on a fractional volume basis. [0056] By relaxing some of the constraints imposed by Equation (3), the use of Equation (4) can be expected to produce a more accurate prediction of fractional tissue water content, for the reasons set forth above. Various wavelength combinations may be used based on the criteria disclosed above. In order to select one wavelength combination for use with Equation (4) for the purpose of measuring fractional water content in lean tissue, f w l , extinction coefficients of the major absorbing constituents of tissue (water, non-heme protein, lipid, and hemoglobin) were experimentally measured and various wavelength combinations of these were applied to a numerical model of tissue absorbance. The reproducibility of the algorithms incorporating the most promising of these wavelength combinations were then compared using real tissue data. The real tissue data were collected from 37 different volunteers at a local hospital, with Institutional Review Board (IRB) approval. The sensor measured reflected light from the pad of the finger, with a source-detector spacing of approximately 2.5 mm. The sensor was completely removed from the tissue between each pair of measurements. One such preferred algorithm combines measurements at 4 wavelengths, namely: 1180, 1245, 1275, and 1330 nm. Using this selection of wavelengths, the measurement-to-measurement reproducibility, as shown in FIG. 9 , is 0.37%, indicating high reproducibility of the tissue water measurements using the methods disclosed herein. [0057] In addition to providing a method for measuring tissue water fraction, the method in accordance with Equation (4) above, also has general utility for the fractional quantification of analytes in tissue. In general, by appropriate choice of wavelengths and coefficients, Equation (4) is extendible to the fractional concentration measurement of any tissue constituent or combination of constituents in tissue with respect to any other constituent or combination of constituents. For example, this equation is also applicable for the determination of the fractional hemoglobin content in tissue. [0058] Thus, in one embodiment of the present invention, the fractional volume of total hemoglobin in tissue is determined using Equation (4) by combining reflectance measurements at wavelengths where hemoglobin is strongly absorbing with reflectance measurements where the remaining tissue constituents (such as water, lipid, and non-protein) are strongly absorbing. The coefficients, p n , in the numerator of Equation (4) are chosen to cancel the absorbance contributions from all tissue constituents except total hemoglobin. The coeffients, q m , in the denominator of Equation (4) are chose to equalize the absorbance contributions of all major tissue constituents, on a volume fractional basis. One specific wavelength combination for accomplishing this measurement is 805 nm, 1185 nm, and 1310 nm. At 805 nm the absorbance by the oxy- and deoxyhemoglobin are approximately equal. At 1185 nm, the absorbance of water, non-heme protein, and lipid, are nearly equal on a fractional volume basis. At 1300 nm the tissue absorbance will be dominated by water. [0059] In another embodiment of the present invention, measurement of fractional concentrations of different species of hemoglobin in tissue is performed. In general, the method provides a means of measuring the fractional concentration of hemoglobin in a first set comprised of one or more species of hemoglobin with respect to the concentration of hemoglobin in a second set comprised of one or more hemoglobin species in tissue. The coefficients, p n , in the numerator of Equation (4) are chosen to cancel the absorbance contributions from all tissue constituents except the hemoglobin species included in set 1. The coeffients, q m , in the denominator of Equation (4) are chose to equalize the absorbance contributions from all tissue constituents except the hemoglobin species included in set 2. Sets 1 and 2 are subsets of hemoglobin species that are present in the body tissue or blood. For example, such hemoglobin species include oxyhemoglobin, deoxyhemoglobin, carboxyhemoglobin, methemoglobin, sulfhemoglobin and, so on. And in general, as used herein, other physiological parameters have other subsets of constituents each being capable of absorbing at different wavelengths. In the case where set 1 is comprised of oxyhemoglobin and set 2 is comprised of oxy- and deoxyhemoglobin, a specific wavelength combination for accomplishing the measurement is 735, 760, and 805 nm. [0060] Individuals skilled in the art of near-infrared spectroscopy would recognize that, provided that the aforementioned guidelines are followed, additional terms can be added to Equations (1)-(4) and which may be used to incorporate reflectance measurements made at additional wavelengths and thus improve accuracy further. [0061] An additional embodiment of the disclosed invention provides the ability to quantify shifts of fluid into and out of the bloodstream through a novel application of pulse spectrophotometry. This additional embodiment takes advantage of the observation that pulsations caused by expansion of blood vessels in the skin as the heart beats produce changes in the reflectance at a particular wavelength that are proportional to the difference between the effective absorption of light in the blood and the surrounding interstitial tissues. Numerical simulation indicate that, if wavelengths are chosen at which water absorption is sufficiently strong, the difference between the fractions of water in the blood, f w IV and surrounding tissue, f w EV is proportional to the ratio of the dc-normalized reflectance changes (ΔR/R) measured at two wavelengths, according to Equation (8) below: f w EV - f w IV = c 1 ⁢ ( Δ ⁢   ⁢ R / R ) λ 1 ( Δ ⁢   ⁢ R / R ) λ 2 + c 0 , ( 8 ) where c 0 and c 1 are empirically determined calibration constants. This difference, integrated over time, provides a measure of the quantity of fluid that shifts into and out of the capillaries. FIG. 3 shows the prediction accuracy expected for the wavelength pair λ 1 =1320 nm and λ 2 =1160 nm. [0062] An additional embodiment of the present invention is directed towards the measurement of water balance index, Q, such that: Q = f w IV - f w EV f h IV = a 1 ⁢ ( Δ ⁢   ⁢ R / R ) λ 1 ( Δ ⁢   ⁢ R / R ) λ 2 + a 0 ( 9 ) where f h IV is the fractional volume concentration of hemoglobin in the blood, and a o and a 1 are calibration coefficients. The use of Equation (9) to determine a water balance is equivalent to using Equation (8) above, where f h IV is set equal to 1. However, using Equation (9) provides for a more accurate determination by not neglecting the influence of f h IV on the derived result. The effect of this omission can be understood by allowing total hemoglobin to vary over the normal physiological range and computing the difference between the results provided by Equation (9) when f h IV is fixed or allowed to vary. For example, when calculations were performed with f w EV fixed at 0.65, f w IV varying between 0.75 and 0.80, and f h IV varying between 0.09 and 0.135 or held fixed at 0.112, the resulting error was as large as +/−20%. In situations of extreme blood loss or vascular fluid overload (hypo- or hypervolemia) the error could be larger. [0063] The quantity Q, provided by Equation (9) may be combined with a separate measurement of fractional hemoglobin concentration in blood, f h IV , (such as may be provided by standard clinical measurements of hematocrit or total hemoglobin) in order to provide a measure of the difference between the intravascular and extravascular water content, f h IV -f w EV . Alternatively, the quantity Q, may have clinical utility without further manipulation. For example, by providing a simultaneous measurement of both Q and fractional tissue water (either f w or f w l ), the embodiments of the present invention enable the provision of a clinical indication of changes in both volume and osmolarity of body fluids. Table 1 lists the 6 combinations of volume and osmolarity changes in body fluids that are clinically observed (from Physiology, 2 nd Edition, Linda S. Costanzo, Williams and Wilkins, Baltimore, 1998, pg. 156), and the expected direction and magnitude of the resultant change in fractional volume of water in blood (f w IV ), the fractional volume of water in tissue (f w EV ), the fractional volume of hemoglobin in blood (f h IV ), the numerator of Q (Q n ), the inverse of the denominator of Q (1/Q d ), the combined result (Q n /Q d =Q), and the fractional volume of water in lean tissue, f w l . Taking the first row of Table 1 as an example, the result of isosmotic volume expansion, such as may be brought about by infusion with isotonic saline, would result in an increase in the fraction of water in blood (f w IV ), a small increase in the extravascular water fraction (f w EV ), and a large decrease in the fractional concentration of hemoglobin in the blood (f h IV ). The combined effect of these 3 factors would result in a large increase in Q. A small increase in the fraction of water in the lean tissue, f w l , would also be expected. Notice that when Q and f w l are viewed in combination, they provide unique signatures for each of the 6 types of fluid balance change listed in Table 1. An instrument providing these measurements in a non-invasive and continuous fashion is thus able to provide a powerful tool for the monitoring of tissue water balance. TABLE 1 Expected changes in Q and f w l resulting from changes in body fluid volume and osmolarity Type Example f w IV f w EV f h IV Q n 1/Q d Q f w l Isosmotic volume Isotonic NaCl ↑ ↑ ↓ ↑ ↑ ↑ ↑ expansion Infusion Isosmotic volume Diarrhea ↓ ↓ ↑ ↓ ↓ ↓ ↑ contraction Hyperosmotic High NaCl ↑ ↓ ↓ ↑ ↑ ↑ 0 volume expansion intake Hyperosmotic Sweating, ↓ ↓ ↑ 0 ↓ ↓ ↓ volume contraction Fever Hyposmotic SIADH ↑ ↑ ↓ 0 ↑ ↑ ↑ volume contraction Hyposmotic Adrenal ↓ ↑ ↑ ↓ ↓ ↓ 0 volume contraction Insufficiency [0064] FIGS. 4 and 5 show diagrams of two different versions of an instrument for measuring the amount of water in body tissues. The simplest version of the instrument 400 shown in FIG. 4 is designed for handheld operation and functions as a spot checker. Pressing the spring-loaded probe head 410 against the skin 412 automatically activates the display of percent tissue water 414 . The use of the spring-loaded probe head provides the advantages of automatically activating the display device when needed and turning the device off when not in use, thereby extending device and battery life. Moreover, this unique use of a spring-loaded probe also provides the variable force needed to improve the reliability of measurements. Percent tissue water represents the absolute percentage of water in the skin beneath the probe (typically in the range 0.6-0.9). In one embodiment of the present invention, the force exerted by a spring or hydraulic mechanism (not shown) inside the probe head 410 is minimized, so that the fluid content of the tissue beneath the probe is not perturbed by its presence. In this manner, the tissue water fraction, including both intravascular and extravascular fluid fractions is measured. In another embodiment of the invention, the force exerted by the probe head is sufficient to push out most of the blood in the skin below the probe to allow measurement of only the extravascular fluid fraction. A pressure transducer (not shown) within the probe head 410 measures the compressibility of the skin for deriving an index of the fraction of free (mobile) water. [0065] The more advanced version of the fluid monitor 500 shown in FIG. 5 is designed for use as a critical-care monitor. In addition to providing a continuous display of the volume fraction of water 510 at the site of measurement 512 , it also provides a trend display of the time-averaged difference between the intravascular fluid volume (“IFV”) and extravascular fluid volume (“EFV”) fractions (e.g., IFV-EFV=f w IV −f w EV ) 514 or the quantity Q (as defined above with reference to Equation (9), updated every few seconds. This latter feature would give the physician immediate feedback on the net movement of water into or out of the blood and permit rapid evaluation of the effectiveness of diuretic or rehydration therapy. To measure the IFV-EFV difference or Q, the monitor records blood pulses in a manner similar to a pulse oximeter. Therefore, placement of the probe on the finger or other well-perfused area of the body would be required. In cases in which perfusion is too poor to obtain reliable pulse signals, the IFV-EFV or Q display would be blanked, but the tissue water fraction (f w ) would continue to be displayed. A mechanism for mechanically inducing the pulse is built into the probe to improve the reliability of the measurement of IFV-EFV or Q under weak-pulse conditions. [0066] FIG. 6 . is a block diagram of a handheld device 600 for measuring tissue water fraction, as well as shifts in water between the IFV and EFV compartments, or a measurement of Q, with a pulse inducing mechanism. Using this device 600 , patient places his/her finger 610 in the probe housing. Rotary solenoid 612 acting through linkage 614 and collar 616 induces a mechanical pulse to improve the reliability of the measurement of IFV-EFV or Q. LEDs 618 emit light at selected wavelengths and photodiode 620 measure the transmitted light. Alternately, the photodiode 620 can be placed adjacent to the LEDs to allow for the measurement of the reflectance of the emitted light. Preamplifier 622 magnifies the detected signal for processing by the microprocessor 624 . Microprocessor 624 , using algorithms described above, determines the tissue water fraction (f w ) (such as in the total tissue volume (f w T ), within the lean tissue volume (f w l ), and/or within the IFV (f w IV ) and the EFV (f w EV )), as well as shifts in water between the IFV and EFV (such as IFV-EFV or Q), and prepares this information for display on display device 626 . Microprocessor 624 is also programmed to handle the appropriate timing between the rotary solenoid's operation and the signal acquisition and processing. In one embodiment, a means is provided for the user to input the fractional hemoglobin concentration (f h IV ) or a quantity proportional to f h IV (such as hematocrit or total hemoglobin) in order to convert Q into IFV-EFV. The design of the device and the microprocessor integrates the method and apparatus for reducing the effect of noise on measuring physiological parameters as described in U.S. Pat. No. 5,853,364, assigned to Nellcor Puritan Bennett, Inc., the entire disclosure of which is hereby incorporated herein by reference. Additionally, the design of the device and the microprocessor also integrates the electronic processor as described in U.S. Pat. No. 5,348,004, assigned to Nellcor Incorporated, the entire disclosure of which is hereby incorporated herein by reference. [0067] As will be understood by those skilled in the art, other equivalent or alternative methods for the measurement of the water fraction within tissue (f w ), as well as shifts in water between the intravascular and extravascular compartments, IVF-EVF or Q, according to the embodiments of the present invention can be envisioned without departing from the essential characteristics thereof. For example, the device can be operated in either a handheld or a tabletop mode, and it can be operated intermittently or continuously. Moreover, individuals skilled in the art of near-infrared spectroscopy would recognize that additional terms can be added to the algorithms used herein to incorporate reflectance measurements made at additional wavelengths and thus improve accuracy further. Also, light sources or light emission optics other then LED's including and not limited to incandescent light and narrowband light sources appropriately tuned to the desired wavelengths and associated light detection optics may be placed within the probe housing which is placed near the tissue location or may be positioned within a remote unit; and which deliver light to and receive light from the probe location via optical fibers. Additionally, although the specification describes embodiments functioning in a back-scattering or a reflection mode to make optical measurements of reflectances, other embodiments can be working in a forward-scattering or a transmission mode to make these measurements. These equivalents and alternatives along with obvious changes and modifications are intended to be included within the scope of the present invention. Accordingly, the foregoing disclosure is intended to be illustrative, but not limiting, of the scope of the invention which is set forth in the following claims.

Devices and methods for measuring body fluid-related metric using spectrophotometry that may be used to facilitate diagnosis and therapeutic interventions aimed at restoring body fluid balance. In one embodiment, the present invention provides a device for measuring a body-tissue water content metric as a fraction of the fat-free tissue content of a patient using optical spectrophotometry. The device includes a probe housing configured to be placed near a tissue location which is being monitored; light emission optics connected to the housing and configured to direct radiation at the tissue location; light detection optics connected to the housing and configured to receive radiation from the tissue location; and a processing device configured to process radiation from the light emission optics and the light detection optics to compute the metric where the metric includes a ratio of the water content of a portion of patient's tissue in relation to the lean or fat-free content of a portion of patient's tissue.

TECHNICAL FIELD [0001] The invention pertains to methods of forming material adjacent electrical components and to methods of forming material between conductive electrical components. The invention further pertains to insulating materials formed adjacent or between conductive electrical components. BACKGROUND OF THE INVENTION [0002] A prior art semiconductor wafer fragment 10 is illustrated in FIG. 1. Wafer fragment 10 comprises a substrate 12 and conductive 11 electrical components 14 , 16 and 18 overlying substrate 12 . Conductive electrical components 14 , 16 and 18 may comprise. for example, conductive lines. Such conductive lines may be formed from metal, or conductively-doped polysilicon. Between conductive components 14 , 16 and 18 is formed an insulative material 20 . Material 20 electrically isolates conductive elements 14 , 16 and 18 from one another. Insulative material 20 may comprise materials known to persons of ordinary skill in the art, including, for example, silicon dioxide, silicon nitride, and undoped silicon. Although each of these materials has good insulative properties, the materials disadvantageously have high dielectric constants which can lead to capacitive coupling between proximate conductive elements, such as elements 14 , 16 and 18 . For instance, silicon nitride 2 has a dielectric constant of about 8 and undoped silicon has a dielectric constant of about 11.8. [0003] A prior art method for insulating conductive elements 14 , 16 and 18 from one another, while reducing a dielectric constant of a material between conductive elements 14 , 16 and 18 is illustrated in FIGS. 2 and 3. In referring to FIGS. 2 and 3, similar numbers to those utilized in FIG. 1 will be used, with differences indicated by the suffix “a” or by different numerals. [0004] Referring to FIG. 2, a semiconductor wafer fragment 10 a is illustrated. Fragment 10 a comprises a substrate 12 a , and overlying conductive lines 14 a , 16 a and 18 a . Between lines 14 a . 16 a and 18 a is a carbon layer 22 . Conductive lines 14 a . 16 a and 18 a are inlaid within carbon layer 22 by a damascene method. A thin. gas-permeable, silicon dioxide layer 24 is formed over conductive lines 17 a , 16 a and 18 a , and over carbon layer 22 . [0005] Referring to FIG. 3, carbon layer 22 is vaporized to form voids 26 between conductive elements 14 a , 16 a and 18 a . Voids 26 contain a gas. Gasses advantageously have dielectric constants of about 1. [0006] It would be desirable to develop alternative methods for insulating conductive elements from one another with low-dielectric-constant materials. SUMMARY OF THE INVENTION [0007] The invention encompasses methods of forming insulating materials between conductive elements The invention pertains particularly to methods utilizing low-dielectric-constant materials for insulating conductive elements, and to structures encompassing low-dielectric-constant materials adjacent or between conductive elements. [0008] In one aspect, the invention encompasses a method of forming a material adjacent a conductive electrical component. The method includes providing a mass adjacent the conductive electrical component and partially vaporizing the mass to form a matrix adjacent the conductive electrical component. The matrix can have at least one void within it. [0009] In another aspect, the invention encompasses a method of forming a material adjacent a conductive electrical component which includes providing a mass comprising polyimide or photoresist adjacent the conductive electrical component. The method further includes at least partially vaporizing the mass. [0010] In another aspect, the invention encompasses a method of forming a material between a pair of conductive electrical components. The method includes forming at least one support member between the pair of conductive electrical components. The method further includes providing a mass between the at least one support member and each of the pair of conductive electrical components. Additionally, the method includes vaporizing the mass to a degree effective to form at least one void between the support member and each of the pair of conductive electrical components. [0011] In yet another aspect, the invention encompasses an insulating material adjacent a conductive electrical component. The insulating material comprises a matrix and at least one void within the matrix. [0012] In yet another aspect, the invention encompasses an insulating region between a pair of conductive electrical components. The insulating region comprises a support member between the conductive electrical components, the support member not cent sing a conductive interconnect. The insulating region further comprises at least one void between the support member and each of the pair of conductive electrical components. BRIEF DESCRIPTION OF THE DRAWINGS [0013] Preferred embodiments of the invention are described below with reference to the following accompanying drawings. [0014] [0014]FIG. 1 is a diagrammatic cross-sectional view of a prior art semiconductor wafer fragment. [0015] [0015]FIG. 2 is a diagrammatic cross-sectional view of a semiconductor wafer fragment at a preliminary step of a prior art processing method. [0016] [0016]FIG. 3 is a view of the FIG. 2 wafer fragment at a prior art processing step subsequent to that of FIG. 2. [0017] [0017]FIG. 4 is a diagrammatic cross-sectional view of a semiconductor wafer fragment at a preliminary step of a processing method of the present invention. [0018] [0018]FIG. 5 is a view of the FIG. 4 wafer fragment shown at a processing step subsequent to that of FIG. 4. [0019] [0019]FIG. 6 is a view of the FIG. 4 wafer fragment shown at a step subsequent to that of FIG. 5. [0020] [0020]FIG. 7 is a diagrammatic cross-sectional view of a semiconductor wafer fragment at a preliminary processing step according to second embodiment of the present invention. [0021] [0021]FIG. 8 is a view of the FIG. 7 wafer fragment shown at a step subsequent to that of FIG. 7. [0022] [0022]FIG. 9 is a diagrammatic cross-sectional V of a semiconductor wafer fragment processed according to a third embodiment of the present invention. [0023] [0023]FIG. 10 is a diagrammatic cross-sectional view of a semiconductor wafer fragment at a preliminary step of a processing sequence according to a fourth embodiment of the present invention. [0024] [0024]FIG. 11 is a view of the FIG. 10 wafer fragment shown at a processing step subsequent to that of FIG. 10. [0025] [0025]FIG. 12 is a view of the FIG. 10 wafer fragment shown at a processing step subsequent to that of FIG. 11. [0026] [0026]FIG. 13 is a diagrammatic cross-sectional view of a semiconductor wafer fragment processed according to a fifth embodiment of the present invention. [0027] [0027]FIG. 14 is a diagrammatic cross-sectional view of a semiconductor wafer fragment processed according to a sixth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0028] This disclosure of the invention is submitted in furtherance of the constitutional purposes of the U.S. Patent Laws “to promote the progress of science and useful arts” (Article 1, Section 8). [0029] A first embodiment of the present invention is described with a reference to FIGS. 4 - 6 . In describing the first embodiment, like numerals from the preceding discussion of the prior art are utilized where appropriate, with differences being indicated by the suffix “b” or by different numerals. [0030] Referring to FIG. 4, a semiconductor wafer fragment 10 b is illustrated. Semiconductor wafer fragment 10 b comprises a substrate 12 b , and conductive elements 14 b , 16 b and 18 b overlying substrate 12 b . Conductive elements 14 b , 16 b and 18 b may comprise, for example, conductive lines. Substrate 12 b may comprise, for example, an insulative layer over a semiconductive substrate. [0031] Electrical components 14 b , 16 b and 18 b are horizontally displaced from one another, with electrical components 14 b and 18 b being laterally outwardly displaced from component 16 b . A mass 30 is between electrical components 14 b and 16 b , and between electrical components 16 b and 18 b . Mass 30 is also outwardly adjacent outer conductive elements 14 b and 18 b. [0032] Mass 30 is preferably an insulative material and may comprise, for example, carbon. Alternatively, by way of example only, mass 30 can comprise polyimide or photoresist. In yet other alternative aspects of the invention, mass 30 can comprise a mixture or a material which is substantially non-vaporizable under selected conditions, and a material which is substantially vaporizable under the selected conditions. Accordingly, complete vaporization of the substantially vaporizable material under the selected conditions will only partially vaporize mass 30 . As an example, mass 30 can comprise a mixture of carbon and silicon dioxide. As another example, mass 30 can comprise a mixture of carbon and SiC x . Preferably, if mass 30 comprises SiC x , “x” will be from about 0.2 to about 1.5. More preferably, if mass 30 comprises a mixture of carbon and SiC x , mass 30 will comprise a mixture from about 20% to about 80% carbon, by volume, and from about 80% to 20% SiC x , by volume, wherein “x” is from about 0.2 to about 1.5. [0033] As will be recognized by persons of ordinary skill in the art, the construction of FIG. 4 may be formed by a number of different methods. For instance, conductive elements 14 b , 16 b and 18 b could be formed first, and mass 30 subsequently deposited over and between conductive elements 14 b , 16 b and 18 b . Mass 30 could then be planarized to a level approximately equal with upper surfaces of conductive elements 14 b , 16 b and 18 b. [0034] As another example, mass 30 could be deposited between an adjacent conductive lines 14 b , 16 b and 18 b , without being deposited over conductive lines 14 b , 16 b and 18 b. [0035] In vet another example, mass 30 could first be formed over substrate 12 b , and subsequently conductive elements 14 b , 16 b and 18 b could be formed within mass 30 by a damascene method. Conductive electrical components 14 b , 16 b and 18 b would thereby effectively be formed within an expanse of mass 30 . [0036] If mass 30 comprises carbon, the carbon may be deposited by plasma decomposition of C(n)H(2n) or C(n)H(2n)X(n), wherein “X” is a halogen such as Br, Cl, I, etc. The deposited carbon is preferably about 10,000 Angstroms thick and can be porous. Porosity of a deposited carbon layer can be adjusted by adjusting deposition parameters, such as, plasma power, temperature, pressure, etc. [0037] Referring to FIG. 5, a layer 32 is formed over mass 30 , and over conductive elements 14 b , 16 b and 18 b . Layer 32 preferably comprises a gas permeable insulative material and may comprise, for example, silicon dioxide. Layer 32 will preferably be relatively thin, such as about 500 Angstroms thick. If layer 32 comprises silicon dioxide, the layer may be formed, for example, by sputter deposition. As will be discussed below, mass 30 can be partially or substantially totally vaporized after provision of layer 32 . Preferably, layer 32 and mass 30 comprise materials which permit mass 30 to be partially or substantially totally vaporized under conditions which do not vaporize layer 32 . [0038] Referring to FIG. 6, mass 30 (shown in FIG. 5) is partially vaporized to form a matrix 34 between conductive elements 14 b , 16 b and 18 b . Matrix 34 is also formed outwardly adjacent outer conductive elements 14 b and 18 b . Matrix 31 can alternatively be referred to as a web, skeleton or scaffolding. [0039] The partial vaporization of mass 30 (shown in FIG. 5) can be accomplished by exposing wafer fragment 10 b to an oxidizing ambient at a temperature of from about 200° C. to about 400° C. Appropriate oxidizing ambients include, for example, O 3 , plasma O 3 , H 2 O 2 , plasma H 2 O 2 , combinations of O 3 and H 2 O 2 , and combinations of plasma O 3 and H 2 O 2 . It is thought that the partial vaporization of mass 30 occurs as excited oxygen atoms diffuse through material 32 and volatize material 34 . For instance, if material 34 comprises carbon, the material will be converted into a gas comprising CO 2 and/or CO, which can diffuse out through layer 32 . [0040] Matrix 34 comprises voids 36 . If pores were originally present in layer 30 , such pores can expand as mass 30 is vaporized to form voids 36 . Preferably, matrix 34 comprises at least one void 36 between each pair of conductive elements. Typically, matrix 34 will comprise a plurality of voids 36 between each pair of conductive elements. The 23 voids and partially vaporized material of matrix 34 provide an insulative material between conductive lines 14 b and 16 b , and between conductive lines 16 b and 18 b , which preferably has a decreased dielectric constant relative to mass 30 (shown in FIG. 5). Accordingly, the conversion of mass 30 to partially vaporized matrix 34 can advantageously decrease capacitive coupling between paired conductive elements 14 b and 16 b , and between paired conductive elements 16 b and 18 b . Preferably, matrix 34 has a dielectric constant of less than or equal to about 2. [0041] An advantage of the embodiment discussed above with reference to FIGS. 4 - 6 , relative to the prior art method discussed in the “Background” section, is that matrix 34 provides a skeletal support structure in the embodiment of the present invention. Such skeletal support structure can assist in supporting layer 32 over an expanse between paired conductive elements 14 b and 16 b . and over an expanse between paired conductive elements 16 b and 18 b . Also, matrix 34 can assist in supporting layer 32 outwardly adjacent outer conductive elements 14 b and 18 b . Further, due to the supporting properties of matrix 34 , layer 32 may be formed either before or after partial vaporization of mass 30 (shown in FIG. 5). [0042] A second embodiment of the present invention is described with reference to FIGS. 7 - 8 . In describing the second embodiment, like numerals from the preceding discussion of the first embodiment are utilized, with differences being indicated by the suffix “c” or with different numerals. [0043] Referring to FIG. 7, a semiconductor wafer fragment 10 c is illustrated. Wafer fragment 10 c comprises a substrate 12 c . Conductive electrical components 14 c , 16 c and 18 c overlie substrate 12 c . Electrical components 14 c , 16 c and 18 c are horizontally displaced from one another, with electrical components 14 c and 18 c being outwardly displaced from component 16 c . A mass 30 c is between electrical components 14 c and 16 c , and between electrical components 16 c and 18 c . Mass 30 c is also outwardly adjacent outer conductive elements 14 c and 18 c . Mass 30 c does not comprise carbon, and preferably comprises either polyimide or photoresist. Substrate 12 c may comprise, for example, an insulative material over a semiconductive wafer. Conductive elements 14 c , 16 c and 18 c may comprise, for example, metal lines. [0044] A layer 32 c is formed over mass 30 c , and over conductive elements 14 c , 16 c and 18 c . Layer 32 c preferably comprises an insulative material, and may comprise, for example, silicon dioxide. The structure of FIG. 7 is quite similar to the structure of FIG. 5, and may therefore be formed by methods such as those discussed above regarding FIG. 5, with the exception that mass 30 c will not comprise carbon. [0045] Referring to FIG. 8, mass 30 c (shown in FIG. 7) is substantially totally vaporized to form voids 36 c between conductive elements 14 c , 16 c and 18 c , and outwardly adjacent outer conductive elements 14 c and 18 c . Mass 30 c can be substantially totally vaporized by exposing wafer 10 c to an oxidizing ambient at a temperature of from about 200° C. to about 400° C. The difference between whether a mass, such as mass 30 of FIG. 5, or mass 30 c of FIG. 7, is partially vaporized (as shown in FIG. 6) or substantially totally vaporized (as shown in FIG. 8) can be determined by the time of exposure of a wafer fragment, such as 10 b or 10 c , to an oxidizing ambient at a temperature of from about 200° C. to about 400° C. Such times are readily determinable by persons of ordinary skill in the art. [0046] The second embodiment of the present invention (discussed above with reference to FIGS. 7 and 8) differs from the prior art method of discussed above in the Background section in that the second embodiment utilizes an insulative layer 30 c which does not comprise carbon, such as a layer of photoresist or polyimide. Such use of photoresist or polyimide insulative layers offers distinct advantages over the prior art use of carbon insulative layers. For instance, while carbon is typically applied by vapor deposition techniques. polyimide and photoresist can be applied by spin-on-wafer techniques. Spin-on-wafer techniques enable the polyimide or photoresist to be applied with a relatively planar upper surface. Such planar upper surface can eliminate planarization processes from some applications of the present invention which would otherwise require planarization processes. [0047] Also, spin-on-wafer techniques offer an advantage in that a solvent can be incorporated into a spin-on-wafer applied layer. Such solvent can be vaporized or otherwise removed from the applied layer during vaporization of the applied layer to increase the size or amount of voids formed within the applied layer. The amount of solvent incorporated into a spin-on-wafer applied layer can be controlled by varying the amount and type of solvent utilized during a spin-on-wafer application of a layer. For instance, a first relatively volatile solvent and a second relatively non-volatile solvent could both be utilized during a spin-on-wafer application. The first solvent would largely evaporate from an applied layer during formation of the layer while the second solvent would substantially remain within the applied layer. [0048] [0048]FIG. 9 illustrates a third embodiment of the present invention. In describing the third embodiment, like numerals from the preceding discussion of the second embodiment are utilized, with differences being indicated by the suffix “d” or with different numerals. [0049] Referring to FIG. 9, a wafer fragment 10 d comprises a substrate 12 d and conductive elements 14 d , 16 d and 18 d overlying substrate 12 d . A layer 32 d overlies conductive elements 14 d , 16 d and 18 d . Voids 36 d are formed between conductive elements 14 d , 16 d and 18 d . Voids 36 d can be formed, for example. by methods analogous to those discussed above with reference to FIGS. 7 and 8, or by methods utilizing substantially total vaporization of a carbon-comprising material. [0050] Wafer fragment 10 d further comprises support members 38 formed between conductive elements 14 d and 16 d , and between conductive elements 16 d and 18 d . Support members 38 can advantageously assist in supporting layer 32 d over the voids 35 d between conductive elements 14 d , 16 d , and 18 d . Support members 38 may comprise either insulative material or conductive material, but preferably do not comprise a conductive interconnect. Accordingly, support members 38 are preferably electrically isolated from conductive elements 14 d , 16 d and 18 d , as well as from other conductive structures which may be comprised by an integrated circuit formed on wafer fragment 10 d. [0051] Support members 38 can be formed by methods readily apparent to persons of ordinary skill in the art. An example method comprises forming support members 38 between conductive elements 14 d , 16 d and 18 d and subsequently forming a mass, such as mass 30 of FIG. 5 or mass 30 c of FIG. 7 between the support members and conductive elements. Layer 32 d could be then formed over the mass, over conductive elements 14 d , 16 d and 18 d , and over support members 38 . Next, the mass could be either partially or substantially totally vaporized to leave voids, such as voids 36 d , between support members 38 and conductive elements 14 d , 16 d and 18 d. [0052] An alternative method of forming support members 38 would comprise forming the support members within an expanse of a mass, such as the mass 30 of FIG. 5, or the mass 30 c of FIG. 7, by a damascene method. [0053] It is noted that structure 38 may be utilized with either methods of partial vaporization of insulative materials, such as the method described with reference to FIGS. 4 - 6 , or with methods of substantially total vaporization of insulative materials, such as the method discussed above with reference to FIGS. 7 - 8 . [0054] A fourth embodiment of the present invention is described with reference to FIGS. 10 - 12 . In describing the fourth embodiment, like numerals from the preceding discussion of the first embodiment are utilized where appropriate, with differences being indicated with the suffix “e” or with different numerals. [0055] Referring to FIG. 10, a semiconductor wafer fragment 10 e is illustrated. Wafer fragment 10 e comprises a substrate 12 e and conductive elements 14 e , 16 e , 18 e and 40 overlying substrate 12 e . A mass 30 e is formed over conductive elements 14 e , 16 e , 18 e and 40 , as well as between the conductive elements. Mass 30 e preferably comprises an insulative material, and can comprise materials such as those discussed above regarding mass 30 (shown in FIG. 4). Mass 30 e extends entirely from conductive element 14 e to conductive element 16 e , entirely from conductive element 16 e to conductive element 18 e , and entirely from conductive element 18 e to conductive element 40 . [0056] Referring to FIG. 11, mass 30 e is anisotropically etched to remove mass 30 e from over conductive elements 14 e , 16 e , 18 e and 40 , and to remove mass 30 e from between conductive elements 18 e and 40 . The anisotropic etching forms spacers 42 from mass 30 e adjacent conductive element 40 and adjacent conductive elements 14 e and 18 e. [0057] After the anisotropic, etching mass 30 e extends entirely from conductive element 14 e to conductive element 16 e and entirely from conductive element 16 e to conductive element 18 e , but no longer extends entirely from conductive element 18 e to conductive element 40 . [0058] As will be recognized by persons of ordinary skill in the art, methods for anisotropically etching mass 30 e will vary depending on the chemical constituency of mass 30 e . Such methods will be readily recognized by persons of ordinary skill in the art. An example method for anisotropically mass 30 e when mass 30 e comprises carbon is a plasma etch utilizing O 2 . [0059] A layer 32 e is formed over spacers 42 , over mass 30 e , and over conductive elements 14 e , 16 e , 18 e and 40 . Layer 32 e preferably comprises a material porous to gas diffusion, such as a silicon dioxide layer having a thickness of about 500 Angstroms or less. [0060] Referring to FIG. 12, mass 30 e (shown in FIG. 11) is substantially totally vaporized to form voids 36 e . After such substantially total vaporization of mass 30 e , spacers 42 comprise an insulative space. Methods for substantially totally vaporizing mass 30 e can include methods discussed above with reference to FIGS. 8 and 9. [0061] A fifth embodiment of the present invention is described with reference to FIG. 13. In describing the fifth embodiment, like numerals from the preceding discussion of the fourth embodiment are utilized where appropriate, with differences being indicated by the suffix “f” or by different numerals. [0062] Referring to FIG. 13, a wafer fragment 10 f is illustrated. Wafer fragment 10 f comprises a substrate 12 f , and conductive electrical components 14 f , 16 f , 18 f and 40 f overlying substrate 12 f . An insulative material 32 f overlies components 14 f , 16 f , 18 f , 40 f , and substrate 12 f . Wafer fragment 10 f is similar to the wafer fragment 10 e of FIG. 12, and may be formed by similar methods. Wafer fragment 10 f differs from the wafer fragment 10 e of FIG. 12 in that wafer fragment 10 f comprises a matrix 34 f of partially vaporized material. Matrix 34 f can be formed from the mass 30 e of FIG. 11 utilizing methods discussed above with reference to FIG. 6. Matrix 34 f comprises voids 36 f. [0063] Wafer fragment 10 f further comprises spacers 42 f adjacent conductive elements 14 f , 18 f and 40 f , with spacers 42 f comprising matrix 34 f and at least one void 36 f. [0064] It is noted that in forming the fifth embodiment of FIG. 13, material 32 f may be formed either before or after formation of matrix 34 f. [0065] A sixth embodiment of the present invention is described with reference to FIG. 14. In describing the sixth embodiment, like numerals from the preceding discussion of the first five embodiments are utilized where appropriate, with differences being indicated by the suffix “g” or , 7 by different numerals. [0066] Referring to FIG. 14, a wafer fragment 10 g is illustrated. Wafer fragment 10 g comprises a substrate 12 g and conductive elements 50 , 52 , 54 , 56 , 58 , 60 , 62 and 64 . Unlike the first five embodiments, the sixth embodiment of FIG. 14 comprises conductive elements which are vertically displaced from one another, for example, elements 50 , 52 and 54 , as well as conductive elements which are horizontally displaced from each other, for example, conductive elements 54 , 56 and 58 . Over conductive elements 52 , 54 , 56 , 58 , 60 , 62 and 64 is a gas permeable insulative layer 32 g. [0067] Wafer fragment 10 g further comprises voids 36 g adjacent and between conductive elements 50 , 52 , 54 , 56 , 58 . 60 , 62 and 64 . Voids 36 g may be formed utilizing the methods discussed above regarding the first five embodiments of the invention. For example, voids 36 g may be formed by providing a mass, analogous to mass 30 c of FIG. 7, adjacent and between conductive elements 50 , 52 , 54 , 56 , 58 , 60 , 62 and 64 , and subsequently substantially totally vaporizing the mass to form voids 36 g . Alternatively, voids 36 g could be formed within a matrix (not shown) analogous to matrix 34 of FIG. 6 utilizing methods such as those discussed above with reference to FIGS. 6 and 13. For instance, a mass analogous to mass 30 of FIG. 5 may be formed adjacent and between conductive elements 50 , 52 , 54 , 56 , 58 , 60 , 62 and 64 and subsequently partially vaporized to form a matrix adjacent and between the conductive elements. [0068] Wafer fragment 10 g further comprises support members 70 , 72 , 74 , 76 and 78 . Support members 70 , 72 , 74 , 76 and 78 may be formed by methods analogous to the methods discussed above for forming support member 38 with reference to FIG. 9. Support members 70 , 72 , 74 , 76 and 78 preferably comprise sizes and shapes analogous to conductive elements formed at a common elevational level with the support members. Accordingly, support members 70 preferably comprise sizes and shapes analogous to that of conductive element 50 ; support members 72 preferably comprise sizes and shapes analogous to that of conductive element 52 ; support members 74 preferably comprise sizes and shapes analogous to those of conductive elements 54 , 56 and 58 ; support members 76 preferably comprise sizes and shapes similar to that of conductive element 60 ; and support members 78 preferably comprise sizes and shapes similar to those of conductive elements 62 and 64 . Such advantageous similarity of the sizes and shapes of support members with sizes and shapes of conductive elements at similar elevational levels to the support members can advantageously assist in maintaining a substantially planar upper layer 32 g. [0069] In compliance with the statute, the invention has been described in language more or less specific as to structural and methodical features. It is to be understood, however, that the invention is not limited to the specific features shown and described, since the means herein disclosed comprise preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted in accordance with the doctrine of equivalents.

The invention encompasses methods of forming insulating materials between conductive elements. In one aspect, the invention includes a method of forming a material adjacent a conductive electrical component comprising: a) partially vaporizing a mass to form a matrix adjacent the conductive electrical component, the matrix having at least one void within it. In another aspect, the invention includes a method of forming a material between a pair of conductive electrical components comprising the following steps: a) forming a pair of conductive electrical components within a mass and separated by an expanse of the mass; b) forming at least one support member within the expanse of the mass, the support member not comprising a conductive interconnect; and c) vaporizing the expanse of the mass to a degree effective to form at least one void between the support member and each of the pair of conductive electrical components. In another aspect, the invention includes an insulating material adjacent a conductive electrical component, the insulating material comprising a matrix and at least one void within the matrix. In another aspect, the invention includes an insulating region between a pair of conductive electrical components comprising: a) a support member between the conductive electrical components, the support member not comprising a conductive interconnect; and b) at least one void between the support member and each of the pair of conductive electrical components.

TECHNICAL FIELD [0001] The present invention relates to a dripper for drip irrigation (hereinafter also referred to as an “dripper”) and a drip irrigation apparatus including the dripper, and particularly to a dripper and a drip irrigation apparatus including the dripper which are suitable for growing plants. BACKGROUND ART [0002] Conventionally, drip irrigation systems have been employed to supply water or irrigation liquid such as liquid fertilizer to the plants to be grown on the soil in the agricultural land, plantation and the like. [0003] Such a drip irrigation system comprises for example a channel terminal and an elongated drip watering tube connected to the channel terminal, wherein the channel terminal comprises a filter, a fertigation apparatus (a chemigation apparatus if necessary), a back flow prevention apparatus, a main pipe, and the like connected in sequence on the downstream side of a pump that brings up water from a water source. The drip watering tube is laid on the soil on which plants may be grown. [0004] The drip watering tube has a plurality of ejection ports provided to an elongated tube main body at a predetermined interval between the adjacent ports along the longitudinal direction of the tube main body. The irrigation liquid in the tube main body is ejected at a predetermined ejection amount per unit time (or ejection speed) from the ejection ports. Thus, the irrigation liquid is slowly supplied to the soil outside of the drip watering tube (that is, drip irrigation is performed). [0005] The drip watering tube can save water and fertilizer. Further, the drip watering tube can supply water at a moderate supply speed, and oxygen for plant roots can be ensured in the soil. Accordingly, plants can be favorably managed for growing. [0006] In the above drip watering tube, a plurality of drippers, which correspond to the respective ejection ports, for controlling the amount of the irrigation liquid to be ejected from the respective ejection ports per unit time are provided. [0007] The dripper is configured, for example, such that water flowing in the tube main body flows into the dripper through an inlet of the dripper and flows through a pressure reduction channel, which is called labyrinth, in the dripper to reduce the pressure of the water, and is ejected from the ejection port communicated with the pressure reduction channel on the downstream side thereof. [0008] Further, there are known some conventional drippers provided with a so-called differential pressure control mechanism (pressure correction function). Such conventional drippers have, for example, a three-component structure in which an elastic film (for example, silicone rubber) such as a diaphragm is sandwiched by an inflow side member and an ejection side member, as disclosed in PTL 1. [0009] The dripper disclosed in PTL 1 controls the opening/closing of the entrance port of the dripper and the flow rate of water from the exit port of the dripper, by the movement of the diaphragm (film) in accordance with a water pressure outside of the dripper (in-pipe water pressure). [0010] Specifically, in the dripper disclosed in PTL 1, when the in-pipe water pressure outside of the dripper is increased to a certain level, the diaphragm that is originally so disposed as to shield the entrance is deflected by the in-pipe water pressure toward the outlet. Due to the deformation of the diaphragm, the entrance is opened. When the in-pipe water pressure is further increased, the amount of the deflection of the diaphragm toward the outlet is increased. In association with the deformation of the diaphragm, the sectional size of the channel at the outlet is reduced, and thus the ejection amount of water is regulated. [0011] As disclosed also in paragraph [0004] of PTL 1, the dripper disclosed in PTL 1 is designed such that the ejection speed from the dripper has substantially no relation with the fluctuation in pressure of the supplied liquid for irrigation to the dripper. [0012] Therefore, PTL 1 discloses that the disclosed dripper is favorable for limiting variation in the ejection amount of the irrigation liquid between the drippers disposed on the upstream side (high pressure side) and on the downstream side (low pressure side) in the tube main body, to thereby uniformize the growing of plants over the entire soil. CITATION LIST Patent Literature [0000] PTL 1 Japanese Patent Application Laid-Open No. 2010-46094 SUMMARY OF INVENTION Technical Problem [0015] However, the dripper disclosed in PTL 1 has the following four problems. (First Problem) [0016] The dripper disclosed in PTL 1 has a configuration of sandwiching the diaphragm (film) between other two members. Therefore, an increase in the size of the dripper (in particular, increase in the size in the height direction) is required. Accordingly, the area occupancy of the dripper in the tube main body with respect to the section of the channel becomes naturally larger. [0017] Thus, in the tube main body, the dripper on the upstream side serves as a large hindrance laid on the channel, and hinders the flow of the irrigation liquid that passes through the dripper on the upstream side to be supplied to the dripper on the downstream side. Therefore, the pressure drop in the tube main body is undesirably increased. [0018] Therefore, the dripper disclosed in PTL 1 may require a high pressure pump for long-distance watering utilizing a considerably long drip watering tube, and the ejection amount may also be unstable. (Second Problem) [0019] In addition, the dripper disclosed in PTL 1 may have a problem of an error in the operations of the diaphragm that should control the opening/closing of the entrance port (flow rate of the irrigation liquid) when the three components are assembled together with low precision, causing the flow control of the irrigation liquid to be unstable. (Third Problem) [0020] Further, the dripper disclosed in PTL 1 may have a problem of increased material costs when silicone rubber is used for the diaphragm. (Fourth Problem) [0021] Furthermore, the dripper disclosed in PTL 1 requires that the above three components should be precisely assembled after the three components are separately manufactured, thus making it difficult to enhance manufacturing efficiency. [0022] The present invention has been achieved taking into consideration the above-mentioned problems. An object of the present invention is to provide a dripper and a drip irrigation apparatus including the dripper which can properly perform a long-distance irrigation even when the liquid pressure of irrigation liquid is low, can stabilize the inflow control of the irrigation liquid, and can achieve cost reduction and enhancement in manufacturing efficiency. Solution to Problem [0023] To achieve the above-mentioned object, the present invention provides the following dripper and drip irrigation apparatus. [0000] [1] A dripper for controlling an amount of irrigation liquid ejected from an ejection port extending through a pipe wall of a flow pipe through which the irrigation liquid flows, the dripper configured to be disposed at a position corresponding to the ejection port on an inner peripheral surface of the flow pipe, the dripper including: a substrate including a resin material, to be joined to the inner peripheral surface of the flow pipe, and including a channel part for composing a channel in the dripper, wherein the channel part includes an inflow part that introduces the irrigation liquid in the flow pipe into the dripper, and satisfies one or both of the following items (A) and (B): (A) the inflow part being an inflow control part that controls the inflow of the irrigation liquid based on a set value of a liquid pressure of the irrigation liquid in the flow pipe, the inflow control part having a plate-like body to be exposed to the irrigation liquid in the flow pipe and a first slit formed in the plate-like body, for introducing the irrigation liquid in the flow pipe thereinto, the first slit being formed so as to have an opening width of zero when the plate-like body is not exposed to the irrigation liquid having a liquid pressure equal to or more than the set value, and the plate-like body maintaining the opening width of the first slit at zero without deforming the first slit toward the inner peripheral surface side of the flow pipe so as to inhibit the inflow of the irrigation liquid through the first slit when the liquid pressure is less than the set value, and expanding the first slit such that the opening width of the first slit is more than zero by deforming the first slit toward the inner peripheral surface side of the flow pipe so as to allow the inflow of the irrigation liquid through the first slit when the liquid pressure is equal to or more than the set value; and (B) the channel part further including a flow rate control part formed at a position on a downstream side of the inflow part so as to face the inner peripheral surface of the flow pipe for controlling a flow rate of the irrigation liquid flowing from the inflow part to the ejection port, the flow rate control part having a plate-shaped valve element to be exposed to the introduced irrigation liquid and a second slit being formed in the valve element, for allowing the introduced irrigation liquid to flow toward the ejection port side, the second slit being formed so as to have a predetermined opening width when the valve element does not receive a liquid pressure equal to or more than a predetermined value, and the valve element being deformed toward the inner peripheral surface side from a side of the flow pipe opposite to the inner peripheral surface depending on the liquid pressure to decrease the opening width of the second slit with respect to the predetermined opening width as the liquid pressure is increased. [2] The dripper according to [1], wherein the first slit is formed radially to divide the plate-like body into a plurality of segments. [3] The dripper according to [2], wherein the plate-like body is formed so as to be protruded toward the inner peripheral surface side of the flow pipe. [4] The dripper according to [3], wherein the plate-like body is formed such that a center portion of the plate-like body is protruded the most, and the first slit is formed radially around the center portion. [5] The dripper according to [4], wherein the plate-like body is formed in a domed shape. [6] The dripper according to [1], wherein the valve element is formed so as to be protruded toward a side of the flow pipe opposite to the inner peripheral surface, and the second slit is formed radially to divide the valve element into a plurality of valve segments. [7] The dripper according to [6], wherein the valve element is formed such that a center portion of the valve element is protruded the most, and the second slit is formed radially around the center portion. [8] The dripper according to [7], wherein the valve element is formed in a domed shape. [9] The dripper according to any one of [1] to [8], wherein the flow rate control part is disposed at a position offset in a direction orthogonal to a thickness direction of the substrate with respect to the inflow control part. [10] The dripper according to any one of [1] to [9], wherein the channel part further includes a guide channel part for composing, together with the inner peripheral surface of the flow pipe, a guide channel for guiding the introduced irrigation liquid toward the flow rate control part side, and a hollow part that is formed at a position on a downstream side of the guide channel part and on an upstream side of the flow rate control part and allows communication between the guide channel part and the second slit. [11] The dripper according to any one of [1] to [10], wherein the channel part further includes a pressure reduction channel part for composing, together with the inner peripheral surface of the flow pipe, a pressure reduction channel that allows the irrigation liquid having passed through the flow rate control part or the inflow control part to flow toward the ejection port while reducing the pressure of the irrigation liquid. [12] A drip irrigation apparatus including a flow pipe through which irrigation liquid flows, and the dripper according to any one of [1] to [11] for controlling an amount of the irrigation liquid ejected from an ejection port extending through a pipe wall of the flow pipe, the dripper being disposed at a position corresponding to the ejection port on an inner peripheral surface of the flow pipe. Advantageous Effects of Invention [0024] According to the present invention, even when the liquid pressure of irrigation liquid is low, long-distance watering can be properly performed, and the inflow control of the irrigation liquid can be stabilized. Further, cost reduction and enhancement in manufacturing efficiency can be achieved. [0025] With the invention according to [1], the channel part for composing the channel, of the dripper, including one or both of the inflow control part and the flow rate control part can be integrally formed with the substrate comprising a resin material. Therefore, the dripper can be precisely manufactured at lower cost and at fewer processes and in a smaller size (in particular, reduced thickness (lower height)). As a result, it is possible to achieve cost reduction for the dripper due to reduction in manufacturing cost and enhancement in manufacturing efficiency for the dripper without a high-precision assembly process being required. [0026] In a case where the above inflow part is the inflow control part, even when the liquid pressure (in other words, flow pressure) of the irrigation liquid is low, long-distance watering can be properly performed, and in addition the inflow control and thus the ejection control of the irrigation liquid can be stabilized. When the channel part includes the inflow part and the above flow rate control part, a dripper excellent in the control of the ejecting amount can be provided, thus enabling the ejecting amount of the irrigation liquid to be stabilized. When the channel part includes both the inflow control part and the flow rate control part, the flow rate of the irrigation liquid toward the ejection port can be limited by the flow rate control part, not only in the case of using the dripper under low liquid pressure but also in the case of using the dripper under high liquid pressure, and thus the ejection amount of the irrigation liquid can be properly controlled. [0027] With the invention according to [2], a plurality of segments are deformed toward the inner peripheral surface side of the flow pipe and radially relative to the center of the first slit (outwardly in the radial direction), and in accordance with this deformation the opening width of the first slit is increased. Therefore, it is possible to form the inflow control part in a simple shape suitable to expand the first slit depending on the liquid pressure of the irrigation liquid, thus enabling the inflow control to be further suitable and the costs to be further reduced. [0028] With the invention according to [3], the contact area between each segment and the irrigation liquid is increased, thereby increasing force in a direction to expand the first slit acting on each segment when each segment recieves the liquid pressure. Therefore, even when the liquid pressure of the irrigation liquid is low, each segment can be further surely deformed to allow the first slit to be properly expanded. [0029] With the invention according to [4], a suitable configuration can be selected for aligning the deforming movements of the valve segments by equalizing their size. Therefore, it becomes possible to further simplify the inflow control and further reduce the costs. [0030] With the invention according to [5], the plate-like body can be formed into a further simpler shape. Therefore, it becomes possible to further reduce the costs. [0031] With the invention according to [6], a plurality of valve segments are deformed toward the center of the radial slit while the height of the protrusion toward the side of the flow pipe opposite to the inner peripheral surface is reduced by the liquid pressure, thereby decreasing the opening width of the second slit. Therefore, the flow rate control part can be formed into a simple shape suitable to decrease the opening width of the second slit depending on the liquid pressure of the irrigation liquid, thus enabling the inflow control to be further suitable and the costs to be further reduced. [0032] With the invention according to [7], a suitable configuration can be selected for aligning the deforming movements of the valve segments by equalizing their size. Therefore, it becomes possible to further simplify the inflow control and further reduce the costs. [0033] With the invention according to [8], the valve element can be formed into a further simpler shape. Therefore, it becomes possible to further reduce the costs. [0034] With the invention according to [9], a further reduced thickness can be achieved. Therefore, it becomes possible to allow long-distance watering under low liquid pressure to be further suitable. [0035] With the invention according to [10], even when the flow rate control part is formed at a position offset in a direction orthogonal to the thickness direction from the inflow control part for the purpose of reduced thickness, a part of the channel from the inflow part (inflow control part) to the flow rate control part can be properly formed with a guide channel part and a hollow part formed in the substrate. [0036] With the invention according to [11], it becomes possible to allow the ejection speed to be further suitable by reducing the pressure of the irrigation liquid. [0037] With the invention according to [12], even when the liquid pressure of the irrigation liquid is low, long-distance watering can be properly performed. In addition, the flow control and thus the ejection control (ejection amount) of the irrigation liquid can be stabilized. Further, it is possible to provide a drip irrigation apparatus capable of achieving cost reduction due to the reduction in manufacturing cost and enhancement in manufacturing efficiency without a high-precision assembly process being required. BRIEF DESCRIPTION OF DRAWINGS [0038] FIG. 1 is a transparent perspective birds-eye view of a dripper according to an embodiment of the present invention; [0039] FIG. 2 is a perspective birds-eye view of a substrate for the dripper; [0040] FIG. 3 is a plan view of the substrate; [0041] FIG. 4 is a bottom view of the substrate; [0042] FIG. 5 is a front view of the substrate; [0043] FIG. 6 is a right side view of the substrate; [0044] FIG. 7 is a sectional view of the substrate taken along line A-A in FIG. 3 ; [0045] FIG. 8 is a sectional view of the substrate taken along line B-B in FIG. 3 ; [0046] FIG. 9 is a sectional view of the substrate taken along line C-C in FIG. 3 ; [0047] FIG. 10 is a sectional view schematically illustrating a drip irrigation apparatus according to an embodiment of the present invention; [0048] FIG. 11A is an enlarged perspective birds-eye view illustrating an inflow control part in the present embodiment, and FIG. 11B is an enlarged perspective upward view illustrating the inflow control part; [0049] FIG. 12A is a sectional view schematically illustrating the state in which the inflow control part is closed, and FIG. 12B is a sectional view schematically illustrating the state in which the inflow control part is opened; [0050] FIG. 13A is an enlarged perspective birds-eye view illustrating a flow rate control part in the present embodiment, and FIG. 13B is an enlarged perspective upward view illustrating the flow rate control part; and [0051] FIG. 14A is a sectional view schematically illustrating the flow rate control part in a full-open state, FIG. 14B is a sectional view schematically illustrating the flow rate control part in a semi-open state, and FIG. 14C is a sectional view schematically illustrating the flow rate control part in a full-close state. DESCRIPTION OF EMBODIMENTS [0052] In the following, a dripper according to the present invention and a drip irrigation apparatus including the dripper will be described with reference to FIGS. 1 to 14 . [0053] FIG. 1 is a transparent perspective birds-eye view illustrating dripper 1 of the present embodiment. FIG. 2 is a perspective bird's-eye view of substrate 11 in dripper 1 . FIG. 3 is a plan view of substrate 11 in dripper 1 . FIG. 4 is a bottom view of substrate 11 in dripper 1 . FIG. 5 is a front view of substrate 11 in dripper 1 . FIG. 6 is a right side view of substrate 11 in dripper 1 . FIG. 7 is a sectional view of substrate 11 in dripper 1 , taken along line A-A in FIG. 3 . FIG. 8 is a sectional view of substrate 11 in dripper 1 , taken along line B-B in FIG. 3 . FIG. 9 is a sectional view of dripper 1 taken along line C-C in FIG. 3 . FIG. 10 is a schematic sectional view illustrating drip watering tube 2 as the drip irrigation apparatus in the present embodiment. [0054] As illustrated in FIG. 10 , drip watering tube 2 includes elongated tube main body 3 serving as a flow pipe through which an irrigation liquid flows, and dripper 1 disposed in tube main body 3 . [0055] In addition, as illustrated in FIG. 10 , dripper 1 is disposed on inner peripheral surface 31 of tube main body 3 at a position corresponding to ejection port 33 for ejecting the irrigation liquid, in such a manner as to cover ejection port 33 . Ejection port 33 opens through inner peripheral surface 31 and outer peripheral surface 32 , and extends through the pipe wall of tube main body 3 . Dripper 1 is configured to control the ejection amount per unit time of the irrigation liquid from the corresponding ejection port 33 . [0056] It is noted that, while FIG. 10 illustrates one dripper 1 and one ejection port 33 for convenience, a plurality of drippers 1 and a plurality of ejection ports 33 are actually disposed along the longitudinal direction of tube main body 3 at a predetermined interval between the adjacent ports. [0057] In addition, in FIG. 10 , the right and left sides of the channel in tube main body 3 correspond to the upstream side and the downstream side, respectively. [0058] Further, in the present embodiment, dripper 1 is integrally formed by resin molding using a metal mold. Examples of the resin material used for the resin molding include inexpensive materials such as polypropylene. The molding method may be injection molding. [0059] <Outline of Substrate> [0060] As illustrated in FIGS. 1 to 10 , dripper (dripper main body) 1 has substrate 11 made of a resin material. A channel part for providing a channel for dripper 1 is formed in substrate 11 . The rough external shape of substrate 11 is composed of the respective planar surfaces of bottom end surface 11 a , top surface 11 b at the side opposite to bottom end surface 11 a , left side surface 11 c , right side surface 11 d , front side surface 11 e , and rear side surface 11 f . The vertical and lateral positional relationship among the surfaces is as indicated by cross arrow in FIG. 3 . As illustrated in FIGS. 1 to 10 , top surface 11 b and bottom end surface 11 a are in parallel to each other, left side surface 11 c and right side surface 11 d are in parallel to each other, and front side surface 11 e and rear side surface 11 f are in parallel to each other. In addition, top surface 11 b and bottom end surface 11 a are perpendicular to left side surface 11 c , right side surface 11 d , front side surface 11 e , and rear side surface 11 f . Further, top surface 11 b and bottom end surface 11 a are elongated in the left-right direction. [0061] Substrate 11 is joined to inner peripheral surface 31 of tube main body 3 through bottom end surface 11 a . When tube main body 3 is formed by extrusion molding using a resin material (such as polyethylene) having a melting point equal to or lower than that of the material for dripper 1 (resin material), the above-mentioned joining may be performed by curing tube main body 3 , with ready-made dripper 1 being disposed on inner peripheral surface 31 of tube main body 3 to be cured. [0062] <Specific Configuration of Inflow Control Part> [0063] As illustrated in FIGS. 3 , 7 and 9 , dripper 1 has, at the right end portion of top surface 11 b , inflow control part 111 , which is a part of the channel part of substrate 11 , as an inflow part that introduces the irrigation liquid in tube main body 3 into (into the channel of) dripper 1 . Inflow control part 111 is configured to control the inflow of the irrigation liquid, at the lower limit value of the liquid pressure of the irrigation liquid to be introduced, i.e., the liquid pressure outside of the channel of dripper 1 , or the pressure of the liquid in tube main body 3 (hereinafter, also referred to as “external liquid pressure”). [0064] Specifically, as illustrated in FIG. 11A , inflow control part 111 has plate-like body 1111 to receive the external liquid pressure, and first slit 1112 formed in plate-like body 1111 , for introducing the irrigation liquid in tube main body 3 . [0065] As illustrated in FIG. 11A , plate-like body 1111 is formed into the shape of a thin dome. Plate-like body 1111 is disposed in a cavity formed of cylindrical first elevation surface 11 g that generates an elevation difference from top surface 11 b , in such a manner that the center portion of plate-like body 1111 is protruded the most toward inner peripheral surface 31 side of tube main body 3 (downwardly). As illustrated in FIG. 11A , first slit 1112 is formed radially (in FIG. 11A , in a cross-shaped manner) and concentrically with plate-like body 1111 . Plate-like body 1111 is equally divided into a plurality of (in FIG. 11A , four) segments 1111 a by first slit 1112 . [0066] As illustrated in FIG. 11A , first slit 1112 is formed such that the opening width W 1 is zero when plate-like body 1111 is not exposed to the irrigation liquid having an external liquid pressure equal to or more than the lower limit value in tube main body 3 . The lower limit value is a set lower limit value of the above external liquid pressure. The opening width W 1 is a width in a direction orthogonal to the longitudinal direction of the opening given by first slit 1112 . Inflow control part 111 may be configured by forming first slit 1112 as a cut line not having a substantial gap in plate-like body 1111 . [0067] Further, as illustrated in FIG. 11A , plate-like body 1111 is configured such that the opening width W 1 of first slit 1112 is maintained at zero when the external liquid pressure is less than the set lower limit value. In inflow control part 111 in such closed state, the rigidity of plate-like body 1111 surpasses the external liquid pressure, and thus elastic deformation of plate-like body 1111 toward inner peripheral surface 31 side of tube main body 3 does not occur, to thereby maintain the closed inflow control part 111 . In this case, the inflow of the irrigation liquid through first slit 1112 is inhibited. It is noted that the lower limit value may be 0.005 MPa, for example. [0068] When the external liquid pressure is equal to or more than the above-mentioned lower limit value, plate-like body 1111 undergoes elastic deformation toward inner peripheral surface 31 side of tube main body 3 after yielding to the external liquid pressure. As illustrated in FIG. 11B , that elastic deformation allows plate-like body 1111 to be expanded such that the opening width W 1 of first slit 1112 is more than zero. Thus, inflow control part 111 allows the inflow of the irrigation liquid through first slit 1112 . [0069] FIGS. 12A and 12B illustrate the simulation results of the movement of inflow control part 111 made of polypropylene having a thickness of 0.2 mm, as a specific example of such movement of inflow control part 111 . [0070] When the external liquid pressure is less than 0.005 MPa as the lower limit value, as illustrated in FIG. 12A , the opening width W 1 of first slit 1112 is maintained at zero, so that the inflow of the irrigation liquid into dripper 1 is inhibited. When the external liquid pressure is equal to or more than 0.005 MPa, as illustrated in FIG. 12B , the opening width W 1 is more than zero, so that the inflow of the irrigation liquid into dripper 1 is allowed. [0071] <Specific Configuration of Inflow Control Part> [0072] As illustrated in FIGS. 4 , 9 and 10 , dripper 1 has flow rate control part 112 as a part of the channel part of substrate 11 . Flow rate control part 112 is disposed at left end portion of bottom end surface 11 a , being a position on the downstream side of inflow control part 111 (in other words, a position offset in a direction orthogonal to the thickness direction of substrate 11 with respect to inflow control part 111 ). Flow rate control part 112 is formed so as to face inner peripheral surface 31 of tube main body 3 . That is, flow rate control part 112 is disposed at a position, in substrate 11 , opposed to inner peripheral surface 31 of tube main body 3 . Flow rate control part 112 is configured to control the flow rate of the irrigation liquid (hereinafter, also referred to as “inflow liquid”) that flows into the channel in dripper 1 from inflow control part 111 and flows toward ejection port 33 . [0073] Specifically, as illustrated in FIG. 13A , flow rate control part 112 has plate-shaped valve element 1121 to receive the pressure of the inflow liquid (hereinafter, also referred to as “internal liquid pressure”), and second slit 1122 formed in valve element 1121 , for allowing the inflow liquid to flow toward ejection port 33 side. [0074] As illustrated in FIG. 13A , valve element 1121 is formed into the shape of a thin dome. Valve element 1121 is disposed in a cavity formed of cylindrical second elevation surface 11 h (see FIG. 9 ) that generates an elevation difference from bottom end surface 11 a , in such a manner that the center portion of valve element 1121 is protruded the most toward the side of tube main body 3 opposite to inner peripheral surface 31 (i.e., upwardly protruded). As illustrated in FIG. 13A , second slit 1122 is formed radially (in FIG. 13A , in a cross-shaped manner) around the center portion of valve element 1121 . Valve element 1121 is equally divided into a plurality of (in FIG. 13A , four) valve segments 1121 a by second slit 1122 . [0075] As illustrated in FIG. 13A , second slit 1122 is formed such that the opening width W 2 is a predetermined opening width A more than zero when valve element 1121 does not receive an internal liquid pressure more than a set value. The opening width W 2 is a width in a direction orthogonal to the longitudinal direction of the opening given by second slit 1122 . [0076] When valve element 1121 receives an internal liquid pressure more than the set value of the inflow liquid having reached from the side of tube main body 3 opposite to inner peripheral surface 31 , valve element 1121 is deformed toward inner peripheral surface 31 side of tube main body 3 depending on the scale of the internal liquid pressure. As illustrated in FIG. 13B , valve element 1121 allows the opening width W 2 of second slit 1122 to be decreased such that the amount of decrease relative to the predetermined opening width A becomes larger as the internal liquid pressure is increased. There may be a lower limit value of the internal liquid pressure at which the deformation of valve element 1121 is started. [0077] FIGS. 14A to 14C illustrate the simulation results of the movement of flow rate control part 112 made of polypropylene. The thickness of valve element 1121 is 0.2 mm, and the opening width W 2 (A) of second slit 1122 when flow rate control part 112 does not receive the internal liquid pressure is 0.1 mm [0078] As illustrated in FIG. 14A , for example when the internal liquid pressure is increased to 0.01 MPa, the deformation of valve element 1121 and the decrease in the opening width W 2 of second slit 1122 associated with that deformation are started. As illustrated in FIG. 14B , for example when the internal liquid pressure is 0.05 MPa, the opening width W 2 of second slit 1122 is 0.05 mm, a half width of the original width A. As illustrated in FIG. 14C , for example when the internal liquid pressure is 0.10 MPa, the opening width W 2 of second slit 1122 is 0 mm Thus, dripper 1 may be used under pressure lower than 0.10 MPa, for example. [0079] <Specific Configuration of Guide Channel Part> [0080] As illustrated in FIGS. 4 to 9 , dripper 1 has, in bottom end surface 11 a , guide channel part 113 as a part of the channel part of substrate 11 . [0081] Guide channel part 113 is composed of a recess concaved from bottom end surface 11 a . Guide channel part 113 is formed in a predetermined area leftward from under inflow control part 111 such that the bottom surface of plate-like body 1111 is exposed downwardly. [0082] As illustrated in FIG. 10 , guide channel part 113 composes guide channel 21 for guiding the inflow liquid toward flow rate control part 112 side together with inner peripheral surface 31 of tube main body 3 , which seals the bottom end opening of the above recess. [0083] <Specific Configuration of Hollow Part> [0084] As illustrated in FIGS. 3 , 4 , 8 and 9 , dripper 1 has hollow part 114 as a part of the channel part of substrate 11 , at a position on the downstream side of guide channel part 113 and on the upstream side of flow rate control part 112 . Hollow part 114 is a cavity concaved from top surface 11 b . Hollow part 114 is formed such that the top surface of valve element 1121 is exposed upwardly and so as to be connected continuously to the terminal of guide channel part 113 (left end in FIG. 4 ). [0085] As illustrated in FIG. 9 , the upper opening of hollow part 114 is shielded from the outside of dripper 1 by plate-shaped first shielding wall part 23 . First shielding wall part 23 may be formed by bending a plate-shaped part having been molded integrally with substrate 11 using the same resin material as that of substrate 11 and being bendable so as to cover the opening of hollow part 114 afterward and then by heat-welding the plate-shaped part on the periphery of that opening (allowing the opening to be shielded). Alternatively, first shielding wall part 23 may be formed using another member (e.g., film sheet) having been manufactured in processes separated from those for substrate 11 and being joined so as to shield the upper opening of hollow part 114 . [0086] Hollow part 114 allows communication between guide channel part 113 and the channel in second slit 1122 . [0087] <Specific Configuration of Pressure Reduction Channel Part> [0088] As illustrated in FIGS. 4 and 9 , dripper 1 has, on bottom end surface 11 a , pressure reduction channel part 115 as a part of the channel part of substrate 11 . [0089] As illustrated in FIG. 4 , pressure reduction channel part 115 is a groove formed in bottom end surface 11 a . Pressure reduction channel part 115 is formed in an area from flow rate control part 112 side (left side) to ejection port 33 side (right side). The planar shape of pressure reduction channel part 115 is a serpentine shape (in other words, stream line shape or zig-zag shape) in the front-rear direction in FIG. 4 . Pressure reduction channel part 115 is formed at a position on the front side relative to guide channel part 113 so as not to interfere with guide channel part 113 . [0090] As illustrated in FIG. 10 , pressure reduction channel part 115 composes pressure reduction channel 22 together with inner peripheral surface 31 , which shields the bottom end opening of the groove, of tube main body 3 . Pressure reduction channel 22 allows the inflow liquid having passed through flow rate control part 112 to flow toward ejection port 33 while reducing the pressure of the inflow liquid. [0091] Pressure reduction channel 22 is allowed to communicate with the channel in second slit 1122 through a space surrounded by valve element 1121 , elevation surface 11 h and inner peripheral surface 31 of tube main body 3 . [0092] <Other Components> [0093] As illustrated in FIGS. 1 and 3 , in a predetermined area in the longitudinal direction on top surface 11 b , there is formed a recess having substantially the same width as the width of top surface 11 a . On the bottom of the recess, a plurality of plate-shaped convex parts 12 protruded upwardly and elongated in the front-rear direction are aligned at a predetermined interval between the adjacent parts in the longitudinal (left-right) direction of top surface 11 b . The length (length in the front-rear direction) of convex part 12 is shorter than the width of the recess, and there is a gap between each end of convex part 112 and the wall surface of the recess. A plurality of convex parts 12 function as a filter to prevent the inflow of relatively large foreign matter into the channel of dripper 1 . [0094] As illustrated in FIGS. 1 to 3 , between convex part 12 in top surface 11 b and inflow control part 111 , a plurality of groove parts 13 are aligned at a predetermined interval between the adjacent parts in the short-length (front-rear) direction of top surface 11 b . Groove part 13 is a strip of recess elongated in the left-right direction and recessed vertically downwardly. The right end surface of each of linear protrusions between a plurality of grooves 13 composes a part of first elevation surface 11 g , and the right end of each of a plurality of groove parts 13 is connected continuously to first elevation surface 11 g. [0095] Further, as illustrated in FIGS. 1 and 9 , second shielding wall part 24 is formed at a position corresponding to groove part 13 on top surface 11 b and inflow control part 111 . Second shielding wall part 24 shields both the upper opening of groove part 13 and the upper opening of first elevation surface 11 g . Between groove part 13 and second shielding wall part 24 , there is formed a channel for the irrigation liquid flowing toward inflow control part 111 from the recess. Second shielding wall part 24 may be formed in a method similar to that for first shielding wall part 23 . Principal Operation and Effect of Present Embodiment [0096] According to the present embodiment, the irrigation liquid in tube main body 3 is deprived of relatively large foreign matter by convex part 12 , and then reaches inflow control part 111 through between groove part 13 and second shielding wall part 24 . [0097] When the external liquid pressure of the irrigation liquid having reached inflow control part 111 does not amount to the set lower limit value, the rigidity of plate-like body 1111 in inflow control part 111 surpasses the external liquid pressure. Accordingly, elastic deformation of plate-like body 1111 does not occur. Thus, the opening width W 1 in first slit 1112 is maintained at zero (i.e., equivalent to the state where the external liquid pressure has no influence), thereby inhibiting the inflow of the irrigation liquid. [0098] When the external liquid pressure of the irrigation liquid having reached inflow control part 111 amounts to the set lower limit value, the external liquid pressure surpasses the rigidity of plate-like body 1111 . Accordingly, plate-like body 1111 (each segment 1111 a ) undergoes elastic deformation toward inner peripheral surface 31 side of tube main body 3 . Thus, first slit 1112 is expanded such that the opening width W 1 is increased from zero to a value depending on the external liquid pressure, thereby allowing the inflow of the irrigation liquid. [0099] The inflow liquid having been flowed out of inflow control part 111 reaches flow rate control part 112 after going through guide channel 21 and hollow part 114 sequentially. [0100] Valve element 1121 of flow rate control part 112 undergoes elastic deformation toward inner peripheral surface 31 side of tube main body 3 depending on the internal liquid pressure of the inflow liquid having reached flow rate control part 112 . Due to the elastic deformation, the opening width W 2 of second slit 1122 is decreased relative to the opening width W 2 (=A) where the internal liquid pressure has no influence, such that the amount of decrease in the flow rate of the liquid passing through flow rate control part 112 becomes larger as the internal liquid pressure is increased. For example, when the internal liquid pressure of the inflow liquid is less than a first set value of the internal liquid pressure, the opening width W 2 is an initial value A; when the internal liquid pressure of the inflow liquid is equal to or more than that first set value, the opening width W 2 becomes smaller than the initial value A; and when the internal liquid pressure of the inflow liquid is further raised to be equal to or more than a second set value, the opening width W 2 is zero. It is noted that a suitable lower limit value may be set depending on the thickness of valve element 1121 , the width of slit 1122 , or the like, as a lower limit value of the internal liquid pressure at which valve element 1121 undergoes elastic deformation. [0101] Due to the decrease in the opening width W 2 associated with the elastic deformation of valve element 1121 , the flow rate of the inflow liquid passing through the channel in second slit 1122 (flow rate of that inflow liquid flowing toward ejection port 33 side all at once) is regulated. [0102] The inflow liquid, of which flow rate is regulated by flow rate control part 112 , undergoes pressure reduction due to a pressure loss caused by the shape of the channel of pressure reduction channel 22 , and then is ejected outside of drip watering tube 2 from ejection port 33 . [0103] It is noted that the liquid flowed out of pressure reduction channel 22 is guided by a baffle part of which planar shape is a circular arc (see FIG. 4 ) so as to be diffused in a chamber in which ejection port 33 is formed. Further, since the above baffle part is disposed between the outlet of pressure reduction channel 22 and ejection port 33 , foreign matter having intruded into the above chamber from ejection port 33 are prevented from further intruding into pressure reduction channel 22 . [0104] Here, two drippers 1 disposed relatively on the upstream side and the downstream side will be discussed. [0105] In dripper 1 relatively on the upstream side, relatively high external liquid pressure causes the amount of the inflow liquid to be relatively large. At the same time, relatively higher internal liquid pressure also causes the flow rate limited by flow rate control part 112 to be relatively larger. Therefore, the amount of the inflow liquid to be ejected from ejection port 33 is not excessively large. [0106] In dripper 1 relatively on the downstream side, relatively low external liquid pressure causes the amount of the inflow liquid to be relatively small. At the same time, relatively lower internal liquid pressure also causes the flow rate limited by flow rate control part 112 to be relatively smaller. Therefore, the amount of the inflow liquid to be ejected from ejection port 33 is not excessively small. [0107] Accordingly, there is less variation in the amount of the inflow liquid to be ejected from ejection port 33 between ejection ports 33 on the upstream side and the downstream side (e.g., the variation may be limited to 5 to 10%). Thus, the amount of the inflow liquid to be ejected through individual ejection ports in drip watering tube 2 can be favorably controlled. The above-described effects can be surely achieved also in the case of performing long-distance watering using irrigation liquid with low liquid pressure, since dripper 1 is devised such that the pressure loss in tube main body 3 is alleviated, as described later. [0108] According to the present embodiment, the channel part, for composing the channel of dripper 1 , including inflow control part 111 is integrally formed into substrate 11 made of a resin material, and thus dripper 1 can be precisely manufactured at lower cost and at fewer processes and in a smaller size (in particular, reduced thickness). [0109] Alternatively, according to the present embodiment, the channel part for composing the channel including flow rate control part 112 is integrally formed into substrate 11 made of a resin material, thereby enabling such dripper 1 excellent in controlling the ejection amount of the irrigation liquid to be precisely manufactured at lower cost and at fewer processes and in a smaller size (in particular, reduced thickness). [0110] The smaller size (reduced thickness) of dripper 1 enables the area occupancy of dripper 1 with respect to a section of the channel in tube main body 3 to be reduced, and thus the pressure loss of the irrigation liquid in tube main body 3 can be limited. As a result, even when the liquid pressure (in other words, external liquid pressure) of the irrigation liquid to be supplied to drip watering tube 2 from the water source side is low, sufficient liquid pressure can be secured in an area up to the downstream side of tube main body 3 . Therefore, long-distance watering can be properly performed at a stable ejection amount. [0111] In addition, since inflow control part 111 is an integrally molded product with substrate 11 , a malfunction of inflow control part 111 caused by assembly error does not occur. Therefore, the inflow control and thus the ejection control of the irrigation liquid can be stabilized. [0112] In addition, since flow rate control part 112 is an integrally molded product with substrate 11 , a malfunction of flow rate control part 112 caused by assembly error does not occur. Therefore, the ejection amount of the inflow liquid can be further stabilized. [0113] Further, dripper 1 does not require an expensive material such as silicone rubber, and can be manufactured basically with a single inexpensive resin material. Therefore, the production cost can be reduced. In addition, the number of components and the number of manufacturing processes can also be surely reduced, compared to the dripper into which three components are assembled as disclosed in PTL 1. Thus, according to the present embodiment, cost reduction can be achieved. [0114] Furthermore, flow rate control part 112 is disposed at a position offset in a direction orthogonal to the thickness direction of substrate 11 with respect to inflow control part 111 . Therefore, it is further advantageous to make dripper 1 thinner. [0115] In addition, when each segment 1111 a receives the external liquid pressure from above, plate-like body 1111 of inflow control part 111 deflects downwardly and outwardly utilizing the elasticity of a resin material, in such a manner that the tips of the respective segments 1111 a are spaced apart from each other. Thus, segment 1111 a is formed into a suitable shape to expand first slit 1112 upon receiving the external liquid pressure efficiently, and thus the inflow control can be performed more properly. [0116] In addition, when each valve segment 1121 a receives the internal liquid pressure from above, valve element 1121 of flow rate control part 112 deflects downwardly and inwardly utilizing the elasticity of a resin material. As a result, the height of the upward protrusion of valve segment 1121 a is decreased, and at the same time the tips of the respective valve elements 1121 a come closer to each other. Thus, valve element 1121 is formed into a suitable shape to decrease the opening width W 2 of second slit 1122 upon receiving the internal liquid pressure efficiently, and thus the control of the flow rate toward ejection port 33 can be performed more properly. [0117] It is noted that the present invention is not limited to the above-described embodiments, and may be variously modified as long as the features of the present invention are not impaired. [0118] For example, plate-like body 1111 may have a shape other than the domed shape (e.g., pyramidal shape or flat shape) as necessary. [0119] For example, valve element 1121 may have a shape other than the domed shape (e.g., pyramidal shape) as necessary. [0120] For example, both plate-like body 1111 and valve element 1121 may be disposed so as to be protruded toward the center of tube main body 3 , or alternatively may be disposed so as to be protruded toward inner peripheral surface 31 of tube main body 3 . Further, plate-like body 1111 may be disposed so as to be protruded toward the center of tube main body 3 , with valve element 1121 being disposed so as to be protruded toward inner peripheral surface 31 of tube main body 3 . [0121] In addition, the inflow part does not need to be the inflow control part. For example, the inflow part may be mere a channel for liquid, such as a pore or a slit. In this case, the dripper has the flow rate control part, and achieves the effects obtained by the flow rate control part, among the above-described effects. [0122] In addition, the dripper does not need to have the flow rate control part when the dripper has the inflow control part. In this case, the dripper achieves the effects obtained by the inflow control part, among the above-described effects. [0123] All the contents disclosed in the specification, drawings and abstract of Japanese Patent Application No. 2012-216575 filed on Sep. 28, 2012 and Japanese Patent Application No. 2012-216576 filed on Sep. 28, 2012 are incorporated herein by reference. INDUSTRIAL APPLICABILITY [0124] The dripper according to the present invention is capable of supplying a stable amount of liquid without depending on the pressure of liquid inside a tube. Therefore, it is expected that the dripper and drip irrigation apparatus according to the present invention are utilized not only in drip irrigation but also in various industries where stable dropwise addition of liquid is demanded. REFERENCE SIGNS LIST [0000] 1 Dripper 11 Substrate 111 Inflow control part 112 Flow rate control part 1111 Plate-like body 1112 First slit 1121 Valve element 1122 Second slit 2 Drip watering tube 3 Tube main body 31 Inner peripheral surface 32 Outer peripheral surface 33 Ejection port

Dripper comprises Substrate integrally formed of a resin material and that includes a channel for an irrigating liquid. The channel comprises Inflow control part for controlling flowing in of the irrigating liquid and/or Flow rate control part for controlling the flow rate of the irrigating liquid that has flowed in. Inflow control part opens the channel in association with an increase in the pressure of the liquid to flow therein, and Flow rate control part closes the channel in association with an increase in the pressure of the liquid that has flowed in Dripper. Dripper is able to stabilize the control of inflow and discharge of the irrigating liquid, regardless of whether the pressure of the irrigating liquid increases or decreases, and also is able to achieve a reduction in manufacturing costs and improvement in manufacturing efficiency.

CROSS-REFERENCE TO RELATED APPLICATION This application incorporates by reference, and claims priority to and the benefit of, provisional U.S. Patent Application Ser. No. 60/388,458, which was filed on Jun. 12, 2002. TECHNICAL FIELD The invention relates to medical devices and, more specifically, to devices for approximation, ligation, or fixation of tissue using sutures. BACKGROUND INFORMATION Suturing of body tissue is a time consuming aspect of many surgical procedures. For many surgical procedures, it is necessary to make a large opening in the human body to expose the area that requires surgical repair. There are instruments available that allow for viewing of certain areas of the human body through a small puncture wound without exposing the entire body cavity. These instruments, called endoscopes, can be used in conjunction with specialized surgical instruments to detect, diagnose, and repair areas of the body that previously required open surgery to access. Some surgical instruments used in endoscopic procedures are limited by the manner in which they access the areas of the human body in need of repair. In particular, the instruments may not be able to access tissue or organs located deep within the body or that are in some way obstructed. Also, many of the instruments are limited by the way they grasp tissue, apply a suture, or recapture the needle and suture. Furthermore, many of the instruments are complicated and expensive to use due to the numerous parts and/or subassemblies required to make them function properly. Suturing instruments, and more specifically suturing instruments used in endoscopic procedures, are generally rigid and do not provide the operator a range of motion to access difficult to reach parts of the anatomical region requiring sutures. Accordingly, multiple instruments of various configurations and sizes must be used to access all of the necessary tissue areas. These limitations of suturing instruments complicate the endoscopic procedure for the surgeon by requiring the insertion and removal of multiple instruments from a surgical site as the target suturing area changes during the course of the surgical procedure. Many medical procedures require that multiple sutures be placed within a patient. Typical suturing instruments enable a surgeon to place only one suture at a time. With such suturing instruments, the surgeon is required to remove the instrument from a surgical site and reload the instrument between placing each suture. Further, the surgeon may be required to use forceps or other instruments to help place the suture. In some instances, the forceps or other instruments may require an additional incision to access the surgical site. Thus, suturing remains a delicate and time-consuming aspect of most surgeries, including those performed endoscopically. Accordingly, there is an unresolved need in the art to provide a suturing instrument with improved maneuverability, efficiency, and functionality during a surgical procedure. SUMMARY OF THE INVENTION The invention generally relates to surgical instruments for performing a surgical procedure, such as placing one or more sutures through tissue. The suturing instruments disclosed herein are dimensioned and configured to apply sutures to approximate, ligate, or fixate tissues in, for example, open, mini-incision, trans-vaginal, laparoscopic, or endoscopic surgical procedures. More particularly, in some embodiments, the invention is directed to suturing instruments that include a distal portion that is deflectably and/or pivotally coupled to the remainder of the instrument for improved maneuverability and functionality during surgery. In other embodiments the invention is directed to suturing instruments capable of housing multiple needle and suture assemblies and/or reloading the needle and suture assembly without removing the instrument from the surgical site. Such suturing instruments allow a surgeon to place multiple sutures without having to reload the instrument after each suture is placed, which is more efficient and less invasive than a procedure where the surgeon has to remove the instrument from the surgical site to reload. This is particularly helpful when the surgical site is located deep within a body and not easily repeatably accessible. In general, in a first aspect, the invention features a suturing instrument that includes an elongate body member having a middle portion and a distal portion. The distal portion extends distally from the middle portion and is deflectable at a predetermined angle relative to the middle portion. The predetermined angle of deflection of the distal portion may range from about −90° to about 90°. The suturing instrument also includes a needle deployment mechanism disposed at least partially within the elongate body member. The needle deployment mechanism is connectable to a needle for moving the needle out of the distal portion of the elongate body member. In one embodiment according to the first aspect of the invention, the elongate member also includes at least one tension member that is slidably disposed at least partially in the elongate member and is connected to its distal portion. In this embodiment, the suturing instrument may include at least one deflection control member coupled to the tension member and disposed opposite the distal portion of the elongate body member for controlling deflection of the distal portion. In another embodiment according to the first aspect of the invention, the distal portion is pivotable about a first axis that is perpendicular to the longitudinal axis of the elongate body member. In this embodiment, the suturing instrument may include a first pivot control lever disposed opposite the distal portion of the elongate body member, and a pivot wire rotatably disposed in the elongate body member and coupled to the distal portion. The first pivot control lever may be coupled to the pivot wire for controlling pivoting of the distal portion. In yet another embodiment according to the first aspect of the invention, the distal portion includes a first beveled surface for contacting the middle portion and the middle portion includes a second beveled surface for contacting the distal portion. According to one feature of this embodiment, a first angle defined by the first beveled surface and a second angle defined the second beveled surface are substantially equal. The sum of the angles may substantially equal 90°. According to another feature, the elongate body member includes a first resilient member for biasing the distal portion towards the middle portion along a longitudinal axis of the elongate member. The suturing instrument of this embodiment may also include a deflection control mechanism coupled to the distal portion for deflecting the distal portion at the predetermined angle relative to the middle portion by rotating the distal portion about a longitudinal axis of the elongate body member. In still another embodiment according to the first aspect of the invention, the elongate body member includes a locking mechanism for securing the distal portion at the predetermined angle relative to the middle portion. The locking mechanism may include a first plurality of teeth disposed on the first beveled surface and a second plurality of teeth disposed on the second beveled surface that are configured to mesh with the first plurality of teeth. Alternatively, the locking mechanism may include a plurality of detents that are defined by the first beveled surface and are circumferentially disposed about the first beveled surface; and a ball disposed in the second beveled surface and dimensioned to fit at least one of the plurality of detents. In this feature, the second beveled surface may define an aperture for receiving the ball therein. Also, a second resilient member may be disposed in the aperture for biasing the ball into engagement with the at least one of the plurality of detents. In yet another embodiment according to the first aspect of the invention, the needle deployment mechanism includes a needle carrier that is disposed at least partially within the distal portion of the elongate body member and is slidably movable out of the distal portion. The needle deployment mechanism optionally includes an actuator coupled to the needle carrier and disposed opposite the distal portion. The actuator may be at least partially housed by a handle disposed opposite the distal portion. The invention is also related generally to a method for placing sutures in tissue. The method includes the step of providing a suturing instrument having an elongate body member that includes a middle portion and a distal portion extending distally from the middle portion and deflectable at a predetermined angle relative to the middle portion; and a needle deployment mechanism disposed at least partially within the elongate body member and connectable to a needle for moving the needle out of the distal portion. The method further includes the steps of disposing a needle within the distal portion; disposing the suturing instrument in a body; deflecting the distal portion of the suturing instrument thereby positioning the distal portion proximal to the tissue; and actuating the needle deployment mechanism thereby moving the needle out of the distal portion and through the tissue. In general, in a second aspect, the invention features a suturing instrument that includes an elongate body member having a longitudinal axis. The elongate body member has a distal portion that is pivotable about at least one axis that is substantially perpendicular to the longitudinal axis of the elongate body member. The suturing instrument also includes a needle deployment mechanism disposed at least partially within the elongate body member. The needle deployment mechanism is connectable to a needle for moving the needle out of the distal portion. Also, the elongate body member may include a handle disposed opposite the distal portion. In one embodiment according to the second aspect of the invention, the suturing instrument also includes a pivot control lever disposed opposite the distal portion of the elongate body member for controlling pivoting of the distal portion. In a first version of this embodiment, the suturing instrument includes a pivot mechanism disposed in the elongate body member and coupled to the distal portion. The pivot control lever may be coupled to the pivot mechanism for controlling pivoting of the distal portion. In a second version of this embodiment, the elongate body member may include an inner portion coupled to the distal portion, and an outer portion coupled to the pivot control lever and slidably disposed at least partially along the inner portion. According to one feature, the suturing instrument also has a linkage coupled to the outer portion and the distal portion. The linkage is configured to cause the distal portion to pivot about the first axis when the outer portion is displaced relative to the inner portion. According to another feature, the suturing instrument also includes a resilient member for biasing the outer portion towards the proximal portion of the elongate body member. Further, in various features of the needle deployment mechanism of this embodiment of the suturing instrument, the needle deployment mechanism includes a needle carrier that is disposed at least partially within the distal portion of the elongate body member and is slidably movable out of the distal portion. According to one particular feature of the second version of this embodiment, the needle deployment mechanism also has a resilient loop of material disposed at least partially within the elongate body member and coupled to the needle carrier. The needle deployment mechanism also includes an actuator that is coupled to the needle carrier via the resilient loop of material to move the needle carrier of the distal portion. The actuator may be at least partially housed by the handle. According to another feature, the needle deployment mechanism also includes a needle carrier control rod that is slidably disposed at least partially within the elongate body member and coupled to the needle carrier. The needle carrier control rod may optionally be made of a superelastic material, such as a nickel-titanium alloy. The needle carrier control rod is configured to move the needle carrier when the needle carrier control rod is slidably advanced. The needle deployment mechanism may include an actuator coupled to the needle carrier control rod to advance the needle carrier control rod. The actuator is disposed opposite the distal portion of the elongate member, for example, at least partially housed by the handle. According to yet another feature of the second version of this embodiment, the needle deployment mechanism also includes a camshaft disposed within the distal portion of the elongate body member and coupled to the needle carrier and a drum rotatably disposed within the distal portion of the elongate body member and coupled to the camshaft for moving the camshaft when the drum rotates. The needle deployment mechanism according to this feature further includes a push wire slidably disposed within the elongate body member and having a distal end coupled to the drum for causing the drum to rotate. The needle deployment mechanism may also include an actuator coupled to a proximal end of the push wire for advancing the push wire. The actuator is disposed opposite the distal portion of the elongate member, for example, at least partially housed by the handle. In another embodiment according to the second aspect of the invention, the distal portion of the suturing instrument includes a first gear that is rotatable about a first axis substantially perpendicular to the longitudinal axis of the elongate body member. According to one feature of this embodiment, a middle portion of the elongate body member includes a second gear rotatable about the longitudinal axis and meshed with the first gear. According to this feature, the distal portion pivots about the first axis when the second gear rotates about the longitudinal axis. Optionally, the suturing instrument includes a pivot control mechanism disposed at least partially within the middle portion and coupled to the second gear for causing the second gear to rotate about the longitudinal axis, a pivot control lever disposed opposite the distal portion of the elongate body member and coupled to the pivot control mechanism for controlling pivoting of the distal portion. In yet another embodiment according to the second aspect of the invention, the distal portion is rotatable about the longitudinal axis of the elongate body member. In this embodiment, the suturing instrument may include a rotation control mechanism disposed opposite the distal portion of the elongate body member, and a rotation rod rotatably disposed in the elongate body member and coupled to the distal portion. The rotation control mechanism may be coupled to the rotation rod for controlling rotation of the distal portion. In general, in a third aspect, the invention features a suturing instrument for use with an endoscope. The suturing instrument according to this aspect of the invention includes an elongate body member having a flexible tubular member and a distal portion attached to a distal end of the flexible tubular member. The flexible tubular member is dimensioned to slidably and rotationally fit within a working channel of an endoscope. The suturing instrument according to this aspect of the invention also includes a needle deployment mechanism disposed at least partially within the elongate body member and connectable to a needle for moving the needle out of the distal portion. In one embodiment according to the third aspect of the invention, the needle deployment mechanism includes a needle carrier that is disposed at least partially within the distal portion of the elongate body member and is slidably movable out of the distal portion; a carrier drive wire slidably disposed within a lumen defined by the flexible tubular member and coupled to the needle carrier; and an actuator coupled to the carrier drive wire. According to one feature of this embodiment, the elongate body member may include a proximal portion including a handle at least partially housing the actuator. The tubular member may be releasably attached to the proximal portion. Optionally, the distal portion is rotatable about a longitudinal axis of the elongate body member relative to the proximal portion. The suturing instrument may also include a rotation control mechanism disposed in the proximal portion of the elongate body member for controlling rotation of the distal portion. Also, according to this feature, the proximal portion includes a carrier drive wire socket releasably coupled to the proximal portion for receiving the carrier drive wire. The proximal portion may also include a locking socket that is rotationally and releasably coupled to the carrier drive wire socket and serves to secure a proximal end of the tubular member. Further, the proximal portion may also include a scope adapter for securing the proximal portion to the working channel of the endoscope. In another embodiment according to the third aspect of the invention, the distal portion of the elongate body member is pivotable about a first axis, which is substantially perpendicular to a longitudinal axis of the elongate body member. Also, the invention features a method for placing sutures in tissue. The method includes the step of providing an endoscope defining a working channel through. The working channel of the endoscope has an opening at a distal end of the endoscope. The method further includes the step of providing a suturing instrument that includes an elongate body member having a flexible tubular member with a distal end and a proximal end; the flexible tubular member dimensioned to slidably and rotationally fit within the working channel of the endoscope, and a distal portion attached to the distal end of the flexible tubular member. The suturing instrument also includes a needle deployment mechanism disposed at least partially within the elongate body member and connectable to a needle for moving the needle out of the distal portion. The method also includes the steps of inserting the proximal end of the flexible tubular member into the opening; passing the flexible tubular member through the working channel of the endoscope, disposing a needle within the distal portion, disposing the endoscope within a body, positioning the distal portion proximal to the tissue, and actuating the needle deployment mechanism thereby moving the needle out of the distal portion and through the tissue. In various embodiments according to the foregoing aspects of the invention, the suturing instrument includes a needle disposed within the distal portion. Also, the distal portion of the suturing instrument of claim may include a needle catch configured to receive a needle, the needle catch defining a retention slot including at least two flexible edges. In general, in a fourth aspect, the invention features a suturing instrument that includes an elongate body member having a distal portion. The distal portion includes a needle catch defining an aperture. The suturing instrument according to this aspect of the invention includes a needle deployment mechanism disposed at least partially within the elongate body member for moving a needle out of the distal portion and to the needle catch as well as a needle reloading mechanism disposed at least partially within the elongate body member for pushing the needle into the aperture of the needle catch. The needle catch is optionally slidably movable along a longitudinal axis of the elongate body member. In one embodiment according to the fourth aspect of the invention, the needle deployment mechanism includes a needle carrier that is disposed at least partially within the distal portion of the elongate body member and is slidably movable out of the distal portion. The needle deployment mechanism also includes an actuator that is coupled to the needle carrier and disposed opposite the distal portion of the elongate body member. The needle carrier has a distal end that, optionally, defines a lumen for receiving the needle therein. In another embodiment according to the fourth aspect of the invention, the needle reloading mechanism includes a pusher rod and a rod actuator for moving the pusher rod towards the distal portion of the elongate body member. According to one feature of this embodiment, the rod actuator is disposed opposite the distal portion of the elongate body member substantially perpendicularly to the pusher rod. According to another feature, the pusher rod comprises a substantially concave distal end. Also, according to yet another feature, the needle reloading mechanism has a hook coupled to a resilient member for biasing the pusher rod away from the distal portion of the elongate body member. In still another embodiment according to the fourth aspect of the invention, the needle catch defines a retention slot including at least two flexible edges for retaining the needle therein, the retention slot in communication with the aperture. At least one of the flexible edges may have at least one protrusion extending into the retention slot. According to another feature of this embodiment, the suturing instrument includes a needle disposed within the distal portion. The needle has a suture attached thereto and is releasable from the needle catch by pulling on the free end of the suture after the needle reloading mechanism pushes the needle into the aperture. In yet another embodiment according to the fourth aspect of the invention, the suturing instrument also includes a handle disposed opposite the distal portion of the elongate body member, which at least partially houses the needle deployment mechanism and the needle reloading mechanism. In general, in a fifth aspect, the invention features a suturing instrument that includes an elongate body member having a distal portion. The distal portion includes a first operative portion and a second operative portion. The suturing instrument also includes a needle deployment mechanism that is disposed at least partially within the elongate body member and includes a first needle carrier disposed at least partially within the first operative portion and connectable to a first needle for moving the first needle out of the first operative portion, and a second needle carrier disposed at least partially within the second operative portion and connectable to a second needle for moving the second needle out of the second operative portion. In a first embodiment according to the fifth aspect of the invention, the suturing instrument includes a handle that is disposed opposite the distal portion of the elongate body member and at least partially houses the needle deployment mechanism. In a second embodiment according to the fifth aspect of the invention, the first operative portion and the second operative portion of the distal portion form a unitary operative portion. In a third embodiment according to the fifth aspect of the invention, the suturing instrument includes an actuator coupled to the first needle carrier and the second needle carrier and disposed opposite the distal portion of the elongate body member. According to one feature of this embodiment, the actuator includes a first sub-actuator coupled to the first needle carrier and a second sub-actuator coupled to the second needle carrier. The first needle carrier and the second needle carrier are actuatable either sequentially or simultaneously. In a fourth embodiment according to the fifth aspect of the invention, the suturing instrument includes a first needle disposed within the first operative portion, and a second needle disposed within the second operative portion. According to one feature of this embodiment of the suturing instrument, a first suture is attached to the first needle and a second suture is attached to the second needle. According to another feature of this embodiment, the suturing instrument includes a suture having a first end attached to the first needle and a second end attached to the second needle. In a fifth embodiment according to the fifth aspect of the invention, the distal portion of the suturing instrument includes a first needle catch configured to receive a first needle; and a second needle catch configured to receive a second needle. Optionally, the first needle catch and the second needle catch form a unitary needle catch. At least one of the first needle catch and the second needle catch may define a retention slot including at least two flexible edges. In a sixth embodiment according to the fifth aspect of the invention, the first operative portion of the distal portion defines a first needle port and the second operative portion of the distal portion defines a second needle port. In this embodiment, the distance between the first needle exit port and second needle exit port is laterally adjustable by deflecting at least one of the first operative portion and the second operative portion outwardly from the elongate body member. According to one feature of this embodiment, the suturing instrument includes a deflecting mechanism for adjusting the distance between the first needle exit port and the second needle exit port. A deflection actuator disposed opposite the distal portion of the elongate body member may be included for actuating the deflecting mechanism. The deflecting mechanism may include, for example, a wedge, a cam, an elbow linkage, a rotational separator, and a track-and-follower assembly. Lastly, in general, in a sixth aspect, the invention features a suturing instrument that includes an elongate body member having a distal portion. The distal portion includes a needle catch. The suturing instrument also includes a cartridge that is disposed at least partially within the distal portion and houses a first needle and a second needle, as well as a needle deployment mechanism that is disposed at least partially within the elongate body member and is connectable sequentially to the first needle and the second needle for moving the first needle and then the second needle from the cartridge out of the distal portion to the needle catch. The cartridge may be removable from the distal portion of the elongate body member or integrally formed within the distal portion. Also, the distal portion of the elongate body member is optionally rotatable relative to a remainder of the elongate body member. Further, in one embodiment of the sixth aspect of the invention, the needle deployment mechanism includes a needle carrier that is disposed at least partially within the distal portion of the elongate body member and is slidably movable out of the distal portion and an actuator coupled to the needle carrier and disposed opposite the distal portion of the elongate body member. In another embodiment of the sixth aspect of the invention, the cartridge defines an exit aperture for receiving at least one of the first needle and the second needle. According to one feature of this embodiment, the cartridge further defines a loading slot connected to the exit aperture. At least of the first needle and the second needle can be received in the loading slot. The second needle transitions from the needle loading slot to the exit aperture after the first needle is deployed from the cartridge. In one version of this feature, the suturing instrument includes a pusher for transitioning the second needle from the needle loading slot to the exit aperture after the first needle is deployed from the cartridge through the opening. Optionally, the pusher includes a push plate for contacting the second needle and a resilient member for biasing the push plate towards the exit aperture. In another version of this feature, the suturing instrument includes a suture having one end attached to the second needle, so that the second needle is transitioned from the loading slot to the exit aperture after the first needle is deployed from the cartridge by pulling on the free end of the suture. The suturing instrument may also include a means for pulling the free end of the suture optionally attached to the elongate body member and disposed opposite the distal portion thereof, such as, for example, a spool or a lever. In yet another embodiment of the sixth aspect of the invention, the cartridge also contains a third needle. In this embodiment, the needle deployment mechanism is connectable sequentially to the first needle and the second needle and the third needle for moving the first needle and then the second needle and then the third needle from the cartridge out of the distal portion to the needle catch. In still another embodiment of the sixth aspect of the invention, the suturing instrument includes a handle that is disposed opposite the distal portion of the elongate body member and at least partially houses the needle deployment mechanism. The invention also features a method for placing sutures in multiple tissue sites. The method includes the step of providing a suturing instrument having an elongate body member with a distal portion. The distal portion of the suturing instrument includes a needle catch. The suturing instrument also has a cartridge disposed at least partially within the distal portion. The cartridge includes a first needle disposed within the cartridge and a second needle disposed within the cartridge. Also, the suturing instrument includes a needle deployment mechanism disposed at least partially within the elongate body member and connectable sequentially to the first needle and the second needle. The method of the invention further contemplates the steps of disposing the suturing instrument in a body, positioning the distal portion proximal to a first tissue site in the body, actuating the needle deployment mechanism thereby moving the first needle out of the cartridge to the needle catch, positioning the distal portion proximal to a second tissue site in the body without withdrawing the suturing instrument from the body, moving the second needle in the cartridge, and actuating the needle deployment mechanism thereby moving the second needle out of the cartridge to the needle catch. In various embodiments according to the foregoing aspects of the invention, the elongate body member is adapted to access remote organs or tissue within a body. Also, the suturing instrument disclosed above may include one, two, or more bends. Advantages and features of the present invention herein disclosed will become apparent through reference to the following description, the accompanying drawings, and the claims. Furthermore, it is to be understood that the features of the various embodiments described herein are not mutually exclusive and can exist in various combinations and permutations. BRIEF DESCRIPTION OF THE DRAWINGS In the drawings, like reference characters generally refer to the same parts throughout the different views. Also, the drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention. In the following description, various embodiments of the present invention are described with reference to the following drawings, in which: FIG. 1A is a schematic plan view of one embodiment of a suturing instrument in accordance with the invention; FIG. 1B is a schematic cross-sectional view of a proximal portion of the suturing instrument of FIG. 1A ; FIG. 1C is a schematic cross-sectional view of a distal portion of the suturing instrument of FIG. 1A ; FIG. 2A is a schematic plan view of a needle coupled to a suture for use in a suturing instrument in accordance with the invention; FIG. 2B is a schematic perspective view of a needle catch for use with the suturing instrument of FIG. 1A ; FIG. 3A is a schematic perspective view of a distal portion of a suturing instrument including a multi-load needle cartridge in accordance with the invention; FIG. 3B is an enlarged cross-sectional view of the suturing instrument of FIG. 3A ; FIG. 4A is a schematic perspective view of a distal portion of a multi-needle suturing instrument in accordance with the invention; FIG. 4B is a schematic perspective view of an alternative multi-needle suturing instrument having two operative portions in accordance with the invention; FIG. 4C is an enlarged schematic perspective view of the operative portions of the suturing instrument of FIG. 4B in an aligned position; FIG. 4D is an enlarged schematic perspective view of the operative portions of the suturing instrument of FIG. 4B in a spread position; FIG. 4E is a schematic perspective view of a single suture placement in tissue; FIG. 4F is a schematic perspective view of a double suture placement in tissue; FIG. 5A is a schematic cross-sectional perspective view of a distal portion of a suturing instrument including a needle reloading mechanism in accordance with the invention; FIG. 5B is a schematic perspective view of a pusher rod for use with the suturing instrument of FIG. 5A ; FIG. 5C is a schematic cross-sectional perspective view of a proximal portion of the suturing instrument of FIG. 5A ; FIGS. 5D–5F are schematic plan views of the needle reloading mechanism of the suturing instrument of FIGS. 5A–5C in operation; FIG. 5G is a schematic cross-sectional view of a modified handle for use with the suturing instrument of FIGS. 5A–5C ; FIG. 5H is a schematic plan view of a modified elongate body member for use with the suturing instrument of FIGS. 5A–5C ; FIG. 6A is a schematic perspective view of one embodiment of a suturing instrument having a deflectable and pivotable distal portion in accordance with the invention; FIG. 6B is an enlarged schematic perspective view of the deflectable distal portion of the suturing instrument of FIG. 6A ; FIG. 6C is a schematic perspective view of the proximal portion of the suturing instrument of FIG. 6A ; FIG. 6D is a schematic perspective view of the deflection and rotation mechanisms of the suturing instrument of FIG. 6A ; FIG. 6E is a schematic perspective view of an alternative embodiment of a suturing instrument having a deflectable distal portion; FIGS. 6F–6H are schematic perspective views of the deflectable distal portion of the suturing instrument of FIG. 6E in different positions; FIG. 6I is a schematic cross-sectional view of the suturing instrument of FIG. 6E ; FIG. 6J is a schematic cross-sectional view of one embodiment of a locking mechanism for use with a suturing instrument in accordance with the invention; FIG. 6K is a schematic cross-sectional view of an alternative embodiment of the locking mechanism of FIG. 6J ; FIG. 7A is a schematic perspective view of a suturing instrument having a distal portion that is pivotable about one axis in accordance with the invention; FIGS. 7B and 7C are enlarged schematic perspective views of the pivotable distal portion of the suturing instrument of FIG. 7A ; FIG. 7D is a schematic perspective view of a suturing instrument including a distal portion that is pivotable about two axes in accordance with the invention; FIGS. 7E–7H are enlarged schematic perspective views of the distal portion of the suturing instrument of FIG. 7D ; FIGS. 8A–8C are schematic plan views of a suturing instrument including an alternative embodiment of a pivotable distal portion in accordance with the invention; FIG. 8D is an enlarged schematic view of the distal portion of the suturing instrument of FIG. 8A ; FIG. 8E is an enlarged schematic cross-sectional view of the distal portion of the suturing instrument of FIG. 8C ; FIG. 9A is a schematic plan view of a suturing instrument including an alternative embodiment of a pivotable distal portion of a suturing instrument in accordance with the invention; FIG. 9B is an enlarged schematic partial cross-sectional view of the distal portion of the suturing instrument of FIG. 9A ; FIG. 9C is an enlarged schematic partial cross-sectional view of the distal portion of the suturing instrument of FIG. 9A in a pivoted position; FIG. 10A is a schematic cross-sectional view of an alternative embodiment of a pivotable distal portion of a suturing instrument in accordance with the invention; FIG. 10B is a schematic cross-sectional view of the pivotable distal portion of FIG. 10A in a pivoted position; FIG. 11A is a schematic cross-sectional view of an alternative embodiment of a pivotable distal portion of a suturing instrument including a drum-and-camshaft needle deployment mechanism in accordance with the invention; FIG. 11B is a schematic cross-sectional view of the distal portion of the suturing instrument of FIG. 11A with a needle deployment mechanism in a deployed position; FIG. 12A is a schematic perspective view of a suturing instrument configured for use with an endoscope in accordance with the invention; FIG. 12B is a schematic perspective view of a distal portion of the suturing instrument of FIG. 12A attached to a sheath having a carrier drive wire disposed therein; and FIG. 12C is a schematic perspective view of a pivotable distal portion of the suturing instrument of FIG. 12A . DESCRIPTION Referring to FIG. 1A , in one embodiment, a suturing instrument 100 includes a handle 102 , an elongate body member 104 , and a needle deployment mechanism 110 disposed within the elongate body member 104 and the handle 102 . The suturing instrument 100 also includes a distal portion 106 and a proximal portion 108 . The elongate body member 104 is mechanically coupled to the handle 102 at the proximal portion 108 and the suturing components are at least partially disposed within the distal portion 106 of the suturing instrument 100 . The handle 102 can take a variety of forms, for example, the handle 102 could be one of the types compatible with suturing systems available from Boston Scientific Corporation of Natick, Mass., in particular with the Capio® Push & Catch suturing system. A suture clip 144 may be coupled to the handle 102 or the elongate body member 104 and used to hold an end of one or more sutures 136 prior to placement in a patient. Generally, the needle deployment mechanism 110 extends longitudinally through the elongate body member 104 to the distal portion 106 of the suturing instrument 100 , where the needle deployment mechanism 110 is coupled to a needle 128 (shown in FIG. 2A ). The needle deployment mechanism 110 moves the needle 128 between a retracted position and a deployed position. One possible needle deployment mechanism 110 is shown in greater detail in FIGS. 1B and 1C . Referring to FIG. 1B , in one embodiment, the proximal portion 108 of the suturing instrument 100 includes the handle 102 , the elongate body member 104 , the suture clip 144 , and the needle deployment mechanism 110 . The needle deployment mechanism 110 includes an actuator button 117 and a shaft 116 that together form an actuator 112 . The needle deployment mechanism 110 also includes a bearing 118 and a button end 119 that defines a hole 121 formed therein. The hole 121 is preferably formed along the central longitudinal axis of the button end 119 . The bearing 118 rides along the surface of a lumen 105 that is defined by the inside diameter of the elongate body member 104 . A wireform 103 is inserted into the hole 121 of the button end 119 , so that the wireform 103 is coupled to the actuator button 117 . A spring 115 encircles the wireform 103 , abuts the button end 119 , and is compressed between the button end 119 and a spring washer 113 . The spring washer 113 is seated upon a center tube 107 . The center tube 107 is housed by the lumen 105 and is constrained in the distal portion 106 . A pusher wire 111 is attached to the wireform 103 by means of a weld, a coupling, adhesive, or other means, and is slidably disposed within a guidance sleeve 109 , the sleeve 109 being disposed within the surface of a lumen 123 defined by the inside diameter of the center tube 107 . In one embodiment, the pusher wire 111 is constructed of an elastic material having “superelastic” properties. Such a material may include alloys of In—Ti, Fe—Mn, Ni—Ti, Ag—Cd, Au—Cd, Au—Cu, Cu—Al—Ni, Cu—Au—Zn, Cu—Zn, Cu—Zn—Al, Cu—Zn—Sn, Cu—Zn—Xe, Fe 3 Be, Fe 3 Pt, Ni—Ti—V, Fe—Ni—Ti—Co, and Cu—Sn. In the illustrative embodiment, the superelastic material is a nickel and titanium alloy, commonly known as Nitinol® available from Memry Corp of Brookfield, Conn. or SMA Inc. of San Jose, Calif., so chosen for its combination of properties that allow for bendability and high column strength when constrained. The ratio of nickel and titanium in Nitinol® may vary. One preferred example includes a ratio of about 50% to about 56% nickel by weight. Nitinol® also possesses shape retention properties. Referring to FIG. 1C , the distal portion 106 of the elongate body member 104 includes the distal components of the needle deployment mechanism 110 (described in detail below), an operative portion 126 , and a needle catch 122 . In one embodiment, the operative portion 126 has an arcuate shape and partially encircles a suturing field 176 . The operative portion 126 also defines a lumen 178 therein having a needle exit port 120 at an opening into the suturing field 176 . A needle 128 is disposed in the needle exit port 120 and is held in place by a slight friction fit. In one embodiment, the suture 136 is attached to the needle 128 . The free end of the suture 136 extends out of a suture slot 146 . Referring again to the needle deployment mechanism 110 , the pusher wire 111 is attached by welding or other means to a coupling 150 , which is slidably disposed within a track 152 . The coupling 150 is attached to a carrier wire 154 , which, by virtue of its attachment to the coupling 150 , is also slidably disposed within the track 152 . The coupling 150 abuts a backstop washer 156 that is slidably disposed about the pusher wire 111 and is contained within a pocket 160 that includes a back wall 162 , against which the backstop washer 156 rests. The track 152 terminates distally in a pocket 164 that includes a wall 166 . A downstop washer 158 is slidably disposed about the carrier wire 154 and constrained within the pocket 164 . The carrier wire 154 is mechanically coupled to an extendable needle carrier 124 by welding, coupling, use of adhesives, or by other means. The needle carrier 124 is slidably disposed in the lumen 178 of the operative portion 126 and has a lumen 125 formed at a distal end of the needle carrier 124 . The lumen 125 is dimensioned to releasably receive the non-penetrating end of the needle 128 . The needle carrier 124 is configured to push the needle 128 out of the needle exit port 120 through tissue proximate the suturing field 176 , and into the needle catch 122 , as will be described in further detail below. In one embodiment, the needle 128 is held within the lumen 125 by a slight friction fit. FIG. 2A depicts one embodiment of the needle 128 for use in a suturing instrument in accordance with the invention. In this embodiment, the needle 128 includes a penetrating tip 130 and a shaft 134 coupled to the tip 130 , thereby forming a shoulder 132 . The shaft 134 is coupled to the suture 136 . Other configurations of the needle 128 can also be used without deviating from the scope of the invention. As shown in FIG. 1C , in one embodiment, when the needle 128 is disposed in the needle exit port 120 , the free end of the suture 136 extends out of a needle carrier suture slot 148 and the suture slot 146 . Referring to FIG. 2B , the needle catch 122 includes openings 170 defined by successive ribs 172 . When the needle catch 122 receives the needle 128 coupled to the suture 136 through opening 170 , the ribs 172 deflect slightly to allow the needle 128 to pass through. After the shoulder 132 has passed the ribs 172 , the ribs 172 spring back to their original position defining the openings 170 , and the needle 128 remains captured in the needle catch 122 . The openings 170 are chosen to be smaller in dimension than the shoulder 132 . This causes the needle catch 122 to retain the needle 128 , because the flat rear surface of the shoulder 132 prevents the needle 128 from passing back through the opening 170 . When it is necessary to remove the needle 128 from the needle catch 122 , the needle 128 may be moved toward an enlarged portion 174 of the opening 170 . The enlarged portion 174 is sized to allow the shoulder 132 to pass through without resistance. The needle catch 122 may be constructed of thin stainless steel of high temper, such as ANSI 301 full hard. The needle catch 122 may be fabricated by means of stamping, laser machining, or chemical etching. Referring again to FIGS. 1A–1C and 2 A– 2 B, in operation, a user (such as a physician or other medical personnel) actuates the needle deployment mechanism 110 by pushing on the button 117 , which, via the attachment to the wireform 103 , is attached to the pusher wire 111 , moves the coupling 150 along the track 152 concomitantly moving the carrier wire 154 , which in turn slidably moves the needle carrier 124 through the lumen 178 towards the needle exit port 120 . The user continues to push the button 117 until the needle carrier 124 receives the needle 128 in the lumen 125 , and further until the needle 128 penetrates tissue proximate the suturing area 176 and then enters and is retained in the needle catch 122 . Then, the user releases the button 117 and the spring 115 urges the button 117 proximally, thereby moving the pusher wire 111 , the coupling 150 , the carrier wire 154 , and the needle carrier 124 proximally along with the button 117 to the retracted position. As the needle carrier 124 moves back to the retracted position, the needle 128 slides out of the lumen 125 and the needle is released from the needle carrier 124 . In one embodiment, after one or more sutures 136 have been placed, the user withdraws the suturing instrument 100 from the patient. The user then detaches one or more sutures 136 from one or more needles 128 and ties a knot or knots in the sutures 136 . The user can then use a knot pusher 184 to push one or more knots into the patient as the knots are tightened. The suturing instrument's component materials should be biocompatible. For example, the handle 102 , the elongate body member 104 , and portions of the needle deployment mechanism 110 may be fabricated from extruded, molded, or machined plastic material(s), such as polypropylene, polyethylene, polycarbonate, or glass-filled polycarbonate. Other components, for example the needle 128 , may be made of stainless steel. Other suitable materials will be apparent to those skilled in the art. The material(s) used to form the suture should be biocompatible. The surgeon will select the length, diameter, and characteristics of the suture to suit a particular application. Additionally, the mechanical components and operation are similar in nature to those disclosed in U.S. Pat. Nos. 5,364,408 and 6,048,351, and commonly owned U.S. patent application Ser. No. 10/210,984, each of which is incorporated by reference herein in its entirety. FIGS. 3A and 3B depict two embodiments of a suturing instrument having a multi-load cartridge 140 in accordance with the invention. Such a suturing instrument advantageously allows the user to place multiple sutures without removing the suturing instrument from the surgical site. According to both embodiments, the suturing instrument 100 includes the cartridge 140 that houses two or more needles 128 disposed therein. Referring to FIG. 3A , the cartridge 140 is integrally formed within the distal portion 106 . In this embodiment, the distal portion 106 defines a sidewall access opening 141 to allow the user to load one or more needles 128 into the cartridge 140 . Referring to FIG. 3B , the cartridge 140 is either integrally formed or removably disposed at a distal end 142 of the operative portion 126 . Having a removable cartridge allows the user to choose a cartridge having a specific number of needles for a specific application. Also, the suturing instrument 100 may be reusable with different needle cartridges. Referring still to FIG. 3B , the multi-load needle cartridge 140 defines an exit aperture 145 and a needle loading slot 147 . The multi-load needle cartridge 140 is designed to hold essentially any number of needles, for example, 2–20 needles. The multi-load needle cartridge 140 is preloaded and capable of feeding the needle and suture assembly into the needle carrier 124 . In one embodiment, the cartridge 140 can be reloaded by the user in situ by adding needles 128 using, for example, the sidewall access opening 141 ( FIG. 3A ) or the exit port 120 ( FIG. 3B ). The multi-load needle cartridge 140 may include a push plate 196 and a spring 198 that biases the push plate 196 towards the exit aperture 145 . Both embodiments operate in essentially the same manner, enabling a user to place multiple sutures 136 in a patient without removing the suturing instrument 100 from the surgical site. As described above, the preloaded multi-load needle cartridge 140 can include one or more needles 128 each with the suture 136 coupled thereto. Referring to FIG. 3B , in one embodiment, the needle cartridge 140 includes three needles 128 a , 128 b , 128 c . Sutures 136 a , 136 b , 136 c extend out of the suture slot 146 . Alternatively, the sutures 136 may run through the elongate body member 104 . The first needle 128 a is disposed in the exit aperture 145 , and the remaining needles 128 b , 128 c are disposed in the loading slot 147 . The needle carrier 124 , which is part of the needle deployment mechanism 110 , is sequentially connectable to the needles 128 stored in the cartridge 140 . This means that each needle 128 stored in the needle cartridge 140 is connected to, and then deployed by, the needle carrier 124 one at a time in the order the needles 128 are dispensed from the needle cartridge 140 . In operation, the user inserts the elongate body member 104 into a patient and orients the elongate body member 104 so that the tissue to be sutured is disposed proximate the suturing field 176 and the needle exit port 120 is proximate to or in contact with the tissue. The user then pushes the button 117 ( FIG. 1B ), as described above. Pushing the button 117 causes the needle carrier 124 to receive the needle 128 a in the lumen 125 and then to extend out of the needle exit port 120 and push the needle 128 a through the tissue. As the first needle 128 a is pushed through the tissue, the first needle 128 a pulls the first suture 136 a through the tissue. As the user continues to push the button 117 , the needle carrier 124 continues to advance out of the needle exit port 120 and directs the first needle 128 a and the first suture 136 a toward the needle catch 122 . The user continues to push the button 117 until the first needle 128 a contacts and becomes captured by the needle catch 122 . The user then retracts the needle carrier 124 by releasing the button 117 , as previously described. After the user retracts the needle carrier 124 , the first needle 128 a and the first suture 136 a are left captured within the needle catch 122 , with the first suture 136 a extending through the tissue. When the needle carrier 124 returns to a fully retracted position, the spring 198 causes the needle push plate 196 to push the second needle 128 b into the exit aperture 145 . The needle 128 b is thereby forced through the loading slot 147 and either into the lumen 125 of the needle carrier 124 or in position to be captured by the needle carrier 124 . The second suture 136 b extends out of the suture slot 146 . The user then advances the needle carrier 124 as described above until the second needle 128 b is captured by the needle catch 122 . The user then retracts the needle carrier 124 as described above leaving the second needle 128 b and the second suture 136 b captured by the needle catch 122 . This procedure can be repeated for the third needle 128 c , or for as many needles as may be stored in the needle cartridge 140 . After one or more sutures 136 have been placed, the user withdraws the suturing instrument 100 from the patient. The user detaches the suture(s) 136 from the needle(s) 128 and ties a knot or knots in the suture(s) 136 . The user can then use the knot pusher 184 to push the knot(s) in the patient as the knot(s) is tightened. Alternatively, other mechanisms could be used to advance the needle 128 from the needle cartridge 140 to the carrier 124 . In one embodiment, the needles 128 in the needle cartridge 140 are held in the loading slot 147 by a friction fit and are pushed into the exit aperture 145 when the needle push plate 196 is activated by the user. For example, instead of the spring 198 , a dispensing control rod coupled to a button on the handle 102 and the push plate 196 may be provided. Alternatively, a spring release mechanism coupled to the spring 198 and a button on the handle 102 may be provided to enable the user to release the spring 198 so that the push plate loads the needle 128 into the exit aperture 145 to be received in the lumen 125 of the needle carrier 124 . In another embodiment, the user may load the needle 128 into the exit aperture 145 by pulling the free end of the suture 136 . In yet another embodiment, the suturing instrument 100 may include a means for pulling the free end of the suture 136 such as, for example, a spool or a lever attached to the elongate body member and disposed, for example, on or within the handle 102 . Referring to FIG. 4A , in another embodiment, the operative portion 126 of the distal portion 106 of the suturing instrument 100 includes a mechanism for deploying two or more needles 128 . The needles 128 can be deployed sequentially or simultaneously. The deployment mechanism includes a separate needle carrier 124 a , 124 b for each needle 128 . The handle 102 can include one button 117 to advance both needles 128 or the handle 102 can include two buttons 117 a , 117 b to advance the needles 128 sequentially or simultaneously (if pressed at the same time). Passing two single armed needles into an incision site enables a user to place, for example, two ligating sutures simultaneously, withdrawing the device, and tying two knots. Ligating between the sutures is possible in a shorter time-frame. In operation, this embodiment functions largely the same way as the embodiments previously described. For simultaneous advancement, the user advances the needle carriers 124 by pressing the button(s) 117 ( FIG. 1A ) until the needles 128 are driven through the tissue and captured by the needle catch 122 . After the needles 128 are captured in the needle catch 122 , the needle carriers 124 are retracted. For sequential advancement, the user advances one needle carrier 124 a by pressing one button 117 a until the first needle 128 a is driven through the tissue and captured by the needle catch 122 . The user then retracts the first needle carrier 124 a . The user then advances the second needle carrier 124 b by pressing the second button 117 b until the second needle 128 b is driven through the tissue and captured by the needle catch 122 . The user then retracts the second needle carrier 124 b. Referring to FIGS. 4B–4D , in another embodiment, the distal portion 106 includes two separate operative portions 126 a , 126 b separated a wedge 200 . The operative portions 126 a , 126 b include the needle exit ports 120 a , 120 b that are deflectable or spreadable outward relative to the elongate member 104 to adjust the distance between the exit ports 120 a , 120 b . The user may control the amount of separation between the operative portions 126 a , 126 b and, therefore, the distance between the exit ports 120 a , 120 b with a control lever 202 in the handle 102 . Other mechanisms that can be used to deflect the operative portions 126 a , 126 b include, but are not limited to, a cam or link, an elbow linkage, a rotational separation along a longitudinal axis 350 of the device, a pre-made track and follower assembly, or a manual separator. In a particular embodiment, the user actuates the control lever 202 , thereby advancing the wedge 200 and widening the space between the two operative portions 126 a , 126 b. One benefit of the embodiments depicted in FIGS. 4A–4D and described above is that spreading the operative portions 126 a , 126 b allows a user to create a controlled or predetermined distance between the needle carriers' tissue entrance points. This feature enables the placing of sutures 136 at different spacing sequences. In addition, these embodiments also provide a means to place a double-armed suture (a suture with a needle at each end) in a patient. Referring to FIGS. 4E and 4F , the needle deployment mechanism 110 generally functions the same way as previously described and can be used to place a single suture 136 coupled to two needles 128 a , 128 b through tissue 204 ( FIG. 4E ) or to place two sutures 136 a , 136 b coupled to two needles 128 a , 128 b , respectively ( FIG. 4F ) through tissue 204 . Referring to FIG. 4E , where a single suture 136 is attached to the two needles 128 a , 128 b , the suture 136 is placed perpendicularly to the longitudinal axis 350 of the suturing instrument. Referring to FIG. 4F , where separate sutures 136 a , 136 b are attached to each of the two needles 128 a , 128 b , the sutures 136 a , 136 b can be placed in essentially any orientation relative to the longitudinal axis 350 of the suturing instrument. Referring to FIGS. 5A–5H , in yet another embodiment, the suturing instrument 100 is modified to allow the user to place a so-called “whip stitch,” i.e., a continuous running suture. Typically, the suturing instrument must be removed from the surgical site so the user may disengage the needle from the needle catch and either reload the existing needle into the needle carrier or load a new needle and suture into the instrument. In this embodiment, the user can remove the needle from the catch and reload the needle into the needle carrier without removing the suturing instrument 100 . This allows the user to place a running stitch. This embodiment may be combined with any number of the other embodiments described herein. Generally, the instrument is used to secure tissue with a continuous running suture by passing the suture through tissue, catching the suture needle, ejecting the needle from the catch in situ, and reloading the needle into the carrier. The suturing instrument 100 essentially operates in the same manner as the other instruments described herein. The instrument is modified, however, to add a needle reloading mechanism 205 described in detail below that, when advanced, pushes the needle 128 along the needle catch 122 to an opening that permits the needle to be discharged from the catch 122 . The needle 128 can be discharged by, for example, pulling on the suture 136 . Continued pulling on the suture 136 can reposition the needle 128 into the end of the needle carrier 124 . The reloaded carrier 124 can then be advanced again, continuing suture placement through multiple tissue passes, resulting in a whip stitch. FIG. 5A depicts the distal portion 106 of the suturing instrument 100 . The needle carrier 124 and needle catch 122 are disposed in the distal portion 106 . The needle catch 122 is similar to the catch described hereinabove with respect to FIG. 2B ; however, the catch 122 is slightly modified to include two protrusions 210 disposed between the ribs of the center opening 213 to create a narrow portion in the opening 213 . The protrusions 210 prevent the needle 128 from moving to the larger opening, i.e., the needle reloading aperture 174 , in the catch 122 before the suturing instrument 100 is ready for reloading. In one embodiment, the needle catch 122 is slidably movable towards the needle exit port 120 . FIG. 5B depicts a needle reloading mechanism 205 . The mechanism 205 includes a pusher rod 208 and an actuator 206 . The actuator 206 is generally perpendicularly disposed relative to the rod 208 and is attached to the rod 208 by, for example, welding or other attachment means. Additionally, the mechanism 205 includes a hook 211 that couples to a spring 207 located within the handle 102 ( FIG. 5C ). The spring 207 acts to return the mechanism 205 to its original position once the actuator 206 is released. In a particular embodiment, the mechanism 205 is slidably disposed within the suturing instrument 100 . Referring to FIG. 5C , the proximal portion 101 of the suturing instrument 100 is modified compared to the embodiment shown in FIG. 1A . Specifically, the handle 102 is modified to house at least a portion of the mechanism 205 , as well as to include a slot 209 to house the actuator 206 . FIGS. 5D–5F are enlarged partial views of the needle catch 122 and pusher rod 208 . As shown, the needle 128 is held within the center opening 213 of the catch 122 between two ribs or flexible edges 172 . The pusher rod 208 includes a concave distal end that at least partially surrounds the needle 128 when the rod 208 is advanced into contact with the needle 128 ( FIG. 5E ). The pusher rod 208 pushes the needle 128 along the center opening 213 to the larger opening 174 . The needle 128 is moved past the protrusions 210 by the force of the pusher rod 208 . The force causes the ribs 172 to spread slightly to allow the needle 128 to pass. When the pusher rod 208 is fully advanced, the needle 128 will be positioned within the reloading aperture 174 ( FIG. 5F ). Alternatively, the needle 128 could be held within one of the lateral openings 215 , 217 in a catch 122 further modified to include protrusions 210 in the lateral openings 215 , 217 . The pusher mechanism 205 can also be modified to push a needle 128 held in one or both of the lateral openings 215 , 217 . FIG. 5G depicts the modified handle 102 . As described hereinabove, the handle 102 includes the slot 209 for the actuator 206 and a void 217 for housing the proximal portion of the rod 208 and the spring 207 and hook 211 . While the actuator 206 described herein is slidably disposed within the handle 102 , other mechanical linkages are contemplated, for example, a push button and push wire assembly. The dimensions shown are for illustrative purposes only and are not meant to be limiting. FIG. 5H depicts the modified elongate body member 104 compared to the embodiment depicted in FIG. 1A . The body member 104 is modified to house at least partially the pusher mechanism 205 , specifically the pusher rod 208 . The body member 104 includes a slot 219 that runs substantially the entire length of the body member 104 . The pusher rod 208 is slidably disposed within the slot 219 . Operation of the instrument is described generally with reference to FIGS. 5A–5H . The basic operation is similar to that described hereinabove with reference to FIGS. 1A–1C , insofar as the user presses the button 117 thereby advancing the needle carrier 124 and pushing the needle 128 into the catch 122 . After the user drives the needle through the tissue 204 and into the catch 122 , the user positions the distal portion 106 of the suturing instrument 100 so that the tissue 204 is no longer in the surgical field 176 . During operation, the suture 136 is preferably maintained in tension. A free end of the suture 136 remains outside of the surgical site and accessible to the user. Next, the user advances the needle reloading mechanism 205 into contact with the needle 128 by pushing the actuator 206 distally. Once the pusher mechanism 205 is fully advanced, the needle 128 is positioned within the needle reloading aperture 174 . In this position, the free end of the suture 136 can be pulled to release the needle 128 from the catch 122 and, in turn, lead the needle 128 into the needle carrier. In addition, the needle carrier can be partially advanced to assist reloading of the needle 128 into the carrier. Also, the distal end of the needle carrier 124 can be modified to facilitate reloading. For example, the distal end of the carrier 124 and the lumen 125 could be enlarged to create a sufficient lead in for recapturing the needle 128 . Further, as described above, the needle catch 122 may be slidable distally to position the needle 128 close to the carrier 124 before releasing the needle 128 . After the needle 128 is recaptured in the lumen 125 of the needle carrier 124 and the needle carrier 124 is fully retracted into the operative portion 126 , the user maneuvers the suturing instrument 100 and/or the tissue 204 so that the tissue 204 is disposed again proximate the suturing field 176 and the exit port 120 is proximate to the next stitching position in the tissue 204 . Referring to FIGS. 6A and 6B , in another embodiment, the suturing instrument 100 includes a distal portion 106 that is independently deflectable and/or pivotable relative to the elongate member 104 . Specifically, the distal portion 106 includes a deflectable portion 300 that connects the elongate body member 104 to the distal portion 106 . The distal portion 106 is deflectable relative to the elongate member 104 in the “A-P” and “I-S” directions. Also, the operative portion 126 of the distal portion 106 may be pivotable about pivot nodes that define an axis 330 perpendicular to the longitudinal axis 350 of the elongate member 104 . Alternatively, the operative portion 126 of the distal portion 106 may be pivotable about a pin 402 that is perpendicular to the longitudinal axis 350 of the elongate member 104 and defines the axis 330 . Referring to FIGS. 6C and 6D , movements of the distal portion 106 are controlled by one or more deflection control members 302 , 306 , and/or a pivot control lever 304 included in the proximal portion 108 , for example, in the handle 102 . The deflection control members 302 are coupled to a tension roller 315 . The deflection control members 306 are coupled to a tension roller 311 . Tension members 335 are connected to the tension rollers 311 , 315 , extend through the elongate member 104 , and are coupled to a front portion 301 a of a deflectable portion 300 for causing the distal portion 106 to deflect. The pivot control lever 304 is coupled to a pivot wire 334 that extends along the longitudinal axis 350 of the elongate member 104 and is coupled to the operative portion 126 of the distal portion 106 to cause it to pivot. The tension members 335 and the pivot wire 334 pass through a wire equalizer 313 disposed within the elongate body member 104 and are formed from, for example, stainless steel or Nitinol® alloy. In operation, the user can pivot the operative portion 126 of the distal portion 106 about the axis 330 perpendicular to the longitudinal axis 350 of the elongate body member 104 by manipulating the pivot control lever 304 in the handle 102 . The pivot control lever 304 , when turned, causes the pivot wire 334 to pull or push the operative portion 126 , thereby rotating it around the axis 330 . The deflection control members 302 , 306 cause the tension rollers 311 , 315 to turn when the deflection control members 302 , 306 are turned, thereby causing the distal portion 106 to bend. Specifically, the user can bend the deflectable portion 300 of the distal portion 106 at its rear portion 301 b up to +/−90 degrees (A-P direction) by manipulating the deflection control member 302 , that causes the tension roller 315 to rotate and either tighten the tension member 335 a and relax the tension member 335 p , or tighten the tension member 335 p and relax the tension member 335 a . The user can also bend the deflectable portion 300 at its rear portion 301 b up to +/−90 degrees (I-S direction) by manipulating the deflection control member 306 , that causes the tension roller 311 to rotate and either tighten the tension member 335 i and relax the tension member 335 s , or tighten the tension member 335 s and relax the tension member 335 i. Referring to FIGS. 6E–6H , in another embodiment, the suturing instrument 100 includes a distal portion 106 having a beveled surface 307 a for contacting the elongate body member 104 and the elongate body member includes a beveled surface 307 b for contacting the distal portion. According to one feature of this embodiment, the acute angle defined by the beveled surface 307 a and the acute angle defined the beveled surface 307 b are substantially equal. In one embodiment, each of these angles substantially equals 45 degrees. The surfaces 307 a , 307 b are secured against each other by a spring 310 disposed in the elongate member 104 . In an aligned position, the surfaces 307 a , 307 b are aligned such that the distal portion 106 and the elongate body member 104 combine to produce a shaft that is substantially linear. The handle 102 includes a deflection control lever or member 312 that is coupled to a first end of a rod 320 that extends through the elongate member 104 . A second end of the rod 320 is coupled to the distal portion 106 . When the user manipulates the deflection control lever 312 , the distal portion 106 rotates and, by virtue of the contacting beveled surfaces 307 a , 307 b , a rotation point 308 forms, thereby enabling suturing of tissue at any angle relative to the elongate body member's longitudinal axis 350 (or angles of surface contact). In the embodiment shown in FIG. 6J , the suturing device 100 includes a locking mechanism that includes a ball 314 and a plurality of detents 316 . The ball 314 is coupled to the beveled surface 307 b of the elongate member 104 at a point radially outward from the longitudinal axis 350 of the distal portion 106 . The ball 314 is positioned on the elongate member 104 to allow it to contact the beveled surface 307 a of the distal portion 106 . Each of the plurality of detents 316 may be disposed equally about the circumference about the beveled surface 307 a of the distal portion 106 . The circle of detents 314 may be centered on the longitudinal axis of the distal portion 106 . Each detent 316 may have a radial distance from the longitudinal axis of the distal portion 106 equal to that of the ball 314 . As the user deflects the distal portion 106 by manipulating the deflection control lever 312 , the ball 314 moves out of one detent 316 and into another detent 316 . The detents are spaced such that the distal portion rotates in a stepwise manner. Each step may be a fixed number of degrees of rotation. In another embodiment, the ball 314 is coupled to a spring 318 disposed in an aperture 321 formed in the beveled surface 307 b . The spring 318 provides enough force to keep the ball 314 socketed in one of the detents when the user is not trying to change the angle of the distal portion 106 relative to the longitudinal axis 350 of the elongate body member 104 . The spring 318 is, however, compressible such that the ball 314 is at least partially withdrawn into the aperture 321 and the user can easily change the angle of the distal portion 106 relative to the longitudinal axis 350 of the elongate body member 104 by moving the ball 314 from one detent 316 a to another detent 316 b. In another embodiment, shown in FIG. 6K , the distal portion 106 and the elongate member 104 may include meshed teeth 319 a , 319 b that engage to lock the distal portion 106 and the elongate member 104 at a particular angle. In operation, the user pushes the distal portion 106 distally from the elongate member 104 , so the beveled surfaces 307 a , 307 b do not contact each other and the teeth 319 a , 319 b no longer engage, and then deflects the distal portion 106 to a desired angle. Then, when the beveled surfaces 307 a , 307 b are brought into contact with each other, the teeth 319 a , 319 b engage or mesh to lock the distal portion 106 in place. Referring to FIGS. 7A–7C , in another embodiment, the suturing instrument 100 includes a distal portion 106 that is independently pivotable about the axis 330 perpendicular to the longitudinal axis 350 of the elongate member 104 and rotatable about the longitudinal axis 350 of the elongate member 104 . In one version of this embodiment, the degree of pivot is controlled by a pivot control lever 400 located on the handle 102 and coupled to a pivot control mechanism disposed within the elongate member 104 . The pivot control mechanism is coupled to the distal portion 106 . When the user manipulates the pivot control lever 400 slidably moving the pivot control mechanism within the elongate member 104 , the distal portion 106 pivots about the pivot axis 330 . This embodiment enables the suturing of tissue at angles up to 90 degrees from the longitudinal axis 350 of the elongate body member 104 . The suturing instrument 100 also allows for removal from a 10 mm trocar without repositioning the distal portion 106 . Referring to FIGS. 7D–7H , in an alternative embodiment, the suturing instrument 100 includes a pivoting and rotating distal portion 106 . The suturing instrument 100 also includes a pivot control lever 504 , a rotation control lever 506 , and a needle deployment trigger 502 . The user can pivot the distal portion 106 by manipulating the pivot control lever 504 on the handle 102 . The distal end 106 can be pivoted to a position perpendicular to the tissue plane to be sutured. The internal operation of the pivoting mechanism is similar to embodiments discussed above. The user can also rotate the distal portion 106 by manipulating the rotation control lever 506 also disposed on the handle 102 , that is coupled to a rotation mechanism, which, in turn, is coupled to the distal portion 106 . The needle 128 is deployed by pulling the needle deployment trigger 502 . The needle deployment mechanism operates similar to other embodiments previously described. Referring to FIGS. 8A–8E , in another embodiment, the suturing instrument 100 includes a pivoting distal portion 106 and a pivot control lever 508 . The elongate member 104 includes an outer portion 516 and an inner portion 518 , and is coupled to the distal portion 106 at a pivot point 514 and via linkage 512 ( FIG. 8D ). The user controls the pivoting action by manipulating the pivot control lever 508 , thereby causing the outer portion 516 to slide relative to the inner portion 518 . Pushing the control lever 508 causes the outer portion 516 to push the linkage 512 , which, in turn, pushes the distal portion 106 . As the distal portion 106 is pushed by the linkage 512 , the distal portion pivots about the pivot point 514 . The distal portion 106 can pivot up to 90 degrees relative to the longitudinal axis 350 of the elongate body member 104 . Pulling the control lever 508 causes the outer portion 516 to pull the linkage 512 , which pulls the distal portion 106 . As the distal portion 106 is pulled by the linkage 512 , the distal portion 106 pivots about the pivot point 514 and returns to its original position. In one embodiment, the control lever 508 maybe be coupled to the outer portion 516 via a pin 509 or other attachment means. Alternatively, the control lever 508 is not coupled to the outer portion 516 , but is pushed into contact with the outer portion 516 via, for example, the pin 509 . Further, the outer portion 516 may be biased against the control lever 508 by a spring that causes the distal portion 106 to return to its starting position when the control lever 508 is released. According to this embodiment of the invention, in one version, the needle deployment mechanism 110 includes a loop 510 for advancing the needle carrier 124 . The loop 510 is formed from a resilient material, such as rubber. The loop 510 is coupled to the button 117 at the proximal end of the elongate member 104 and coupled to the needle carrier 124 at a distal end. In operation, the user presses the button 117 , which causes the loop 510 to advance. As the loop 510 advances, the needle carrier 124 , which is coupled to the loop 510 , also advances until the needle 128 in the needle carrier 124 is captured by the needle catch 122 . After the needle 128 is captured in the needle catch 122 , the user releases the button 117 and the loop 510 retracts thereby causing the needle carrier 124 to also retract. Referring to FIGS. 9A–9C , in another version of this embodiment, the needle deployment mechanism 110 in the distal portion 106 includes a first gear 520 , a second gear 524 , and a linkage 522 . The linkage 522 is coupled to the first gear 520 and the needle carrier 124 . In operation, the user manipulates the button 117 , which causes the second gear 524 to turn. The second gear 524 engages the first gear 520 , thereby causing the first gear 520 to turn and pivot the distal portion 106 . As the first gear 520 turns, the linkage 522 moves and advances the needle carrier 124 until the needle 128 is captured by the needle catch 122 . After the needle 128 is captured by the needle catch 122 , the user releases the button 117 and the first gear 524 and the second gear 520 turn in the opposite direction causing the linkage 522 to retract the needle carrier 124 . Referring to FIGS. 10A and 10B , in yet another embodiment, the needle deployment mechanism in the distal portion 106 includes a superelastic pusher 602 . A proximal end of the superelastic pusher 602 is coupled to the button 117 (shown in FIG. 1B ) and a distal end of the superelastic pusher 602 is coupled to the needle carrier 124 . In operation, the user pushes the button 117 , which causes the superelastic pusher 602 to advance the needle carrier 124 until the needle 128 is captured in the needle catch 122 . After the needle 128 is captured by the needle catch 122 , the user releases the button 117 and the superelastic pusher 602 retracts the needle carrier 124 . This embodiment operates similarly to the embodiment described with reference to FIGS. 1A–1C . The superelastic pusher can be formed from an elastic material having “superelastic” properties, such as Nitinol®. Referring to FIGS. 11A and 11B , in another embodiment, the needle deployment mechanism in the distal portion 106 includes a drum 608 and a camshaft 604 . The drum 608 is coupled to a distal end of a push wire. A proximal end of the push wire is coupled to the button 117 . The drum 608 is also coupled to the camshaft 604 and the camshaft 604 is coupled to the needle carrier 124 . In operation, the user pushes the button 117 , which causes the push wire to rotate the drum 608 . As the drum 608 rotates, the camshaft 604 moves and advances the needle carrier 124 until the needle 128 is captured in the needle catch 122 . After the needle 128 is captured by the needle catch 122 , the user releases the button 117 and the push wire rotates the drum 608 in the opposite direction, thereby causing the camshaft 604 to retract the needle carrier 124 . The push wire can be formed from, for example, stainless steel or nickel-titanium alloy. Referring to FIGS. 12A–12C , in still another embodiment, the suturing instrument 100 is configured to be used with an endoscope 708 . A proximal portion 712 of the suturing instrument 100 includes the handle 102 , a carrier drive wire socket 702 attached to a distal end 752 of the handle 102 , and an actuator 112 including a needle deployment button 117 . The proximal portion 712 also includes a scope adapter 706 having a distal end 718 that is connectable to an access port 724 of the endoscope 708 and a proximal end 720 that is connectable to the carrier drive wire socket 702 . The suturing instrument further includes an elongate member 714 that includes a carrier drive wire 710 , which can be formed from, for example, stainless steel or a nickel-titanium alloy, covered by a flexible sheath 704 . The sheath 704 is coupled to a distal portion 716 . The carrier drive wire 710 is connectable to the needle carrier for moving a needle from the distal portion in accordance with any of the embodiments disclosed herein. Also, the distal portion 716 can be stationary, pivoting, or rotatable in accordance with any of the embodiments disclosed herein. In operation, the elongate member 714 is fed into a distal end 722 , through a working channel 726 , and out of an access port 724 of the endoscope 708 . The distal end 718 of the adapter 706 is coupled to the access port 724 of the endoscope 708 and the carrier drive wire 710 is fed through the adapter 706 . The carrier drive wire 710 is then coupled the carrier drive wire socket 702 and the proximal portion 712 of the suturing instrument 100 is secured to the proximal end 720 of the adapter 706 . The endoscope 708 can then be inserted into a patient. The adapter 706 can include any standard or custom fittings necessary to couple to the access port 724 and the proximal portion 712 of the suturing instrument 100 . For example, the adapter 706 can include a luer fitting or a treaded fitting to couple to the endoscope 708 . In one embodiment, the sheath 704 is fixedly coupled to the distal portion 716 , and the distal portion 716 can be rotated by rotating the flexible sheath 704 , using, for example, a rotation controller 760 disposed in the scope adapter 706 . In another embodiment, the handle 102 of the suturing instrument 100 includes two subassemblies. The subassemblies include a thumb-button/finger grasper assembly and a thumb-button/scope assembly. Other embodiments incorporating the concepts disclosed herein may be used without departing from the spirit and scope of the invention. The described embodiments are to be considered in all respects as only illustrative and not restrictive. Therefore, it is intended that the scope of the invention be only limited by the following claims.

Suturing instruments in accordance with the invention are dimensioned and configured to apply sutures to approximate, ligate, or fixate tissue in, for example, open, mini-incision, trans-vaginal, laparoscopic, or endoscopic surgical procedures. In some embodiments, the suturing instruments include a distal portion that is deflectably and/or pivotally coupled to the remainder of the instrument for improved maneuverability and functionality during surgery. In other embodiments, the suturing instruments are capable of housing multiple needle and suture assemblies and/or reloading the needle and suture assembly without removing the instrument from the surgical site.

[0001] This is a Rule 53b Divisional Application of U.S. Ser. No. 10/194,687 filed Jul. 24, 2002 which is a Rule 53b Divisional Application of U.S. Ser. No. 09/583,168 filed May 30, 2000, which is a Rule 53b Continuation Application of U.S. Ser. No. 08/283,165 filed Aug. 3, 1994 which is abandoned, which is a Rule 62 Continuation Application of U.S. Ser. No. 07/671,929 filed Mar. 20, 1991 which is abandoned. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to a data processing apparatus provided with a display device. [0004] 2. Description of the Prior Art [0005] Among compact and lightweight microcomputers, portable type computers powered by batteries are now used extensively. Particularly, one of them known as a note-size computer is lighter in weight and smaller in size, yet provides equal capabilities to those of a desktop or laptop computer. The note-size computer powered by batteries is handy for use in a place where a power supply facility is rarely available, e.g. a meeting room or a lecture hall. [0006] However, the disadvantage of such handy use is that the life of batteries is short and limited. When used to record a business meeting or a college lecture, the service duration of such a note-size computer with fully charged batteries is preferably 10 hours nonstop; more preferably, 20 to 30 hours. If possible, more than 100 hours—a standard of hand calculators—is most desired. [0007] So far, the service operation of a commercially available note-size computer lasts 2 to 3 hours at best. This results in battery runout in the middle of a meeting or college lecture causing an interruption during input work. As a result, troublesome replacement of batteries with new ones will be needed at considerable frequency. [0008] Such a drawback of the note-size computer tends to offset the portability in spite of its light weight and compactness. [0009] It is understood that known pocket-type portable data processing apparatuses including hand calculators and electronic notebooks are much slower in processing speeds than common microcomputers and thus, exhibit less power requirements. They are capable of servicing for years with the use of a common primary cell(s) of which life will thus be no matter of concern. The note-size computer, however, has a processing speed as high as that of a desktop computer and consumes a considerable amount of electric energy-namely, 10 to 1000 times the power consumption of any pocket-type portable data processing apparatus. Even with the application of up-to-date high quality rechargeable batteries, the serving period will be 2 to 3 hours at maximum. This is far from a desired duration demanded by the users. For the purpose of compensating the short life of batteries, a number of techniques for energy saving have been developed and some are now in practical use. [0010] The most well known technique will now be explained. [0011] A “resume” function is widely used in a common note-size computer. It works in a manner that when no input action continues for a given period of time, the data needed for restarting the computer with corresponding information is saved in a nonvolatile IC memory and then, a CPU and a display are systematically turned off. For restart, a power switch is closed and the data stored in the IC memory is instantly retrieved for display of the preceding data provided before disconnection of the power supply. This technique is effective for extension of the battery servicing time and suitable in practical use. [0012] However, a specified duration, e.g. 5 minutes, of no key entry results in de-energization of the entire system of the computer and thus, disappearance of display data. Accordingly, the operator loses information and his input action is interrupted. For reviewing the display data or continuing the input action, the power switch has to be turned on each time. This procedure is a nuisance for the operator. The resume technique is advantageous in saving energy of battery power but very disadvantageous in operability of the note-size computer. [0013] More specifically, the foregoing technique incorporates as a means for energy saving a system which de-energizes all the components including a processing circuit and a display circuit. The operator is thus requested to turn on the power switch of the computer at considerable frequencies during intermittent data input action because each no data entry duration of a given length triggers automatic disconnection of the switch. In particular, the data input operation with a note-size computer is commonly intermittent and thus, the foregoing disadvantage will be much emphasized. SUMMARY OF THE INVENTION [0014] It is an object of the present invention to provide an improved data processing apparatus capable of substantially reducing power consumption while performing required data processing operations. [0015] A data processing apparatus according to the present invention comprises: a data input unit for input of external data; a first processing unit for processing the data inputted through the data input unit; a second processing unit for processing the data inputted through the data input unit and/or an output data of the first processing unit; and a display unit for displaying an output data of the first and/or second processing units, wherein the display unit has a memory function for maintaining a display state without being energized, and the first processing unit has a means for actuating the second processing unit according to a timing or a kind of the input data. [0016] For example, when no data entry continues, the second processing unit or the display unit is inactivated or decreased in clock rate thus diminishing power consumption. Also, the present invention allows the display of data to remain intact. Upon occurrence an input data, the first processing unit activates the second processing unit to process the data. Thus, the operator can prosecute his job without knowledge of an interrupted de-energization. As a result, an appreciable degree of energy saving is guaranteed without affecting the operability and thus, the service life of batteries will largely be increased. [0017] In another aspect, the first processing unit may activate the second processing unit according to the kind of the input data. When the input data is such a data that requires a processing in the second processing unit, the first processing unit activates the second processing unit. The second processing unit, after completing a required operation or processing, may enter an inactive state by itself or may be forced into the inactive state by the first processing unit. Thus, the power consumption will be reduced to a considerable rate without affecting the operability. BRIEF DESCRIPTION OF THE DRAWINGS [0018] [0018]FIG. 1 is a block diagram of a data processing apparatus showing a first embodiment of the present invention; [0019] [0019]FIG. 2 is a timing chart; [0020] [0020]FIG. 3 is a view showing the arrangement of a display unit; [0021] [0021]FIG. 4 is a cross sectional view explaining the operating principle of the display unit; [0022] FIGS. 5 ( a ) and 5 ( b ) are views showing displayed images on the display unit; [0023] [0023]FIG. 6 is a flow chart; [0024] [0024]FIG. 7- a is a block diagram showing an arrangement of components; [0025] [0025]FIG. 7- b is a block diagram showing another arrangement; [0026] [0026]FIG. 7- c is a block diagram showing a further arrangement; [0027] [0027]FIG. 7- d is a flow chart; [0028] FIGS. 8 ( a ) through 8 ( f ) illustrate the operating principle of a reflective device with the use of different reflecting plates; [0029] [0029]FIG. 9 is a block diagram showing a second embodiment of the present invention; [0030] [0030]FIG. 10- a is a block diagram associated with a first processing unit; [0031] [0031]FIG. 10- b is a block diagram associated with a second processing unit; [0032] FIGS. 11 - a and 11 - b are flow charts; [0033] [0033]FIG. 12 is a timing chart; [0034] [0034]FIG. 13 is a view explaining the representation of a cursor; [0035] [0035]FIG. 14 is a view showing a sequence of translation procedures; [0036] [0036]FIG. 15 is a view explaining data insertion; [0037] [0037]FIG. 16 is a view explaining a copy mode; [0038] [0038]FIG. 17 is a block diagram showing a modification of the second embodiment; [0039] [0039]FIG. 18 is a block diagram showing a third embodiment of the present invention; [0040] [0040]FIG. 19 is a flow chart; [0041] [0041]FIG. 20 is a block diagram showing a fourth embodiment of the present invention; [0042] [0042]FIG. 21 is a timing chart of the fourth embodiment; [0043] [0043]FIG. 22 is a block diagram showing a fifth embodiment of the present invention; [0044] [0044]FIG. 23 is a timing chart of the fifth embodiment; [0045] [0045]FIG. 24 is a block diagram showing a data input unit; and [0046] [0046]FIG. 25 is a block diagram showing a combination of the first and second processing units. DESCRIPTION OF THE PREFERRED EMBODIMENTS [0047] Preferred embodiments of the present invention will be described referring to the accompanying drawings. [0048] Embodiment 1 [0049] [0049]FIG. 1 is a block diagram of a data processing apparatus showing a first embodiment of the present invention. [0050] The data processing apparatus comprises a data input unit 3 , a first processing block 1 , a second processing block 98 , and a display block 99 . [0051] In operation, a data input which is fed to the data input unit 3 of the data processing apparatus by means of key entry with a key-board or communications interface is transferred to the first processing block 1 in which a first processor 4 examines which key in key entry is pressed or what sorts of data are input from the outside and determines the subsequent procedure according to the information from a first memory 5 . [0052] If no input is supplied to the data input unit 3 throughout a given period of time as shown in FIG. 2- a and also, the action of a second processor 7 has been completed, the feeding of clock signals to the second processor 7 and a display circuit 8 is halted by an interruption controller 6 and/or a process of energy saving is systematically executed. [0053] The energy saving process will now be described referring to FIG. 2. [0054] As shown in FIG. 2- a , a data input entered at t1 using an n-th key of the key-board is transferred from the data input unit 3 to the first processor 4 . [0055] The first processor 4 when examining the data input and determining that further processing at the second processor 7 is needed delivers a start instruction via the interruption controller 6 and a start instruction line 80 to the second processor 7 which thus commences receiving the data input from the first processor 4 . The second processor 7 starts processing the data input when t=t3 as shown in FIG. 2- c and upon finishing, sends an end signal to the first processor 4 . In turn, either the first processor 4 or the interruption controller 6 delivers a stop instruction to the second processor 4 via the startup instruction line 80 . Accordingly, the second processor 4 transfers finally processed data from its RAM memory or register to the second memory for temporary storage and then, stops processing action when t=t5 as shown in FIG. 2- c or enters into an energy saving mode where a consuming power is sharply attenuated. After t5 where the actuation of the second processor 7 is ceased, the data remains held in the second memory 9 due to its nonvolatile properties or due to the action of a back-up battery. If display change is needed, the second processor 4 sends a display change signal to the first processor 4 . The first processor 4 then delivers a display start instruction via a display start instruction line 81 to the display circuit 8 for starting actuation. When t=t4 as shown in FIG. 2- d , the command signal is transmitted to the display circuit 8 which in turn retrieves the data of a previous display text from a video memory 82 or the second memory 9 and displays a new image corresponding to the display change signal and data from the second processor 7 . When t=t6, the display circuit 8 sends its own instruction or an end signal via the interruption controller 6 to the first processor 4 and upon receiving an instruction from the first processor 4 , stops or diminishes clock generation to enter a display energy saving mode. Thereafter, the power consumption of the display circuit 8 will largely be declined as illustrated after t6 in FIG. 2- d. [0056] After t6, the display circuit 8 stays fully or nearly inactivated but a display 2 which is substantially consisted of memory retainable devices, e.g. ferroelectric liquid crystal devices, continues to hold the display image. The arrangement of the display 2 will now be described. The display 2 , e.g. a simple matrix type liquid crystal display, contains a matrix of electrodes in which horizontal drive lines 13 and vertical drive lines 14 coupled to a horizontal driver 11 and a vertical driver 12 respectively intersect each other, as best shown in FIG. 3. FIG. 4 illustrates a pixel of the display 2 in action with a voltage being applied. [0057] In each pixel, a ferroelectric liquid crystal 17 is energized by the two, horizontal and vertical lines 13 , 14 which serve as electrodes and are provided on glass plates 15 and 16 respectively. [0058] More particularly, FIG. 4- a shows a state where light is transmitted through. When a signal is given, the ferroelectric liquid crystal 17 changes its crystalline orientation and acts as a polarizer in which an angle of polarization is altered, thus allowing the light to pass through. [0059] When a voltage is applied in the reverse direction, the ferroelectric liquid crystal 17 causes the angle of polarization to turn 90 degrees and inhibits the passage of light with polarization effects, as shown in FIG. 4- b . The ferroelectric liquid crystal 17 also has a memory retainable effect as being capable of remaining unchanged in the crystalline orientation after the supply of voltage is stopped, as shown in FIG. 4- c . Accordingly, throughout a duration from t=t6 to t=t14, explained later, the display remains intact without any operation of the display circuit 8 . While the energy saving mode is involved after t6, both the data input unit 3 and the first processor 4 are only in action. [0060] The first processor 4 performs only conversion of key entry to letter code or the like. In general, the key entry is conducted by a human operator and executed some tens times in a second at best. The speed of data entry by a human operator is 100 times or more slower than the processing speed of any microcomputer. Hence, the processing speed of the first processor 4 may be as low as that of a known hand calculator and the power consumption will be decreased to hundredths or thousandths of one watt as compared with that of a main CPU in a desktop computer. As shown in FIG. 2- b , the first processor 4 continues operating while a power switch 20 of the data processing unit 1 is closed. However, it consumes a lesser amount of energy and thus, the power consumption of the apparatus will be low. [0061] When n+1-th key entry is made at t11, the first processor 4 examines the data of the entry at t12 and if necessary, delivers a start instruction via the interruption controller 6 or directly to the second processor 7 for actuation. Upon receiving the start instruction, the second processor 7 starts processing again with the use of clock signals so that the data stored in the second memory 9 , i.e. data at a previous stop when t=t5, such as memory data, register information, or display data, is read out and the CPU environment when t=t5 can fully be restored. When t=t13, the data in the first processor 4 is transferred to the second processor 7 for reprocessing. The second processor 7 is arranged to operate at high speeds and its power consumption is as high as that of a desk-top computer. If the second processor 7 is continuously activated, the life of batteries will be shortened as well as in a known note computer. The present invention however provides a series of energy saving mode actions during the operation, whereby the energy consumption will be minimized. [0062] The energy saving mode is advantageous. For example, the duration required for processing the data of a word processing software is commonly less than 1 ms while the key entry by a human operator takes several tens of milliseconds at maximum. Hence, although the peak of energy consumption during a period from t13 to t15 is fairly high in the second processor 7 as shown in FIG. 2- c , the average is not more than a tenth or a hundredth of the peak value. It is now understood that the energy saving mode allows lower power consumption. [0063] When t=t14, the second processor 7 sends a desired portion of the display data to the display 2 . Before t14, the display 2 continues to display the text altered at t6 due to the memory effects of the ferroelectric liquid crystal 17 while the display circuit 8 remains inactivated. The desired data given through the key entry at t11 is written at t14 for regional replacement. The replacement of one to several lines of display text is executed by means of voltage application to corresponding numbers of the horizontal and vertical drive lines 13 and 14 . This procedure requires a shorter period of processing time and thus, consumes a lesser amount of energy as compared with replacement of the entire display text. [0064] The second processor 7 then stops operation when t=t15 and enters into the energy saving mode again as shown in FIG. 2- c. [0065] At the moment when the operation of the second processor 7 has been finished before t5 or when a stop instruction from the first processor 4 is received, the second processor 7 saves the latest data in the second memory 9 . [0066] When t=t14, the second processor 7 stops operation or diminishes an operating speed and enters into the energy saving mode. [0067] When the input data is fed at short intervals, e.g. at t21, t31, t41, and t51, through a series of key entry actions or from a communications port, the second processor 7 shifts to the energy saving mode at t23, t33, and t43 as shown in FIG. 2- c . If the first processor 4 detects that the interval between data inputs is shorter than a predetermined time, it delivers an energy saving mode stop instruction to the second processor 7 which thus remains activated without forced de-energization and no longer enters into the energy saving mode. The energy saving mode is called back only when the interval between two data inputs becomes sufficiently long. [0068] Also, when the first processor 4 detects that the key entry is absent during a given length of time, it actuates to disconnect the power supply to primary components including the first processor 4 for shift to a power supply stop mode. The memory data is being saved by the back-up battery while the power supply is fully disconnected. [0069] Before disconnection of the power supply, the first processor 4 however sends a power supply stop display instruction directly or via the second processor 7 to the display circuit 8 for display of an “OFF” sign 21 shown in FIG. 5- b and then, enters into the power supply stop mode. The OFF sign 21 remains displayed due to the memory effects of the display 2 after the power supply is disconnected, thus allowing the operator to distinguish the power supply stop mode from the energy saving mode. [0070] In the energy saving mode, the operation can be started again by key entry action and thus, the operator will perceive no interruption in the processing action. [0071] In the power supply stop mode, the OFF sign 21 is displayed and the operator can restart the operation in succession with the previous data retrieved from the second memory 9 by the second processor 9 when the power switch 20 is turned on. This procedure is similar to that in the conventional “resume” mode. [0072] The foregoing operation will now be described in more detail referring to a flow chart of FIG. 6. When the power switch 20 is turned on at Step 101 , the first processor 4 starts activating at Step 102 . The input data given by key entry is transferred from the data input unit 3 to the first processor 4 at Step 103 . At Step 104 , it is examined whether the duration of no-data entry lasts for a predetermined time or not. If the no-data entry duration t is greater than the predetermined time, the procedure moves to Step 105 where the actuation of the second processor 7 is examined. If the second processor 7 is in action, the procedure moves back to Step 103 . If not, the entire apparatus is de-energized, at Step 106 , and stops actuating at Step 107 before restarting with Step 101 where the power supply switch 20 is closed. [0073] If the no-data entry duration t is greater than the predetermined time, but is as short as a few minutes, the procedure is shifted from Step 104 to Step 108 . When the processing frequency in the first and second processors 4 and 7 is low, the procedure moves from Step 108 to Step 109 where a back light is turned off for energy saving. [0074] If the no-data entry duration t is not greater than the predetermined time, the operation in the first processor 4 is prosecuted at Step 110 . Also, it is examined at Step 110 a whether the data of text is kept displayed throughout a considerable length of time or not. If too long, refreshing action of the data display is executed at Step 110 b for prevention of an image burn on the screen. At Step 110 c , the processing frequency in the second processor 7 is examined and if it is high, the second processor 7 is kept in action at Step 110 d . If the processing frequency is low, the procedure moves to Step 111 . When it is determined at Step 111 that no further processing in the second processor 7 is needed, the procedure returns to Step 103 . [0075] When further processing in the second processor 7 is required, the procedure moves from Step 111 to Step 112 a where the actuation of the second processor 7 is examined. If the second processor 7 is not in action, a start instruction is fed at Step 112 b to the second processor 7 which is in turn activated at Step 113 by the first processor 4 and the interruption controller 6 . The second processor 7 then starts processing action at Step 114 . If it is determined at Step 115 that a change in the text of display is needed, the procedure moves to Step 116 a where a display change instruction is supplied to both the interruption controller 6 and the first processor 4 . Then, the interruption controller 6 delivers a display energizing instruction to the display block 99 at Step 116 b . The display circuit 8 is activated at Step 116 c and the display change on the display 2 including the replacement of a regional data with a desired data is carried out at Step 117 . After the display change is checked at Step 118 , a display change completion signal is sent to the first processor 4 at Step 117 a . When the display change completion signal is accepted at Step 117 b , the display 2 is turned off at Step 119 . [0076] If no change in the display text is needed, the procedure moves from Step 115 to Step 120 where the completion of the processing in the second processor 7 is examined. If yes, a processing completion signal is released at Step 120 a . As a result, the second processor 7 stops operation at Step 121 upon receiving a stop signal produced at Step 120 b and the procedure returns back to Step 103 . [0077] FIGS. 7 - a and 7 - b are block diagrams of a note-size computer according to the first embodiment of the present invention. [0078] As shown in FIG. 7- a , a data input block 97 comprises a keyboard 201 , a communication port 51 with RS232C, and a floppy disk controller 202 . Also, a hard disk unit 203 is provided separately. A first processing block 1 is mainly consisted of a first processor 4 . A second processing block 98 contains a second processor 7 which is a CPU arranged for shift to and back from the energy saving mode upon stopping and feeding of a clock signal respectively and is coupled to a bus line 210 . Also, a ROM 204 for start action, a second memory 9 of DRAM, and a backup RAM 205 which is an SRAM for storage of individual data of returning from the resume mode are coupled to the bus line 210 . Both ends of the bus line 210 are connected to the first processor 4 and a display block 99 respectively. The display block 99 has a graphic controller 206 and a liquid crystal controller driver 207 arranged in a display circuit. There are also provided a video RAM 209 and a liquid crystal display 208 . For energy saving operation, corresponding components only in the arrangement are activated while the remaining components are de-energized. This energy saving technique is illustrated in more detail in Table 1. In general, input operation for e.g. word processing involves an intermittent action of keyboard entry. Hence, the power supply is connected to every component except the communications I/O unit. While a clock signal is fed to the first processing block 1 , no clock signals are supplied to the second processing block 98 and the display block 99 . Power is thus consumed only in the first processing block 1 . If necessary, the second block 98 and/or the display block 99 are activated within a short period of time. If more frequent operations are needed, the second processing block 98 is kept activated for acceleration of processing speeds. [0079] When the key entry is absent for a given time, the second processing block 98 is disconnected and simultaneously, its processing data is stored in a backup memory for retrieval in response to the next key entry. [0080] [0080]FIG. 7- b is similar to FIG. 7- a , except that the first processor 4 having a lower clock frequency is used as a “monitor” for the total system and the processing will be executed by the second processor 7 having a higher clock frequency. The first processor 4 is adapted for operating an event processing method by which the second processor 7 is activated for processing action corresponding to data of the keyboard entry. The second processor 7 stops operation for the purpose of energy saving when the processing action is finished and remains inactivated until another key entry commences. The display block 99 starts operating in response to a display signal from the second processor 7 and stops automatically after completion of display. This procedure can be executed with a common operating system similar to any known operating system, thus ensuring high software compatibility. For example, MS-DOS is designed to run with the use of one complete CPU. Hence, the energy saving effect will hardly be expected during operation with conventional application software programs. It is then a good idea that a specific operating system and a corresponding word processing software which are installed in two CPUs are provided in addition to the conventional operating system. Accordingly, a word processing job can be performed using the specific software with the operating system of the present invention and thus, the power consumption will be reduced to less than a tenth or hundredth. Also, general purpose software programs can work with the conventional operating system—although the energy saving effect will be diminished. It would be understood that about 80% of the job on a note-size computer is word processing and the foregoing arrangement can contribute to the energy saving. [0081] [0081]FIG. 7- c is a block diagram of another example according to the first embodiment and FIG. 7- d is a flow chart showing a procedure with the use of a conventional operating system such as MS-DOS. The second processor 7 is a CPU capable of holding data from its register and internal RAM during actuation of no clock or de-energization. When key entry is made at Step 251 , a keyboard code signal from the keyboard 201 is transferred by the first processor 4 to a start device 221 which remains activated, at Step 252 . At Step 253 , the start device 221 delivers a clock signal to a main processor 222 which is de-energized. Both of the register 223 and the internal RAM 224 are coupled to a backup source and thus, start operating upon receipt of the clock signal. At Step 254 , the main processor 222 starts the program which has been on stand-by for key entry. The program is then processed for e.g. word processing according to data of the key entry, at Step 255 . At Step 257 , a display instruction is released for replacement of display text if required at Step 256 . At Step 258 , the graphic controller 206 is activated. The data in the video RAM 209 is thus rewritten at Step 259 . After the liquid crystal controller driver 207 is activated at Step 261 , a desired change in the display text is made on the liquid crystal display 208 formed of ferroelectric liquid crystal. Then, the video RAM 209 is backup energized at Step 262 and the display block 99 is de-energized, at Step 263 , thus entering into the energy saving mode. When the processing in the second processor 7 is completed at Step 270 , the program stops and moves into a “keyboard entry stand-by” stage at Step 271 . At Step 272 , the data required for re-actuation of the register 223 and the internal RAM 234 is saved and the second memory 9 is backup energized before a clock in the CPU is stopped. Then, the second processor 7 stops operation, at Step 273 , thus entering into the energy saving mode. As the start device 221 remains activated, the second processor 7 stays on stand-by for input through keyboard entry at Step 251 or from the communications port 5 . As understood, the start device 221 only is kept activated in the second processing block 98 . The CPU shown in FIG. 7- c provides backup of registers with its clock unactuated and ensures instant return to operation upon actuation of the clock. As a single unit of the CPU is commonly activated, a conventional operating system can be used with equal success. Also, existing software programs including word processing programs can be processed with less assignment and thus, private data stock will be permitted for optimum use. Consequently, it would be apparent that this method is eligible. In addition, the consumption of electric energy will be much decreased using a technique of direct control of the first processor 1 on display text change which will be described later with a second embodiment of the present invention. As understood, the resume mode allows most components to remain de-energized when no keyboard entry lasts for a long time. [0082] As a ferroelectric liquid crystal material has a memory effect, permanent memory results known as protracted metastable phenomenon will appear when the same text is displayed for a longer time. For prevention of such phenomenon, a display change instruction is given to the first processor 4 and the power switch 20 upon detection with the timer 22 that the display duration exceeds a predetermined time in the energy saving mode or power supply stop mode. Accordingly, the display circuit 8 actuates the display 2 to change the whole or a part of the display text, whereby permanent memory drawbacks will be eliminated. [0083] If it is happened that the persistence of such permanent memory effects allows no change in the display text on the display 2 , the crystalline orientation of liquid crystal is realigned by heating up the display 2 with a heater 24 triggered by a display reset switch 23 . Then, arbitrary change in the display text on the display 2 will be possible. [0084] Energy saving can be promoted by stopping the clock in the second processor 7 during the energy saving mode. When more or full energy saving is wanted, the power supply to the second processor 7 or the display circuit 8 is disconnected by the interruption controller 6 . [0085] As understood, the power supply stop mode requires a minimum of power consumption for backup of the second memory 9 . [0086] As shown in FIG. 1, the back light 25 is turned off when the power source is a battery and a reflective device 27 is activated by a reflection circuit 26 for display with a reflection mode. [0087] The reflective device 27 is composed of a film of ferroelectric liquid crystal which provides a transparent mode for transmission of light, as shown in FIG. 8- a , and an opaque mode for reflection as shown in FIG. 8- b , for alternative action. Incoming light 32 is reflected on the reflective device 27 and runs back as reflected light 33 . At this time, polarization is also effected by the polarizers in the display 2 and the reflective device 27 , whereby the number of components will be reduced. Also, a film-form electrochromic display device may be used for providing a transmission mode and a white diffusion screen mode in which it appears like a sheet of white paper. [0088] The reflective device 27 may be of fixed type, as shown in FIGS. 8 - c and 8 - d , comprising a light transmitting layer composed of low refraction transmitting regions 28 and high refraction transmitting regions 29 and a reflecting layer 31 having apertures 30 therein. [0089] As shown in FIG. 8- c , light emitted from the back light 25 enters the high refraction transmitting regions 29 where it is fully reflected on the interface between the high and low refraction transmitting regions 29 , 28 and passes across the apertures 31 to a polarizer plate 35 . The polarized light is then transmitted to a liquid crystal layer 17 for producing optical display with outwardly emitted light. [0090] During the reflection mode in battery operation, outside light 32 passes the liquid crystal layer 17 and is reflected by the reflecting layer 31 formed by vapor deposition of aluminum and reflected light 33 runs across the liquid crystal layer 17 again for providing optical display. [0091] The reflective device 27 requires no external drive circuit, thus contributing to the simple arrangement of a total system. It is known that such a combination of high and low refraction transmitting regions is easily fabricated by a fused salt immersion method which is commonly used for making refraction distributed lenses. [0092] Although such a transmission/reflection combination type liquid crystal display is disadvantageous in the quality of a display image as compared with a transmission or reflection speciality type liquid crystal display, the foregoing switching between transmission and reflection allows display of as good an image as of the speciality type display in both the transmission and reflection modes. This technique is thus suited to two-source, battery and AC application. [0093] When the external power source is connected, the back light 25 is lit upon receiving an instruction from the first processor 4 which also delivers a transmission instruction to the reflection circuit 26 and thus, the reflective device 27 becomes transparent simultaneously. Accordingly, transmitting light can illuminate the display as shown in FIG. 8- a. [0094] When the battery is connected, the first processor 4 delivers a reflection signal to the reflection circuit 26 and the reflective device 27 becomes opaque to cause reflection and diffusion. As a result, the display is made by reflected outside light as shown in FIG. 8- b while an amount of electric energy required for actuation of the back light 25 is saved. [0095] Also, the same result as shown in FIGS. 8 - c and 8 - d may be provided with the use of a transmitting reflective plate 34 which is formed of a metal plate, e.g. of aluminum, having a multiplicity of tapered round apertures therein, as illustrated in FIGS. 8 - e and 8 - f. [0096] As set forth above, the CPU in this arrangement provides intermittent actuation in response to the intermittent key entry and the average power consumption of the apparatus will be declined to an appreciable rate. [0097] Also, the text remains on display during the operation and thus, the operator can perceive no sign of abnormality when the processing unit is inactivated. More particularly, a great degree of energy saving will be ensured without affecting the operability. [0098] More particularly, each key entry action takes several tens of milliseconds while the average of CPU processing durations in word processing is about tens to hundreds of microseconds. Hence, the CPU is activated {fraction (1/100)} to {fraction (1/1000)} of the key entry action time for accomplishing the task and its energy consumption will thus be reduced in proportion. However, while the energy consumption of the CPU is reduced to {fraction (1/1000)}, {fraction (1/10)} to {fraction (1/20)} of the overall consumption remains intact because the display unit consumes about 10 to 20%, namely 0.5 to 1 W, of the entire power requirement. According to the present invention, the display unit employs a memory effect display device provided with e.g. ferroelectric liquid crystal and thus, its power consumption will be minimized through intermittent activation as well as the CPU. [0099] As the result, the overall power consumption during mainly key entry operation for e.g. word processing will be reduced to {fraction (1/100)} to {fraction (1/1000)}. [0100] Embodiment 2 [0101] [0101]FIG. 9 is a block diagram showing a second embodiment of the present invention. [0102] In the second embodiment, the first processor 4 is improved in the operational capability and the second processor 7 of which energy requirement is relatively great is reduced in the frequency of actuation so that energy saving can be encouraged. [0103] As shown in FIG. 9, the arrangement of the second embodiment is distinguished from that of the first embodiment by having a signal line 97 for transmission of a display instruction signal from the first processing block 1 to the display block 99 . In operation, the first processor 4 of the first processing block 1 delivers a display change signal to the display circuit 8 of the display block 99 for change of the display text on the display 2 . As understood, the second processor 7 delivers such a display change signal to the display circuit 8 according to the first embodiment. [0104] [0104]FIG. 10- a is a block diagram showing in more detail the connection of the first processor 4 , in which the first memory 5 comprises a first font ROM 40 for storage of dot patterns of alphabet and Japanese character fonts or the like in a ROM, an image memory 41 , and a general memory 42 . [0105] As shown in FIG. 10 b , the second memory 9 may contain a second font ROM 43 which serves as a font memory. [0106] In operation, a series of simple actions for display text change can be executed using the first processor 4 . Character codes are produced in response to the key entry and font patterns corresponding to the character codes are read from the first 40 or second font memory 43 for display on the display 2 after passing the display circuit 8 . The second memory 9 may also contain a second general memory 44 . [0107] During input of a series of data characters which requires no large scale of processing, the first processor 4 having less energy requirement is actuated for operation of the display text change. If large scale of processing is needed, the second processor 7 is then utilized. Accordingly, the frequency of actuation of the second processor 7 is minimized and energy saving will be guaranteed. Also, as shown in FIG. 11, the memory size of the first memory 5 can be decreased because of retrieval of font patterns from the second font ROM 43 of the second memory 9 . [0108] The operation according to the second embodiment will now be described in more detail referring to flow charts of FIGS. 11 - a and 11 - b . FIG. 11- a is substantially similar to FIG. 6 which shows a flow chart in the first embodiment. [0109] A difference is that as the first processor 4 directly actuates the display circuit 8 , a step 130 and a display flow chart 131 are added. When the first processor 4 judges that the display is to be changed in Step 130 and that a desired data for replacement in the display text is simple enough to be processed by the first processor 4 at Step 111 , the procedure moves to the display flow chart 131 . The display flow chart 131 will now be described briefly. It starts with Step 132 where the display block 99 is activated. At Step 133 , the display text is changed and the change is examined at Step 133 . After the confirmation of the completion of the text change at Step 134 , the display block 99 is de-energized at Step 135 and the procedure returns back to Step 103 for stand-by for succeeding data input. FIG. 11- b illustrates the step 133 in more detail. After the display block 99 is activated, at Step 132 , by a start instruction from the first processing block 1 , the movement of a cursor with no restriction is examined at Step 140 . If yes, data input throughout the cursor movement is executed at Step 141 . If not, it is then examined whether the desired input area on the display 2 is occupied by existing data or not at Step 142 . This procedure can be carried out by reading the data in the image memory 41 with the first processor 4 . If no, partial text replacement with desired data is executed at Step 143 . If yes, the procedure moves to Step 144 where the existing data in the input area of the display block 99 is checked using the image memory 41 and examined whether it is necessarily associated or not with the desired data to be input. If no, overwriting of the desired data is executed at Step 143 . If yes, the existing data is retrieved from the image memory 41 or read from the second font ROM 9 and coupled with the desired data for composition, at Step 145 . At Step 146 , it is examined whether a black/white inversion mode is involved or not. If yes, the data is displayed in reverse color at Step 147 . If no, the text change with the composite data is carried out at Step 148 . Then, the completion of the text change is confirmed at Step 134 and the display block 99 is turned off at Step 99 . [0110] For a more particular explanation, the processing action of corresponding components when the key entry is made is illustrated in FIG. 12. When the key entry with “I” is conducted at t1 as shown in FIG. 12- e , the first processor 4 shifts input data into a letter “I” code, reads a font pattern of the letter code from the first font ROM 40 shown in FIG. 10, and actuates the display circuit for display of the letter “I” on the display 2 . With the memory effect display having ferroelectric crystal liquid, partial replacement in a character can be made. The partial replacement is feasible in two different manners; one for change dot by dot and the other for change of a vertical or horizontal line of dots at once. The dot-by-dot change is executed with less energy requirement but at a higher voltage, thus resulting in high cost. The line change has to be done in the group of dots at once even when one dot only is replaced but at relatively lower voltages. Both manners in this embodiment will now be explained. [0111] When the horizontal and vertical drivers 11 , 12 shown in FIG. 3 accept higher voltages, it is possible to fill the dots forming the letter “I” one by one. Accordingly, the letter “I” can be displayed by having a font data of a corresponding character pattern supplied from the first processor 4 . However, ICs accepting such a high voltage are costly. It is thus desired for cost saving that the operating voltage is low. It is now understood that every data processing apparatus is preferably arranged, in view of capability of up-to-date semiconductors, for providing line-by-line text change operation. [0112] It is also necessary that the first memory 5 of the first processor 4 carries at least data of one text line. [0113] For Japanese characters, the one text line data is equal to 640×24 dots. The writing of the letter “I” thus involves replacement of 24 of 640-dot lines. [0114] In operation, the previous data of a target line is retrieved from the image memory 41 of the first memory 5 and also, the pattern data of the letter “I” is read from the first font ROM 40 . Then, the two data are combined together to a composite data which is then fed to the display circuit 8 for rewriting of one text line on the display 2 . Simultaneously, the same data is stored into the image memory 41 . The input of “I” is now completed. [0115] None of the first font ROM 40 and the image memory 41 is needed when the second font ROM 43 is employed for the same operation, which is capable of processing coded data. In particular, the same text line can be expressed with about 40 of 2-byte characters and thus, 40×2=80 bytes per line. Therefore, the first memory 5 may carry coded data of the entire screen image. [0116] During the processing of data input “I” in either of the two foregoing manners, the second processor 7 provides no processing action as shown in FIG. 12- c. [0117] Similarly, a series of key inputs are prosecuted by the first processor 4 , “space” at t2, “L” at t3, “i” at t4, “v” at t5, and “e” at t6. Although the first processor 4 is much slower in the processing speed than the second processor 7 , the replacement of one text line on display can be pursued at an acceptable speed with less energy consumption. [0118] As shown in FIG. 12, t7 represents the key input of an instruction for processing a large amount of data, e.g. spelling check in word processing, translation from Japanese to English, conversion of Japanese characters into Chinese characters, or calculation of chart data. [0119] When the first processor 4 determines that the processing at the second processor 7 is needed, the second processor 7 is turned on at t71. The start-up of the second processor 7 is the same as of Embodiment 1. As shown in FIG. 12- c , the second processor 7 upon being activated at t71 returns to the original state prior to interruption and starts processing the data of text lines fed from the first processor 4 . As the processing is prosecuted, each character of changed text is displayed on the display 2 through the display circuit 8 as shown at t72 in FIG. 12- d. [0120] This procedure will now be explained in the form of data entry for translation from Japanese to English. After the letter k is input at t1, as shown in FIG. 12- f , and displayed on the screen, as shown in FIG. 12- h . Then, the letter a is input at t2 and the display reads “ka” as shown in FIG. 12- h. [0121] By then, the second processor 7 remains inactivated as shown in FIG. 12- c . When a key of translating conversion is pressed at t7, the second processor 7 starts processing at t71. Accordingly, the Japanese paragraph “kareha” is translated to “He is” in English. The resultant data is sent to the display circuit 8 for dot-by-dot replacement for display. [0122] Now, the display reads “He is” as shown in FIG. 12- h . The dot-by-dot character replacement shown in FIG. 12- g requires less electric energy than the text line replacement shown in FIG. 12- d. [0123] For the purpose of saving energy during the movement of the cursor, the black/white inversion or negative mode is used as shown in FIGS. 13 - a and 13 - b . This however increases the power consumption in the line replacement. When a bar between the lines is used for display of the cursor as shown in FIGS. 13 - c and 13 - d , the replacement of the full line is not needed and thus, energy saving will be expected. Also, the speed of processing is increased and the response will speed up during processing with the low speed first processor 4 . This advantage is equally undertaken in the dot-by-dot replacement. [0124] As shown in FIG. 14- a , the movement of the cursor is expressed by the bar. For ease of viewing, the bar may be lit at intervals by means of control with the first processor 4 . When a key data input is given, a corresponding character is displayed in the reverse color as shown in FIG. 14- b . This technique will also reduce the energy consumption at least during the cursor movement. [0125] FIGS. 14 - a to 14 - g illustrate the steps of display corresponding to t1 to t7. FIG. 14- h shows the conversion of the input text. [0126] FIGS. 15 - a to 15 - f shows the insertion of a word during dot-by-dot replacement. It is necessary with the use of the second font ROM 43 in the arrangement shown in FIG. 10 that the data of one text line is saved in the image memory 41 because the first font ROM 40 does not carry all the Chinese characters. When the cursor moves backward as shown in FIGS. 15 - c and 15 - d , the letter n is called back from the image memory 41 . Accordingly, the data prior to insertion can be restored without the use of the second processor 7 or the second front ROM 43 as shown in FIG. 15- d. [0127] FIGS. 16 - a to 16 - g show the copy of a sentence “He is a man”. The procedure from FIG. 16- a to FIG. 16- f can be carried out with the first processor 4 . The step of FIG. 16- g involves an insertion action which is executed by the second processor 7 . [0128] According to the second embodiment, most of the job which is processed by the second processor 7 in the first embodiment is executed by the low power consuming first processor 4 . Thereby, the average energy consumption will be much lower than that of the first embodiment. [0129] The optimum of a job sharing ratio between the first and second processors 4 and 7 may vary depending on particulars of a program for e.g. word processing or chart calculation. Hence, a share of the first processor 4 in operation of a software program can be controlled by adjustment on the program so as to give an optimum balance between the energy consumption and the processing speed. Also, a video memory 82 may be provided in the display block 99 for connection via a connecting line 96 with the first processor 4 . This allows the data prior to replacement to be stored in the video memory 82 and thus, the image memory 41 shown in FIG. 10- a will be eliminated. [0130] Embodiment 3 [0131] [0131]FIG. 18 is a block diagram showing a third embodiment of the present invention. The difference of the third embodiment from the first and second embodiments will now be described. As shown in FIG. 1, the first embodiment has the display start instruction line 81 along which both a start instruction and a stop instruction are transferred from the first processing block 1 to the display block 99 while equal instructions are transferred by the start instruction line 80 from the same to the second processing block 98 . [0132] The third embodiment contains no display start instruction line 81 to the display block 99 as shown in FIG. 18. Also, the start instruction line 80 of the third embodiment allows only a start instruction but not a stop instruction to be transmitted from the first processing block 1 to the second processing block 98 . [0133] The second processor 7 stops itself upon finishing the processing and enters into the energy saving mode. When the second processor 7 determines that the display change is needed, it delivers a display start instruction via a data line 84 to the display block 99 which is then activated. After the display change on the display 2 is completed, the display block 99 stops operation and enters into the display energy saving mode. This procedure will be explained in more detail using a flow chart of FIG. 19. The flow chart is composed of a first processing step group 151 , a second processing step group 152 , and a third processing step group 153 . At first, the difference of this flow chart will be described in respect to the sequence from start to stop of the second processing block 98 . [0134] There is no control flow from the second processing step group 152 of the second processing block 98 to the first processing step group 151 , unlike the flow chart of the first embodiment shown in FIG. 6. More specifically, the first processor 4 delivers, at Step 112 , a start instruction to the second processor 7 which is then activated. This step is equal to that of the first embodiment. However, the second processor 7 is automatically inactivated at Step 121 , as compared with de-energization by an instruction from the first processor 4 in the first embodiment. At Step 103 , the second processor 7 is turned to a data input stand-by state. [0135] The difference will further be described in respect to the sequence from start to stop of the display block 99 . [0136] In the first embodiment, a display start instruction to the display block 99 is given by the second processor 7 after completion of display data processing. According to the third embodiment, the start instruction is delivered by the second processing block 98 to the display block 99 , at Step 115 a shown in FIG. 19. Then, the display block 99 is activated at Step 116 and the display change is conducted at Step 117 . After the display change is examined at Step 118 , the display block 99 stops itself at Step 119 . [0137] As understood, the third embodiment which is similar in the function to the first embodiment provides the self-controlled de-energization of both the second processing block 98 and the display block 99 . [0138] Also, a start instruction to the display block 99 is given by the second processing block 98 . Accordingly, the task of the first processing block 1 is lessened, whereby the overall processing speed will be increased and the arrangement itself will be facilitated. [0139] Embodiment 4 [0140] [0140]FIG. 20 is a block diagram showing a fourth embodiment of the present invention, in which an energy saving manner is disclosed with the use of an input/output port for communications with the outside. A data processing apparatus of the fourth embodiment incorporates an input/output unit 50 mounted in its data input block 97 . The input/output unit 50 contains a communications port 51 and an external interface 52 . In operation, the unit 50 performs actions as shown in a timing chart of FIG. 21 which is similar to the timing chart of key data entry shown in FIG. 12. When a series of inputs from the communications port are introduced at t1 to t74, as shown in FIG. 21- a , the input/output unit 50 delivers corresponding signals to the first processing block 1 . The first processor 4 sends an input data at t1 to the display circuit 8 which in turn actuates, as shown in FIG. 21- d , for display of a data string as illustrated in FIG. 21- e . If an input at t7 is bulky, the second processor 7 is activated at t71 as shown in FIG. 21- c. [0141] The second processor 7 delivers a start instruction at t72 to the display circuit 8 which is then actuated for data replacement on the display 2 . If the input through the communications port is not bulky, it is processed in the first processor 4 or the input/output unit 50 while the second processor 7 remains inactivated. Accordingly, energy saving during the input and output action will be ensured. [0142] Embodiment 5 [0143] [0143]FIG. 22 is a block diagram showing a fifth embodiment of the present invention, in which a solar battery 60 is added as an extra power source. The first processor 4 operates at low speeds thus consuming a small amount of electric energy. Accordingly, the apparatus can be powered by the solar battery 60 . While the action is almost equal to that of the first embodiment, the solar battery however stops power supply when the amount of incident light is decreased considerably. If the supply is stopped, it is shifted to from the source 61 . When no key entry is made throughout a length of time and no power supply from the solar battery 60 is fed, the source stop mode is called for as shown in FIG. 23- b . The first processor 4 saves processing data into the first memory 5 and then, stops operation. Thus, the power consumption will be reduced. When a power supply from the solar battery 60 is fed again at t71 or another key input data is fed from the data input unit 3 , the first processor 4 starts actuating for performance of an equal action from t72. [0144] One example of the start procedure of the first processor 4 will now be described. As shown in FIG. 24, a key input device 62 of the data input unit 3 feeds a voltage from the battery 64 to a hold circuit 63 . The hold circuit 63 upon pressing of a key connects the power source to the first processor 4 for energization. Simultaneously, the key input device 62 transfers a key input data to the first processor 4 and processing will start. [0145] Each key of the key input device 62 may have a couple of switches; one for power supply and the other for data entry. [0146] Accordingly, as the solar battery is equipped, the power consumption will be minimized and the operating life of the apparatus will last much longer. [0147] The solar battery 60 , which becomes inactive when no incoming light falls, may be mounted on the same plane as of the display 2 so that no display is made including text and keyboard when the solar battery 60 is inactivated. [0148] Hence, no particular trouble will arise in practice. In case of word processing in the dark e.g. during projection of slide pictures in a lecture, a key entry action triggers the hold circuit 3 for actuation of the first processor 4 . [0149] As the data processing apparatus of the fifth embodiment provides more energy saving, it may be realized in the form of a note-size microcomputer featuring no battery replacement for years. Also, the first and second processors in any of the first to fifth embodiments may be integrated to a single unit as shown in FIG. 25. [0150] It was found through experiments of simulative calculation conducted by us that the average power consumption during a word processing program was reduced from 5 w of a reference value to as small as several hundredths of a watt when the present invention was associated. This means that a conventional secondary cell lasts hundreds of hours and a primary cell, e.g. a highly efficient lithium cell, lasts more than 1000 hours. In other words, a note-size computer will be available which lasts, like a pocket calculator, over one year in use of 5-hour a day without replacement of batteries. As understood, intensive attempts at higher-speed operation and more-pixel display are concurrently being prosecuted and also, troublesome recharging of rechargeable batteries needs to be avoided. The present invention is intended to free note-size computers from tangling cords and time-consuming rechargers. [0151] The advantages of high speed and high resolution attributed to ferroelectric liquid crystal materials have been known. [0152] The present invention in particular focuses more attention on the energy saving effects of the ferroelectric liquid crystal which have been less regarded. [0153] No such approach has been previously made. The energy saving effects will surely contribute to low power requirements of portable data processing apparatuses such as note-size computers. [0154] Although the embodiments of the present invention employ a display device of ferroelectric liquid crystal for utilization of memory effects, other memory devices of smectic liquid crystal or electrochromic material will be used with equal success. The liquid crystal display is not limited to a matrix drive as described and may be driven by a TFT drive system.

A data processing apparatus has a first processing unit for processing an input data, a second processing unit responsive to the data processed by the first processing unit for executing a processing dependent on the data and producing a display data, and a display unit having a display drive unit and a display device for displaying the display data. The second processing unit is selectively inactivated and activated under control of the first processing unit to reduce power consumption in the second processing unit. The display drive unit is also selectively inactivated and activated under control of the first processing unit to reduce power consumption in the display unit. The display device has a memory function that maintains its display image even when supply of a display drive signal from the display drive unit is stopped, so that a latest image before inactivation of the second processing unit and/or the display drive unit for power consumption reduction is visible by an operator during the inactivated and low power consumption state of the apparatus.

CROSS-REFERENCE TO RELATED APPLICATION [0001] This application is a continuation of copending International Application No. PCT/DE99/02766, filed Sep. 1, 1999, which designated the United States. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The invention relates to a frequency detection method for adjusting the clock signal frequency of a local oscillator to the data rate of a received binary data signal. The invention also relates to a frequency detector circuit for carrying out the method. [0004] For synchronizing clock signals, a PLL (phase locked loop) is frequently used in which the clock signal phase of a local oscillator is compared by a phase detector with the phase position of the received data signal and is adjusted. Because a phase locked loop does not lock if the frequency of the local oscillator differs too greatly from the data rate, a frequency comparison, by means of which the oscillator frequency is pretuned, must also be carried out. [0005] A method which is known in this context, and which is described in the paper by A. Pottbäcker et al: “A Si Bipolar Phase And Frequency Detector IC For Clock Extraction Up To 8 Gb/s” in “IEEE J. Sol.-State circuits”, Vol. 27, No. 12, December 1992, pp 1747-1751 and in the paper by D. G. Messerschmitt: “Frequency Detectors For PLL Acquisition In Timing And Carrier Recovery” in “IEEE Trans. Comm. Vol. COM-27, No. 9, September 1979, pp 1288-1295, is to use sequential circuits, for example of the rotation frequency detector, which samples a normal and a quadrature signal clock, i.e. a signal clock delayed by 90°, with the data signal in order to acquire the frequency information. [0006] Because received data signals are usually subject to more or less severe jitter, this method is in practice suitable only to a certain degree. When the jitter is severe, the frequency detector supplies incorrect information and can disrupt the clock signal synchronization even after the locking process has already occurred. [0007] In order to avoid this problem, in other approaches, a reference signal with quartz precision is used, with which signal the local oscillator is tuned into the locking-in range of the phase locked loop. The disadvantage of this method, which is known, for example, from the paper by Sam Yinshang Sun: “A High Speed High Jitter Tolerant Clock And Data Recovery Circuit Using Crystal Based Dual PLL” in “IEEE 1991 Bipolar Circuits And Technology Meeting”, pp 293-296, is that a reference signal has to be supplied or generated with a quartz. BRIEF DESCRIPTION OF THE DRAWINGS [0008] It is accordingly an object of the invention to provide an frequency detector circuit and a frequency detection method for adjusting the clock signal of a local oscillator to the data rate of a received binary signal which overcomes the above-mentioned disadvantageous of the prior art circuits and methods of this general type. In particular, it is an object of the invention to provide a method and a circuit to reliably compare the data rate of a received data signal and the clock signal frequency of a local oscillator without disruption even when there is severe jitter on the received data signal, and without having to generate a reference signal which has quartz precision with a quartz. [0009] With the foregoing and other objects in view there is provided, in accordance with the invention a frequency detection method for adjusting a clock signal frequency of a local oscillator to a data rate of a received binary data signal with a signal edge change probability of ½. The method includes steps of: obtaining a clock signal having a frequency from a local oscillator; frequency dividing the clock signal by a first division factor of 4 to obtain a first frequency divided clock signal; frequency dividing the first frequency divided clock signal by a second division factor to obtain a second frequency divided clock signal, and frequency dividing a received data signal by the second division factor to obtain a frequency divided data signal (the received data signal and the frequency divided clock signal are divided by the same division factor); determining a frequency of the second frequency divided clock signal and determining a frequency of the frequency divided data signal by running counting processes simultaneously in parallel in counters which provide two counter signals; in a subtractor, comparing the frequency of the second frequency divided clock signal with the frequency of the frequency divided data signal by obtaining a difference between the two counter signals; converting the difference obtained by the subtractor into an analog output signal; and using the analog output signal to control the frequency of the clock signal of the local oscillator. [0010] In transmission systems, the user information is usually scrambled because this is a way of improving the spectral properties of the data signal for the transmission. The probability that the state of a data signal bit will change at a possible time is ½ in this case. This property is used in the method according to the invention and exploited in order to obtain frequency information. [0011] A reset signal, which resets the counters operating in parallel and avoids an overflow at the subtractor, is advantageously derived from the final reading of the subtractor. [0012] In accordance with an added feature of the invention, after frequency adjustment of the clock signal of the local oscillator has taken place, the clock signal phase of the local oscillator is compared with the phase position of the received data signal by means of a PLL (phase locked loop) provided with a phase detector and a loop low-pass filter and adjusted. The analog output signal is fed to the loop low-pass filter in the PLL via an adder during the frequency adjustment, as a result of which the clock signal frequency of the local oscillator is modified until it has adjusted to the data rate of the received data signal. [0013] When the PLL locks, a lock signal, which is fed as a reset signal to the counters operating in parallel is then advantageously derived, with the result that the frequency controlling process is terminated. The PLL then starts its phase control operation. [0014] In accordance with an additional feature of the invention, after a specified number of clock signal pulses, a reset pulse which resets the counters operating in parallel, with the result that the frequency control process is switched off, is output by a counter designated as a plesiochronous counter. [0015] With the foregoing and other objects in view there is also provided, in accordance with the invention, a frequency detector circuit that includes a clock signal path for dividing a frequency of a clock signal applied to the clock signal path from a local oscillator. The clock signal path includes, in series, a 1:4 frequency divider, then a precounter, and finally a ring counter having an output providing a counting value. A data signal path is provided for dividing a frequency of a received binary data signal. The data signal path includes, in series, a precounter that is identical to the precounter in the clock signal path, and a ring counter having an output providing a counting value. The ring counter in the data signal path is identical to the ring counter in the clock signal path. A subtractor has a first input connected to the output of the ring counter in the clock signal path and a second input connected to the output of the ring counter in the data signal path. The subtractor outputs a difference between the counting value output by the ring counter in the clock signal path and the counting value output by the ring counter in the data signal path. A digital to analog converter receives the difference from the subtractor and converts the difference into an analog output signal for controlling the frequency of the clock signal of the local oscillator. [0016] Here, a 1:2-frequency divider is expediently connected in each case between the precounter and the ring counter both in the clock signal path and in the data signal path. [0017] The subtractor is advantageously designed in such a way that it also forms the difference between the counting values at its two inputs beyond the overflow limits of the ring counter. In addition, the subtractor also has a further output at which a reset signal is present if the subtractor reaches a specified positive or negative final reading. [0018] The reset signal is transmitted to the two ring counters and to the two 1:2-frequency dividers, in each case to their reset input. The reset signal can additionally be transmitted to the two precounters, in each case to their reset input. The aforesaid reset signals and possibly also a lock signal which is output by a phase locked loop when locking occurs after a frequency adjustment of the clock signal frequency of the local oscillator has been terminated, are also additionally conducted via an OR gate before being fed to the reset inputs for counters and dividers. [0019] Other features which are considered as characteristic for the invention are set forth in the appended claims. [0020] Although the invention is illustrated and described herein as embodied in a frequency detection method for adjusting a clock signal frequency and frequency detector circuit for carrying out the method, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. [0021] The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS [0022] The sole drawing FIGURE shows a frequency detector circuit for carrying out the inventive method. DESCRIPTION OF THE PREFERRED EMBODIMENTS [0023] Referring now to the sole drawing FIGURE, there is shown a local oscillator providing a clock signal that is inserted into a clock signal path 1 . The clock signal of the local oscillator is first divided in a 1:4 frequency divider 2 by the division factor “4”, with the result that the frequency which occurs then corresponds to the center of frequency of a received, binary data signal with edge change density ½. The received, binary data signal is fed into a data signal path 3 . A precounter 4 and 5 , respectively, is provided in each case in the data signal path 3 and in the clock signal path 1 . The two precounters 4 and 5 are provided to average out relatively long identical or 0-1 frequencies with brief signal edge change density 0 or 1. [0024] The output signals of the precounters 4 and 5 are divided once more by 2 in a 1:2 frequency divider 6 or 7 and increment, in each case, a downstream ring counter 8 or 9 , which count, for example, with 4 bits from 0 to 15 and then start at 0 again. A subtractor 10 has two inputs A and B, at which the output counting signals of the two ring counters 8 and 9 of the clock signal path 1 and of the data signal path 3 are fed. The subtractor 10 operates as stated in the book by U. Tietze; Ch. Schenk: “Halbleiter-Schaltungstechnik [Semiconductor circuit technology]”, seventh, revised edition, Springer Verlag [publishing house], Berlin, 1985, page 247. [0025] The subtractor 10 forms at its output D the difference between the ring counter readings fed to the inputs A and B, even beyond the overflow limits. For example with a 4-bit subtractor 10 , both 4 - 1 and 2 - 15 yield the difference 3. A digital/analog converter 11 connected to the output D of the subtractor 10 converts the counter difference into an analog voltage, the most significant bit being used as a sign bit for the two's complement. An example of this is given below: 0000=0 mV, 0001=10 mV, 0110=60 mV, 1111=−10 mV, 1100=−30 mV. The further output E of the subtractor 10 outputs a reset signal if the counter reading 2 n-1 −1 (for example 0111=7) or −2 n-1 (for example 1000=−8) is reached. [0026] The reset signal is logically connected via an OR gate 12 to the reset signal of a plesiochronous counter 13 . The plesiochronous counter 13 is so named because it resets the frequency detector into the initial state with an almost synchronous data and clock signal, and with a possibly usable lock signal of a PLL, and transmits it to the two 1:2 dividers 6 and 7 and the two ring counters 8 and 9 . The reset inputs are each designated in the FIGURE by R. [0027] In a variant which is not separately shown in the FIGURE, the reset signal can additionally be transmitted to the precounters 4 and 5 . By means of an adder 14 , the analog output voltage is transmitted to the loop low-pass filter 15 of the PLL which has a phase detector 16 for phase tracking and phase synchronizing the clock signal of the local oscillator. [0028] For the functional description which now follows of the frequency adjustment circuit illustrated schematically in the FIGURE, it is first assumed that the data signal rate is higher than the clock signal frequency. In this case, the precounter 4 which is located in the data signal path 3 will supply pulses with a higher frequency than the precounter 5 configured in the clock signal path 1 . For this reason, the ring counter 8 will count more quickly via the 1:2 divider 6 than the ring counter 9 , with the result that a value which rises as a function of the difference frequency is output at the output D by the subtractor 10 . [0029] The digital/analog converter 11 generates a positive analog voltage from the value output by the subtractor 10 . The positive analog voltage is transmitted via the adder 14 to the loop low-pass filter 15 . As a result, the clock frequency of the local oscillator is increased until it has adjusted to the data signal rate. The signal of the phase detector 16 in the PLL does not play any role here because it supplies the average value 0 when the PLL is not locked. [0030] If the subtractor 10 reaches the positive or negative final reading, for example +7, or in the event of an excessively high oscillator frequency −8, a reset pulse is generated at its output E and the reset pulse resets the ring counters 8 and 9 and the 1:2 dividers 6 and 7 via their reset inputs R. As a result, a new counting process is started and a difference with an incorrect sign is prevented from being formed. [0031] If the PLL locks because of the frequency adjustment by means of the signal of the phase detector 16 , and if, as a result, a lock signal is generated, this can be used to terminate the frequency control process. In this case it is possible to dispense with the so-called plesiochronous counter 13 . A possible circuit for a lock indicator is a window comparator which outputs a signal if the voltage of the phase detector 16 does not exceed certain limits for a sufficiently long time. [0032] If there is no lock signal available, the plesiochronous counter 13 assumes the function of preventing possible disruptive actions of the frequency detector if the PLL is already locked. The output signal of the precounter 4 is more or less irregular as a result of statistically distributed bit change frequencies or identical sequences. Without regular resetting of the ring counters 8 and 9 , their counter readings would gradually “run away from one another” and generate faulty frequency detector signals. [0033] For this reason, after a certain number of clock pulses, a reset pulse which resets the ring counters 8 and 9 is output by the plesiochronous counter 13 . The greater the plesiochronous counter 13 , the more precise the control of the frequency; and at the same time the sensitivity to deviations of the data signal from the edge change density ½ rises. [0034] Because the divided data signal is, by its very nature, not regular, the output pulses of the precounters 4 and 5 can occur with a random shift with respect to one another. In order to prevent this from causing the frequency detector to generate an output signal, the 1:2-frequency dividers 6 and 7 are inserted and they are reset by the plesiochronous counter 13 , by the lock signal, or by the signal of the output E of the subtractor 10 . [0035] A few essential dimensioning rules for the frequency control circuit illustrated in the FIGURE will now be given: [0036] For the precounters 4 and 5 , the following applies: in order to make the circuit tolerant to g successive identical bits, the precounter must count to g/4. [0037] For the plesiochronous counter 13 , the following applies: a reset pulse will be generated by this counter 13 before the ring counters 8 and 9 have a difference of 1 if the frequency difference Δf is present at the input. The beat frequency between the ring counter inputs is Δf/8VZ, where VZ is the precounter step of the precounters 4 and 5 . PZ which is subsequently given is the steps of the plesiochronous counter 13 . [0038] In order to obtain this frequency at the output of the plesiochronous counter 13 , the following must apply: (Δf/8VZ)*(4VZ)*(PZ)=f clock or PZ=2 f clock /Δf. If, for example, the locking-in range of the PLL is dimensioned at 10 MHz, and if the clock frequency is f clock =1 GHz, the plesiochronous counter 13 must count up to 200. [0039] For the ring counters 8 and 9 the following applies: with large ring counters 8 and 9 , a linearly operating frequency control loop can be set up; the manipulated value becomes proportional to the difference frequency. As a result, an optimum frequency locking-in behavior can be obtained. If low requirements are made of the frequency locking-in behavior, a simple 3-bit or 4-bit counter is sufficient. A 2-bit counter is not possible because of the resetting output E. [0040] For the frequency control loop the following applies: in order to make the frequency control stable, the annular amplification must not be too large. The output signal of the digital/analog converter 11 must therefore not be too large. An analytic stability calculation is dispensed with at this point. [0041] The described frequency adjustment circuit according to the invention is used in particular in receiver circuits at the end of transmission links of a telecommunications and data transmission network.

In a frequency detection method for adjusting a clock signal frequency to the data rate of a received data signal, the clock signal which is predivided by a factor of 4. The predivided clock signal and the received data signal are each frequency-divided by the same division factor. The frequencies of the two frequency-divided signals are then determined counting processes and are compared by a subtractor. The frequency difference that is determined is then converted into an analog output signal for controlling the clock signal frequency. This method can be applied in the transmission of data.

CLAIM OF PRIORITY [0001] The present application claims priority from Japanese patent application JP 2007-249835 filed on Sep. 26, 2007, the content of which is hereby incorporated by reference into this application. BACKGROUND [0002] This invention relates to access control, and more particularly to data management and access control based on a storage permitted location and an access permitted location of data in a group of computer systems intercoupled via a network. [0003] With higher performance and lower prices of computer systems, the use of the computer systems have recently been diffused in various industries and applications. Accordingly, data conventionally handled on paper media or the like have been computerized, and electronically stored by the computer system. [0004] Additionally, a form where a plurality of computer systems are intercoupled via a network has rapidly progressed. Distributed management and distributed processing of data can be realized, and so availability, reliability, and performance which had been difficult to be realized only by one computer system has become possible. [0005] In the form of intercoupling the plurality of computer systems via the network, it has become more important to provide a technology of efficiently managing data and a technology of controlling access for the purpose of improving convenience for computer system users. [0006] An overlay network technology of building and providing a logical network structure by hiding a physical network structure for intercoupling a plurality of computer systems has recently been used. The overlay network technology enables transparent access to the computer system irrespective of an installation location of the computer system to be used. [0007] By using the overlay network technology, for example, file share services of a peer-to-peer form for distributing and storing shared files can be realized on the computer systems which build the overlay network. [0008] In the file share services, the users can know on which of the computer systems shared files are present by requesting file acquisition based on identification information of the shared files to be obtained. Once the presence location of the shared file is known, each user can obtain the shared file by accessing a relevant arbitrary computer system. [0009] In the case of accessing the arbitrary computer system, the user doesn't have to know where the computer system to be accessed is actually present but has to know only identification information of the computer system to be accessed in the overlay network. Based on the identification information, the user can access the computer system where the shared file is present via the overlay network. [0010] Conventionally, to build the overlay network, identification information of a participating computer system, and identification information in the network which becomes necessary for accessing via an actual network are necessary. For example, the former is a host name of the computer system, and the latter is an IP address allocated to the computer system. [0011] The computer system participating in the overlay network has to manage such identification information, and exchange identification information with the other computer system participating in the overlay network to update contents. [0012] By executing the updating properly, the computer system can dynamically participate in or withdraw from the overlay network as occasion demands, and the computer systems which participate in the overlay network can be easily managed. [0013] For management of the computer systems which participate in the overlay network, two methods are available, i.e., a method of managing information of all participating computer systems in each computer system, and a method of managing only information of some computer systems in each computer system. As each computer system can understand all the computer systems participating in the overlay network, the former method has a feature that a node storing a shared file is searched for in the case of actually accessing the shared file, and efficiency is high when access is made to the shared file. On the other hand, as update information has to be reflected in all the participating computer systems each time the computer system participates in or withdraws from the overlay network, there is a problem of reduced efficiency for managing the participating computer systems. [0014] In the case of the latter method, each computer system manages information of some computer systems among the computer systems participating in the overlay network. Accordingly, updating of information managed by each computer system each time a computer system participates in or withdraws from the overlay network can be minimized, and its influence can be reduced. In the case of the latter method, when access to the shared file is actually made, by making an inquiry to the other computer systems participating in the overlay network, information of the computer system which has participated in or withdrawn from the network can be obtained. In this case, overheads occur because of the inquiry made about the information of the computer system. However, the overheads are much smaller as compared with those when the management information of the computer systems participating in the overlay network is updated. Especially, overheads are conspicuously large when a large-scale overlay network is run. SUMMARY [0015] Regarding the latter method, JP 2007-28400 A discloses a technology of reducing actual network loads by building an overlay network based on localities of participating computer systems. According to the technology described in JP 2007-28400 A, when a computer system that is to participate in the overlay network transmits request information of participation in the overlay network, information indicating a reachable range of the transmitted request information is set. Thus, propagation of the request information of participation can be locally limited, and updating of management information of each computer system can be locally suppressed when the computer system participates in the overlay network. [0016] In the case of the technology described in JP 2007-28400 A, however, when file share services using the overlay network are provided, the location of a computer system which stores a shared file cannot be designated or controlled. For example, if a shared file whose distributable or sharable countries or regions are limited because of a copyright or other problems is shared among the file share services described in JP 2007-28400 A, the shared file may be stored in a computer system installed in a country or a region where distribution and sharing are not permitted. Management of the file which cannot be used in the computer system reduces storage use efficiency of the computer system. Additionally, because the location (country or region) where an access requester of access to the shared file is present is not identified at the time of access control, there arises a problem in that control carried out to deny access for a user present in a location where access not permitted is difficult. For example, because where the access requester is present is not identified, access to contents denied for access from the US cannot be denied to users permitted for access in Japan during their stay in the US. [0017] In the case of the technology described in JP 2007-28400 A, communication charges between the computer systems in the overlay network or between Internet service providers (ISP) for providing network connection services are not taken into consideration. Thus, even when network loads can be reduced, extra communication fees may be charged. The increase of communication charges may increase ISP loads, consequently reducing quality of ISP network services. [0018] A problem of the former case is that control of the shared file storage location and access control to the shared file are carried out without taking localities in the overlay network into consideration. It is expected that information shared and distributed via the network will increase, and information involving rights regarding copyrights will be contained. Accordingly, for providing file share services using the overlay network, a technology solving this problem will be necessary. [0019] A problem of the latter case is that the network is used without taking actual communication charges of the network into consideration. It is expected that a network represented by the Internet will come into wider use, thereby increasing an information distribution amount. In such a case, to enable the ISP providing network connection services to continuously provide proper network service quality, a technology capable of minimizing use of a network which increases ISP loads will be necessary. [0020] A representative aspect of this invention is as follows. That is, there is provided a controller installed in a computer system, the computer system having: a plurality of data storage systems for storing copies of data in a distributed manner; at least one controller for controlling access to the data stored in the plurality of data storage systems; and a network for coupling the at least one controller. The each controller comprising: an interface coupled to the network; a processor coupled to the interface; and a storage unit coupled to the processor. The storage unit holds attribute information indicating whether to permit access to the data. The processor is configured to: receive a writing request of the data from a client computer coupled to the network; judge whether the each controller permits the requested writing based on the held attribute information and information of a location where the each controller is installed; and write the data in a data storage system controlled by a controller judged to permit the writing. [0021] According to the aspect of this invention, by designating the installation location of the storage destination controller of shared data and the access permitted location for each piece of the data, access from the location where the access is not permitted can be denied. Moreover, by suppressing storage of the data in the controller installed in the location where the storage of the shared data is not permitted, unnecessary communication can be removed to suppress wasteful use of the storage system. [0022] At the time of accessing the data, by carrying out control to preferentially access the data of the controller with a minimum communication charge, communication charges necessary for file share services can be reduced. The reduction of communication charges enables reduction of loads of the ISP for providing network connection services, and the ISP can provide sustainable network services of proper quality. BRIEF DESCRIPTION OF THE DRAWINGS [0023] The present invention can be appreciated by the description which follows in conjunction with the following figures, wherein: [0024] FIG. 1 is a configuration diagram showing a configuration of a computer system in accordance with a first embodiment of this invention. [0025] FIG. 2 is a block diagram showing a hardware configuration of the storage node in accordance with the first embodiment of this invention; [0026] FIG. 3 is a block diagram showing a hardware configuration of the client node in accordance with the first embodiment of this invention; [0027] FIG. 4 is a diagram showing a configuration of the node management table in accordance with the first embodiment of this invention; [0028] FIG. 5 is a diagram showing a configuration of the node installation location information management table in accordance with the first embodiment of this invention; [0029] FIG. 6 is a diagram showing a configuration of the shared file metadata management table in accordance with the first embodiment of this invention; [0030] FIG. 7 is a diagram showing schematically a shared file which is stored in the storage nodes in accordance with the first embodiment of this invention; [0031] FIG. 8 is a flowchart showing a node registration process in accordance with the first embodiment of this invention; [0032] FIG. 9 is a flowchart showing a node search process in accordance with the first embodiment of this invention; [0033] FIG. 10 is a flowchart showing a file registration process in accordance with the first embodiment of this invention; [0034] FIG. 11 is a flowchart showing a file migration/replication process in accordance with the first embodiment of this invention; [0035] FIG. 12 is a flowchart showing a file access process in accordance with the first embodiment of this invention; [0036] FIG. 13 is a configuration diagram showing a configuration of a computer system in accordance with a second embodiment of this invention. [0037] FIG. 14 is a block diagram showing a hardware configuration of the management server in accordance with the second embodiment of this invention; [0038] FIG. 15 is a diagram showing a configuration of the ISP information management table in accordance with the second embodiment of this invention; [0039] FIG. 16 is a diagram showing a configuration of the node management table in accordance with the second embodiment of this invention; [0040] FIG. 17 is a diagram showing a configuration of the node installation location information management table in accordance with the second embodiment of this invention; [0041] FIG. 18 is a flowchart showing a node search process in accordance with the second embodiment of this invention; and [0042] FIG. 19 is a flowchart showing a file access process in accordance with the second embodiment of this invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0043] Referring to the drawings, the preferred embodiments of this invention will be described bellow. First Embodiment [0044] First, a system according to a first embodiment of this invention will be described. [0045] FIG. 1 illustrates a configuration of the computer system according to the first embodiment of this invention. [0046] The computer system includes ISPs 1 to 5 . The ISPs 1 to 5 are intercoupled via Internet 10 . An authentication server 3000 is coupled to the Internet 10 . [0047] A storage node A 1100 and client nodes 2000 and 2100 are coupled to the ISP 1 . A storage node B 1200 and client nodes 2200 and 2300 are coupled to the ISP 2 . A storage node C 1300 and client nodes 2400 and 2500 are coupled to the ISP 3 . A storage node D 1400 and client nodes 2600 and 2700 are coupled to the ISP 4 . A storage node E 1500 and client nodes 2800 and 2900 are coupled to the ISP 5 . [0048] The storage node A 1100 cooperates with the other storage node (e.g., storage node B 1200 ) via the Internet 10 to build an overlay network, thereby providing file share services. The storage nodes B 1200 , C 1300 , D 1400 , and E 1500 have similar configuration to the storage node A. [0049] The client node 2000 is a device of a user who utilizes file share services. The client nodes 2100 , 2200 , 2300 , 2400 , 2500 , 2600 , 2700 , 2800 , and 2900 have similar configuration to the client node 2000 . [0050] The ISPs 2 to 5 have similar configuration to the ISP 1 . The ISPs 1 to 3 are included in Area 11 . The ISPs 4 and 5 are included in Area 12 . The Areas 11 and 12 indicate the same location (e.g., country or region). [0051] The authentication server 3000 authenticates a presence location of a client (e.g., client node 2000 ) which requests access. [0052] FIG. 1 shows five ISPs. However, any number of ISPs may be set. A network structure to which each ISP is coupled is not limited to the form shown in FIG. 1 . An arbitrary network structure (e.g., ring type or star type) may be employed. [0053] In an example shown in FIG. 1 , one storage node is coupled to each ISP. However, any number of storage nodes may be coupled. Two client nodes are coupled to each ISP. However, any number of client nodes may be coupled. [0054] FIG. 2 illustrates a hardware configuration of the storage node A 1100 according to the first embodiment of this invention. [0055] The storage node A 1100 includes a processor 1110 , a memory 1120 , an external storage system I/F 1140 , and a network IF 1150 . These components are intercoupled via a bus 1160 . The storage node A 1100 is coupled to an external storage system 1170 via the external storage system I/F 1140 . [0056] The processor 1110 executes a program stored in the memory 1120 to control the entire storage node A 1100 . [0057] The memory 1120 temporarily stores the program and/or data executed by the processor 1110 . The memory 1120 may include a semiconductor memory such as a RAM. [0058] The memory 1120 stores an external storage system I/F control program 1121 , a network I/F control program 1122 , a local file system control program 1123 , a distributed file system control program 125 , a node management table 4000 , a node installation location information management table 4100 , a shared file metadata management table 4200 , and a cache memory 1130 . [0059] The external storage system I/F control program 1121 controls the external storage system I/F 1140 . The network I/F control program 1122 controls the network I/F 1150 . [0060] The local file system control program 1123 contains a cache memory control subprogram 1124 . The local file system control program 1123 controls a file system provided by the storage node A 1100 . The cache memory control subprogram 1124 controls the cache memory 1130 . [0061] The distributed file system control program 1125 contains a query request control subprogram 1126 , a query response control subprogram 1127 , a basic control subprogram 1131 , a file registration subprogram 1132 , a file replication/migration subprogram 1133 , and a file access subprogram 1134 . [0062] The distributed file system control program 1125 controls file share services which have used the overlay network. [0063] The query request control subprogram 1126 controls a query request transmitted to the other storage node constituting the overlay network. The query request is a request transmitted when information (e.g., identification information of the other storage node constituting the overlay network) is desired to be obtained from the other storage node. [0064] The query response control subprogram 1127 receives a query request from the other storage node constituting the overlay network, executes a process of obtaining requested information, and controls a response of a processed result. [0065] The basic control subprogram 1131 manages information of the storage node A 1100 . For example, the basic control subprogram 1131 registers information (identification information) regarding the storage node A 1100 in the node management table 4000 . [0066] The file registration subprogram 1132 registers a shared file in the overlay network. [0067] The file replication/migration subprogram 1133 replicates or migrates the shared file registered in the overlay network. [0068] The file access subprogram 134 controls access requested to the shared file registered in the overlay network from a client (e.g., client node 2100 ). [0069] The node management table 4000 holds identification information of a storage node present in the overlay network. The node management table 4000 will be described below referring to FIG. 4 . [0070] The node installation location information management table 4100 holds information regarding a location where a storage node is present. The node installation location information management table 4100 will be described below referring to FIG. 5 . [0071] The shared file metadata management table 4200 holds metadata registered in the shared file stored in the storage node. The shared file metadata management table 4200 will be described below referring to FIG. 6 . [0072] The cache memory 1130 is used for shortening access response time when the local file system control program 2023 accesses a file managed by the file system. [0073] The external storage system I/F 1140 is an interface for accessing the external storage system 1170 . The network I/F 1150 is an interface for accessing the other system coupled via the network. [0074] The external storage system 1170 stores a shared file. The external storage system 1170 may include, for example, a hard disk drive (HDD). Alternatively, a semiconductor memory device such as a flash memory may be used. [0075] FIG. 3 illustrates a hardware configuration of the client node 2000 according to the first embodiment of this invention. [0076] The client node 2000 includes a processor 2010 , a memory 2020 , an external storage system I/F 2040 , and a network IF 2050 . These components are intercoupled via a bus 2060 . The client node 2000 is coupled to an external storage system 2070 via the external storage system I/F 2040 . [0077] The processor 2010 executes a program stored in the memory 2020 to control the entire client node 2000 . [0078] The memory 2020 temporarily stores the program and/or data executed by the processor 2010 . The memory 2020 may include a semiconductor memory such as a RAM. [0079] The memory 2020 stores an external storage system I/F control program 2021 , a network I/F control program 2022 , a local file system control program 2023 , a distributed file system client control program 2025 , the node management table 4000 , and a cache memory 2030 . [0080] The external storage system I/F control program 2021 controls the external storage system I/F 2040 . The network I/F control program 2022 controls the network I/F 2050 . [0081] The local file system control program 2023 contains a cache memory control subprogram 2024 . The local file system control program 2023 controls a file system provided by the client node 2000 . The cache memory control subprogram 2024 controls the cache memory 2030 . [0082] The distributed file system client control program 2025 contains a query request control subprogram 2026 , and a basic control subprogram 2031 . [0083] The distributed file system client control program 2025 controls file share services which have used the overlay network. [0084] The query request control subprogram 2026 transmits a query request, a file registration request, a shared file access request, and the like to the storage node for providing file share services using the overlay network. [0085] The basic control subprogram 2031 manages information of the client node 2000 . For example, the basic control subprogram 2031 registers information (identification information) regarding a storage node accessed by the client node 2000 in the node management table 4000 . [0086] The node management table 4000 holds only information regarding the storage node directly accessed first from the client node 2000 . The node management table 4000 of the client node 2000 and the node management table 4000 of the storage node A 1100 may be synchronized to hold the same information. In the case of holding the same information, the same information as that of the node management table 4000 held by the storage node A 1100 may be held in the node management table 4000 of the client node 2000 . [0087] The cache memory 2030 is used for shortening access response time when the local file system control program 2023 accesses a file managed by the file system. [0088] The external storage system I/F 2040 is an interface for accessing the external storage system 2070 . The network I/F 2050 is an interface for accessing the other system coupled via the network. [0089] The external storage system 2070 stores a program or user data. The external storage system 2070 may include, for example, a hard disk drive (HDD). Alternatively, a semiconductor memory device such as a flash memory may be employed. [0090] FIG. 4 illustrates a configuration of the node management table 4000 according to the first embodiment of this invention. [0091] The node management table 4000 holds identification information of a storage node recognized to be present in the overlay network. [0092] The node management table 4000 includes a node name 4010 and identification information 4020 . [0093] The node name 4010 is information for identifying a storage node in the overlay network. In the node name 4010 shown in FIG. 4 , information of a character string is stored. However, information of a numerical value such as node ID may be stored. [0094] The identification information 4020 is identification information of a storage node recognized in a normal network. The identification information 4020 is used for designating an access destination when the storage node is accessed via the network. In the identification information 4020 shown in FIG. 4 , an IP address is stored. However, for example, ID information for specifying a storage node may be stored. Alternatively, information of a character string may be stored. [0095] In an example shown in FIG. 4 , five pieces of storage node information are stored. “STORAGE NODE A” and “ 10 . 20 . 30 . 40 ” are respectively stored in a node name 4010 and identification information 4020 of a first line of the node management table 4000 . These indicate that a storage node named “STORAGE A” participating in the overlay network is present, and “STORAGE NODE A” can be accessed based on information of the destination “ 10 . 20 . 30 . 40 ”. [0096] FIG. 5 illustrates a configuration of the node installation location information management table 4100 according to the first embodiment of this invention. [0097] The node installation location information management table 4100 manages information regarding a location where a storage node is present. [0098] The node installation location information management table 4100 includes node installation location information 4110 . The node installation location information 4110 is information for identifying a location where a storage node is installed. [0099] In the node installation location information 4100 shown in FIG. 5 , certain information or all pieces of information regarding an actual address are stored. However, for example, identification information (IP address) may be stored in a tiered manner. Alternatively, ID information for specifying a location may be stored. [0100] In an example shown in FIG. 5 , two pieces of information regarding an installation location of a storage node are stored. In the node installation location information 4110 of the node installation location information management table 4100 , “JAPAN” and “TOKYO” are stored. These indicate that the storage node A 1100 is installed in a location called “TOKYO” of “JAPAN”. [0101] FIG. 6 illustrates a configuration of the shared file metadata management table 4200 according to the first embodiment of this invention. [0102] The shared file metadata management table 4200 manages metadata registered in a shared file stored in the external storage system 1170 coupled to the storage node A 1100 for each shared file. [0103] The shared file data management table 4200 includes, in addition to existing metadata (e.g., storage date and keyword), information of storing permitted location 4210 , information of storing denied location 4220 , information of access permitted location 4230 , and information of access denied location. [0104] The information of storing permitted location 4210 is for specifying a location where a shared file can be stored. Specifically, a client (e.g., client node 2000 ) can store a shared file only in an external storage system coupled to a storage node installed in a location designated by the information of storing permitted location 4210 . [0105] In contrast to the information of storing permitted location 4210 , the information of storing denied location 4220 is information for designating a location where a shared file cannot be stored. Specifically, a client (e.g., client node 2000 ) cannot store any shared file in an external storage system coupled to a storage node installed in a location designated by the information of storing denied location 4220 . [0106] The information of access permitted location 4230 is information for designating a location where access is permitted when a request of access to a shared file is received. Specifically, only an access requester (e.g., client node 2000 ) judged to be present in a location designated by the information of access permitted location 4230 can access a shared file. The access to the shared file means reading of the shared file, writing of the shared file, copying of the shared file, or migration of the shared file. [0107] In contrast to the information of access permitted location 4230 , the information of access denied location 4240 is information for designating a location where access is denied when a request of access to a shared file is received. Specifically, an access requester judged to be present in a location designated by the information of access denied location 4240 cannot access a shared file. [0108] In an example shown in FIG. 6 , one piece of information is stored. However, a plurality of pieces of information may be stored as occasion demands. [0109] When information of the same location is stored in the information of storing permitted location 4210 and the information of storing denied location 4220 , contents stored in the information of storing denied location 4220 are preferentially used. When information of the same location is stored in the information of access permitted location 4230 and the information of access denied location 4240 , contents stored in the information of access denied location 4240 are preferentially stored. [0110] As shown in FIG. 6 , when no value is stored, “Null” is stored. When “Null” is stored, there is no location to be designated. [0111] In an example shown in FIG. 6 , the information of storing permitted location 4210 , the information of storing denied location 4220 , the information of access permitted location 4230 , and the information of access denied location 4240 are stored in the shared file metadata management table 4200 . [0112] “JAPAN”, “Null”, “Null”, and “UNITED STATES” are stored in the information of storing permitted location 4210 , the information of storing denied location 4220 , the information of access permitted location 4230 , and the information of access denied location 4240 of a first line of the shared file metadata management table 4200 . These indicate that a shared file can be stored in a storage node installed in a location “JAPAN”, and access from an access requester present in a location “UNITED STATES” is denied. [0113] FIG. 7 schematically illustrates which of the storage nodes a shared file is stored in the system configuration of the first embodiment of this invention. [0114] In an example shown in FIG. 7 , “A”, “B”, “C”, and “D” are stored as shared files in the external storage systems. In this case, the shared file “A” is distributed to be stored in two locations, i.e., the external storage system 1170 coupled to the storage node A 1100 and the external storage system 1370 coupled to the storage node C 1300 . The shared file “B” is distributed to be stored in the external storage system 1170 coupled to the storage node A 1100 , and the external storage system 1570 coupled to the storage node E 1500 . The shared file “C” is distributed to be stored in the external storage system 1270 coupled to the storage node B 1200 , the external storage system 1370 coupled to the storage node C 1300 , and the external storage system 1470 coupled to the storage node D 1400 . The shared file “D” is distributed to be stored in the external storage system 1470 coupled to the storage node D 1400 , and the external storage system 1570 coupled to the storage node E 1500 . [0115] It is presumed that for the shared file “A”, information “Area 11 ” is stored in the information of storing permitted location 4210 of the shared file metadata management table 4200 . In this case, when the shared file “A” is registered in file share services, a storage node which becomes a storage destination of a shared file is selected from the storage nodes A 1100 , B 1200 , and C 1300 included in the “Area 11 ”. [0116] FIG. 8 is a flowchart showing a node registration process according to the first embodiment of this invention, which is executed by the basic control subprogram 1131 and the query request control subprogram 1126 . [0117] The node registration process is executed by a participating storage node (here, referred to as storage node A 1100 ) when a new storage node participates in the overlay network. [0118] First, the basic control subprogram 1131 of the storage node A 1100 gets an area for storing information of the storage node A 1100 in the node management table 4000 , and initializes the got area (S 101 ). [0119] For the overlay network which is a target of participation, the basic control subprogram 1131 of the storage node A 1100 judges whether another storage node for registering node information (e.g., node name and identification information) of the storage node A 1100 is present (S 102 ). In other words, in the step S 102 , whether the storage node A 1100 is a first storage node to participate in the overlay network is judged. [0120] If another storage node for registering the node information is not present, the storage node A 1100 is a first storage node to participate in the overlay network. Accordingly, the node information of the storage node A 1100 does not have to be registered in the other storage node. In this case, the process proceeds to step S 108 . [0121] On the other hand, if another storage node for registering the node information is present, the other storage node has participated in the overlay network. Accordingly, the storage node A 1100 has to register own node information in the other storage node participating in the overlay network. In this case, the process proceeds to step S 103 . To judge whether the other storage node participates in the overlay network, it can be judged based on whether identification information (e.g., IP address) regarding the other storage node is held when participating in the overlay network. [0122] The query request control subprogram 1126 of the storage node A 1100 requests node registration in the overlay network together with information regarding the storage node A 1100 to the other storage node which participates in the overlay network (S 103 ). [0123] When participating in the overlay network, node information provided beforehand is designated to be transmitted to a storage node (hereinafter, referred to as target node) which requests node registration. The node information transmitted together with the node registration request contains a node name of the storage node A 1100 , and identification information (e.g., IP address) in the network. [0124] Upon reception of the node registration request, a node registration process is executed by the basic control subprogram 1131 and the query response control subprogram 1127 . [0125] First, the query response control subprogram 1127 of the target node receives the node registration request (S 104 ). [0126] The basic control subprogram 1131 of the target node stores information of the storage node A 1100 which has requested the node registration in the node management table 4000 of the target node (S 105 ). [0127] The query response control subprogram 1127 of the target node transmits the node information stored in the node management table 4000 to the storage node A 1100 (S 106 ). Specifically, the basic control subprogram 1131 of the target node reads the node information (e.g., node name 4010 and identification information 4020 ) stored in the node management table 4000 , and the query response control subprogram 1127 of the target node transmits the read node information together with a response of node registration success to the storage node A 1100 . [0128] The basic control subprogram 1131 of the storage node A 1100 stores the node information transmitted from the target node in the node management table 4000 of the storage node A 1100 (S 107 ). Specifically, the query request subprogram 1126 of the storage node A 1100 receives a response of the node registration from the target node. When the response is a node registration success, the basic control subprogram 1131 of the storage node A 1100 stores the node information transmitted together with the node registration response in the node management table 4000 of the storage node A 1100 . Then, the process is finished. [0129] In step S 108 , the basic control subprogram 1131 of the storage node A 1100 stores the node information of the storage node A 1100 in the node management table 4000 (S 108 ). Then, the process is finished. [0130] FIG. 9 is a flowchart showing a node search process according to the first embodiment of this invention, which is executed by the basic control subprogram 1131 and the query request control subprogram 1126 . [0131] The node search process is carried out when the storage node (here, referred to as storage node A 1100 ) participating in the overlay network searches for other participating storage nodes. [0132] First, the basic control subprogram 1131 of the storage node A 1100 selects a necessary number of arbitrary storage nodes from a list of storage nodes registered in the node management table 4000 (S 111 ). [0133] The necessary number of storage nodes is selected, because, when node search is requested to all the storage nodes registered in the node management table 4000 , node information of the entire overlay network may be obtained, but process loads of storage node searching and updating of the node management table 4000 may increase. Thus, in this case, the necessary number of nodes is selected, and node search is requested to the selected storage node. For a method of selecting storage nodes, for example, a method of randomly selecting storage nodes from the node management table 4000 is available. The necessary number can be changed flexibly by an administrator. [0134] The query request control subprogram 1126 of the storage node A 1100 transmits contents of the node management table 4000 held by the storage node A 1100 to the storage node (hereinafter, referred to as target node) selected in the step S 111 to request acquisition of node information (e.g., node name and identification information (S 112 ). [0135] The contents of the node management table 4000 to be transmitted contain all data (e.g., node name and identification information). Only certain data (e.g., only identification information) may be contained. [0136] Upon reception of the node information acquisition request, a node search process is executed by the basic control subprogram 1131 and the query response control subprogram 1127 . [0137] First, the query response control subprogram 1127 of the target node receives the node information acquisition request transmitted in the step S 112 (S 113 ). [0138] The basic control subprogram 1131 of the target node stores node information transmitted from the storage node A 1100 which has requested the acquisition of node information in the node management table 4000 of the target node (S 114 ). [0139] The query response control subprogram 1127 of the target node transmits the node information stored in the node management table 4000 to the storage node A 1100 (S 115 ). Specifically, the basic control subprogram 1131 of the target node read the node information stored in the node management table 4000 . The query response control subprogram 1127 of the target node transmits the read node information together with a response to the node information acquisition request to a request source (storage node A 1100 ) of the node information acquisition. [0140] As in the case of the step S 112 , the contents of the node information to be transmitted contain all data (e.g., node name 4010 and identification information 4020 ). Only certain data (e.g., only identification information 4020 ) may be contained. [0141] The basic control subprogram 1131 of the storage node A 1100 stores the node information transmitted from the target node in the step S 115 in the node management table 4000 of the storage node A 1100 (S 116 ). Specifically, the query request subprogram 1126 of the storage node A 1100 receives a response to the node information acquisition request from the target node. The basic control subprogram 1131 of the storage node A 1100 stores the node information transmitted together with the response in the node management table 4000 of the storage node A 1100 . Then, the process is finished. [0142] The node search process is carried out to, for example, periodically update information. When node registration is requested, the node search process may be executed to quickly propagate information of the storage node which has requested the node registration to the other storage node. [0143] The node search process may be executed each time a node is registered in the overlay network or a storage node withdraws from the network. [0144] Only an outline of a node withdrawal process will be described without using any drawings. For example, upon execution of the node search process, when the target node tries to access a withdrawn storage node, by using a storage node which has not responded within a predetermined time as a withdrawn node, information of a storage node not responded from the own node management table 4000 is deleted. [0145] FIG. 10 is a flowchart showing the file registration process carried out by the file registration subprogram 1132 according to the first embodiment of this invention. [0146] The file registration process is executed by a storage node (here, referred to as storage node A 1100 ) which requests registration of a shared file when a new shared file is registered in the overlay network. [0147] First, the file registration subprogram 1132 obtains the number of stored redundancies of a new shared file to be registered (hereinafter, referred to as target file) to store it in a temporary variable “S” (S 121 ). The number of stored redundancies is the number of copies of the target file to distribute and store the target file. For the number of stored redundancies, for example, a value designated as metadata of the target file is used. Alternatively, a value defined by the entire system may be used. [0148] The file registration subprogram 1132 obtains node list information from the node management table 4000 to store it in a temporary area (S 122 ). The node list information contains, for example, a node name and identification information. [0149] The file registration subprogram 1132 judges whether a process of step S 124 and the following steps has been finished for all the storage nodes registered in the node list information stored in the step S 122 (S 123 ). [0150] If the process of the step S 124 and the following steps has been finished for all the storage nodes, the necessary number of storage nodes (number of stored redundancies) which become storage destinations of the target file is not secured. Thus, the process proceeds to step S 133 . [0151] On the other hand, if the process of the step S 124 and the following steps has not been finished for all the storage nodes, the file registration subprogram 1132 has to get the necessary number of storage nodes which become storage destinations of the target file. In this case, the process proceeds to the step S 124 . [0152] The file registration subprogram 1132 selects storage destination node candidates from the node list information obtained in the step S 122 to create a storage destination node candidate list (S 124 ). For a method of selecting the storage destination node candidates, for example, a method of selecting storage node candidates in order registered in the node list information is available. Alternatively, a method of randomly selecting storage node candidates may be used. Otherwise, a method of selecting storage node candidates by using hash values of node names so that the storage nodes of the storage destination can be uniformly distributed may be used. [0153] The file registration subprogram 1132 judges whether a process of step S 127 and the following steps has been finished for all the storage nodes registered in the storage destination node candidate list created in the step S 124 (S 125 ). [0154] If the process of the step S 127 and the following steps has been finished for all the storage nodes, the process proceeds to step S 126 . [0155] On the other hand, if the process of the step S 127 and the following steps has been finished for all the storage nodes, the file registration subprogram 1132 has to get the necessary number of storage nodes which become storage destinations of the target file. In this case, the process proceeds to the step S 127 . [0156] The file registration subprogram 1132 selects one storage node not subjected to a process of step S 128 and the following steps from the storage destination node candidate list (S 127 ). For a method of selecting one storage node, a method of randomly selecting a storage node from the storage destination node candidate list is available. [0157] The file registration subprogram 1132 judges whether the information of storing denied location 4220 of the target file contains location information of the selected storage node (S 128 ). Specifically, the file registration subprogram 1132 refers to the information of storing denied location 4220 stored as metadata of the target file in the shared file metadata management table 4200 to judge whether a location indicated by the information of storing denied location 4220 contains node installation location information 4110 stored in the node installation location information management table 4100 of the storage node selected in the step S 127 . [0158] If the location information of the selected storage node is contained, the file registration subprogram 1132 judges that the target file cannot be stored in the selected storage node. In this case, the process returns to the step S 125 . [0159] On the other hand, if the location information of the selected storage node is not contained, the process proceeds to step S 129 . [0160] The file registration subprogram 1132 judges whether the information of storing permitted location 4210 of the target file contains the location information of the selected storage node (S 129 ). Specifically, the file registration subprogram 1132 refers to information of storing permitted location 4210 stored as metadata of the target file in the shared file metadata management table 4200 to judge whether a location indicated by the information of storing permitted location 4210 contains node installation location information 4110 stored in the node installation location information management table 4100 of the storage node selected in the step S 127 . [0161] If the location information of the selected storage node is not contained, the file registration subprogram 1132 judges that the target file cannot be stored in the selected storage node. In this case, the process returns to the step S 125 . [0162] On the other hand, if the location information of the selected storage node is contained, the process proceeds to step S 130 . [0163] The file registration subprogram 1132 decides the selected storage node to be a storage destination node to decrement the temporary variable “S” (S 130 ). [0164] The file registration subprogram 1132 judges whether the temporary variable “S” is “0” (S 131 ). [0165] If the temporary variable “S” is not “0”, it is judged that the necessary number of storage nodes for storing the target file has not been secured. In this case, the process returns to the step S 125 . [0166] On the other hand, if the temporary variable “S” is “0”, it is judged that the necessary number of storage nodes for storing the target file has been secured. In this case, the process proceeds to step S 132 . [0167] The file registration subprogram 1132 copies the target file by a number of times equal to the number of stored redundancies to store the target file in the storage destination node decided in the step S 130 (S 132 ). If the storage destination node is another storage node (target node), the query request control program 1126 requests the target node to store the target file. The query response control program 1127 of the storage node requested to store the target file receives the storage request of the target file to store the target file. Then, a result of the storage is transmitted to a request source of the target file storage request. [0168] In step S 126 , the file registration subprogram 1132 deletes node information of the storage node registered in the storage destination node candidate list from the node list information stored in the temporary area (S 126 ). Then, the process returns to the step S 123 . [0169] In step S 133 , the file registration subprogram 1132 becomes an error because the necessary number of storage destination nodes cannot be found. In this case, the process is finished (S 133 ). [0170] FIG. 11 is a flowchart showing a file replication/migration process executed by the file replication/migration subprogram 1133 according to the first embodiment of this invention. [0171] When the shared file (hereinafter, referred to as target file) registered in the overlay network is copied or migrated over the storage nodes, the file replication/migration process is executed by the storage node (here, referred to as storage node A 1100 ) which requests copying or migration. [0172] The file replication/migration process enables adjustment of response performance of file access by increasing/decreasing the number of copies of the shared file, and maintenance of access availability to the shared file by migrating the shared file stored in a storage node to be stopped to another storage node beforehand. [0173] First, the file replication/migration subprogram 1133 obtains node list information from the node management table 4000 to store it in a temporary area (S 141 ). The node list information contains, for example, a node name and identification information. [0174] The file replication/migration subprogram 1133 judges whether a process of step S 143 and the following steps has been finished for all the storage nodes registered in the node list information stored in the step S 141 (S 142 ). [0175] If the process of the step S 143 and the following steps has been finished for all the storage nodes, no storage node which becomes a storage destination is secured. Thus, the process proceeds to step S 150 . [0176] On the other hand, if the process of the step S 143 and the following steps has not been finished for all the storage nodes, the file replication/migration subprogram 1133 has to get a storage node which become a storage destination of the target file. In this case, the process proceeds to the step S 143 . [0177] The file replication/migration subprogram 1133 selects storage destination node candidates from the node list information obtained in the step S 141 to create a storage destination node candidate list (S 143 ). For a method of selecting the storage destination node candidates, for example, a method of selecting storage node candidates in order registered in the node list information is available. Alternatively, a method of randomly selecting storage node candidates may be used. Otherwise, a method of selecting storage node candidates by using hash values of node names so that the storage nodes of the storage destination can be uniformly distributed may be used. [0178] The file replication/migration subprogram 1133 judges whether a process of step S 146 and the following steps has been finished for all the storage nodes registered in the storage destination node candidate list created in the step S 143 (S 144 ). [0179] If the process of the step S 146 and the following steps has been finished for all the storage nodes, the process proceeds to step S 145 . [0180] On the other hand, if the process of the step S 146 and the following steps has been finished for all the storage nodes, the file replication/migration subprogram 1133 has to get storage nodes which become storage destinations of the target file. In this case, the process proceeds to the step S 146 . [0181] The file replication/migration subprogram 1133 selects one storage node not subjected to a process of step S 147 and the following steps from the storage destination node candidate list (S 146 ). For a method of selecting one storage node, a method of randomly selecting a storage node from the storage destination node candidate list is available. [0182] The file replication/migration subprogram 1133 judges whether the information of storing denied location 4220 of the target file contains location information of the selected storage node (S 147 ). Specifically, the file replication/migration subprogram 1133 refers to the information of storing denied location 4220 stored as metadata of the target file in the shared file metadata management table 4200 to judge whether a location indicated by the information of storing denied location 4220 contains node installation location information 4110 stored in the node installation location information management table 4100 of the storage node selected in the step S 146 . [0183] If the location information of the selected storage node is contained, the file replication/migration subprogram 1133 judges that the target file cannot be copied or migrated to the selected storage node. In this case, the process returns to the step S 144 . [0184] On the other hand, if the location information of the selected storage node is not contained, the process proceeds to step S 148 . [0185] The file replication/migration subprogram 1133 judges whether the information of storing permitted location 4210 of the target file contains the location information of the selected storage node (S 148 ). Specifically, the file replication/migration subprogram 1133 refers to information of storing permitted location 4210 stored as metadata of the target file in the shared file metadata management table 4200 to judge whether a location indicated by the information of storing permitted location 4210 contains node installation location information 4110 stored in the node installation location information management table 4100 of the storage node selected in the step S 146 . [0186] If the location information of the selected storage node is not contained, the file replication/migration subprogram 1133 judges that the target file cannot be copied or migrated to the selected storage node. In this case, the process returns to the step S 144 . [0187] On the other hand, if the location information of the selected storage node is contained, the process proceeds to step S 149 . [0188] The file replication/migration subprogram 1133 copies or migrates the target file to the storage node (storage destination node) judged to contain the location information in the step S 148 (S 149 ). If the storage destination node is another storage node (target node), the query request control program 1126 requests the target node to copy or migrate the target file. The query response control program 1127 of the storage node requested to copy or migrate the target file receives the replication or migration request of the target file to store the replicated or migrated target file. Then, the target node transmits a result of the replication or the migration to the storage node A 1100 which has requested the replication or the migration of the target file. [0189] In step S 145 , the file replication/migration subprogram 1133 deletes node information of the storage node registered in the storage destination node candidate list from the node list information stored in the temporary area (S 145 ). Then, the process returns to the step S 142 . [0190] In step S 150 , the file replication/migration subprogram 1133 becomes an error as storage destination nodes cannot be found. In this case, the process is finished (S 150 ). [0191] FIG. 12 is a flowchart of the file access process carried out by the file access subprogram 1134 according to the first embodiment of this invention. [0192] The file access process is executed by a storage node (here, referred to as storage node A 1100 ) which requests access when an access request of a shared file (hereinafter, referred to as target file) registered in the overlay network is received. [0193] First, the file access subprogram 1134 searches for a target file of an access request to create a list of nodes in which the target file is present (S 161 ). For the searching of the target file, the query request control subprogram 1126 selects a plurality of arbitrary storage nodes from the node management table 4000 to ask whether the target file is present in the plurality of selected storage nodes. For a method of selecting storage nodes, for example, a method of randomly selecting a plurality of storage nodes is available. [0194] The query response control subprogram 1127 of the storage node (target node) selected in the step S 161 receives a query request to check whether the target file is present, and transmits its result as a response to the storage node A 1100 . If the target file is present, the query response control subprogram 1127 of the target node transmits the response together with information of metadata of the target file to the storage node A 1100 . [0195] The file access subprogram 1134 judges whether a target file has been found based on the response received from the target node in the step S 161 (S 162 ). [0196] If a target file has not been found, the file access subprogram 1134 judges that a target file of an access request has not been found. In this case, the process proceeds to step S 169 . [0197] On the other hand, if a target file has been found, the file access subprogram 1134 has to judge whether access can be requested to the target file. In this case, the process proceeds to step S 163 . [0198] The file access subprogram 1134 obtains information of access permitted/denied location of the target file (S 163 ). Specifically, the file access subprogram 1134 refers to the shared file metadata management table 4200 of the target file to obtain information of access permitted location 4230 and information of access denied location 4240 . [0199] The file access subprogram 1134 obtains information (presence location information) of a location (e.g., location where the client node 2000 is installed) where an access requester of the target file is present (S 164 ). [0200] A method of obtaining information of the location where the access requester is present is, for example, a method of using location information of a controller (e.g., storage node A 1100 ) which has first received an access request from the access requester. Alternatively, a method in which the controller uses positional information obtained by a GPS as information of a presence location of the access requester may be used. Otherwise, a method in which a third party (e.g., authentication server 3000 ) authenticates a presence location at the time of an access request of the access requester, and an authentication result is used may be employed. [0201] The file access subprogram 1134 judges whether the information of access denied location 4240 of the target file contains presence location information of the access requester (S 165 ). Specifically, the file access subprogram 1134 refers to the information of access denied location 4240 stored as metadata of the target file in the shared file metadata management table 4200 to judge whether a location indicated by the information of access denied location 4240 contains presence location information of the access requester obtained in the step S 164 . [0202] If the presence location information of the access requester is contained, the file access subprogram 1134 judges that access of the access requester to the target file is not permitted. In this case, the process proceeds to step S 168 . [0203] On the other hand, if the presence location information of the access requester is not contained, the process proceeds to step S 166 . [0204] The file access subprogram 1134 judges whether the information of access permitted location 4230 of the target file contains the presence location information of the access requester (S 166 ). Specifically, the file access subprogram 1134 refers to information of access permitted location 4230 stored as metadata of the target file in the shared file metadata management table 4200 to judge whether a location indicated by the information of access permitted location 4230 contains the presence location information of the access requester obtained in the step S 164 . [0205] If the presence location information of the access requester is not contained, the file access subprogram 1134 judges that access of the access requester to the target file is not permitted. In this case, the process proceeds to step S 168 . [0206] On the other hand, if the presence location information of the access requester is contained, the file access subprogram 1134 judges that access of the access requester to the target file is permitted. In this case, the process proceeds to step S 167 . [0207] The file access subprogram 1134 selects an arbitrary storage node from the list of nodes created in the step S 161 , and provides information of the selected storage node to the access requester. Then, the access requester accesses the storage node included in the provided information (S 167 ). [0208] For a method of selecting an arbitrary storage node, for example, a method of randomly selecting a storage node from the list of nodes created in the step S 161 is available. Alternatively, a method of selecting a storage node closest to the access requester may be used. Otherwise, a method of selecting a storage node of shortest access time from the list of nodes may be used. [0209] In step S 168 , as the file access subprogram 1134 judges that access to the target file is not permitted, the process is set as an error without permitting the access requester to access the target file (S 168 ). In this case, the process is finished. [0210] In step S 169 , as the file access program 1134 cannot find a target file, the process is finished as an error (S 169 ). [0211] The first embodiment of this invention has been described by way of the system for storing the shared file. However, the system may share and store, for example, data, information of a block unit, fixed length data, and a record in addition to the file. [0212] According to the first embodiment of this invention, the storage node for storing the shared file can be designated for each shared file. Thus, by suppressing storage of the shared file in a storage node installed in a location not permitted to store the shared file, unnecessary communication can be removed, and wasteful storage use can be suppressed. Moreover, since a location for accessing the shared file can be designated for each shared file, access from a location where access is not permitted can be denied. [0213] The first embodiment of this invention has been described by way of a configuration made by the storage node (controller). In addition, however, the embodiment can be configured as a control system or a control method. The first embodiment can be realized by various modes such as a computer program for realizing the storage node (controller), a recording medium for recording a program, and a data signal containing a program and realized in a carrier wave. [0214] In the case of configuring the embodiment of this invention as a computer program or a recording medium for recording a program, it can be configured as a controller or an entire program for controlling the controller. Only modules which perform functions of the first embodiment may be provided. As a recording medium, for example, a flexible disk, a CD-ROM, a DVD-ROM, a punch card, a printed matter where codes such as barcodes have been printed, or various volatile or nonvolatile storage media readable by an internal or external storage system of a computer can be used. Second Embodiment [0215] According to the first embodiment, based on the system configuration shown in FIG. 1 , the access to the shared file is controlled based on the storage destination node of the shared file and the presence location of the access requester. A second embodiment is directed to control for optimizing communication charges of a network. Description of modules of the second embodiment similar to those of the first embodiment will be omitted. [0216] FIG. 13 illustrates a configuration of a system according to the second embodiment of this invention. [0217] A difference from the first embodiment is that management servers 3100 , 3200 , 3300 , 3400 , and 3500 are coupled to ISPs. [0218] The management server 3100 provides information regarding network services provided by the ISP, and information regarding communication charges. The management servers 3200 , 3300 , 3400 , and 3500 have similar configuration to the management server 3100 . In the system shown in FIG. 13 , one management server is coupled to one ISP. However, a plurality of management servers may be coupled. [0219] FIG. 14 illustrates a hardware configuration of the management server 3100 according to the second embodiment of this invention. [0220] The management server 3100 includes a processor 3110 , a memory 3120 , an external storage system I/F 3140 , and a network I/F 3150 . These components are intercoupled via a bus 3160 . The management server 3100 is coupled to an external storage system 3170 via the external storage system I/F 3140 . [0221] The processor 3110 executes a program stored in the memory 3120 to control the entire management server 3100 . [0222] The memory 3120 temporarily stores the program executed by the processor 3110 and/or data. The memory 3120 may include, for example, a semiconductor memory such as a RAM. [0223] The memory 3120 stores an external storage system I/F control program 3121 , a network I/F control program 3122 , a local file system control program 3123 , a distributed file system management program 3125 , an ISP information management table 4300 , and a cache memory 3130 . [0224] The external storage system I/F control program 3121 controls the external storage system I/F 3140 . The network I/F control program 3122 controls the network I/F 3150 . [0225] The local file system control program 3123 contains a cache memory control subprogram 3124 . The local file system control program 3123 controls a file system provided by the management server 3100 . The cache memory control subprogram 3124 controls the cache memory 3130 . [0226] The distributed file system management program 3125 contains a query request control subprogram 3126 , a query response control subprogram 3127 , a basic control subprogram 3131 , and a file registration subprogram 3132 . [0227] The distributed file system management program 3125 manages information regarding network services provided by the ISP, and information regarding communication charges. [0228] The query request control subprogram 3126 controls a query request transmitted to the other management server constituting the overlay network. [0229] The query response control subprogram 3127 receives a query request from the other management server constituting the overlay network, executes a requested process, and controls a response of a processed result. [0230] The basic control subprogram 3131 manages information of the management server 3100 . For example, the basic control subprogram 3131 stores information (identification information) regarding the management server 3100 in the ISP information management table 4300 . [0231] The ISP information management table 4300 holds an ISP recognized by the management server 3100 , identification information of a management server present in the recognized ISP, and information regarding communication charges of a network for reaching the recognized ISP. The ISP information management table 4300 will be described later in detail referring to FIG. 15 . [0232] The cache memory 3130 is used for shortening access response time when access to a file managed by the file system is made. [0233] The external storage system I/F 3140 is an interface for accessing the external storage system 3170 . The network I/F 3150 is an interface for accessing the other system coupled via the network. [0234] The external storage system 3170 stores a program or user data. The external storage system 3170 may include, for example, a hard disk drive (HDD). Alternatively, a semiconductor memory device such as a flash memory may be used. [0235] FIG. 15 illustrates a configuration of the ISP information management table 4300 according to the second embodiment of this invention. [0236] The ISP information management table 4300 holds an ISP recognized by the management server 3100 , identification information of a management server present in the recognized ISP, and information regarding communication charges of the network for reaching the recognized ISP. [0237] The ISP information management table 4300 contains an ISP name 4310 , management server identification information 4320 of the ISP, and communication charges 4330 . [0238] The ISP name 4310 is information for identifying the ISP in the network. In the management server identification information 4320 of the ISP shown in FIG. 15 , information of a character string is stored. However, for example, information of a numerical value such as ID for identifying the ISP may be stored. [0239] The management server identification information 4320 of the ISP is identification information of the management server of the ISP coupled to a normal network. The management server identification information 4320 of the ISP is used for designating an access destination when access is made to the management server via the network. In the management server identification information 4320 of the ISP shown in FIG. 15 , an IP address is stored. However, for example, ID information for specifying the management server may be stored. Information of a character string may be stored. [0240] The communication charges 4330 are communication charges from an ISP network to which the management server 3100 itself is coupled to a network of an ISP to which a management server of a communication target is coupled. For the communication charges 4330 , the amount of money paid from one ISP to another is used. The amount of money to be paid by someone for facilities or operations may be used. [0241] In an example shown in FIG. 15 , five pieces of ISP information are stored. As an ISP name 4310 , ISP management server identification information 4320 , and communication charges 4330 of a first line of the ISP information management table 4300 , “ISP 1 ”, “ 10 . 20 . 30 . 200 ”, and “ 30 ” are respectively stored. These indicate that a management server named “ISP 1 ” is present in the network, the “ISP 1 ” can be accessed based on information of the destination “ 10 . 20 . 30 . 200 ”, and the amount of money indicated by the communication charges “ 30 ” has to be paid to access the “ISP 1 ”. [0242] Contents of the ISP information management table 4300 are updated by periodically exchanging information between the management servers. A method of updating the contents is similar to that of the flowchart of the node search process shown in FIG. 9 . In other words, the contents are updated by making inquiries about the contents of the ISP information management table 4300 to the other management server. [0243] FIG. 16 illustrates a configuration of the node management table 4000 according to the second embodiment of this invention. [0244] A difference from the first embodiment is that the node management table 4000 contains node communication charges 4030 . [0245] The node communication charges 4030 are communication charges generated when communication with a target storage node is carried out. The node communication charges 4030 are updated by taking updating of the contents of the node management table 4000 as an opportunity. Information regarding the communication charges is obtained by making an inquiry to a management server corresponding to the management server identification information 4140 of the node installation location information management table 4100 described later referring to FIG. 17 . A method of obtaining the information regarding the communication charges is similar to that of the flowchart of the node search process shown in FIG. 9 . In other words, the information is obtained by making an inquiry about communication charges to the other management server. [0246] In an example shown in FIG. 16 , as a node name 4010 , identification information 4020 , and node communication charges 4030 of a first line of the node management table 4000 , “STORAGE NODE A”, “ 10 . 20 . 30 . 40 ”, and “ 30 ” are respectively stored. These indicate that a storage node named “STORAGE NODE A” participating in the overlay network is present, the “STORAGE NODE A” can be accessed based on information of the destination “ 10 . 20 . 30 . 40 ”, and the amount of money indicated by the communication charges “ 30 ” has to be paid to access the “STORAGE NODE A”. [0247] FIG. 17 illustrates a configuration of the node installation location information management table 4100 according to the second embodiment of this invention. [0248] A difference from the first embodiment is that the node installation location information management table 4100 includes used ISP information 4130 and management server identification information 4140 of a used ISP. [0249] The used ISP information 4130 is information for identifying an ISP which provides network services to which the storage node is coupled. When the storage node uses a plurality of ISPs, a plurality of pieces of information for identifying the ISPs are stored. [0250] The management server identification information 4140 of the used ISP is identification information of a management server coupled to the ISP indicated by the used ISP information 4130 in the network. [0251] The used ISP information 4130 and the management server identification information 4140 of the used ISP are similarly stored when the node installation location information 4110 is stored. [0252] In an example shown in FIG. 17 , as the used ISP information and the management server identification information 4140 of the used ISP of the node installation location information management table 4100 , “ISP 2 ” and “ 10 . 100 . 30 . 200 ” are respectively stored. These indicate that an ISP for providing network services to be used by the storage node has a name “ISP 2 ”, and identification information of a management server belonging to the “ISP 2 ” is “ 10 . 100 . 30 . 200 ”. [0253] FIG. 18 is a flowchart showing a node search process according to the second embodiment of this invention. [0254] A difference from the first embodiment is that step S 117 is added between the steps 114 and 115 of FIG. 9 , and step S 118 is added after the step S 116 of FIG. 9 . [0255] In the step S 117 , the query response control subprogram 1127 of the target node makes an inquiry about communication charges to a management server of each ISP to reflect the charges in the node management table 4000 , based on the management server identification information 4140 of the node installation location information management table 4100 (S 117 ). [0256] If necessary information cannot be obtained only by the management server of an inquiry destination, the management server of the inquiry destination obtains information by sequentially asking the other management servers registered in the ISP information management table 4300 stored in its own server. [0257] In the step S 118 , the query request control subprogram 1126 of the storage node A 1100 makes an inquiry about communication charges to a management server of each ISP. The basic control subprogram 1131 of the storage node A 1100 reflects the communication charges obtained from the management server of each ISP in the node management table 4000 (S 118 ). Then, the process is finished. [0258] FIG. 19 is a flowchart showing a file access process according to the second embodiment of this invention. [0259] A difference from the first embodiment is that step S 170 is executed in location of the step S 167 of FIG. 12 . [0260] In the step S 170 , the file access subprogram 1134 selects a node of lowest node communication charge from the list of nodes created in the step S 161 , and provides information of the selected storage node to an access requester. Then, the access requester accesses the storage node whose information has been provided (S 170 ). [0261] According to the first embodiment, the access destination of the target file is arbitrarily decided. According to the second embodiment, however, the storage node of low communication charges can be selected. Thus, by executing control to preferentially access a shared file of a storage node whose communication charge is lowest, communication charges for file share services can be reduced. [0262] While the present invention has been described in detail and pictorially in the accompanying drawings, the present invention is not limited to such detail but covers various obvious modifications and equivalent arrangements, which fall within the purview of the appended claims.

Provided is a controller in a computer system, the computer system including a plurality of data storage systems, and at least one controller for controlling access to data stored in the plurality of data storage systems, the each controller including: an interface coupled to the network; a processor coupled to the interface; and a storage unit coupled to the processor, in which: the storage unit holds attribute information indicating whether to permit access to the data; and the processor is configured to: receive a writing request of the data from a client computer coupled to the network; judge whether each of the each controller permits the requested writing based on the held attribute information and information of a location where the each controller is installed; and write the data in a data storage system controlled by a controller judged to permit the writing.

PRIORITY CLAIM [0001] This application claims the benefit of U.S. Provisional Application No. 60/879,257, filed 8 Jan. 2007. GOVERNMENT INTEREST [0002] The claimed invention was made in the performance of work under a NASA contract, and is subject to the provisions of Public Law 96-517 (35 USC 202) in which the Contractor has elected to retain. FIELD [0003] The present invention relates to fuel cells. BACKGROUND [0004] FIG. 1 illustrates a high-level system diagram of a prior art direct methanol fuel cell operating on an aqueous feed of methanol. Neat (100%) methanol is stored in container 102 and then diluted with water to a concentration of 2-3% before it is introduced into fuel cell stack 104 . The methanol fuel solution is re-circulated, indicated by the loop comprising flow line 106 , gas and liquid separator 108 , radiator 110 and bypass 112 , pump 114 , mixer 116 , methanol sensor 118 , and cold-start heater 120 . Methanol is added to the solution by way of pump 114 and mixer 116 as needed to maintain the required concentration delivered to anode 122 . The fuel solution entering anode 122 is accurately monitored and controlled using methanol sensor 118 . [0005] The water used for this dilution is gathered at cathode 124 , flows through flow line 126 to sump tank 128 , and is pumped by sump pump 130 to gas and liquid separator 108 . Carbon dioxide is generated at and removed from anode 122 , as indicated by flow line 132 . [0006] Diluting methanol, collecting and circulating water, circulating fuel, and controlling concentration entail the use of several pumps and control systems, with their resulting use of electrical energy, and add to the size and cost of the fuel cell system. These auxiliary components may constitute about 50% of the overall volume and mass of present state-of-art direct methanol fuel cell systems, and may contribute to at least 50% of the parasitic energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS [0007] FIG. 1 illustrates a prior art fuel cell system. [0008] FIG. 2 illustrates a fuel cell according to an embodiment. [0009] FIG. 3 illustrates a fuel cell system according to an embodiment. [0010] FIG. 4 illustrates dependence of current density upon membrane thickness for an embodiment. [0011] FIG. 5 illustrates an anode electrode according to an embodiment. DESCRIPTION OF EMBODIMENTS [0012] In the description that follows, the scope of the term “some embodiments” is not to be so limited as to mean more than one embodiment, but rather, the scope may include one embodiment, more than one embodiment, or perhaps all embodiments. [0013] These letters patent teach the design of a direct methanol fuel cell in which back diffusion of water from the cathode to the anode in a methanol fuel stack is high enough so that water need not be collected at the cathode, and neat methanol may be provided to the anode without the need for dilution. By not requiring the gathering of water at the cathode, or the dilution of neat methanol, it is expected that embodiments may have reduced parasitic energy losses, higher power density, and higher reliability at reduced cost, compared to the prior art direct methanol fuel cell system of FIG. 1 . [0014] FIG. 2 illustrates an embodiment fuel cell 200 , and some of the processes involved. During fuel cell operation neat methanol (CH 3 OH) is oxidized at anode 202 to protons and carbon dioxide, and oxygen (O 2 ) is reduced to water at cathode 204 . As protons migrate from anode 202 to cathode 204 by way of membrane 206 , water is transported with the protons (H + ), as indicated by arrow 208 . This process is termed electro-osmotic drag, in which water molecules associated with the protons are dragged across membrane 206 in the direction of ionic movement. [0015] Water is consumed at anode 202 by the oxidation of methanol, and water is produced at cathode 204 by reduction of oxygen. Air flowing across cathode 204 evaporates some of this water. The remaining water generated at cathode 204 , as well as the water arriving at cathode 204 due to electro-osmotic drag, is brought to anode 202 by to back diffusion, as indicated by arrows 208 and 210 . [0016] It is useful to understand the factors that govern the rates of various water transport processes. The rate of consumption of water at anode 202 is determined by the current density, and for some embodiments, one mole of water is consumed for every 6 Faradays of electricity. The rate of migration of water from anode 202 to cathode 204 by electro-osmotic drag is determined by the current density and the drag coefficient. The some embodiments, the drag coefficient is about 3 molecules of water per proton. The rate of production of water at cathode 204 by reduction is also determined by the current density, and for some embodiments is given by 0.5 mole of water for every Faraday of electricity. [0017] The flow rate of air over cathode 204 , the temperature of fuel cell 200 , and the absolute humidity of air at the specified temperature determine the rate of evaporative loss. The concentration gradient of water between anode 202 and cathode 204 , and the diffusion coefficient of water in the membrane-electrode composite ( 206 ) determine the rate of back-diffusion. Accordingly, the rate of back diffusion may be increased by increasing the concentration gradient for water, and this process may be relatively independent of the current density. [0018] Thus, the rate of back diffusion to move water from cathode 204 to anode 202 that has not been removed due to evaporation may be achieved by appropriately choosing the concentration of methanol, the porosity of the electrodes in anode 202 and cathode 204 , the thickness of membrane 206 , the operating temperature of fuel cell 200 , and the stoichiometric rate of airflow over cathode 204 . For any given set of conditions for the foregoing variables, there will be a current density at which water balance will be achieved. Water balance means that the back diffusion rate and evaporative rate at cathode 204 are such that water does not accumulate at cathode 204 . [0019] Calculations have shown that when about 1 molar (3%) methanol solutions are circulated past anode 202 , the rate of back diffusion is inadequate to transport the water for a practical value of current density, and the current density at which water balance is achieved is quite low to be of practical value for most applications. However, when neat (100%) methanol is used, the back diffusion process alone is expected to achieve the water balance at a current density of 170 mA/cm 2 (mill-Ampere per square cm). This latter value of current density is expected to be in the range useful for practical applications. [0020] More specifically, calculations show that for a membrane thickness of 0.0635 cm, a stoic rate for air flow over cathode 204 of 3.0, a drag coefficient of 3.0 water molecules for each proton (H + ) transported by electro-osmotic drag, a temperature of 45° C., and a diffusion coefficient for water of 8.16*10 −6 cm 2 /sec; water balance is achieved for a methanol concentration of 3% at a current density of only 7 mA/cm 2 , but water balance is achieved using neat methanol according to an embodiment at a useful current density of 170 mA/cm 2 . [0021] Thus, the above description teaches that by using neat methanol and designing the fuel cell such that water is returned to the anode by back diffusion from the cathode, a practical current density may be achieved, and mechanical means for collecting and returning water may be avoided. FIG. 3 illustrates an embodiment, where neat methanol stored in container 302 is pumped by pump 304 to delivery system 306 . Delivery system 306 provides neat methanol directly to anode 202 , and fuel cell 300 is designed so that the back diffusion of water is sufficient so that water need not be removed at cathode 204 , other than by evaporation. An embodiment for delivery system 306 is described later. [0022] For some embodiments, membrane 206 may comprise Nafion. Nafion is a sulfonated tetrafluorethylene copolymer, and is a registered trademark of E. I. Du Pont de Nemours and Company, a corporation of Delaware. For such embodiments, membrane 206 is hydrophilic, and may for some embodiments allow water retention of up to about 40% of the membrane mass. Also, for some embodiments, water and carbon dioxide is produced by direct reaction of methanol with oxygen at anode 306 or cathode 204 , so that an adequate supply of water may be produced. [0023] If anode 202 , cathode 204 , or both are not capable of sustaining desired current densities due to slow catalysis or mass transport of reactants, then the electrode structures for anode 202 or cathode 204 , and the thickness of membrane 206 , may be adjusted so that an acceptable current density value may be achieved. An example is illustrated by FIG. 4 . [0024] FIG. 4 illustrates a functional relationship between fuel cell current density (mA/cm 2 ) and membrane thickness (cm) for the following fuel cell parameters: a stoic air flow rate of 3.0; a drag coefficient of 3.0 water molecules per proton; and a diffusion coefficient for water of 8.16*10 −6 cm 2 /sec. As noted in FIG. 4 , reducing the membrane thickness may lead to an increase in current density. For example, whereas a membrane thickness of 0.2 cm provides for a current density of about 46 mA/cm 2 , reducing the membrane thickness to 0.06 cm provides for a current density of about 170 mA/cm 2 . [0025] The presence of an uncontrolled excess of neat methanol at anode 202 may result in swelling of membrane 206 , which may lead to permanent damage of the membrane-electrode assembly. Accordingly, for some embodiments, the delivery rate of methanol to anode 202 should be such that only a relatively small quantity of methanol reaches the anode electrode. Furthermore, for some embodiments, the entire quantity of neat methanol that is delivered to the anode electrode should be utilized within the electrode structure, but the neat methanol should not reach the surface of membrane 206 in any significant quantity. [0026] Full utilization of neat methanol at the anode electrode may be achieved if the electrode structure is modified to be porous and thick, so that the residence time for methanol is adequate for complete consumption in the body of the electrode structure. For some embodiments, such a porous electrode should have enough ionomer material to form conducting paths for the protons and water, but have the enough tortousity to assure a high residence time. [0027] An ionomer is a polyelectrolyte comprising copolymers. For some embodiments, the electrode structure may have layers of varying ionomer content so that the desired level of utilization may be achieved. The thickness, layer design, and porosity of the electrodes may depend on the delivery rate. FIG. 5 illustrates in a simplified pictorial form anode electrode 502 and membrane 503 . Anode electrode 502 comprises carbonaceous substrate 504 and electrocatalyst layer 506 . Ionomer material is impregnated into carbonaceous substrate 504 to form varying layers of ionomer material 508 , 510 , 512 , and 514 . [0028] For some embodiments, the optimization of the electrode structure should be done in conjunction with the delivery method for the neat methanol. For some embodiments, delivery system 306 for delivering the neat methanol to anode 202 may be an aerosol delivery system as described in U.S. Pat. No. 6,440,594. As another example, for some embodiments, delivery system 306 may include a diffusion barrier of sufficient thickness. [0029] For some embodiments, the use of neat methanol at anode 202 and a back diffusion that provides water balance may involve the use of a modified fuel cell stack design that incorporates methods not only for fuel delivery but also for heat removal. For some embodiments, circulating feed 308 may be used, so that excess heat may be removed from anode 202 by way of radiator 310 . Heat may also be removed by evaporative cooling on cathode 204 . For some embodiments without circulating feed 308 , heat loss due to evaporation at cathode 204 may be augmented with heat removal by way of cooling fins 312 on the fuel stack. The design of such fins may depend on the power level and other resources available for cooling. [0030] Various modifications may be made to the described embodiments without departing from the scope of the invention as claimed below.

A fuel cell system running on direct neat methanol. Back diffusion of water from the cathode to the anode is sufficiently high so that water is not accumulated at the cathode, thereby leading to fuel cell systems without the need for a pump system to remove circulate water from the cathode to the anode. Other embodiments are described and claimed.

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a ferrule holder assembly for an apparatus for grinding end faces of a plurality of ferrules with optical fibers simultaneously. [0003] 2. Description of the Related Art [0004] It is well known by those skilled in the art that in order to connect optical fibers together while reducing connection loss and reflected returned light, tips of ferrules are ground by perpendicular or inclined spherical grinding to connect the optical fibers together. The shape of the convex spherical surface in this case is standardized by the international standard (IEC: International Electrotechnical Commission No. 60874-14-6) or the like. U.S. Pat. No. 5,351,445 discloses a technique of apparatus for grinding end faces of a plurality of optical fibers simultaneously. A ferrule holder of this grinding apparatus projects tips of ferrules from a plurality of insertion holes (sleeves) thereof to a grinding board by a specified amount and supports the ferrules. Grinding is performed by revolving a grinding film put on an elastic plate of the grinding board by an autorotational and orbital motion mechanism of the grinding apparatus and applying a specified amount of pressure to a grinding jig on which a plurality of ferrules with the optical fibers are mounted. Thus, the shape of the tips of the ferrules of the optical fibers can be made convex spherical surface that satisfies the standard. [0005] Even if a similar type of ferrule or connector is used, however, variation in length exists within a dimensional tolerance and the size differs depending on the manufacturer. Therefore, when a plurality of ferrules or connectors are mounted on the ferrule holder, it is difficult that all the tips of the ferrules are projected by a specified amount and supported. [0006] Although a reference plane of the ferrule holder for mounting the ferrule for grinding is processed to have a specified height with a strict tolerance, since the reference plane for mounting the plurality of ferrules is fixed, the heights of the tips of the ferrules from the insertion holes vary by an amount of variation in length of ferrules or housings of the ferrules. [0007] When the plurality of end surfaces of the optical fiber connectors of a lot in which the lengths of ferrules vary are simultaneously ground, since the grinding holder is directly weighted in the conventional grinding apparatus, problems occur in that the holder is tilted due to the variation in projection amount therefrom to generate a deviation from the shaft axis, or the ferrules having a small projection amount are insufficiently ground. Therefore, in the method of the conventional grinding apparatus, it is necessary to perform preliminary grinding up to a shortest ferrule and then to perform grinding again from a state in which the ferrules have the same height. SUMMARY OF THE INVENTION [0008] Accordingly, it is an object of the present invention to provide a ferrule holder assembly for an optical-fiber-end-face grinding apparatus in which the aforesaid problems of the variation in length of the housings of the ferrules can be solved. [0009] In order to achieve the above objects, a ferrule holder assembly for an optical-fiber-end-face grinding apparatus according to the present invention includes a ferrule holder board provided to be moved upward and downward in parallel with a grinding board of the optical-fiber-end-face grinding apparatus, a ferrule sleeve provided at the ferrule holder board for receiving and supporting an optical fiber ferrule while putting the tip thereof at the grinding board, an adapter for retaining the optical fiber ferrule or a connector for supporting the optical fiber ferrule in a state in which the optical fiber ferrule is inserted into the ferrule sleeve and urging means for urging the adapter in a direction to the grinding board from the ferrule holder board. [0010] The adapter retains and supports the optical fiber ferrule or the connector for supporting the optical fiber ferrule at the ferrule holder board in such a manner that the ferrule can be slid to the ferrule sleeve in the axial direction thereof, its revolution is restricted, and the downward movement limit is specified relative to said ferrule holder board. [0011] A retaining part of the adapter has a hook structure corresponding to a retaining member of a plug-type optical fiber connector housing. [0012] A retaining part of the adapter has a screw structure corresponding to a retaining member of a plug-type optical-fiber connector housing. [0013] The ferrule holder assembly for the optical-fiber-end face grinding apparatus is a ferrule holder assembly for an optical-fiber-end face grinding apparatus for inclined grinding, the attaching angle of said adapter is the same as that of the ferrule sleeve, and a guide key groove of the adapter is formed only at one side. [0014] The urging means is a coil spring and the force of the spring is smaller than the urging force of springs assembled to the connector plug itself. [0015] The means for urging the adapter to the holder is a coil spring and the weight is 550 gf or less appropriate for spherical grinding. The ferrule holder assembly for the optical-fiber-end-face grinding apparatus according to the present invention includes adapters in each of which the ferrule or the housing is fixed to a grinding-jig-plate main body thereof having a plurality of insertion holes penetrated for receiving the outside diameter of the tip of the ferrule. By pressing the adapter with a spring pressure, the ferrule with the optical fiber can apply a specified pressure toward a grinding board. [0016] In this case as well, although the heights of the tips of the ferrules from the plurality of insertion holes vary, the pressure of the tips of the ferrules to the grinding board can be almost the same by setting a spring constant of a spring that presses the adapter small in spite of the variation in the ferrules and the housing, and thereby the variation can be absorbed. Thus, the variation in the shape of the tips of the plurality of ferrules after grinding can be reduced. [0017] In addition, even in the inclined spherical grinding, the variation can be reduced by providing the insertion hole of the grinding-jig-plate main body in a manner so as to be inclined relative to the grinding surface, and also by inclining the adapter having a mechanism to be pressed by the spring pressure. [0018] The object to be ground is not limited to the ferrule, but various kinds of connectors can be applied depending on the design of the adapter. BRIEF DESCRIPTION OF THE DRAWINGS [0019] FIG. 1 is a plan view of an embodiment of a ferrule holder assembly for an optical-fiber-end-face grinding apparatus according to an embodiment of the present invention; [0020] FIG. 2 is a front view of the optical-fiber-end-face grinding apparatus on which the ferrule holder assembly shown in FIG. 1 is mounted; [0021] FIG. 3 is an enlarged view showing a state in which an SC-type optical fiber connector is attached to the embodiment of the ferrule holder assembly for the optical-fiber-end-face grinding apparatus shown in FIG. 1 ; [0022] FIG. 4 is an enlarged plan view showing a state in which an optical fiber connector is not connected to the embodiment of the ferrule holder assembly for the optical-fiber-end-face grinding apparatus shown in FIG. 1 ; [0023] FIG. 5 is an enlarged cross-sectional view showing a state in which the optical fiber connector is not connected to the embodiment of the ferrule holder assembly for the optical-fiber-end-face grinding apparatus shown in FIG. 1 ; [0024] FIG. 6 is a cross sectional view of another embodiment (for inclined grinding) of the ferrule holder assembly for the optical-fiber-end-face grinding apparatus according to the present invention; [0025] FIG. 7 is a cross sectional view showing a state in which a connector is connected to a still another embodiment (for grinding ferrules of an LC-type connector) of the ferrule holder assembly for the optical-fiber-end-face grinding apparatus according to the present invention; [0026] FIG. 8 is a cross sectional view of a further another embodiment (for grinding ferrules of an ST-type connector) of the ferrule holder assembly for the optical-fiber-end-face grinding apparatus according to the present invention; [0027] FIG. 9 is a cross sectional view of a still further another embodiment (for grinding ferrules of an FC-type connector plug) of the ferrule holder assembly for the optical-fiber-end-face grinding apparatus according to the present invention; and [0028] FIG. 10 is a cross sectional view of a yet further another embodiment (a ferrule with a flange) of the ferrule holder assembly for the optical-fiber-end-face grinding apparatus according to the present invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS [0029] Embodiments of the ferrule holder assembly for the optical-fiber-end-face grinding apparatus according to the present invention will be described hereinbelow with reference to the drawings. FIG. 1 is a plan view of an embodiment of the ferrule holder assembly for the optical-fiber-end-face grinding apparatus according to the present invention. Adapters 2 for supporting 20 units of connector ferrules, the number of which corresponds to the number of the connector ferrules, are arranged round a concentric circle on a ferrule holder board 1 having a generally square shape, in which a circular hole is provided at the center. This ferrule holder assembly for the optical-fiber-end-face grinding apparatus is mounted on the optical-fiber-end-face grinding apparatus as shown in FIG. 2 . A grinding apparatus main body 12 is provided with a grinding board 13 revolving on its axis and the orbit, on which a grinding film 14 is mounted. [0030] Holder retaining stands 15 are provided at the upper four corners of the grinding apparatus main body 12 , into which a holder retaining shaft 17 urged downwardly is respectively inserted in the center thereof. [0031] When the ferrule holder board 1 is mounted, levers of the holder retaining shafts are each rotated so as to apply a strong force. [0032] Holder-mounting reference surfaces 16 at the upper four surfaces of the holder retaining stands 15 are the same surface and are set to be parallel to a grinding surface of the grinding board. The height is set to L 2 (mm) from the grinding surface. The motion of the grinding board of the grinding apparatus is preferably a combined motion of the revolutions on its axis and the orbit; however, only an ordinary rotation is also possible. [0033] FIG. 3 is an enlarged view showing a state in which an SC-type optical fiber connector is attached to the embodiment of the ferrule holder assembly for the optical-fiber-end-face grinding apparatus shown in FIG. 1 . FIG. 4 is an enlarged plan view showing a state in which an optical fiber connector is not connected to the embodiment of the ferrule holder assembly for the optical-fiber-end-face grinding apparatus shown in FIG. 1 . FIG. 5 is an enlarged cross-sectional view showing a state in which the connector is not connected as well. As shown in FIG. 5 , recessed portions are formed in the ferrule holder board 1 , corresponding to each connector retaining position, and a ferrule sleeve 1 a of the holder board is provided at the center thereof, respectively. [0034] The adapter 2 has a quadrangular cylinder shape and is inserted into the recessed portion in a manner so as to enclose the ferrule sleeve 1 a as shown in FIGS. 4 and 5 . A pair of key grooves 2 b and 2 b facing each other are formed at the side of the adapter 2 . In addition, a pair of adapter hooks 2 a are provided at the inside of the adapter 2 , for retaining an SC-type connection plug that will be described later. An end of the adapter hook 2 a is inclined, and the adapter hook 2 a is elastically widened in response to insertion of the SC-type connection plug, and is then restored at a predetermined position to retain a plug body 11 of the SC-type optical fiber connector as shown in FIG. 3 . Part of the walls at the short sides of the adapter 2 are removed at the lower sides, and a pair of adapter flanges (spring bearings) 2 c for bearing a spring are provided thereat. A pair of adapter-spring pressing plates 4 are fixed to the ferrule holder board 1 using screws 6 in such a manner that the innermost ends of the plates overlie the upper sides of the pair of adapter flanges (spring bearings) 2 c . A pair of adapter springs 5 is inserted therebetween so as to urge the adapter 2 downwardly. [0035] A ferrule 9 of the SC-type optical fiber connector plug is inserted between a plug body 11 and a flange 9 a so as to be urged in a projecting direction by springs 10 . An optical fiber cord, the tip of which is adhered to the ferrule 9 , is led to the outside through a hood 7 covering the plug body 11 . The operator holds a connector housing (pick-up portion) 8 that is provided separately from the plug body 11 to perform attaching/detaching operations to the adapter. [0036] The plurality of optical fiber ferrules are attached to the embodiment of the ferrule holder assembly for the optical-fiber-end-face grinding apparatus shown in FIG. 1 , and circular cutout portions for positioning at four corners of the ferrule holder board 1 are adjusted to the holder retaining stands 15 of the grinding apparatus, and then the holders are each sufficiently tightened by the holder retaining shaft 17 by rotating the mounting lever. [0037] In this instance, if the projection amount L, of the ferrule from the lower end surface of the ferrule holder board 1 is set to an amount larger than a distance L 2 from the lower end surface of the ferrule holder board 1 to a surface of the grinding film, the tip of the ferrule is pressed up by the grinding film in a state in which the ferrule holder board 1 is tightened, and thereby the force of the adapter spring 5 is applied to the end face of the ferrule. Grinding is performed in this state. [0038] When the grinding amount is 0.1 mm or less, the grinding is possible where L 1 −L 2 >0.1 mm; however, the features of the present invention is that even when the length of the ferrules varies, there is no need for adjustment particularly. Assuming that the variation in the length of the ferrules is 0.2 mm, a grinding margin of 0.1 mm can be assured even for the shortest ferrule where L 1 −L 2 >0.3 mm. The force of the coil spring 5 applied to the adapter is preferably 550 gf or less in the case of spherical grinding using an elastic material plate as the grinding board, and the spring characteristic is preferably within the above-mentioned variation, having no influence on the force. [0039] The above-described embodiment is an example of perpendicularly grinding of the tip of the ferrule together with the optical fiber. The ferrule holder assembly for the-optical-fiber-end-face grinding apparatus for inclined spherical grinding of the tip of the ferrule can be provided. FIG. 6 is a cross sectional view of a ferrule holder assembly for the inclined grinding. A hole for inserting the adapter 2 is processed to be inclined corresponding to the grinding angle. The key groove 2 b for positioning in this case should be provided only at a predetermined side. [0040] FIG. 7 is a cross sectional view showing a state in which a connector is connected to another embodiment (for grinding the ferrule of an LC-type connector) of the ferrule holder assembly for the-optical-fiber-end-face grinding apparatus according to the present invention. An LC-type connector plug 20 is provided with a retaining hook lever 21 , and a projection provide at the lever 21 is engaged with a projection at the inner surface of the adapter 2 so as to fix the LC-type connector plug 20 to the ferrule holder board. An optical fiber cord (not shown) is led out through a hood 27 . In the drawing, description of the construction described previously with reference to FIG. 3 is omitted by giving common numerals or symbols. The same shall also apply to FIGS. 8, 9 , 10 . [0041] FIG. 8 is a cross sectional view of another embodiment (for grinding a ferrule of an ST-type connector plug) of the ferrule holder assembly of the optical-fiber-end-face grinding apparatus according to the present invention. The ST-type connector plug 30 is provided with a key pin 31 at the adapter 2 . The key pin has a cylinder 32 of the ST-type connector plug 30 connected thereto with a bayonet. [0042] FIG. 9 is a cross sectional view of another embodiment (for grinding a ferrule of an FC-type connector plug) of the ferrule holder assembly of the optical-fiber-end-face grinding apparatus according to the present invention. The FC-type connector plug 40 can be retained to the adapter with a box nut 42 . [0043] FIG. 10 is a cross sectional view of another embodiment (a ferrule with a flange) of the ferrule holder assembly of the optical-fiber-end-face grinding apparatus according to the present invention. This is a case of grinding the ferrule (a single body) 9 with the flange 9 a , which can be retained to the adapter with a box nut 51 . [0044] As described above in detail, in the grinding apparatus using the assembly according to the present invention, the projection amount of the ferrule is made the same in a state in which the assembly is attached to the grinding apparatus within a variation in the projection amount by disposing a separate spring to each adapter. That is, even if the lengths of the ferrules varies, grinding can be performed without preliminary grinding, and as a result, uniform grinding can be performed for a short time without unnecessary labor. In addition, attaching the connector to the adapter facilitates the attachment/detachment, resulting in an improved workability.

A ferrule holder assembly for an optical-fiber-end-face grinding apparatus comprises a ferrule holder board supported to be moved upward and downward in parallel with a grinding board of the optical-fiber-end-face grinding apparatus, a ferrule sleeve provided at the ferrule holder board for receiving and supporting an optical fiber ferrule while putting the tip at the grinding board, an adapter for retaining the optical fiber ferrule or a connector for supporting the optical fiber ferrule in a state where the optical fiber ferrule is inserted into the ferrule sleeve, and an urging unit for urging the adapter in a direction opposite to the grinding board from the ferrule holder board.

[0001] This application claims the benefit of the filing date of U.S. Provisional Patent Application No. 61/192,922 filed Sep. 23, 2008, the disclosure of which is hereby incorporated herein by reference. BACKGROUND OF THE INVENTION [0002] The invention relates to the installation of hatracks in a means of locomotion. In particular, the invention relates to a fastening device for installing a hatrack on a substructure of a means of locomotion, to a hatrack comprising a fastening device, to an aircraft comprising a hatrack, to the use of a fastening device in an aircraft, to a method for installing a hatrack to a fastening device, and to a method for deinstalling a hatrack from a fastening device. [0003] In present-day means of locomotion, for example in aircraft, omnibuses, rail vehicles or ships, hatracks are installed near ceilings of, for example, passenger cabins, which hatracks provide a means of storing items of baggage. These hatracks can mostly be closed by means of a flap so as to prevent these items of baggage or other objects held in the hatracks from falling from the hatrack, especially when the means of locomotion is in operation. [0004] Such hatracks are suitable for carrying considerable loads. The resulting considerable static forces and the considerable dynamic forces caused in operation are in the most direct possible way introduced to a structure that is suitable for this, for example frame elements and/or stringers of an aircraft fuselage. Furthermore, it can be possible to introduce these forces into a substructure, for example because the substructure provides more suitable attachment options for receiving the hatracks, wherein the substructure then in turn, as a rule, is directly connected to the frame elements and/or stringers. [0005] In order to attach the hatracks to the respective structures or substructures, the hatracks are mostly suspended from these structures either by means of screw-type connections or, as is common in aircraft construction, by means of so-called tie rods. Because technical operating equipment, for example cables or switches, can be located behind the hatracks, these hatracks are attached in a deinstallable manner. [0006] However, it has been shown that the installation and also the deinstallation of such hatracks can be time-consuming and labour-intensive. At least in aircraft construction, as a rule at least one first installer needs to position the hatrack to be installed, and at least one second installer needs to connect the hatrack by means of suitable connection materials to the corresponding structure or substructure. Thus, as a rule, at least two technicians are required to carry out the installation. [0007] Thus DE 10 2005 054 890 A1, which is also published as WO 2007/057191 A1, describes an attachment structure for fixing internal equipment components in a passenger cabin of an aircraft fuselage structure, which among other things is formed by frame elements that are arranged so as to be spaced apart from each other in longitudinal direction of the aircraft fuselage. DE 10 2006 016 509 A1, which has also been published as US 2007/0284479 A1, in turn describes a quick-release fastening system for mounting an element to a fastening structure. BRIEF SUMMARY OF THE INVENTION [0008] Accordingly, it is the object of the invention to state a simple and preferably detachable attachment of a hatrack to a structure or substructure, which attachment can preferably be carried out by means of only one installer. [0009] According to an exemplary embodiment of the invention, a fastening device for installing a hatrack to a substructure of a means of locomotion comprises a pre-locking device and a main locking device. In this arrangement, the pre-locking device is designed for automatic provisional affixation of the hatrack to the fastening device when the hatrack during an installation movement of the hatrack is moved in the direction of the fastening device. The main locking device is designed for final affixation of the hatrack to the fastening device. [0010] As a rule, the hatrack is an overhead bin that can preferably be closed by means of a hinged cover or a flap. [0011] By means of this arrangement, installation of the hatrack by only one technician is possible. In a first work step the technician moves the hatrack so that it engages the pre-locking device. From this point in time onwards the technician's hands are free because the hatrack is provisionally affixed so that in a second work step said technician can finally affix the hatrack, by means of the main locking device, to the fastening device or to the substructure. [0012] In addition, this arrangement ensures that deinstallation of the hatrack is also possible by means of only one technician. In this process the technician disengages the main locking device at the fastening device so that the hatrack is then only held by the pre-locking device. In the next work step the technician releases the pre-locking device and removes the hatrack from the fastening device. [0013] According to a further exemplary embodiment of the invention, the fastening device is provided for snap-and-click installation of the hatrack to the substructure of the means of locomotion. The fastening device comprises a fork head with a fork that is formed by two limbs, wherein each limb comprises an opening. Furthermore, the fastening device comprises a main bolt that constitutes the main locking device and that is movable, along its longitudinal direction of extension, between a locked position and an unlocked position, wherein the main bolt in the locked position is held in the openings of both limbs, and in the unlocked position is held only in the opening of one of the limbs. Furthermore, the fastening device comprises an eye that is designed such that in an installed state it can be received between the two limbs of the fork head, wherein the main bolt in the locked position engages the eye in such a way that the eye is connected to the fork head, and wherein the main bolt in the unlocked position completely releases the eye. Finally, the fastening device comprises a pre-locking device with a pressure member, wherein the pre-locking device on at least one of the limbs of the fork head is designed and arranged in such a way that the pressure member can be dislocated between a locking position and a release position and that when the main bolt is in the unlocked position and the pressure member is in the locking position, the eye rests in a pre-locking position on the pressure member, and that when the main bolt is in the unlocked position and the pressure member is in the release position the eye is completely released. [0014] A main aspect of the invention can be considered to be based on the following idea: [0015] The invention can bring about a situation in which a hatrack in an aircraft can be installed and deinstalled in a simpler manner, i.e. as already mentioned above, preferably by means of only one technician. To this effect a fastening device is proposed by means of which a storage bin can be installed in a snap-and-click manner to a retaining structure on a vehicle, wherein the hatrack can at first snap or click into a so-called pre-locking position in which said hatrack in its only lightly loaded state, for example empty state, is held to the retaining structure, and subsequently a main bolt can be slid into place, which main bolt can cause the actual force transmission to the retaining structure also in the heavily loaded state. Such a fastening device arrangement is at times also referred to as a snap-and-click fastening device arrangement. [0016] As a rule, the hatrack is attached to the structure or the substructure by means of four fastening devices. It is of no consequence whether it is the eye or the fork head that is attached to the hatrack, with the appropriate counter-part being attached to the structure. The advantages resulting from the fastening device according to the invention are to be explained with reference to installation and deinstallation, wherein the explanation is based on the fork head being attached to the structure, and the eye being attached to the hatrack. [0017] For installation of one of the hatracks the main bolt rests in the unlocked position thus releasing the entire width between the two limbs of the fork head. The pre-locking device is in the locking position so that the pressure member projects into the fork of the fork head. When the eye is led into the fork, the eye dislocates the pressure member at least to near the release position and reaches the locking position for the first time when an opening that is located in the eye reaches the pressure member, and for the second time when the eye has been moved completely beyond the pressure member. In this so-called pre-locking position the eye, or the hatrack attached to said eye, rests on or is held on the pressure member. This procedure is carried out on all the fastening devices. It may depend on the installation situation as to whether in a first installation step the eye on all the fastening devices is at first only inserted to such an extent that the pressure member of the pre-locking device moves into the opening of the eyes, thus securing the hatrack in this position, and in a second work step the hatrack is then guided on all the fastening devices right to the pre-locking position, or whether the hatrack on all the fastening devices by means of a single installation step is moved right to the pre-locking position. After the hatrack has reached the pre-locking position, the main bolt, which is in the unlocked position, is moved through the opening of the eye, which opening is now in front of the main bolt, and through the opening of the second limb into its locked position. This installation step ends the installation procedure. The main bolt, which is more strongly dimensioned when compared to the pressure member, takes up the static and dynamic forces that act on the hatrack during operation, and introduces said forces to the substructure by way of the fork head. In this arrangement, the substructure can be connected to the primary structure of the vehicle, either so as to be fixed or by means of tie rods. [0018] Reconfiguration, for example, of a passenger cabin in an aircraft, or carrying out repair and maintenance work may necessitate deinstallation of the at least one hatrack. [0019] In order to deinstall one of the hatracks, first the main bolt is moved from its locked position to the unlocked position. In the unlocked position the main bolt completely releases the eye. The eye then rests on the pressure member of the pre-locking device that is in the locking position. By moving the pressure member from the locking position to the release position, here again the eye is completely released. After this unlocking process has been completed, the eye can be removed from the fork of the fork head. After this deinstallation step has been carried out on all the fastening devices, the hatrack is no longer connected to the structure. This deinstallation step completes deinstallation of the hatrack. [0020] According to a further exemplary embodiment of the invention, on one end of the pressure member of the pre-locking device that is arranged on the fastening device, an inclined surface has been formed. In this arrangement the inclined surface has been designed in such a way that when the pre-locking device is in the locking position, the inclined surface makes it possible to slide the eye into the fork of the fork head while at the same time preventing withdrawal of the eye from the fork. Thus when the eye is pushed into the fork of the fork head, the pressure member is dislocated from its locking position at least to near the release position. The inclined surface thus points in the direction of slide-in of the eye. In order to ensure the function of the pressure member with the inclined surface, the pressure member can be arranged so that it is nonrotational relative to the fork of the fork head. [0021] According to a further exemplary embodiment of the invention, the pressure member of the pre-locking device that is arranged on the fastening device can be locked in the release position. This ensures that during deinstallation of the hatrack, when the main bolt is in the unlocked position and the eye is threaded from the fork of the fork head, the eye does not encounter any projections with which it can become wedged. [0022] According to a further exemplary embodiment of the invention, when the eye is in the pre-locking position, as a result of dislocation of the main bolt from the unlocked position through the eye and into the locked position, relief between the pressure member and the eye takes place. Thus the pre-locking device can be more lightly built when compared to the main bolt, because during installation or deinstallation the pre-locking device only needs to carry the weight of the empty hatrack, as a rule without dynamic effects, and ideally is only arranged on one of the two forks. In the locked position the main bolt is supported by both forks of the fork head. As a rule, all the static forces that act on the hatrack, in other words both the intrinsic weight of the hatrack and the additional load or payload, and the forces that dynamically act on the hatrack including the additional load, are introduced into the structure through the main bolt and the fork by way of the fork head. [0023] According to a further exemplary embodiment of the invention, the pressure member of the pre-locking device is pre-tensioned in the direction of the locking position. Thus, in order to move the pressure member from the locking position to the release position, the pressure member is dislocated against the direction of pre-tension. Thus when the eye during installation of the hatrack is guided into the fork of the fork head, the pressure member, as a result of its inclined surface, while generating an additional force at the eye, is pushed back against this direction of pre-tension. In a counter move, if no force acts on the inclined surface, as a result of pre-tension which as a rule is exerted by a spring, the pressure member is pushed into its locking position. Thus it can be ensured that the pressure member, when it is not in the release position, is in the locking position rather than taking up some undetermined intermediate position. Thus in particular during deinstallation of the hatrack, when the main bolt has been dislocated to the unlocked position, it can be ensured that the eye and the pre-locking position engage each other in such a way that unintended detachment of the eye and thus of the hatrack from the pre-locking position is impossible. [0024] According to a further exemplary embodiment of the invention, at least one of the facing interior walls of the limbs of the fork of the fork head comprises a groove in such a way that during installation the eye is guided by the groove into the pre-locking position. This ensures that the eye is inevitably guided into its pre-locking position. [0025] Advantageously both interior walls comprise grooves so that the eye is guided both on its front and on its rear. Double-sided guidance of the eye can ensure that in the pre-locking position both the front and the rear opening of the eye come to rest above the openings of the fork. This makes it easier, when the eye has reached the pre-locking position, to dislocate the main bolt from its unlocked position through the opening of the eye into its locked position. [0026] According to a further exemplary embodiment of the invention, at least one of the grooves comprises insertion aids. They can be arranged in such a way that in the region that first establishes contact with the eye the groove is inclined across the direction of insertion. This incline can considerably facilitate insertion of the eye into the groove since the eye is then quasi-caught by the insertion aid and guided to its final pre-locking position. There is thus largely no need to thread the eye into the groove. [0027] In a further exemplary embodiment of the invention, the limb of the fork of the fork head on which the pre-locking device is arranged comprises a main-bolt securing device that is dislocatable between an engaged position and a disengaged position, which main-bolt securing device, when the main-bolt securing device is in the engaged position secures the main bolt at least in either the locked position or the unlocked position. In this way it can be ensured that the main bolt, when it is thus subjected to loads by the hatrack with any additional items of baggage, remains in the locked position rather than, during operation, for example due to any vibration, independently moves in the direction of the unlocked position. [0028] Securing the retaining bolt in the unlocked position also ensures that when in addition the pre-locking device is in the release position, the eye can be freely moved within the fork. This can be useful so that when the hatrack or the eye, for example due to twisting or warping, cannot be released from the fork of the fork head, the technician who carries out deinstallation will know that s/he may apply more force to release the hatrack, without having to expect damage to the hatrack and/or to the fastener as a result of a projecting main bolt. [0029] In the engaged position the main-bolt securing device is pushed against the external contour of the main bolt, for example by a spring. In the disengaged position the main-bolt securing device completely releases the main bolt. [0030] According to a further exemplary embodiment of the invention, the main bolt comprises a flat part which the main-bolt securing device engages when the main bolt is in the locked position and the main-bolt securing device is in the engaged position, and wherein the main-bolt securing device being released as a result of the main bolt being rotated. This way of securing the main bolt ensures that by means of a rotational movement the main bolt can be dislocated from a secure position to a released position and from there to the unlocked position. In order to be able to carry out the rotary movement a securing device installed on the main bolt, which securing device can for example be a push button that is radially affixed to the main bolt in radial direction and that is resilient, is dislocated by the technician. When the main bolt is in the locked position the push button possibly snaps into an opening or into a groove of a sleeve that can be firmly connected to the limb of the fork of the fork head, which limb receives the pre-locking device, in order to, in the non-operated position, stop said rotary movement. This rotary movement and the subsequent pulling movement can be carried out with one hand; there is no need to use the second hand as well. Thus, in cases where deinstallation of the hatrack is carried out by only one technician, the hatrack can be supported with the second hand, for example in order to facilitate movement of the main bolt from the locked position to the unlocked position. [0031] Advantageously, one end of the main bolt is shaped in such a way that when the main-bolt securing device is in the engaged position the main-bolt securing device prevents dislocation of the main bolt beyond the unlocked position. This can substantially facilitate finding the unlocked position of the main bolt. The technician tasked with deinstalling the hatrack can dislocate the main bolt from the locked direction to the unlocked position until the main bolt can no longer be dislocated. The technician thus knows that when blocking of the main bolt during dislocation occurs the main bolt has reached the unlocked position. [0032] In order to be able to remove the main bolt, for example for service purposes, it is possible, for example, by means of an operating tool that is affixed to the main-bolt securing device, to dislocate the main-bolt securing device with one hand to the disengaged position in order to, with the other hand, dislocate the main bolt beyond the unlocked position. [0033] According to a further exemplary embodiment of the invention, the pre-locking device and the main bolt are to be dislocated in the same direction in order to reach the release position or unlocked position. Thus the technician charged with deinstalling the hatrack can operate from one side both the main bolt and the pre-locking device. This can make it considerably easier for the technician to carry out the work. [0034] According to a further exemplary embodiment of the invention, the fork head is connected to a base body that is firmly connected to the substructure in such a way that the fork head can be dislocated relative to the base body. Thus, for example, the various fork heads that are to be arranged on a common hatrack can be adjusted to any spacing that exists between the eyes that are firmly connected to the hatrack. In this way it is possible, for example, to compensate for production tolerances or to correct gap dimensions between the individual adjacent hatracks. Depending on the requirements and arrangement, dislocation can be carried out in the longitudinal- and/or transverse direction of extension of the hatrack. For dislocation in the longitudinal- and transverse direction of extension, the fork head can, for example, be connected to a cross adjustment device that comprises two adjustment devices with advantages as described in the following paragraphs. [0035] According to a further exemplary embodiment of the invention, the fastening device furthermore comprises two limbs that at least in partial regions are parallel, which limbs are connected to one side of the base body, wherein each limb comprises an opening, and wherein the two openings are aligned. Furthermore, the fastening device comprises an arbor that is rotatably held in the two openings. In addition there is a bush, between the limbs, with an external thread, wherein the bush is firmly connected to the arbor, and the bush is rotatable between the limbs without there being any play. The fork head comprises an internal thread such that the internal thread of the fork head engages the external thread of the bush. Furthermore, the fork head is designed such that by rotating the arbor the fork head can be dislocated between the limbs along the arbor. The connection between the arbor and the bush can, for example, take place by way of a clamping sleeve or a grooved pin. The hole that is required to accommodate the connection element can extend across the direction of longitudinal extension of the arbor. [0036] If a hatrack, is attached with, for example, three or four fastening devices to the substructure, possibly only two fastening devices are designed in the form described above. The remaining fastening device or fastening devices can be designed in such a way that the fork head can slide on the arbor between the limbs wherein the arbor being disconnectably connected to the limbs of the base body. This arrangement is, for example, achievable in that the fork head comprises a through-hole instead of an internal thread. Thus during installation of the hatrack the fork head of this fastening device adjusts the actual distance of the eyes attached to the hatrack. As a result of this the hatrack can on the one hand be installed without any tension, and on the other hand as a result of this arrangement, for example, any changes in length that occur during operation as a result of temperature differences or distortion can automatically be compensated for. [0037] According to a further exemplary embodiment of the invention, the arbor comprises two ends, wherein on one end a tool holding fixture and on the other end there is a blocking device that prevents independent rotation of the arbor. Thus, independent rotation of the arbor, after positioning of the fork head by rotating said arbor, during operation, for example as a result of vibration, is prevented. [0038] The tool holding fixture can, for example, be designed as a hexagonal head. [0039] The blocking device is, for example, designed as a spur-toothed gearwheel which is butt-joined to one end of the arbor, wherein a pre-tensioned pressure member protrudes between the teeth. During rotation of the arbor or of the gearwheel this pressure member is forced back against its direction of pre-tension, by a tooth face, and after overcoming the tooth presses between the adjacent pair of teeth due to pre-tension. The blocking device can also be designed in such a way that instead of a gearwheel, the edge of the arbor comprises, for example, knurling or a cylinder with radial holes, in which the pressure member engages the holes and in this way secures the selected setting of the fork head. [0040] According to a further exemplary embodiment of the invention, the fork head and the base body are designed so as to engage each other in such a way that forces from the fork head can be transferred to the base body. This ensures that rotary forces around the arbor do not result in the fork head rotating relative to the base body. On the one hand such forces can occur during the adjustment procedure during which the fork head is adjusted relative to the base body. On the other hand such forces can occur during operation while longitudinal forces and/or transverse forces acting on the hatrack manifest themselves in the above-mentioned torsional forces. These torsional forces can, for example, be introduced in the base body in that the fork head comprises a U-shape that extends along the internal thread and that is open in the direction of the base body, wherein the base body is located between the limbs that form the U-shape. Thus, during adjustment, the fork head is guided, by the U-shape, relative to the base body, by the arbor across the direction of extension of the arbor. [0041] According to a further exemplary embodiment of the invention, a hatrack is stated that comprises a fastening device as described above. [0042] According to a further exemplary embodiment of the invention, an aircraft with a hatrack described above is stated. [0043] According to a further exemplary embodiment of the invention, the fastening device according to the invention is used in an aircraft. [0044] All the characteristics that are described above and below in relation to the functional characteristics of the fastening device can also be implemented in the installation method and in the deinstallation method and vice versa. [0045] According to a further exemplary embodiment of the invention, a method for installation of a hatrack on a fastening device is provided. This method comprises movement of the hatrack in the direction of the fastening device, automatic provisional affixation of the hatrack by means of a pre-locking device, and final affixation of the hatrack by means of a main locking device. [0046] According to a further exemplary embodiment of the invention, a method for deinstalling a hatrack from a fastening device is stated. This method comprises releasing a main locking device, dislocating the hatrack from a final affixation position to a provisional affixation position, undoing the pre-locking device, and removing the hatrack from the fastening device. [0047] Further details and advantages of the invention are provided in the subordinate claims in conjunction with the description of an exemplary embodiment that is explained in detail with reference to the drawings. BRIEF DESCRIPTION OF THE DRAWINGS [0048] FIG. 1 shows a three-dimensional view of a fastening device according to an exemplary embodiment of the invention between a hatrack and a substructure; [0049] FIG. 2 shows an enlarged view of the fastening device from FIG. 1 ; [0050] FIG. 3 shows a three-dimensional view of the fastening device from FIG. 1 without the hatrack; [0051] FIG. 4 shows a three-dimensional view of the main bolt of a fastening device according to an exemplary embodiment of the invention; [0052] FIG. 5 shows a three-dimensional view of a pre-locking device of a fastening device according to an exemplary embodiment of the invention; [0053] FIG. 6 shows a dislocation arrangement of a fastening device according to an exemplary embodiment of the invention for dislocating a fork head relative to a base body; [0054] FIG. 7 shows a blocking device of an arbor of the dislocation arrangement shown in FIG. 6 ; and [0055] FIG. 8 shows the fastening device from FIG. 3 with an attachment part of the hatrack. DETAILED DESCRIPTION [0056] It should be mentioned that identical components in the figures have the same reference characters and that the drawings are only diagrammatic and not necessarily to scale. [0057] FIG. 1 shows a fastening device 2 between a hatrack 4 and a substructure 6 that is formed by a U-shaped profile. The substructure 6 is connected to a primary structure by means of tie rods 8 , with the primary structure in the present example being formed by frame elements 10 of an aircraft. [0058] FIG. 2 shows an enlarged view of the fastening device 2 from FIG. 1 . The fastening device 2 in its principle constituents comprises an attachment plate 12 that is connected to the hatrack 4 , with a web 14 being formed to the attachment plate 12 , which attachment plate 12 in the centre receives an eye 16 . The eye 16 is located between a left-hand limb 18 and a right-hand limb 20 , which together form a fork 22 . The fork 22 forms part of a fork head 24 . In the installed state the hatrack 4 is held by a main bolt 26 that detachably attaches the eye 16 between the two limbs 18 , 20 . By means of an arbor 28 the fork head 24 is connected to a base body 30 . The base body 30 in turn, by means of connection elements (not shown) is attached to the substructure 6 . [0059] FIG. 3 shows the fastening device 2 in the installed position without the hatrack 4 and without the eye 16 that engages the region between the two limbs 18 , 20 . The main bolt 26 is in a locked position. In this arrangement the main bolt 26 is held both in a transverse hole 32 of the left-hand limb 18 and of the right-hand limb 20 . The interior walls 34 , 36 of the two limbs 18 , 20 each comprise a rectangular groove 38 that is open in the direction of insertion E. The rectangular groove 38 comprises a groove bottom 40 that is delimited by a groove wall 42 , which groove bottom 40 extends parallel to the interior wall 34 , 36 . Furthermore, the groove 38 , at its edge 44 facing the direction of insertion E, comprises an insertion aid 46 . The insertion aid 46 comprises an inclined insertion surface 48 by means of which the depth of the groove 38 is increased relative to the interior wall 34 , 36 , as well as an inclined insertion surface 50 that increases the space between the groove walls 42 that face each other in a limb 18 , 20 and the edge 44 . [0060] In the right-hand limb 20 , furthermore, there is a main-bolt securing device 52 which pushes onto a flat part 54 of the main bolt 26 . The pre-tension with which the main-bolt securing device 52 pushes onto the main bolt 26 is adjustable. Furthermore, in the right-hand limb 20 there is a pre-locking device 56 . This pre-locking device 56 is arranged in the right-hand limb 20 in such a way that the directions of longitudinal extension of the main bolt 26 and of the pre-locking device 56 extend parallel. Furthermore, the pre-locking device 56 is located below the main bolt 26 when viewed in the direction of insertion E. [0061] On the side facing the direction of insertion E the base body 30 comprises two limbs 58 that extend parallel to each other. Each limb 58 comprises a transverse hole 60 whose position is flush relative to each other. In the two transverse holes 60 the arbor 28 is rotatably held. At one end the arbor 28 comprises a hexagonal head 62 to receive an operating tool, for example a matching hexagonal spanner or wrench. On the other end of the arbor 28 a blocking device 64 is arranged. This comprises a spur-toothed gearwheel 66 that is firmly butt-joined to the arbor 28 and further comprises a locking element 68 that in a pre-tensioned manner projects between two adjacent teeth of the gearwheel 66 . [0062] FIG. 4 shows the main bolt 26 of the fastening device 2 in the locked position. In this arrangement there is an operating knob 70 on the end of the main bolt 26 , which end faces the right-hand limb 20 . The end opposite the operating knob 70 shows a circumferential groove 72 in the main bolt 26 . When viewed from the direction of the operating knob 70 , there is a projection 74 behind the groove 72 , which projection 74 is firmly connected to the main bolt 26 . Behind the projection 74 a cone 76 is arranged. Furthermore, a sleeve 120 is firmly connected to the right-hand limb 20 , which sleeve 120 extends in the direction of longitudinal extension of the main bolt 26 in the direction of the operating knob 70 . Crossing the insertion direction E, in the sleeve 120 there is an opening 122 in the form of a groove. A sprung push button 124 projects into this groove 122 , which push button 124 is firmly connected to the main bolt 26 . In addition, an operating device 126 is formed to the main-bolt securing device 52 . By means of the operating device 126 the main-bolt securing device 52 , which is in an engaged position, can be dislocated to a disengaged position, without it being possible for the main-bolt securing device 52 to be affixed in this disengaged position. [0063] When the main bolt 26 is dislocated from its locked position to its unlocked position, to this effect one hand pushes the push button 124 against the spring force into the main bolt 26 until the push button 124 no longer engages the opening 122 . Subsequently the same hand rotates the operating knob 70 of the main bolt 26 until the main securing bolt 52 no longer engages the flat part 54 . In this rotated position the main bolt 26 can be dislocated to the unlocked position. In the unlocked position the main securing bolt 52 engages the groove 72 , and in this position secures the main bolt 26 . Further withdrawal of the main bolt 26 leads to the main-bolt securing device 52 running against the projection 76 which then prevents the main bolt from being able to be pulled out any further from the right-hand limb 20 . When the main bolt 26 is in its unlocked position, the bolt is pulled back far enough for the highest point 78 of the cone 76 to be either flush with the groove bottom 40 of the right-hand limb 20 or to be further back relative to the groove bottom 40 , in the direction of the operating knob 70 . [0064] In order to remove the main bolt 26 , the main-bolt securing device 52 is dislocated to the disengaged position by means of the operating device 126 . The main bolt 26 can now be dislocated beyond the unlocked position. [0065] To dislocate the main bolt 26 from the unlocked position to the locked position, the main bolt 26 is dislocated until the push button 124 comes to rest in the opening 122 as shown in FIG. 4 . In this locked position the main-bolt securing device 52 engages the flat part 54 , and engagement of the push button 122 with the opening 124 prevents relative rotation of the main bolt 26 relative to the fork head 24 . Since the position of the push button 124 and thus of the main bolt 26 relative to the limb 20 is visible to the installing technician, said technician can thus also check that the main bolt 26 is secured by the main-bolt securing device 52 . [0066] When viewed from the direction of insertion E, underneath the main bolt 26 there is the pre-locking device 56 , which is described in detail in the following figure. [0067] FIG. 5 shows the pre-locking device 56 that is located in the right-hand limb 20 . The pre-locking device 56 essentially comprises a sleeve 80 with an elongated hole 82 , a pressure member 84 with an inclined surface 86 and a handle 88 that is firmly connected to the pressure member 84 , as well as a spring 90 . The inclined surface 86 arranged on the pressure member 84 points against direction E. The pressure member 84 is kept in a locking position in that the spring 90 pushes onto the end of the pressure member 84 , which end is opposite the inclined surface 86 , thus keeping said pressure member under pre-tension in the locking position. In order to prevent rotation of the pressure member 84 and thus rotation of the inclined surface 86 , the handle 88 extends in the elongated hole 82 . The elongated hole 82 in turn extends along the direction of longitudinal extension of the sleeve 80 on the side facing direction E. [0068] The pressure member 84 can be dislocated to a release position. To this effect the pressure member 84 is dislocated against the spring force F until the foremost point of the inclined surface 86 extends so as to be either flush with the groove bottom 40 or to be further back, relative to the groove bottom 40 , against the direction F. In order to be able to lock the pressure member 84 in the release position, the handle 88 can be inserted into the circumferential groove 92 . [0069] FIG. 6 shows a dislocation arrangement for dislocating a fork head 24 relative to a base body 30 . As already mentioned at an earlier point in time, the arbor 28 is held in the transverse holes 60 of the two limbs 58 . Between the limbs 58 a bush 94 is held without any play but in a rotatable manner, through the central hole (not shown) of which bush 94 the arbor 28 extends. On its outside the bush 94 comprises an external thread 96 . The bush 94 is connected to the arbor 28 in such a way that across the direction of longitudinal extension of the arbor 28 there is a transverse hole 98 that is flush with the bush 94 , through which transverse hole 98 a clamping sleeve 100 is installed in such a way that it firmly connects the bush 94 to the arbor 28 , while its ends are further back relative to the thread root 102 of the external thread 96 . In order to install the clamping sleeve 100 there is a correspondingly placed through-opening in the fork head 24 . The external thread 96 engages an internal thread 104 that has been made in the fork head 24 . At its end facing the direction of insertion E the fork head 24 is U-shaped with two limbs 106 whose interior is supported by the base body 30 . [0070] By rotation of the arbor 28 on the hexagonal head 62 the bush 94 is rotated, and with it the external thread 96 that has been cut onto the bush 94 . Consequently the internal thread 104 moves with the fork head 24 relative to the external thread 96 . In addition, the fork head 24 is supported, by way of its two limbs 106 , on the base body 30 . These limbs 106 prevent a situation in which torsional forces, which can be generated either during adjustment as a result of possible friction in the thread 96 , 104 or during operation as a result of longitudinal forces or transverse forces which may be generated by the hatrack 4 (not shown), can lead to rotation of the fork head 24 relative to the base body 30 . [0071] To prevent a situation in which the arbor 24 independently rotates during operation, this is effectively prevented by the blocking device 64 described in detail in the next figure. [0072] FIG. 7 shows the blocking device 64 that acts on the end of the arbor 24 , which end is opposite the hexagonal head 62 . In this arrangement the spur-toothed gearwheel 66 with its teeth 110 is firmly butt-joined to the edge of the arbor 28 , which edge is opposite the hexagonal head receiver 62 , in such a way that the teeth 110 extend in longitudinal direction of extension of the arbor 28 . The figure further shows the way the locking element 68 , which is pre-tensioned in the direction of the gearwheel 66 , by means of a head 108 that resembles a cone, is pushed between two adjacent teeth 110 , in other words into a tooth space 111 . Each tooth 110 comprises two tooth faces 112 that meet in a tip 114 of the tooth. [0073] When the arbor 28 is rotated, the pre-tensioned locking element 68 is dislocated in that the cone 108 is pushed, by the tooth face 112 that engages the cone 108 , against the direction of force G. As soon as the cone 108 has moved over the tip 114 of the tooth the pre-tension device pushes the cone into the adjacent base 111 of the tooth and in this way fixes the gearwheel 66 , and thus the arbor 28 , in this position. [0074] FIG. 8 shows the complete fastening device 2 . It corresponds to the illustration from FIG. 3 , supplemented by the attachment plate 12 , the web 14 that is firmly connected to the attachment plate 12 , and the cylindrical eye 16 that has been formed to the web. In the web 14 there is a ring-shaped groove 116 around the eye 16 . This groove 116 ensures that the pressure member 84 of the pre-locking device 56 can project further in the direction of the left-hand limb 18 than the depth of the groove 38 in the right-hand limb 20 . Thus the overlap between the pressure member 84 of the pre-locking device 56 and the eye 16 , and thus the support area, is increased. [0075] In order to install the hatrack 4 ′ (not shown in this figure) the main bolt 26 rests in the unlocked position, thus releasing the entire width between the two limbs 18 , 20 of the fork 22 of the fork head 24 . The pre-locking device 56 is in the locking position so that the pressure member 84 projects into the fork 22 of the fork head 24 . By inserting the eye 16 in the direction of insertion E into the fork 22 , “catching” of the eye 16 takes place at first by means of the insertion aids 40 formed on the two limbs 18 , 20 . Subsequently the eye 16 is guided by the insertion aids 40 into the groove 38 . The groove 38 prevents a situation in which the eye 16 , and thus the hatrack 4 finally installed with the eye 16 , can yield laterally, across the direction of insertion E. By sliding the eye 16 further in the direction E, the eye 16 dislocates the pressure member 84 at least to near the release position in that the inclined surface 86 of the pressure member 84 slides away at the eye 16 . The pressure member 84 of the pre-locking device 56 reaches the locking position again for the first time when an opening 118 that is located in the eye 16 reaches the pressure member 84 , and the pressure member is pushed into the opening 118 due to pre-tension. The pressure member 84 of the pre-locking device 56 reaches the locking position for the second time when the eye 16 has been moved completely beyond the pressure member 84 and when the pressure member projects into the groove 116 of the web 14 . In this pre-locking position the eye 16 , or the hatrack 4 , rests on the pressure member 84 . This procedure is carried out on all the fastening devices 2 affixed to a hatrack. It may depend on the installation situation as to whether in a first installation step the eye 16 on all the fastening devices 2 is at first only inserted to such an extent that the pressure member 84 of the pre-locking device 56 moves into the opening 118 of the eyes 16 , thus securing the hatrack 4 in this position, and in a second work step the hatrack 4 is then guided on all the fastening devices 2 right to the pre-locking position, or whether the hatrack 4 on all the fastening devices 2 by means of a single installation step is moved right to the pre-locking position. After the hatrack 4 has reached the pre-locking position, the push bolt 26 , which is in the unlocked position, is moved through the opening 118 of the eye 16 , which opening 118 is now in front of the main bolt 26 , and through the transverse hole 32 of the left-hand limb 18 into its locked position. In this process the cone 78 (see FIG. 4 ) facilitates threading the main bolt 26 into the opening 118 of the eye 16 . Projection of the push button 124 into the opening 122 of the sleeve 120 ensures that the main-bolt securing device 52 pushes against the flat part 54 of the main bolt 26 , thus securing the main bolt 26 against unintended dislocation. The push button 124 also prevents rotation of the main bolt 26 relative to the fork head 24 . This installation step completes the installation procedure. The main bolt 26 , which is more strongly dimensioned when compared to the pressure member 84 , takes up the static and dynamic forces that act on the hatrack 4 during operation, and introduces said forces to the base body 30 and subsequently to the substructure 6 by way of the fork 22 of the fork head 24 . [0076] Reconfiguration of a passenger cabin or carrying out repair and maintenance work may make it necessary to deinstall the at least one hatrack 4 . [0077] In order to deinstall the hatrack 4 , first the main bolt 26 is moved from its locked position to the unlocked position. In the unlocked position the main bolt 26 completely releases the eye 16 . The eye 16 then rests on the pressure member 84 of the pre-locking device 56 that is in the locking position. By moving the pressure member 84 from the locking position to the release position, here again the eye 16 is completely released. To this effect the handle 88 (see FIG. 5 ) of the pressure member 84 is dislocated into the groove 92 of the sleeve 80 of the pre-locking device 56 , which prevents the pressure member 84 from unintentionally being pushed into the locked position by the pre-tension of the spring 90 . After this unlocking process has been completed, the eye 16 can be removed from the fork 22 of the fork head 24 . Access for dislocation of the main bolt 26 from the locked position to the unlocked position and for dislocation of the pre-locking device 56 from the locking position to the release position takes place in the same direction so that the technician does not have to change his or her working position during deinstallation on a fastening device 2 . After this deinstallation step has been carried out on all the fastening devices 2 , the hatrack 4 is no longer connected to the substructure 6 . This deinstallation step completes deinstallation of the hatrack. [0078] In addition, it should be pointed out that “comprising” does not exclude other elements or steps, and “a” or “one” does not exclude a plural number. Furthermore, it should be pointed out that characteristics or steps which have been described with reference to one of the above exemplary embodiments can also be used in combination with other characteristics or steps of other exemplary embodiments described above. Reference characters in the claims are not to be interpreted as limitations. LIST OF REFERENCE CHARACTERS [0000] 2 Fastening device 4 Hatrack 6 Substructure 8 Tie rod 10 Frame element 12 Attachment plate 14 Web 16 Eye 18 Left-hand limb 20 Right-hand limb 22 Fork 24 Fork head 26 Main bolt 28 Arbor 30 Base body 32 Transverse hole 34 Interior wall of the left-hand limb 36 Interior wall of the right-hand limb 38 Groove 40 Groove bottom 42 Groove wall 44 Edge 46 Insertion aid 48 Inclined insertion surface on the groove bottom 50 Inclined insertion surface on the groove wall 52 Main-bolt securing device 54 Flat part 56 Pre-locking device 58 Limb on the base body 60 Transverse hole 62 Hexagonal head 64 Blocking device 66 Gearwheel 68 Locking element 70 Operating knob 72 Groove 74 Projection 76 Cone 78 Highest point of the cone 80 Sleeve 82 Elongated hole 84 Pressure member 86 Inclined surface 88 Handle 90 Spring 92 Groove 94 Bush 96 External thread 98 Transverse hole 100 Clamping sleeve 102 Thread root 104 Internal thread 106 Limb 108 Head 110 Tooth 111 Tooth space 112 Tooth face 114 Tip of the tooth 116 Groove 118 Opening of the eye 120 Sleeve 122 Opening 124 Push button 126 Operating device E Direction of insertion F Direction of force G Direction of force

The invention relates to a fastening device for installing a hatrack on a substructure of a means of locomotion, wherein the fastening device comprises a pre-locking device and a main locking device. In this arrangement the pre-locking device is designed for automatic provisional affixation of the hatrack to the fastening device when the hatrack during an installation movement of the hatrack is moved in the direction to the fastening device. The main locking device is designed for final affixation of the hatrack to the fastening device.

BACKGROUND OF THE INVENTION The present invention relates generally to the field of fossil fuel cyclone-fired boilers, and in particular to the selective use of oxygen enrichment at strategic points in the barrel of a slagging cyclone combustor to maintain desired slag flow characteristics, thereby broadening the range of amenable fuels and operating conditions while lowering operating costs, improving combustion efficiency, and reducing nitrogen oxide emissions. Cyclone-fired boilers were developed in the 1940s primarily to improve the firing of coals with low ash-fusion temperature through minimizing the ash-induced slagging/fouling of high temperature heat transfer surfaces within the boiler. This was accomplished by combusting the coal and simultaneously melting the ash in a high-temperature chamber adjacent to the boiler, discharging the essentially ash-free products of combustion into the boiler and draining the molten slag to a tank at the bottom of the furnace. While this indeed reduced boiler-side fouling, the need to maintain a continuously-draining molten ash placed restrictions on the coal supply that generally increase the cost of powering the unit. Moreover, localized slag solidification within the cyclone is known to reduce unit availability while also hampering the ability to lower the firing rate and alter the stoichiometric ratio of the combustion process. (The stoichiometric ratio represents the relative proportion of oxidant to fuel used in the combustion process. A stoichiometric ratio of 1.0 is the theoretical minimum needed for complete combustion of the fuel, while a stoichiometric ratio less than 1.0 signifies fuel-rich combustion.) Finally, because of the high-temperatures needed to melt the slag, and the tendency to run at or above stoichiometric conditions, cyclone combustors are known to generate relatively high levels of nitrogen oxide (NOx) emissions, typically in the range of 1.0-2.0 lb NO 2 /MMBtu prior to post-combustion treatment. Hence, the limitations on NOx imposed by the 1990 Clean Air Act Amendments are particularly challenging and costly to achieve within fossil fuel cyclone-fired boilers. A typical cyclone combustor 10 is illustrated in FIG. 1 . Conventional combustion within a slagging cyclone combustor of this design is carried out by injecting crushed coal and primary air through a coal pipe 12 to a burner 14 . Tertiary air enters the burner at the tertiary air inlet 16 , and secondary air (the main combustion air) enters the cyclone combustor at the secondary air inlet 18 . The burner, which imparts a swirl motion to the crushed coal in the same rotation as the secondary air, injects a coal/air mixture with high tangential velocity into a refractory lined combustion chamber or barrel 20 . The coal is crushed (˜95% through 4 mesh [4.8 mm] screen) rather than pulverized (˜70-80% through 200 mesh [70 micron] screen) to minimize the escape of fines from the barrel. Coal particles are thrown outward as the flow spins through the barrel, creating a region of high heat release adjacent the refractory lining of the barrel wall. The high temperature in this region causes the ash contained within the coal to melt. The molten “slag” 22 acts as a trap for the carbon-rich coal particles, retaining the particles for a period of time far greater than the average gas residence time within the barrel, thereby enabling a high degree of carbon burnout. The molten slag eventually migrates forward along the wall of the barrel, exits at the slag spout opening 24 , and continuously drains through a slag tap opening 26 located below the re-entrant throat 28 . The gas flow makes a triple pass—initially swirling along the barrel wall toward the re-entrant throat, then swirling upstream within an annular region, and finally turning and exiting from the barrel through the re-entrant throat into the furnace 30 . Oxygen enrichment has not been used in cyclone combustors to refuel cyclone-fired boilers with coals that are not amenable to air-fuel slagging operation. However, the use of oxygen enrichment to maintain molten slag and accelerate combustion within cyclone combustors has been considered. For example, U.S. Pat. No. 2,745,732 (Oster) discloses the use of oxygen enrichment in a cyclone combustor to sustain a molten slag layer under reducing conditions in order to maximize recovery of metallic iron from the ash. The oxygen used for this purpose is introduced via a high-velocity, pre-heated, oxygen-enriched secondary air stream injected tangentially into the cyclone. U.S. Pat. No. 4,598,652 (Hepworth) discusses the possibility of using oxygen enrichment in a coal-fired cyclone combustor in which iron oxide particles are injected for sulfur capture. Although oxygen enrichment is mentioned as a possible means of accelerating the rates of reaction, there is no discussion regarding how or where the oxygen would be introduced into the cyclone combustor. Techniques for controlling ash viscosity in cyclones without the use of oxygen enrichment also have been considered. U.S. Pat. No. 5,022,329 (Rackley, et al.) and U.S. Pat. No. 5,052,312 (Rackley et al.) teach the addition of fluxing agents to maintain the T250 of the ash below 2500° F. to limit the vaporization of heavy metals. (The T250 value denotes the temperature at which a coal slag has a viscosity of 250 centipoise.) U.S. Pat. No. 6,085,674 (Ashworth) discusses the addition of lime or limestone into a cyclone to lower ash viscosity. U.S. Patent Application No. 2002/0184817 (Johnson, et al.) describes the use of an iron-based additive to modify the viscosity and slagging characteristics of coals, particularly low-sulfur Western U.S. coals. With regard to NOx reduction in cyclone combustors, U.S. Pat. No. 5,878,700 (Farzan, et al.) proposes injection of a secondary fuel (reburn fuel) along the axis of the barrel to convert NOx formed within the barrel to N 2 as gases are discharged from the unit. U.S. Pat. No. 6,085,674 (Ashworth) proposes NOx reduction through a combination of steam injection and a three-stage combustion process comprised of a fuel-rich barrel operation followed by two distinct stages of air addition. U.S. Pat. No. 6,325,002 (Ashworth) further proposes injection of tertiary and overfire air in such a way as to create in-situ recirculation of flue gases to dilute the products of combustion and further lower NOx. None of these references discloses or teaches the use of oxygen enrichment as a means to reduce NOx. Several references contemplate NOx reduction with the aid of oxygen enrichment, but without specific reference to cyclone combustors. U.S. Pat. No. 4,427,362 (Dykema) describes a combustion method requiring a high-temperature, fuel-rich first stage for the purpose of reducing NOx emissions. The high temperature (at least 1800K) is required to accelerate reaction kinetics, while fuel-rich conditions (stoichiometric ratio between 0.45-0.75) are needed to establish equilibrium chemistry with minimal NOx formation. Although this patent mentions the possibility of using oxygen enrichment, it does not provide any information on how oxygen would be introduced into the system. Moreover, this patent does not teach the use of oxygen enrichment in cyclone combustors. A similar approach to NOx reduction is discussed in U.S. Pat. No. 4,343,606 (Blair, et al.) except that this reference includes one or more secondary air injection points to complete combustion, while also omitting particulate injection. This patent teaches a first stage equivalence ratio of greater than about 1.4 (stoichiometric ratio less than about 0.7), while allowing for enrichment of air with between 6 and 15 weight percent oxygen. However, no details are provided regarding the means of introduction of the oxygen, nor is there any discussion regarding operational issues specific to cyclone combustors. U.S. Pat. No. 6,394,790 (Kobayashi) discloses a method for NOx reduction via deeply staged (i.e., exceedingly fuel-rich) oxygen-enriched primary combustion coupled with secondary oxidant injection. The oxygen concentration of the primary oxidizer is at least 30%, while the required oxidizer to fuel ratio in the primary stage is between 5% and 50% of stoichiometric. This patent teaches that high velocity injection of reactants is key to NOx reduction since the vigorous mixing it induces will serve to lower the reaction temperature. The only solid fuel explicitly mentioned in this patent is pulverized coal, suggesting that application to slagging cyclone combustors was not intended. U.S. Patent Application No. 2003/0009932 (Kobayashi, et al.) also addresses NOx reduction in coal-fired boilers via a fuel-rich first combustion stage with oxygen enrichment up to 8 volume percent. No fixed limits are placed on the first stage stoichiometric ratio, and no mention is made of ash fusibility or viscosity. Several references are made to pulverized coal (in contrast to crushed coal) and low NOx burners, suggesting that application of the method to cyclone combustors was not intended. This patent application suggests that there is a certain stoichiometric ratio (not precisely quantified) below which NOx emissions will be reduced with oxygen-enriched combustion relative to air-fuel combustion. However, the application does not contemplate the influence of aerodynamics, mixing or particle time-temperature history on NOx characteristics. A fundamental requirement for stable operation of a slagging cyclone combustor is that the ash layer remains in a molten state with sufficiently low viscosity to permit adequate drainage of the slag. Difficulties in achieving this condition contribute to reduced on-stream time and restricted load-following capability in conveniently-operated air-fuel slagging cyclone combustors. Experience has determined that the critical viscosity for adequate drainage is 250 centipoise. As previously noted, the temperature corresponding to this viscosity level is T250. Stable operation of a slagging cyclone combustor requires the temperature of the slag to be greater than or equal to T250. This requirement places limits on the allowable range of coals and operating conditions, while also contributing to higher NOx emissions than encountered in many pulverized coal combustion systems. It is desired to have a method and a system to permit refueling of cyclone combustors with coals that are not amenable to air/fuel-fired cyclone operation due to the inability to maintain a molten slag layer of sufficiently low viscosity to permit continuous slag flow. It is still further desired to have a method and a system to minimize the escape of fine coal particles from the barrel of a cyclone. It is still further desired to have a method and a system to lower NOx emissions in slagging cyclone combustors, primarily (but not exclusively) by broadening the ranges of stoichiometric ratio and firing rate, relative to air-fuel operation, under which a molten slag layer can be maintained. It is still further desired to have a method and a system to improve unit availability (i.e., on-stream time) by minimizing temperature excursions that result in freezing of the slag. It also is desired to have a method and a system for combusting a fuel in a cyclone combustor which afford better performance than the prior art, and which also overcome many of the difficulties and disadvantages of the prior art to provide better and more advantageous results. BRIEF SUMMARY OF THE INVENTION The present invention is a method and a system for combusting a fuel in a cyclone combustor. The invention also includes a method and a system for extending a range of amenable fuel types and operating parameters of a slagging cyclone combustor. In addition, the invention includes a method and a system for reducing nitrogen oxide emissions from a flue gas generated during combustion of a fuel in a cyclone combustor. Finally, the invention includes a method and a system for operating a steam-generating boiler or furnace in communication with a cyclone combustor. There are multiple steps in a first embodiment of the method for combusting a fuel in a cyclone combustor having a burner in communication with a barrel having a longitudinal axis, a burner end adjacent the burner, and a throat end opposite the burner end. The first step is to feed a stream of the fuel into the barrel of the cyclone combustor at the burner end of the cyclone combustor. The second step is to feed at least one stream of a first oxidant having a first oxygen concentration of about 21 vol. % into the barrel of the cyclone combustor at a first flowrate, the at least one stream of the first oxidant comprising at least one predominant stream of the first oxidant. The third step is to feed at least one stream of a second oxidant having a second oxygen concentration greater than the first oxygen concentration into the barrel of the cyclone combustor at a second flowrate and in a selective manner, whereby a portion of the first oxidant in the barrel of the cyclone combustor combines with at least a portion of the second oxidant in the barrel of the cyclone combustor, thereby forming a combined oxidant having a combined oxygen concentration greater than the first oxygen concentration and less than the second oxygen concentration, and at least a portion of the first oxidant from the at least one predominant stream of the first oxidant in the barrel of the cyclone combustor continues having the first oxygen concentration. The fourth step is to combust at least a portion of the fuel in the barrel of the cyclone combustor with at least a portion of the combined oxidant in the barrel of the cyclone combustor. With regard to the term “selective manner” in which the at least one stream of a second oxidant is fed into the barrel, various examples of selective feed or injection techniques are shown in FIGS. 3A-3F , 4 A- 4 B, 5 A- 5 D, and 6 A- 6 C, and are also discussed in the Detailed Description of the Invention. Persons skilled in the art will recognize, however, that there may be other techniques for feeding or injecting the at least one stream of the second oxidant into the barrel of the cyclone combustor in a “selective manner,” including but not limited to variations and modifications of the specific selective techniques illustrated and discussed herein. There are many variations of the first embodiment of the method for combusting a fuel in a cyclone combustor. In one variation, the fuel is coal. In another variation, the at least one stream of the first oxidant further comprises a primary oxidant stream having an oxygen concentration of about 21 vol. %, and at least a portion of the at least one stream of the second oxidant fed into the barrel of the cyclone combustor is combined with at least a portion of the primary oxidant stream. In yet another variation, the combined oxygen concentration is less than about 31 vol. %. In another variation of the first embodiment, at least a portion of the at least one stream of the second oxidant fed into the barrel of the cyclone combustor flows substantially along the longitudinal axis of the barrel of the cyclone combustor. In a variant of that variation, the at least a portion of the at least one stream of the second oxidant flowing substantially along the longitudinal axis of the barrel of the cyclone combustor has a swirling motion. In another variation of the first embodiment, at least a portion of the at least one stream of the second oxidant is fed into the barrel of the cyclone combustor at a location adjacent the burner end of the cyclone combustor. In yet another variation, at least a portion of the at least one stream of the second oxidant is fed into the barrel of the cyclone combustor at an intermediate location between the burner end and the throat end of the cyclone combustor. In still yet another variation, at least a portion of the at least one stream of the second oxidant is fed into the barrel of the cyclone combustor at another location adjacent the throat end of the cyclone combustor. A second embodiment of the method for combusting a fuel in a cyclone combustor is a variation of the first embodiment and includes an additional step. In the second embodiment, the at least one stream of the first oxidant further comprises a primary oxidant stream having an oxygen concentration of about 21 vol. %. The additional step is to mix at least a portion of the stream of the fuel with at least a portion of the primary oxidant stream to form a mixed stream, wherein at least a portion of the at least one stream of the second oxidant is fed into the barrel of the cyclone combustor at a location adjacent the mixed stream. Another embodiment is a method for combusting a slagging coal with at least a first oxidant having a first oxygen concentration of about 21 vol. % and a second oxidant having a second oxygen concentration greater than the first oxygen concentration in a slagging cyclone combustor in communication with a furnace while minimizing an amount of nitrogen oxide emissions in a flue gas generated during combustion of the slagging coal, the slagging coal not being amendable to use in the slagging cyclone combustor operated with a flow of air as an only oxidant, the slagging cyclone combustor having a burner in communication with a barrel having a longitudinal axis, a burner end adjacent the burner and a throat end opposite the burner end. This third embodiment includes multiple steps. The first step is to feed a stream of the slagging coal into the barrel of the slagging cyclone combustor at the burner end of the slagging cyclone combustor. The second step is to feed at least one stream of the first oxidant into the barrel of the slagging cyclone combustor at a first flowrate, the at least one stream of the first oxidant including at least one predominant stream of the first oxidant. The third step is to feed at least one stream of the second oxidant into the barrel of the slagging cyclone combustor at a second flowrate and in a selective manner, whereby a portion of the first oxidant in the barrel of the first slagging cyclone combustor combines with at least a portion of the second oxidant in the barrel of the slagging cyclone combustor, thereby forming a combined oxidant having a combined oxygen concentration greater than the first oxygen concentration and less than the second oxygen concentration, and at least a portion of the first oxidant from the at least one predominant stream of the first oxidant in the barrel of the slagging cyclone combustor continues having a first oxygen concentration. The fourth step is to combust at least a portion of the slagging coal in the barrel of the slagging cyclone combustor with at least a portion of the first oxidant and at least a portion of the combined oxidant in the barrel of the slagging cyclone combustor, thereby generating the flue gas and a stable and continuous flow of a molten slag in the barrel of the slagging cyclone combustor. The fifth step is to drain at least a portion of the stable and continuous flow of the molten slag from the barrel of the slagging cyclone combustor. The sixth step is to transfer at least a portion of the flue gas from the barrel of the slagging cyclone combustor to the furnace. There are several embodiments of the method for extending a range of amenable fuel types and operating parameters of a slagging cyclone combustor having a burner in communication with a barrel having a longitudinal axis, a burner end adjacent the burner, and a throat end opposite the burner end. The first embodiment of this method includes multiple steps. The first step is to feed a stream of the fuel into the barrel of the slagging cyclone combustor at the burner end of the slagging cyclone combustor. The second is to feed at least one stream of the first oxidant having a first oxygen concentration of about 21 vol. % into the barrel of the slagging cyclone combustor at a first flowrate, the at least one stream of the first oxidant including at least one predominant stream of the first oxidant. The third step is to feed at least one stream of the second oxidant having a second oxygen concentration greater than the first oxygen concentration into the barrel of the slagging cyclone combustor at a second flowrate and in a selective manner, whereby a portion of the first oxidant in the barrel of the slagging cyclone combustor combines with at least a portion of the second oxidant in the barrel of the slagging cyclone combustor, thereby forming a combined oxidant having a combined oxygen concentration greater than the first oxygen concentration and less than the second oxygen concentration, and at least a portion of the first oxidant from the at least one predominant stream of the first oxidant in the barrel of the slagging cyclone combustor continues having the first oxygen concentration. The fourth step is to combust at least a portion of the fuel in the barrel of the slagging cyclone combustor with at least a portion of the combined oxidant in the barrel of the slagging cyclone combustor, thereby generating a plurality of products of combustion and a stable and continuous flow of a molten slag in the barrel of the slagging cyclone combustor. A second embodiment of this method includes the additional step of draining at least a portion of the stable and continuous flow of the molten slag from the barrel of the slagging cyclone combustor. In a variation of the first and second embodiments of this method, the fuel is coal. There also are several embodiments of the method for reducing nitrogen oxide emissions from a flue gas generated during combustion of a fuel in a cyclone combustor having a burner in communication with a barrel having a longitudinal axis, a burner end adjacent the burner, and a throat end opposite the burner end. The first embodiment of this method includes multiple steps. The first step is to feed a stream of the fuel into the barrel of the cyclone combustor of the burner end of the cyclone combustor. The second step is to feed at least one stream of a first oxidant having a first oxygen concentration of about 21 vol. % into the barrel of the cyclone combustor at a first flowrate, the at least one stream of the first oxidant including at least one predominant stream of the first oxidant. The third step is to feed at least one stream of a second oxidant having a second oxygen concentration greater than the first oxygen concentration into the barrel of the cyclone combustor at a second flowrate and in a selective manner, whereby a portion of the first oxidant in the barrel of the cyclone combustor combines with at least a portion of the second oxidant in the barrel of the cyclone combustor, thereby forming a combined oxidant having a combined oxygen concentration greater than the first oxygen concentration and less than the second oxygen concentration, and at least a portion of the first oxidant from the at least one predominant stream of the first oxidant in the barrel of the cyclone combustor continues having the first oxygen concentration. The fourth step is to combust at least a portion of the fuel in the barrel of the cyclone combustor with at least a portion of the combined oxidant in the barrel of the cyclone combustor, thereby generating the flue gas containing a reduced amount of nitrogen oxide in the barrel of the cyclone combustor, the reduced amount of nitrogen oxide being less than a higher amount of nitrogen oxide that would be generated by the cyclone combustor operated with a flow of air as an only oxidant. A second embodiment of this method is similar to the first embodiment, with one variation, but includes three additional steps. The variation is that the throat end of the barrel of the cyclone combustor is in fluid communication with a furnace. The first additional step is to transfer at least a portion of the flue gas from the barrel of the cyclone combustor to the furnace. The second additional step is to feed a stream of a secondary fuel into the furnace. The third additional step is to combust at least a portion of the secondary fuel in the furnace. In a variation of the first and second embodiments of this method, the first flowrate and the second flowrate result in a stoichiometric ratio less than about 1.0 in the barrel of the cyclone combustor. There are multiple steps in the method for operating a steam-generating boiler or furnace in communication with a cyclone combustor having a burner in communication with a barrel having a longitudinal axis, a burner end adjacent the burner, and a throat end opposite the burner end. The first step is to feed a stream of the fuel into the barrel of the cyclone combustor at the burner end of the cyclone combustor. The second step is to feed at least one steam of a first oxidant having a first oxygen concentration of about 21 vol. % into the barrel of the cyclone combustor at a first flowrate, the at least one stream of the first oxidant comprising at least one predominant stream of the first oxidant. The third step is to feed at least one stream of a second oxidant having a second oxygen concentration greater than the first oxygen concentration into the barrel of the cyclone combustor at a second flowrate and in a selective manner, whereby a portion of the first oxidant in the barrel of the cyclone combustor combines with at least a portion of the second oxidant in the barrel of the cyclone combustor, thereby forming a combined oxidant having a combined oxygen concentration greater than the first oxygen concentration and less than the second oxygen concentration, and at least a portion of the first oxidant from the at least one predominant stream of the first oxidant in the barrel of the cyclone combustor continues having a first oxygen concentration. The fourth step is to combust at least a portion of the fuel in the barrel of the cyclone combustor with at least a portion of the combined oxidant in the barrel of the cyclone combustor, thereby generating an amount of thermal energy in the barrel of the cyclone combustor. The fifth step is to transfer at least a portion of the amount of the thermal energy from the barrel of the cyclone combustor to the steam-generating boiler or furnace. There are multiple elements in a first embodiment of the system for combusting a fuel in a cyclone combustor having a burner in communication with a barrel having a longitudinal axis, a burner end adjacent the burner, and a throat end opposite the burner end. The first element is a means for feeding a stream of the fuel into the barrel of the cyclone combustor at the burner end of the cyclone combustor. The second element is a means for feeding at least one stream of a first oxidant having a first oxygen concentration of about 21 vol. % into the barrel of the cyclone combustor at a first flowrate, the at least one stream of the first oxidant comprising at least one predominant stream of the first oxidant. The third element is a means for feeding at least one stream of a second oxidant having a second oxygen concentration greater than the first oxygen concentration into the barrel of the cyclone combustor at a second flowrate and in a selective manner, whereby a portion of the first oxidant in the barrel of the cyclone combustor combines with at least a portion of the second oxidant in the barrel of the cyclone combustor, thereby forming a combined oxidant having a combined oxygen concentration greater than the fist oxygen concentration and less than the second oxygen concentration, and at least a portion of the first oxidant from the at least one predominant stream of the oxidant in the barrel of the cyclone combustor continues having the first oxygen concentration. The fourth element is a means for combusting at least a portion of the fuel in the barrel of the cyclone combustor with at least a portion of the fuel in the barrel of the cyclone combustor with at least a portion of the combined oxidant in the barrel of the cyclone combustor. There are many variations of the first embodiment of the system for combusting a fuel in a cyclone combustor. In one variation, the fuel is coal. In another variation, the at least one stream of the first oxidant further comprises a primary oxidant stream having an oxygen concentration of about 21 vol. %, and at least a portion of the at least one stream of the second oxidant fed into the barrel of the cyclone combustor is combined with at least a portion of the primary oxidant stream. In yet another variation, the combined oxygen concentration is less than about 31 vol. %. In another variation, at least a portion of the at least one stream of the second oxidant fed into the barrel of the cyclone combustor flows substantially along the longitudinal axis of the barrel of the cyclone combustor. In a variant of that variation, the at least a portion of the at least one stream of the second oxidant flowing substantially along the longitudinal axis of the barrel of the cyclone combustor has a swirling motion. In another variation of the first embodiment of the system, at least a portion of the at least one stream of the second oxidant is fed into the barrel of the cyclone combustor at a location adjacent the burner end of the cyclone combustor. In yet another variation, at least a portion of the at least one stream of the second oxidant is fed into the barrel of the cyclone combustor at an intermediate location between the burner end and the throat end of the cyclone combustor. In still yet another variation, at least a portion of the at least one stream of the second oxidant is fed into the barrel of the cyclone combustor at another location adjacent the throat end of the cyclone combustor. A second embodiment of the system for combusting a fuel in a cyclone combustor is a variation of the first embodiment and includes an additional element. In the second embodiment, the at least one stream of the first oxidant further comprises a primary oxidant stream having an oxygen concentration of about 21 vol. %. The additional element is a means for mixing at least a portion of the stream of the fuel with at least a portion of the primary oxidant stream to form a mixed stream, wherein at least a portion of the at least one stream of the second oxidant is fed into the barrel of the cyclone combustor at a location adjacent the mixed stream. Another embodiment is a system for combusting a slagging coal with at least a first oxidant having a first oxygen concentration of about 21 vol. % and a second oxidant having a second oxygen concentration greater than the first oxygen concentration in a slagging cyclone combustor in communication with a furnace while minimizing an amount of nitrogen oxide emissions in a flue gas generated during combustion of the slagging coal, the slagging coal not being amenable to use in the slagging cyclone combustor operated with a flow of air as an only oxidant, the slagging cyclone combustor having a burner in communication with a barrel having a longitudinal axis, a burner end adjacent the burner and a throat end opposite the burner end. This embodiment has several elements. The first element is a means for feeding a stream of the slagging coal into the barrel of the slagging cyclone combustor at the burner end of the slagging cyclone combustor. The second element is a means for feeding at least one stream of the first oxidant into the barrel of the slagging cyclone combustor at a first flowrate, the at least one stream of the first oxidant including at least one predominant stream of the first oxidant. The third element is a means for feeding at least one stream of the first oxidant into the barrel of the slagging cyclone combustor at a second flowrate and in a selective manner, whereby a portion of the first oxidant in the barrel of the cyclone combustor combines with at least a portion of the second oxidant in the barrel of the slagging cyclone combustor, thereby forming a combined oxidant having a combined oxygen concentration greater than the first oxygen concentration and less than the second oxygen concentration, and at least a portion of the first oxidant stream from the at least one predominant stream of the first oxidant in the barrel of the slagging cyclone combustor continues having the first oxygen concentration. The fourth element is a means for combusting at least a portion of the slagging coal in the barrel of the slagging cyclone combustor with at least a portion of the first oxidant and at least a portion of the combined oxidant in the barrel of the slagging cyclone combustor, thereby generating the flue gas and a stable and continuous flow of a molten slag in the barrel of the slagging cyclone combustor. The fifth element is a means for draining at least a portion of the stable and continuous flow of the molten slag from the barrel of the slagging cyclone combustor. The sixth element is a means for transferring at least a portion of the flue gas from the barrel of the slagging cyclone combustor to the furnace. There are several embodiments of the system for extending a range of amenable fuel types and operating parameters of a slagging cyclone combustor having a burner in communication with a barrel having a longitudinal axis, a burner end adjacent the burner, and a throat end opposite the burner end. The first embodiment of this system includes multiple elements. The first element is a means for feeding a stream of the fuel into the barrel of the slagging cyclone combustor of the burner end of the slagging cyclone combustor. The second element is a means for feeding at least one stream of a first oxidant having a first oxygen concentration of about 21 vol. % into the barrel of the slagging cyclone combustor at a first flowrate, the at least one stream of the first oxidant comprising at least one predominant stream of the first oxidant. The third element is a means for feeding at least one stream of a second oxidant having a second oxygen concentration greater than the first oxygen concentration into the barrel of the slagging cyclone combustor at a second flowrate and in a selective manner, whereby a portion of the first oxidant in the barrel of the slagging cyclone combustor combines with at least a portion of the second oxidant in the barrel of the slagging cyclone combustor, thereby forming a combined oxidant having a combined oxygen concentration greater than the first oxygen concentration and less than the second oxygen concentration, and at least a portion of the first oxidant from the at least one predominant stream of the first oxidant in the barrel of the slagging cyclone combustor continues having the first oxygen concentration. The fourth element is a means for combusting at least a portion of the fuel in the barrel of the slagging cyclone combustor with at least a portion of the combined oxidant in the barrel of the slagging cyclone combustor, thereby generating a plurality of products of combustion and a stable and continuous flow of a molten slag in the barrel of the slagging cyclone combustor. The second embodiment of this system is similar to the first embodiment but includes the additional element of a means for draining at least a portion of the stable and continuous flow of the molten slag from the barrel of the slagging cyclone combustor. In a variation of the first and second embodiments of this system, the fuel is coal. There also are several embodiments and variations of the system for reducing nitrogen oxide emissions from a flue gas generated during combustion of a fuel in a cyclone combustor having a burner in communication with a barrel having a longitudinal axis, the burner end adjacent the burner, and a throat end opposite the burner end. The first embodiment of the system includes multiple elements. The first element is a means for feeding a stream of the fuel into the barrel of the cyclone combustor at the burner end of the cyclone combustor. The second element is a means for feeding at least one stream of the first oxidant having a first oxygen concentration of about 21 vol. % into the barrel of the cyclone combustor at a first flowrate, the at least one stream of the first oxidant including at least one predominant stream of the first oxidant. The third element is a means for feeding at least one stream of a second oxidant having a second oxygen concentration greater than the first oxygen concentration into the barrel of the cyclone combustor at a second flowrate and in a selective manner, whereby a portion of the first oxidant in the barrel of the cyclone combustor combines with at least a portion of the second oxidant in the barrel of the cyclone combustor, thereby forming a combined oxidant having a combined oxygen concentration greater than the first oxygen concentration and less than the second oxygen concentration, and at least a portion of the oxidant from the at least one predominant stream of the first oxidant in the barrel of the cyclone combustor continues having the first oxygen concentration. The fourth element is a means for combusting at least a portion of the fuel in the barrel of the cyclone combustor with at least a portion of the combined oxidant in the barrel of the cyclone combustor, thereby generating the flue gas containing a reduced amount of nitrogen oxide in the barrel of the cyclone combustor, the reduced amount of nitrogen oxide being less than a higher amount of nitrogen oxide that would be generated by the cyclone combustor operated with a flow of air as an only oxidant. A second embodiment of this system is similar to the first embodiment, with one variation, but includes three additional elements. The variation is that the throat end of the barrel of the cyclone combustor is in fluid communication with a furnace. The first additional element is a means for transferring at least a portion of the flue gas from the barrel of the cyclone combustor to the furnace. The second additional element is a means for feeding a stream of a secondary fuel into the furnace. The third additional element is a means for combusting at least a portion of the secondary fuel in the furnace. In a variation of the first and second embodiments of this system, the first flowrate and the second flowrate result in a stoichiometric ratio less than about 1.0 in the barrel of the cyclone combustor. There are multiple elements in the system for operating a steam-generating boiler or furnace in communication with a cyclone combustor having a burner in communication with a barrel having a longitudinal axis, a burner end adjacent the burner, and a throat end opposite the burner end. The first element is a means for feeding a stream of the fuel into the barrel of the cyclone combustor at the burner end of the cyclone combustor. The second element is a means for feeding at least one stream of a first oxidant having a first oxygen concentration of about 21 vol. % into the barrel of the cyclone combustor at a first flowrate, the at least one stream of the first oxidant including at least one predominant stream of the first oxidant. The third element is a means for feeding at least one stream of a second oxidant having a second oxygen concentration greater than the first oxygen concentration into the barrel of the cyclone combustor at a second flowrate and in a selective manner, whereby a portion of the first oxidant in the barrel of the cyclone combustor combines with at least a portion of the second oxidant in the barrel of the cyclone combustor, thereby forming a combined oxidant having a combined oxygen concentration greater than the first oxygen concentration and less than the second oxygen concentration, and at least a portion of the first oxidant from the at least one predominant stream of the first oxidant in the barrel of the cyclone combustor continues having the first oxygen concentration. The fourth element is a means for combusting at least a portion of the fuel in the barrel of the cyclone combustor with at least a portion of the combined oxidant in the barrel of the cyclone combustor, thereby generating an amount of thermal energy in the barrel of the cyclone combustor. The fifth element is a means for transferring at least a portion of the amount of the thermal energy from the barrel of the cyclone combustor to the steam-generating boiler or furnace. BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described by way of example with reference to the accompanying drawings, in which: FIG. 1 is a schematic diagram illustrating a sectional view of a typical cyclone combustor in which incoming fuel particles are thrown to the walls of the barrel by centrifugal force; FIG. 2 is a graph of adiabatic flame temperature versus oxygen enrichment for a typical fossil fuel; FIGS. 3 , 4 , and 5 are schematic diagrams illustrating a profile of a cyclone combustor, comprising a burner and a cyclone barrel having a re-entrant throat, utilizing the present invention; FIGS. 3A-3F are schematic diagrams illustrating end views ( 3 A, 3 C, 3 E) and side views ( 3 B, 3 D, 3 F) for several variations of one embodiment of the invention wherein oxygen is injected into the barrel at a location adjacent to the primary air/coal stream; FIGS. 4A and 4B are schematic diagrams illustrating an end view ( 4 A) and a side view ( 4 B) for another embodiment of the invention wherein oxygen is injected into the barrel with the primary air stream; FIGS. 5A-5D are schematic diagrams illustrating end views ( 5 A, 5 C) and side views ( 5 B, 5 D) for several variations of another embodiment of the invention wherein oxygen is injected into the barrel of the cyclone combustor along the longitudinal axis of the barrel with a swirling motion in one variation ( FIG. 5D ) and without a swirling motion in another variation (FIG. 5 B); FIG. 6A is a schematic diagram illustrating another embodiment of the invention wherein oxygen is injected into the barrel of the cyclone combustor near the burner end; FIG. 6B is a schematic diagram illustrating another embodiment of the invention wherein oxygen is injected into the mid-section of the barrel of the cyclone combustor; and FIG. 6C is a schematic diagram illustrating another embodiment of the invention wherein oxygen is injected into the barrel of the cyclone combustor near the throat end. DETAILED DESCRIPTION OF THE INVENTION The present invention is a method of combustion within a coal-fired slagging cyclone combustor with oxygen enrichment that allows for stable operation of the cyclone combustor with coals that, because of unfavorable ash fusibility/viscosity characteristics, are not amenable to conventional air-fuel slagging cyclone operation. The invention is also a method for extending the range of operating parameters of a slagging cyclone combustor (i.e., firing rate, stoichiometric ratio, coal grind size, etc.), while not adversely impacting boiler reliability or performance, by using selective oxygen enrichment to maintain a molten slag layer during conditions that would otherwise result in at least localized ash solidification. The present invention is also a system and method for reducing NOx emissions in slagging cyclone combustors. One way that NOx is reduced is through expansion of the range of stable cyclone operation (i.e., the operating range within which slag remains molten and continuously flowing), through selective oxygen enrichment, toward operating modes that produce lower NOx levels. An example of how this occurs is found in cyclone-fired boilers that utilize conventional reburn technology. In such systems, a secondary fuel, introduced downstream from the primary combustion zone (i.e., in the boiler furnace outside the cyclone barrel), converts NOx to N 2 via reaction with CH radicals. The degree of NOx reduction that can be achieved with conventional reburn technology increases as the ratio of reburn fuel to cyclone barrel fuel increases. At fixed boiler thermal load, an increase in reburn fuel can only be achieved at the expense of a reduction in cyclone barrel firing rate, a trend that, with air-fuel firing, eventually leads to lowering of the barrel temperatures and solidification of slag. Use of the present invention will lower NOx by substantially extending the attainable turn-down in barrel firing rate and, consequently, the proportion of reburn fuel utilized. A second example of NOx reduction through expansion of the stable operating range corresponds to reduction of the stoichiometric ratio within the barrel. Prior art teaches the importance of fuel-rich (i.e., sub-stoichiometric) combustion in suppressing the reactions that tend to form NOx. Fuel-rich operation in cyclones, however, dilutes the combustion reaction, thus lowering slag temperatures, eventually to the point of slag solidification. The elevated combustion temperatures generated by the present invention remove this limitation, permitting more aggressive fuel-rich operation and consequently lower NOx emissions. An alternate approach to NOx reduction embodied in the present invention is the incorporation of internal staging (i.e., staged or sequenced introduction) of oxygen within the barrel. This provides a degree of control over the mixing of coal and oxygen with cyclones not contemplated in the prior art. Hence, oxygen can, for example, be injected close to the inlet coal stream to accelerate the rate of devolatilization, or closer to the re-entrant throat, in order to facilitate final burnout of the particles. The optimal mode of internal staging, relative to NOx emissions and combustion efficiency, will depend on factors such as coal grind size, volatile fraction, firing rate and stoichiometric ratio. Prior art, which has focused on more prevalent, pulverized coal systems, does not teach or suggest such cyclone-specific methods for oxygen-enriched NOx reduction. The present invention is also a system and a method of operating a coal-fired cyclone combustor in which oxygen is strategically added at select points within the combustor in order to achieve various benefits and results. The invention is grounded in a thorough understanding of fuel and oxidant flow patterns within the cyclone barrel, chemical and physical processes occurring in the combustion of carbonaceous fuels, and techniques for coupling these pieces of information in order to efficiently utilize oxygen to attain one or more of a wide array of benefits. The selective oxygen enrichment of this invention avoids the potential pitfalls and inefficiencies of relying exclusively on oxygen enrichment techniques that premix oxygen with the predominant oxidant stream entering the combustor. The term “predominant oxidant stream” as used herein refers to the oxidant stream with the highest mass flow rate which, in the case of cyclone combustors, is generally the secondary air stream (the main combustion air) which enters the cyclone combustor at the secondary air inlet 18 shown in FIG. 1 . Premix techniques of this variety, although simple to apply, are generally less efficient since substantial dilution of the oxygen stream occurs. The relative efficiency of selective oxygen enrichment of the present invention, and premixing of oxygen in the predominant oxidant stream can, on one level, be understood by considering the respective impact on flame temperature. A graph of adiabatic flame temperature versus oxygen enrichment for a typical fossil fuel is shown in FIG. 2 . With premixing of oxygen and air, the average enrichment level of the oxidant stream limits the increase in flame temperature. For example, with five percent pre-mixed enrichment, a maximum increase in adiabatic flame temperature (above air-fuel combustion) of 400-500° F. can be achieved. By contrast, strategic injection of an essentially pure oxygen stream with coal is capable of elevating the flame temperature locally by as much as 1500° F. As radiation heat transfer is proportional to absolute temperature to the fourth power, it is clear that the radiant heat delivered to the slag layer has the potential to be far greater with selective oxygen enrichment such as that of the present invention. Moreover, as combustion kinetics are exponentially related to flame temperature, more complete carbon burnout can be achieved with the present invention. Further, as premixing of the predominant oxidant stream has a global effect within the cyclone barrel, rather than a local effect as produced by the selective oxygen enrichment of the present invention, a degree of control in the mixing processes between fuel and oxidant is lost. Hence, when enrichment is carried out by premixing oxygen with the predominant oxidant stream (as contrasted with selective oxygen enrichment of the present invention), it is much more difficult to precisely isolate phenomena and attain desired results without inadvertently producing undesired or unintended side-effects. Although the specific methods of oxygen enrichment will vary with factors such as cyclone/boiler design, load profile, coal characteristics, and the particular benefits sought, the following techniques are among those within the scope of the present invention. Primary air is often (but not always) used as the transport medium for the crushed coal introduced into the cyclone and typically represents about 10-20% of the stoichiometric air required for complete combustion. In such designs, the primary air/coal stream enters the cyclone with a tangential orientation with respect to the barrel. FIGS. 3 and 3 A- 3 F show three variations of an embodiment of the present invention wherein oxygen is injected into the barrel 20 via the burner 14 with the primary air/coal stream. Tertiary air is injected into the tertiary air inlet 16 and enters the burner 14 through an orifice 15 in all three variations. In the variation shown in FIGS. 3A and 3B , a stream of oxygen is injected side-by-side with the primary air/coal stream into the burner via conduit 13 . In the second variation illustrated in FIGS. 3C and 3D , a stream of oxygen is injected above the primary air/coal stream. In the third variation shown in FIGS. 3E and 3F , a stream of oxygen is injected below the primary air/coal stream. In all three variations, the oxygen stream is injected adjacent to the primary air/coal stream and with a similarly oriented swirling motion as that of the primary air/coal stream. FIGS. 4 and 4 A- 4 B show another embodiment of the invention in a system wherein primary air and coal enter the burner 14 separately through conduit 13 and coal pipe 12 . In this embodiment, a stream of oxygen is added directly to the primary air stream, and both streams enter the burner through conduit 13 . The oxygen enrichment techniques shown in FIGS. 3A-3F and FIGS. 4A-4B provide intimate, essentially undiluted contact between the coal and oxygen with little or no disturbance to existing cyclone flow patterns. This mode of oxygen enrichment will therefore generate high temperatures, providing enhanced radiation heat transfer to the slag and initiating rapid devolatilization of coal in the early stages of combustion. Rapid devolatilization, when coupled with locally fuel-rich conditions, is an established means for lowering NOx emissions in coal-fired systems. In another embodiment, oxygen is injected along the axis of the barrel 20 toward the re-entrant throat 28 , as shown in FIGS. 5A-5D . This provides a source of improved burnout for fine coal particles that would otherwise exit the barrel un-reacted, for example as is prone to occur with low viscosity slag produced by some coals, especially some Western U.S. coals. The combustion of fines will, in turn, augment the rate of radiant heat to the slag layer. Axial injection of oxygen, without swirl and with swirl, is shown in FIGS. 5B and 5D . In the embodiment shown in FIGS. 5A and 5B , coal is injected through the coal pipe 12 , primary air is injected through conduit 13 , tertiary air is injected through tertiary air inlet 16 , and oxygen is injected into the burner 14 through a lance 17 . Alternatively, the oxygen may be pre-mixed with the tertiary air and injected together with the tertiary air at the tertiary air inlet 16 . In the embodiment shown in FIGS. 5C and 5D , a swirling motion is imparted to the axial injection of oxygen that is of the same orientation as the primary air or primary air/coal stream. The swirling action diffuses the oxygen outward toward the larger coal particles. The swirl number (ratio of tangential to axial momentum) of the centerline oxygen flow can be varied to control the rate of jet expansion and, hence, the predominant region of the barrel in which mixing of oxygen and coal occurs. In the embodiments shown in FIGS. 6A-6C , oxygen is introduced at various points downstream from the primary air/coal injection point, either within or adjacent to the secondary air stream, and typically following the same swirl orientation as the secondary air. This method of enrichment provides an additional level of mixing control between the oxygen and the coal. That is, varying the position of oxygen enrichment along the barrel length assists in determining the time-temperature-O 2 concentration history of the individual coal particles as they traverse the barrel. This degree of control, if properly leveraged, can be used to reduce NOx emissions, locally augment radiant heat transfer, and enhance carbon particle burnout, while maintaining the slag layer in a molten and continuously flowing state. In the embodiment shown in FIG. 6A , a stream of oxygen 36 is injected into a lance 17 inserted in the secondary air inlet 18 at a point near the burner end 32 of the cyclone barrel 20 , which has a burner 14 at the burner end 32 of the cyclone barrel. The oxygen flows into the barrel together with the secondary air flow 38 . In FIG. 6B , the stream of oxygen 36 is injected through the lance 17 inserted through the secondary air inlet 18 at a location approximately in the middle of the barrel 20 . The oxygen flows into the barrel together with the secondary air flow 38 . In FIG. 6C , the stream of oxygen 36 is injected in lance 17 inserted in the secondary air inlet 18 at a location near the throat end 34 of the cyclone barrel 20 . The oxygen flows into the barrel together with the secondary air flow 38 . Persons skilled in the art will recognize that the lance 17 illustrated in FIGS. 6A , 6 B, and 6 C may be replaced by any means that will facilitate selective oxygen enrichment in localized regions of the cyclone barrel. While specific embodiments of the present invention have been described in detail, persons skilled in the art will appreciate that various modifications and alterations may be developed in light of the overall teachings of the disclosure. For example, the invention may be used with many types of carbonaceous fuels, including but not limited to: anthracite, bituminous, sub-bituminous, and lignitic coals; tar and emulsions thereof; bitumen and emulsions thereof; petroleum coke; petroleum oils and emulsions thereof; water and/or oil slurries of coal; paper mill sludge solids and sewage sludge solids; and combinations and mixtures of all of those fuels. Accordingly, although illustrated and described herein with reference to certain specific embodiments and variations thereof, the present invention is nevertheless not intended to be limited to the details shown and described. Rather, various modifications may be made in the details within the scope and range of equivalents of the claims and without departing from the spirit of the invention.

A method for combusting a fuel in a cyclone combustor having a burner and a barrel includes: feeding a stream of the fuel into the barrel at the burner end of the barrel; feeding a stream(s) of a first oxidant (e.g., air) having a first oxygen concentration into the barrel at a first flowrate, the stream(s) of the first oxidant including a predominant stream; feeding a stream(s) of a second oxidant (e.g., oxygen) having a second oxygen concentration into the barrel at a second flowrate and in a selective manner, whereby a portion of the first oxidant combines with a portion of the second oxidant, thereby forming a combined oxidant having a combined oxygen concentration, and a portion of the first oxidant from the predominant stream continues having the first oxygen concentration; and combusting a portion of the fuel with a portion of the combined oxidant in the barrel.

FIELD OF INVENTION [0001] The invention relates to a method for making a self-contained renewable power source comprising a power generation unit harnessing external motion and exploiting the corresponding mechanical energy to generate electrical energy, an energy management unit that rectifies the generated AC electrical energy and manages its storage and utilization, and a specialized energy storing element which stores the energy and delivers it subsequently, upon demand. [0002] Components comprising the micro-generator unit are contained within a preferably hermetically sealed enclosure attached, anchored or secured to a moving body that imparts the motion to the enclosure and consequently to the motion harnessing element and the contained piezoelectric element. The enclosure containing the piezoelectric element and the motion harnessing element, constituting a part of the invented device, is set in motion by implanting and affixing the invented device to a moving body like a heart, or other in-body moving organs, or more generally attaching the device on the interior or exterior of a moving mammal or vehicle or other moving or vibrating object providing activation to the harnessing element. [0003] The activation is applied to a cantilever, or strip, bending-type piezoelectric element or any other shape susceptible to bending and/or flexing thereby causing displacement and/or deformation of the element and resulting in the generation of electrical energy. In particular, the invention discloses specific constructions of the piezoelectric element that optimizes it's efficiency as a generator under conditions of low and variable activation force, limited space, for general use and for an implantable device in particular that operates preferably at almost constant and relatively low temperatures, and at low and variable frequency. The invention relates to special designs leading to decreased structural stiffness and increased piezoelectric capacitance. Minimizing the stiffness is of primary importance since it enables lowering of resonance frequency, decreases mechanical damping and enables use of minimal activation force. Both the reduced stiffness and the increased capacitance result in extensive gains in conversion efficiency of the mechanical to electrical energy of the piezoelectric element(s) and increases the overall energy output, while rendering the operation at low frequencies, in the range of a few cycles per second to a few seconds per cycle, more effective. [0004] The inventions relates also to the design of the piezoelectric holding fixture enabling three-dimensional (3-D) activation of the piezoelectric bending element, regardless the orientation of the enclosure relative to the gravitation forces. [0005] The current invention further discloses a method enabling efficient transfer of the electrical energy generated through flexing of the piezoelectric element(s), to the energy storage unit using an energy management unit that rectifies the generated AC electrical energy and manages its storage and utilization, and a specialized energy storing element which stores the energy and delivers it subsequently, upon demand. BACKGROUND OF INVENTION [0006] Modern medical science employs numerous electrically powered devices which are implanted in a living body. For example, such devices may be employed to deliver medications, to support blood circulation as in a cardiac pacemaker or artificial heart, a drug pump and the like. Most implantable devices contain primary batteries which have a limited lifetime, contain active chemicals imposing stringent sealing techniques and occupy substantial volume and weight. In some cases rechargeable batteries are used and recharged by transcutaneous induction of electromagnetic fields in implanted coils connected to the batteries or by ultrasonic means. Transcutaneous inductive recharging of batteries in implanted devices is disclosed for example in U.S. Pat. Nos. 3,923,060; 4,082,097; 4,143,661; 4,665,896; 5,279,292; 5,314,453; 5,372,605, and many others. [0007] Due to practical limitation of batteries, a number of implanted devices powered without batteries have been proposed. A variety of techniques based on mechanical and hydraulic principles to harness the physical motion of a heart or other in-body moving organs, to generate electrical energy for pacing, or other electronic implants are disclosed: U.S. Pat. No. 3,486,506, December 1969, and U.S. Pat. No. 3,554,199, January 1971 disclose a cardiac pacemaker that includes a balance wheel driven by heart motion. The balance wheel is coupled to a magnet rotor to induce electric pulses in a stator coil. U.S. Pat. No. 3,563,245, February 1971 discloses a pressure actuated electrical energy generating unit. A pressurized gas containing bulb is inserted into the heart whereby the contractions of the heart exert pressure on the bulb and cause the pressure within the bulb to operate bellows remotely positioned with respect to the heart. The bellows in turn operate an electrical-mechanical transducer. U.S. Pat. No. 3,693,625, September 1972 discloses a device for supplying electrical energy to a heart stimulator placed within the human body in close proximity to the heart muscle. The generator contains a rotor coupled to magnet and induction coil, the rotor being driven by fluid contained within two elastic bags periodically contracted through heart motion thereby pushing the liquid from bag to bag via piston chambers that drive the rotor. U.S. Pat. No. 3,826,265, July 1974 discloses mechanical pulse generator for cardiac pacing. The generator is composed of a harnessing mechanism containing bladder, fluid, bellows or spring to transfer the motion to a torsion spring coupled to a shaft and induction coil. U.S. Pat. No. 3,906,960, September 1975 discloses energy converter integrated into a pacemaker electrode implantable in a vessel or heart ventricle or in muscle, with gas filled and sealed housing. Electricity generation is based on activation of a bi-stable magnet spring system, integrated with a reluctance generator and an energy storage element. U.S. Pat. No. 5,810,015, September 1998 discloses a power supply for implantable devices, activated by mechanical, chemical, thermal, or nuclear energy into electrical energy. The invention provides a method of supplying energy to an electrical device within a mammalian body in which the mammal is implanted with an apparatus including a power supply capable of converting non-electrical energy into electrical energy and the non-electrical energy is transcutaneously applied to the apparatus. [0008] The utilization of piezoelectric materials as actuators and sensors is increasing. Miniaturized power sources for MEMS and microelectronics are in growing demand. Combining the needs for Miniaturization with the extremely low-power consumption of the newly emerging microelectronic technologies leads to increased interest in piezoelectric materials as micro-generators. The use of piezoelectric materials yields significant advantages for micro-power systems. The energy density achievable with piezoelectric devices is potentially greater than that possible with electrostatic of electromagnetic designs. Also, the fact that piezoelectric elements are not affected by external magnetic fields is specifically important feature in the case of implantable devices. Since piezoelectric elements convert mechanical energy into electrical energy via strain, or stress, with displacements in the range of microns, they have an inherent advantage in miniaturization. The absence of active chemicals like those contained in batteries, eliminates the need for specific sealing means, and eliminates the limit on life-time. Piezoelectric benders have proven themselves reliable for 10 9 cycles and more. [0009] Harnessing mechanical motion to activate piezoelectric element thereby producing electrical energy has been disclosed in variety of patents: U.S. Pat. No. 5,751,091, May 1998, discloses a piezoelectric power generator for a portable power supply and portable electronic applications. U.S. Pat. No. 5,835,996, November 1998 discloses a power generator using a piezoelectric element with specific parameters of the activation displacement providing high efficiency of power generation. The patent points out the function of the ratio of the initial unloaded voltage value of the piezoelectric to a prescribed output voltage of the piezoelectric. The practically preferred ratio of the piezoelectric Open Circuit Voltage to Load Voltage is claimed to be in a quite wide range of approximately two to twenty. US Patent Application 20040212280, October 2004 discloses a force-activated electrical power generator using piezoelectric elements with specific rectification, filtering and other conditioning components. US Patent Application 20050082949, April, 2005 discloses a stacked multilayer piezoelectric element attached to a mechanical device providing deformation of the piezoelectric element. US Patent Application 20050225207, October 2005 refers to a belt piezoelectric generator generating continuous alternate current by mechanically moving a multi-electrode piezoelectric endless ceramic belt between two rows of rollers so that the belt forms a wavy shape Piezoelectric. US Patent Application 20050280334, December 2005 discloses a piezoelectric power generator comprising plural piezoelectric devices arranged in circular patterns and activated by a rotating actuator. The resultant AC voltage is rectified and utilized to charge battery or capacitor. US Patent Application 20050288716, December 2005 discloses a piezoelectric acupuncture device, applied externally to chest of a patient whose heart is in cardiac arrest for restoring normal contraction rhythms of a heart, or for pacing a heart. The piezoelectric activation is conducted manually. US Patent Application 20050269907, December 2005 refers to a power generator employing piezoelectric materials. [0010] As shown above, the use of piezoelectric elements in implantable devices as sensors or power generators has been disclosed in several publications and patents. In general three basic principles of piezoelectric deformation-activation are disclosed: (a) Kinetic activation where the piezoelectric element is affixed to the moving organ, like the heart, in such a manner that it is flexed through heart contraction and expansion; (b) inertial activation where a ballast weight is attached to the piezoelectric element and (c) Transcutaneous activation, through applying ultrasonic energy by an external transmitter to set the piezoelectric element in motion such that it may be used as a sensor, actuator or a micro-generator. [0011] Utilization of piezoelectric material in the form of foils or bands wrapped around a patient's chest or leg for measuring heart beats and blood flow has been suggested by E. Hausler et all in IEEE 1980 Biomedical Group Annual Conference, Frontiers of Engineering in Health Care, and by Michael A. Marcus in Ferroelectrics, 40 1982, “Ferroelectric Polymers and their Application”. In 1984 Haustler et all proposed a power supply based on PVDF (polyvinylidene fluoride) piezoelectric that could be surgically implanted in an animal to convert mechanical work done by a dogs' breathing into electrical energy, Ferroelectronics, 60, 277, “Implantable physiological power supply with PVDF film”. [0012] U.S. Pat. No. 3,456,134, July 1969 discloses an encapsulated cantilevered beam composed of a piezoelectric crystal mounted in a metal, glass or plastic container and arranged such that the cantilevered beam will swing in response to movement. The cantilevered beam is further designed to resonate at a suitable frequency and thereby generate electrical voltage. U.S. Pat. No. 3,659,615, May 1972 discloses a piezoelectric bimorph encapsulated and implanted adjacent to the left ventricle of the heart and arranged to flex in reaction to muscular movement to generate electrical power. U.S. Pat. No. 4,140,132, February 1979 discloses a cantilever piezoelectric crystal mounted within an artificial pacemaker can having a weight on one end, and constructed to vibrate to generate pulses which are a function of physical activity. U.S. Pat. No. 4,690,143, September 1987 claims a pacing lead with a piezoelectric device included in a catheter distal end portion with a piezoelectric device and is adapted to be inserted into a human heart. The piezoelectric device is designed to generate electrical energy in response to movement of the implanted pacing lead upon contraction of the heart. The device can be made of a ceramic bimorph or a PVDF film. U.S. Pat. No. 5,431,694, July 1995 discloses a piezoelectric generator in the form of a flexible sheet of poled PDVF which while being bent generates an electrical current to charge the storage device. The generator is adaptable to be attached to a structure which can repetitively bend it, and to generate an electrical current while being bent. The bending action is provided by the heart muscle, by lung expansion or bending of a rib, as examples. The storage device is adapted to be connected to a user device such as a pacemaker. U.S. Pat. No. 6,654,638, November 2003 discloses an implantable, ultrasonically activated piezoelectric element receiving the mechanical energy for activation from a source external to the implantable electrode. US Patent Application 20050027323; February 2005 discloses an implantable medical device utilizing a piezoelectric crystal for monitoring signs of acute or chronic cardiac heart failure by measuring cardiac blood pressure and mechanical dimensions of the heart and providing multi-chamber pacing. The sensor comprise at least two sono-micrometer piezoelectric crystals, one serving an ultrasound transmitter when a drive signal is applied to it and the second, attached to a second lead body implanted into or in relation to a second heart chamber that operates as an ultrasound receiver. US Patent Application 20050052097, March 2005 claims for a piezoelectric power generation system which performs a highly efficient power generation using a piezoelectric element without dependency on the direction of an externally driven vibration. The system includes a vibrator having a cantilever beam in the form of a rod and an impact element such as a steel ball. The dependency on the vibration direction in the vibrator is minimized to improve the efficiency of power generation. SUMMARY OF THE INVENTION [0013] The disclosed piezoelectric micro-generator is intended to generate maximal electrical energy with minimal activation force, at low frequency and small size of the piezoelectric element and to provide most effective architecture with respect to size and transformation efficiency. [0014] The disclosed micro-generator is adapted to pick up external motion and convert the aforesaid motion into electrical impulses by means of an oscillating piezoelectric element. The aforesaid piezoelectric element is provided with a mechanical harnessing unit inertially affecting the piezoelectric element. It should be appreciated that the harnessing unit is exposed to an externally applied force caused by the patient's body or a specific organ and gravitation force. Efficiency of the piezoelectric conversion of mechanical energy can be performed due to orienting the piezoelectric element optimally to the applied forces. In accordance with one embodiment of the current invention, the proposed device comprises a gyro system adapted to optimally orient the piezoelectric element. [0015] The micro-generator further comprises a power control unit which manages providing electrical energy generated by the piezoelectric element to the energy storage unit. The power control unit is adapted to decouple the piezoelectric element from the energy storage unit and to ensure energy transformation according to present conditions ensuring optimal trade-off. [0016] It is hence one object of the invention to disclose a power supply for implanting into a patient's body and providing electricity to a load within the body. The aforesaid power supply comprises an enclosure which is adapted for optimizing an activating force by means of orienting thereof; the power supply further comprises (a) a piezoelectric micro-generator comprising (i) a piezoelectric element/having an elongate shape with first and second terminals; said first terminal mechanically connected to said enclosure; said piezoelectric element configured for substantially resonant oscillation at frequency characterizing motion of said patient's heart or other organ; (ii) a mechanical harnessing unit mechanically connected to said second terminal of said piezoelectric element to increase an oscillation amplitude of said piezoelectric element; (b) electrical energy storing means; (c) control unit adapted for managing charging and discharging said storing means [0022] The control unit is further provided with means for decoupling the piezoelectric element from and connecting to the electrical energy storing means to increase efficiency of the power supply. [0023] Heart, limb and any other moving parts and organs of patient's are in the scope of the current invention. [0024] When the proposed device is attached to the cardiac muscle, contractions thereof cause device displacement. The mechanical harnessing unit inertially affects the piezoelectric element, specifically, that causes oscillation of the piezoelectric element. [0025] Another object of the invention is to disclose the piezoelectric element configured as a laterally bending cantilever.?? [0026] A further object of the invention is to disclose the generator comprising a power control unit adapted to effectively convert electrical oscillations of ultralow frequency created in the piezoelectric element between activation events. [0027] A further object of the invention is to disclose the power control unit adapted to accumulate energy of activation impulses independently of repetition rate thereof. variations in ?? [0028] A further object of the invention is to disclose the power control unit adapted to compensate differences between condition of physical activity and rest. [0029] A further object of the invention is to disclose the power control unit adapted to perform at least one function selected from the group consisting of voltage rectification, the storage unit, providing stored electricity to the load and any combination thereof. Decoupling? Controlling? Switching> [0030] A further object of the invention is to disclose the electrical energy storage comprising an array of storing elements. [0031] A further object of the invention is to disclose the electrical energy storage comprising at least one capacitor. [0032] A further object of the invention is to disclose the electrical energy storage comprising at least one rechargeable battery. [0033] A further object of the invention is to disclose the piezoelectric element configured for substantially resonant oscillation with a frequency ranged between about 1 and 3 Hz. [0034] A further object of the invention is to disclose the piezoelectric element which is made of PZT ceramics. [0035] A further object of the invention is to disclose the piezoelectric element configured as a multilayer structure (a piezoelectric stack). [0036] A further object of the invention is to disclose the piezoelectric stack comprising at least one inactive layer adapted to strengthen the stack while minimally impeding the optimize elasticity thereof. [0037] A further object of the invention is to disclose the piezoelectric element disposed in a holder which is adapted for linear displacement along an axis of the piezoelectric element, angular displacements around the axis of the piezoelectric element and in a plane of the piezoelectric element to orient the piezoelectric element perpendicularly to the activating force. [0038] A further object of the invention is to disclose a method of piezoelectric conversion of a patient's body motion into electrical energy. The aforethe method comprising the steps of: (a) providing a micro-generator further comprising (i) a enclosure; (ii) a piezoelectric element having an elongate shape with first and second terminals; the first terminal mechanically connected to the enclosure; the piezoelectric element configured for substantially resonant oscillation at frequency characterizing motion of the patient's body; and (iii) an electric energy storing means; (b) implanting into the patient's body; and (c) inertially picking up mechanical energy of body motion.?? [0039] It is a core purpose of the invention to provide the step of picking up mechanical energy performed by the piezoelectric element provided at the second terminal with a mechanical harnessing unit to increase oscillation amplitude of the piezoelectric element.??? [0040] A further object of the invention is to disclose the method further comprising a step of effectively converting electrical oscillations of ultralow frequency created in the piezoelectric element between activation events. [0041] A further object of the invention is to disclose the method further comprising a step of compensating the beat to beat variation in frequency and activation force. [0042] A further object of the invention is to disclose the method further comprising a step of accumulate energy of activation impulses independently of variations in ??repetition rate thereof. [0043] A further object of the invention is to disclose the method further comprising a step of performing at least one function selected from the group consisting of voltage rectification, charging the storage unit, providing stored electricity to the load and any combination thereof. See above [0044] A further object of the invention is to disclose the method further comprising a step of linearly displacing the piezoelectric element along an axis thereof, angularly displacing of around the axis of the piezoelectric element and in a plane of the piezoelectric element to orient the piezoelectric element perpendicularly to an activating force. BRIEF DESCRIPTION OF THE DRAWINGS [0045] In order to understand the invention and to see how it may be implemented in practice, a plurality of embodiments is adapted to now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which [0046] FIGS. 1 a and 1 b are schematic views of coin and prismatic embodiments of the piezoelectric generator, respectively; [0047] FIGS. 2 a and 2 a are schematic views of the unimorphic cantilever bender in balanced and loaded positions; [0048] FIG. 3 is an electric diagram of the bimorph cantilever bender; [0049] FIG. 4 is an electric diagram of the monoblock cantilever bender; [0050] FIGS. 5 a and 5 b are electric diagrams of the parallel and series cantilever generator, respectively; [0051] FIGS. 6 and 7 are temperature dependences of the ratio and compound of piezoelectric voltage and strain constants d 31 and g 31 , respectively; [0052] FIGS. 8 a - 8 e are schematic diagrams of angular and linear motions of the piezoelectric element, [0053] FIG. 9 a is a time curve of the cardiac acceleration; [0054] FIG. 9 b is a time curve of the piezoelectrically generated voltage; [0055] FIG. 10 a is a geometric scheme of the micro-generator orientation relative to the heart; and [0056] FIG. 10 b is a graph of the generated voltage in dependence on the geometric orientation. DETAILED DESCRIPTION OF THE INVENTION [0057] The following description is provided, alongside all chapters of the present invention, so as to enable any person skilled in the art to make use of said invention and sets forth the best modes contemplated by the inventor of carrying out this invention. Various modifications, however, are adapted to remain apparent to those skilled in the art, since the generic principles of the present invention have been defined specifically to provide a piezoelectric micro-generator. [0058] The components comprising the piezoelectric micro-generator device include: (a) Enclosure—can anchored to the moving body and including the parts comprising the micro-generator. (b) Harnessing mechanism—mechanism trapping and transforming the motion of the enclosure to impart deflection/deformation to the piezoelectric element; (c) piezoelectric element—element converting the mechanical motion of displacement/distortion to electrical energy; (d) charging power management—unit rectifying the AC output of the piezoelectric to DC voltage and controlling the transmission of the electrical energy generated by the piezoelectric element to the energy storage unit; (e) energy storage—unit charged by the piezoelectric, through the charging power management unit; (f) delivery power management—unit controlling the delivered energy from the energy storage unit to the external load. In practical terms, the charging power management and the delivery power management may be designed as a single IC unit maintaining both functions; (g) Electrodes—electrodes associated with the enclosure can and providing the output energy from the energy storage unit to the external load. [0059] As described above, conversion of the exterior motion to electrical energy stored by the energy storage unit takes place via several steps, each step being associated with corresponding efficiency. (1) Harnessing efficiency—defining the extent the harnessing mechanism succeeds to trap the exterior motion and convey it to the piezoelectric element; (2) Conversion efficiency—defining the extent to which the mechanical energy applied on the piezoelectric element and causing its' deformation is converted to electrical energy generated by the piezoelectric element at open circuit conditions; (3) Transformation efficiency—defining the extent to which the electrical energy generated at the piezoelectric element is transformed to the energy storage unit. [0060] The total efficiency of converting mechanical motion to electrical energy stored at the energy storage unit (battery or capacitor) is the multiplication of all three efficiencies [0000] η t =η 1 *η 2 *η 3 . [0061] In practical applications, limitations of size, activation force and frequency are imparted. To achieve maximal total efficiency imposed by practical conditions, trade-off optimization is unavoidable. [0062] The conversion efficiency of mechanical to electrical energy is a fundamental parameter for the development and optimization of a power generation device and it has been discussed in many publications. All have noted that high efficiency for piezoelectric conversion requires large quality (Q) and electromechanical coupling (k 2 ) factors. However, no work has been conducted to provide optimal conditions upon utilization of miniature piezoelectric elements of less than 50 cubic millimeters, should be activated by minimal force in the range of a few milli-Newton and at low frequency of less than 3 Hz under variable frequency, activation force and motion. It should be noted as well that the maximal conversion efficiency discussed in literature and related to the Q and k 2 factors is related to piezoelectric at Open Circuit Voltage (OCV) conditions while at practical application the generated energy at OCV has to be utilized to charge the energy storage unit. Furthermore, practically all previous designs have been targeted to perform under stable conditions and at the resonance frequency. However, the present invention addresses conditions typical of biological systems, where the frequency is variable and the activation force and the details of the motion vary from cycle to cycle. Hence, the current invention provides design solutions to the challenge of working at a broader frequency band and under unpredictably variable conditions. [0063] At the other interface of the piezoelectric element, there are also publications discussing the optimal conditions ensuring maximal efficiency to deliver the generated electrical energy from the piezoelectric element to the energy storage unit. However, also here there is no discussion how the outlined optimal parameters should be matched with miniature size of piezoelectric element that are activated by minimal force and operated at low frequency. [0064] This application discloses the design of a piezoelectric element intended to generate maximal electrical energy at OCV with minimal activation force, at low frequency and small size of the piezoelectric element, and an energy storage unit that is specifically designed to match the piezoelectric element of prior application and is designed to fit the special operation and size conditions described above and to provide most effective architecture with respect to size and transformation efficiency. [0065] Reference is now made to FIGS. 1 a and 1 b, presenting a micro-generator 100 of coin and prismatic shapes, respectively, which comprises a housing 10 and a piezoelectric element 20 . The piezoelectric element 20 , of a cantilever or other shape but still a strip-bending type, held by a holder 30 , is activated by a mechanical harnessing unit 40 that is permanently fixed to the piezoelectric activation tip. The piezoelectric element comprises of a mono-block cantilever, each block constructed of a multi-layer stack, each stack containing at least five electrically parallel connected layers, each layer typically 15-20 micron thick. As shall be discussed elsewhere, the thin layers, the parallel connection of the stacked layers and the mono-block piezoelectric design allows the achievement of high piezoelectric capacitance and very low stiffness, enabling piezoelectric displacement-activation by a very small force and piezoelectric vibration flexing at resonance, or close to resonance frequency are critical parameters for achieving maximal power output at minimal activation force and low vibration frequency. [0066] The power control unit takes part in transformation of the generated electrical energy by the piezoelectric to the energy storage unit. The function of this unit is to decouple the piezoelectric element from the energy storage unit and to ensure energy transformation according to present conditions ensuring optimal trade-off. It is a further function of the power control unit to create an ongoing adaptation of the charging link between the piezoelectric element and the appropriate capacitor(s) as the charging conditions change at several levels: 1) the damping in the amplitude of individual self-vibrations of the piezoelectric element that occur between activation events 2) the beat to beat variation in frequency and activation force; 3) the differences between condition of physical activity and rest. The power control unit maintains the functions of voltage rectification, control and switching and it is operated at ultra low power consumption. It is the scope of the current invention to disclose energy storage unit comprised of several independent capacitors switched/coupled to the piezoelectric element in specified sequence by the power management unit. Prevention of permanent parallel contact of the energy storage capacitor to the piezoelectric element ensures high transformation efficiency upon conveying the electrical energy from the piezoelectric element to the energy storage elements. [0067] According to one design of the invention, the same power management unit may serve also to control and switch the output power per output parameters of the algorithm element comprising the power delivery. As to be discussed elsewhere, the efficiency of removing the electrical energy from the piezoelectric element to charge an energy storage element is strongly affected by the relative values of the OCV generated by the piezoelectric deformation and the voltage of the energy storage element that is charged by the piezoelectric through the power control unit. The current invention discloses the proper design parameters to mach the piezoelectric OCV and the voltage of the energy storage element as to ensure utilization of the piezoelectric electrical energy at high efficiency. [0068] The energy storage unit is comprised of several, but at least two, capacitors, each being independently charged by the power control unit. As to be discussed elsewhere, utilization of capacitors provides an inherent advantage over use of rechargeable battery. The type of capacitor and the capacitance value are also key parameters markedly determining the micro-generator performance and shall be discussed in details. [0069] The power delivery unit comprises an algorithm element and it is coupled to the external load by electrodes which extend from the case or comprise an integral part of it. The electrodes provide the electrical connection to the heart. According to one design of the invention, the electrodes also function as attachment of the case to the heart, in such a way that does not restrict their use as voltage terminals to deliver the output power for any external load. In the case of heart pacing, the algorithm element receives the input (sensing) voltage trough the electrodes and determines whether a pulse will be delivered, and creates the appropriate architecture of the capacitor array to deliver the required output voltage amplitude and the width of the delivered pulse. A separate output power control, or single input/output control and switching elements may be used to control and switch the charging and discharging modes of the capacitors. According to the current invention no DC-to-DC converter is necessary to deliver output voltages at variable values, as determined by the algorithmic element. It is the function of the output switching power controller to interconnect the capacitors in single, series, or parallel architectures as to maintain the output voltage levels and stable voltage output at any voltage and pulse width. More details shall be disclosed elsewhere. [0070] Accordingly, it is the scope of the present invention to provide a functionally optimal method of power generation and energy storage, comprising a self-contained micro-generator having a high efficiency of harnessing exterior motion by affixing the micro-generator to a moving body and including a special piezoelectric cantilever to generate electrical energy, and a means of efficient energy storage adapted to the self-contained power generation method and power generator. [0071] Since the external motion may occur in any direction in space, and these directions may vary in relation to the force of gravity, it's the further scope of the invention to describe a special device for holding and orienting the piezoelectric element that is capable of harnessing the external motion regardless the direction of its component vectors in space. [0072] A further objective is to provide coupling of the special design of the piezoelectric element with a special energy storage unit explicitly coupled to the piezoelectric element such as to achieve efficient utilization of the generated energy. [0073] It is an object of the present invention to provide a small size, high performance power generator and energy storage unit. Still other objectives and advantages of the invention will in part be obvious from the detailed specifications to follow. This invention accordingly comprises the several construction and design elements and the relation of one or more of which with respect to each of the others and the apparatus embodying features of construction, combinations of elements and arrangement of parts which are adapted to effect such performance, all as exemplified in the following detailed disclosure and the scope of the invention will be indicated in the claims. Description of the Preferred Embodiments [0074] Piezoelectric Element [0075] The design of the PE element of the invention is aimed at achieving several key properties not treated in prior art piezoelectric technology. More specifically, while utilization of piezoelectric technology for actuator and sensor applications has been widely discussed, developed and is at relatively wide use, practical utilization of piezoelectric as power generator is in it's infancy. The basic idea of utilizing the inherent characteristics of piezoelectric materials to harness physical motion, including coupling the piezoelectric to heart has been disclosed in patents and publications listed above. However, none of these deals with detailed design and construction as to meet specific characteristics set forth in the current invention, namely: small-size, lightweight power source and activated through physical motion of the device comprising the piezoelectric element. The scope of the design is to provide power output at high power density while being activated through minimal deflection force that is applied at low frequency of less than 3 Hz, typical for body organs, and in particular 1-3 Hz typical for the beating heart. The key design parameters of the piezoelectric element of the current invention are related to realization of a piezoelectric construct with minimal stiffness and maximal capacitance, both features enabling activation by minimal force, typically of few mN, achievement of low resonant frequency, and enabling the delivery of high electrical energy to charge the energy storage unit. [0076] Referring to the piezoelectric generator element of the present invention the basic design is based on a cantilever, bending type construction. In principle this type of construction is the most effective to enable operation at minimal resonant frequency and minimal damping affect with minimal activation force. Since the primary scope of the invention is harnessing the motion of the heart to utilize the generated energy for a variety of implanted medical devices, including but not limiting, cardiology related applications, the low resonant frequency is important due to the low frequency of heart beats, typically 70-80 bpm (1.2-1.3 Hz), or the even lower frequency of other body organs. Nevertheless, due to the relatively well-defined frequency of the heart, or other body organs, the piezoelectric cantilever could be designed to match the resonant frequency, thereby increasing the overall efficiency. The small activation force is important since the inertial activation is proportional to the inertial mass which is of few grams in general and most preferably of less than half gram. As it shall be ° disclosed in details elsewhere the activation ballast fixed to the flexing tip of the piezoelectric preferably consists of the energy storage unit and the power management unit thereby saving volume and weight. [0077] In particular, decreasing the structural stiffness leads to the largest gains in efficiency, followed by decreasing the mechanical damping and increasing the piezoelectric capacitance. [0078] Reference is now made to FIGS. 2 a and 2 b , presenting a unimorphic cantilever bender 20 a in balanced and loaded positions. The unimorphic cantilever bender 20 a comprises piezoelectric layer 60 and inactive vane 50 . Mechanical deformation of the piezoelectric element causes partial transformation of the mechanical energy to electrical energy, defined theoretically by the electro-mechanical coupling coefficient. The principle of piezoelectric cantilever operation is related to motion that causes the piezoelectric element to expand or contract, the deformation causing charge separation and formation of voltage across the two electrodes of the piezoelectric element, thereby resulting in an apparent charge on the piezoelectric capacitor, to be denoted C o . There are several cantilever constructions all causing piezoelectric longitudinal deformation upon flexing the free tip of the piezoelectric cantilever. In most practical cases of strip-type benders, the poling orientation is perpendicular to the longitudinal axes of the cantilever and the relative orientation of the deformation force applied on the cantilever relative to poling is 31 ( FIGS. 2 a and 2 b ). The most simple cantilever construction is a unimorphic where a piezoelectric (poled) layer is applied over an inert layer, forming a double-layer strip, similar to bimetals. When a force is applied on the free flexing tip of the piezoelectric cantilever, the bending leads to expansion of the outer layer, with the higher radius and contraction of inner layer. Thus upon periodic bending of the piezoelectric/metal cantilever the piezoelectric element is periodically stretched and contracted thereby resulting in alternatively charged electrodes across the piezoelectric ceramics, or equivalently periodically charged C o capacitor. At frequencies outside the resonance, piezoelectric ceramic transducers are fundamentally capacitors. Consequently, the voltage coefficients g ij are related to the charge coefficients d ij by the dielectric constant K i as, in a capacitor, the voltage V is related to the charge Q by the capacitance C. The equations are: [0000] Q=CV; d 31 =K 3 T ε 0 g 31 ; [0000] d 33 =K 3 T ε 0 g 33 ; d 15 =K 1 T ε 0 g 15 [0000] [0079] Because of the anisotropic nature of PZT ceramics, piezoelectric effects are dependent on direction. The 1, 2, and 3 indexes correspond to X, Y, Z of the classical right-hand orthogonal axis set). The direction of polarization (axis 3 ) is established during the poling process. Thus the polar, or 3 axis, is taken parallel to the direction of polarization within the ceramic. This direction is established during manufacturing by a high DC voltage that is applied between a pair of electrodes faces to activate the material. Piezoelectric coefficients with double subscripts link electrical and mechanical quantities. The first subscript gives the direction of the electrical field associated with the voltage applied, or the charge produced. The second subscript gives the direction of the mechanical stress or strain. [0080] At resonance, the dielectric constant will be reduced by the factor (1−k 2 ) where k is the coupling coefficient. [0081] Reference is now made to FIGS. 3 and 4 , presenting bi-morph and mono-block cantilever benders, respectively. By combining more than one piezo-layer 60 , it becomes possible to further increase the amount of transduction. For instance, a cantilever device can be created by placing two layers 60 of piezoelectric material provided with conducting layers 90 and disposed on alternative side of an inert, non-active support 50 like is illustrated schematically in FIG. 3 . Another and more efficient option is excluding the inactive layer and placing two active piezoelectric layers 60 on top of one-another, and by controlling the direction of polarization and the voltages such that when one layer contracts, the other expands ( FIG. 4 ). Exclusion of the inactive layer imparts an important feature to the resultant cantilever: reduction of the stiffness and consequently the accompanying features, as mentioned above. This is the specific design that has been chosen in the current invention as the most effective, however not limiting the other constructions known in the art that may be used while implementing the other supplementary design features to be disclosed herein. [0082] Another modification known in the field is replacing a single piezoelectric layer by several thin layers thereby creating what is known as a piezoelectric stack. Combining thin layers in parallel to form a piezoelectric stack increases the capacitance while still maintaining low deflection force. [0083] The relation of the open circuit voltage (OCV), the Capacitance and the Surface charge of a piezoelectric bi-morph are shown in the following formulae. [0084] Reference is now made to FIGS. 5 a and 5 b , presenting ceramic layers 60 of the piezoelectric stack can be electrically connected either in series or parallel, respectively. Ceramic polarity of the poling direction and the electrical connections for each of the configurations are shown. [0085] Parallel Connection of PE Layers [0000] V o =¾ g 31 *[F*L /( W*T )]*(1−( t/T ) 2 *A   (1a) [0086] Series Connection of PE Layers [0000] V o = 3/2 g 31 *[F*L /( W*T )]*(1−( t/T ) 2 *A   (1b) [0000] Q= 3 F*L 2 *d 31 /T 2   (2) [0000] C o =Q/V o   (3) [0000] C o =4 W*L*d 31 /( T*g 31 )   (4) [0087] Where [0088] V o is a generated OCV; [0089] W is a width; [0090] g 31 is a PE voltage constant; [0091] L is a length; [0092] F is an applied force; [0093] T—is an overall combined thickness; [0094] t is a vane/epoxy combined thickness; [0095] Q is a charge; [0096] d 31 is a PE strain constant [0097] A is an empirical weighing factor; [0098] C o is PE capacitance [0099] It can be seen in equations 1a or 1b that V o may reach maximum when t=0. Thus, reducing the thickness of the inactive vane, or eliminating it, as is in the mono-block design implemented in the current invention, results in maximal value of OCV, while keeping the other parameters constant. [0100] The capacitance of a dielectric can be expressed in the general equation: [0000] C o =ε r ε 0 x A/T;   (5) [0101] Where ε r is the relative dielectric contestant; ε 0 is the dielectric constant of air=8.85×10 −12 F/m; A is the capacitor area of the electrodes; T is the thickness of the dielectric material, or the distance between electrodes. [0102] Comparing equations 4 and 5 leads to [0000] d 31 /g 31 =ε r ε 0 x   (6) [0103] The maximal electrical energy of a PE element at a certain cantilever deflection (ΔX) is [0000] E o =½ CV 0 2   (7) [0104] Where E o is the maximal generated energy through the mechanical deformation at OCV conditions, meaning no current/energy is withdrawn from the piezoelectric construct; C is the piezoelectric capacitance and V 0 is the instantaneous Open Circuit Voltage at deformation/deflection ΔX. [0105] As can be seen in equation 4 maximal capacitance of a piezoelectric element at given dimensions (W, L) is inversely proportional to the thickness of the piezoelectric element (T). Thus, as shall be discussed elsewhere, the approach disclosed in this invention includes utilizing minimal thickness of the piezoelectric. Another parmeter affecting the capacitance is the d 31 /g 31 value. Since current invention relates to implantable applications where the temperature doesn't increase above 42° C., soft piezoelectric materials with low Currie temperature may be used without concern of thermal depolarization. It is within the scope of this invention to make use of the apparent correlation between the value of Currie temperature and the values of the dielectric constant or the strain and voltage constants (d 31 , g 31 ). Table 1 herein and FIGS. 6 and 7 illustrate the apparent characteristics of some commercial PZT material and they clearly demonstrate the benefits of utilizing materials with lower Currie temperature which have maximal d 31 /g 31 values. [0000] TABLE 1 PZT type Feature 5K 5H4E 5B 7A 5A Currie Temp. ° C. 160 230 330 350 365 Dielectric 6,200 3,800 2,350 410 1900 constant d31 PE strain pC/N 370 320 210 60 180 constant g31 PE voltage 10 −3 6.8 9.5 10.1 16.8 10.6 constant VM/N d31/g31 54 34 21 4 17 Y@ short 6.8 6.2 6.8 9.4 Young's Modulus [0106] One of methods increasing the capacitance (C o ) is by replacing a single piezoelectric layer, as described above, by several thinner layers that are connected in series thereby forming a “stack” of “n” parallel layers. If a piezoelectric element of thickness T is replaced by n layers each of thickness t, where t=T/n, and the n layers are wired in parallel, the resultant capacitance of the n layers may reach theoretically [0107] C t =C T x (T/t) 2 ; where C t and C T are the capacities of layers at thickness t and T respectively. Practically, when “t” is reduced to very low thickness of few microns, typically of 10-15 micron, as is the preferred case of the current invention, the extra thicknesses contributed by the electrodes and mostly by the adhesive material, combining the parallel layers may reduce “n” (n=T/t) by about 10%. Nevertheless, it is the scope of the current invention to utilize this feature to receive maximal electrical capacitance and maximal energy E o . The current invention relates to a piezoelectric mono-block, or other type of piezoelectric bending cantilever made of two stacks, each stack comprised of n parallel layers, typically t=10-15 microns while the value of n is preferably, but not limited to, 3-5. All layers within the stack are polarized in the same direction and each of the two stacks comprising the mono-block is attached to the other in such a manner that while applying voltage across each of the stacks, one stack contracts while the other extends thereby resulting in flexing of the mono-block. The same mechanism is being effective when flexing the free tip of the mono-block and generating the voltage. In case an inactive vane/substrate is used, a single piezoelectric stack may be used. [0108] As discussed above each of the stacks may be connected either in series or in parallel. The series bimorph element has one-fourth the capacitance and twice the voltage of the parallel element. Also, the series element has four times the impedance of the parallel element. While according to mathematics, both the series and parallel connections bear same instantaneous energy at OCV, marked differences between the series and parallel designs may be observed in the practical utilization of the energy generated by piezoelectric elements. It is the scope of the current invention to disclose that for the specific applications of activation of the piezoelectric bending cantilever element by an in-body organ like the heart, where low frequencies and low deflecting force are imposed and have to be met, the performance of the series connection is superior to the parallel. The superior performance of the series-connected element results from two mutually interrelated factors: (a) the fact that V o is proportional to the flexing force, and the series connection provides a higher voltage at a given activation force that is preferred since the basic target of the invention is to achieve maximal efficiency with minimal activation force and (b) considering a single vibration, it can be shown mathematically that maximal power extraction for a particular application occurs when the piezoelectric element delivers the required charging voltage at one half its OCV. An equivalent condition is that initial displacement be applied such that the piezoelectric OCV is twice the charging voltage of the energy storage unit. However, practically, when an initial displacement is applied to the piezoelectric element and electric power is generated by this initial displacement, the displacement thereafter is repeated in subsequent free vibrations. Thus, any subsequent free vibrations which are generated as a result of the initial displacement, a portion of the mechanical energy supplied to the piezoelectric element by the initial displacement is repeatedly converted into electrical energy during each vibration. Therefore, in comparison with the case of a kinetic activation in which subsequent free vibrations do not occur, in the case of inertial activation, the mechanical energy can be converted into electrical energy with a higher degree of efficiency. During these subsequent free vibrations, the displacement of the piezoelectric element gradually decreases after each vibration, and the unloaded voltage (OCV) corresponding to this displacement gradually decreases. For this reason, in order to generate electric power more efficiently utilizing the succeeding free vibrations resulting from an initial displacement, it is preferable that the piezoelectric OCV be higher than the above-described voltage related to a single deflection mode. The series connection is one of the disclosed means that enable the achievement of high efficiency with minimal activation force. Therefore, one of the means disclosed above is related to free vibrations, through which mechanical energy is repeatedly converted into electrical energy from the vibrator so as to generate power efficiently. [0109] The electro-mechanical coupling coefficient of a piezoelectric element is in general small and accordingly the ratio of the applied mechanical energy which is converted into electrical energy during any one displacement of the piezoelectric element is also relatively small. Ideally, the resonant frequency should be close to the expected input frequencies. This is not always the case. Sometimes it is hard to design a generator to meet the specification. The current invention overcomes this difficulty by utilizing a piezoelectric cantilever element of low stiffness. This is achieved by the use of thin layers which provide also the benefit of higher capacitance, thereby further increasing the energy. In general, the resonant frequency of any spring/mass system is a function of its stiffness and effective mass. Thus, when referring to the activation force, self- or resonant frequency, piezoelectric stiffness is an important parameter. According to the current invention, the stiffness is minimized by using layers of minimal thickness, making use of the mono-block design, such that the use of an inert, inactive vane that increases the stiffness is avoided. The low stiffness obtained by this design serves to bring the resonant frequency of the piezoelectric element into the frequency range of body organs, while concomitantly beneficially increasing capacitance. [0110] As discussed above, bending or deflection of the piezoelectric cantilever element places one of the ceramic layers under tension and the other layer under compression. As a result of the induced stresses, the element generates an output voltage that is proportional to the applied force. However, while reducing the thickness of the piezoelectric layer, upon bending the cantilever the strain per layer decreases accordingly, consequently resulting in a smaller Vo. Increasing the Vo through increased deflection imposes greater force which is in conflict of the basics disclosed in this invention. Current invention overcomes this drawback by implementing the series connection of the piezoelectric mono-block. [0111] In power generation systems utilizing cantilever piezoelectric elements, the mechanical activation originates from an external mechanical vibration or movement. The externally driven movement needs to be aligned with the deforming direction of the piezoelectric element. Efficient harnessing of the external motion by the piezoelectric cantilever cannot be achieved when the vector of the external motion is misaligned with the deforming direction of the piezoelectric element. Since orientation of the externally driven vibration may occasionally change with respect to the orientation of the originally installed, firm orientation of the piezoelectric element within the enclosure, the effectiveness of the harnessing of the motion may vary, and may go all the way down to zero. An even more complex problem arises from the presence of two independent forces or movements, such as the movement of a body organ or other object to which the piezoelectric generator is attached and its orientation in the gravitational field. [0112] The present invention provides a solution to the above outlined problems—to align the bending vector of the piezoelectric cantilever with the vectors of the external vibration or movement and the direction of the gravitational field. The invention provides a method to get efficient power generation which is independent of the direction of the externally driven vibration. [0113] Reference is now made to FIGS. 8 a - e, which present diagrams characterizing of operation mode 3-D harnessing mechanism. The figures illustrate the methods of installing the piezoelectric element within the enclosure as to enable harnessing the inertial energy of the motion, regardless of the orientation of the enclosure relative to the moving body and to gravitation. [0114] FIG. 8 a depicts rotational motion of an external ring 220 around an axis 225 , rotational and linear motions 210 and 200 , respectively. FIG. 8 b presents rotational motion of a n internal ring 230 . FIG. 8 c presents a piezoelectric element 240 provided at a flexing end 250 with a PCB device 260 adapted for energy storage and control. The device 260 comprises a ballast weigh (not shown) activated by external motion. FIGS. 8 d and 8 e depict rotational motions 270 and 290 of the element 240 fixed to the ring 280 . [0115] The advantage of the design is utilization of maximal length and width of the piezoelectric element, within a fixed volume, thereby providing maximal power output for a given fixed volume enclosure. [0116] Another option to harness the external motion, independently of its' orientation, is installing multiple piezoelectric cantilevers within the enclosure, in such a manner that whatever the orientation of the external motion is, its vector shall coincide with the bending orientation of one or several piezoelectric elements. [0117] In summary, the current invention discloses a method for generating maximal power while overcoming the following difficulties: [0118] a) low-amplitude activation forces; [0119] b) low activation frequencies; [0120] c) restricted volume available; and [0121] d) variable orientation of the external vibration or motion and the gravitational field with respect to the bending direction of the piezoelectric element. [0122] The above outlined operational parameters normally cause very low power output due to inefficient harnessing of the motion, followed by small deflection of the piezoelectric cantilever. The current invention addresses the problems by using thin multilayer stacks, the mono-block design and the series connection of the piezoelectric stacks, while ensuring efficient harnessing of the motion by introduction of the 3-D harnessing mechanism as discussed and illustrated above. [0123] Power Control and Energy Storage Unit [0124] In practical applications, it's important to fully exploit the available energy of the piezoelectric element. Maximal piezoelectric electrical energy has shown in equation (7) above: [0000] E o =½ CV 0 2 ;   (7) [0125] where E o is the maximal generated energy through the mechanical deformation of the piezoelectric element at Open Circuit Voltage (OCV) conditions, OCV meaning that no current/energy is withdrawn from the piezoelectric element(s); C is the piezoelectric capacitance and V 0 is the instantaneous OCV at deformation/deflection ΔX. [0126] It should be noted that self-vibration of the cantilever within the interval of externally enforced displacements (the original frequency of the body imposing the motion), though undergoing continuous damping, may still contribute considerable extra energy. [0127] The piezoelectric cantilever exhibits self vibrations within the interval of the externally imposed (forced) frequency. To achieve maximal transformation of the piezoelectric energy at OCV to available energy (utilized to charge the energy storage unit), it is important to adjust the voltage value and the interval during which the piezoelectric is connected to the parallel energy storage unit. Extraction of this potentially available energy depends on matching the piezoelectric Voltage and its' self-vibration frequency with the charging voltage of the coupled energy storage unit. The voltage control and switching is conducted by the power control unit by coupling the piezoelectric element to the energy storage unit. [0128] The piezoelectric element is connected to the energy storage unit through a power management element. The function of the power management element is rectifying the AC voltage of the piezoelectric to DC voltage, and at the same time switching the connection of the piezoelectric element and the distinct energy storage units according to the changing voltage values of the piezoelectric element and the properties of individual energy storage units. [0129] A variety of patents and literature refer to the method the piezoelectric energy is delivered to a parallel connected capacitor or rechargeable battery charged by the piezoelectric element and used to store the energy to be delivered upon demand. However, none of these publications makes a clear distinction between the capacitor and the battery in respect how each storage technology affects the conversion efficiency. Nevertheless, there is an inherent difference between the two, having a marked effect on efficiency, when transferring energy from the piezoelectric to charge a capacitor or to charge a battery. The current invention claims that for lightweight and small size devices use of a capacitor with specific value, to be discussed herein, provides considerable advantage over the use of a battery: (a) Batteries contain active chemical materials and hence their enclosure constitute substantial portion of their weight and volume (b) With miniature size batteries the passive components comprising the battery, like the case, constitute considerable fraction of weight and volume resulting in a sizeable decrease in the gravimetric and volumetric specific energies. (c) The equivalent serial resistance (ESR) of miniature batteries is relatively high leading to very small power density. (d) Any rechargeable battery system bears its very specific charging voltage within a specified and narrow voltage range. Since matching of the piezoelectric voltage and the charging voltage is of critical importance to achieve maximal efficiency, the fact that a battery imposes very specific condition for the charging voltage makes it very difficult to optimize the mechanical design parameters of the piezoelectric element which have to be optimized on one hand to the mechanical activation as to attain maximal conversion efficiency within the specific limitations of the application: minimal activation force and minimal footprint, and on the other hand to deliver the proper charging voltage to the battery. All of commercial rechargeable batteries require charging voltage >1.4V for aqueous systems and >3V for organic, lithium based systems. Thus in the case of using battery as the energy storage element the design of the piezoelectric element should meet these constraints or a proper DC converter should be used, in both cases imposing design parameters on the piezoelectric element that may be far from optimal for the mechanical conversion efficiency. [0134] As discussed above, the piezoelectric generator of the current invention refers to piezoelectric elements of minimal thickness providing maximal capacitance and at the same time enables activation by minimal force. However these design parameters impose relatively low OCV of the piezoelectric element. As discussed above, for optimal delivery of energy from the piezoelectric to the storage unit, the charging voltage of the storage unit should be no more than half (½) of the piezoelectric OCV. Thus it becomes clear that unless using an extra voltage converting element to ramp-up the Piezoelectric output to the charging voltage of the battery, the voltage of piezoelectric elements with OCV of <1.4V is not applicable at all while for effective charging the piezoelectric OCV should be ˜3V for aqueous battery systems and 7-8 V for organic, lithium battery systems. Reviewing the formulae of piezoelectric voltage and the relation of displacement-voltage-force, it becomes obvious that piezoelectric elements designed to meet the charging voltage of the batteries are far from the optimal parameters meeting the operating conditions set-forth in current application, it means minimal activation force at minimal footprint. [0135] In contrast to batteries, the properties of capacitors are not dictated by a specific chemistry, and capacitors may be chosen at any capacitance and within any voltage range suitable to the task. Furthermore, the charging voltage of capacitors is linear starting from zero, which, unlike batteries that require a specific charging voltage, allows direct energy extraction at any charge-state of the piezoelectric element. Also state-of-the-art polymer capacitors like Al or mostly preferred Ta, or any other composition, are available at miniature size and at light weight, not exceeding the weight of tens of milligrams. Also, the ESR of these small size capacitors is very low, in the milli-Ohm range, as opposed to the small size batteries bearing ESR of tens to hundreds Ohms. The low ESR of the capacitor reduces considerably the resistance-capacitance (RC), thereby shorting the time through which the charge flows from the piezoelectric to the capacitor contributing to higher transformation efficiency. As discussed, vibration damping of charged piezoelectric at OCV is greater than short-circuited. Self-vibration of the piezoelectric element within the period between displacements enforced by the external motion has a considerable contribution to the transformation efficiency. Thus to extend the self-vibration, or flexing of the piezoelectric element, not only the stiffness of the piezoelectric should be minimized as to reduce the mechanical damping, but also the rate at which the charge is delivered from the piezoelectric to the energy storage capacitor. This is related to minimal RC of the capacitor and the ΔV between the piezoelectric and the capacitor at charge. By using the architecture as disclosed in current invention, maximal optimization can be achieved. [0136] As discussed above, one of basic principles implemented in the generator design is utilizing thin-layer piezoelectric elements enabling small activation force, large piezoelectric capacitance and low damping factor. However, while this design provides clear benefits, it has a concomitant disadvantage in the relatively low voltage generated by the piezoelectric element. The current invention resolves this problem by making use of several independent capacitors, each charged to a low voltage which may be in any desired range. For miniature systems these values are typically between 0.1-2 V. Each of the capacitors is connected independently to the power management unit that switches among the individual capacitors and the piezoelectric element. [0137] Also, it should be considered that greater voltage difference between the piezoelectric and the capacitor shortens the time during which the current flows from the piezoelectric to the energy storage element. If the energy storage capacitance is small, the voltage will go up quickly, limiting the time the current flows and making it practically impossible to optimize the voltage ratios of the piezoelectric and the charged capacitor. However, if the capacitance is large it takes time for the voltage to build up and allows the current to flow for more time. Thus for maximal transformation efficiency the piezoelectric voltage, the capacitance and the frequency should be matched. The current approach enables maintaining optimal voltage difference between the piezoelectric and the individual capacitor at charge and its adjustment to the frequency. [0138] On the output side, the combination of individual capacitors enables also to avoid the use of a DC-DC converter, commonly used in many applications at the voltage input and output. The same or a separate power management element controls also the voltage that has to be delivered to the external load. By connecting in series the individual capacitors voltage ramp-up at output is possible. Connecting in parallel the capacitors enables delivery of relatively high charge (Q=I*t). By using a power management element and several individual capacitors, decoupling of the piezoelectric element and the energy storage unit is achieved. This design enables independent charging and discharging of separate capacitors thereby achieving optimal operation conditions for either the charge or the discharge mode. [0139] Another built-in operational concept is maintaining the voltage of each capacitor at relatively constant value matched to the piezoelectric voltage. This can be easily achieved by using the voltage control and switching power management element and periodically coupling the piezoelectric element to individual capacitors. Typical capacitance of piezoelectric cantilever mono-block bimorph element of 20 mm×8 mm×0.15 mm is about 1 micro-Farad. Such a bi-morph contains two series connected stacks, each stack comprising five parallel layers of about 15 microns thickness, resulting at 0.4 μF per layer or about 2 μF per stack. At series connection of the two stacks the resultant capacitance is 1 μF. [0140] Such a piezoelectric element is being coupled, through the power management unit with several, at least two, Ta (or other) solid state capacitors. Since for medical applications the operation temperature doesn't extend 37-42° C., no significant voltage de-rating is required to maintain a long service life. It is also well known to one skilled in the area, that maximal capacitance per unit volume or weight is achieved with capacitors operating at the low range of voltage. Thus very small capacitors with maximal specific capacitance may be used. Typical Ta sintered anode designed to operate at 2-6.3V and 85° C. provides 250-300 mFV/c.c. or 30-35 mFV/gr. Thus Ta anode pellet of 2-3V operating voltage and 220 μF will occupy 0.0015-0.0027 cc and weigh 12-23 milligram. Typical chip capacitor composed of polymer conductive counter electrode and enclosed within epoxy potting will occupy 0.002-0.003 cc and weight 20-30 milligram including termination. Thus even upon utilization of ten (10) individual capacitors the total volume and weight will not exceed 0.03 cc/0.3 gram respectively, while providing inherent advantage of charging each individual capacitor at preset voltage matched to the voltage supplied by the piezoelectric element. [0141] Since the ratio of the piezoelectric capacitor to the storage capacitor is at most 1:220 (<0.5%) and the intended vibration frequency is typically low, the rate of voltage rise upon charging the storage capacitor is relatively slow thereby making it simple to control the voltage of each storage capacitor within a relatively narrow range matching the voltage of the piezoelectric element. Also upon power delivery, the power management unit switches in series or parallel the individual capacitors as to control the voltage drop of each capacitor within a typical limit of <20% as to maintain the voltage of the capacitor for subsequent charging within the range of optimal ratio of piezoelectric and charging voltage. For instance, utilizing ten 2V/220 μF capacitors and maintaining their voltage within the range of 1.2V as the charge limit and 0.8V as the discharge limit, fits well to piezoelectric voltage of 2-3V in respect to optimal transformation efficiency of electrical energy between the piezoelectric and the storage capacitors on one hand, and for optimal conversion efficiency of the mechanical energy to electrical energy generated by the piezoelectric operated at the set-forth conditions of minimal stiffness, minimal size, etc. The same architecture of the ten capacitors may be charged/discharged within the range of 2.2V to 1.8V and coupled with piezoelectric generating 4-6V. It should be noted that instead of storage capacitor of 2-3V/220 μF, several capacitors of 2-3V/1 mF may be used and switched in same manner and according to same principles as described above. As mentioned, since the ESR of the Ta chip capacitors is relatively low, staying <1Ω even at series connection of several capacitors, no voltage drop upon pulse delivery or RC caused holdup of charging or discharging occurs. In this scheme, each capacitor may be kept at a different voltage value so as to match the variable voltage output of the piezoelectric generator. [0142] According to one design of the invention a number of capacitors of different charging voltage and capacitance are used so as to match the variable voltage output of the piezoelectric generator and provide more efficient charging under highly variable charging conditions and to provide further flexibility in output pulse delivery. [0143] During the damping period of the piezoelectric element, the voltage generated due to the self-vibrations of the piezoelectric element undergoes continuous decay. By implementing an array of independent capacitors, the piezoelectric element may be connected trough the power management unit to individual capacitors, each maintained within a specific and relatively narrow voltage range so as to match the decaying piezoelectric voltage to a capacitor at ½ the voltage value of the piezoelectric element. [0144] Reference is now made to FIGS. 9 a and 9 b time curves of the cardiac acceleration and the piezoelectrically generated voltage due to picking up the energy of cardiac contraction. It is shown that a train of non-rhythmic cardiac contractions is converted into a rhythmic train of voltage pulses. It should be appreciated that the rhythmicity of voltage pulses is achieved due to resonant properties of the piezoelectric element provided with the mechanical harnessing unit. [0145] Reference is now made to FIGS. 10 a and 10 b , presenting a geometric scheme of the micro-generator orientation relative to the heart; and a graph of the generated voltage in dependence on the geometric orientation, respectively. It is shown that the generated voltage depends on the geometric orientation.

This present invention provides a power supply for implanting into a patient's body and providing electricity to a load within the body, said power supply comprising an enclosure; adapted for optimizing an activating force by mechanisms of orienting thereof; the power supply further comprising (a) a piezoelectric micro-generator comprising (b) electrical energy storing means; (c) control unit adapted for managing charging and discharging said storing means said control unit further provided with means for decoupling said piezoelectric element from and connecting to said electrical energy storing means to increase efficiency of said power supply.

This application claims the benefit of Provisional Application Ser. No. 60/171,798, filed Dec. 22, 1999, for GLASS-FORMING LIQUID CRYSTALS, which is herein incorporated by reference. The U.S. Government has rights in this application pursuant to certain contracts and grants, including DE-FC03-92SF19460. FIELD OF THE INVENTION This invention relates to glass-forming liquid crystals (GLC) and, more particularly, to liquid crystalline compositions comprising compounds having a molecular weight in the range of about 1000 to 5000 grams per mole, and to optical devices formed therefrom. BACKGROUND OF THE INVENTION Liquid crystallinity is a consequence of spontaneous molecular self-assembly into a uniaxial, lamellar, helical, or columnar arrangement on a macroscopic scale. Because of their unique optical properties, liquid crystals are potentially useful as optical, photonic and optoelectronic devices (see for example Collings, P. J., and Patel, J. S., Handbook of Liquid Crystal Research , Oxford University Press, New York, 1997). In some of these applications, such as liquid crystal displays, the material functions in the fluid state where an applied field induces molecular reorientation with a response time on the order of milliseconds. With judiciously designed structural moieties, liquid crystals may also function in the solid state via a photonic or electronic stimulus with a much shorter response time. In addition, liquid crystals can be employed as passive devices in which no switching is involved. With the exception of applications in which molecular reorientation with an applied field is the basis, vitrified liquid crystals with an elevated glass transition temperature, T g , offer long-term mesomorphic stability as well as environmental durability. Whereas glass formation appears to be a privilege of liquid crystalline polymers, their generally high melt viscosity presents a major challenge to processing into large-area thin films. To combine ease of material processing with glass-forming ability in discrete molecular systems, extensive efforts have been made over the last two decades to develop glass-forming liquid crystals (GLCs) with well-defined structures having low to medium molecular weights (see for example Wedler, W. et al., 1991 , J. Mater. Chem., 1, 347; Attard, G. S. et al., 1992 , Chem. Mater., 4, 1246; Neumann, B. et al., 1997 , Adv. Mater., 9, 241; and Gresham, K. D. et al., 1994 , J. Polym. Sci: Part A: Polym. Chem., 32, 2039). Applications that have been explored with various GLCs include: optical data storage (see for example Ortler, R. et al., 1989 , Marromol. Chem., Rapid Commun, 10, 189; and Tamaoki, N. et al., 1997 , Adv. Mater., 9, 1102), optical nonlinearity (see for example Wang, H. et al., 1996 , Nature, 384, 244; and Loddoch, M. et al., 1994 , Appl. Phys. B, 59, 591), photochromism (see for example Natarajan, L. V. et al., 1991 , Macromolecules, 24, 6554), tunable filters for optical communication (see for example Morita, Y. et al., 1999 , Jpn. J. Appl. Phys., 38, Part.1, 95), and viewing angle compensation for displays (see for example Van de Witte, P. et al., 1999 , Liquid Crystals, 26, 1039). SUMMARY OF THE INVENTION The present invention is directed to a glass-forming liquid crystal composition comprising a compound having a molecular weight in the range of about 1000 to 5000 grams per mole, and having the formula (NEM) x —CYC—(CHI) y wherein CYC is a substituted cycloaliphatic core moiety containing about 24 to about 60 carbon atoms or a substituted aromatic core moiety containing about 6 to about 36 carbon atoms, NEM is a nematogenic pendant moiety, CHI is a chiral pendant moiety, x is 3 to 9, and y is 0 to 4. The invention is further directed to an optical device formed from the liquid crystal composition. BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1A-1D depict the molecular structures of liquid crystalline structures of compounds of the prior art and of the present invention, as well as the structures of nematogenic and chiral moieties included in the compounds. FIG. 2 is an FTIR spectrum measured for a nematic GLC film prepared from compound (VIII) of the present invention, which shows the linear dichroism of cyano bond stretching at 2225 cm −1 . FIG. 3 is a spectrum showing the reflectivity measured with unpolarized light incident on GLC films containing varying ratios of prior art compounds (IV) and (Elf). FIG. 4 depicts the X-ray diffraction patterns of compound (VIII) of the present invention. FIGS. 5-11 depict synthetic schemes for the preparation of the liquid crystalline compounds whose structures are shown in FIGS. 1 A- 1 D. DETAILED DESCRIPTION OF THE INVENTION Nematogenic and chiral moieties suitable for the practice of the present invention are discussed in U.S. Pat. Nos. 5,378,393 and 5,514,296, the disclosures of which are incorporated herein by reference. A nematogenic moiety contains a mesogenic group, which imparts liquid crystalline characteristics to the moiety and to compositions formed from it. This mesogenic group, which typically has a rod-shaped molecular structure (cf. H. Finkelmann, Angew. Chem. Int. Ed. Engl., 1987, vol. 26, pp. 816-824), is attached to a flexible link, which is typically an alkylene radical. To obtain a liquid crystalline composition with high optical birefringence, it is desirable that substituent groups in nematogenic moieties contain a multiplicity of conjugated unsaturated bonds; however, this conjugated unsaturation must not cause substantial absorption of light in the visible region by the liquid crystalline composition. Useful mesogenic groups for the practice of the present invention include: biphenyl and diphenylacetylene moieties described in the aforementioned paper by Finkelmann and by Wu et al., J. Appl. Phys., 1990, vol. 68, pp. 78-85; terphenyl groups described by Gray et al., J. Chem Soc., Chem. Commun., 1974, pp. 431-432; diphenylpyrimidines, as reported by Boller et al., Z. Naturforsch, 1978, vol. 33b, pp. 433-438; and 2,6-disubstituted naphthalene moieties, as described by Hird et al., Liquid Crystals, 1993, vol. 15(2) pp. 123-150. An acetylenic moiety, —C≡C—, and a carbonyloxyphenyl moiety are preferred groups. Suitable terminal substituents are included in the aforementioned papers of Finkelmann and Wu et al.; preferred terminal substituents are cyano or methoxy. A chiral moiety contains an optically active chiral group that includes at least one asymmetric carbon atom and is joined to a link, which is typically an alkylene radical. Compounds comprising the chiral nematic liquid crystalline compositions of the invention are esters, amides, acetals, or ketals. Esters and amides are formed by the reaction of reactive equivalents of carboxylic acids, for example, carboxyl halides, carboxylic anhydrides, and carboxylic esters derived from volatile, low molecular weight alcohols with alcohols and amines, respectively. The carboxylic acid reactive equivalent can be present in the reactant that provides the cycloaliphatic radical, with the reactants that provide the nematogenic and chiral moieties being amines or alcohols. Alternatively, the reactant that is the source of the cycloaliphatic radical can contain amino or hydroxy groups, with the carboxylic acid reactive equivalents being included in the reactants that provide the nematogenic and chiral moieties. Acetals and ketals can be formed by the acid-catalyzed condensation of alcohols containing nematogenic or chiral substituents with aldehydes or ketones, respectively, which are the source of the cycloaliphatic radicals. The aforementioned aldehydes or ketones can also include nematogenic or chiral substituents. A liquid crystalline composition of the present invention that includes a chiral moiety as described above exhibits selective reflection of visible and near infrared circular-polarized light of wavelength λ R . The selective reflection wavelength λ R can be varied by changes in the structure and concentration of the chiral moiety in the liquid crystalline composition. To achieve liquid crystalline compositions whose selective reflection wavelengths are in the visible region, it is necessary that the compositions exhibit adequate helical twisting power. The helical twisting power of a chiral liquid crystalline composition can be determined from the slope of the plot of the reciprocal of the selective reflection wavelength 1/λ R VS the mole fraction of the chiral component as the mole fraction approaches zero (cf. S. Krishnamurthy and S. H. Chen, Macromolecules, 1991, vol. 24, pp. 3481-3484; 1992, vol. 25, pp. 4485-4489). Helical twisting power of chiral nematic liquid crystalline compositions depends not only on the structure of the chiral moieties but also on the structure of the nematogentic moieties, in particular, the extent of the conjugated unsaturation and the length of the flexible link in these moieties (cf. S. Chen and M. L. Tsai, Macromolecules, 1990, vol. 23, pp. 5055-5058). Many applications of the chiral liquid crystalline compositions of the present invention require a pair of structurally related compositions, one capable of forming a right-handed and the other a left-handed helical structure, which enables them to selectively reflect right-handed and left-handed circular-polarized light, respectively. Using an enantiomeric pair of compounds to form two chiral moieties of opposite chirality, which are then combined with a common nematogenic moiety, provides a pair of liquid crystalline compositions capable of forming right- and left-handed helices. This is illustrated, for example, by the chiral nematic liquid crystalline copolymers containing chiral moieties prepared from R-(+)- and S-(−)-1-phenylethylamine that form helical structures of opposite handedness, as described in M. L. Tsai and S. H. Chen, Macromolecules, 1990, vol. 23, pp. 1908-1911. In accordance with the present invention, optically active compounds preferred for preparing chiral moieties as described above include the enantimomers of 1-phenylethanol, 1-phenylpropanol, 2-methoxy-2-phenylethanol, mandelic acid methyl ester, α-tetralol, 1-phenylethylamine, 1-cyclohexylethylamine, and 3-amino-ε-caprolactam, camphorcarboxylic acid, menthyloxacetic acid, 1-methyl-2 oxocyclohexanepropionic acid methyl ester, 2-phenylpropionic acid, and camphor. Especially preferred are the enantiomeric pairs of 1-phenylethanol and 1-phenylethylamine. CYC cycloaliphatic moieties useful in the present invention may include polyvalent radicals derived from any of the compounds listed in Table 1 in columns 4-5 of U.S. Pat. No. 5,378,393. Preferred polyvalent radicals are those derived from adamantane, bicyclooctene, cyclohexane, and cubane. The term aromatic core moieties in addition to those derived from benzene and naphthalene may also include heteroaromatic moieties such as those derived from furan and thiophene. Materials Synthesis and Purification Procedures All chemicals, reagents, and solvents were used as received from Aldrich Chemical Company or VWR Scientific with the following exceptions. Tetrahydrofuran (99%) was dried by refluxing over sodium in the presence of benzophenone until blue then distilled for use. Silica gel 60 (EM Science, 230-400 mesh) was used for liquid chromatography. Synthesis and purification of intermediates and final products were carried out following FIGS. 5-11. Experimental procedures are described in what follows. Cis, cis-cyclohexane-1,3,5-tricarboxylic acid, tris{3-[6′-(4″-cyanophenyl) 2′-naphthyloxy]-1-propyl ester}, (I) The synthesis and purification of this nematic GLC was reported in Chen et al., Liquid Crystals, 1997, 21, 683. 1-t-Butyldimethylsilyloxy-3,5-benzenedicarboxylic acid, (a) 5-Hydroxyisophthalic acid (9.11 g, 50.0 mmole) and t-butyldimethylsilyl chloride (25.2 g, 167 mmole) were dissolved in anhydrous N,N-dimethylformamide (55 ml). Upon adding imidazole (20.4 g, 300 mmole), the solution was stirred overnight before shaking with diethyl ether (200 ml) and water (600 ml). The organic layer was reduced in volume by evaporation to a clear oil, which was mixed with tetrahydrofuran (45 ml), water (30 ml), glacial acetic acid (30 ml) and acidified with 37% HCl solution. The reaction mixture was stirred for a couple of hours. Upon evaporating off THF, the solution was shaken with methylene chloride (200 ml) and water (200 ml). The organic was washed twice with water (200 ml each), and the insoluble product was collected by filtration. Additional product was collected by washing with water the solid residue from evaporating off the solvent. A total of 10.1 g (68%) of (a) was obtained with its structure validated by proton NMR spectroscopy. 2-(3′-Hydroxy-1′-propyloxy)-6-(4″-cyanophenyl)naphthalene, (b) The synthesis and purification of this nematic precursor was reported in Chen et al., Liquid Crystals, 1997, 21, 683. 1-t-Butyldimethylsilyloxy-3,5-benzenedicarboxylic acid, bis{3-[6′-(4″-cyanophenyl)-2′-naphthyloxy]-1-propyl ester}, (c) Intermediate (a) (1.80 g, 6.07 mmole), intermediate (b) (3.63 g, 12.0 mmole), and triphenylphosphine (3.29 g, 12.6 mmole) were dissolved in anhydrous tetrahydrofuran (80 ml). Upon addition of diethylazodicarboxylate, DEAD, (2.1 ml, 13.3 mmole), the solution was stirred overnight. The solid residue resulting from evaporation to dryness was mixed with methylene chloride, and the insolubles were filtered off. The crude product in the filtrate was purified by silica gel column chromatography with methylene chloride as the eluent to obtain (c) in 3.49 g (67%) with its structure validated by proton NMR spectroscopy. 1-Hydroxy-3,5-benzenedicarboxylic acid, bis{3-[6′-(4″-cyanophenyl)-2′-naphthyloxy]-1-propyl ester}, (d) Intermediate (c) (3.48 g, 4.0 mmole) was dissolved in tetrahydrofuran (30 ml) and acetone (5 ml) at room temperature. The solution was then chilled in an ice water bath. Tetrabutylammonium fluoride, TBAF, solution (1 M, 5 ml, 5.0 mmole) was added over 15 min with subsequent stirring for 30 min. The reaction was quenched with ammonium chloride (0.78 g, 14.5 mmole) in water (10 ml). After stirring for 10 min, the solution was shaken with methylene chloride (200 ml) and water (200 ml). The volume of the organic layer was reduced to 40 ml via evaporation. The solid product in 2.08 g (66%) was collected by filtration with its structure validated by proton NMR spectroscopy. Cis, cis-cyclohexane-1,3,5-tricarboxylic acid, tris{3,5-bis{3′-[6″-(4″′-cyanophenyl)-2″-naphthyloxy]-1′-propyloxycarbonyl}phenyl ester}, (II) Intermediate (d) (2.05 g, 2.63 mmole), cis,cis-1,3,5-cyclohexanetricarboxylic acid (0.19 g, 8.7 mmole), and triphenylphosphine (0.74 g, 2.83 mmole) were dissolved in anhydrous tetrahydrofuran (20 ml) and anhydrous N,N-dimethylformamide (10 ml). Diethyl-azodicarboxylate (0.45 ml, 2.85 mmole) was added to the solution over 5 min, and the reaction mixture was stirred for two days. Upon reducing the volume by evaporation, the reaction mixture was shaken with methylene chloride (100 ml) and water (100 ml). The organic layer was dried over anhydrous MgSO 4 , and the volume was reduced by evaporation. Upon column chromatography on silica gel using a gradient elution from methylene chloride to methylene chloride:acetone (30:1) with subsequent precipitation into ethanol, (II) was obtained in 0.40 g (18%). Proton NMR spectral data, δ (CD 3 Cl): 8.63-7.11 (m, 69H, aromatic), 4.62 (t, 12H, COOCH 2 CH 2 ), 4.23 (t, 12H, CH 2 CH 2 O), 2.92-2.63 (m, 6H, cis-cyclohexane ring), 2.34 (m, 6 H, CH 2 CH 2 CH 2 ), 1.80-1.98 (m, 3H, cis-cyclohexane ring). Anal. Calcd. for C 153 H 114 N 6 O 24 : C, 75.92; H, 4.75; N, 3.47. Found: C, 75.87; H, 4.88; N, 3.50%. 4-[(S)-(−)-1-phenylethyl]-4-[(2-hydroxyethoxy)-benzoyloxy]benzamide, (e) The synthesis and purification of this chiral precursor was reported in Katsis et al., Chem. Mater., 1999, 11, 1590. Exo, exo-bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic acid, tetrakis{3-[6′-(4″-cyanophenyl)-2′-naphthyloxy]-1-propyl ester}, (III), and exo, exo-Bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic acid, tris{3-[6′-(4″-cyanophenyl)-2′-naphthyloxy]-1-propyl ester}, mono (S)-(−)-2-{4′-[4″-(1′″-phenyl-ethylcarbamoyl)phenoxycarbonyl]phenoxy ethyl ester}, (IV) Intermediate (b), (1.00 g, 3.30 mmole), intermediate (e) (0.45 g, 1.12 mmole), all exo-bicyclo-[2.2.2.]oct-7-ene-2,3,5,6-tetracarboxylic acid (0.31 g, 1.10 mmole), and triphenylphosphine (1.21 g, 4.61 mmole) were added to anhydrous tetrahydrofuran (20 ml) and anhydrous N,N′-dimethylformamide (5 ml). Complete dissolution occurred upon addition of diethyl-azodicarboxylate (0.76 ml, 4.8 mmole). The reaction mixture was stirred overnight, and its volume was reduced by evaporation for precipitation into ethanol. The crude product was purified by column chromatography on silica gel with a gradient elution from methylene chloride to methylene chloride:acetone (20:1) followed by precipitation into ethanol to yield (III) in 0.29 g (18%) and (IV in 0.40 g (24%). (III): Proton NMR spectral data, δ (CD 3 Cl): 7.98-7.04 (m, 40 H, aromatic), 6.40 (m, 2H, olefinic), 4.33-4.12 (m, 8H, COOCH 2 CH 2 , exo), 4.04 (t, 8H, CH 2 CH 2 O), 3.39 (m, 2H, CH, bridgehead), 3.11 (s, 4H, CH, tertiary), 2.09 (m, 8H, CH 2 CH 2 CH 2 ). Anal. Calcd. for C 92 H 72 N 4 O 12 : C, 77.51; H, 5.09; N, 3.93. Found: C, 77.37; H, 4.83; N, 4.17%; (IP: Proton NMR spectral data, δ (CD 3 Cl): 8.12-7.04 (m, 43H, aromatic), 6.48-6.33 (m, 3H, olefinic and CONH), 5.38 (m, 1H, NHCH(CH 3 )), 4.44-3.99 (m, 16H, COOCH 2 CH 2 CH 2 O and COOCH 2 CH 2 O), 3.41 (d, 2H, CH, bridgehead), 3.13 (d, 4H, CH, tertiary), 2.12 (m, 6H, CH 2 CH 2 CH 2 ), 1.63 (d, 3H, CH(CH 3 )). Anal. Calcd. for C 96 H 78 N 4 O 15 : C, 75.48; H, 5.15; N, 3.67. Found: C, 74.88; H, 5.27; N, 3.90%. Bicyclo[2.2.2]oct-7-ene-(2,5)-exo-(3,6)-endo-tetracarboxylic acid, 3,6-dimethylester, (f) Exo,exo-bicyclo[2.2.2]-7-ene-tetracarboxylic dianhydride (10.0 g, 40 mmole) and sodium methoxide (7.00 g, 130 mmole) were added to anhydrous methanol (150 ml). Upon refluxing overnight, the solvent was removed by evaporation before adding water (30 ml). The solution was kept below 4° C. while the solution was acidified with HCl solution (2 M). The solid product was collected by filtration, yielding 3.5 g (28%), and its structure validated by proton NMR spectroscopy. Bicyclo[2.2.2]oct-7-ene-(2,5)-exo-(3,6)-endo-tetracarboxylic acid, (g) Intermediate (f) (2.60 g, 8.3 mmole) was dissolved in NaOH solution (10%, 20 ml). Upon refluxing for 2 h, the reaction mixture was acidified with HCl solution (2 M). The solid product was collected by filtration, yielding 1.0 g (42%), and its structure validated by elemental analysis and proton NMR spectroscopy. Bicyclo[2,2,2]oct-7-ene-2,5, -exo-3,6-endo-tetracarboxylic acid, tetrakis{3-[6′-(4″-cyanophenyl)-2′-naphthyloxy]-1-propyl ester}, (f) Intermediate (g) (0.15 g, 0.54 mmole), intermediate (b) (0.70 g, 2.31 mmole), dicyclohexylcarbodiimide, DCC, (0.54 g, 2.6 mmole), p-toluenesulphonic acid (10 mg) were dissolved in pyridine (6 ml). The reaction mixture was stirred at room temperature overnight before adding acetic acid (1 ml) to consume excess DCC. Upon filtering off solid residues, 50 ml water was added for acidification with HCl solution (2 M). The resulting solid was dissolved in methylene chloride (100 ml) for extraction with NaHCO 3 solution (10%, 100 ml×2) and water (100 ml×2). The organic layer was dried over anhydrous MgSO 4 . The crude product was purified by column chromatography on silica gel via a gradient elution from methylene chloride:acetone (200:1) to (50:1), yielding (p in 0.50 g (65%). Proton NMR spectral data, δ (CD 3 Cl): 7.98-7.04 (m, 40H, aromatic), 6.31 (m, 2H, olefinic), 4.35 (m, 4H, COOCH 2 CH 2 , endo), 4.23 (m, 4H, COOCH 2 CH 2 , exo), 4.07 (t, 4H, CH 2 CH 2 O, endo), 4.00 (t, 4H, CH 2 CH 2 O, exo), 3.57 (m, 2H, CH, bridgehead), 3.28 (m, 2H, CH, tertiary, endo), 3.02 (m, 2H, CH, tertiary, exo), 2.15 (m, 4 H, CH 2 CH 2 CH 2 , endo), 2.05 (m, 4H, CH 2 CH 2 CH 2 , exo). Anal. Calcd. for C 92 H 72 N 4 O 12 : C, 77.51; H, 5.09; N, 3.93. Found: C, 77.21; H, 5.29; N, 3.84%. Bicyclo[2,2,2]oct-7-ene-2,5-exo-3,6-endo-tetracarboxylic acid, tetrakis{3,5-bis{3′-[6″-(4″′-cyanophenyl)-2″-naphthyloxy]-1′-propyloxycarbonyl}phenyl ester}, (VI) Dry tetrahydrofuran (25 ml) was added to intermediates (d) (1.00 g, 1.33 mmole) and (g) (0.092 g, 0.32 mmole), p-toluenesulphonic acid/4-dimethylaminiopyridine salt (0.10 g, 0.34 mmole), and dicyclohexylcarbodiimide (0.31 g, 1.48 mmole). Upon stirring overnight, the insolubles were filtered off, and the filtrate was evaporated to dryness. The solid residue was shaken with methylene chloride (100 ml) and dilute acetic acid solution(100 ml). The organic layer was washed sequentially with water, saturated NaHCO 3 solution, water, and saturated brine (100 ml each) and then dried over anhydrous MgSO 4 . The solution was reduced to 25 ml in volume afterwards. After removing the insolubles, the crude product was purified by silica gel column chromatography with methylene chloride:acetone (30:1) as the eluent. Further purification was accomplished by precipitation into ethanol to yield (VI) in 0.84 g (78%). Proton NMR spectral data, δ (CD 3 Cl): 8.66-7.04 (m, 92H, aromatic), 6.51 (m, 2H, olefinic), 4.62-4.40 (m, 16H, COOCH 2 CH 2 , endo and exo), 4.35-4.16 (m, 16H, CH 2 CH 2 O, endo and exo), 4.10 (m, 2H, CH, bridgehead), 3.86 (m, 2H, CH, tertiary, endo), 3.55 (m, 2H, CH, tertiary, exo), 2.40-2.10 (m, 16 H, CH 2 CH 2 CH 2 , endo and exo). Anal. Calcd. for C 204 H 148 N 8 O 32 : C, 76.01; H, 4.63; N, 3.48. Found: C, 75.62; H, 4.81; N, 3.61%. 1,3,5-Benzenetricarboxylic acid, tris{3-[6′-(4″-cyanophenyl)-2′-naphthyloxy]-1-propyl ester}, (VII) Benzene-1,3,5-tricarbonyl trichloride (0.28 g, 1.08 mmol), intermediate (b) (1.00 g, 3.3 mmol), and 4-dimethylaminopyridine (0.80 g, 6.6 mmol) were dissolved in 15 ml anhydrous THF. The solvent was removed by evaporation after 3 h reflux. The residue was dissolved in CH 2 Cl 2 for washing sequentially with HCl solution (1 M), NaHCO 3 solution (10%), and water. The organic layer was dried over anhydrous MgSO 4 . Further purification was carried out by silica gel column chromatography with methylene chloride as the eluent to yield (VII) in 0.80 g (73%). Proton NMR spectral data, δ (CD 3 Cl): 8.90-7.11 (m, 33H, aromatic), 4.70 (t, 6H, COOCH 2 CH 2 ), 4.26 (t, 6H, CH 2 CH 2 O), 2.30 (m, 6H, CH 2 CH 2 CH 2 ). Anal. Calcd. for C 69 H 51 N 3 O 9 : C, 77.73; H, 4.82; N, 3.94. Found: C, 77.29; H, 4.86; N, 3.85%. 1,3,5-Benzenetricarboxylic acid, tris{3,5-bis{3′-[6″-(4″′-cyanophenyl)-2″-naphthyloxy]-1′-propyloxycarbonyl}phenyl ester}, (VIII) Intermediate (d) (0.50 g, 0.66 mmole), 1,3,5-benzenetricarbonyl chloride (0.055 g, 0.21 mmole), and 4-dimethylaminopyridine (0.16 g, 1.3 mmole) were dissolved in anhydrous tetrahydrofuran (25 ml). Upon refluxing for 3 h, the reaction mixture was poured into water (70 ml). The solid was collected by filtration for silica gel column chromatography with a gradient elution from methylene chloride to methylene chloride:acetone (25:1). Compound (VIII) was obtained in 0.30 g (59%). Proton NMR spectral data, δ (CD 3 Cl): 9.52-7.11 (m, 72H, aromatic), 4.66 (t, 12H, COOCH 2 CH 2 ), 4.28 (t, 12H, CH 2 CH 2 O), 2.39 (m, 12H, CH 2 CH 2 CH 2 ). Anal. Calcd. for C 153 H 108 N 6 O 24 : C, 76.11; H, 4.51; N, 3.48. Found: C, 76.03; H, 4.62; N, 3.53%. 2-(2-Hydroxyethoxy)-6-bromonaphthalene, (h) To a solution of 6-bromo-2-naphthol (15.1 g, 67.7 mmol), 2-bromoethanol (10.11 g, 80.9 mmol) in N,N-dimethylformamide (60 ml) was added a solution of KOH (5.41 g, 81.9 mmol) and KI (0.37 g, 2.20 mmol) in water (10 ml). Upon stirring at 85° C. for 4 hours, the reaction mixture was filtered. The filtrate was shaken with diethyl ether (400 ml) and water (400 ml). The organic layer was washed with 2% KOH (100 ml water). The solvent was evaporated off to obtain crude product. Recrystallization from a mixed solvent of methanol (20 ml) and water (200 ml) yielded (h) in 10.0 g (55%). Proton-NMR spectral data (CDCl 3 ), δ (ppm): 2.16 (t, HOCH 2 , 1H), 4.10 (m, HOCH 2 CH 2 , 2H), 4.22 (t, ArOCH 2 CH 2 ,2H), 7.10-7.95 (m, aromatic, 6H). 2-[6′-(4″-Cyanophenyl)-2′-naphthyl]-1-ethanol, (i) A biphasic mixture of benzene (52 ml), ethanol (7 ml) and 2M Na 2 CO 3 (59 ml) was sparged with argon for 20 minutes before adding 4-cyanobenzeneboronic acid (3.85 g, 26.2 mmol), (h) (6.619 g, 24.78 mmol) and triphenylphosphine (0.65 g, 0.55 mmol). The reaction mixture was refluxed under argon overnight. Evaporation to dryness resulted in crude product, which was purified by recrystallization from ethyl acetate to obtain (i) in 5.32 (74%). Proton-NMR spectral data (CDCl 3 ), δ (ppm): 4.08 (t, HOCH 2 CH 2 , 2H), 4.26 (t, ArOCH 2 CH 2 , 2H), 7.21-8.00 (m, aromatic, 1 OH) 1-t-Butyldimethylsilyloxy-3,5-benzenedicarboxylic acid, bis{2-[6′-(4″-cyanophenyl)-2′-naphthyloxy]-1-ethyl ester}, (j) Intermediate (i) (4.289 g, 14.82 mmol), 1-t-butyldimethylsilyloxy-3,5-benzene-dicarboxylic acid (2.179 g, 7.85 mmol), and triphenylphosphine (4.099 g, 15.63 mmol) were dissolved in dry tetrahydrofuran (60 ml) under argon then chill in an ice bath. Diethyl azodicarboxylate, DEAD, (2.6 ml, 16.5 mmol) was slowly added to the solution, which was then stirred overnight at room temperature. The reaction mixture was evaporated to dryness, and the solid residue was dissolve in methylene chloride for silica gel column chromatography with methylene chloride as the eluent to yield (j) (4.68 g, 76%). Proton-NMR spectral data (CDCl 3 ), δ (ppm): −0.04 (s, Si(CH 3 ) 2 , 6H), 0.83 (s, Si(C(CH 3 ) 3 , 9H), 4.44 (ArOCH 2 CH 2 , 4H), 4.69 (t, COOCH 2 CH 2 , 4H), 7.18-8.26 (m, aromatic, 23H) 1-Hydroxy-3,5-benzenedicarboxylic acid, bis{2-[6′-(4″-cyanophenyl)-2′-naphthyloxy]-1-ethyl ester}, (k) Intermediate (j) (5.8 g, 6.9 mmol) was dissolved in a mixed solvent of tetrahydrofaran (50 ml) and acetone (10 ml). The solution was chilled in an ice bath before adding tetrabutylammonium fluoride, TBAF, (1 M in THF, 8.5 ml) over 7 minutes. The reaction was quenched after 45 minutes by adding a solution of ammonium chloride (0.65 g, 12 mmol) in water (6.5 ml). The solution was then shaken with methylene chloride (200 ml) and water (100 ml). The organic portion was washed with water (100 ml×2) and saturated brine (50 ml) and then dried over anhydrous MgSO 4 . The crude product resulting from evaporating off the solvent was purified by recrystallization from acetone and then from methylene chloride to yield (k) (4.15 g, 83%). Proton-NMR spectral data (DMSO-d 6 ), δ (ppm): 4.26 (ArOCH 2 CH 2 , 4H), 4.67 (t, COOCH 2 CH 2 , 4H), 7.15-8.23 (m, aromatic, 23H), 10.31 (s, HOAr, 1H) Cis-cis-1,3,5-cyclohexanetricarboxylic acid, tris{3,5-bis{2′-[6″-4′″-cyanophenyl)-2′-naphthyloxy]1′-ethyloxycarbonyl}phenyl ester}, (IX) A reaction mixture was prepared by dissolving (k) (0.997 g, 1.39 mmol), cis-cis-1,3,5-cyclohexanetricarboxylic acid (0.100 g, 0.46 mmol), and p-toluenesulphonic acid 4-dimethylaminopyridine complex (0.0544 g, 0.18 mmol) in dry tetrahydrofuran (10 ml). Upon adding N,N′-dicyclohexylcarbodiimide (0.397 g, 1.94 mmol), the reaction mixture was refluxed for 36 hours. Crude product was collected by precipitation of a methylene chloride solution into ethanol. Purification was accomplished by silica gel column chromatography with a gradient elution from methylene chloride to methylene chloride:acetone (30:1). The product was further purified by precipitation from a methylene chloride solution into ethanol to obtain (IX) (0.489 g, 46%). Proton-NMR spectral data (CDCl 3 ), δ (ppm): 1.85-2.05 (m, cyclohexane, 3H), 2.60-2.90 (m, cyclohexane, 6H), 4.43 (t, ArOCH 2 CH 2 , 12H), 4.79 (t, COOCH 2 CH 2 , 12H), 7.15-8.65 (m, aromatic, 69H). Analysis calculated for C 147 H 102 N 6 O 24 : C, 75.57; H, 4.40; N, 3.60. Found C, 75.18; H, 4.42; N, 3.63. Bicyclo[2.2.2.]oct-7-ene-(2,5)exo-(3,6)-endo-tetracarboxylic acid, tetrakis{3,5-bis{2′-[6″-(4′″-cyanophenyl)-2″-naphthyloxy]1′-ethyloxycarbonyl}phenyl ester}, (X) Intermediate (k) (0.849 g, 1.17 mmol), bicyclo[2.2.2.]oct-7-ene-(2,5)exo-(3,6)-endo-tetracarboxylic acid (0.0836 g, 0.29 mmol), N,N′-dicyclohexylcarbodiimide (0.293 g, 1.42 mmol) and p-toluenesulphonic acid 4-dimethylaminopyridine complex (0.0723 g, 0.24 mmol) were dissolved in dry tetrahydrofuran (10 ml) and dry N,N′-dimethyl-formamide (4 ml). The reaction mixture was stirred overnight under argon at room temperature followed by shaking with methylene chloride (50 ml) and dilute acetic acid (50 ml). The organic portion was washed with water (25 ml) and saturated NaHCO 3 (25 ml) before drying over anhydrous MgSO 4 . The crude solid product resulting from evaporating off the solvent was purified by silica gel column chromatography with a gradient elution from methylene chloride:hexanes (24:1) to methylene chloride:acetone (30:1). The product was further purified by precipitation from a methylene chloride solution into ethanol to obtain (X) (0.46 g, 50%). Proton-NMR spectral data (CDCl 3 ), δ (ppm): 3.50-4.05 (m, bicyclooctene endo-exo, 8H), 4.25-4.85 (m, COOCH 2 CH 2 OAr, 32H), 7.05-8.70 (m, aromatic, 92H). Analysis calculated for C 196 H 132 N 8 O 32 : C, 75.67; H, 4.28; N, 3.60. Found C, 75.19; H 14.41 ; N, 3.75. 2-(3′-p-Toluenesulphonyl-1′-propyloxy)-6-(4″cyanophenyl)naphthalene, (l) 2-(3′-Hydroxy-1′-propyloxy)-6-(4″ cyanophenyl)naphthalene (2.872 g, 9.47 mmol), was dissolved in dry pyridine (15 ml) under argon. The solution was then chilled in an ice water bath before quickly adding p-toluenesulphonyl chloride (5.1 g, 26 75 mmol). After chilling in a cold bath for 5 minutes, the reaction mixture was stirred at room temperature for 4 hours before pouring into vigorously stirred ice water (150 ml). The crude solid product was washed with water and then recrystallized from a mixed solvent of ethanol (50 ml) and acetone (120 ml) to obtain (1) (3.38 g, 78%). Proton-NMR spectral data (CDCl 3 ), δ (ppm): 2.21 (p, CH 2 CH 2 CH 2 , 2H), 2.31 (s ArCH 3 , 3H), 4.11 (t, ArOCH 2 CH 2 , 2H), 4.32 (t, SO 3 CH 2 CH 2 , 2H), 7.05-8.00 (m, aromatic, 14H) 3,4,5-Trihydroxybenzoic acid 2-hydroxy-ethyl ester, (m) A mixture consisting of ethylene glycol (105 g, 1.11 mol), gallic acid (28.5 g, 168 mmol), and concentrated H 2 SO 4 (10 drops) was stirred at 90° C. overnight before mixing with ice water (1500 ml). Upon adding NaCl (100 g), the solution was extracted with ethyl acetate (150 ml×4). The combined organic portion was evaporated to dryness to obtain (m) (9.98 g, 28%). Proton-NMR spectral data (DMSO-d 6 ), δ (ppm): 3.64 (t, HOCH 2 CH 2 , 2H), 4.15 (t, ArOCH 2 CH 2 , 2H), 6.93 (s, aromatic, 2H) 3,4,5-Tris{3′-[6″-(4′″-cyanophenyl)-2″-naphthyloxy]propyloxy}benzoic acid, hydroxyethyl ester, (n) A solution containing (l) (1.629 g, 3.56 mmol), (m) (0.254 g, 1.18 mmol), and finely ground potassium carbonate (0.504 g, 3.64 mmol) with a catalytic amount of potassium iodide in a mixed solvent of acetone (16 ml), N,N-dimethylformamide (6 ml) and water (0.5 ml) was refluxed for 2 days. Upon reducing the volume via evaporation, the crude product resulted from precipitation into dilute HCl (100 ml). The filtrate was shaken with diethyl ether (100 ml) followed by washing with NaHCO 3 (50 ml) and saturated brine. Upon evaporating off ether, the crude product was purified by silica gel column chromatography, with a gradient elution from methylene chloride to methylene chloride:acetone (15:1). Further purification was accomplished by recrystallization from a mixed solvent of tetrahydrofuran (5 ml) and acetone (25 ml) to obtain (n) (0.65 g, 51%). Proton-NMR spectral data (DMSO-d 6 ), δ (ppm): 2.04-2.30 (m, CH 2 CH 2 CH 2 , 6H), 3.70 (HOCH 2 CH 2 , 2H), 4.10-4.34 (m, ArOCH 2 CH 2 CH 2 OAr and COOCH 2 CH 2 , 14H), 7.00-8.19 (m, aromatic, 32H) Cis-cis-1,3,5-cyclohexanetricaroxylic acid, tris{2-{(3′,4′,5′-tris{3″-[6′″-(4″″-cyanophenyl)-2 ′″-naphthyloxy]-1″-propyloxy)benzenecarbonyloxy}ethyl}ester, (XI) Intermediate (n) (0.425 g, 0.40 mmol), cis-cis-1,3,5-cyclohexanetricarboxylic acid (0.0441 g, 0.20 mmol), and triphenylphosphine (0.1834 g, 0.69 mmol) were dissolved in dry tetrahydrofuran (10 ml) and dry N,N-dimethylformamide (4 ml). After addition of DEAD (11.3 ml, 72 mmol), the reaction mixture was stirred overnight under argon at room temperature. Upon reducing the volume by evaporation, the crude product resulted from precipitation into cold ethanol. Purification was accomplished by silica gel column chromatography followed by precipitation from a methylene chloride solution into ethanol to obtain (XI) (0.061 g, 15%). Proton-NMR spectral data (CDCl 3 ), δ (ppm): 1.40-1.60 (m, cyclohexane, 3H), 2.15-2.40 (m, overlap of cyclohexane and CH 2 CH 2 CH 2 , 24H), 4.09-4.45 (ArOCH 2 CH 2 CH 2 OAr and COOCH 2 CH 2 , 48H), 7.00-7.90 (m, aromatic, 96H). Analysis calculated for C 216 H 171 N 9 O 30 : C, 76.92; H, 5.11; N, 3.74. Found C, 76.57; H, 5.15; N, 3.23. 4-(t-Butyldimethylsilyloxy)benzoic acid, (o) 4-Hydroxybenzoic acid (4.009 g, 28.96 mmol) and tert-butyldimethylsilyl chloride (9.984 g, 66.24 mmol) were dissolved in dry N,N-dimethylformamide (21 ml) containing imidazole (8.653 g, 127.1 mmol). Upon stirring for 10 hours under argon, the reaction mixture was shaken with diethyl ether (130 ml) and water (130 ml). The organic portion was washed with water (60 ml×2). The crude product resulting from evaporating to dryness was dissolved in tetrahydrofuran (32 ml). Methanol (96 ml) and a solution of potassium carbonate (6.40 g, 46.31 mmol) in water (50 ml) were added. The mixture was then stirred for 1 hour. The volume was reduced by half by evaporation before adding a saturated brine (96 ml) followed by acidification with 1M KHSO 4 . The aqueous portion was washed times with diethyl ether (100 ml×3), and the organic portion was evaporated to dryness. Recrystallization from a mixed solvent of water (200 ml), ethanol (75 ml) and acetone (20 ml) yielded (o) (4.61 g, 63%). Proton-NMR spectral data (acetone-d 6 ), δ (ppm): 0.10 (s, Si(CH 3 ) 2 , 6H), 1.02 (s, Si(C(CH 3 ) 3 , 9H), 6.99 (d, aromatic, 2H), 7.95 (d, aromatic, 2H) 4-(t-Butyldimethylsilyloxy)benzoic acid, 3,5-bis{3′-[6″-(4″′-cyanophenyl)-2″-naphthalyoxy]-1′-propyloxycarbonyl}phenyl ester, (p) A reaction mixture consisting of (d) (0.998 g, 1.33 mmol), 4-(t-butyldimethyl-silyloxy)benzoic acid (0.382 g, 1.51 mmol), and N,N′-dicyclohexylcarbodiimide (0.399 g, 1.93 mmol), p-toluenesulphonic acid 4-dimethylaminopyridine complex (0.11 g, 0.37 mmol), dry tetrahydrofuran (20 ml) was refluxed overnight. Solid residues were filtered off, and the filtrate was evaporated to dryness. The crude product was purified by silica gel column chromatography with methylene chloride:acetone (50:1) as the eluent to obtain (p), (0.85 g, 65%). Proton-NMR spectral data (CDCl 3 ), δ (ppm): 0.25 (s, Si(CH 3 ) 2 , 6H), 1.02 (s, Si(C(CH 3 ) 3 , 9H), 2.38 (p, CH 2 CH 2 CH 2 , 4H), 4.25 (t, ArOCH 2 , 4H), 4.62 (t, COOCH 2 CH 2 , 4H), 6.90-8.85 (m, aromatic, 27H) Hydroxybenzoic acid, 3,5-bis{3′-[6″-(4″′-cyanophenyl)-2″-naphthalyoxy]-1″-propyloxycarbonyl}phenyl ester, (q) Intermediate (p) (0.80 g, 0.81 mmol) was dissolved in tetrahydrofuran (10 ml) and chilled in an ice/water/salt bath before adding TBAF (1 M in THF, 1 ml) over 5 minutes. Upon stirring for 45 minutes, the reaction was quenched with ammonium chloride (0.22 g, 4.11 mmol) in water (1 ml). Stirring was continued for additional 15 minutes before shaking with methylene chloride (50 ml) and water (25 ml). The organic portion was washed with water (25 ml×2) before drying over anhydrous MgSO 4 . Upon evaporating off the solvent, the crude product was recrystallized from tetrahydrofuran and then from acetone to obtain (q), (0.70 g, 78%). Proton-NMR spectral data (DMSO-d 6 ), δ (ppm): 2.22 (p, CH 2 CH 2 CH 2 , 4H), 4.25 (t, ArOCH 2 , 4H), 4.50 (t, COOCH 2 CH 2 , 4H), 6.85-8.42 (m, aromatic, 27H) Cis-cis-1,3,5-cyclohexanetricaroxylic acid, tris{4-(3′,5′-bis{3″-[6″′-(4″′-cyanophenyl)-2″′-naphthyloxy]-1″-propyloxycarbonyl}-phenyloxycarbonyl}phenyl}ester, (XII) Intermediate (q) (0.651 g, 0.75 mmol), cis-cis-1,3,5-cyclohexanetricarboxylic acid (0.0531 g, 0.25 mmol), and N,N′-dicyclohexylcarbodiimide (0.20 g, 0.97 mmol) were dissolved in dry tetrahydrofuran (10 ml) under argon. Upon adding 4-pyrrolidinopyridine (0.12 g, 0.08 mmol), the reaction mixture was stirred overnight at room temperature. Solid residues were removed, and the filtrate was evaporated to dryness. The crude product was dissolved in methylene chloride (50 ml) and then shaken with dilute acetic acid (25 ml). The organic portion was washed with water (25 ml×2) and then dried over anhydrous MgSO 4 . Further purification was accomplished by silica gel column chromatography, with a gradient elution from methylene chloride methylene chloride:acetone (30:1), followed by precipitation from a methylene chloride solution into methanol to obtain (XII) (0.149 g, 40%). Proton-NMR spectral data (CDCl 3 ), δ (ppm): 1.85-2.05 (m, 3H, cyclohexane), 2.38 (p, CH 2 CH 2 CH 2 , 12H), 2.65-3.00 (m, cyclohexane, 6H) 4.26 (t, ArOCH 2 CH 2 , 12H), 4.70 (t, COOCH 2 CH 2 , 12H), 7.10-8.74 (m, aromatic, 81H). Analysis calculated for C 174 H 126 N 6 O 30 : C, 75.15; H, 4.57; N, 3.02. Found C, 74.95; H, 4.70; N, 3.13. 3-(4′-cyano-p-terphenyloxy)-1-propanol, (r), and 3-[6′-(4-cyanophenyl) 2′-naphthyloxy]-1-propanol, (b), were synthesized following the procedures reported previously. 5-(4-Carboxy-2-nitrophenoxy-1,3-Benzenedicarboxylic acid, tris[3-(4′-cyano-p-terphenyloxy)-1-propyl]ester, (XIII) DEAD (0.31 ml, 1.97 mmol) was added dropwise to a solution containing 5-(4-carboxy-2-nitrophenoxy-1,3-benzenedicarboxylic acid (158 mg, 0.455 mmol), (r) (500 mg, 1.52 mmol), and triphenylphosphine (520 mg, 1.98 mmol) in 60 ml anhydrous THF. Upon stirring overnight at room temperature, the reaction mixture was poured into 400 ml methanol, affording a white precipitate collected by filtration and then dissolved in 200 ml methylene chloride. The resulting solution was washed with 10% NaHCO 3 (200 ml×2) and then water (200 ml×2) before drying over anhydrous MgSO 4 . Further purification was accomplished by silica gel column chromatography methylene chloride:acetone (100:1) as the eluent, yielding (XIII) (400 mg, 69%). Proton NMR spectral data (CD 3 Cl), δ (ppm): 8.67-6.99 (m, 42H, aromatic H), 4.61 (t, 6 H, COOCH 2 CH 2 ), 4.19 (t, 6H, CH 2 CH 2 O), 2.32 (q, 6H, CH 2 CH 2 CH 2 ). Anal. Calcd. for C 81 H 60 N 4 O 12 : C, 75.92; H, 4.72; N, 4.37. Found: C, 75.84; H, 4.82; N, 4.32%. 5-(4-Carboxy-2-nitrophenoxy-1,3-Benzenedicarboxylic acid, tris{3-[6′-(4-cyanophenyl) 2′-naphthyloxyl]-1-propyl}ester, (XIV) The same procedure as compound (XIII) was followed to produce (XIV) (69%) using Intermediate (b) instead of (r). Proton NMR spectral data (CD 3 Cl), δ (ppm): 8.65-6.99 (m, 36H, aromatic H), 4.63 (m, 6H, COOCH 2 CH 2 ), 4.27 (m, 6H, CH 2 CH 2 O), 2.35 (m, 6H, CH 2 CH 2 CH 2 ). Anal. Calcd. for C 75 H 54 N 4 O 12 : C, 74.86; H, 4.52; N, 4.66. Found: C, 75.04; H, 4.61; N, 4.63%. N-[3-(6′-bromo-2′-naphthoxy)-propyl/]-phthalimide, (s) To a solution of 6-bromo-2-naphthol (15.0 g, 67.0 mmol) and N-(3-bromo-propyl)-phthalimide (18.0 g, 67 mmol) in 250 ml DMF, was added 11.0 g K 2 CO 3 and 1.0 g KI. The resulting suspension was stirred at 80° C. for 24 hours. The reaction mixture was then poured into 400 ml cold water, affording a white precipitate collected by filtration and then dissolved in 200 ml methylene chloride. The solution was washed with 10% NaHCO 3 (200 ml×2), water (200 ml×2), and then dried with anhydrous MgSO 4 , Recrystallization from ethyl acetate yielded (s) (18.0 g, 65%). Proton NMR spectral data (CD 3 Cl), δ (ppm): 7.90-6.98 (m, 10H, aromatic H), 4.16 (t, 2 H, NCH 2 CH 2 CH 2 ), 3.96 (t, 2H, CH 2 CH 2 CH 20 ), 2.24 (q, 2H, CH 2 CH 2 CH 2 ). N-{3-[6′-(4″ cyano-phenyl)-2′-naphthoxy]-propyl}-phthalimide, (t) Triphenylphosphine (1.90 g, 1.63 mmol) was added to a deoxygenated emulsion consisting of compound (s) (22.0 g, 53.7 mmol), 4-cyano-benzene-boronic acid (8.0 g, 54.4 mmol) in benzene (160 ml), and 2 M Na 2 CO 3 (160 ml). After reflux for 24 hours, the reaction mixture was cooled to room temperature. The crude solid product was dissolved in a minimum amount of hot chloroform for precipitation from methanol, yielding (t) (15.0 g, 65%). Proton NMR spectral data (CD 3 Cl), δ (ppm): 8.02-7.00 (m, 14H, aromatic H), 4.20 (t, 2H, NCH 2 CH 2 CH 2 ), 3.98 (t, 2H, CH 2 CH 2 CH 2 O), 2.28 (q, 2H, CH 2 CH 2 CH 2 ). 3-[6′-(4″′-Cyno-phenyl)bromo-2′-naphthoxy]-propyl-amine, (u) A solution containing compound (t) (2.0 g, 0.463 mmol) and H 2 NNH 2 . H 2 O (1.5 g, 30 mmol) in 20 ml ethanol and 80 ml chloroform was refluxed for 24 hours. Upon evaporation to dryness, the solid residue was stirred with 1 M HCl (50 ml). Then 10% NaOH (50 ml) was added to the solid collected by filtration. The resulting solution was extracted with methylene chloride (50 ml×3). The combined organic portion was dried over anhydrous MgSO 4 , and the solvent was evaporated off to yield (u) (0.8 g, 59%). Proton NMR spectral data (DMSO-d 6 ), δ (ppm): 8.24-7.18 (m, 10 H, aromatic H), 4.17 (t, 2H, CH 2 CH 2 CH 20 ), 2.74 (t, 2H, NCH 2 CH 2 CH 2 ), 1.80 (q, 2H, CH 2 CH 2 CH 2 ). Trans-cyclohexane-1,3,5-tricarboxylic acid, tris{N-[3-(4′-cyano-p-terphenyloxy)-1-propyl]}-amide, (XVIII) Under a nitrogen atmosphere, oxalyl chloride (1.0 ml, 11.0 mmol) was added dropwise to a suspension of trans-1,3,5-cyclohexanetricarboxylic acid (0.220 g, 1.02 mmol) in anyhydrous methylene chloride (20 ml) in the presence of a catalytic amount DMF. After stirring at room temperature for 1 hour, the reaction mixture was refluxed for 3 hours. Upon removing solvent and excess oxalyl chloride by evaporation in vacuo, THF (5 ml) was added to dissolve the solid residue. A solution of (u) (1.00 g, 3.31 mmole) in anhydrous DMF (20 ml) and anhydrous pyridine (1.0 ml) was then added dropwise via a syringe. Upon refluxing for 5 hours, the reaction mixture was poured into cold water (200 ml) and then acidified with 1M HCl. The resulting solid was further purified by silica gel column chromatography with methylene chloride:acetone (100:1) as the eluent, yielding (XVIII) (0.49 g, 49%). Proton NMR spectral data (DMSO-d 6 ), δ (ppm): 8.26-7.18 (m, 30 aromatic H plus 3H on amide), 4.10 (m, 6H, CH 2 CH 2 CH 2 O), 3.22 (m, 6H, NCH 2 CH 2 CH 2 ), 2.66-2.54 (m, 3H, cyclohexane core), 1.96 (m, 6H, CH 2 CH 2 CH 2 ), 1.91-1.41 (m, 6H, cyclohexane core). Anal. Calcd. for C 69 H 60 N 6 O 6 : C, 77.50; H, 5.66; N, 7.86. Found: C, 76.78; H, 5.51; N, 7.73%. 1-t-Butyldimethylsilyloxy-3,5-benzenedicarboxylic acid, bis[3-(4′-cyano-p-terphenyloxy)-1-propyl]ester, (v) DEAD (1.20 ml, 7.38 mmol) was added dropwise to a solution containing 1-t-butyldimethylsilyloxy-3,5-benzenedicarboxylic acid (0.85 g, 2.87 mmol), (r) (2.00 g, 6.06 mmol), and triphenylphosphine (2.00 g, 7.63 mmol) in 250 ml anhydrous THF. Upon stirring overnight at room temperature, the reaction mixture was poured into 400 ml methanol after reducing the volume to 50 ml. The precipitated crude product collected by filtration was dissolved in 200 ml chloroform. The resulting solution was washed with 10% NaHCO 3 (300 ml×2) and water (300 ml×2) consecutively before drying over anhydrous MgSO 4 . Further purification was accomplished by silica gel column chromatography with methylene chloride as the eluent, yielding (v) (2.3 g, 87%). Proton NMR spectral data (CD 3 Cl), δ (ppm): 8.32-7.00 (m, 27H, aromatic H), 4.59 (t, 4H, COOCH 2 CH 2 ), 4.20 (t, 4H, CH 2 CH 2 O), 2.32 (q, 4H, CH 2 CH 2 CH 2 ), 1.02 (s, 9H, SiC(CH 3 ) 3 , 0.25 (s, 6H, Si(CH 3 ) 2 . Anal. Calc. for C 58 H 54 N 2 O 7 Si 1 : C, 75.79; H, 5.92; N, 3.05. Found: C, 75.58; H, 5.93; N, 3.04%. 1-Hydroxy-3,5-benzenedicarboxylic acid, bis[3-(4′-cyano-p-terphenyloxy)-1-propyl]ester, (w) To a solution of 1.00 g (v) in 500 ml chloroform was added dropwise TBAF (1M in THF, 4 ml). After stirring for 4 hours at room temperature, HCl (1M, 2 ml) and THF (8 ml) were added. The reaction mixture was then washed twice with water. The organic layer was reduced in volume to 10 ml, from which the white solid precipitated, yielding (w) (0.74 g, 94%). Proton NMR spectral data (DMSO-d 6 ), δ (ppm): 10.32 (s, 1H, phenol H), 8.00-7.03 (m, 27H, Aromatic H), 4.47 (t, 4 H, COOCH 2 CH 2 ), 4.17 (t, 4H, CH 2 CH 2 O), 2.20(q, 6H, CH 2 CH 2 CH 2 ). 1-[3-(4′-Cyano-p-terphenyloxy)-1-propxy]-3,5-benzenedicarboxylic acid, bis [3-(4′-cyano-p-terphenyloxy)-1-propyl]ester, (XV) DEAD (0.14 ml, 0.90 mmol) was added dropwise to a solution of (w) (500 mg, 0.620 mmol) (r) (230 mg, 0.697 mmol), and triphenylphosphine (240 mg, 0.916 mmol) in 30 ml anhydrous THF and 30 ml anhydrous DMF. Upon stirring overnight at room temperature, the reaction mixture was poured into 200 ml methanol, affording a white precipitate, which was collected by filtration and then dissolved in 200 ml methylene chloride. The resulting solution was washed with 10% NaHCO 3 (200 ml×2) and water (200 ml×2) consecutively before drying over anhydrous MgSO 4 . Further purification by silica gel column chromatography, with methylene chloride:acetone (50:1) as the eluent, yielded (XV) (350 mg, 51%). Proton NMR spectral data (CDCl 3 ), δ (ppm): 8.32-7.01 (m, 39H, Aromatic U), 4.60 (t, 4H, COOCH 2 CH 2 ), 4.25 (m, 8H, OCH 2 CH 2 CH 2 O, COOCH 2 CH 2 CH 2 O, overlap), 2.33 (6H, CH 2 CH 2 CH 2 ). Anal. Calcd. for C 74 H 57 N 3 O 8 : C, 79.62; H, 5.15; N, 3.77. Found: C, 79.12; H, 5.28; N, 3.64%. The synthesis and purification procedures for (XV) were followed for (XVI), (XVII), and (XIX). 1-[2′-(3″β-5″-Cholestenyloxy)-ethoxy]-3,5-benzenedicarboxylic acid, bis [3-(4′-cyano-p-terphenyloxy)-1-propyl]ester (XVI) Yield 10%. Anal. Calcd. for C 81 H 88 N 2 O 8 : C, 79.90; H, 7.29; N, 2.30. Found: C, 79.71; H, 6.93; N, 2.48%. Proton NMR spectral data (CDCl 3 ), δ (PPM): 8.32-7.01 (m, 27H, Aromatic H), 5.37 (n, 1H, olefinic H on cholesteryl), 4.59 (t, 4H, COOCH 2 CH 2 ), 4.20 (m, 6H, CH 2 CH 2 CH 2 O, OCH 2 CH 2 O), 3.87 (2H, OCH 2 CH 2 O), 3.26 (1H, OCH 2 CH 2 OCH(on cholesteryl group)), 2.33(q, 4H, CH 2 CH 2 CH 2 ), 2.35-0.69 (m, 43H, other cholesteryl H). Anal. Calcd. for C 81 H 88 N 2 O 8 : C, 79.90; H, 7.29; N, 2.30. Found: C, 79.71; H, 6.93; N, 2.48%. 1-(2′-[4″ (3′″β-5′″-Cholestenyloxycarboxy)phenoxy]-ethoxy)-3,5-benzenedicarboxylic acid, bis [3-(4′-cyano-p-terphenyloxy)-1-propyl]ester, (XVII) Yield 33%. Proton NMR spectral data (CDCl 3 ), δ (ppm): 8.35-6.96 (m, 31H, aromatic H), 5.43 (m, 1H, olefinic H on cholesteryl moiety), 4.82 (1H, COOCH(on cholesteryl group)), 4.60 (t, 4 H, COOCH 2 CH 2 ), 4.42 (4H, OCH 2 CH 2 O), 4.20 (m, 4H, CH 2 CH 2 CH 2 O), 2.33 (q, 4H, CH 2 CH 2 CH 2 ), 2.47-0.71 (m, 43H, other cholesteryl H). Anal. Calcd. for C 88 H 92 N 2 O 10 : C, 79.01; H, 6.93; N, 2.09. Found: C, 78.64; H, 6.75; N, 2.22%. 1-{(S)-(−)-2′-(4″-[4′″-(1″″-Phenyl-ethylcarbamoyl)phenoxycarbonyl]phenoxy}ethoxy)-3,5-benzenedicarboxylic acid, bis [3-(4′-cyano-p-terphenyloxy)-1-propyl]ester, (XIX) Yield 28%. Proton NMR spectral data (CDCl 3 ), δ (ppm): 8.36-6.35 (m, 40H, aromatic H), 6.35 (d, 1H, NH), 5.37 (q, 1H, C*H(CH 3 )), 4.61 (t, 4H, COOCH 2 CH 2 ), 4.44 (s, 4H, OCH 2 CH 2 O), 4.20 (t, 4H, CH 2 CH 2 O), 2.31(q, 4H, CH 2 CH 2 CH 2 ), 1.64 (d, 3H, CHCH 3 ). Anal. Calcd. for C 76 H 61 N 3 O 1 1: C, 76.56; H, 5.16; N, 3.53. Found: C, 76.09; H, 5.02; N, 3.64%. 1,3,5-Benzenetricarboxylic acid, bis{3,5-benzenedicarboxylic acid, bis[3-(4′-cyano-p-terphenyloxy)-1-propyl]ester}phenyl}ester, (XX) A solution of 1,3,5-benzenetricarboxylic acid chloride (52.0 mg, 0.196 mmol), (w) (500 mg, 0.620 mmol) and DMA (100 mg, 0.82 mmol) in 30 ml anhydrous DMF and 30 ml anhydrous THF was heated at 80° C. for 3 hours. The reaction mixture was then poured into 200 ml ethanol. The precipitate was dissolved in 50 ml methylene chloride and then washed with 10% NaHCO 3 (50 ml×2) and water (50 ml×2) consecutively before drying over anhydrous MgSO 4 . Further purification was accomplished by silica gel column chromatography, with methylene chloride:acetone (100:1) as the eluent, to yield (XX) (40 mg, 8%). Proton NMR spectral data (CDCl 3 ), δ (ppm): 9.25-6.99 (m, 84H, aromatic H), 4.62 (t, 12H, COOCH 2 CH 2 ), 4.19 (t, 12H, CH 2 CH 2 O), 2.32(q, 12H, CH 2 CH 2 CH 2 ). Anal. Calcd. for Cl 65 H 120 N 6 O 24 : C, 77.09; H, 4.71; N, 3.27. Found: C, 76.50; H, 4.64; N, 3.26%. Molecular Structures, Thermotropic Properties, and Morphology Chemical structures were elucidated with elemental analysis, FTIR (Nicolet 20 SXC) and proton NMR (Avance-400, Bruker, and QE-300, GE) spectroscopic techniques. Thermal transition temperatures were determined by DSC (Perkin-Elmer DSC-7) with a continuous N 2 purge at 20 mL/min. Samples were preheated to 350° C. followed by cooling at −20° C./min to −30° C. before taking the reported heating scans at 20° C./min. The reported values of T g and T c were reproducible to within ±1° C. Liquid crystal mesomorphism was characterized with a polarizing optical microscope (Leitz Orthoplan-Pol) equipped with a hot stage (FP82, Mettler) and a central processor (FP80, Mettler); the nematic and cholesteric mesomorphism were identified with the threaded textures and oily streaks, respectively. The morphology of pristine and thermally processed samples was analyzed with x-ray diffractometry (XRD). X-ray diffraction data were collected in reflection mode geometry using a Rigaku RU-300 Bragg-Brentano diffractometer equipped with a copper rotating anode, diffracted beam graphite monochromator tuned to CuKα radiation, and scintillation detector. Samples were analyzed in powder form (as received), and as films (powders heated above T c then cooled to 25° C. at a rate of −20° C./min). All XRD data collection was carried out at 25° C. Measurements of Order Parameter and Selective Reflection on GLC Films Optical elements for order parameter measurements were fabricated using optically flat, calcium fluoride substrates (1.00 in. diameter×0.04 in. thickness, Optovac) that are transparent in the infrared region. Optical elements for selective reflection measurements were fabricated using optically flat, fused silica substrates (1.00 in. diameter×⅛ in. thickness, Esco Products) that are transparent down to 200 nm. In both cases, the substrates were cleaned, spin-coated with Nylon 66, and then buffed with a velvet roller. Vitrified films were prepared by melting pristine powders between two surface-treated substrates at temperatures slightly above T c and thermally annealed at temperatures slightly below T c for 1 h before cooling at −30° C./h to room temperature. Thickness was controlled using glass fiber spacers for the 14 μm films and glass spheres for the 2 μm films. Order parameter was measured by linear dichroism using a FTIR spectrometer (Nicolet 20 SXC). Two measurements were performed with the transmission axis parallel and perpendicular to the nematic director (i.e. the buffing direction) of the sample. A UV-Vis-NIR spectrophotometer (Perkin-Elmer Lambda 9) was employed to measure light absorption (at normal incidence) and selective reflection (at 15° incidence from the surface normal) at room temperature. An aluminum mirror served as a specular reflection standard. The results were reported as % reflectivity of incident unpolarized light. In both the light absorption and the reflection measurements, Fresnel reflections from the two air-glass interfaces were accounted for using a reference cell comprising an index-matching fluid sandwiched between two surface-treated substrates. The molecular structures of the high T g GLCs depicted in FIGS. 1A-C were elucidated with elemental analysis and proton NMR spectral data in CDCl 3 . Structure (I) of FIG. 1A is described in U.S. Pat. No. 5,514,296 and used herein for purposes of comparison to show improvement in the T g for the GLCs of the present invention. The equatorial configuration on the cis,cis-cyclohexane ring in (I) and (II) was determined on the basis of NMR signals in the region between δ1.50 and 3.00. The exo,exo-configuration on the bicyclo[2.2.2]oct-7-ene ring in (III) and (IV) was validated with signals near δ3.10 and 3.40 attributed to the tertiary (endo-) and bridgehead protons, respectively. Note the two triplets at δ4.35 and 4.16, attributable to the trimethylene spacer in (I), emerge as a multiplet at δ4.21 and a triplet at δ4.04 in (III), presumably because of the hindered rotation by the N 1 pendants constrained on an exo,exo-bicyclooctene ring. The singlet at δ3.11 attributable to the tertiary protons in (III) with an exo,exo-configuration is split into two multiplets at δ3.02 (exo protons) and δ3.28 (endo protons) with equal intensities in the exo,endo-configuration of (V). The signal attributable to the bridgehead proton was found to undergo a downfield shift to δ3.57 in (V) from δ3.39 in (III). It appears that the nematic pendants on the exo,endo-bicyclooctene ring in (V) are subject to hindered rotation, as in the exo,exo-configuration of (III). In addition, the endo- and exo-oriented, trimethylene spacer yielded distinct signals. Therefore, the two multiplets at δ2.09 and 4.21 plus the triplet at δ4.04 in (III) split into two sets of multiplets (2.05, 2.15) and (4.23, 4.35) plus one set of triplets (4.00, 4.07) in (V). In each set the higher field signal is attributed to the exo-configuration, and the lower to the endo-configuration in the exo, endo-bicyclooctene ring (cf. Shi and Chen, Liquid Crystals, 1995, 19, 849). The signals associated with the trimethylene spacer in (VI) are similar to those found in (V) except for the partial overlap of signals from the endo- and exo-configuration. In the case of benzene core, free rotation of both the N 1 and N 2 seems to prevail based on the NMR signals attributable to the trimethylene spacer in (VII) and (VIII), the two triplets near a δ4.70 and 4.26. For a consistent evaluation of thermal transition temperatures by DSC, all pristine samples were heated beyond the clearing temperature, T c and then cooled at −20° C./min to −30° C. before taking a heating scan at 20° C./min. The resultant thermograms were used to determine T g and T c with the nematic and chiral-nematic (i.e. cholesteric) mesophase identified by threaded textures and oily streaks, respectively, under polarizing optical microscopy. The nematic GLCs, (I) through (VIII) except (II), were further characterized by linear dichroism associated with the C≡N bond stretching at 2225 cm −1 , as shown in FIG. 2, where absorbances parallel (A ∥ ) and perpendicular (A ⊥ ) to the nematic director are shown. With the dichroic ratio, R=A ∥ /A ⊥ , the orientational order parameter can be determined, S=(R−1)/(R+2), assuming that the absorption transition moment is parallel to the nematic director. As a co-product from the statistical reaction conducted for Compound (III), (IV) was obtained as a chiral-nematic GLC with a T g of 93° C. and a T c of 127° C., representing an elevation in T g by 10 to 20° C. over all the chiral-nematics reported previously (cf. Katsis et al., Chem. Mater., 1999, 11, 1590; Shi and Chen, Liquid Crystals, 1995, 19, 849. Specifically, there are 3 nematic and 1 chiral pendants in Compound (IV), as opposed to 2 nematic and 1 chiral pendants in the cyclohexane-based chiral-nematic GLCs. It is noted that replacing one of the nematic pendants in (III) with a nonmesogenic, chiral pendant produces a chiral-nematic GLC with a somewhat elevated T g but a much depressed T c Compound (IV was melt-processed into a 2 μm thick GLC film, labeled as (A) in FIG. 3, yielding a selective reflection band around 375 nm. With an aluminum mirror serving as a specular reflector for incident unpolarized light, a perfect chiral-nematic film would yield a reflectivity of 50%. Since selective reflection appears in the UV-region, it is important to assess the extent to which light absorption distorts selective reflection. Since the chiral pendant absorbs light at a shorter wavelength than the nematic pendant, UV-absorption was measured for Compound (III) in methylene chloride at 10 −5 M. The result is presented as (D) in FIG. 3 in terms of extinction coefficient, indicating that part of the selective reflection band of the film prepared with (IV) is indeed lost to the absorption of incident light in the reflection measurement. The selective reflection spectra of 2 μm thick GLC films prepared with mixtures at molar ratios (IV):(III)=78:21 and 49:51 are presented as (B) and (C), respectively, in FIG. 3 . As expected the selective reflection band undergoes a bathochromic shift at a decreasing chiral content. Film (B) was further used to demonstrate that (S)-(−)-1-phenylethylamine gives rise to a left-handed chiral-nematic film based on the handedness of reflected incident light (cf. Chen et al., Polymer Preprints, 1999, 40(2), 117). Finally, the morphology of pristine samples and that of thermally processed GLCs were characterized by x-ray diffractometry at room temperature. As illustrated in FIG. 4, the pristine powders of (VIII) are noncrystalline. Moreover, heating pristine samples to beyond T c with subsequent thermal annealing at temperatures slightly below T c for up to 1 h before cooling to room temperature produced nematic GLCs that remain noncrystalline when left at room temperature for 6 months as illustrated with Compound (VIII) in FIG. 4 . The Glass-forming Liquid Crystals (GLCs) with elevated T g were implemented by increasing the volume of the nonmesogenic central core with an attendant increase in the number of mesogenic pendants per GLC molecule, the new GLCs possessing a T g above 100° C. with the following key observations: (i) An extended central core accompanied by an increased number of nematic pendants over the benzene, cis,cis-cyclohexane, and exo,endo-bicyclo[2.2.2]oct-7-ene base structures was found to elevate T g by 30 to 40° C. without a definite trend in T c . (ii) The exo,endo-bicyclo[2.2.2]oct-7-ene central core was prepared via modification of the exo,exo-configuration with its stereochemistry validated by proton-NMR spectroscopy. With the same nematic pendant, the exo,exo-GLC showed an elevation in T g by 13° C. and in T c by 49° C. over the exo,endo-counterpart. (iii) A left-handed chiral-nematic GLC emerged from (S)-(−)-1-phenylethylamine as the chiral moiety. Selective reflection bands ranging from the UV—to the visible spectral region were demonstrated with GLC films at a decreasing chiral content. (iv) Heating pristine samples to beyond T c followed by thermal annealing at temperatures slightly below T c and then cooling to room temperature produced well-aligned nematic GLC films as quantified by orientational order parameter measured with FTIR linear dichroism. (v) The x-ray diffraction patterns revealed the noncrystalline morphology of all pristine samples. Thermally processed GLC samples were found to remain noncrystalline when left at room temperature for 6 months. TABLE 1 Thermotropic properties of glass-forming liquid crystals †, ‡ GLC Phase Transition Temperatures I G 68° C. N 195° C. I II G 108° C. N 197° C. I III G 84° C. N 222° C. I IV G 93° C. Ch 127° C. I V G 71° C. N 173° C. I VI G 102° C. 187° C. I VII G 75° C. N 235° C. I VIII G 106° C. N 183° C. I IX G 123° C. N 154° C. I X G 120° C. N 143° C. I XI G 93° C. N 182° C. I XII G 111° C. N 184° C. I XIII G 86° C. N 288° C. I XIV G 76° C. N 153° C. I XV G 82° C. N 347° C. I XVI G 63° C. Ch 256° C. I XVII G 73° C. Ch 309° C. I XVIII G 101° C. N 197° C. I XIX G 83° C., 142° C. K 1 172° C., 175° C. K 2 189° C. Ch 223° C. I § I 219° C. Ch 77° C. G (from cooling scan) XX G 127° C. N 308° C. I † Symbols: G, glassy; N, nematic; Ch, cholesteric; K, crystalline. I, isotropic. ‡ Phase transition temperatures determined with heating scans at 20° C./min gathered with a # differential scanning calorimeter (DSC-7, Perkin-Elmer). The samples were pretreated by heating # to beyond their clearing points followed by cooling at −20° C./min. § Compound (XIX) showed crystallization upon heating, but was found to undergo glass transition upon # cooling at −20° C./min without encountering crystallization. In fact, none of the compounds listed above # showed crystallization upon cooling, indicating feasibility of preparing glassy liquid crystalline films via melt # processing into optical devices.

A glass-forming liquid crystal composition comprises a compound having a molecular weight in the range of about 1000 to 5000 grams per mole and having the formula (NEM) x —CYC—(CHI) y wherein CYC is a substituted cycloaliphatic core moiety containing about 24 to about 60 carbon atoms or a substituted aromatic core moiety containing about 6 to about 36 carbon atoms, NEM is a nematogenic pendant moiety, CHI is a chiral pendant moiety, x is 3 to 9, and y is 0 to 4. An optical device is formed from the liquid crystal composition.

TECHNICAL HELD [0001] The following disclosure relates generally to the fields of medical imaging and radiation therapy and, more specifically, to the application of image processing techniques in a computer software tool for creating a synthetic electron density information from a magnetic resonance image (MRI), e.g. for use in radiation treatment planning for cancer. BACKGROUND [0002] Tomography refers to a technique for capturing a two-dimensional (2D) or three-dimensional (3D) cross-sectional image of an object, through the use of radiation or any kind of penetrating wave. Computed Tomography (CT) refers to a medical imaging technique that uses X-rays and computer processors to collect and display 2D or 3D images or tomograms of an object. Magnetic Resonance imaging (MRI) refers to a tomographic technique that uses a powerful magnetic field and a radio frequency transmitter to capture detailed images of organs and structures inside the body. [0003] Radiation therapy refers to a technique where cancer tumors are controlled or killed by the application of high energy ionizing radiation. In the case of external radiation therapy the ionizing radiation is applied from outside the body from one or more directions, which are all directed towards the tumor to be treated. The ionizing radiation is often generated by a linear electron accelerator. The uptake of radiation by a tissue volume is referred to as the dose given to the tissue. A complete cancer treatment usually consists of several radiation therapy sessions, each of which is referred to as a fraction. [0004] Radiation treatment planning refers to the step preceding the radiotherapy sessions, during which the application of radiation is carefully planned. Different organs and tissues exhibit different sensitivity to radiation. Organs and tissue for which the radiation will cause most negative side effects are referred to as risk organs. The area containing the tumor to be treated is referred to as the target. During radiation treatment planning the goal is to provide a specific dose to the target, while keeping it as low as possible to the surrounding risk organs. The means available for this are the angles from which the radiation is applied, together with the shape and strength of the radiation beam. In order to achieve this, the radiation treatment planning step is typically preceded by a tomographic step, which is then used for the identification and localization of target and risk organs. [0005] Attenuation refers to the gradual loss of energy as a signal passes through a medium. In the context of CT, attenuation of the X-ray energy occurs as the X-rays pass through different tissues and structures in the body. The grayscale values in the CT image constitute an accurate representation of this attenuation at each location. Different tissues have different properties and densities and, thus, produce different amounts of attenuation. The attenuation coefficient describes the extent to which a particular material or tissue causes a loss of energy. In the context of radiotherapy, attenuation occurs as the radiation passes through the body and dose is absorbed by different tissues and structures. [0006] In order to be able to accurately calculate the dose given to both target and risk organs, it is of high importance to know the exact energy deposition at every location through which the radiation passes. For this reason the tomography preceding the radiation treatment planning is traditionally CT, since there is a relation between the CT values and the dose deposition of the high-energy radiation used for radiotherapy. [0007] Since a CT image constitutes a representation of X-ray attenuation, the primary contrasts within a CT image is that between bone, soft-tissue and air. Both between and within different types of soft-tissues (such as organs, muscles and fat), the image contrast is highly limited. During radiation treatment planning, this low contrast is a disadvantage, since it limits the accuracy by which target and risk organs can be identified. [0008] Traditionally, radiation therapy planning specialists must often estimate and guess at the target and risk organ size and location based on their experience. Bony structures, or marker implants, provide the primary reference landmarks within the image. For this reason, the usual practice during planning is to “overstate” the area within the patient for subsequent radiation treatment. Thus, the radiation beam will be sure to hit the intended target. However, the disadvantage is that otherwise healthy tissue is thereby also unnecessarily irradiated. [0009] For this reason, modern radiotherapy often also includes an additional MRI scan which is also performed prior to the radiation treatment planning, which has superior contrast between different soft tissues compared to the CT image. Such MRI scan is typically aligned to the CT scan and used in conjunction with the CT during the radiation treatment planning. [0010] However, even such combined CT/MRI workflow has several disadvantages. First, acquiring both an MRI and a CT is both expensive and time consuming, and it also adds additional discomfort to the patient. Secondly, the registration between MRI and CT is rarely perfect, which adds an uncertainty to the identification of both the target and the risk organs. In addition, the CT itself adds a significant radiation dose to the patient, which limits its repeated use in following tumor changes between fractions. [0011] Therefore, a solution which would enable an MRI-only workflow, and thereby eliminate the requirement of CT, in radiation treatment planning, is highly sought for. [0012] US 2011/0007959 discloses a method, wherein co-registered CT and MRI anatomical structure reference images are used. When an MR image of a patient is acquired, a user can click and drag landmarks on the reference MR image to deform the reference MR image to align with the patient MR image. The registration of landmarks also registers the patient MR image with a corresponding landmark in the co-registered reference CT image. However, this method requires extensive user interaction in order to generate desired electron density information. [0013] In Hofmann et al, “MRI-Based Attenuation Correction for PET/MRI: A Novel Approach Combining Pattern Recognition and Atlas Registration”, Journal of Nuclear Medicine, 2008, volume 49, issue 11, pages 1875-1883, a method for using MRI in creation of synthetic CT, or attenuation correction information, which accounts for radiation-attenuation properties of the tissue. The method uses a non-rigid registration algorithm for aligning a template MR image with a new subject's MR image. This alignment is then used to compute a desired result from a template CT image. SUMMARY OF THE INVENTION [0014] With the above description in mind, then, an aspect of some embodiments of the present invention is to provide a method for generating synthetic CT image stacks for use in radiation treatment planning, which seeks to mitigate, alleviate or eliminate one or more of the above-identified deficiencies in the art and disadvantages singly or in any combination. [0015] According to a first aspect of the invention, there is provided a method for generating synthetic electron density information based on an acquired magnetic resonance, MR, image stack, said method comprising: analyzing the acquired MR image stack in order to automatically segment the acquired MR image stack such that structure information defining locations and/or geometry of structures in the acquired MR image stack is determined; generating warp information for a template dataset, said template dataset comprising at least one template electron density information map and at least one template structure information, said generating comprising utilizing said structure information and said template structure information representing locations and/or geometry of template structures in order to determine transformations bringing the template structures in spatial correspondence with the structures in the acquired MR image stack, wherein said generated warp information describes at least one transformation bringing the at least one template electron density information map in spatial correspondence with the acquired MR image stack; and forming synthetic electron density information corresponding to the acquired MR image stack based on at least part of the at least one template electron density information map, wherein the at least part of the at least one template electron density information map is warped using the generated warp information. [0016] According to the method, segmentations defining information about structures in image stacks are used for relating a template to the acquired MR image stack. Hereby, the locations and/or geometry of structures drive the determination of transformations that would bring the template structures in spatial correspondence with the structures in the acquired MR image stack. This implies that it is not necessary to use a template MR image stack which is to be first registered to the acquired MR image stack, before the relation of the template electron density information map to the acquired MR image stack may be determined. [0017] Using the segmentation for generating the warp information also enables bringing template electron density information maps into spatial correspondence with the currently acquired MR image stack, even though the template electron density information maps and the currently acquired MR image stack may be acquired from different persons with highly different geometries. Thanks to the segmentation, the template electron density information maps may still be accurately related to the acquired MR image stack and may thus provide valuable information for forming the synthetic electron density information. [0018] According to a second aspect of the invention, there is provided a system for generating synthetic electron density information based on an acquired magnetic resonance, MR, image stack, said system comprising: an automatic segmentation module, which is configured to analyze the acquired MR image stack such that structure information defining locations and/or geometry of structures in the acquired MR image stack is determined; a warp module, which is configured to generate warp information for a template dataset, said template dataset comprising at least one template electron density information map and at least one template structure information, said generating comprising utilizing said structure information and said template structure information representing locations and/or geometry of template structures in order to determine transformations bringing the template structures in spatial correspondence with the structures in the acquired MR image stack, wherein said generated warp information describes at least one transformation bringing the at least one template electron density information map in spatial correspondence with the acquired MR image stack; and a forming module, which is configured to form synthetic electron density information corresponding to the acquired MR image stack based on at least part of the at least one template electron density information map, wherein the at least part of the at least one template electron density information map is warped using the generated warp information. [0019] Thus, a system facilitating generation of synthetic electron density information is provided. The system may be set up in a remote location, such that when an MR image stack is acquired at a hospital, the MR image stack may be received by the system and synthetic electron density information may be returned. This implies that hospitals may benefit from a large number of gathered templates, which may be continuously improved and provided with further templates, and the individual hospitals need not gather their own templates. [0020] However, it should be realized, that the system may also be set up locally, e.g. within a hospital. This may provide simpler handling of information as less restrictive data encryption and patient de-identification strategies may be allowed, as compared to information being transmitted to a system outside the hospital. [0021] As used herein, the term “electron density information” should be construed as information that enables calculation of the absorbed radiation dose in an object. For instance, this could be a CT image stack, which constitutes a representation of Hounsfield values. However, when radiotherapy is applied, high-energy photon, proton or electron radiation is typically used and the information provided by the CT image stack may need to be transformed in order to give the absorbed radiation dose. Thus, the electron density information may alternatively be information more directly describing properties relevant to radiation used in radiotherapy, and the term “electron density information” should thus be construed to include such information. For certain types of radiation treatment, e.g. protons, this information may be in the form of stopping power maps, which also falls within the meaning of the term “electron density information” as used herein. [0022] According to one embodiment, the synthetic electron density information is in the form of a synthetic CT image stack and the at least one template electron density information map is a template CT image stack. [0023] As used herein, the term “image stack” should be construed as any representation of image information that collectively represents three-dimensional information of an imaged object. [0024] It should be realized that the template structure information need not necessarily be transformed to be brought in spatial correspondence with the structures in the acquired MR image stack. In particular, it is not necessary to transform the template electron density map. It may be sufficient to determine the transformation that would bring the template electron density map to such spatial correspondence. Such determination forms information about the relation between the template structure and the acquired MR image stack, which information may be used as input to how synthetic electron density information is to be formed from the at least one template electron density information map. [0025] Further, the template electron density information maps need not necessarily be warped using the warp information. Rather, a decision on which parts of a template electron density information map that is to be part of forming the synthetic electron density information may be taken, and then these parts may be warped when the synthetic electron density information is formed. [0026] The synthetic electron density information may be formed based on a single template electron density information map. This may be especially useful e.g. when the template electron density information map is based on the same patient as the acquired MR image stack. [0027] According to an embodiment, a set of template electron density maps are used and said generated warp information describes transformations bringing each template electron density information map in the set of template electron density information maps in spatial correspondence with the acquired MR image stack, wherein said forming comprises fusioning at least parts of the template electron density information maps, wherein the at least parts of the template electron density information maps are warped using the warp information, to form synthetic electron density information corresponding to the acquired MR image stack. [0028] This implies that a plurality of template electron density maps may be used for contributing to the synthetic electron density information. Also when using a plurality of template electron density maps, the template electron density information maps need not be warped before fusioning. Rather, only the parts that are to be fused may be warped. [0029] It should be realized that a plurality of template electron density maps may be included in the template dataset, whereas the set of template electron density maps used may be a subset of the plurality of template electron density maps. The template structure information may be provided in several different ways and may accordingly be related to the template electron density information maps in different ways. [0030] In one embodiment, the template electron density information maps may be previously segmented in order to comprise template structure information providing locations and/or geometry of template structures within the template electron density information map. In such case, the determined transformation(s) bringing the template structures in spatial correspondence with the structures in the acquired MR image stack may be equal to transformation(s) that would bring the template electron density information map in spatial correspondence with the acquired MR image stack. [0031] In another embodiment, separate template structure information is provided, which represents the locations and/or geometry of template structures. The template structure information may be related to the template electron density information map to describe how the template structures according to the template structure information correspond to the template electron density information map. Thus, the determined transformation(s) bringing the template structures in spatial correspondence with the structures in the acquired MR image stack may then contribute to determining warp information that describes at least one transformation bringing the at least one template electron density information map in spatial correspondence with the acquired MR image stack. [0032] In another embodiment, the template dataset further comprises at least one template MR image stack and said generating of warp information comprises determining spatial deformations of the at least one template MR image stack, said spatial deformations bringing the at least one template MR image stack in spatial correspondence with the acquired MR image stack, wherein the at least one template MR image stack has been segmented to identify template structure information representing locations and/or geometry of structures in the at least one template MR image stack, said spatial deformations comprising utilizing the structure information of the acquired MR image stack and the template structure information in order to bring the structures of the at least one template MR image stack to spatial correspondence with corresponding structures of the acquired MR image stack; and wherein the at least one template electron density information map is associated to respective ones of the at least one template MR image stack to define spatial and geometric relation between the at least one template MR image stack and the at least one template electron density information map, said generated warp information being based on the determined spatial deformation and said spatial and geometric relation. [0033] Hence, template MR image stacks may be used, which are provided or related to template structure information. This implies that a spatial deformation may first be determined based on bringing the template structure information related to the template MR image stack in spatial correspondence with corresponding structures of the acquired MR image stack. Then, the warp information may be generated based on a further spatial and geometric relation between the template electron density information map and the template MR image stack. [0034] The template MR image stacks need not be actually deformed to bring the template structure information related to the template MR image stack in spatial correspondence with corresponding structures of the acquired MR image stack. However, in one embodiment, the template MR image stack is spatially deformed in order to bring the template MR image stack in spatial correspondence with the acquired MR image stack. Thus, the determining of spatial deformations may actually include deforming the template MR image stacks. [0035] In one embodiment, generating warp information comprises warping the template electron density information maps. This warping may generate candidate electron density information maps, which may then be used in fusioning for forming the synthetic electron density information maps. [0036] The template electron density information maps may be associated to the template MR image stacks to provide a relation between a template electron density information map and its respective template MR image stack. In this regard, the template electron density information map may be registered to the template MR image stack. However, it should be realized that, instead of ensuring that the template electron density information map is registered to the template MR image stack, information defining the relation between the electron density information map and its respective template MR image stack may be provided. In such case, the warp information may be partly based on the relation between the template electron density information map and its respective template MR image stack in order to calculate how the template electron density information map relates to the acquired MR image stack. [0037] In one embodiment, the template electron density information maps and the template MR image stacks are associated in pairs. The pairs may have been acquired from the same person. However, it should be realized that two or more template electron density information maps may be related to the same template MR image stack, or vice versa. [0038] As used herein, the term “spatial correspondence” should be construed as the template structures represented by the template structure information and the acquired MR image stack being arranged so that like structures are either similarly placed or both similarly placed and similarly shaped. The template structures and the acquired MR image stack may thus be arranged to share a common coordinate system. The “spatial correspondence” may, at least in some embodiments, also imply that patterns or visual features in a template image (template electron density map or template MR image stack) are matched to patterns in the acquired MR image stack and brought in correlation where a high overlap is achieved between the patterns. Further, the term “spatial correspondence” should not be construed as template structures necessarily being in exact alignment with the acquired MR image stack. In fact, parts of the template structures may not be exactly matched with the acquired MR image stack, in particular, if a template MR image stack and the acquired MR image stack are acquired from different persons. [0039] The warp information may comprise non-rigid transformation of the at least one template electron density information map. Such transformation allows the template electron density information map to be e.g. plastically or elastically deformed to achieve a high spatial correspondence between the template electron density information map and the acquired MR image stack. [0040] The fusioning of at least parts of the template electron density information maps may use different parts from different template electron density information maps, on which the warp information has been applied, in order to stitch these warped parts together to form synthetic electron density information. In an embodiment, the fusioning may use as small parts as single pixels from the template electron density information maps. However, the fusioning may alternatively use partly or completely overlapping parts of the template electron density information maps in order to combine the information from one or more template electron density information maps into a part of the synthetic electron density information. Further, the fusioning may use entire template electron maps. [0041] In one embodiment, fusioning may comprise, for each voxel location in the synthetic electron density information map to be formed, calculating a median value for each warped template electron density information map. [0042] In another embodiment, fusioning may comprise utilizing expectation maximization algorithms to estimate a most likely value at each voxel location in the synthetic electron density information map. [0043] In another embodiment, fusioning may comprise using a local image similarity metric, providing a measure of a correspondence between a spatially deformed template MR image stack and the acquired MR image stack. In such case, the fusioning may comprise, for each voxel location in the synthetic electron density information map to be formed, selecting a value from the warped template electron density information map corresponding to the spatially deformed template MR image stack having the highest similarity to the acquired MR image stack according to the local image similarity metric. [0044] According to one embodiment, the analyzing of the acquired MR image stack is made in order to identify locations and/or geometry of at least one of or a part of: bone and skeleton parts, fat, muscle tissue, inner organs, intestines, bowels, colon, bladder, reproductive organs, brain regions, eyes, cochlea, sinuses, spine, mouth, nerves, glands, blood vessels, lungs, airways, heart, tumours or metastases. It should however be realized that any part or structure of a body may be identified in the acquired MR image and that the above is not an exclusionary list. According to one embodiment, the analyzing of the acquired MR image stack is made in order to identify locations and/or geometry of any type of markers, implants or prostheses (e.g. hip prosthesis, gold markers). According to yet another embodiment, the analyzing of the acquired MR image stack is made in order to identify locations and/or geometry of any type of resection cavity or other effect from previous treatments or traumas. [0045] According to one embodiment, the analyzing of the acquired MR image stack may comprise a template-based method for automatically segmenting the acquired MR image stack. [0046] According to one embodiment, utilizing the information of locations and/or geometry of structures in the acquired MR image stack and the template MR image stacks comprises performing non-rigid form transformation between locations and/or geometry of structures in the acquired MR image stack and the template MR image stacks. [0047] According to one embodiment, the generated warp information comprises deformation fields utilized in the transformations bringing the at least one template electron density information map in spatial correspondence with the acquired MR image stack. [0048] The deformation fields need not provide information describing transformations of each part of the template electron density information map. The generated warp information may also include transformation matrices describing transformations of one or several parts of the template electron density information map. Between parts for which any such transformation is described, interpolation may be applied. [0049] According to an embodiment, the system further comprises a database in which the at least one template density information map and the at least one template structure information are stored. [0050] According to an embodiment, the method further comprises accessing a database in which template data is stored, and selecting a set of data from the database to constitute the template dataset. [0051] The set of template data that is selected from the database may be a sub-set of all template data that is stored in the database. The set of template data may thus be selected such that relevant template electron density information maps may be retrieved. According to one embodiment, the selected set of template electron density information maps forms a representative population of a region that is imaged in the acquired MR image stack. [0052] According to one embodiment, the template data is stored in the database in association with information about a person, and the selection of the data to constitute the template dataset is based on a combination of information including: gender, age, weight, ethnicity, body mass index (BMI), pathology, or other parameters. [0053] According to one embodiment, the template MR image stacks and associated template electron density information maps are arranged in close geometric registration to each other. The template MR image stacks and associated template electron density information maps may be thoroughly analyzed in order to bring them in close geometric registration to each other. The analysis may be manually, semi-automatically or automatically performed. [0054] As used herein, the term “template MR image stack” should be construed as an image stack comprising MR information, but which does not necessarily have to be directly acquired from an MRI scanner. The template MR image stack may be a synthetic image stack that is generated by combining and/or improving one or more MR image stacks. For instance, each template MR image stack may be an average image stack based on a plurality of acquired MR image stacks. [0055] Further, it should be realized that any data in a template dataset may be arranged in a common data structure and need not form separate data structures. Thus, a data structure in the form of a vector comprising a plurality of the data in the template dataset may form the template dataset. [0056] According to one embodiment, the determining of said spatial deformations further comprises, after said utilizing, improving the spatial correspondence of the template MR image stacks with the acquired MR image stack by applying non-rigid image registration between the at least one template MR image stack and the acquired MR image stack. This implies that the determining of spatial deformations may comprise both using segmentation of structures in the acquired MR image stack and the template MR image stack and using an image registration technique. Hence, a very accurate spatial correspondence between the template MR image stack and the acquired MR image stack may be determined. [0057] It should be realized that such improving of the spatial correspondence may also be performed directly between a template electron density information map and the acquired MR image stack, and need not necessarily be applied to a template MR image stack that the template electron density information map is associated with. [0058] According to a third aspect of the invention, there is provided a computer program product comprising a computer-readable medium with computer-readable instructions such that when executed on a processing unit the computer program product will cause the processing unit to perform the method according to the first aspect of the invention. [0059] According to a fourth aspect of the invention, there is provided a data structure comprising synthetic electron density information which is obtained by the method according to the first aspect of the invention. [0060] According to a separate aspect of the invention, which need not be combined with other features previously described, such as automatic segmentation, there is provided a method for generating synthetic electron density information based on an acquired magnetic resonance, MR, image stack, said method comprising: determining spatial deformations of a set of template MR image stacks, said spatial deformations bringing each of the template MR image stacks in spatial correspondence with the acquired MR image stack, wherein said determining of spatial deformations generates warp information, wherein the warp information describes transformations bringing each template MR image stack in spatial correspondence with the acquired MR image stack, applying the generated warp information to a set of template electron density information maps, wherein the template electron density information maps are associated to respective ones of the template MR image stacks to form correlations between template MR image stacks and template electron density information maps, said applying providing a description of a warping of the template electron density information maps using the warp information; and fusioning at least parts of the template electron density information maps, wherein the at least parts of the template electron density information maps are warped using the warp information, to form synthetic electron density information corresponding to the acquired MR image stack. [0061] According to this separate aspect, there is provided a set of template MR image stacks and a set of template electron density information maps that are associated to the template MR image stacks. When an MR image stack of a patient is acquired, the set of templates can thus be used for forming synthetic electron density information, whereby there is no need to acquire information that can be more directly related to the absorbed dose in the patient, such as a CT image stack. The set of template MR image stacks and the set of template electron density information maps may comprise a great amount of templates such that the acquired MR image stack can be compared to a large number of previously acquired templates in order to determine synthetic electron density information for the patient. By means of fusioning of the information from the template electron density information maps, synthetic electron density information of good quality may be obtained from the acquired MR image stack even though numerous templates or parts of the templates may not be very similar to the acquired MR image stack. [0062] For instance, the templates need not be acquired from the same patient as the acquired MR image stack. This may also imply that a patient that is to undergo radiation treatment need not be exerted to radiation doses for acquiring information for radiation therapy planning. BRIEF DESCRIPTION OF THE DRAWINGS [0063] These and other aspects of the present invention will now be described in further detail, with reference to the appended drawings showing embodiment(s) of the invention. [0064] FIG. 1 is a schematic view showing an exemplary system for generating synthetic electron density information. [0065] FIG. 2 is a schematic view illustrating an embodiment of an Automatic Segmentation Engine. [0066] FIG. 3 is a flow chart illustrating a method according to an embodiment of the invention. DETAILED DESCRIPTION [0067] Embodiments of the present invention relate, in general, to the field of generating synthetic electron density information. The forming of synthetic electron density information may be particularly useful for MRI based radiation treatment planning. However, it should be realized that it may be used in other applications as well. For instance, the synthetic electron density information may be used as attenuation information for a positron emission tomography (PET) camera or a single-photon emission computed tomography (SPECT) camera. [0068] A preferred embodiment relates to generating synthetic CT image stacks for radiation dose calculation in cancer radiotherapy, such as prostate treatments, based on one or more MRI image stacks. However, it should be appreciated that the invention is as such equally applicable to radiotherapy in any other anatomical area, such as brain, head/neck, lungs, uterus, abdomen, or any other region in which radiation treatment planning is required. Likewise, it should be appreciated that the invention is not limited to human radiotherapy only, but is equally applicable with any species for which radiation treatment planning is required. However, for the sake of clarity and simplicity, the invention is mainly described below in relation to embodiments relating to forming synthetic CT image stacks for use in human radiation therapy planning. [0069] Embodiments of the present invention will be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like reference signs refer to like elements throughout. [0070] In this context the term “registration” refers to the process of aligning a source image to a destination image, such that the source image is brought into the same coordinate system as the destination image, with as high overlap between visual features in the images as is possible. The term “rigid registration” refers to a registration process where the maximum overlap is achieved only by moving and rotating the source image relative to the destination image. The term “similitude registration” refers to a registration similar to a rigid registration, but with an additional scaling of the source image included. The term “non-rigid registration” refers to a registration process where the source image is e.g. plastically or elastically deformed to achieve the best possible overlap between the source and the destination images. The measurement by which the overlap between the images is measured is referred to as the “similarity metric”. Common similarity metrics used in image processing include cross correlation, mutual information and sum of squared difference. [0071] In this context the term “warping” refers to the process of deforming an image such that shape, size and location of structures and features within an image may be changed, Exemplary Synthetic CT System [0072] In FIG. 1 one embodiment in which the invention is used is shown. This embodiment of the synthetic CT system may typically comprise an MRI scanner 102 , a Patient Data Repository 104 , a system 106 for generating synthetic CT image stacks, to which system 106 image stacks are sent and received from the Patient Data Repository, a Radiation Treatment Planning module 108 and finally a Radiotherapy module. The system 106 to which image stacks are sent and received may comprise an Automatic Segmentation Engine 110 , an Image Warping Engine 114 , an Image Fusion Engine 116 and a Segmented Template Image Repository 118 . Each of the elements in FIG. 1 may be embodied in hardware, software or computing instructions. [0073] The Patient Data Repository 104 , in some embodiments, may be configured to store raw image data obtained from the MRI scanner 102 or from other sources, and may include other images, computing instructions, and other associated parameters such as image types, regions, weights, values and characteristics. The Patient Data Repository 104 may include any type of memory for storing images, such as a static memory, magnetic memory, random access memory, non-volatile memory, volatile memory, magnetic storage, optical storage, and the like. The Patient Data Repository 104 is optionally configured to communicate with any or all of the MRI scanner 102 , software of the Radiation Treatment Planning module 108 and a Linear Accelerator 120 implementing the Radiotherapy module. The communication may be through a direct connection, over a computing network, or through an alternative communication method. [0074] Radiation Treatment Planning includes the process of manually or automatically delineating target and risk organs on tomographic image stacks, followed by forward or inverse treatment planning, using static or dynamic radiation beams, in combination with static or modulated beam shape (using techniques such as Volumetric Modulated Arc Therapy (VMAT) and Intensity-Modulated Radiation Therapy (IMRT)). A workstation executing Radiation Treatment Planning may utilize any software, from any vendor, for radiation treatment planning (for example software such as Eclipse, Raystation, Monaco or MasterPlan). [0075] The Linear Accelerator 120 may deliver high energy photon radiation which kills tumor cells. The delivery of the radiation carefully follows the previously made dose plan, and may be accompanied by an additional imaging step to account for patient specific variation at the time of irradiation. All communications may utilize standardized file formats such as files meeting the Digital Imaging and Communications in Medicine (DICOM) standard, e.g. DICOM files and DICOM-RT files, for exchange of image stacks and other data. [0076] The system 106 for generating synthetic CT image stacks may be implemented in a computing unit, such as a server, which may be connected to a computer network for allowing communication between the system 106 and the Patient Data Repository 104 . In an embodiment, the system 106 may be implemented as an online cloud-computing platform. The system 106 may be accessible over the Internet and may utilize standardized communication means for sending data to and from the Patient Data Repository 104 . Communications may be encrypted and the communicated data may be anonymized. In order to re-identify data as it is sent from the online platform to the Patient Data Repository 104 , a client software may be running within the same network as the Patient Data Repository 104 , which holds the keys required for re-identifying data belonging to previously anonymized patients. [0077] The cloud-computing platform may further comprise software modules that generate the synthetic CT which may be used for dose calculations in radiation treatment planning. An incoming MR image stack may be received from a Patient Data Repository 104 . The incoming image stack may automatically be segmented in several anatomical regions by the Automatic Segmentation engine 110 . The incoming image stack, together with the automatically generated segments and a set of template electron density maps with previously created segments from a Segmented Template Image Repository 118 , may be processed using the Image Warping Engine 114 into a set of candidate synthetic CT image stacks. The candidate synthetic CT image stacks may then be fused using the Image Fusion Engine 116 into a final synthetic CT image stack which corresponds to the incoming MR image stack. The synthetic CT image stack may form a data structure that is returned to the Patient Data Repository 104 using the communication means previously described. Optionally, the synthetic CT image stack may be returned to one or several Patient Data Repositories, which may be other repositories than the one the incoming MR image stack was received from. In this context, a Patient Data Repository may refer to any location where medical images are saved, either permanently or temporarily, including Hospital Information System (HIS), Radiology Information System (RIS), Picture Archiving and Communication System (PACS), network drives, Radiotherapy planning databases, local hard drives, Universal Serial Bus (USB) sticks, compact disc (CD), digital versatile disc (DVD), online storage, mobile devices, etc. [0078] In another embodiment of the invention, the Automatic Segmentation Engine 110 , the Image Warping Engine 114 , the Image Fusion Engine 116 and the Segmented Template Image Repository 118 are running on a local computer or compute cluster on the same local network as, or otherwise directly connected to, the Patient Data Repository 104 . The computing may optionally be performed using central processing unit (CPU), graphics processing unit (GPU), field-programmable gate array (FPGA), application specific integrated circuit (ASIC) or any other type of computing resources implemented either in software or hardware. The Automatic Segmentation Engine 110 , the Image Warping Engine 114 , the Image Fusion Engine 116 and the Segmented Template Image Repository 118 may be executed on a common such computing resource or may be separated on one or more different computing resources. [0079] In one embodiment, a computer program product is provided for bringing a processing unit to implement the Automatic Segmentation Engine 110 , the Image Warping Engine 114 , and the Image Fusion Engine 116 . The computer program product may thus be installed on any suitable processing unit for executing the functionality of the modules. [0080] In yet another embodiment of the invention, all or any of the Automatic Segmentation Engine 110 , the Image Warping Engine 114 , the Image Fusion Engine 116 and the Segmented Template Image Repository 118 are integrated with either the MRI Scanner 102 , the Patient Data Repository 104 , the Radiation Treatment Planning module 108 , the Linear Accelerator 120 or any combination thereof. [0081] In another embodiment of the invention, the radiation for radiotherapy in the Radiotherapy module is optionally generated using a synchrotron. In yet another embodiment of the invention, the radiation for radiotherapy is generated by a radioactive isotope positioned at a number of locations outside the body. In yet another embodiment of the invention, radiation for radiotherapy is delivered using radioactive isotopes located inside the body (i.e. brachytherapy). The radiation used for radiotherapy in this invention may be of any type (i.e. photon, proton, electron, etc.). [0082] In another embodiment, the synthetic CT image stack may be generated by registering a set of template MR image stacks, which may come from the Segmented Template Image Repository 118 , to the incoming MR image stack. This may be followed by warping a corresponding set of template CT image stacks, which may come from the Segmented Template Image Repository 118 , using deformation fields generated by the previous registrations, thereby generating a set of candidate synthetic CT image stacks which may be fused to a final synthetic CT image stack using the Image Fusion Engine 116 . Each pair of template CT and template MR image stacks are first brought into alignment and may depict the same region of the same person. [0083] Details of the parts of the system 106 for generating synthetic CT image stacks will now be further described. Automatic Segmentation Engine [0084] The Automatic Segmentation Engine 110 , in some embodiments, comprises software algorithms to automatically label anatomical structures within the incoming MR image stack. Such structures may include, but is not limited to, bone and skeleton parts, fat, muscle tissue, inner organs, intestines, bowels, colon, bladder, reproductive organs, brain regions, eyes, cochlea, sinuses, spine, mouth, nerves, glands, blood vessels, lungs, airways, heart, tumours or metastases, any type of markers, implants or prostheses (e.g. hip prosthesis, gold markers), or any type of resection cavity or other effect from previous treatments or traumas. [0085] In FIG. 2 one embodiment of the Automatic Segmentation Engine 110 is shown. In order to aid automatic segmentation a number of template image stacks 122 a - c are segmented in beforehand to form segmented template image stacks 124 a - c . Each of a number of the previously segmented template image stacks 124 a - c is registered using a registration module 126 to an incoming MR image stack 128 . The template segmentations 124 a - c may be generated manually by one or several raters, or otherwise generated through other manual, semi-automatic and automatic processes. The segmented template image stacks 124 a - c may constitute a subset of the data from the Segmented Template Image Repository 118 . The registration may be performed using any combination of rigid, similitude, affine or non-rigid registration methods. Each of the registrations may generate a deformation field, which may be applied to the segmentation which corresponds to the registered template, thereby generating segmentation candidates 130 a - c representing the incoming MR image stack. All generated segmentation candidates 130 a - c may then be fused by a segment fusion module 132 to a final segmentation 134 representing the incoming MR image stack 128 . Such fusion method may be of a plurality of types, including majority voting, varieties of weighted voting, expectation maximization based label fusion etc. [0086] In other embodiments the Automatic Segmentation Engine 110 may be based on an active contour model, active shape model, active appearance model, or any other segmentation technique. In yet another embodiment the Automatic Segmentation Engine 110 may utilize neural networks or other machine learning techniques during the segmentation process. In yet another embodiment, the automatically generated results may be verified and adjusted manually. In yet another embodiment, the Automatic Segmentation Engine 110 may utilize a combination of any of the mentioned techniques during the segmentation process. The Automatic Segmentation Engine 110 may utilize all or a subset of any image stack, or any features derived thereof, during the segmentation process. Segmented Template Image Repository [0087] The Segmented Template Image Repository 118 , in some embodiments, comprises tomographic image stacks for a number of persons. For each person MR and correlated CT image stacks may be stored in the repository, which both may cover the same anatomical region and for which the CT image stack may be warped such that its structures accurately overlap that of the MRI stack to which it is correlated. The warping may be achieved using a combination of automated registration techniques, or based on manual interaction, or from a combination thereof. The warping may be represented as a transformed image stack. However, the CT image stack need not be actually warped to be in registration with the MR image stack. Rather, information regarding the spatial and geometric relation between the CT image stack and MR image stack may be stored, e.g. as a set of deformation parameters. [0088] For each person a number of anatomical structures may be segmented. Such structures may include, but is not limited to, bone and skeleton parts, fat, muscle tissue, inner organs, intestines, bowels, colon, bladder, reproductive organs, brain regions, eyes, cochlea, sinuses, spine, mouth, nerves, glands, blood vessels, lungs, airways, heart, tumours or metastases, any type of markers, implants or prostheses (e.g. hip prosthesis, gold markers), any type of resection cavity or other effect from previous treatments or traumas, etc. Such segmentations may be generated manually by one or several persons, or otherwise generated through other manual, semi-automatic and fully automatic processes. [0089] The Segmented Template Image Repository 118 need not comprise template MR image stacks. The CT image stacks may be provided with information defining locations and/or geometry of structures within the CT image stack. As a further alternative, separate template structure information, which need not be residing within a MR image stack or a CT image stack, may be provided. [0090] In one embodiment of the Segmented Template Image Repository 118 , the image stacks which are utilized are selected based on any combination of gender, age, weight, ethnicity, body mass index (BMI), pathology or any other parameter which may affect the results. [0091] In one embodiment of the Segmented Template Image Repository, the previously described warping is instead performed from the MR image stack to the CT image stack. [0092] In yet another embodiment, the image stacks in the Segmented Template Image Repository 118 are, fully or partially, synthetically generated based on features derived from images of real persons. Image Warping Engine [0093] The Image Warping Engine 114 , in some embodiments, uses any template structure information, which may be stored with the CT image stacks or may be provided as separate template structure information. The template structure information may be used for determining a relation between the locations and/or geometry of template structures and the locations and/or geometry of structures in the acquired MR image stack. This relation may then be used to generate warp information describing at least one transformation bringing the CT image stack in spatial correspondence with the acquired MR image stack. [0094] The CT image stacks and the template structure information may form a template dataset that is handled by the Image Warping Engine 114 . The template dataset may be selected from the Segmented Template Image Repository 118 . [0095] The Image Warping Engine 114 , in some embodiments, takes a set of template MR image stacks from the Segmented Template Image Repository 118 and determines spatial deformations that would bring the template MR image stacks in spatial correspondence with the incoming MR image stack. [0096] The set of template MR image stacks may be selected and included in the template dataset from the Segmented Template Image Repository 118 in order to retrieve MR image stacks that form a representative population of a region that is imaged in the acquired MR image stack. The selection may also be based on information of the persons who are imaged in the template MR image stacks, using information such as gender, age, weight, ethnicity, BMI, pathology, or any other parameter which may affect the results. [0097] The Image Warping Engine 114 may use the segmentation of the incoming MR image stack as made by the Automatic Segmentation Engine 110 . The template MR image stacks may be previously segmented. The segmentations may hold information of locations and/or geometry of structures and labels of such structures in the incoming MR image stack as well as the template MR image stacks. [0098] For each of the selected template MR image stacks, the Image Warping Engine 114 may calculate a transformation based on the locations and/or geometry of corresponding structures in the template MR image stack and the incoming MR image stack in order for the structures to be spatially corresponding. The segmentations may thus drive the transformation of the template MR image stack in order to bring the template MR image stack in spatial correspondence with the incoming MR image stack. [0099] According to one embodiment, utilizing the information of locations and/or geometry of structures in the acquired MR image stack and the template MR image stacks comprises performing non-rigid form matching between locations and/or geometry of structures in the acquired MR image stack and the template MR image stacks. [0100] The relation between the template MR image stack and the incoming MR image stack may be even further improved after the segmented structures have been used in order to align the template MR image stack and the incoming MR image stack. [0101] According to one embodiment, the improvement may comprise applying non-rigid image registration, for example matching an image similarity metric between the template MR image stack and the acquired MR image stack. This implies that the determining of spatial deformations may comprise both using segmentation of structures in the incoming MR image stack and the template MR image stack and using an image similarity metric. Hence, a very accurate spatial correspondence between the template MR image stack and the acquired MR image stack may be determined. [0102] When it is determined how to bring the template MR image stack and the incoming MR image stack in spatial correspondence with each other a calculation for generating warp information, describing the transformation of the template MR image stack may be performed. The transformation may be deformation fields describing the transformation of the template MR image stack. Alternatively, the transformation may be a non-rigid transformation, a transformation matrix or any number of such transformations in combination, possibly describing the transformations of portions of the template MR image stack, whereas an interpolation may be used between the portions. [0103] The template MR image stack may be actually deformed by the Image Warping Engine 114 in order to generate the warp information. However, according to an alternative, the warp information required for bringing the template MR image stack in spatial correspondence with the incoming MR image stack is determined without the actual spatial deformation of the template MR image stack being performed. [0104] The Image Warping Engine 114 , in some embodiments, warps each of the utilized CT image stacks from the Segmented Template Image Repository 118 using the generated warp information such that the shapes of its segmented structures overlap with the shapes of the automatically segmented structures generated by the Automatic Segmentation Engine for the incoming MR image stack, thereby generating a candidate synthetic CT image stack representing the incoming MR image stack. In one embodiment, the warping is achieved using known techniques from published image registration research. [0105] In one embodiment of the Image Warping Engine 114 , the space in between the structure shapes in the warped CT image stacks may be spatially translated to satisfy the new locations of the shapes while preserving smooth deformation in all parts of the image stack. In yet another embodiment, estimated deformation restrictions (i.e. elasticity, viscosity, stiffness, etc.) for various tissues may be taken into account during the deformation of tissue in between the structure shapes. [0106] In yet another embodiment of the Image Warping Engine 114 , an MR image stack from the Segmented Template Image Repository 118 may be warped in such way that a local image similarity metric between the incoming MR image stack and the warped MR image stack is optimized. The deformation field calculated from such warping may then be applied to the corresponding CT image stack from the Segmented Template Image Repository 118 , which may generate a candidate synthetic CT image stack. In such embodiment the warping of the MR image stack from the Segmented Template Image Repository 118 may be initialized according to any of the mentioned embodiments and additional translation of the shapes of aligned segmented structures may be restricted. [0107] The Image Warping Engine 114 need not necessarily perform warping of the template CT image stacks. Rather, a representation of the transformation to be made to the template CT image stack may be formed. This constitutes information of the relation between the template CT image stack to the acquired MR image stack, which may be used as input to how synthetic CT image stack is to be formed from the template CT image stacks, Image Fusion Engine [0108] The Image Fusion Engine 116 , in some embodiments, fuses the candidate CT image stacks generated by the Image Warping Engine 114 into a final synthetic CT image stack. In one embodiment, such fusion may be performed by choosing or combining values from one or more of the candidate synthetic CT image stacks, which may be selected using a mathematical method (e.g. histogram based, median value, etc.), or by comparing imaging similarities between warped template MR image stacks and the incoming MR image stack, or by utilizing statistical or machine learning methods, or by any combination thereof. In yet another embodiment, such fusion includes calculating an average or median value of all selected candidate synthetic CT image stacks, or performing a calculation using information from one or more candidate synthetic CT image stacks. In yet another embodiment, such fusion is performed locally, using information at or in the nearby of a corresponding local region in one or more of the candidate synthetic CT image stacks. In yet another embodiment, the correspondingly warped MR image templates or the correspondingly warped template structures are utilized in the fusion process. In yet another embodiment, such fusion is achieved using a combination of the described techniques. [0109] In yet another embodiment, the Image Fusion Engine 116 receives information about the warping to be applied to a template CT image stack such that when the Image Fusion Engine 116 determines that a portion of the template CT image stack is to be used in the fusion, the particular portion of the template CT image stack is warped. Hence, the entire template CT image stacks need not be warped. [0110] In yet another embodiment, a single template CT image stack is provided and warp information is generated for the single template CT image stack. This may be relevant e.g. when using a template CT image stack that has been acquired from the same patient as is imaged in the incoming MR image stack. In such case, it may not be necessary to fuse information from a plurality of template CT image stacks. Rather, the synthetic CT image stack may be formed from the single template CT image stack. [0111] Referring now to FIG. 3 , a flow chart for a method according to an embodiment of the invention will be described. The description of the method summarizes the method steps as described above in relation to the system. [0112] The method thus comprises receiving an acquired or incoming MR image stack, step 302 . The incoming MR image stack may be acquired by an MRI scanner. [0113] The incoming MR image stack is sent to the Automatic Segmentation Engine for analyzing the incoming MR image stack so as to automatically segment the incoming MR image stack, step 304 . [0114] Utilizing the segmentation and template structure information, e.g. in the form of previously segmented template MR image stacks, it is determined how to bring the location and/or geometry of the template structures, e.g. as represented in the template MR image stack, into alignment with the location and/or geometry of similar structures in the incoming MR image stack. Further, the spatial correspondence between the template MR image stack and the incoming MR image stack may be further improved by determining how to deform the template MR image stack in order to optimize an image similarity metric between the template MR image stacks and the incoming MR image stack. Thus, a spatial deformation of the template MR image stack may be determined, step 306 , representing a deformation that brings the template MR image stack in spatial correspondence with the incoming MR image stack. [0115] The determined spatial deformation may constitute warp information, which is in turn applied to template CT image stacks, which are respectively correlated to template MR image stacks. The warp information may thus provide a representation of how the template CT image stacks would be transformed, step 308 , in order to correspondingly bring the template CT image stacks into correspondence with the incoming MR image stack. [0116] Finally, an image fusion is performed, step 310 , in order to form a synthetic CT image stack based on fusioning of at least parts of the template CT image stacks after using the warp information, wherein the image fusion may e.g. take median or average value of the warped template CT image stacks or may stitch different parts of the warped template CT image stacks together. [0117] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” “comprising,” “includes” and/or “including” when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. [0118] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. [0119] The foregoing has described the principles, preferred embodiments and modes of operation of the present invention. However, the invention should be regarded as illustrative rather than restrictive, and not as being limited to the particular embodiments discussed above. The different features of the various embodiments of the invention can be combined in other combinations than those explicitly described. It should therefore be appreciated that variations may be made in those embodiments by those skilled in the art without departing from the scope of the present invention as defined by the following claims.

A method for generating synthetic electron density information based on an acquired magnetic resonance, MR, image stack is disclosed. The method comprises: analyzing the acquired MR image stack to automatically segment the acquired MR image stack; generating warp information for a template dataset comprising at least one template electron density information map and at least one template structure information, said generating comprising utilizing structure information of the acquired MR image stack and said template structure information in order to determine transformations bringing the template structures in spatial correspondence with the structures in the acquired MR image stack, wherein said generated warp information describes at least one transformation bringing the at least one template electron density information map in spatial correspondence with the acquired MR image stack; and forming synthetic electron density information corresponding to the acquired MR image stack based on at least part of a warped template electron density information map.

TECHNICAL FIELD [0001] The present invention relates to estimation of battery dynamics. BACKGROUND [0002] Accurate estimates of battery dynamics may be used to improve many vehicle control systems, such as a control system associated with regenerative brake blending, and in vehicles including increased electrical content. For example, battery dynamics estimation may enable enhanced prognostics and battery controls. To provide increased vehicle system control, a greater number of sensors are being included with a vehicle. Including a greater number of sensors may increase the burden on the electrical system of a vehicle, of which the battery is a major component. [0003] Several methods exist and are known in the art for estimating battery dynamics. However, existing methods relate primarily to “slow” battery dynamics and are typically limited to the battery state-of-charge (SOC). A battery also includes “fast” battery dynamics, which may include the battery voltage and the battery current. The “fast” battery dynamics may fluctuate at a rate much greater than the battery state-of-charge, thereby rendering estimations of state-of-charge unable to accurately reflect all battery dynamics. SUMMARY [0004] A method of adaptively estimating battery dynamics using an adaptive battery control system in operative communication with at least one battery includes estimating a battery terminal voltage, internal resistance, and current from a desired power request and from a plurality of battery dynamics inputs. Further, predicted battery terminal voltage and current, and an updated estimated battery internal resistance based on the estimated battery terminal voltage, the estimated battery internal resistance, and the estimated battery current are determined. BRIEF DESCRIPTION OF THE DRAWINGS [0005] One or more embodiments will now be described, by way of example, with reference to the accompanying drawings, in which: [0006] FIG. 1 is a schematic illustration of a vehicle battery control module in signal communication with a vehicle battery in accordance with the present disclosure; [0007] FIG. 2 is a flow chart illustrating a method of adaptively estimating battery dynamics using an adaptive battery control system in accordance with the present disclosure; [0008] FIG. 3 is a flow-chart illustrating a method of adaptively estimating battery dynamics using an adaptive battery control system in accordance with the present disclosure; and [0009] FIG. 4 is a flow-chart illustrating a method of adaptively estimating battery dynamics using an adaptive battery control system in accordance with the present disclosure. DETAILED DESCRIPTION [0010] Disclosed herein is an adaptive battery estimation control system, and a method of using the adaptive battery estimation control system in a vehicle having a battery, a vehicle electrical system, and a vehicle battery control module. The vehicle battery control module may comprise any combination of hardware, including but not limited to: microprocessors and computer memory devices; and software, the software operating to control the operation of the hardware and the vehicle battery. [0011] As defined herein, a battery may be any device or combination of devices operating to receive, store, and discharge an electrical charge. [0012] The adaptive battery estimation control system uses a plurality of sensors in signal communication with the vehicle battery control module to estimate ether or both battery voltage and battery current when the vehicle electrical system is placed under load or receives a charge. [0013] The adaptive battery estimator includes a plurality of modules that cooperate to process input signals received from a plurality of sensors associated with a vehicle and a vehicle electrical system. The adaptive battery estimator operates to evaluate the received input signals to determine the battery parameters including, but not limited to: battery voltage, battery state-of-charge, battery power, and battery rated capacity. As used herein the term “module” or “modules” is defined as one or more units capable of processing or evaluating signals input into or stored within the vehicle battery control module including a fixed battery estimator and an adaptive battery estimator. Each module may be a stand-alone unit or a plurality of units comprising hardware or software or a combination thereof. [0014] More particularly, in an embodiment, each of the plurality of sensors electronically communicates a battery voltage signal to a vehicle battery control module. The vehicle battery control module also electronically receives a power request. The power request may be any electrical load placed upon a vehicle electrical system and may be made by a vehicle user or a vehicle system. [0015] The vehicle battery control module may also electronically receive an actual or reported and estimated state-of-charge signal used to estimate open circuit voltage of the battery from the battery state-of-charge sensor. The control module 14 , using estimated open circuit voltage of the battery and the power request, determines an estimated and a predicted voltage; an estimated and a predicted current; and an estimated internal resistance, or any combination thereof. [0016] FIG. 1 illustrates an adaptive battery estimation control system 10 in a vehicle (not shown) having a vehicle battery control module 14 in bi-directional communication with a plurality of sensors, including a battery terminal voltage sensor 16 A, provided to communicate signals from a number of vehicle systems and in particular from a battery 18 to the vehicle battery control module 14 . [0017] More particularly, the control module 14 includes a fixed battery estimator 32 used to determine an estimated battery terminal voltage, an estimated battery internal resistance, and an estimated battery current based on a measured or estimated terminal voltage and a desired power request. Control module 14 also includes an adaptive battery estimator 34 used to determine a predicted battery terminal voltage, a predicted battery current, and an estimated battery internal resistance based on the measured battery terminal voltage, the estimated battery internal resistance, and the estimated battery current input into the adaptive battery estimator 34 from the fixed battery estimator. [0018] In an embodiment, when an open circuit voltage of the battery is a function of the battery's SOC, the vehicle battery control module 14 is placed in electrical and signal communication with a SOC estimator module 22 . The SOC estimator module 22 operates to provide the vehicle battery control module 14 with an estimated SOC, or an estimated open-circuit voltage (estimated V oc ). [0019] In one embodiment, the adaptive battery estimation control system 10 estimates and predicts battery dynamics including an estimated battery terminal voltage in response to changing vehicle electrical system conditions based on battery SOC and a desired power request. [0020] In an embodiment, shown in FIG. 1 , the fixed battery estimator 32 includes a SOC estimator 22 , an a priori battery resistance estimator 23 , a battery current estimator 25 , and a battery terminal voltage estimator 37 . The fixed battery estimator 32 is in signal communication with the battery 18 , with a desired power request signal 17 A, and with the adaptive battery estimator 34 when the battery 18 is not in a low battery power state or condition, and thus, when SW 1 and SW 2 are closed. [0021] In an embodiment when the battery 18 is not in a low battery state, the fixed battery estimator 32 receives a desired power request, P* b (k) at a time sample k via desired power signal 17 A, from a remote location, a state-of-charge signal 17 B from the battery 18 and outputs both an estimated battery terminal voltage {circumflex over (V)} b 0 (k) via estimated battery terminal voltage signal 27 A and an estimated internal battery resistance {circumflex over (R)} b o (k) via estimated internal battery resistance signal 27 B to the adaptive battery estimator 34 . [0022] In an embodiment when the battery 18 is not in a low power state, the state-of-charge signal 17 B is input into the state-of-charge estimator 22 to estimate an open circuit voltage {circumflex over (V)} oc (k) via estimated open circuit voltage signal 17 F, wherein the open circuit voltage {circumflex over (V)} oc (k) is a function of the battery state-of-charge, wherein the state-of-charge signal 17 B is based on an estimated state-of-charge or a reported state-of-charge. The open circuit voltage signal 17 F, an internal battery resistance signal 17 E, and the desired power request signal 17 A are input into the fixed battery terminal estimator 37 to determine the estimated battery terminal voltage {circumflex over (V)} b 0 (k). [0023] In an embodiment, the estimated battery terminal voltage {circumflex over (V)} b 0 (k) is output via an estimated battery terminal signal 27 A to both the adaptive battery estimator 34 and back to the fixed battery estimator 32 via a feedback control loop 35 A, which includes signals 27 A, 29 A, and 17 E. [0024] The feedback control loop 35 A inputs the estimated battery terminal voltage signal 27 A from the last time sample (k−1) into the battery current estimator 25 , wherein the battery current estimator 25 determines an estimated current Î b (k) via an estimated battery current signal 29 A. The estimated battery current signal 29 A is input into the a priori internal battery resistance estimator 23 to determine an estimated internal battery resistance {circumflex over (R)} b o (k) via an estimated internal battery resistance signal 17 E, which is then input into the fixed battery terminal voltage estimator 37 and from there also to the adaptive battery estimator 34 via line 27 B. [0025] More particularly, the battery current estimator 25 determines an estimated battery current signal 29 A based on both the desired power request signal 17 A, and the estimated battery terminal voltage signal 27 A from the last time sample (k−1). The feedback control loop 35 A operates to continuously update and estimate the internal battery resistance {circumflex over (R)} b o (k). [0026] With additional reference to FIGS. 2-4 which illustrate various methods in accordance with the present disclosure, bracketed reference numerals (#) correspond to portions of such methods. In an embodiment, a method ( 60 ) for adaptively estimating and predicting battery dynamics is shown in FIG. 2 . More particularly, the control module 14 includes a fixed battery estimator 32 ( 36 ) used to determine an estimated battery terminal voltage, an estimated battery internal resistance, and an estimated battery current based on an estimated open circuit voltage and a desired power request, and then uses an adaptive battery estimator 34 to determine a predicted battery terminal voltage, a predicted battery current, and an estimated battery internal resistance based on the estimated battery terminal voltage, the estimated battery internal resistance, and the estimated battery current input into the adaptive battery estimator 34 ( 70 ) from the fixed battery estimator 32 ( 36 ). [0027] Initially, the battery open circuit voltage ({circumflex over (V)} oc (k)) is determined ( 24 ) by the vehicle battery control module 14 as a function of the SOC. The SOC may be either estimated or reported. In an embodiment wherein the SOC is reported, the SOC may be reported as information, which is typically collected at the battery cell during battery cell characterization. In an embodiment where the SOC is estimated, the SOC may be estimated by a variety of statistical estimation methods, as is known in the art. [0028] Determination of {circumflex over (V)} oc (k) (24) may be made using Equation (1): [0000] {circumflex over (V)} oc ( k )= f (SOC( k ))  (1) [0000] wherein {circumflex over (V)} oc is the determined open circuit voltage of the battery, k represents a discrete time sample and comprises an integer, and SOC is the state-of-charge. The sampling rate T (not shown) may vary. In one embodiment, the time sampling rate T is 8 milliseconds. [0029] Once {circumflex over (V)} oc is determined, as illustrated in FIG. 2 , a preliminary estimation of battery current is determined ( 26 ) by the battery current estimator 25 using Equation (2): [0000] Î b ( k )= P* b ( k )/ {circumflex over (V)} b ( k− 1)  (2) [0000] wherein Î b is the preliminary estimation of battery current, k is the time sample as disclosed in Equation (1), P* b is desired power request representing power flowing out of the battery 18 , and {circumflex over (V)} b is the estimated battery terminal voltage of the battery 18 . [0030] The determined preliminary estimate of battery current (Î b ) ( 26 ) is then used to compute the battery internal resistance ({circumflex over (R)} b o ) ( 28 ) using Equation (3): [0000] R ^ b o  ( k ) = { KeHVBR_R  _HVBatResistanceDisChg , if   I ^ b  ( k ) > 0 KeHVBR_R  _HVBatResistanceChg , if   I ⋒ b  ( k ) ≤ 0 ( 3 ) [0000] wherein {circumflex over (R)} b o is the battery internal resistance, k is the time sample and comprises an integer, KeHVBR_R_HVBatResistanceDisChg is a variable corresponding to the battery 18 being in a discharge state if Î b (k)>0 as determined in Equation (2), and KeHVBR_R_HVBatResistanceChg is a software functionality module corresponding to the battery 18 being in a charging state if Î b (k) is a value that is less than zero. [0031] Next, as illustrated in FIG. 2 , each of the battery circuit open voltage ({circumflex over (V)} oc (k)), the preliminary estimate of battery current (Î b ), and the battery internal resistance ({circumflex over (R)} b o ) parameters are used to estimate the battery terminal voltage ( 30 ) through a relationship derived from Equations (1) through (3), wherein the relationship defines estimated battery terminal voltage {circumflex over (V)} be 0 (k) determined by the fixed battery estimator 32 . The fixed battery estimator determines a linear battery terminal voltage using Equation (4): [0000] V ^ b 0    e  ( k ) = V ^ oc  ( k ) + V ^ oc 2  ( k ) - 4  R ^ b 0  ( k )  P b *  ( k ) 2 ( 4 ) [0000] wherein each of the variables are defined in Equations (1)-(3). [0032] Once determined, {circumflex over (V)} be 0 (k) and other estimated signals are input ( 68 ) into the adaptive battery estimator 34 . A predicted voltage value {circumflex over (V)} bp 0 (k) via predicted battery terminal voltage signal 33 A is determined by the non-linear adaptive battery estimator 34 ( 70 ), enabling the vehicle battery control module 14 to track, estimate, and predict battery dynamics online. [0033] In an embodiment, the non-linear adaptive battery estimator 34 uses logic to determine the predicted voltage value {circumflex over (V)} bp 0 (k) using the estimated battery terminal voltage {circumflex over (V)} b e 0 (k) derived from the fixed battery estimator 32 as determined in Equation (4), as represented in Equation (5): [0000] V ^ b    p  ( k ) ≅ V ^ b 0    e  ( k ) + ∂ V b ∂ R b   R b = R ^ b 0  ( k )  × d   R ^ b  ( k ) ( 5 ) [0000] wherein R b is an updated estimated internal battery resistance of the battery 18 determined by the fixed battery estimator 32 and d{circumflex over (R)} b (k) is a change in the estimated internal battery resistance as determined by the adaptive battery estimator in Equation (8) below, and wherein [0000] ∂ V b ∂ R b   R b = R ^ b 0  ( k ) [0000] is a change in the estimated battery terminal voltage with respect to a change in the estimated internal battery resistance. [0034] More particularly, Equation (5) calculates [0000] ∂ V b ∂ R b   R b = R ^ b 0  ( k ) [0000] as follows: [0000] ∂ V b ∂ R b   R b = R ^ b 0  ( k ) = - P b *  ( k ) V ^ oc 2  ( k ) - 4  R ^ b 0  ( k )  P b *  ( k ) ( 6  a ) [0035] In one embodiment, [0000] ∂ V b ∂ R b   R b = R ^ b 0  ( k ) [0000] represents a statistical sensitivity factor determined ( 38 ) in Equation (6a): [0000] φ  ( k ) = ∂ V b ∂ R b   R b = R ^ b 0  ( k ) ( 6  b ) [0000] wherein φ represents the statistical sensitivity factor and k represents a time sample and comprises an integer. [0036] Using φ determined in Equation (6b), the adaptive battery estimator 34 then determines a covariance P(k) ( 40 ), wherein the covariance is determined using Equation (7): [0000] P  ( k ) = 1 α  [ P  ( k - 1 ) - P 2  ( k - 1 )  φ 2  ( k ) α + P  ( k - 1 )  φ 2  ( k ) ] ( 7 ) [0000] wherein α is a fixed variable. [0037] After updating the covariance, the adaptive battery estimator 34 calculates an update to the battery internal resistance ({circumflex over (R)} b o ) (42) using Equation (8): [0000] d   R ^ b  ( k ) = d   R ^ b  ( k - 1 ) + 1 α + P  ( k - 1 )  φ 2  ( k )  P  ( k - 1 )  φ  ( k )  ( V b  ( k ) - V ^ b  ( k - 1 - d ) ) ( 8 ) [0000] wherein d represents a corrective factor that may provide tuning or correction of measurement and of lag in measurement. Additionally, the corrective factor d may provide correction for other battery or system parameters, the tuning of which would provide an optimization of the function of the adaptive battery control module 14 . [0038] In an embodiment, the value of [0000] φ  ( k ) = ∂ V b ∂ R b   R b = R ^ b 0  ( k ) [0000] is substituted in Equation (5) with φ(k) derived from Equations (6a) and (6b) to determine the predicted battery terminal voltage as {circumflex over (V)} b p (k) ( 44 ) defined in Equation (9): [0000] {circumflex over (V)} b p ( k )≅ {circumflex over (V)} b 0 ( k )+φ( k )* d{circumflex over (R)} b ( k )  (9) [0039] During use of a vehicle including a battery 18 , the internal resistance, interchangeably referred to herein as impedance, of the battery 18 may change, depending upon the operating condition of the battery 18 . The operating conditions of the battery 18 may include the battery 18 being charged by a power source, the battery 18 being discharged to a load, or the battery 18 maintaining a given charge. To account for variations in battery impedance, another embodiment is provided, wherein an adaptive battery estimator 46 is provided to account for differences in battery impedance caused by differing battery operating conditions. [0040] In an embodiment illustrated in FIG. 3 , a method ( 84 ) operates to adaptively estimate and predict battery dynamics. Initially, a fixed battery estimator 66 ( 36 ) operates to estimate the battery dynamics in the same manner as the fixed battery estimator 32 as shown in FIG. 2 . The updated estimated internal battery resistance reflecting a change in the internal battery resistance is calculated by an adaptive battery estimator 46 depending on whether the battery is in a charging or a discharging state ( 48 ), ( 49 A), ( 49 B). The adaptive battery estimator 46 determines the statistical sensitivity factor φ(k) ( 38 ) as disclosed in Equations (6a) and (6b), and the covariance P(k) ( 40 ) as disclosed in Equation (7). However, unlike the adaptive battery estimator 34 ( 70 ), the adaptive battery estimator 46 ( 72 ) substitutes Equation (8) with Equations (10a) and (10b) as follows to determine d{circumflex over (R)} b (k). The selected d{circumflex over (R)} b (k) is then used to calculate the predicted battery terminal voltage {circumflex over (V)} b p (k) as disclosed in Equation (9) and determines whether the battery is in a discharging state wherein the power P*(k) is greater than zero or a charging state wherein P*(k) is less than or equal to zero ( 48 ) and includes the following process, to be used by adaptive battery estimator 46 , according to the value of P*(k), as shown in Equations (10a) and (10b): [0000] If P * ( k ) < 0 , ( 10  a ) then d   R ^ b , chg  ( k ) = d   R ^ b , chg  ( k - 1 ) + 1 a + P  ( k - 1 )  φ 2  ( k )  P  ( k - 1 )  φ  ( k )  ( V b  ( k ) - V ^ b  ( k - 1 - d ) ) wherein d   R ⋒ b  ( k ) = d   R ^ b , chg  ( k ) . If P * ( k ) ≥ 0 ( 10  b ) d   R ^ b , dischg  ( k ) = d   R ^ b , dischg  ( k - 1 ) + 1 a + P  ( k - 1 )  φ 2  ( k )  P  ( k - 1 )  φ  ( k )  ( V b  ( k ) - V ^ b  ( k - 1 - d ) ) [0000] wherein d{circumflex over (R)} b (k)=d{circumflex over (R)} b,dischg (k). In Equations (10a) and (10b), d{circumflex over (R)} b,chg is the impedance of the battery 18 when the battery 18 is in a charging operating condition and d{circumflex over (R)} b,dischg is the impedance of the battery 18 when the battery 18 is in a discharging operating condition. [0041] In an embodiment, the adaptive battery estimator 46 may switch between d{circumflex over (R)} b,dischg ( 49 A) and d{circumflex over (R)} b,chg ( 49 B) of Equations (10a) and (10b), using a battery impedance corresponding to a discharge state of operation of the battery 18 , or a battery impedance corresponding to a charging state of the battery 18 , represented by d{circumflex over (R)} b,dischg and d{circumflex over (R)} b,chg , respectively, in the above equations and illustrated in FIG. 3 . [0042] In another embodiment a method ( 90 ) of adaptively estimating and predicting battery dynamics is shown in FIG. 4 . Adaptive battery estimator 80 estimates and predicts battery dynamics including an estimated battery terminal voltage in response to changing vehicle electrical system conditions based on a measured battery terminal voltage, a maximum battery rated capacity (E o ) and a desired power request when the battery 18 is in a low power state or condition. [0043] In another embodiment, the adaptive battery estimator 80 determines an estimate of battery dynamics without requiring an estimate of the V oc of the battery 18 when the battery is in a low power condition. The battery terminal voltage V b is not estimated using the fixed battery estimator 66 , but rather is determined from a measured battery terminal voltage V(k) and a maximum rated capacity of the battery E o representing a nominal energy storage capacity of the battery. In the low battery power condition embodiment, SW 1 and SW 2 are opened, thereby bypassing the fixed battery estimator for determining an open circuit voltage. Instead, SW 3 and SW 4 are closed to input voltage and battery capacity signals 17 C and 17 D, respectively, into the adaptive battery estimator 80 to generate predicted battery terminal voltage signal 33 A. A feedback control loop 35 B, formed between the adaptive battery estimator 80 , the battery current estimator 25 and the a priori battery resistance estimator 23 is used to update the internal battery resistance {circumflex over (R)} b,chg in a similar manner as described with respect to feedback control loop 35 A, except that the predicted battery terminal voltage in feedback control loop 35 B is input into the battery current estimator 25 from a predicted battery voltage signal 33 A instead of signal line 27 A to update and input both the estimated battery resistance and the estimated battery current into the adaptive battery estimator 80 . [0044] In an embodiment, the vehicle battery control module 14 samples and holds measured battery voltage during periods of low battery power ( 52 ). The vehicle battery control module 14 then operates to determine a rate limit ( 54 ) based upon the maximum rated capacity E o of the battery 18 . The vehicle battery control module 14 then inputs the measured terminal voltage from the battery terminal voltage signal 17 C and the estimated battery capacity E o from the estimated battery capacity signal 17 D into the adaptive battery estimator 80 to generate a first estimated battery terminal voltage {circumflex over (V)} oc (k) when k equals 1 and a predicted battery terminal voltage when k is greater than 1 ( 55 ). The estimated or predicted battery voltage signal 33 A is then input into feedback control loop 35 B. The adaptive battery estimator 80 operates to adaptively estimate battery dynamics using Equations (11a)-(11c): [0000] If | P *( k )|< P {circumflex over (V)} oc ( k )= V ( k )  (11a) [0000] If P *( k )>0 then, {circumflex over (V)} oc ( k )=Rate — lim[{circumflex over (V)} oc ( k− 1)− dV ( k )]  (11b) [0000] If P *( k )<0 {circumflex over (V)} oc ( k )=Rate — lim[{circumflex over (V)} oc ( k− 1)+ dV ( k )]  (11c) [0045] Instead of using V oc for battery dynamics estimation, as is disclosed in FIGS. 2-4 , another embodiment determines a rate limit of the change in battery voltage ( 54 ). The rate limit is formed as a function of the measured battery voltage and the maximum battery rated capacity E o communicated to the adaptive battery estimator 80 during when the battery is operating in a low battery condition. The change in measured battery voltage may be incremental and is determined using Equation (12): [0000] dSOC est  ( k ) = - P × ( k )  dT / E 0   dV  ( k ) = ∂ V ∂ SOC   SOC est  ( k )  × dSOC est  ( k ) ( 12 ) [0000] wherein SOC est is the estimated state-of-charge, E 0 is the maximum battery rated capacity, and k is the time sample comprising an integer. [0046] The estimated battery terminal voltage V oc from the last time sample (k−1) is then input ( 68 ) into feedback control loop 35 B to determine an estimated battery current ( 26 ) and to update the internal battery resistance ( 28 ) as disclosed in Equations (2) and (3). For each time sample where k is greater than 1, the estimated voltage {circumflex over (V)} oc (k) from the last time sample becomes the predicted voltage. In the embodiment where the battery is in a low power state, SW 1 and SW 2 are opened, and SW 3 , SW 4 , and SW 5 are closed. The adaptive battery estimator 80 adaptively predicts battery dynamics and uses battery dynamics inputs and equations (11a)-(11c) and (12) to determine a sensitivity factor ( 38 ), a covariance ( 40 ), an estimated or a predicted battery terminal voltage 33 A ( 44 ). [0047] The disclosure has described certain preferred embodiments and modifications thereto. Further modifications and alterations may occur to others upon reading and understanding the specification. Therefore, it is intended that the disclosure not be limited to the particular embodiment(s) disclosed as the best mode contemplated for carrying out this disclosure, but that the disclosure will include all embodiments falling within the scope of the appended claims.

An adaptive battery estimation control system includes a fixed and adaptive battery estimators effective for a battery parameter estimations across a wide range of dynamic battery operational conditions.

PRIORITY CLAIM This patent application claims the benefit of the priority date of U.S. provisional patent application Ser. No. 60/685,216, filed on May 27, 2005 and entitled SUB-DIFFRACTION-LIMIT (SDL) PIXELS. The entire contents of this provisional patent application are hereby expressly incorporated by reference. TECHNICAL FIELD The present invention relates generally to solid state imaging. The present invention relates more particularly to the use of sub-diffraction-limit (SDL) pixels for imaging, such as to emulate the contemporary silver halide emulsion film process. BACKGROUND The relentless drive to reduce feature size in microelectronics has continued now for several decades and feature sizes have shrunk in accordance with the prediction of Gordon Moore in 1975. While the repeal of Moore's Law has been anticipated for some time, we can still confidently predict that feature sizes will continue to shrink in the near future. Using the shrinking-feature-size argument, it became clear in the early 1990's that it would be possible to put more than 3 or 4 charge coupled device (CCD) electrodes in a single pixel. Thus, the complimentary metal oxide (CMOS) active pixel sensor concept was born. The effective transistor count in most CMOS image sensors has hovered in the 3-4 transistor range, and if anything, is being reduced as pixel size is shrunk by shared readout techniques. The underlying reason for pixel shrinkage is to keep sensor and optics costs as low as possible as pixel resolution grows. Camera size has recently become highly important in the rapidly expanding camera-phone marketplace. Concomitant with the miniaturization of camera components such as sensors and optics is the miniaturization of optical system components such as actuators for auto-focus and zoom in megapixel camera phones. We are now in an interesting phase in the development of image sensors—for both CCDs and CMOS active pixel sensors. The physical dimensions of the pixel are becoming smaller than the diffraction limit of light at the wavelengths of interest. A perfect lens can only focus a point of light to a diffraction-limited spot, known as an Airy disk and the Airy disk is surrounded by higher order diffraction rings. The Airy disk diameter D A is given by the equation: D A =2.44 λF# Where λ is the wavelength and F# is the F-number of the optical system. For example, at 550 nm, and F-number of 2.8, the Airy disk diameter is 3.7 μm. Yet, pixel sizes in megapixel image sensors are at this size and smaller today. We refer to pixel sizes smaller than the 550 nm Airy disk diameter as sub-diffraction-limit (SDL) pixels. Today it is readily possible to build a 6-T SRAM cell in less than 0.7 μm 2 using 65 nm CMOS technology. Smaller device are being prototyped. However, significant issues exist for a 0.25 μm 2 pixel, even though it might be tempting to make a 2 megapixel sensor with 1 mm diagonal using such small pixels. For example, the resolution of the sensor would be well beyond the diffraction limit. In fact, over 40 pixels would fit inside the Airy disk and well over a billion pixels (one gigapixel) can fit on a single chip. Although it is possible to construct such an imager, contemporary imagers do not take advantage of this possibility. Further, contemporary practice does not contemplate the best ways to implement such a device. In view of the foregoing, it is beneficial to provide implementations and practical applications for such SDL pixels. More particularly, it is desirable to provide a method for providing a digital film sensor that emulates, at least to some degree, contemporary silver halide film. BRIEF SUMMARY Systems and methods are disclosed herein to provide a digital film sensor (DFS), such as a gigapixel DFS. In this manner, the contemporary silver halide process can, at least to some degree, be emulated. For example, in accordance with an embodiment of the present invention, an imaging system can comprise an imager having a plurality of sub-diffraction-limit pixels, referred to herein as jots. The imaging system can also comprise a readout circuit that is in electrical communication with the imager. The readout circuit can be configured to form an image by defining neighborhoods of the jots. A local density of exposed jots within a neighborhood can be used to generate a digital value for a single pixel of the image. That is, the digital value can depend upon how many jots within a neighborhood have been exposed (registered a hit by a photon). A neighborhood can comprise either a single jot or a plurality of jots. Every neighborhood does not necessarily comprise the same number jots. A neighborhood can comprise any desired number of jots. For example, some neighborhoods can comprise one jot, other neighborhoods can comprise two jots, yet other neighborhoods can comprise three jots, and yet other neighborhoods can comprise more than three jots. A neighborhood can comprise a plurality of jots from a single exposure (a single frame). Alternatively, a neighborhood can comprise a plurality of jots from a plurality of exposures. The number of jots used to define a neighborhood is variable. A jot may belong to one neighborhood for one exposure and to a different neighborhood for another exposure. The number of jots used to define a neighborhood can be variable according to a region growing process. The number of jots used to define a neighborhood can be variable according to either a spatial or a temporal region growing process. The number of jots used to define a neighborhood can be variable according to both a spatial and a temporal region growing process. The region growing process can be a process whereby the size of the neighborhood is determined dynamically. That is, various sizes of neighborhoods are tried and the size providing the best results is used to form an image. For example, the size of each neighborhood can be increased until a resolution maximum is defined and the neighborhood size that provides the resolution maximum can be used to form the image. An image can be divided into any desired number of sub-images and the region growing process can be performed independently for each sub-image. The neighborhoods can have different sizes as a result of this region growing process. For example, neighborhoods comprised of single jots may provide maximum resolution in one portion of an image, while neighborhoods comprised of four jots may provide maximum resolution in another part of an image. Each jot can be sensitive to a single photon of light. Alternatively, each jot can require more than one photon to register a hit. The size of the jots within an imager does not have to be uniform. Each jot can be read out as a logical “1” or a logical “0”. The imager can comprise color filters covering a plurality of the jots so as to facilitate color imaging therewith. Different colored filters can cover individual jots or groups of jots in the fashion of the Bayer filters that are used in contemporary color imaging sensors. A digital processor can be configured to facilitate the generation of the image. Optionally, the digital processor can be integrated on the same chip as the jots. The processor can be configured to use an algorithm to form an image from a jot pattern. The algorithm can be dynamically varied so as to trade spatial resolution for light sensitivity. Thus, when less light is available the number of jots in a neighborhood can be increased. The processor can be configured to use a single or a plurality of readouts of the jots to form a single image. A jot may comprise an integrating silicon photodetector, a high gain amplifier, a reset circuit, and a selection switch for reading out the jot. The imager can be made using a CMOS-compatible process. Each of the jots can have a total area less than 1 square micron. A method for digital imaging can comprise setting a grain size digitally. The grain size can be set so as to be the smallest grain size that provides a picture having acceptable quality as measured using a parameter other than grain size. For example, the parameter can be intensity resolution. The method can comprise digitally developing an image. The method can comprise using a plurality of jots in a manner that provides a desired balance between intensity resolution and spatial resolution. The method can comprise setting a grain size of an imager so as to provide a desired effective International Standards Organization (ISO) speed/resolution. The method can comprise selecting a grain size after exposure so as to enhance image quality. The method can comprise performing a region growing image processing function. The method can comprise determining a jot count of a grain based upon a light level. The method can comprise reading a plurality of jots more than once per exposure. Different jots can be read during each reading thereof. The method can comprise adding exposures such that grain construct is both spatial and temporal. The method can comprise using different mapping on consecutive readouts so as to dither grain position. The method can comprise varying a grain size during a plurality of readouts of an exposure. The method can comprise mapping light density of exposed jots to define intensity. Light density of exposed jots with overlapping neighborhoods can be mapped to define intensity. Light density of exposed jots with non-overlapping neighborhoods can be mapped to define intensity. The method can comprise mapping jots to define a pixel image. This invention will be more fully understood in conjunction with the following detailed description taken together with the following drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing the relationship between the size of an exemplary Airy disk and exemplary SDL pixels; FIG. 2 is an exemplary chart showing the density of exposed grains versus exposure for film and digital sensors; FIG. 3 is a semi-schematic diagram showing an exemplary array of jots according to an embodiment of the present invention, wherein a plurality of the jots have registered photon hits; FIG. 4 is a semi-schematic diagram showing the array of FIG. 3 , wherein the jots have been digitally developed using 4×4 neighborhoods according to an embodiment of the present invention; FIG. 5 is a semi-schematic diagram showing the array of FIG. 3 , wherein the jots have been digitally developed using 3×3 neighborhoods according to an embodiment of the present invention; and FIG. 6 is a semi-schematic diagram showing an imaging system comprising an SDL imager and a readout circuit/processor according to an embodiment of the present invention. Embodiments of the present invention and their advantages are best understood by referring to the detailed description that follows. It should be appreciated that like reference numerals are used to identify like elements illustrated in one or more of the figures. DETAILED DESCRIPTION OF THE INVENTION Referring now to FIG. 1 , the relationship between the size of an exemplary Airy disk 11 , e.g., an Airy disk for light having a wavelength of 550 nm, and exemplary sub-diffraction-limit (SDL) pixels 12 is shown graphically. Airy disk 11 has a diameter of 3.7 μm. SDL pixels 12 are square and are 0.5 μm on a side. Of course, the actual size of an Airy disk depends upon the wavelength of light being used to form the Airy disk and the size of the SDL pixels can be larger or smaller than 0.5 μm. As can be seen the, Airy disk 11 is substantially larger than each individual SDL pixel 12 and a plurality of SDL pixels 12 can thus fit within Airy disk 11 . According to an embodiment of the present invention, sub-diffraction-limit (SDL) pixels can be used in a new solid-state imaging paradigm. More particularly, SDL pixels can be used in a digital imaging emulation of the well known silver halide emulsion film process. The SDL pixels can be used in a binary mode to create a gigapixel digital film sensor (DFS). According to an embodiment of the present invention, oversampling of the SDL pixels can be performed. For example, the optical resolution of an image can be highly oversampled. For SDL pixels, such oversampling can mitigate color aliasing problems, such as those that occur due to the use of color filter arrays. Further, a diffraction effect can be used to eliminate the need for anti-aliasing optical filters. For deep-SDL pixels (those SDL pixels having a diameter substantially less than one micron), improved resolution of the optical image can be achieved using digital signal processing. According to an embodiment of the present invention, SDL pixels are used in the emulation of film. In film, silver halide (AgX) crystals form grains in the sub-micron to the several micron size range. A single photon striking the grain can result in the liberation of a single silver atom. This grain is effectively tagged as exposed and constitutes a latent image. In the subsequent wet chemical development process, the one silver atom results in a runaway feedback process that chemically liberates all the silver atoms in the exposed grain. This liberation of silver atoms leaves an opaque spot in the film, where the silver halide has been converted to metallic silver. Unexposed grains are washed away. The image intensity is thus proportional to a local density of silver grains. Referring now to FIG. 2 , a chart shows the density of exposed grains versus the log exposure thereof for a typical silver halide emulsion film. As indicted by the chart, the probability that any particular grain is exposed under illumination grows linearly at first, but only eventually approaches unity. This process gives rise to film's particular D-log H contrast curve, where D is density and H is light exposure. The smaller the grain size, the lower the probability that the grain will be struck by a photon in a given exposure, and the slower the film speed will be since more light is required to ensure a high probability that all grains are struck by photons. However, the spatial resolution of the image is determined by grain size, with smaller grain sizes and slower film having higher image resolution. In a developed film image, the grains are binary-like since they are either exposed or not exposed. The local image intensity is determined by the density of exposed grains, or in digital parlance, by the local spatial density of logical 1's. According to an embodiment of the present invention, the concept of binary-like development of images in silver halide emulsion film is emulated to provide a digital-film sensor (DFS). For example, an embodiment of the present invention can comprise an array of deep-SDL pixels. With sufficiently high conversion gain and sufficiently low readout noise, the presence of a single photoelectron can be determined. In practice, several photoelectrons can contribute to pushing the output signal above some threshold. However, either single photon or multiple photon sensitivity can be used. From the discussion above, it is evident that a pixel that only needs to detect a single photoelectron has much lower performance requirements for full-well capacity and dynamic range than an analog pixel in a conventional image sensor. According to one or more embodiments of the present invention, the implementation of a jot can be accomplished is any of several ways. A brute force approach can be to make a conventional active pixel with very high conversion gain (low capacitance). Other approaches include using avalanche or impact ionization effects to achieve in-pixel gain, as well as the possible application of quantum dots and other nanoelectronics devices to define the jots. Stacked structures are also possible, especially since performance requirements are reduced. Of course, it is generally desirable to minimize dark current. At the start of the exposure period, the jot can be reset to a logical ‘0’. If the jot is subsequently hit by a photon during an exposure, then the jot is set to a logical ‘1’, either immediately or upon readout. This can be accomplished in a fashion analogous to that performed with memory chips that have been used as image sensors. Due to the single-bit nature of the analog-to-digital conversion resolution, high row-readout rates can be achieved, thus facilitating scanning of a gigapixel sensor having approximately 50,000 rows in milliseconds and thereby enabling multiple readouts per exposure or frame. The read out binary image can be digitally developed to provide a conventional image having somewhat arbitrary pixel resolution. Such development can be accomplished using a two step process. According to this two step process, image intensity resolution can be traded for spatial resolution. Referring now to FIG. 3 , a representative portion of an exemplary digital film sensor (DFS) can comprise a plurality of jots 32 arranged in an array 31 according to an embodiment of the present invention. Expose jots 33 are indicated as being black. Either one photon or a plurality of photon may be required to expose a jot. Referring now to FIG. 4 , a neighborhood 41 can be defined herein as being comprised of a group of jots. Each neighborhood of FIG. 4 is a 4×4 array of jots. Thus, each 4×4 array of FIG. 4 defines one neighborhood 41 . Alternatively, a neighborhood can comprise any other number, e.g., 2, 3, 5, 20, 100, of jots. Indeed, a neighborhood can even comprise a single jot, if desired. Each neighborhood is at least somewhat analogous to a grain of contemporary silver halide film. The terms neighborhood and grain can thus generally be used interchangeably herein. According to one embodiment of the present invention, if any jot in a grain or neighborhood 41 has been hit by a photon and is a logical ‘1’, the neighborhood is considered exposed and all jots in the neighborhood are set to ‘1’. The digital development process allows the flexibility of setting a grain or neighborhood size during readout to adjust the effective speed, e.g. International Standards Organization (ISO) speed of the DFS. Referring now to FIG. 5 , according to an embodiment of the present invention a region-growing approach can be used for digital development. Different sizes of neighborhoods can be tried during an exposure. Alternatively, the size of a neighborhood 41 can be selected to optimize image quality after the exposure. Thus, the first step of digital development can be performed as a region-growing image processing function. In any case, the development can be accomplished in a jot area-amplification fashion. This first step of digital development can be used in very high jot-count image sensors under low light conditions and corresponds to large-grain film emulsions for very high film speed. Unlike film where the grain boundaries are fixed during an exposure, it is possible to provide an imaging process where the jots are read out several times during a single exposure. The exposures can be added (logically ‘OR’d) together so that the grain construct is both spatial and temporal. The neighborhood mapping function can be different for each readout. That is, the number and/or location of jots in each neighborhood can be different for each readout. The use of different neighborhood mapping functions for each readout is somewhat analogous to dithering the grain position in a film emulsion during exposure, and perhaps even varying the grain size during the exposure. In the second step of digital development, the grains which form a binary image can be converted to a conventional digital image that contains pixels with intensity values between 0 and 255, for example. In this case, a local density of exposed grains can be mapped into a pixel image. The more exposed grains in a neighborhood, the higher the pixel value. Neighborhoods can overlap or can be distinct. If they overlap, this second step is like a blurring convolution process followed by subsampling. At high magnification, a conventional film image appears to be binary due to the presence or absence of silver grains. But, at the lower magnifications used for digitizing film, the same image appears as a continuous gray tone that can be digitized into an array of pixels. According to an embodiment of the present invention, digital color imaging can be performed in a manner analogous to the procedure used in contemporary color image sensors. Jots can be covered with color filters. Red (R), green (G), and blue (B) jots can be treated separately and later the digitally-developed images combined to form a conventional RGB image. R, G, and B jots need not appear at the same spatial frequency, and since the deep-SDL nature of the jot pitch results in blurring from diffraction effects, color aliasing is not an issue. Like film, we expect such a jot-based DFS to exhibit D-log H exposure characteristics. This is true because the physics and mathematics of jot exposure are nominally very similar to those of film. The dynamic range can be large and the exposure characteristics more appealing for photographic purposes. The DFS imaging may be superior to contemporary imaging techniques. One or more embodiments of the present invention provide for the use of deep-SDL pixels and introduce a paradigm shift with respect to contemporary solid-state image sensors. Pixel sizes can be measured in nanometers, conversion gain becomes extremely large, charge-handling capacity can be minute, and pixel resolution can be increased by orders of magnitude. Referring now to FIG. 6 , an SDL imaging system is shown. According to an embodiment of the present invention, light from a subject passes through optics 61 and is incident upon SDL imager 62 . SDL imager 62 comprises a plurality of jots that can be organized into neighborhoods so as to emulate, at least to a degree, the effect of grain structure in contemporary silver halide film. Such organization of the jots into neighborhoods can be performed by readout circuit and processor 63 , as discussed in detail above. Information from readout circuit and processor 63 can be provided to a memory for storage, to another processor for further processing (color balance, compression, etc.) and/or to a display. One or more embodiments of the present invention provide applications for SDL pixels. More particularly, one or more embodiments of the present invention provide a method for providing a digital film sensor that emulates, at least to some degree, contemporary silver halide film. Embodiments described above illustrate, but do not limit, the invention. It should also be understood that numerous modifications and variations are possible in accordance with the principles of the present invention. Accordingly, the scope of the invention is defined only by the following claims.

An imaging system has an imager comprising a plurality of jots. A readout circuit is in electrical communication with the imager. The readout circuit can be configured to facilitate the formation of an image by defining neighborhoods of the jots, wherein a local density of exposed jots within a neighborhood is used to generate a digital value for a pixel of the image.

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This patent application claims the benefit of priority as a continuation of U.S. patent application Ser. No. 14/010,793 filed on Aug. 27, 2013 entitled “Methods and Systems for Delayed Notifications in Communication Networks”, currently pending, which itself claims the benefit of priority from U.S. Provisional Patent Application 61/694,325 filed on Aug. 29, 2012 entitled “Methods and Systems for Delayed Notifications in Communications Networks.” FIELD OF THE INVENTION [0002] The present invention relates to communications systems and more particularly delayed notifications and enhanced sender feedback. BACKGROUND OF THE INVENTION [0003] Communication is the exchange of thoughts, messages, or information, as by speech, visuals, signals, writing, or behavior. As such communication requires a sender, a message, and a recipient, although the receiver does need not be present or aware of the sender's intent to communicate at the time of communication and therefore communication can occur across wide ranges of distances in both time and space. Typically communication requires that the communicating parties share an area of communicative commonality and a communication process is typically considered complete once the receiver has understood the message of the sender. [0004] The first major model of communication, see Shannon et al in “The Mathematical Theory of Communication” (University of Illinois Press, 1949) consisted of three primary parts, namely sender, channel, and receiver. In a simple model, often referred to as the transmission model or standard view of communication, information or content (e.g. a message in a natural language) is sent in some form (e.g. as spoken language) from a source/sender/encoder to a destination/receiver/decoder. This common conception of communication simply views communication as a means of sending and receiving information and according to Shannon is based on the following elements: an information source, which produces a message; a transmitter, which encodes the message into signals; a channel, to which signals are adapted for transmission; a receiver, which decodes (reconstructs) the message from the signal; and a destination, where the message arrives. [0010] This model was expanded by Berlo et al into the Sender-Message-Channel-Receiver (SMCR) Model of Communication, see for example “The Process of Communication” (Rinehart & Winston Press, New York, 1960) which separated the communication model into clear parts and has been expanded upon by other scholars. Accordingly, such models allow one-way, two-way, and multi-way conversations to be modeled, analysed and implemented within telecommunications infrastructure across multiple communications technologies to perform the transmitter, channel, and receiver such as wireless, wired, and fiber optic. Such models also support multiple communication formats including, for example, voice, either through Plain Old Telephone Service (POTS) or Voice-over-Internet Protocol (VOIP), as a general two-way communication process, electronic mail, commonly referred to as email and generalized into one-way communications, and Short Message Service, commonly referred to as SMS or text and similarly generalized into a one-way communication. Accordingly, communications common today such as “Tweeting” on the social media network Twitter™ and concepts such as “email threads” and Instant Messaging are merely concatenations of multiple discrete email and SMS one-way communications. “Tweeting” and email provide multicast communications wherein the message is communicated to a plurality of recipients simultaneously in a single transmission from the source wherein copies of the message are automatically created in other network elements, such as routers, but only when the topology of the network requires it. [0011] However, these models and the consideration of the interactions between sender and recipient is that the message is sent by the sender and received by the recipient as a single process and that other aspects of the communications channel such as voicemail, email server, and text server that store the senders message prior to the recipients receipt are modeled as a delay within the communications channel. However, going back to the primary definition of communication is the exchange of thoughts, messages, or information and accordingly these models and their physical implementations do not provide for verification that the exchange has occurred in the manner the sender intended unless for example the voice communication is a two-way session or a subsequent one-way communication from the recipient referencing the original one-way communication or its content is received by the sender. [0012] According, whilst voicemail's introduction enabled people to leave lengthy, secure and detailed messages in natural voice, working hand-in-hand with corporate and personal phone systems it also broke the two-way communication session methodology of telephony prior to its introduction. This is further compounded by there being two main modes of voicemail operation, namely telephone answering and voice messaging. Telephone answering voicemail answers outside calls and takes a message from any outside caller, either because the extension was busy or rang with no-answer, or voice messaging which enables any subscriber with a mailbox number to send messages directly to any or many subscribers' mailboxes without first calling them. Accordingly, the sender is unable to determine whether the recipient has listened to the message, deleted it unheard, or stopped listening part way through the voicemail. With the rapid uptake of portable electronic devices (PEDs) many individuals now have three or more telephone numbers, for example home, cellphone, and work, thereby increasing the complexity of ensuring a message is delivered to a recipient, yet alone played and understood. [0013] These issues have continued into email and SMS/text communications in the last thirty years as these systems have proliferated. With the adoption of email into business activities and its replacement of physical mail delivery which provided options for delivery verification such as from the mail delivery organization itself or through a signature of the recipient the absence of verification presented an issue. Accordingly, some email systems such as Microsoft™ Outlook introduced email to provide a digitally time-stamped record to reveal the exact time and date that an email was received and/or opened according to the settings established by the sender. However, due to the nature of the technology, email tracking cannot be considered an absolutely accurate indicator that a message was opened or read by the recipient. Even receiving a reply referencing the original email does not address whether the recipient read the content. [0014] Likewise within SMS/text systems the vast majority of such systems, commonly referred to as Instant Messaging (IM) systems, present the same issues of whether the recipient received and read the text message. Accordingly, in these systems the receipt of a reply from the recipient may provide some indication that they received or read the message but their reply could be a coincidence. One notable exception to this is Research in Motion's Blackberry™ Messenger service which provides a delivery notification on the sender's messaging interface and a read notification when the recipient opens the message. However, this service is feasible as the entire messaging system is routed through Research in Motion's own messaging servers. [0015] In many instances the sender whilst wishing to send the recipient a message does not wish to send the message at the time they decide to do so as they do not wish to disturb the recipient or potentially disturb the recipient. For example, the sender may need to send a message to the recipient at 10 pm in the evening at their home but does not want to disturb the recipient and their family at home. Accordingly, the sender may decide not to send the message at that time and to do so in the morning wherein they may forget or miss the recipient. Alternatively they may elect to use another form of communications, such as email, which is not delivered to the recipient due to a network issue or is not seen or opened by the recipient. [0016] Accordingly it would be beneficial to provide enhancements to voicemail, email, SMS and other communications that provide additional information to the sender with respect to the delivery to and recovery by the recipient of the message such that not only do they have the option to elect to receive a delivery notification in communications systems that today do not provide such information, but that in these systems and those supporting delivery notifications increased information is provided to the user allowing them to ascertain or estimate the recipient's absorption/reading of the message. [0017] Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures. SUMMARY OF THE INVENTION [0018] It is an object of the present invention to mitigate limitations in the prior art relating to communications systems and more particularly delayed notifications and enhanced sender feedback. [0019] In accordance with an embodiment of the invention there is provided a method comprising: receiving at an electronic device a first message from a sender intended for a user of the electronic device; determining whether the user accesses the first message; initiating when a positive determination is made a first process is executed by a processor forming a predetermined portion of the electronic device, the first process for monitoring at least a first characteristic of a plurality of characteristics, each characteristic relating to the user's access of the first message; determining whether the user has finished accessing the first message; transmitting to the sender data relating to the user's accessing of the first message, the data comprising at least the first characteristic of the plurality of characteristics. [0024] In accordance with an embodiment of the invention there is provided a method comprising: a) receiving upon a first electronic device from a user a first message for transmission to a contact; b) receiving upon the first electronic device a plurality of items of contact data; c) receiving upon the first electronic device from the user time data relating to a future point in time that the first message should not be delivered before; d) transmitting the first message and user time date to a second electronic device from the first electronic device, the second electronic device associated with a first item of contact data of the plurality of items of contact data; e) receiving at the first electronic device an indication that the first message was not delivered to the second electronic device associated with the first item of contact data of the plurality of items of contact data; f) automatically transmitting to another electronic device associated with another item of contact data of the plurality of items of contact data a second message and user time data; and g) displaying on the one of the second electronic device and another electronic device to which the first message was successfully delivered an indication that the respective one of the first message and second message for the contact is available after the future point in time indicated by the user time data has passed. [0032] Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures. BRIEF DESCRIPTION OF THE DRAWINGS [0033] Embodiments of the present invention will now be described, by way of example only, with reference to the attached Figures, wherein: [0034] FIG. 1 depicts a network supporting communications to and from electronic devices implementing temporally delayed messaging according to embodiments of the invention; [0035] FIG. 2 depicts an electronic device and network access point supporting temporally delayed messaging according to embodiments of the invention; [0036] FIG. 3 depicts a network supporting communications to and from electronic devices implementing temporally delayed messaging according to embodiments of the invention; [0037] FIG. 4 depicts a process flow for a telephone message according to the prior art; [0038] FIG. 5 depicts a process flow for an electronic mail message according to the prior art; [0039] FIG. 6 depicts a process flow for a voicemail delivery system according to an embodiment of the invention; [0040] FIG. 7 depicts a process flow for a short message delivery system according to an embodiment of the invention; [0041] FIG. 8 depicts a process flow for a voicemail delivery system according to an embodiment of the invention allowing the user to modify contact delivery information upon a failed initial delivery; [0042] FIG. 9 depicts a process flow for a short message delivery system according to an embodiment of the invention allowing the user to modify contact delivery and message information upon a failed initial delivery; [0043] FIG. 10 depicts a process flow for a voicemail delivery system according to an embodiment of the invention allowing the user to modify contact delivery information upon a failed initial delivery or delayed recovery by the receiving contact; and [0044] FIG. 11 depicts a process flow for an electronic mail message system according to an embodiment of the invention allowing the user to perform actions based upon failure of recipient to open electronic mail message or review portion of contents. DETAILED DESCRIPTION [0045] The present invention is directed to communications systems and more particularly delayed notifications and enhanced sender feedback. [0046] The ensuing description provides exemplary embodiment(s) only, and is not intended to limit the scope, applicability or configuration of the disclosure. Rather, the ensuing description of the exemplary embodiment(s) will provide those skilled in the art with an enabling description for implementing an exemplary embodiment. It being understood that various changes may be made in the function and arrangement of elements without departing from the spirit and scope as set forth in the appended claims. [0047] A “portable electronic device” (PED) as used herein and throughout this disclosure, refers to a wireless device used for communication that requires a battery or other independent form of energy for power. This includes devices, but is not limited to, such as a cellular telephone, smartphone, personal digital assistant (PDA), portable computer, pager, portable multimedia player, portable gaming console, laptop computer, tablet computer, and an electronic reader. A “fixed electronic device” (FED) as used herein and throughout this disclosure, refers to a wireless device or wired device used for communication that does not require a battery or other independent form of energy for power. This includes devices, but is not limited to, Internet enable televisions, gaming systems, desktop computers, kiosks, and Internet enabled communications terminals. [0048] A “network operator/service provider” as used herein may refer to, but is not limited to, a telephone or other company that provides services for mobile phone subscribers including voice, text, and Internet; telephone or other company that provides services for subscribers including but not limited to voice, text, Voice-over-IP, and Internet; a telephone, cable or other company that provides wireless access to local area, metropolitan area, and long-haul networks for data, text, Internet, and other traffic or communication sessions; etc. [0049] A “software system” as used as used herein may refer to, but is not limited to, a server based computer system executing a software application or software suite of applications to provide one or more features relating to the licensing, annotating, publishing, generating, rendering, encrypting, social community engagement, storing, merging, and rendering electronic content and tracking of user and social community activities of electronic content. The software system being accessed through communications from a “software application” or “software applications” and providing data including, but not limited to, electronic content to the software application. A “software application” as used as used herein may refer to, but is not limited to, an application, combination of applications, or application suite in execution upon a portable electronic device or fixed electronic device to provide one or more features relating to one or more features relating to generating, rendering, managing and controlling a user interface. The software application in its various forms may form part of the operating system, be part of an application layer, or be an additional layer between the operating system and application layer. [0050] A “user” or “sender” as used herein and through this disclosure refers to, but is not limited to, a person or device that utilizes the software system and/or software application and as used herein may refer to a person, group, or organization that sends a message with the software system and/or software application. A “contact” or “recipient” or “receiver” as used herein and through this disclosure refers to, but is not limited to, a person or device that utilizes the software system and/or software application and as used herein may refer to a person, group, or organization that receives a message with the software system and/or software application. [0051] Now referring to FIG. 1 there is depicted a network 100 supporting communications to and from electronic devices implementing temporally delayed messaging according to embodiments of the invention. As shown first and second user groups 100 A and 100 B respectively interface to a telecommunications network 100 . Within the representative telecommunication architecture a remote central exchange 180 communicates with the remainder of a telecommunication service providers network via the network 100 which may include for example long-haul OC-48/OC-192 backbone elements, an OC-48 wide area network (WAN), a Passive Optical Network, and a Wireless Link. The central exchange 180 is connected via the network 100 to local, regional, and international exchanges (not shown for clarity) and therein through network 100 to first and second wireless access points (AP) 195 A and 195 B respectively which provide Wi-Fi cells for first and second user groups 100 A and 100 B respectively. Also connected to the network 100 are first and second Wi-Fi nodes 110 A and 110 B, the latter of which being coupled to network 100 via router 105 . Second Wi-Fi node 110 B is associated with residential building 160 A and environment 160 within which are first and second user groups 100 A and 100 B. Second user group 100 B may also be connected to the network 100 via wired interfaces including, but not limited to, DSL, Dial-Up, DOCSIS, Ethernet, G.hn, ISDN, MoCA, PON, and Power line communication (PLC) which may or may not be routed through a router such as router 105 . [0052] Within the cell associated with first AP 110 A the first group of users 100 A may employ a variety of portable electronic devices including for example, laptop computer 155 , portable gaming console 135 , tablet computer 140 , smartphone 150 , cellular telephone 145 as well as portable multimedia player 130 . Within the cell associated with second AP 110 B are the second group of users 100 B which may employ a variety of fixed electronic devices including for example gaming console 125 , personal computer 115 and wireless/Internet enabled television 120 as well as cable modem 105 . [0053] Also connected to the network 100 are first and second APs which provide, for example, cellular GSM (Global System for Mobile Communications) telephony services as well as 3G and 4G evolved services with enhanced data transport support. Second AP 195 B provides coverage in the exemplary embodiment to first and second user groups 100 A and 100 B. Alternatively the first and second user groups 100 A and 100 B may be geographically disparate and access the network 100 through multiple APs, not shown for clarity, distributed geographically by the network operator or operators. First AP 195 A as show provides coverage to first user group 100 A and environment 160 , which comprises second user group 100 B as well as first user group 100 A. Accordingly, the first and second user groups 100 A and 100 B may according to their particular communications interfaces communicate to the network 100 through one or more wireless communications standards such as, for example, IEEE 802.11, IEEE 802.15, IEEE 802.16, IEEE 802.20, UMTS, GSM 850, GSM 900, GSM 1800, GSM 1900, GPRS, ITU-R 5.138, ITU-R 5.150, ITU-R 5.280, and IMT-2000. It would be evident to one skilled in the art that many portable and fixed electronic devices may support multiple wireless protocols simultaneously, such that for example a user may employ GSM services such as telephony and SMS and Wi-Fi/WiMAX data transmission, VOIP and Internet access. Accordingly portable electronic devices within first user group 100 A may form associations either through standards such as IEEE 802.15 and Bluetooth as well in an ad-hoc manner. [0054] Also connected to the network 100 are retail environment 165 , first commercial environment 170 , and second commercial environment 175 as well as first and second servers 190 A and 190 B which together with others not shown for clarity, may host according to embodiments of the inventions multiple services associated with a provider of the software operating system(s) and/or software application(s) associated with the electronic device(s), a provider of the electronic device, provider of one or more aspects of wired and/or wireless communications, product databases, inventory management databases, retail pricing databases, license databases, customer databases, websites, and software applications for download to or access by fixed and portable electronic devices. First and second primary content sources 190 A and 190 B may also host for example other Internet services such as a search engine, financial services, third party applications and other Internet based services. [0055] FIG. 2 there is depicted an electronic device 204 and network access point 207 supporting temporally delayed messaging according to embodiments of the invention. Electronic device 204 may for example be a portable electronic device or a fixed electronic device and may include additional elements above and beyond those described and depicted. Also depicted within the electronic device 204 is the protocol architecture as part of a simplified functional diagram of a system 200 that includes an electronic device 204 , such as a smartphone 155 , an access point (AP) 206 , such as first Wi-Fi AP 610 , and one or more network devices 207 , such as communication servers, streaming media servers, and routers for example such as first and second servers 175 and 185 respectively. Network devices 207 may be coupled to AP 206 via any combination of networks, wired, wireless and/or optical communication links such as discussed above in respect of FIG. 1 . The electronic device 204 includes one or more processors 210 and a memory 212 coupled to processor(s) 210 . AP 206 also includes one or more processors 211 and a memory 213 coupled to processor(s) 211 . A non-exhaustive list of examples for any of processors 210 and 211 includes a central processing unit (CPU), a digital signal processor (DSP), a reduced instruction set computer (RISC), a complex instruction set computer (CISC) and the like. Furthermore, any of processors 210 and 211 may be part of application specific integrated circuits (ASICs) or may be a part of application specific standard products (ASSPs). A non-exhaustive list of examples for memories 212 and 213 includes any combination of the following semiconductor devices such as registers, latches, ROM, EEPROM, flash memory devices, non-volatile random access memory devices (NVRAM), SDRAM, DRAM, double data rate (DDR) memory devices, SRAM, universal serial bus (USB) removable memory, and the like. [0056] Electronic device 204 may include an audio input element 214 , for example a microphone, and an audio output element 216 , for example, a speaker, coupled to any of processors 210 . Electronic device 204 may include a video input element 218 , for example, a video camera, and a video output element 220 , for example an LCD display, coupled to any of processors 210 . Electronic device 204 also includes a keyboard 215 and touchpad 217 which may for example be a physical keyboard and touchpad allowing the user to enter content or select functions within one of more applications 222 . Alternatively the keyboard 215 and touchpad 217 may be predetermined regions of a touch sensitive element forming part of the display within the electronic device 204 . The one or more applications 222 that are typically stored in memory 212 and are executable by any combination of processors 210 . Electronic device 204 also includes accelerometer 260 providing three-dimensional motion input to the process 210 and GPS 262 which provides geographical location information to processor 210 . [0057] Electronic device 204 includes a protocol stack 224 and AP 206 includes a communication stack 225 . Within system 200 protocol stack 224 is shown as IEEE 802.11 protocol stack but alternatively may exploit other protocol stacks such as an Internet Engineering Task Force (IETF) multimedia protocol stack for example. Likewise AP stack 225 exploits a protocol stack but is not expanded for clarity. Elements of protocol stack 224 and AP stack 225 may be implemented in any combination of software, firmware and/or hardware. Protocol stack 224 includes an IEEE 802.11-compatible PHY module 226 that is coupled to one or more Front-End Tx/Rx & Antenna 228 , an IEEE 802.11-compatible MAC module 230 coupled to an IEEE 802.2-compatible LLC module 232 . Protocol stack 224 includes a network layer IP module 234 , a transport layer User Datagram Protocol (UDP) module 236 and a transport layer Transmission Control Protocol (TCP) module 238 . [0058] Protocol stack 224 also includes a session layer Real Time Transport Protocol (RTP) module 240 , a Session Announcement Protocol (SAP) module 242 , a Session Initiation Protocol (SIP) module 244 and a Real Time Streaming Protocol (RTSP) module 246 . Protocol stack 224 includes a presentation layer media negotiation module 248 , a call control module 250 , one or more audio codecs 252 and one or more video codecs 254 . Applications 222 may be able to create maintain and/or terminate communication sessions with any of devices 207 by way of AP 206 . Typically, applications 222 may activate any of the SAP, SIP, RTSP, media negotiation and call control modules for that purpose. Typically, information may propagate from the SAP, SIP, RTSP, media negotiation and call control modules to PHY module 226 through TCP module 238 , IP module 234 , LLC module 232 and MAC module 230 . [0059] It would be apparent to one skilled in the art that elements of the electronic device 204 may also be implemented within the AP 206 including but not limited to one or more elements of the protocol stack 224 , including for example an IEEE 802.11-compatible PHY module, an IEEE 802.11-compatible MAC module, and an IEEE 802.2-compatible LLC module 232 . The AP 206 may additionally include a network layer IP module, a transport layer User Datagram Protocol (UDP) module and a transport layer Transmission Control Protocol (TCP) module as well as a session layer Real Time Transport Protocol (RTP) module, a Session Announcement Protocol (SAP) module, a Session Initiation Protocol (SIP) module and a Real Time Streaming Protocol (RTSP) module, media negotiation module, and a call control module. [0060] Portable and fixed electronic devices represented by electronic device 204 may include one or more additional wireless or wired interfaces in addition to the depicted IEEE 802.11 interface which may be selected from the group comprising IEEE 802.15, IEEE 802.16, IEEE 802.20, UMTS, GSM 850, GSM 900, GSM 1800, GSM 1900, GPRS, ITU-R 5.138, ITU-R 5.150, ITU-R 5.280, IMT-2000, DSL, Dial-Up, DOCSIS, Ethernet, G.hn, ISDN, MoCA, PON, and Power line communication (PLC). [0061] FIG. 3 depicts a 2G/3G network 300 supporting communications to and from electronic devices implementing temporally delayed messaging according to embodiments of the invention. As depicted 2G/3G network 300 comprises multiple elements described supra in respect of FIG. 1 such as a portion of network 100 , remote central exchange 180 , and first and second wireless access points (AP) 195 A and 195 B respectively. However, 2G/3G network 300 depicts that predetermined portion of network 100 in particular and in more detail that relates to the wireless support for FEDs and PEDs. 2G/3G network 300 supports so-called 2G (second generation) wireless telephone technology standards such as GSM (Global System for Mobile Communications, originally Groupe Special Mobile) implemented in GSM 850 MHz, GSM 900 MHz, GSM 1800 MHz, and GSM 1900 MHz exploiting primarily TDMA (Time Division Multiple Access). 2G/3G network 300 also supports other 2G/3G (third generation) wireless telephone technology standards such as GPRS (General Packet Radio Service) and 3G standards such as UMTS (Universal Mobile Telecommunications System). Whilst 4G (fourth generation) wireless telephone technology standards are not discussed in respect of 2G/3G network 300 it would be evident to one skilled in the art that such standards as IMT-2000 and IMT-Advanced ((International Mobile Telecommunications) embodied in LTE-Advanced (Long-Term Evolution Advanced), IEEE 802.16m (WirelessMAN), 3GPP (3G Partnership Project) LTE and IEEE 802.16e (Mobile WiMAX) may also be supported through variations in the 2G/3G network 300 elements, additional infrastructure, and software/firmware for example. As depicted a 3G UMTS cell 305 is addressed by Node 305 A, for example such as described supra in respect of first and second wireless access points (AP) 195 A and 195 B respectively in FIG. 1 , providing UMTS services to users connected to the UMTS cell 305 from their FEDs/PEDs. Node 305 A communicates with a Radio Network Controller (RNC) 310 which is then in communication with Mobile Switching Center (MSC) 325 and Serving GPRS Support Node (SGSN) 335 . [0062] Also depicted is GSM cell 315 addressed by Base Transceiver Station (BTS) 315 A, for example such as described supra in respect of first and second wireless access points (AP) 195 A and 195 B respectively in FIG. 1 , providing GSM services to users connected to the GSM cell 315 via their FEDs/PEDs. The BTS 315 A is similarly in communication with the MSC 325 and SGSN 335 respectively as is Node 305 A and these are also coupled to one another via direct communications link and Equipment Identity Register (EIR) 385 which maintains a database with records of all the mobile stations (MS) that are allowed in a network as well as a database of all equipment that is banned, e.g. because it is lost or stolen for example. Accordingly, FEDs/PEDs registering with one or other of the UMTS and/or GSM networks are registered into the EIR 385 and validated. Also coupled to MSC 325 are a Private Automatic Branch eXchange (PABX) 330 , denoting an exchange serving a particular business or enterprise as opposed to one operated by a telecom carrier that operates for many businesses or for the general public, and an IN Database 380 used in conjunction with an Intelligent Network Application Part (INAP) signaling protocol used for controlling telecommunication services migrated from traditional switching points to computer based service independent platforms such as for example 0800 free phone access. [0063] MSC 325 and SGSN 335 also communicate with Home Location Register (HLR) 390 which provides a central database containing details of each subscriber authorized to use the core network. HLR 390 also communicates with Gateway GPRS Support Node (GGSN) 355 which provides a gateway interconnection between the packet mobile networks, e.g. GPRS, GSM, and UMTS, and the public data network (Internet) 370 . Accordingly, a user accessing their PED in GSM cell 315 has their communications routed through BSC 320 , SGSN 335 via Private Backbone 350 to GGSN 355 and therein the Internet 370 . The device and account verification for a user is performed through the polling of EIR 385 and HLR 390 . Verification through HLR 390 also invokes Authentication Centre (AUC) 395 which authenticates each SIM card that attempts to connect to the network thereby allowing the HLR 390 to manage the SIM and services. This authentication also includes, typically, generation of an encryption key which is subsequently used to encrypt all wireless communications, such as voice and Simple Message Service (SMS) for example, between the mobile phone and the GSM core network. [0064] Also connected to the Private Backbone 350 is GPRS Roaming Exchange (GRX) which acts as a hub for GPRS connections from roaming users thereby removing the need for dedicated link between each GPRS service provider and hence between multiple 2G/3G networks 300 . The MSC 325 as depicted is also coupled to Short Message Service Center (SM-SC) 360 such that SMS messages send by users are stored within the SM-SC 360 which delivers each SMS message to its destination user when they are available, i.e. when they access via UMTS 305 or GSM 315 for example and their presence is determined through the verification and authentication processes with EIR 385 , HLR 290 , and AUC 395 which are accessible by SM-SC 360 via MSC 325 . Also connected to the MSC 325 is Gateway Mobile Switching Center (GMSC) which determines which visited MSC the subscriber being called is currently located as well as routing all communications to/from PEDs and the Public Switched Telephone Network (PSTN)/Integrated Services Digital Network (ISDN) 375 which handles services including Plain Old Telephony Service (POTS) as well as simultaneous digital transmission of voice, video, data, and other network services over the traditional circuits such as copper wire. Accordingly such a 2G/3G network 300 [0065] FIG. 4 depicts a process flow 400 for a telephone message according to the prior art. Process flow 400 starts at step 405 and proceeds to step 410 wherein a user decides to contact a contact and dials their phone number wherein the telecommunications system, such as described above in respect of FIGS. 1 and 3 , interfaced to their device, such as for example PED 204 in FIG. 2 , attempts to establish a connection to the contact's phone, which may be for example a FED on a fixed land line, a FED with wireless interface, a PED with wireless interface or a FED on a Voice-over-Internet Protocol (VOIP) service over a wired interface. In step 420 if the system is unable to establish a connection to the contact's phone, such as for example due to a capacity issue on a link within the network, a switching node capacity issue or blocked path, then the process flow proceeds to step 425 wherein the telecommunication system provides an engaged tone to the user and the flow proceeds to step 455 and stops. Alternatively at step 420 if a connection is established the process proceeds to step 430 wherein the process flow forks according to whether the contact answers or not. If the contact answers the process flow 400 proceeds to step 435 with the user and contact engaging resulting in the user's message being delivered in step 440 wherein at the completion of the conversation the process flow 400 proceeds to step 455 and stops. If the contact does not answer the process flow 400 proceeds to step 445 with the user hearing a longer ring tone followed by the process flow 400 transferring to a voicemail system wherein the user has the option to lead a voicemail wherein the process proceeds to step 460 or not leave a message wherein the process proceeds to step 455 and stops. [0066] Where the user decides to leave a voicemail then in step 460 the user leaves the voicemail message wherein the process proceeds to step 465 and provides an indication to the user that a voicemail message is available for them. Next in step 470 the process essentially holds pending a decision of the contact to play the voicemail message wherein the process plays back the message in step 475 when the user has elected to hear the message wherein the process proceeds to step 455 and stops. It would be evident to one skilled in the art that the contact, according to the particular characteristics of the voicemail system, may delete the voicemail unheard, delete the voicemail after hearing a short initial portion, or be unaware that this particular voicemail is awaiting as there other voicemails already stored and the system merely indicates messages waiting or indicates just a number of messages waiting. [0067] Now referring to FIG. 5 there is depicted a process flow 500 for an electronic mail (email) message according to the prior art. The process begins at step 505 and proceeds to step 510 wherein a user decides to send an email to a contact. Accordingly, in process step 515 the email software system stores the email generated by the user for the contact within memory. Next in step 520 the user decides whether to send the email immediately or at a later point in time wherein if the decision is to not delay the process proceeds to step 525 and the email is sent from the user's email system to the contact's email server. If the decision in step 520 is to delay sending the email then process proceeds to step 530 wherein the user enters the time after which the email should be sent from their email system. The process then proceeds to step 535 wherein the user's email system stores the email until the time selected by the user wherein it then the process proceeds to step 525 and sends the email to the email server of the contact. [0068] In step 540 a determination is made whether the email was delivered to the contact's email system wherein a negative determination results in the process proceeding to step 545 such that a delivery failure notice to the user's email account is sent and the process proceeds to step 580 and stops. Optionally, the user's email system only provides a delivery failure notice if the user elects to select this option and accordingly in some embodiments of the invention the process would therefore proceed directly from process step 540 to process step 580 . If the determination at step 540 was positive then the process proceeds to step 550 wherein the contact at a subsequent point in time accesses their email system wherein in step 555 the email system displays the InBox to the contact which would now include the email message from the user with an appropriate indication that the email message is new. The process then proceeds to step 560 which is essentially depicts a hold as no further action arises unless the contact opens the email message from the user. If the contact opens the email message from the user then the process proceeds to step 565 wherein a determination is made as to whether the user requested a read receipt for the email message. If the determination is positive then the process proceeds to step 570 wherein an email is sent to the user indicating that the contact has opened the email and the process proceeds to step 575 wherein the email is displayed to the contact, otherwise the process proceeds to step 575 directly. Accordingly the process then proceeds to step 580 and ends. [0069] It would be evident to one skilled in the art that a contact opening an email does not automatically mean that they actually read the email and that other actions such as reading part of the email message contents, the contact deleting the email message, or the email message being transferred to a “junk” or “spam” folder may occur that result in the user not receiving notice that the contact has opened and reviewed the email or understood the message. In some email systems the contact is provided with a pop-up window indicating that a read receipt has been requested and provides options to the contact to either send such a receipt or not send it. [0070] Accordingly, it would be beneficial in many instances where email messages and/or voicemail messages are sent containing time sensitive information, as well as other electronic communications such as SMS messages (text messages or texts), that the contact is aware as to whether the message has been received, that the pertinent information is read, and the contact can undertake other actions should they be required due to the nature of the contents of the message sent to the contact. In other situations a user may decide to send a message to a contact on the basis that they do not wish to have the contact receive the message immediately. For example, a user may decide to leave a message at a time that they know or suspect is inconvenient for the contact or at a time they do not wish to disturb the contact. Examples of such instances may include, but not limited to, middle of the night, very early in the morning and evening. Equally, the embodiments of the invention in addition to providing these benefits allow for timed messaging to be established as part of a marketing campaign or other business related activity. For example, an enterprise may establish a SMS release to a predetermined client group offering a limited time offer and verify the clients who actually opened the message within the time limit whilst allowing redemption upon a different time frame. It would be evident to one skilled in the art that other applications exist exploiting such time and verification based messaging. [0071] Now referring to FIG. 6 there is depicted a process flow 600 for a voicemail delivery system according to an embodiment of the invention. The process begins at step 605 A and proceeds to step 610 wherein a user decides to send a voicemail to a contact on the basis that they do not wish to have the contact receive the message immediately and also to know that the contact has received the content within the message. Accordingly, in process step 615 the voicemail software system allows the user to generate a voicemail for a contact at a contact number wherein the software system stores the voicemail generated by the user for the contact within memory. Next in step 620 the user enters the later point in time that they wish the voicemail message to be provided to the contact wherein voicemail message and timing information are transferred in step 625 from the voicemail system to a remote system wherein it is stored in step 630 until the indicated time has passed at which point it is sent to the contact number of the contact provided by the user in generating the voicemail. [0072] The process then proceeds to step 635 wherein a determination is made as to whether the voicemail was delivered to the contact's voice inbox or not. If not, then the process flow 600 proceeds to step 640 wherein a delivery failure notice is provided to the user and the process proceeds to step 605 B and stops. Upon successful delivery of the voicemail to the contact's voice inbox the process flow proceeds to step 650 and an indication of a voicemail is provided to the contact on the device or devices associated with their voice inbox. Subsequently the contact in step 655 accesses their voicemail system and a determination is made in step 660 as to whether the contact recovered the voicemail. If that determination is negative then the process loops back to step 650 so that an indication of un-played voicemails is provided to the contact. If it is positive then the process proceeds to step 665 wherein it is determined whether a read receipt for the voicemail has been requested by the user in generating the voicemail. If not then the process proceeds to step 670 wherein the contact listens to that portion of the voicemail message that they decide to and the process proceeds to a second decision in step 680 on the read receipt which results in the process proceeding to step 695 wherein a first status message is sent to the user indicating that the contact did at least “open” the voicemail. [0073] Alternatively, the process proceeds from step 665 to step 670 wherein a timer is initiated with respect to the contact listening to the message in step 675 . Accordingly, after the contact has stopped listening to the voicemail message the second decision in step 680 directs the process flow to step 685 wherein listening statistics relating to the voicemail playback by the contact are calculated. For example this may be length of message, length of message played back, and percentage of message listened to. From step 685 the process proceeds to terminate in step 605 B via process step 690 where the user who sent the message is sent a message containing the listening statistics as part of the message indicating the contact played the voicemail. Accordingly, the user may ascertain how much of the message the contact listened to and based upon knowledge of the voicemail they generated whether the contact played the portion containing the important core element of their message. [0074] Optionally, as there may be a significant delay between step 635 wherein there is a determination that the message has been delivered to the contact's voice inbox and steps 690 and 695 , wherein a message is provided to the user that the contact has played the voicemail with or without call statistics, an additional message may be provided between steps 635 and 650 to indicate to the user that the message has been delivered successfully to the contact. [0075] Now referring to FIG. 7 there is depicted a process flow 700 for a short message (commonly known as SMS message or text) delivery system according to an embodiment of the invention. Process flow 700 comprises process steps 705 A through 795 which essentially mirror the process flow 600 described above in respect of FIG. 6 with the amendments that rather than a voicemail message the content is a text message, that the text message is delivered to the contact's text messaging system rather than their voicemail system and the determination of statistics is based upon how long the user has the text message open and hence assumed to be reading it. Accordingly, a read receipt request results in the user having information relating to the contact's action with the text message. [0076] It would evident that more complex processing of the contact's actions may be undertaken, such as for example, one where in addition to the time of the contact having the text message open it contains information relating to did the user scroll through the message, if so what portion of the message did they scroll through, did they reply to the text message, forward the text message, or delete the text message. Statistics or determinations of actions in respect of scrolling would be based for example based upon knowledge of the length of the message, did it contain image contents, what font does the contact display texts at, what are the display dimensions of the device upon which the user read the text message. [0077] It would be evident in respect of FIGS. 6 and 7 that the read receipt request, processing, and reply messaging may be implemented with multiple levels such as none, read receipt, and read statistics wherein the “none” results in no message being delivered back to the user, “read receipt” results in just a message that the text message was opened, and “read statistics” results in a read receipt that contains statistics based upon the contact's actions once the text message has been opened. [0078] Now referring to FIG. 8 there is depicted a process flow 800 for a voicemail delivery system according to an embodiment of the invention allowing the user to modify contact delivery information upon a failed initial delivery. Accordingly, as shown in process steps 805 through 825 the user proceeds in a manner essentially the same as that described in respect of steps 610 through 630 respectively in FIG. 6 in that the user decides to send a voicemail to a contact, enters the time after which the voicemail message should be delivered, and the voicemail is transferred to a remote system for storage until the predetermined time set by the user has elapsed. However, the user the also establishes a second time limit relating to a subsequent time after delivery wherein the user wishes to know whether the contact retrieved the message or not. Subsequently a determination is made in step 835 as to whether the voicemail message has been delivered to the contact's voice mailbox resulting in the process proceeding to step 840 if a positive determination is made and the system displays an indication of the voicemail message to the contact and proceeds to step 865 A if a negative determination is made wherein a voicemail failure notice #1 is sent to the user. [0079] If a positive determination was made then after step 840 the process determines in step 845 whether the contact has recovered the voicemail wherein if a negative determination is made the process proceeds to step 860 and a determination is made as to whether the time limit set by the user in respect of the contact recovering the voicemail message has been exceeded. A positive determination results in the process proceeding to step 865 B and a voicemail failure notice #2 is sent to the user indicating that the message was delivered but the predetermined limit set by the user has expired. If in step 845 the determination was that the contact had recovered the voicemail message then the process proceeds to first sub-process block 850 which comprises a series of process steps similar to those described above in respect of FIG. 6 and process steps 670 through 695 in determining whether read receipts and contact recovery statistics are required. Upon completion of first sub-process block 850 the process proceeds to step 855 and stops. [0080] For either of process steps 865 A and 865 B the process proceeds to step 870 wherein a determination is made as to whether alternate contact information is to be entered by the user. If a negative determination is made the process proceeds to step 875 and stops, otherwise a positive determination results in the process proceeding to step 880 wherein the user enters alternate contact data, such as for example changing a contact's PED number to their home telephone number. Subsequently the process flow 800 proceeds to second sub-process block 885 which comprises essentially the same process steps and logical determinations as discussed supra in respect of process steps 835 through 850 , 860 and 865 . A repeat failure of the contact to recover the voicemail or failure to deliver the voicemail results in the process flow 800 returning to process step 870 . [0081] It would be evident that according to another embodiment of the invention the determination in step 870 regarding alternate contact data for the contact may be made based upon information entered by the user during initial process steps 805 through 825 respectively wherein the user enters multiple alternate contact data and the process flow 800 sequentially tries each contact number for the contact. Optionally, the time limit post-delivery of each voicemail message to an alternate number may be varied. [0082] Optionally, as there may be a significant delay between step 835 , wherein there is a determination that the message has been delivered to the contact's voice inbox, and steps 860 and 865 B, wherein a message is provided to the user upon failure of the contact to recover the text message within the time limit set that the contact has not played the voicemail, then an additional message may be provided between steps 835 and 840 to indicate to the user whether the message has been delivered successfully to the contact. Accordingly, the user may determine upon receipt of such a message to initiate a message via an alternate means such as described in respect of FIGS. 6-7 and FIGS. 9-11 . [0083] Referring to FIG. 9 there is depicted a process flow 900 for a short message delivery system according to an embodiment of the invention allowing the user to modify contact delivery and message information upon a failed initial delivery. Process flow 900 begins with first sub-process 905 which with the exception of “Stop” process step 875 is process flow 800 described above in respect of FIG. 8 . Rather instead of progressing to “Stop” process step 875 the process flow 900 proceeds to step 910 wherein the user receives notice that the message has not been delivered. At this point the process flow 900 proceeds through a series of determinations with the user in steps 915 , 925 , 935 , and 945 wherein the user is given options to re-try without any modifications, modify primary contact data, modify secondary contact data and modify the message respectively. Process steps 925 , 935 and 945 upon positive determinations result in the process flow proceeding to steps 930 , 940 , and 950 respectively wherein the user may enter modifications to the primary contact data, secondary contact data and the message respectively. Accordingly either directly from step 945 or step 950 process flow 900 proceeds to second sub-process 960 which is similar to first sub-process 905 , and accordingly process flow 800 described above in respect of FIG. 8 with the exception of “Stop” process step 875 which is now depicted as process step 955 . [0084] Accordingly, a user may seek delayed delivery of an initial voicemail but upon failure of the initial voicemail the user is provided with the ability to re-send to alternate primary contact data, e.g. first delivery address for the message, adjust secondary contact data which if none was provided initially allows for it to be added and adjust the content of the message. For example a user may send a colleague a message regarding a meeting the next morning but does not wish to disturb the colleagues evening and hence establishes a delay such that the message will be delivered at 7 am to the colleagues PED with a time limit of 45 minutes. Whilst the message is delivered the colleague does not retrieve it such that the user upon receiving the notification to this effect modifies the primary data to ring the colleague's residential phone intending this to result in the message now being communicated to the colleague. [0085] Now referring to FIG. 10 there is depicted a process flow 1000 for a voicemail delivery system according to an embodiment of the invention allowing the user to modify contact delivery information upon a failed initial delivery or delayed recovery by the receiving contact. As depicted process steps 1010 through 1025 provide a sequence wherein a user elects to send a voicemail to a contact, generates the voicemail, enters data relating to when the voicemail should be delivered and time limit for recovery, after which the voicemail message is sent to the remote system. From process step 1025 process flow 1000 proceeds to step 1030 wherein a determination as to the delivery of the voicemail is determined. A positive determination results in process flow 1000 proceeding to first sub-process 1040 , which is the same as second sub-process block 885 in process flow 800 as described supra in respect of FIG. 8 , thereby providing for monitoring of contact's playback and determination of voicemail playback statistics. Accordingly, first sub-process 1040 either stops internally with a stop process step as discussed previously or process flow 1000 proceeds to step 1050 wherein the contact failed to retrieve a successfully delivered voicemail within the predetermined time limit set by the user and a message is delivered to the user to this effect. Process flow 1000 then proceeds to second sub-process 1055 which depicts an equivalent process sequence as process steps 910 to 950 respectively as described supra in respect of FIG. 9 . Second sub-process 1055 either stops internally or process flow 1000 returns to process step 1025 with the delivery of a modified voicemail message to the contact. [0086] If the determination in process step 1030 was that the message had not been delivered then the process proceeds to step 1035 wherein it is determined whether the delivery failed or whether another issue exists in which case the process loops back to step 1030 . A verified failed delivery results in process flow 1000 proceeding to step 1045 wherein the user is notified of the failure and the process then proceeds to second sub-process 1055 as described supra. [0087] FIG. 11 depicts an electronic mail message system according to an embodiment of the invention allowing the user to perform actions based upon failure of recipient to open electronic mail message or review portion contents. According the process begins within a start step in first sub-process 1110 which provides a process flow comparable to that described in respect of process flow 500 except that an additional link “A” is provided to the equivalent process step as step 540 and that process step 560 relating to the loop for contact recovery of the email is now replaced by process steps 1120 and 1130 . Accordingly, first sub-process 1110 proceeds with a user generating an email for a contact and upon its successful delivery to the contact and display to the contact in their email inbox wherein the process proceeds to step 1120 wherein the process determines whether the user has initiated advanced settings or not. A negative determination results in the process flow 1110 proceeding to step 1130 wherein the process loops checking for whether the contact access the email wherein a positive determination returns process flow 1100 to first sub-process 1110 at the equivalent step to step 565 in process flow 500 . [0088] If a positive determination in step 1120 is made the process proceeds to step 1140 wherein the process loops through process step 1150 until either the time limit is reached or the contact makes another email related action, such as deleting it for example, wherein in either even the process proceeds to second sub-flow 1160 which is equivalent to second sub-process 1055 in FIG. 10 which depicts an equivalent process sequence as process steps 910 to 950 respectively as described supra in respect of FIG. 9 . [0089] It would be evident to one skilled in the art that within embodiments of the invention the generation of for example a voicemail may be undertaken as a process wherein the user generates a written message which is then converted to a voicemail message or that a voice message may be converted to a text, SMS, or email message for example according to preferences of the user. It would be further evident that such conversions may also occur at the contact side as a result of preferences of the contact. Such occurrences may for example allow for a disability of the user and/or contact or relate to aspects of the FED/PED upon which the communication is sent and/or received. [0090] It would be evident that the storage of messages prior to delivery to the user may be performed on the contacts PED/FED such that delivery to their PED/FED is achieved but actually delivery notification to the contact is not performed until the allotted time set by the user. [0091] It would be evident to one skilled in the art that the embodiments of the invention relate to systems providing for the generation and reception of messages in one or more formats, including but not limited to, email, SMS, text, and voicemail. Such embodiments of the invention are essentially independent of the network over which the messages are communication and hence may include one or more additional wireless or wired interfaces/elements operating according to one or more standards which may be selected from the group comprising IEEE 802.11, IEEE 802.15, IEEE 802.16, IEEE 802.20, UMTS, GSM 850, GSM 900, GSM 1800, GSM 1900, GPRS, ITU-R 5.138, ITU-R 5.150, ITU-R 5.280, IMT-2000, DSL, Dial-Up, DOCSIS, Ethernet, G.hn, ISDN, MoCA, PON, Power line communication (PLC), and Cable TV. Wired interfaces may be further one or more of twisted-pair copper, coaxial cable, singlemode fiber optic and multimode fiber optic. [0092] It would be evident therefore be evident that embodiments of the invention may be implemented as part of existing or future communications systems and the software upon their associated PEDs/FEDs or that they be implemented as one or more standard alone software applications that may also be employed on electronic devices. It would also be evident that such software applications installed and/or operating on the electronic devices may communicate to a software system in execution upon remote servers such that communications relating to applications for the user are parsed by the remote server based software system so that notifications can be provided to the user. [0093] It would be evident to one skilled in the art that the concepts discussed above in respect of software applications and communications whilst being primarily considered from the viewpoints of tablet computers, smart phones, laptop computers and similar communications based portable electronic devices that the underlying principles may be applied to a wider variety of devices including for example portable gaming consoles, such as Nintendo DS and Sony PSP; portable music players such as Apple iPod, and eReaders such as Kobo, Kindle, and Sony Reader. It would also be evident that whilst the embodiments of the invention have been described with respect to a standalone application that they may also be employed within software applications that form part of an operating environment such as Windows, Mac OS, Linux and Android for example. [0094] It would be further evident that the messages to/from the receiver's PED/FED and from/to the sender's PED/FED may be transmitted through a remote server executing a software system and/or software application according to an embodiment of the invention wherein activities such as determining characteristics of the message send to the contact, receiving data relating to the contact's accessing of the message, and determining analytics of the message relating to the contact's access of the message may be performed by the remote system rather than at the end point PEDs/FEDs of the user and contact. [0095] Specific details are given in the above description to provide a thorough understanding of the embodiments. However, it is understood that the embodiments may be practiced without these specific details. For example, circuits may be shown in block diagrams in order not to obscure the embodiments in unnecessary detail. In other instances, well-known circuits, processes, algorithms, structures, and techniques may be shown without unnecessary detail in order to avoid obscuring the embodiments. [0096] Implementation of the techniques, blocks, steps and means described above may be done in various ways. For example, these techniques, blocks, steps and means may be implemented in hardware, software, or a combination thereof. For a hardware implementation, the processing units may be implemented within one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, micro-controllers, microprocessors, other electronic units designed to perform the functions described above and/or a combination thereof. [0097] Also, it is noted that the embodiments may be described as a process which is depicted as a flowchart, a flow diagram, a data flow diagram, a structure diagram, or a block diagram. Although a flowchart may describe the operations as a sequential process, many of the operations can be performed in parallel or concurrently. In addition, the order of the operations may be rearranged. A process is terminated when its operations are completed, but could have additional steps not included in the figure. A process may correspond to a method, a function, a procedure, a subroutine, a subprogram, etc. When a process corresponds to a function, its termination corresponds to a return of the function to the calling function or the main function. [0098] Furthermore, embodiments may be implemented by hardware, software, scripting languages, firmware, middleware, microcode, hardware description languages and/or any combination thereof. When implemented in software, firmware, middleware, scripting language and/or microcode, the program code or code segments to perform the necessary tasks may be stored in a machine readable medium, such as a storage medium. A code segment or machine-executable instruction may represent a procedure, a function, a subprogram, a program, a routine, a subroutine, a module, a software package, a script, a class, or any combination of instructions, data structures and/or program statements. A code segment may be coupled to another code segment or a hardware circuit by passing and/or receiving information, data, arguments, parameters and/or memory contents. Information, arguments, parameters, data, etc. may be passed, forwarded, or transmitted via any suitable means including memory sharing, message passing, token passing, network transmission, etc. [0099] For a firmware and/or software implementation, the methodologies may be implemented with modules (e.g., procedures, functions, and so on) that perform the functions described herein. Any machine-readable medium tangibly embodying instructions may be used in implementing the methodologies described herein. For example, software codes may be stored in a memory. Memory may be implemented within the processor or external to the processor and may vary in implementation where the memory is employed in storing software codes for subsequent execution to that when the memory is employed in executing the software codes. As used herein the term “memory” refers to any type of long term, short term, volatile, nonvolatile, or other storage medium and is not to be limited to any particular type of memory or number of memories, or type of media upon which memory is stored. [0100] Moreover, as disclosed herein, the term “storage medium” may represent one or more devices for storing data, including read only memory (ROM), random access memory (RAM), magnetic RAM, core memory, magnetic disk storage mediums, optical storage mediums, flash memory devices and/or other machine readable mediums for storing information. The term “machine-readable medium” includes, but is not limited to portable or fixed storage devices, optical storage devices, wireless channels and/or various other mediums capable of storing, containing or carrying instruction(s) and/or data. [0101] The methodologies described herein are, in one or more embodiments, performable by a machine which includes one or more processors that accept code segments containing instructions. For any of the methods described herein, when the instructions are executed by the machine, the machine performs the method. Any machine capable of executing a set of instructions (sequential or otherwise) that specify actions to be taken by that machine are included. Thus, a typical machine may be exemplified by a typical processing system that includes one or more processors. Each processor may include one or more of a CPU, a graphics-processing unit, and a programmable DSP unit. The processing system further may include a memory subsystem including main RAM and/or a static RAM, and/or ROM. A bus subsystem may be included for communicating between the components. If the processing system requires a display, such a display may be included, e.g., a liquid crystal display (LCD). If manual data entry is required, the processing system also includes an input device such as one or more of an alphanumeric input unit such as a keyboard, a pointing control device such as a mouse, and so forth. [0102] The memory includes machine-readable code segments (e.g. software or software code) including instructions for performing, when executed by the processing system, one of more of the methods described herein. The software may reside entirely in the memory, or may also reside, completely or at least partially, within the RAM and/or within the processor during execution thereof by the computer system. Thus, the memory and the processor also constitute a system comprising machine-readable code. [0103] In alternative embodiments, the machine operates as a standalone device or may be connected, e.g., networked to other machines, in a networked deployment, the machine may operate in the capacity of a server or a client machine in server-client network environment, or as a peer machine in a peer-to-peer or distributed network environment. The machine may be, for example, a computer, a server, a cluster of servers, a cluster of computers, a web appliance, a distributed computing environment, a cloud computing environment, or any machine capable of executing a set of instructions (sequential or otherwise) that specify actions to be taken by that machine. The term “machine” may also be taken to include any collection of machines that individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies discussed herein. [0104] The foregoing disclosure of the exemplary embodiments of the present invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many variations and modifications of the embodiments described herein will be apparent to one of ordinary skill in the art in light of the above disclosure. The scope of the invention is to be defined only by the claims appended hereto, and by their equivalents. [0105] Further, in describing representative embodiments of the present invention, the specification may have presented the method and/or process of the present invention as a particular sequence of steps. However, to the extent that the method or process does not rely on the particular order of steps set forth herein, the method or process should not be limited to the particular sequence of steps described. As one of ordinary skill in the art would appreciate, other sequences of steps may be possible. Therefore, the particular order of the steps set forth in the specification should not be construed as limitations on the claims. In addition, the claims directed to the method and/or process of the present invention should not be limited to the performance of their steps in the order written, and one skilled in the art can readily appreciate that the sequences may be varied and still remain within the spirit and scope of the present invention.

Communications is the exchange of thoughts, messages, or information. However, whilst immense investments into evolving communications infrastructure supporting multiple communications channels have been made the vast majority of communications models, standards, and developments focus to the transmission of the message as a single process with other aspects of the communications channel are considered simply delays in the communications channel. However, it would be beneficial to provide enhancements to such communications channels to provide additional information to the sender with respect to the delivery to and recovery by the recipient of the message such that not only do they have the option to elect to receive a delivery notification in communications systems that today do not provide such information, but that in these systems and those supporting delivery notifications increased information is provided to the user allowing them to ascertain or estimate the recipient's absorption/reading of the message.

BACKGROUND OF THE INVENTION The present invention relates to the digital image processing arts. In particular, it relates to enhancement of digital image data, and a method and apparatus for controlling overshoot in the chrominance channel when edge enhancement operations are performed. Thus, the present invention provides a method and apparatus for reducing color fringing due to edge enhancement operations without compromising resulting edge sharpness. A main advantage of digital image reproduction relative to traditional light-lens image reproduction resides in the ability to process the digital image data so as to enhance the appearance of the final output image. For example, digital filtering is often performed to sharpen edges and fine lines for purposes of making an output image more visually appealing. When reducing or scaling-down an image, pre-filtering is often performed prior to sub-sampling for purposes of anti-aliasing. Due to limitations of the filtering algorithm, this filtering operation can blur an image. Also, in color image reproduction, it is a common practice to sub-sample the chrominance information to reduce the number of bits necessary to represent an image. This, too, can result in blurred edges. In either case and others, edge enhancement of the filtered image can be performed to sharpen the final output image. One drawback associated with conventional edge enhancement operations is that the chrominance information can be altered significantly from its original value so that the color of the final output image is altered compared to the original image. This “color fringing” is, obviously, undesirable and must be controlled in order to provide an aesthetically pleasing final image. Heretofore, no effective method and apparatus have been provided for controlling chrominance channel overshoot due to image enhancement operations without compromising edge sharpness. SUMMARY OF THE INVENTION In accordance with the present invention, a new and improved method and apparatus are provided for chrominance channel overshoot control in image enhancement operations. In accordance with a first aspect of the present invention, a method of digital image processing comprises receiving input digital image data defining a plurality of pixels of an input color digital image, the input digital image data including at least a first input chrominance value for each of the pixels of the input image. For each of the pixels of the input digital image, the input digital image data defining the pixel is enhanced based upon the input digital image data defining neighborhood pixels in a spatial neighborhood established about the pixel to obtain enhanced digital image data defining the pixel, the enhanced digital image data including at least a first enhanced chrominance value. For each of the pixels of the input digital image, an overshoot control operation is performed on the enhanced digital image data defining the pixel, the overshoot control operation including: determining first local maximum and first local minimum first input chrominance values in a neighborhood about the pixel; comparing the first enhanced chrominance value to the first local maximum and first local minimum chrominance values to determine if the first enhanced pixel chrominance value is one of: (i) above the first local maximum chrominance value by a first overshoot amount; and, (ii) below the first local minimum chrominance value by a first overshoot amount; if the first enhanced chrominance value of the pixel is above the first local maximum chrominance value, reducing the first enhanced chrominance value to reduce the first overshoot amount; and, if the first enhanced chrominance value of the pixel is below the first local minimum chrominance value, increasing the first enhanced chrominance value to reduce the first overshoot amount. In accordance with another aspect of the present invention, a method of enhancing a color digital image includes, for each of a plurality of pixels defining the color digital image, modifying a first chrominance value of a pixel in response to an enhancement filtering operation to obtain a modified first chrominance value for the pixel. Within a neighborhood of pixels spatially near the pixel, identifying a local minimum and a local maximum first chrominance value of the pixels within the neighborhood. The modified first chrominance value is compared to at least one of the local minimum and local maximum first chrominance values and, if the modified first chrominance value is greater than the local maximum first chrominance value, the modified first chrominance value of the pixel is reduced by a select percentage of the amount by which the modified first chrominance value exceeds the local maximum first chrominance value. If the modified first chrominance value is less than the local minimum first chrominance value, the modified first chrominance value of the pixel is increased by a select percentage of the amount by which the modified first chrominance value is less than said local minimum first chrominance value. In accordance with still another aspect of the present invention, a digital image processing apparatus includes means for receiving input digital image data defining a plurality of pixels of an input color digital image, the input digital image data including an input chrominance value for each of the pixels of the input image. The apparatus also includes means for enhancing the input digital image data defining each of the pixels based upon the input digital image data defining neighborhood pixels in a spatial neighborhood established about each of the pixels to obtain enhanced digital image data defining each of the pixels, the enhanced digital image data including an enhanced chrominance value. A means is provided for performing an overshoot control operation on the enhanced digital image data defining each of the pixels, and includes: means for determining a local maximum and a local minimum input chrominance value in a neighborhood about a select pixel; means for comparing the enhanced chrominance value to the local maximum and local minimum chrominance values to determine if the enhanced pixel chrominance value is one of: (i) above the local maximum chrominance value by an overshoot amount; and, (ii) below the local minimum chrominance value by an overshoot amount; means for reducing the enhanced chrominance value to reduce the overshoot amount if the enhanced chrominance value of the select pixel is above the local maximum chrominance value; and, means for increasing the enhanced chrominance value to reduce the overshoot amount if the enhanced chrominance value of the select pixel is below the local minimum chrominance value. In accordance with yet another aspect of the present invention, a method of controlling chrominance channel overshoot includes receiving a plurality of pixels of digital image data, each pixel defined in terms of an original luminance value and first and second original chrominance values. The digital image data are enhanced to convert each pixel of the image into an enhanced pixel defined in terms of an enhanced luminance value and first and second enhanced chrominance values. Local minimum and local maximum first original chrominance values associated with each enhanced pixel in a select neighborhood about each of the enhanced pixels are determined. Local minimum and local maximum second chrominance values associated with each enhanced pixel in a select neighborhood about each of the enhanced pixels are determined. For each enhanced pixel, the first and second enhanced chrominance values associated with the enhanced pixel are compared to the local maximum and local minimum first and second original chrominance values, respectively, to determine: (i) if the first enhanced chrominance value overshoots one of the local maximum and local minimum first original chrominance values by a first overshoot amount; or (ii) if the second enhanced chrominance value overshoots one of the local maximum and local minimum second original chrominance values by a second overshoot amount. For each enhanced pixel, if the first enhanced chrominance value overshoots one of the local maximum and local minimum first original chrominance values, the first enhanced chrominance value is adjusted to reduce the first overshoot amount. Likewise, for each enhanced pixel, if the second enhanced chrominance value overshoots one of the local maximum and local minimum second original chrominance values, the second enhanced chrominance value is adjusted to reduce the second overshoot amount. One advantage of the present invention is the provision of a method and apparatus for chrominance channel overshoot control during digital image processing enhancement operations. Another advantage of the present invention resides in the provision of a method and apparatus for controlling chrominance channel overshoot resulting from edge enhancement processing wherein color fringing is reduced without compromising edge sharpness. A further advantage of the present invention is found in the provision of a method and apparatus for reducing chrominance channel overshoot using original min/max chrominance values from pixels in the neighborhood surrounding a pixel being processed. Still other benefits and advantages of the present invention will become apparent to those of ordinary skill of the art to which the invention pertains upon reading and understanding the present specification. BRIEF DESCRIPTION OF THE DRAWINGS The present invention may take form in various components and arrangements of components, and in various steps and arrangements of steps, preferred embodiments of which are disclosed herein and illustrated in the accompanying drawings which form a part hereof and wherein: FIG. 1 is a diagrammatic illustration of a digital image processing system formed in accordance with the present invention; FIG. 2 is an illustration of a digital image wherein a portion of the digital image is subject to edge enhancement filtering; FIG. 3 graphically illustrates chrominance channel overshoot and control of same in accordance with the present invention; FIG. 4 is a flow chart that illustrates edge enhancement with chrominance channel overshoot control in accordance with the present invention; FIG. 5 is a block diagram illustrating a chrominance channel overshoot apparatus formed in accordance with the present invention; and FIG. 6 is a block diagram illustrating the overshoot control unit of the apparatus shown in FIG. 5 as used for controlling chrominance channel overshoot in accordance with the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings wherein the showings are for purposes of describing preferred embodiments of the invention only and not for purposes of limiting same, a digital image processing system 10 formed in accordance with the present invention is shown in FIG. 1 . An image input unit 12 , such as a scanner, image storage device, and/or computer image generator derives/delivers digital image data in the form of one or more monochromatic separations, wherein the picture elements or pixels of each separation are defined at a depth of d bits per pixel where d is an integer. Accordingly, each pixel of each separation is defined in terms of d bits per pixel (bit depth=d), and each pixel has some gray value between full off and full on. When the digital image data is provided in terms of a single monochromatic separation, the image is monochromatic, for example, so called black-and-white image data. On the other hand, when the digital image data is provided in terms of two or more monochromatic separations, a color image results when the data from the separations is combined, for example, red-green-blue (RGB) separations or cyan-magenta-yellow (CMY) separations. Color digital image data supplied by the image input unit 12 can alternatively be supplied in the form of a luminance-chrominance color space, such as CIELAB or the like, as is well known in the art, and conversion among various color spaces is also contemplated herein. The digital image signals are input from the scanner 12 to an image processing unit 14 wherein digital image processing, such as edge enhancement with chrominance channel overshoot control in accordance with the present invention, is performed. The image processing unit 14 may be provided by any suitable electronic computing apparatus such as a programmed general purpose computer, a dedicated electronic circuit, or any other suitable electronic circuit means. The image processing unit 14 outputs processed digital image data in a suitable format to an image output terminal 16 , such as a storage device, a digital printer, and/or a visual display. Suitable apparatus for digital image input and/or output include the XEROX Document Center 265DC digital imaging system, Pixelcraft 7650 Pro Imager Scanner, XEROX DocuTech Production Printing System scanners, the XEROX 5775 digital color copier, the XEROX 5760 and 5765 Majestik digital color copiers, or any other suitable color digital scanner/copier. Regardless of the depth d at which each pixel is defined, the location of each pixel in each separation bitmap is also defined, typically in terms of a row “n” and a column “m.” FIG. 2 illustrates a color digital image I as derived by the image input terminal 12 . As described above, the image I comprises a plurality of pixels P arranged in m rows and n columns so that each pixel P is uniquely identifiable by a row/column designation mn, e.g., P 22 which represents the pixel P located in the third row and third column. As noted, each pixel P of a color digital image I is defined by several monochromatic gray values or in terms of its luminance and chrominance values depending upon the color space. For convenience and ease of understanding the present invention, the invention will be described in terms of the pixels P being defined in the CIELAB color space. As is generally known in the art, CIELAB is a perceptual color space wherein color is represented in three dimensions according to a lightness value (represented on the L* axis), a redness-greenness value (represented on the a* axis), and a yellowness-blueness value (represented on the b* axis). Thus, the a* and b* chrominance values define first and second chrominance channels for the CIELAB color space. However, those of ordinary skill in the art will certainly recognize that the invention can be carried out in any luminance-chrominance color space and that any other color space, such as RGB, CMYK, or the like is freely convertible into CIELAB or another luminance-chrominance color space. It is not intended that the invention be limited to any particular color space. With continuing reference to FIG. 2, the cross-hatched area F represents a spatial filter as is also well known in the art of digital image processing. In particular, the represented filter F is a finite impulse response (FIR) filter that alters the value of a centrally located subject pixel P based upon the original values of all other neighborhood pixels P, i.e., all other pixels P encompassed by the filter F at a given time. The contribution of each neighborhood pixel to the final value of the subject pixel P varies depending upon the weight assigned to that neighborhood pixel according to the particular filtering operation being performed. As illustrated in FIG. 2, by way of example only, the filter F is an FIR edge enhancement filter of a size that is 5 pixels by 5 pixels (5×5). The central pixel P 22 is the subject pixel, and the remaining pixels P encompassed by the filter are the neighborhood pixels that will be used to alter the value of the subject pixel P 22 for purposes of edge or other enhancement. As is well known, the filter F is applied to each pixel P in the image I for image enhancement operations. The FIR filtering operation, itself, is conventional and does not form a part of the present invention. Thus, any other size/type of FIR or other edge enhancement filter may be used without departing from the overall scope and intent of the present invention. FIG. 3 graphically illustrates chrominance channel overshoot in response to FIR filtering and control of same in accordance with the present invention. The solid line represents chrominance values of the unfiltered image data I for each pixel P, e.g., in the CIELAB color space, the solid line represents either the a* or b* chrominance channel. It can be seen that, in an edge region E of the image I, the chrominance values change from a higher level to a lower level. However, this change in chrominance values is gradual and. the edge region E of the image I is, thus, not well defined or “sharp.” To make the image I more visually appealing, FIR filtering is carried out on the original image I to enhance the edge region E and other edge regions. As is graphically illustrated with a broken line labeled FIR_OUTPUT, after FIR filtering, the transition from a higher chrominance to a lower chrominance in the edge region of the image I is much steeper indicating a much sharper, enhanced edge region E′. However, with reference to the pixel P 22 as an example, its chrominance value has been raised from an original value C 1 to an FIR_OUTPUT value of C 3 . Further, the FIR_OUTPUT chrominance value of the pixel P 22 exceeds a local maximum original chrominance value LOCAL_MAX of pixels P in a neighborhood about the pixel P 22 by an overshoot amount OS. The neighborhood about the pixel P 22 used to identify LOCAL_MAX preferably corresponds to the neighborhood of the filter F, or a subset of same, but may be any other neighborhood in the region of the subject pixel, in this case the pixel P 22 . Accordingly, the chrominance of the pixel P 22 has been altered significantly relative to surrounding pixels, and the appearance of the output image will likewise be altered due to color shift or “fringing” of the pixel P 22 . Similarly, with reference to the pixel P rc , the FIR filtering operation has caused its chrominance value to be reduced from C 4 to an FIR_OUTPUT value C 6 . Also, the FIR_OUTPUT chrominance value is less than a local minimum chrominance value LOCAL_MIN of pixels P in the neighborhood of the pixel P rc by an overshoot amount OS′. Again, the neighborhood used to locate the local minimum chrominance value LOCAL_MIN preferably corresponds to the neighborhood of the FIR filter, itself, or a subset thereof, but may be any other neighborhood in the region of the subject pixel, in this case the pixel P rc . Thus, the chrominance value of the pixel P rc has also been altered in a manner that will sharpen the edge E but cause undesired color shift or fringing relative to the appearance of the original image I. With continuing reference to FIG. 3, it is shown that chrominance channel overshoot control in accordance with the present invention attenuates chrominance channel overshoot OS,OS′. The phantom line OSC represents the pixel chrominance values P for the same edge region at E″ after performance of chrominance channel overshoot control in accordance with the present invention. It is shown that, the overshoot OS associated with of the pixel P 22 is reduced by an amount X=OS *f, wherein, f is a programmable overshoot reduction parameter that can be pre-set or that can vary depending upon the characteristics of the input image I and/or the desired aesthetics of the image output to the image output terminal 16 . Likewise, the overshoot OS′ of the pixel P rc is reduced via overshoot control in accordance with the present invention by an amount X′=OS′*f. However, it is significant to note that the phantom line OSC representing the same edge region at E″ after overshoot control in accordance with the present invention is nearly as steep as the broken line FIR_OUTPUT representing the edge region E′ after FIR edge enhancement. Thus, it can be seen that overshoot control in accordance with the present invention reduces color fringing without significantly compromising edge enhancement or sharpness. In general, chrominance channel overshoot control in accordance with the present invention to obtain a final output chrominance value OSC based upon an input chrominance value FIR_OUTPUT provided after FIR or other edge enhancement operations can be described mathematically by the following: OS = FIR_OUTPUT − LOCAL_MAX OS′ = LOCAL_MIN − FIR_OUTPUT OSC = FIR_OUTPUT − f * OS  if FIR_OUTPUT > LOCAL_MAX; OSC = FIR_OUTPUT + f * OS′  if FIR_OUTPUT < LOCAL_MIN; and, OSC = FIR_OUTPUT  if LOCAL_MIN <= FIR_OUTPUT <= LOCAL_MAX, again, wherein f is programmable chrominance overshoot reduction parameter as noted above. Thus, the amount of overshoot control varies depending upon the value selected for the parameter f. For example, if f=0.25, the overshoot OS,OS′ will be reduced by 25%. Thus, the effects of the FIR enhancement operation are decreased by 25% to prevent undesired color fringing. It is contemplated within the scope of the present invention to change the value for the overshoot reduction parameter f depending upon whether the overshoot to be attenuated is “positive” (FIR_OUTPUT>LOCAL_MAX) as illustrated in FIG. 3 at OS, or “negative” (FIR_OUTPUT<LOCAL_MIN) as illustrated in FIG. 3 at OS′, as either positive or negative overshoot may be deemed more or less objectionable than the other in certain digital image processing operations. Referring now to FIG. 4, chrominance channel overshoot control in accordance with the present invention is described. A step or means SI receives the digital. image data of an original image I. For each pixel P of the original image, a step or means S 2 enhances the image data defining the pixel P using FIR or other edge enhancement filtering. Also for each pixel P of the original image, a step or means S 3 compares the chrominance of the enhanced data defining the pixel P with original (non-enhanced) LOCAL_MIN/LOCAL_MAX chrominance values of other pixels in a neighborhood about the enhanced pixel P. A step or means S 4 determines if the chrominance of the enhanced pixel is greater than LOCAL_MAX and, if so, a step or means S 5 reduces the chrominance of the enhanced pixel P as described above according to the overshoot reduction parameter f. On the other hand, if the chrominance of the enhanced pixel P is less than LOCAL_MAX, a step or means S 6 determines if the chrominance of the enhanced pixel P is less than LOCAL_MIN and, if so, a step or means S 7 increases the chrominance of the enhanced pixel P as described above according to the overshoot reduction parameter f. FIGS. 5 and 6 diagrammatically illustrate an apparatus specifically adapted for performing edge enhancement with chrominance channel overshoot control in accordance with the present invention. As noted above, those of ordinary skill in the art will recognize that the apparatus illustrated in FIGS. 5 and 6 is preferably the image processing unit 14 , programmed or otherwise configured to provide structure and/or operations necessary for the subject invention. Chrominance input values C such as CIELAB a* and/or b* values, are input to a buffer 40 . Preferably, each chrominance channel a*,b* employs an overshoot control system formed in accordance with the present invention as described herein. An FIR edge enhancement filter 42 performs the edge enhancement step S 2 and a neighborhood min/max detector 44 determines the values for LOCAL_MIN and LOCAL_MAX. An overshoot control unit 50 performs chrominance channel overshoot control in accordance with the present invention, in particular, steps S 3 -S 7 , as appropriate, and supplies the resulting chrominance values OSC as output. With particular reference to FIG. 6, the overshoot control unit 50 includes subtractors 52 a , 52 b , sign extractors 54 a , 54 b , a decoder 56 , and a selector 58 that perform the operations S 3 ,S 4 ,S 6 as appropriate to determine if the chrominance value FIR_OUTPUT for an enhanced pixel P is greater than LOCAL_MAX, less than LOCAL_MIN, or between these values. The overshoot reduction parameter f is preferably preprogrammed stored in a register 60 , and a central processing unit CPU causes same to be input to a multiplier 62 , together with the overshoot data OS,OS′ input from the subtractors 52 a , 52 b to perform the above-described multiplication of the overshoot reduction parameter f with the overshoot values OS,OS′. An adder 64 adds the result supplied by the multiplier 62 to the enhanced chrominance value FIR_OUTPUT to complete the overshoot control operations S 5 ,S 7 and obtain the output chrominance value OSC. The invention has been described with reference to preferred embodiments. Modifications and alterations will occur to others upon reading and understanding the preceding specification. It is intended that the invention be construed as including all such modifications and alterations insofar as they fall within the scope of the appended claims or equivalents thereof.

A method and apparatus for digital image processing are provided for controlling chrominance channel overshoot in response to FIR or other enhancement processing. The chrominance values defining the enhanced digital image data for each pixel are compared to corresponding local minimum and maximum chrominance values of the non-enhanced image obtained from the neighborhood of the subject pixel. If an enhanced chrominance value for a subject pixel falls outside the corresponding local minimum/local maximum chrominance range by an overshoot amount, the enhanced chrominance value is adjusted to reduce the overshoot amount. The overshoot amount is adjusted according to a pre-programmed overshoot reduction parameter.

ORIGIN OF THE INVENTION The invention described herein was made by an employee of the United States Government, and may be manufactured and used by the government for government purposes without the payment of any royalties therein and therefor. FIELD OF THE INVENTION The innovation describes various methods of fabricating packages used for protection of electronics and sensors in high temperature environments. Apparatuses made by the various methods of fabricating sensor sub-assemblies and their final packaging are also disclosed. BACKGROUND OF THE INVENTION My copending U.S. patent application Ser. No. 10/124,689; filed Apr. 12, 2002, entitled MULTI-FUNCTIONAL MICRO ELECTROMECHANICAL DEVICES AND METHOD OF BULK MANUFACTURING SAME discloses and claims a method of bulk manufacturing SiC sensors, including pressure sensors and accelerometers. The disclosure of my copending application is incorporated herein by reference. I am a named inventor of U.S. Pat. No. 5,637,905 to Carr et al. and it discloses a high temperature pressure and displacement microsensor made from a Si substrate. A first coil structure is positioned within a recess in the Si substrate. A pressure diaphragm is glass bonded about its periphery to the rim of the recess in the semiconductor substrate. A second coil structure is positioned on the underside of the pressure diaphragm and is electrically isolated from the first coil structure. The coils are inductively coupled together and provide an output indicative of changes in the coupling between the coils. My U.S. Pat. No. 6,248,646 discloses a process for making an array of SiC wafers on standard larger industry sized wafers. This patent discusses the operating conditions for SiC and SiC-On-Insulator technology and cites the need for sensors made from SiC. U.S. Pat. No. 5,973,590 to Kurtz et al. discloses a hermetically sealed semiconductor sensor bonded to first and second glass wafers. U.S. Pat. No. 6,319,757 BI to Parsons et al. discloses a silicon-carbide wafer bonded to an underlying ceramic substrate. The '757 patent states at col. 6, lns. 7-13 that the silicon carbide semiconductor substrate is a SiC die and the underlying substrate is polycrystalline aluminum nitride. Parsons et al. further states that the expansion coefficients of aluminum nitride and silicon carbide are nearly identical in the aforementioned structure and that of the borosilicate (BSG) glass encapsulant is close enough to both silicon carbide and aluminum nitride so as to avoid separation or cracking over a wide temperature range. Parsons et al. also teaches a flip chip application in FIG. 3 thereof encapsulated in glass. U.S. Pat. No. 5,891,751 to Kurtz et. al describes curing a glass frit bonding the cover to the transducer. Upon curing, the glass frit becomes the peripheral glass layer 106 . During the curing process, gasses are created which escape through an aperture designed for the purpose of the escaping gasses. According to the '751 patent, the aperture prevents the glass frit from bubbling and out gassing during the curing process which would prevent a hermetic seal along the periphery of the structure. The aperture accordingly must be within the inner periphery of the glass. See, the '751 patent at col. 7, lns. 5-17. In FIG. 1 herein reference numeral 100 is used to indicate the prior art drawing FIG. 7 of the '751 patent. Referring to FIG. 1 herein, Kurtz et al. identify transducer 101 which includes silicon (Si) diaphragm 103 and dielectric 102 (silicon dioxide). Glass 106 bonds silicon (Si) cover member 105 to the transducer (sensor). Aperture 108 permits out gassing during curing so as to not ruin the glass bond 106 and the seal it makes. Piezoresistors 109 reside on the dielectric 102 . Glass bottom cover 104 includes aperture 107 . In FIG. 2 herein, reference numeral 200 identifies the prior art drawing FIG. 8 of the '751 patent illustrating electrostatic bonding of glass sheet 201 to the top cover 105 to seal aperture 108 under vacuum conditions. Contact pads 202 are exposed in the prior art. FIG. 3 herein is a duplicate of FIG. 4 of U.S. Pat. No. 6,058,782 to Kurtz et al. Reference numeral 300 signifies one of the hermetically sealed ultra high temperature silicon carbide pressure transducers of the '782 patent which has been cut or diced. See, col. 3, lns. 52-54. Referring to FIG. 3 , silicon carbide first substrate 302 having unnumbered piezoresistors thereon bonded to silicon carbide second substrate 303 by electrostatic bonding or by glass frit bonding. See, col. 6, lns. 9-23 of the '782 patent. If bonded by a glass frit the same is not illustrated in the '782 patent as no space is shown between substrates 302 and 303 in FIG. 3 . Further no provision or illustration is made for the escape aperture which must reside in second substrate 303 which might be referred to herein as the cover. Sensor 302 and cover 303 , bonded together are illustrated as being in engagement with header 304 which carries a glass insulator (unnumbered) bonded to the top cover. Referring again to FIG. 3 , leads 301 are illustrated in engagement with a platinum glass frit 305 electrically communicating with contact pads 306 . Referring to FIG. 3 , the second substrate 303 is mounted atop glass which is unnumbered in FIG. 3 . Since the glass expands at a rate of thermal expansion which is different than the substrate 303 , stress is applied to the second substrate which may cause the separation of the pins 301 from the contact pads 306 of the first substrate. Stress may also be applied to the piezoresistors on the first substrate inducing measurement error. The use of electrostatic bonding method makes very weak bond strength between the SiC sensors and the SiC cover. This may lead to debonding during thermal cycling thereby rendering the device useless. Application of glass frits as the adhesion material between the SiC cover and the SiC sensor makes necessary the creation of an aperture as an escape path for out gassing during glass bonding. Since the aperture will have to be sealed later in order to maintain the desired hermetic reference cavity, it increases the risk of the sealant sipping into the reference cavity. There is growing demand for improved efficient management of energy consumption in jet engines and automobiles. Global reduction of undesirable emissions of hydrocarbons and other combustion by-products such as oxides of nitrogen and carbon monoxide are being sought assiduously. Semiconductor based sensors and electronics targeted for insertion in high temperature, extreme vibration, and corrosive media must satisfy a set of minimum reliability criteria before becoming acceptable for operational use. In addition, it is crucial to validate the Computational Fluid Dynamics codes generated for flow fields and turbulent conditions inside engines. Validation of these codes is necessary to render them trustworthy. Devices capable of functioning in these harsh environments need the appropriate package to sustain stable and reliable operation during the life of the device. Package reliability problems have largely contributed to prevent the application of these devices. Typically these devices operate in environments of 300° C. and above. This is very challenging since conventional semiconductor electronic and sensing devices are limited to operating in temperatures less than 300° C. due to the limitations imposed by material properties and packaging. Silicon carbide-based electronics and sensors have been demonstrated to operate in temperatures up to 600° C. thereby offering promise of direct insertion into the high temperature environment. However, the lack of the device (sensor) packaging methodologies appropriate for this harsh environment has affected the operational reliability and survivability of these devices (sensors). Reliability problems at high temperature due to poor packaging has discouraged global application and large-scale commercialization of these devices. As such, the much anticipated introduction of SiC devices into high temperature environments has been delayed. SUMMARY OF THE INVENTION The basic components comprise a bottom substrate member of a dielectric material with thermomechanical properties similar or closely similar to that of silicon carbide, silicon or aluminum nitride. The bottom cover substrate member serves as a receiving platform for the silicon carbide sensors. The sensors may also be made of aluminum nitride or silicon. It also serves as the first level of protection of the sensor from harmful particulates in the high temperature environments in which the sensor is employed. Typically, the bottom substrate has a hole or aperture therein which allows pressure and/or temperature to be transmitted to the sensor. The top cover substrate made from the same material as the bottom substrate provide sandwiched protection for the sensors. Because they are made of the same material with thermomechanical properties similar to that of the sensors, the problem of mismatch in the coefficient of thermal expansion associated with the prior art is significantly reduced. The bottom substrate includes housings in an array formed by walls. Between the walls of the housings are gaps or openings. The housings are sized to accommodate the insertion of similarly shaped, but smaller, sensors. The top substrate includes top covers in an array. The top covers are similarly shaped to the sensors which they cover but are smaller. In this way, when the bottom and top substrates sandwich the sensors together the peripheries of the top cover, the sensor and the housing are exposed so that glass may seal and bind them together. The top substrate includes larger gaps than the bottom substrate to enable glassing before cutting or dicing the sandwiched array into individual sensor sub-assemblies. The manufacture of the sensors are taught in my copending U.S. patent application Ser. No. 10/124,689, filed Apr. 12, 2002, entitled MULTI-FUNCTIONAL MICRO ELECTROMECHANICAL DEVICES AND METHOD OF BULK MANUFACTURING SAME. The bottom and top substrates of the instant invention can be manufactured using the teachings of my copending application. The drawing figures used herein do not illustrate the piezoresistors on the sensors but it will be understood by those skilled in the art that where the term sensor is used it shall include but not be limited to the sensors as described in my application referenced herein. The packaging methodologies and apparatuses disclosed herein are not limited solely to the sensors of my invention as set forth in my copending patent application but may include sensors of a different design as well as prior art sensors. The top cover substrate has several important features. First, it has four through holes spread equidistantly. These holes accept wires or pins that are used to make intimate contact with the contact pads on the sensor. A shallow circular or rectangular recess is located on one face of the top cover substrate and this is known as an over-pressure protection or reference cavity. When the top cover substrate is placed on the bottom cover substrate, the recessed cavity in the top cover substrate faces down so that the moving part of the sensor (i.e. a diaphragm in the case of a pressure sensor or an inertial mass in the case of an accelerometer) lies within its peripheral boundary. Several types of high temperature glasses exist that are used for providing hermetic sealing for the sensor after encasement between the top and bottom substrates. The pins that are inserted into through holes of the top cover substrate can be made of platinum, gold or nickel. Various embodiments of a stainless steel screw housing and Kovar header are applied either separately or together in the fabrication and assembly process for the final packaging. Kovar is a trademark of Westinghouse Electric Corporation and is an iron-nickel alloy used in making metal to glass seals. Methods of bulk manufacturing high temperature sensor sub-assembly packages are disclosed. Sensors are sandwiched between a top cover and a bottom cover so as to enable the peripheries of the top covers, sensors and bottom covers to be sealed and bonded securely together are disclosed. Sensors are placed in the bottom covers leaving the periphery of the bottom cover exposed. Likewise, top covers are placed on the sensors leaving the periphery of the sensor exposed. Individual sensor sub-assemblies are inserted into final packaging elements which are also disclosed. Methods of directly attaching wires or pins to contact pads on the sensors are disclosed. Sensors, such as pressure sensors and accelerometers, in combination with headers made out of silicon carbide and aluminum nitride are disclosed. Reference cavities are formed in some embodiments where top covers are not employed. The basic method of bulk packaging sensors comprises the steps of placing a bottom substrate having an array of sensor housings in a holding device to receive sensors, inserting a sensor having contact pads in each housing of said bottom substrate, and, placing a top substrate having an array of covers onto each respective sensor. The peripheries of the top covers, sensors and bottom covers are then secured and hermetically sealed with glass and then cut or diced into individual sensor sub-assemblies. The sub-assemblies can be further packaged into final packaging. The housings (cells) are substantially rectangularly shaped and include a rectangular perimeter wall having an inside portion and an outside portion. Each sensor includes a substantially rectangular perimeter shorter in length than the rectangular perimeter wall of each housing. Each top cover has a substantially rectangular perimeter shorter than the perimeter of each sensor. Each sensor has the same, but proportionally smaller, rectangular shape as the housing (cell) walls and the top cover has the same, but proportionally smaller, rectangular shape as the sensor. In this way a portion of the bottom housing between the sensor and the walls of the housing are left exposed for glassing. Similarly a portion of the top of the sensor is left exposed for glassing. This creates a step-like appearance in cross-section which enables glassing over the perimeter or peripheries and avoiding out gassing concerns which plague the prior art of Kurtz et al. discussed above. Each sensor includes a plurality of contact pads and each top cover includes a plurality of bores or through holes. A plurality of pins (nickel, gold or platinum) extend through the bores of the top covers and engage the plurality of contact pads. Conductive paste resides in the bores in the top covers for securing the pins to the top covers and the contact pads. Glass secures the pins to the top of the top covers to add further mechanical rigidity to the pins. A method of direct contact attachment of a pin to a contact pad on a sensor is disclosed and comprises dipping one end of the pin into a high temperature conductive paste that cures at a temperature less than the softening point of the glass used for sealing, inserting the pin coated with conductive paste until it engages the contact pad, firing the assembly to a temperature to cure the conductive paste, cooling the assembly, applying glass to the pin and the top cover to secure the pin to the cover, and, firing the assembly to the glass curing temperature. Optionally, the step of filling the through hole partially with nickel may be performed before dipping the pin in the conductive paste and inserting the pin in the through hole such that the pin engages the nickel. A packaged sensor sub-assembly comprising just a sensor and a top cover glassed to a Kovar header which has been fused to a stainless steel housing is disclosed. Alternatively a packaged sensor sub-assembly comprising a bottom member, a sensor and a top cover may be glassed to a Kovar header which has been fused to a stainless steel housing. A method for packaging a sensor sub-assembly, comprising the steps of: brazing a Kovar header to a stainless steel housing, inserting the sensor sub-assembly into the Kovar header, and, glassing the sensor sub-assembly to the Kovar header is disclosed. The steps of inserting the sensor sub-assembly into the Kovar header and glassing the sensor sub-assembly to the Kovar header are performed before the step of brazing the Kovar header to the stainless steel housing. Alternatively, a sensor subassembly may be inserted into a stainless steel housing having threads on the interior of the housing. The threads, sensor sub-assembly and the pins are then glass sealed within threaded housing. Preferably, the glass seal length should be at least 10 times the thickness of the sensor sub-assembly. And, the interior threads should include at least 5 ribs. The stainless steel housing will also preferably include threads on the exterior thereof so as to enable mounting to equipment or processes to be monitored. A sensor subassembly housing comprising a stainless steel housing having an interior and an exterior and which includes threads thereon is disclosed. A ceramic tube resides in the interior of the stainless steel housing. Brazing resides intermediate the interior threads of the stainless steel housing and ceramic tube and secures the ceramic tube and the stainless steel housing together when heated. The ceramic tube has first and second ends and the first end is smoothened so as to be coplanar with the wires or pins residing in bores of the ceramic. A blow-out stopper of at least 100 mils is used to ensure that the ceramic is not pushed out of the housing when the housing is coupled with a sensor sub-assembly. A particulate shield is used on the housing which protects the sensor sub-assembly when installed in the housing. A thermocouple passes through the ceramic tube in one of the bores. A sensor sub-assembly is secured to the stainless steel housing and the ceramic tube by glass creating a reference cavity. Metal bumps may be used on the contact pads of the sensor to facilitate connection to the wires (pins). Alternatively, through holes in the top cover may be filled with nickel so as to form a transconnect and the transconnect, in turn, engages the metal bumps. Glass secures the top cover, sensor, transconnect and bottom housing together forming a reference cavity bounded by the top cover, sensor and glass. The top cover includes top and bottom surfaces and said transconnect extends radially from the through holes onto the top and bottom surfaces of the top cover. A sensor sub-assembly housing comprising a stainless steel tube, a ceramic tube having through holes, a reference cavity, and an opening therein are disclosed. The ceramic tube is partially brazed to the stainless steel tube. The ceramic tube extends outside the stainless steel tube a sufficient length to thermally decouple the stainless steel tube from the sensor. Through holes of the ceramic tube are aligned with the contact pads of the sensor. Conductive pins residing in the through holes and engage the contact pads of the sensors. Conductive paste secures the pins to the through holes. Glass secures the sensor, bottom housing and ceramic housing together. A method of packaging a sensor comprising the steps of: dropping a sensor sub-assembly into a stainless steel housing, inserting sealing glass into the interior of the housing, and, curing the sealing glass is disclosed. The stainless steel housing includes exterior threads for affixing the sensor to a process to be measured. A method of packaging a sensor sub-assembly comprising the steps of: inserting a ceramic tube inside a stainless steel housing, the ceramic tube having through holes, and the stainless steel housing includes an interior having threads thereon, inserting brazing material in the gap intermediate the stainless steel housing and ceramic tube such that the brazing material is conformal to the interior threads, heating the brazing material and securing the ceramic tube to said stainless steel housing, inserting a sensor sub-assembly having contact pads into the stainless steel housing in alignment with the through holes of the ceramic tube and in proximity to the ceramic tube, and, inserting and heating glass to secure the sensor sub-assembly to the ceramic tube and the stainless steel housing forming a reference cavity is disclosed. Pins coated with a conductive or non-conductive paste are inserted into the through holes of the ceramic tube and into engagement with the contact pads. Heating the paste secures the pins to the ceramic tube and contact pads. A metal bump may be placed on each of the contact pads prior to the step of inserting the sensor sub-assembly having contact pads into the stainless steel housing in alignment with the through holes of the ceramic tube and in proximity to the ceramic tube. An additional step in the process may include inserting a blow-out stopper in the interior of the stainless steel tube prior to heating the brazing material and securing the ceramic tube to the stainless steel housing. Another step to the process may include attaching a particulate shield to the stainless steel housing to protect the sensor sub-assembly. Another method of packaging a sensor sub-assembly in a stainless steel housing having an interior and an exterior is disclosed. This method discloses the steps of: coating pins with paste, inserting the coated pins into a ceramic tube having through holes, placing the coated pins inside the through holes in the ceramic tube and heating the paste to secure the pins to the ceramic tube, smoothening one end of the ceramic tube and the pins located therein such that the end of the pins are coplanar with the ceramic tube, attaching pins to bumps on contact pads of a sensor, heating the ceramic tube and the sensor and bumps on the contact pads, prewetting the interior of a stainless steel housing with a glass paste, inserting the ceramic tube and sensor in the interior of the prewet stainless steel housing, inserting additional glass to secure the sensor to the ceramic tube and the stainless steel housing to form a reference cavity, firing the ceramic tube, the sensor and the stainless steel housing to cure the glass. The step of firing the ceramic tube, the sensor and the stainless steel housing to cure the glass is performed at 800 degrees centigrade for 30 minutes in a nitrogen ambient environment. The step of heating the ceramic tube and the sensor and bumps on the contact pads is performed at 650 degrees centigrade. A method of packaging a sensor sub-assembly in an aluminum nitride header partially secured within a stainless steel housing having an interior, an exterior and a reference cavity formed therein with the sensor sub-assembly including contact pads is disclosed. The method comprises the steps of: coating the aluminum nitride header with a metallic material; inserting the aluminum nitride header having four through holes therein into the stainless steel housing, attaching the metallic material (i.e., nickel) to the stainless steel housing, coating through hole openings with conductive paste, inserting conductive pins in the through holes coating the holes with conductive paste, heating the header, stainless steel housing, pins and conductive paste so as to cure and harden the conductive paste, reapplying the conductive paste on the cured and hardened conductive paste which is proximate the reference cavity, inserting the sensor sub-assembly in the reference cavity such that the sensor contact pads are aligned with the through holes of the aluminum nitride header, heating and bonding the sensor sub-assembly to the reference cavity such that electrical conductivity may be established between the contact pads and pins, and, sealing between the aluminum nitride header and sensor locking air (or vacuum if desired) between the reference cavity and the sensor. The step of attaching the metallic material to the stainless steel housing may be performed by laser welding. The step of attaching the metallic material to the stainless steel housing may be performed by brazing. Accordingly, it is an object of the invention to effect the various methods of fabricating packages used for protection of electronics and sensors in high temperature environments. It is a further object of the invention to produce apparatuses made by the various methods of fabricating sensor sub-assemblies and their final packaging. It is an object of the invention to produce and utilize semiconductors having similar coefficients of thermal expansion (CTE) such as aluminum nitride, silicon and silicon carbide. Therefore, because the sensor is sandwiched by aluminum nitride or silicon carbide, very little CTE mismatch exists. Therefore, minimal thermomechanically-induced stress is transmitted to the device. As a result, fatigue is greatly minimized and the lifetime of device operation is extended. It is an object of the invention to employ glass coupled to the sensor sub-assembly. Since the glass does not adhere well to the stainless steel, it is partially de-coupled ensuring that less stress is transmitted to the sensor and also that the CTE of the glass is close to the CTE of the sub-assembly unit. The sensor and the cover members are partially enveloped in high temperature glass to provide hermetic sealing of the reference cavity. The only section not covered in glass is the sensor diaphragm. It is an object of the invention to employ pins attached to the top cover substrate by first wetting the pins in conductive paste before inserting them into the through holes. The conductive paste in turn wets the previously fired gold paste that is used to hold the sensor and the top cover member together. At this point, the pins are in direct contact with the sensor. It is an object of the invention that the aluminum nitride is fabricated by MEMS-EDM (electro-discharge method) and/or deep reactive ion etching. It is an object of the invention to use inner threading of a stainless steel housing as a mechanical anchor making it possible to circumvent the problem of glass adhesion to stainless steel. In this design, the glass will anchor itself to the stainless steel and provide a tortuous path for a leak. It is an object of the invention to eliminate the Kovar header and directly braze the ceramic to the stainless steel as shown. It is an object of the present invention to use a blowout stopper as a safety mechanism. It is an object of the present invention to bulk manufacture very high temperature sensor sub-assemblies, cut or dice them into individual sensors, and then final package the sensors for use in measuring process variables. It is an object of the present invention to bulk manufacture very high temperature sensor sub-assemblies by sealing and securing the peripheries of the individual components of the sub-assemblies with glass. It is object of the present invention to final package a sensor sub-assembly in a stainless steel housing using a Kovar header brazed to the stainless steel housing. The Kovar header may be first brazed to the housing followed by insertion of the sensor sub-assembly with the sensor sub-assembly then being glassed to the Kovar header. Alternatively, it is a further object to first secure the sensor sub-assembly to the Kovar header and then insert the header and sensor sub-assembly into the stainless steel housing. It is an object of the invention to directly attach the wires (pins) to the contact pads of the sensors. Conductive paste is applied along the length and ends of the wires or, alternatively, it is applied at the entrance to the through holes of the top cover such that when the wires are inserted in the through holes they pick up some of the conductive paste and distribute it along the wire securing the wire to the through holes and the contact pads upon curing of the paste. It is an object of the invention to provide glass attachment of the wires (pins) to the top cover to provide reinforcement and rigidity of the attachment of the wires to the top substrate. It is an object of the invention to provide a stainless steel housing having interior threads. Typically this housing is a screw housing but it can really take on any shape or configuration imagined by the artisan. It is a further object to attach glass to the interior screw threads or ribs and the sensor subassembly. Preferably, the glass engages numerous courses of screw threads or ribs over a long length which provides a prohibitively tortuous path for any leakage gas from the process to pass. It is a further object of the present invention to employ a ceramic tube for insertion into the stainless housing. The tube may be affixed to the interior of the housing using brazing and/or glass affixed to interior threads on the housing. It is a further object still that the tube includes passageways or through holes in which the wires reside and align with the contact pads. Additionally, a passageway or through hole in the tube accommodates a thermocouple lead. It is a further object of the present invention to provide a metal bump of approximately 5 microns out of plane on the contact pads of the sensors to facilitate engagement of the wires (pins) to the contact pads. In another embodiment of the invention, a transconnect of nickel fills the through holes of the top cover and engage either the contact pads of the sensor directly or the metal bumps on the contact pads. The metal bumps can be made of gold, silver, platinum, nickel, titanium, tantalum silicide, or platinum or any combination thereof. It is a further object of the present invention to provide a housing for a sensor-sub assembly wherein a stainless steel tube is employed and inserted within the tube is a generally cylindrically shaped aluminum nitride header having a coating of braze material thereon. The aluminum nitride header is affixed to the stainless steel tube upon heating of the housing. The aluminum nitride extends considerably outside the stainless steel tube so as to effectively thermally decouple the aluminum nitride from the stainless steel housing providing thermal stability to the header and to a sensor mounted within the header. A reference cavity is included in the header and the header acts as the top cover. In this embodiment no top cover is used as its function is supplied by the aluminum nitride header. The reference cavity is sealed when the sensor is glassed to the header. A better understanding of the objects of the invention will bc had when reference is made to the Brief Description Of The Drawings and the claims which follow hereinbelow. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of the prior art illustrating glass frit securing the top cover to the sensor. FIG. 2 is a perspective view of the prior art illustrating electrostatic bonding of the top cover to the sensor. FIG. 3 is a cross-sectional view of the prior art illustrating the first substrate bonded to the second substrate by either glass frit or electrostatic bonding. FIG. 4 is a plan view of the instant invention illustrating a portion of the bottom cover or substrate, a sensor in the housing of one cell of the bottom cover substrate, and a sensor in another cell of the bottom cover along with the top cover residing above the sensor. The top cover has been shown diagrammatically and without the rest of the top cover substrate. FIG. 5 is a plan view a portion of the top cover with a portion thereof undercut so as to permit a hermetic glass seal of the top cover, sensor and bottom substrate. FIG. 6 is a diagrammatic cross-sectional view of a single cell of the array illustrating the housing of the bottom substrate or cover, a sensor together with contact pads, and a top cover with a reference cavity and bores for receiving pins. FIG. 6A is a diagrammatic cross-sectional view of a single cell of the array similar to FIG. 6 with the components sealed and secured together with glass. FIG. 6B is a diagrammatic cross-sectional view of a single cell of the array similar to FIG. 6 with just the housing and the sensor secured thereto including the contact pads. FIG. 7 is a cross-sectional view of an alternative embodiment similar to FIG. 6 without the bottom cover substrate but includes the contact pads. FIG. 7A is a cross-sectional view similar to FIG. 7 with the components sealed and secured together with glass. FIG. 8 is a cross-sectional view illustrating pins attached to contact pads by conductive paste. The pins are first attached to the pads with conductive paste used to secure them to the holes and to the pad. Next, glass paste is used to further secure the pins to the top cover to provide mechanical rigidity of the pins. FIG. 8A is an enlargement of a portion of FIG. 8 . FIG. 8B is a cross-sectional view similar to FIG. 8 with the pins attached to nickel which partially fills through holes. Conductive paste secures the contact pins to the nickel. Next, glass paste is used to further secure the pins to the top cover to provide mechanical rigidity of the pins. FIG. 8C is an enlargement of a portion of FIG. 8 B. FIG. 8D is an enlargement similar to FIG. 8A illustrating the pin in contact with the contact pad 406 . FIG. 9 is a cross-sectional view of a stainless steel screw housing brazed to a Kovar header at high temperature. FIG. 10 is a cross-sectional view of FIG. 9 together with a sensor sub-assembly inserted into the Kovar header which was previously brazed to the stainless steel housing and affixed together prior to insertion within the stainless steel housing. FIG. 11 is a cross-sectional view of a stainless steel screw housing with a brazed Kovar header and a sensor sub-assembly being inserted therein. FIG. 12 is a cross-sectional view of a double-threaded stainless steel screw housing. FIG. 13 is a cross-sectional view of a double-threaded stainless steel screw housing together with a sensor sub-assembly inserted therein together with a glass seal. FIG. 14 is a cross-sectional view of a double-threaded stainless steel screw housing with a ceramic tube placed therein. Braze material is placed between the ceramic tube and interior threads of the stainless steel screw housing. FIG. 14A is a cross-sectional view similar to that of FIG. 14 with a sensor sub-assembly having been inserted prior to insertion of the ceramic tube and blow-out stopper. The blow-out stopper is machined in the stainless steel housing. FIG. 15 is a cross-sectional view of a sensor illustrating bump or stud metal affixed to contact pads on the sensor. FIG. 16 is a cross-sectional view of a ceramic tube having pins secured therein. The pins engage the sensor and a bump or stud metal affixed to contact pads on the sensor. FIG. 17 is a cross-sectional view similar to that of FIG. 14 together with a sensor sub-assembly inserted therein. FIG. 18 is an alternative embodiment of the sensor in combination with a top cover having a transconnect. FIG. 19 is similar to FIG. 18 and illustrates the securement of the top cover, sensor and bottom substrate with glass. FIG. 20 is a cross-sectional view of an aluminum nitride ceramic tube having bores therethrough inserted into a long stainless steel tube to thermalmechanically decouple the device from the tube. FIG. 21 is a cross-sectional view along the lines 21 — 21 of FIG. 20 . FIG. 22 is a cross-sectional view along the lines 22 — 22 of FIG. 20 . A better understanding of the drawings and invention will be had when reference is made to the Description of the Invention and claims which follow hereinbelow. DESCRIPTION OF THE INVENTION FIG. 4 is a plan view 400 of the instant invention illustrating a section of the array of the bottom cover or substrate 402 , a sensor 405 in the housing of one cell 407 of the bottom cover substrate 400 , and a sensor 405 in another cell 407 of the bottom cover substrate along with the top cover 409 residing above the sensor 405 . Top cover 409 is illustrated diagrammatically and is shown not connected to the array of which it is a part. In one embodiment, each sensor or electronics chip 405 is dropped into the corresponding cells 407 arranged in an array 400 as shown in FIG. 4 . The cell-array 400 is made from material that will survive high temperatures up to 700° C. such as aluminum nitride or silicon carbide, preferably in amorphous form for reduced cost without loss of performance. It will also have thermomechanical properties close to that of the material in which the chip 405 is made. Typically, the sensor chip will be made from silicon carbide or aluminum nitride as taught in my copending patent application referred to above and incorporated herein by reference. The port hole 403 in each cell 407 allows pressure to be applied to the diaphragm 414 on the sensor 405 if the sensor requires such. The depth of the recess of the cell 407 and its width will be such that it accommodates the chip as shown in the example of FIGS. 4 and 6 . After the sensors 405 are inserted into the recess of cell 407 as shown in FIGS. 4 and 6 , an arrayed prefabricated top cover substrate 500 as shown in FIG. 5 is aligned and placed over the bottom cover substrate 400 . One of the top covers 409 is shown in FIG. 4 without the remainder of the structure of the array 500 of the top cover substrate. Top cover 409 illustrates a reference cavity 415 which may be a pressurized cavity or a vacuum reference cavity. If the substrates are glassed under vacuum conditions then the reference cavity will be at or near zero psia. The four circular through-holes 412 in the top cover substrate 409 are designed to accept wires that will make intimate mechanical and electrical contact with the corresponding contact pads 406 of the sensors resident in the recessed cell array of FIG. 4 . Thus each sensor 405 in a cell 407 has four contact pads 406 in intimate contact with the pins. Pins 801 are shown in FIG. 8 and may be gold, platinum, nickel or alloys of refractory metals. FIG. 5 is a plan view 500 of the top cover substrate. Referring to FIG. 4 , the array 400 is formed by joining sections 401 and gaps 402 between walls 404 which define recesses or cells 407 . Recesses or cells 407 include a bottom portion 418 having an aperture 403 therein. Referring again to FIG. 5 , joining portions or tabs 501 support top covers 409 . Tabs 501 include undercut portions 503 which enable complete glassing of the top cover substrate to the sensors and the bottom cover substrate. Undercut portions 503 may take on different geometry as desired to effect complete hermetic sealing. Tabs 501 may take other forms including bridge formations enabling glassing patterns so as to enable complete encasing and hermetic sealing of the top cover substrate to the sensors and the bottom cover substrate. Gaps 502 , wider than gaps 402 , are illustrated in FIG. 5 . The wider gaps facilitate application of the glass prior to heating and dicing the sandwiched substrate into individual sensor sub-assemblies. Referring again to FIG. 4 , reference numeral 408 illustrates the portion of the bottom substrate which is not covered by the sensor 405 and reference numeral 410 represents the portion of the sensor 405 which is not covered by the top cover 409 . Reference numeral 415 indicates the reference cavity in top cover 409 . The direct chip attach (DCA) process disclosed herein eliminates the need for wirebond and the associated failure mechanisms at high temperature. In the prior art, gold wirebonding is used to make electrical connection from the sensor to pins. However, gold diffusivity into the ohmic contacts on the pads increases rapidly with temperature, which contributes to electrical and mechanical degradation at the bond interface. The instant DCA approach allows the flexibility of using platinum or other types of high temperature wires or pins 801 that do not readily diffuse at high temperature. It is desired that this top cover should also be of the same material as the bottom cover in order to maintain symmetry of the coefficient of thermal expansion (CTE). In the prior art, little consideration is given to package related thermally-induced stress in terms of its impact on the mechanical and ultimately electrical functionality and long-term reliability of the sensor. The existence of thermally-induced stress during thermal cycling is known to induce fatigue at several critical areas of the system such as fatigue at the wirebond/pad interface. For instance, in FIG. 3 , the thermal expansion mismatch between the glass and the second substrate and the glass and the metal header creates unwanted stress and/or failure of the sensor. Referring to FIG. 6 , the centrally located recessed area 415 of the top cover 409 is a shallow cavity that will lie directly above the active moving part 603 of the sensor 405 below. Sensor 405 deflects above the diaphragm 414 and this is the active portion 603 of the sensor. Piezoresistors are not shown on or in sensor 405 . The section outside this recessed area 415 will be in intimate contact with the corresponding sensor sections outside the active area as illustrated in FIGS. 6 and 7 . Recessed area 415 allows the moving part of the sensor 405 adequate room to deflect and also protect the moving part from over-deflecting. The cavity volume (i.e. the recessed area 415 ) also acts to provide a reference pressure when hermetically sealed and used as an absolute pressure sensor or control of damping in an accelerometer as desired and as dictated and controlled at the time of glassing. Referring to FIG. 5 , the grid openings 502 on the sides of this top cover substrate 500 will be wider than the grid openings 402 ( FIG. 4 ) of bottom cover substrate 400 so that peripheral sections 410 of the sensor 405 in each cell 407 are visible. That means the perimeter of the top cover 409 of the top substrate 500 is the smallest of the three components (top cover, sensor and cell 407 ). The top cover substrate 500 is placed over the bottom cover substrate 400 having sensors in each cell and aligned such that through holes 412 are placed over contact pads 406 . High temperature glass paste is applied into the grid openings 502 , 402 from the perimeter of each component. The glass paste will come in contact with the peripheral edges of the sensors 405 , the bottom 400 and top cover 500 substrates. The glass is then cured at high temperatures greater than the anticipated operating temperature of the device. As a result of the glass coming in contact with the periphery of the sensors 405 , the bottom cover 400 and the top cover 500 substrates, a hermetic sealing of the volume cavity 415 in the over-pressure protection section is achieved. A cross section of the three components (sensor 405 , top cover 500 and bottom cover 400 substrates) are shown below in FIG. 6 to better illustrate the inter-relationship during the glass sealing process. FIG. 6 is a diagrammatic cross-sectional view of a single cell 600 of the array illustrating the housing or cell 407 of the bottom substrate or cover, a sensor 405 having contact pads 406 , and a top cover 409 with a reference cavity 415 and bores 412 for receiving pins 801 . FIG. 6 illustrates components of a single cell 600 of the array prior to bringing all the components in intimate contact with each other. Top cover 409 includes an area 602 proximate to through hole 412 about which conductive paste can be spread as described below. The conductive paste is dragged inside through hole 412 when pins 801 are inserted therein for engagement with contact pads 406 . Referring to FIGS. 6A , 7 A, 10 and 11 , it can be seen that the glassing section will come in contact with the three components enveloping them so as to provide the necessary hermetic sealing to create a reference cavity or, in the case of an accelerometer, damping cavity 415 . It will be understood that the cells 407 may be any shape and that the sensors 405 must be similarly shaped but proportionally smaller than the cell 407 so that they will fit into the cells. Similarly, the top covers 409 must be similarly shaped but smaller than the sensors. The cells 407 , sensors 405 and top covers 409 of the preferred embodiment are generally rectangularly shaped and are stacked upon each other leaving room about the area 408 between the sensor 405 and the wall 404 for glass to fill. Similarly, the lip 410 of the sensor 405 is left uncovered by the top 409 enabling space for the glass to hermetically seal and secure the top cover 409 to the sensor 405 . FIG. 6A is a diagrammatic cross-sectional view 600 A of a single cell 407 of the array similar to FIG. 6 with the components sealed and secured together with glass 601 . FIG. 6B is a diagrammatic cross-sectional view 600 B of a single cell of the array similar to FIG. 6 with just the housing 407 and the sensor 405 secured thereto. FIG. 7 is a cross-sectional view of an alternative embodiment 700 similar to FIG. 6 without the bottom cover substrate. Referring to FIG. 7 , the bottom cover 418 has been eliminated and the top cover substrate 500 can be brought in direct contact with the sensors 405 . The sensors 405 have been previously batch fabricated as taught in my copending patent application referred to above or as produced by another process. Referring to FIGS. 8 , 8 A and 8 B, glass 803 seals and secures the top cover 409 and the boundary or walls 404 of each cell 407 of the sensor array so that hermetic sealing 803 is provided. FIG. 7A is a cross-sectional view 700 A similar to FIG. 7 with the components sealed and secured together with glass 601 . In either embodiment, FIG. 6A or FIG. 7A , the now fully sandwiched and sealed sub-assemblies are then separated by using a conventional semiconductor dicing method with a saw blade. The next stage will be to insert the connecting pins 801 into the through holes 412 . Wire Connections In either embodiment, FIG. 6A or FIG. 7A , similar wire attachment process applies. FIG. 8 is a cross-sectional view 800 illustrating pins 801 attached to contact pads 406 through through holes 412 of the top cover 409 . The pins 801 are first attached to the pads 406 with conductive paste 806 used to secure them to the holes 412 and to the pad 406 . Next, glass paste 802 is used to further secure the pins 801 to the top cover 409 to provide mechanical rigidity of the pins 801 . FIG. 8A is an enlargement 800 A of a portion of FIG. 8 illustrating the conductive paste 806 engaging one end 807 of the pin 801 . Referring to FIGS. 8 and 8A , one end 807 of the platinum pin 801 is dipped into a high temperature conductive paste 806 that cures at a temperature less than the softening point of the glass 803 used for sealing. Alternatively and/or additionally, conductive paste 806 may be spread at the entrance 602 to the through hole 412 of the top cover member 409 . In this fashion, conductive paste 806 can be drawn into the through hole for securing the pin to the through hole 412 . Pin 801 is then inserted into the pin hole 412 until it makes contact with the corresponding pad 406 on the sensor 405 . Each pin 801 is processed similarly. A thin layer 807 of conductive paste may reside between the pins 801 and the contact pads 406 . Sub-assemblies illustrated in FIGS. 8 , and 8 B with the four pins 801 inserted therein are fired to high temperature, which facilitates the bonding of the pins 801 to the contact pads 406 . The sub-assembly is cooled and then another round of glass 802 is applied to each pin 801 , which is then fired to the glass curing temperature. This process offers additional strengthening of the wire connection to the pads 406 , above and beyond securement with just the conductive paste. Reference numeral 804 indicates the volume of hermetically sealed reference cavity 415 . FIG. 8B is a cross-sectional view 800 B similar to FIG. 8 with the pins attached to nickel 805 which partially fills through holes 412 . Nickel 805 may be inserted into through holes 412 so as to partially fill them and engage contact pads 406 . Then, the pins 801 with conductive paste 806 thereon may be brought into engagement with the contact pads. Conductive paste secures the contact pins 801 to the nickel. A thin layer 807 of conductive paste may reside between the pins 801 and the nickel 805 . FIG. 8C is an enlargement 800 C of a portion of FIG. 8 B. FIG. 8D is a view 800 D of an enlargement similar to FIG. 8A illustrating the pin 801 in contact with the contact pad 406 . Electroplating methods can be used to plug the holes halfway with nickel, followed by pin attachment to the nickel as described above. The nickel foot pad 805 then makes contact to the sensor pads 406 . Final Packaging Several embodiments for performing the final packaging of the sub-assemblies are disclosed. FIG. 9 is a cross-sectional view 900 of a stainless steel screw housing 901 brazed to a Kovar header 902 at high temperature. Stainless steel screw housing 901 includes exterior threads 903 for attachment to a process connection. Referring to FIG. 9 , a Kovar header 902 is obtained with a hole drilled through the center as shown. The back end 905 of the Kovar header is then inserted into the nose of a stainless steel screw housing as shown. The stainless steel housing 901 and the Kovar header 902 are then brazed at a temperature that will allow complete fusion 904 of the surfaces in contact. This process is the preferred embodiment due to the high temperature required and also the ease it offers for the eventual attachment of the sensor sub-assembly. After that, a sensor sub-assembly such as that illustrated in FIG. 6A is inserted as shown in FIGS. 9 and 10 . FIG. 10 is a cross-sectional view 1000 of the stainless steel-Kovar unit with a sensor sub-assembly inserted into it as shown. Prior to insertion, sealing glass 1001 is applied to the inner surface 906 of the Kovar header 902 . The stainless steel-Kovar unit and the sensor sub-assembly are then fired at the glass cure temperature, which enables the bonding of the two units. Alternatively, the sensor sub-assemblies of FIG. 6A or FIG. 8B can be inserted into the Kovar header. Other designs within the spirit and the scope of the invention as disclosed and claimed may be inserted into a Kovar header. FIG. 11 is a cross-sectional view 1100 of a stainless steel-Kovar unit with a brazed Kovar header and sensor sub-assembly being inserted therein The sensor sub-assembly is attached to the Kovar using the process stated earlier before insertion into the stainless steel screw housing 901 . Arrow 1101 represents the direction of insertion of the Kovar header and the sensor sub-assembly which has been secured to the header into the stainless steel housing by laser jet welding. Laser jet welding is localized welding and doesn't destroy the sensor. Surface 1102 of the header is laser welded to the surface 1103 of the stainless steel housing. It should be noted that the stainless steel housing could be of any shape and is not necessarily cylindrical as shown in FIGS. 9-11 . FIG. 12 is a cross-sectional view 1200 of a double-threaded stainless steel screw housing. Stainless steel screw housing 1201 is designed so that it has inner 1203 and outer threading 1202 as shown. It is known in the art that most glass paste materials do not adhere well to stainless steel. However, this problem is significantly minimized by utilizing geometry to overcome the adhesion problem between glass and stainless steel, which allows the elimination of Kovar, thereby simplifying the process further. The sensor sub-assembly with the pins 1302 is inserted as shown by the arrow 1303 into the stainless steel screw housing 1201 and dropped into the stainless case as shown in FIG. 13 . FIG. 13 is a cross-sectional view 1300 of a double-threaded stainless steel screw housing 1201 together with the sensor sub-assembly inserted therein encased by a glass seal 1301 . Sealing glass 1301 is applied into the case and cured. Since the glass flows conformally with the inner threading 1203 of the stainless steel case before curing, it will retain the molded shape when cooled. This process provides intimate contact between glass 1301 and stainless 1201 but does not require that the two surfaces be chemically bonded. The degree of leakage will strongly depend on the number of threads and height of the threaded section. More threads and increased height will provide a tortuous path for gases which will attempt to leak from the sensor sub-assembly where the pressure is sensed. Those skilled in the art will readily recognize that changes to FIGS. 12 and 13 may be made such that the sensor sub-assembly may be encased by a larger and longer stainless steel housing such that the sensor would be encased by more glass. Further, those skilled in the art will readily recognize that more and different thread patterns may be used from that shown in FIGS. 12 and 13 . For instance, a greater number of inner threads 1203 may be utilized or they may be less coarse so as to create a more tortuous path so as to prohibit the escape of process gasses from the final packaging. It is recommended that a glass seal length 10 times the thickness of the sensor sub-assembly be used. FIG. 14 is a cross-sectional view 1400 of a double-threaded stainless steel screw housing 1401 with a ceramic tube 1402 placed therein. Braze material 1405 is placed between the ceramic tube 1402 and interior threads 1407 of the stainless steel screw housing. FIG. 14A is a cross-sectional view 1400 A similar to that of FIG. 14 with a sensor sub-assembly having been inserted into the stainless steel housing 1401 as shown after sliding the pins through ceramic tube 1402 . The blow out stopper of at least 100 mils is machined out of stainless steel housing. Ceramic tube 1402 includes four passageways 1403 for wires of pins 1302 / 801 and another passageway 1410 for a thermocouple lead. The ceramic tube may be made of aluminum nitride or its equivalent, Volume 1408 in FIG. 14 simply indicates the place the sensor sub-assembly occupies. Bottom protection shield 1409 protects the diaphragm of the sensor sub-assembly from engine particulates. A sensor sub-assembly without a bottom housing 407 may be used in the structure of FIG. 14 . Similarly, a sensor sub-assembly without a top cover may be used in the structure of FIG. 14 . And, a sensor alone may be used in the structure of FIG. 14 . Reference numeral 1412 indicates the direction of the insertion of the ceramic tube and sensor in the housing. Referring to FIGS. 14 and 14A , the stainless steel housing 1401 is fabricated as shown. It has both outer 1406 and inner threading 1407 . A ceramic tube, with holes equal to the number of sensor pins 1302 / 801 and one extra hole 1410 for a thermocouple, is inserted into the stainless steel as shown. A high temperature brazing material 1405 is applied in the gap between the ceramic and stainless steel so that it is conformal to the inner thread 1403 of the stainless steel tube. It is ensured that the ceramic tube 1402 touches or engages 1411 the blowout stopper 1404 preventing the ceramic tube from being blown out under pressure should it detach from the stainless steel. The ceramic tube is then brazed to the stainless steel with a high temperature braze material 1405 that brazes at temperature greater than the operating temperature of the device. Pins 1302 of the sensor sub assembly are then inserted into the tube holes 1403 . The section where the ceramic tube intimately contacts the sensor sub-assembly is sealed with high temperature glass. After leak checking, a protection shield 1409 is then attached to protect the diaphragm from being hit by particles in the engine. The protection or particulate shield may be eliminated if the sensor sub-assembly includes the bottom member 407 . FIG. 15 is a cross-sectional view 1500 of a sensor illustrating bump 1501 or stud metal affixed to contact pads 406 on the sensor. Referring to FIG. 15 , additional metallization “bump” 1501 is placed on each of the ohmic contact pads 406 is shown. The bump 1501 is about 5 microns out of plane of the main bonding pads 406 . This is done before dicing the sensors into single chips. The bump serves important functions. It facilitates connection between the sensor ohmic contact 406 and the pins to be eventually attached it. Bumps also eliminate the need for a top cover substrate 409 such as is shown in FIG. 6 . Tubes 1402 made from ceramic such as alumina or aluminum nitride like the one illustrated in FIG. 14 commonly known in the art as ceramic tubes are obtained with through holes equal to the number of contact pads 406 on the sensors, including one for thermocouple insertion. FIG. 16 is a cross-sectional view 1600 of a ceramic tube 1402 having pins 1302 secured therein. Pins 1302 engage the sensor and a bump 1501 or stud metal affixed to contact pads 406 on the sensor 405 . Through holes 1602 corresponding to the contact pads 406 are pre-arranged to align directly on to the top of the corresponding bond pads. Conductive wires 1302 such as nickel or platinum are inserted into the through holes that correspond to the bond pads. Attachment to the bump is secured with a high temperature conductive paste 1603 . Attachment of the wires to the through holes 1602 is accomplished with either conductive or non conductive paste 1604 by the methods described above. Thermocouple hole 1601 receives a thermocouple if one is desired. Attachment of the wires to the ceramic tube is accomplished before attachment of the wires to the sensor chip 405 . The ceramic tube 1402 and the wires inside 1302 are first fired at temperatures above the anticipated operating temperature of the device. Since there is no sensor chip that can be damaged by the high temperature, this process allows the package unit to be ruggedly secured. The face of the ceramic is then smoothened so that the exposed sections of the wires are planar with the surface of the ceramic. It is then attached to the conductive bumps 1501 on the sensor 405 as shown in FIG. 16 and fired at 650° C. to attach the bump to the pins. Conductive paste 1603 may optionally be used for this process. The ceramic tube 1402 with the sensor 405 attached to it is then inserted into a double-threaded stainless steel screw housing similar to that shown in FIG. 12 . FIG. 17 is a cross-sectional view 1700 similar to that of FIG. 14 together with a sensor sub-assembly inserted therein. The inner portion of the screw housing has been pre-wet with high temperature glass paste 1701 before inserting the unit of FIG. 16 . More glass 1702 is then applied to the sensor 405 head area so that a reference cavity 1703 is formed. The entire package is then fired at 800° C. for 30 minutes in nitrogen ambient. The final package looks like the one shown in FIG. 17 . This package is re-workable in that the sensor can be removed and replaced. This can be done by removing the section of glass that is connected to the sensor. After replacement, it is initially fired at low temperature to attach the bump to the pins. Glass 1702 is attached and the package is fired again at 800° C. FIG. 18 is an alternative embodiment 1800 of the sensor 405 in combination with an aluminum nitride top cover 1801 having a nickel transconnect 1802 . FIG. 19 is similar to FIG. 18 and illustrates 1900 the securement of the aluminum nitride top cover 1801 , sensor 405 and aluminum nitride bottom substrate 1805 with glass 1901 . Bottom substrate 1805 includes an aperture 1804 therein. To batch fabricate the package, the through holes in the aluminum nitride top cover are filled with electroplated nickel 1802 such that the nickel footpads will come to rest on the sensor pads as shown in FIGS. 18 and 19 . After bump-attachment between the top cover and the sensor, the bottom cover is then brought in contact with the bottom part of the sensor. The entire unit is then glassed 1901 as illustrated in FIG. 19 by the process described in connection with FIGS. 4 and 5 above. Reference cavity 1902 is formed by glassing 1901 the sensor sub-assembly as illustrated in FIG. 19 . The sensor sub-assembly of FIG. 19 is then inserted into a sensor housing which has been described herein. FIG. 20 is a cross-sectional view 2000 of an aluminum nitride ceramic tube 2002 having bores 2005 therethrough inserted into a long stainless steel tube 2001 to thermally decouple a sensor sub-assembly having a sensor chip and a bottom cover from the tube. FIG. 21 is a cross-sectional view 2100 along the lines 21 — 21 of FIG. 20 . FIG. 22 is a cross-sectional view 2200 along the lines 22 — 22 of FIG. 20 . The package embodiment of FIGS. 20-22 ensures that minimum glass is used in the sealing process. The housing is a stainless steel tube 2001 . Inserted into the tube is the aluminum nitride prefabricated header 2006 . The insertion is made such that the section of the header that will house the sensor 405 extends out of the stainless steel tube far enough so that any thermomechanical effect of the stainless steel 2001 on the aluminum nitride header 2002 does not travel far enough to have an effect on the sensor. As a result, thermomechanical stress decoupling between the sensor and the stainless steel is accomplished. Since the coefficient of thermal expansion of the silicon carbide sensor and the aluminum nitride header are practically the same, very little stress is induced on the sensor by the package components. The outer surface 2009 of the aluminum nitride header 2002 is coated with a metallic material such as nickel. The nickel will be use for laser welding or brazing to the stainless steel to prevent any leak between the stainless steel and the aluminum nitride. Reference numeral 2005 indicates through holes in the aluminum nitride header. Reference numeral 2004 represents the volume of the reference cavity which will formed upon the insertion of a sensor in sensor cavity 2007 and glassing the sensor sub-assembly to the header. Reference numeral 2003 represents the length of the extension of the header 2002 outside of the stainless steel tube 2001 . Conductive paste 2008 is applied around the four holes located at the cavity base of the aluminum nitride header 2002 . Connecting pins are then inserted from the cavity side of the header and extended so that the conductive paste wets them. When fired at high temperature, the pins will adhere to the now cured and hardened paste. The hardened paste will also adhere strongly to the aluminum nitride, thereby providing a strong mechanical anchor to the pins. A smaller amount of conductive paste is reapplied on the surfaces of the hardened paste. The sensor is then inserted into the receiving cavity 2007 in the header so that the sensor pads are aligned to the conductive paste and brought in intimate contact. Another high temperature curing is performed to allow the paste to bond to the sensor pads, thereby establishing electrical communication between the sensor, pins, and outside circuitry. High temperature glass fills the small gap between the sensor sub-assembly having only a sensor 405 and a bottom cover 407 or just a sensor 405 and the inner wall of the cavity 2007 of the aluminum nitride header. The glass is then fired at high temperature so that it bonds to the aluminum nitride and the sensor, thereby sealing that section and preventing leakage. As a result of these processes, namely, glass curing and conductive paste curing, an air bubble is trapped inside the reference cavity. This acts as reference pressure for the transducer. Although this invention has been described by way of example and with particularity and specificity, those skilled in the art will recognize that many changes and modifications may be made without departing from the spirit and scope of the invention defined by the claims which follow hereinbelow.

Methods of bulk manufacturing high temperature sensor sub-assembly packages are disclosed and claimed. Sensors are sandwiched between a top cover and a bottom cover so as to enable the peripheries of the top covers, sensors and bottom covers to be sealed and bound securely together are disclosed and claimed. Sensors are placed on the bottom covers leaving the periphery of the bottom cover exposed. Likewise, top covers are placed on the sensors leaving the periphery of the sensor exposed. Individual sensor sub-assemblies are inserted into final packaging elements which are also disclosed and claimed. Methods of directly attaching wires or pins to contact pads on the sensors are disclosed and claimed. Sensors, such as pressure sensors and accelerometers, and headers made out of silicon carbide and aluminum nitride are disclosed and claimed. Reference cavities are formed in some embodiments disclosed and claimed herein where top covers are not employed.

FIELD OF THE INVENTION [0001] This invention relates to methods and devices for the treatment of vascular aneurysms and other comparable vascular abnormalities. More particularly, this invention relates to occlusion devices for vascular aneurysms that comprise a reticulated elastomeric matrix structure and a delivery device. BACKGROUND OF THE INVENTION [0002] The cardio-vascular system, when functioning properly, supplies nutrients to all parts of the body and carries waste products away from these parts for elimination. It is essentially a closed-system comprising the heart, a pump that supplies pressure to move blood through the blood vessels, blood vessels that lead away from the heart, called arteries, and blood vessels that return blood toward the heart, called veins. On the discharge side of the heart is a large blood vessel called the aorta from which branch many arteries leading to all parts of the body, including the organs. As the arteries get close to the areas they serve, they diminish to small arteries, still smaller arteries called arterioles, and ultimately connect to capillaries. Capillaries are minute vessels where outward diffusion of nutrients, including oxygen, and inward diffusion of wastes, including carbon dioxide, takes place. Capillaries connect to tiny veins called venules. Venules in turn connect to larger veins which return the blood to the heart by way of a pair of large blood vessels called the inferior and superior venae cava. [0003] As shown in FIG. 1 , arteries 2 and veins comprise three layers known as tunics. An inner layer 4 , called the tunica interna, is thin and smooth, constituted of endothelium, and rests on a connective tissue membrane rich in elastic and collagenous fibers that secrete biochemicals to perform functions such as prevention of blood clotting by inhibiting platelet aggregation and regulation of vasoconstriction and vasodilation. A middle layer 6 called the tunica media is made of smooth muscle 8 and elastic connective tissue 10 and provides most of the girth of the blood vessel. A thin outer layer 12 , called the tunica adventitia, formed of connective tissue secures the blood vessel to the surrounding tissue. [0004] The tunica media 6 differentiates an artery from a vein in that it is thicker in an artery to withstand the higher blood pressure exerted by the heart on the walls of the arteries. Tough elastic connective tissue provides an artery 2 sufficient elasticity to withstand the blood pressure and sudden increases in blood volume that occur with ventricular contractions. [0005] When the wall of an artery, especially the tunica media 6 of that wall, has a weakness, the blood pressure can dilate or expand the region of the artery 2 with the weakness, and a pulsating sac 14 called a berry or saccular aneurysm ( FIG. 2 ), can develop. If the walls of the arteries 2 expand around the circumference of the artery 2 , this is called a fusiform aneurysm 16 ( FIG. 3 ). If the weakness causes a longitudinal tear in the tunica media of the artery, it is called a dissecting aneurysm. Saccular aneurysms are common at artery bifurcations 18 ( FIGS. 4 and 5 ) located around the brain. Dissecting aneurysms are common in the thoracic and abdominal aortas. The pressure of an aneurysm against surrounding tissues, especially the pulsations, may cause pain and may also cause tissue damage. However, aneurysms are often asymptomatic. The blood in the vicinity of the aneurysm can become turbulent, leading to formation of blood clots, that may be carried to various body organs where they may cause damage in varying degrees, including cerebrovascular incidents, myocardial infarctions and pulmonary embolisms. Should an aneurysm tear and begin to leak blood, the condition can become life threatening, sometimes being quickly fatal, in a matter of minutes. [0006] Because there is relatively little blood pressure in a vein, venous “aneurysms” are non-existent. Therefore, the description of the present invention is related to arteries, but applications within a vein, if useful, are to be understood to be within the scope of this invention. [0007] The causes of aneurysms are still under investigation. However, researchers have identified a gene associated with a weakness in the connective tissue of blood vessels that can lead to an aneurysm. Additional risk factors associated with aneurysms such as hyperlipidemia, atherosclerosis, fatty diet, elevated blood pressure, smoking, trauma, certain infections, certain genetic disorders, such as Marfan's Syndrome, obesity, and lack of exercise have also been identified. Cerebral aneurysms frequently occur in otherwise healthy and relatively youthful people and have been associated with many untimely deaths. [0008] Aneurysms, widening of arteries caused by blood pressure acting on a weakened arterial wall, have occurred ever since humans walked the planet. In recent times, many methods have been proposed to treat aneurysms. For example, Greene, Jr., et al., in U.S. Pat. No. 6,165,193 propose a vascular implant formed of a compressible foam hydrogel that has a compressed configuration from which it is expansible into a configuration substantially conforming to the shape and size of a vascular malformation to be embolized. Greene's hydrogel lacks the mechanical properties to enable it to regain its size and shape in vivo were it to be compressed for catheter, endoscope, or syringe delivery, and the process can be complex and difficult to implement. Other patents disclose introduction of a device, such as a stent or balloon (Naglreiter et al., U.S. Pat. No. 6,379,329) into the aneurysm, followed by introduction of a hydrogel in the area of the stent to attempt to repair the defect (Sawhney et al., U.S. Pat. No. 6,379,373). [0009] Still other patents suggest the introduction into the aneurysm of a device, such as a stent, having a coating of a drug or other bioactive material (Gregory, U.S. Pat. No. 6,372,228). Other methods include attempting to repair an aneurysm by introducing via a catheter a self-hardening or self-curing material into the aneurysm. Once the material cures or polymerizes in situ into a foam plug, the vessel can be recanalized by placing a lumen through the plug (Hastings, U.S. Pat. No. 5,725,568). [0010] Another group of patents relates more specifically to saccular aneurysms and teaches the introduction of a device, such as string, wire or coiled material (Boock U.S. Pat. No. 6,312,421), or a braided bag of fibers (Greenhalgh, U.S. Pat. No. 6,346,117) into the lumen of the aneurysm to fill the void within the aneurysm. The device introduced can carry hydrogel, drugs or other bioactive materials to stabilize or reinforce the aneurysm (Greene Jr. et al., U.S. Pat. No. 6,299,619). [0011] Another treatment known to the art comprises catheter delivery of platinum microcoils into the aneurysm cavity in conjunction with an embolizing composition comprising a biocompatible polymer and a biocompatible solvent. The deposited coils or other non-particulate agents are said to act as a lattice about which a polymer precipitate grows thereby embolizing the blood vessel (Evans et al., U.S. Pat. No. 6,335,384). [0012] It is an understanding of the present invention that such methods and devices suffer a variety of problems. For example, if an aneurysm treatment is to be successful, any implanted device must be present in the body for a long period of time, and must therefore be resistant to rejection, and not degrade into materials that cause adverse side effects. While platinum coils may be have some benefits in this respect, they are inherently expensive, and the pulsation of blood around the aneurysm may cause difficulties such as migration of the coils, incomplete sealing of the aneurysm, or fragmentation of blood clots. It is also well known that the use of a coil is frequently associated with recanalization of the site, leading to full or partial reversal of the occlusion. If the implant does not fully occlude the aneurysm and effectively seal against the aneurysm wall, pulsating blood may seep around the implant and the distended blood vessel wall causing the aneurysm to reform around the implant. [0013] The delivery mechanics of many of the known aneurysm treatment methods can be difficult, challenging, and time consuming. [0014] Most contemporary vascular occlusion devices, such as coils, thrombin, glue, hydrogels, etc., have serious limitations or drawbacks, including, but not limited to, early or late recanalization, incorrect placement or positioning, migration, and lack of tissue ingrowth and biological integration. Also, some of the devices are physiologically unacceptable and engender unacceptable foreign body reactions or rejection. In light of the drawbacks of the known devices and methods, there is a need for more effective aneurysm treatment that produces permanent biological occlusion, can be delivered in a compressed state through small diameter catheters to a target vascular or other site with minimal risk of migration, will prevent the aneurysm from leaking or reforming. OBJECTS OF THE INVENTION [0015] It is an object of this invention to provide a method and device for the treatment of vascular aneurysms. [0016] It is also an object of this invention to provide a method and device for occluding cerebral aneurysms. [0017] It is a further object of the invention to provide a method and device for occluding cerebral aneurysms by bio-integrating and sealing off the aneurysm to prevent migration, recanalization, leaking, or reforming. [0018] It is a yet further object of this invention to provide a method and device for occluding vascular aneurysms wherein the device comprises a reticulated elastomeric matrix structure and a delivery device. [0019] It is a yet further object of this invention to provide a system for treating cerebral aneurysms that comprises a reticulated elastomeric matrix structure and a delivery device. [0020] It is a yet further object of the invention to provide an implant for occluding a cerebral aneurysm that comprises a reticulated elastomeric matrix structure that compresses for delivery and expands upon deployment in an aneurysm to cause angiographic occlusion. [0021] These and other objects of the invention will become more apparent in the discussion below. SUMMARY OF THE INVENTION [0022] According to the invention an aneurysm treatment device is provided for in situ treatment of aneurysms, particularly, cerebral aneurysms, in mammals, especially humans. The treatment device comprises a resiliently collapsible implant comprised of a reticulated, biodurable elastomeric matrix, which is collapsible from a first, expanded configuration wherein the implant can support the wall of an aneurysm to a second collapsed configuration wherein the collapsible implant is deliverable into the aneurysm, for example, by being loadable into a catheter and passed through the patient's vasculature. Pursuant to the invention, useful aneurysm treatment devices can have sufficient resilience, or other mechanical property, including expansion, to return to an expanded configuration within the space of the aneurysm and to occlude the aneurysm. Preferably, the implant is configured so that hydraulic forces within the aneurysm coupled with recovery and resilience characteristics of the reticulated elastomeric matrix tend to urge the implant against the aneurysm wall. [0023] In another embodiment of the invention, an implant comprises one or more flexible, connected, preferably spherically-, ellipsoidally-, or cylindrically-shaped structures that are positioned in a compressed state in a delivery catheter. The connected structures preferably have spring coils on each end, one of which coils is releasably secured within the delivery catheter. A longitudinally extending rod or wire that acts to assist in pushing the implant distally extends through the structures and is withdrawn during delivery. The implant tends to form a spiral shape after delivery. [0024] In another embodiment of the invention an implant that is initially essentially cylindrical in shape in connection with a delivery catheter comprises a mechanism such that when the structure is positioned at a desired location, the mechanism is engaged to cause the structure to assume any particular shape that will occlude an aneurysm. [0025] In another embodiment of the invention, an implant for occlusion of an aneurysm comprises reticulated elastomeric matrix in a shape that can be compressed, can be inserted into a delivery catheter, can be ejected or deployed from the delivery catheter into an aneurysm, and can then expand to sufficient size and shape to occlude the aneurysm. Examples of such shapes include, but are not limited to, spheres, hollow spheres, cylinders, hollow cylinders, noodles, cubes, pyramids, tetrahedrons, hollow cylinders with lateral slots, trapezoids, parallelepipeds, ellipsoids, rods, tubes, or elongated prismatic forms, folded, coiled, helical or other more compact configurations, segmented cylinders where “sausage-like” segments have been formed, flat square or rectangular shapes, daisy shapes, braided shapes, or flat spiral shapes, optionally with surgical suture or radiopaque wire support extending therein. [0026] Although multiple implants can be deployed, used or implanted, it is a feature of one aspect of the present invention that preferably a single implant fills an aneurysm, effectively a “single shot” occlusion. It is contemplated, in one embodiment, that even when their pores become partially filled or completely filled with biological fluids, bodily fluids and/or tissue in the course of time or immediately after delivery, and/or the implants are either still partially compressed or partially recovered after delivery, such implantable device or devices for vascular malformation applications have a volume of at least about 50% of the aneurysm volume. The ratio of implant (or implants) volume to aneurysm volume is defined as packing density. In another embodiment, such implantable device or devices for vascular malformation applications have a volume of at least about 75% of the aneurysm volume. In another embodiment, such implantable device or devices for vascular malformation applications have a volume of at least about 125% of the aneurysm volume. In another embodiment, such implantable device or devices for vascular malformation applications have a volume of at least about 175% of the aneurysm volume. In another embodiment, such implantable device or devices for vascular malformation applications have a volume of at least about 200% of the aneurysm volume. In another embodiment, such implantable device or devices for vascular malformation applications have a volume of at least about 300% of the aneurysm volume. In another embodiment, such implantable device or devices for vascular malformation applications have a volume of at least about 400% of the aneurysm volume. [0027] The packing density is targeted to achieve angiographic occlusion after embolization of the aneurysm by the implant, followed by clotting, thrombosis, and tissue ingrowth, ultimately leading to biological obliteration of the aneurysm sac. Permanent tissue ingrowth will prevent any possible recanalization. [0028] It is furthermore preferable that the implant be treated or formed of a material that will encourage such fibroblast immigration. It is also desirable that the implant be configured, with regard to its three-dimensional shape, and its size, resiliency and other physical characteristics, and be suitably chemically or biochemically constituted to foster eventual tissue ingrowth and formation of scar tissue that will help fill and/or obliterate the aneurysm sac. [0029] The aneurysm treatment device preferably comprises a reticulated biodurable elastomeric matrix or the like that is capable of being compressed and inserted into a catheter for implantation. In another embodiment, the implant can be formed of a partially hydrophobic reticulated biodurable elastomeric matrix having its pore surfaces coated to be partially hydrophilic, for example, by being coated with at least a partially hydrophilic material, optionally a partially hydrophilic reticulated elastomeric matrix. Preferably the entire foam has such a hydrophilic coating throughout the pores of the reticulated elastomeric matrix. [0030] In one embodiment, the hydrophilic material carries a pharmacologic agent, for example, elastin to foster fibroblast proliferation. It is also within the scope of the invention for the pharmacologic agent to include sclerotic agents, inflammatory induction agents, growth factors capable of fostering fibroblast proliferation, or genetically engineered an/or genetically acting therapeutics. The pharmacologic agent or agents preferably are dispensed over time by the implant. Incorporation of biologically active agents in the hydrophilic phase of a composite foam suitable for use in the practice of the present invention is described in co-pending, commonly assigned U.S. patent applications Ser. No. 10/692,055, filed Oct. 22, 2003, Ser. No. 10/749,742, filed Dec. 30, 2003, Ser. No. 10/848,624, filed May 17, 2004, and Ser. No. 10/900,982, filed Jul. 27, 2004, each of which is incorporated herein by reference in its entirety. [0031] In another aspect, the invention provides a method of treating an aneurysm comprising the steps of: [0032] (a) imaging an aneurysm to be treated to determine its size and topography; [0033] (b) selecting an aneurysm treatment device according to the invention for use in treating the aneurysm; and [0034] (c) implanting the aneurysm treatment device into the aneurysm. [0035] Preferably, the method further comprises: [0036] (d) loading the aneurysm treatment device into a catheter or other delivery means; [0037] (e) threading the catheter through an artery to the aneurysm; and [0038] (f) positioning and releasing the aneurysm treatment device in the aneurysm. [0039] Once an aneurysm has been identified using suitable imaging technology, such as a magnetic resonance image (MRI), computerized tomography scan (CT Scan), x-ray imaging with contrast material or ultrasound, and is to be treated, the surgeon chooses which implant he or she feels would best suit the aneurysm, both in shape and size. The implant can be used alone. In another embodiment, the aneurysm treatment device of the invention may also be used in conjunction with a frame of platinum coils to assist in reducing or eliminating the risk of implant migration out of the neck of the aneurysm. This is particularly true in the case of wide neck or giant aneurysms. The chosen implant is then loaded into an intravascular catheter in a compressed state. If desired, the implant can be provided in a sterile package in a pre-compressed configuration, ready for loading into a catheter. Alternatively, the implants can be made available in an expanded state, also, preferably, in a sterile package, and the surgeon at the site of implantation can use a suitable secondary device or a loader apparatus to compress an implant so that it can be loaded into a delivery catheter. [0040] With an implant loaded into the catheter, the catheter is advanced through an artery to the diseased portion of the affected artery using any suitable technique known in the art. By use of the catheter the implant is then inserted and positioned within the aneurysm. As the implant is released from the catheter, where it is in its compressed state, it expands and is manipulated into a suitable position within the aneurysm. BRIEF DESCRIPTION OF THE DRAWINGS [0041] One or more embodiments of the invention and of making and using the invention, as well as the best mode contemplated of carrying out the invention, are described in detail below, by way of example, with reference to the accompanying drawings, in which: [0042] FIG. 1 is a side view of an artery with layers partially cut away to illustrate the anatomy of the artery; [0043] FIG. 2 is a longitudinal cross-section of an artery with a saccular aneurysm; [0044] FIG. 3 is a longitudinal cross-section of an artery with a fusiform aneurysm; [0045] FIG. 4 is a top view of an artery at a bifurcation; [0046] FIG. 5 is a top view of an artery at a bifurcation with a saccular aneurysm at the point of bifurcation; [0047] FIGS. 6 to 8 illustrate an embodiment of the invention wherein a segmented vascular occlusion device is deployed; [0048] FIGS. 9 and 10 illustrate a further embodiment of the invention where a vascular occlusion device is fixed in position; and [0049] FIGS. 11 to 17 B represent embodiments of implants useful according to the invention. DETAILED DESCRIPTION OF THE INVENTION [0050] The present invention relates to a system and method for treating aneurysms, particularly cerebral aneurysms, in situ. As will be described in detail below, the present invention provides an aneurysm treatment device comprising a reticulated, biodurable elastomeric matrix implant designed to be permanently inserted into an aneurysm with the assistance of an intravascular catheter. Reticulated matrix, from which the implants are made, has sufficient and required liquid permeability and thus selected to permit blood, or other appropriate bodily fluid, and cells and tissues to access interior surfaces of the implants. This happens due to the presence of inter-connected and inter-communicating, reticulated open pores and/or voids and/or channels that form fluid passageways or fluid permeability providing fluid access all through. The implants described in detail below can be made in a variety of sizes and shapes, the surgeon being able to choose the best size and shape to treat a patient's aneurysm. Once inserted the inventive aneurysm treatment device or implant is designed to cause angiographic occlusion, followed by clotting, thrombosis, and eventually bio-integration through tissue ingrowth and proliferation. Furthermore, the inventive aneurysm treatment device can carry one or more of a wide range of beneficial drugs and chemical moieties that can be released at the affected site for various treatments, such as to aid in healing, foster scarring of the aneurysm, prevent further damage, or reduce risk of treatment failure. With release of these drugs and chemicals locally, employing the devices and methods of the invention, their systemic side effects are reduced. [0051] An implant or occlusion device according to the invention can comprise a reticulated biodurable elastomeric matrix or other suitable material and can be designed to be inserted into an aneurysm through a catheter. A preferred reticulated elastomeric matrix is a compressible, lightweight material, designed for its ability to expand within the aneurysm without expanding too much and tearing the aneurysm. Although multiple implants can be deployed, used or implanted, preferably a single implant should fill the aneurysm to achieve angiographic occlusion. It is contemplated, in one embodiment, that even when their pores become partially filled or completely filled with biological fluids, bodily fluids and/or tissue in the course of time or immediately after delivery, and/or the implants are either still partially compressed or partially recovered after delivery, such implantable device or devices for vascular malformation applications have a volume of at least about 50% of the aneurysm volume. The ratio of implant (or implants) volume to aneurysm volume is defined as packing density. In another embodiment, such implantable device or devices for vascular malformation applications have a volume of at least about 75% of the aneurysm volume. In another embodiment, such implantable device or devices for vascular malformation applications have a volume of at least about 125% of the aneurysm volume. In another embodiment, such implantable device or devices for vascular malformation applications have a volume of at least about 175% of the aneurysm volume. In another embodiment, such implantable device or devices for vascular malformation applications have a volume of at least about 200% of the aneurysm volume. In another embodiment, such implantable device or devices for vascular malformation applications have a volume of at least about 300% of the aneurysm volume. In another embodiment, such implantable device or devices for vascular malformation applications have a volume of at least about 400% of the aneurysm volume. Insertion of the implant followed by tissue ingrowth should result in total obliteration of the aneurysm sac. [0052] Employment of an implant that can support invasion of fibroblasts and other cells enables the implant to eventually become a part of the healed aneurysm. Elastin can also be coated onto the implant providing an additional route of clot formation. [0053] The implant can also contain one or more radiopaque markers for visualization by radiography or ultrasound to determine the orientation and location of the implant within the aneurysm sac. Preferably plantinum markers are incorporated in the implant and/or relevant positions of delivery members. [0054] If desired, the outer surfaces of the implant or occlusion device can be coated, after fabrication of the implant or occlusion device with functional agents, such as those described herein, optionally employing an adjuvant that secures the functional agents to the surfaces and to reticulated elastomeric matrix pores adjacent the outer surfaces, where the agents will become quickly available. Such external coatings, which may be distinguished from internal coatings provided within and preferably throughout the pores of reticulated elastomeric matrix used, may comprise fibrin and/or other agents to promote fibroblast growth. [0055] Once an aneurysm has been identified using suitable imaging technology, such as a magnetic resonance image (MRI), computerized tomography scan (CT Scan), x-ray imaging with contrast material or ultrasound, the surgeon chooses which implant he or she feels would best suit the aneurysm, both in shape and size. The chosen implant is then loaded into an intravascular catheter in a compressed state. The implants can be sold in a sterile package containing a pre-compressed implant that is loaded into a delivery catheter. Alternatively, the implant can be sold in a sterile package in an expanded state, and the surgeon at the site of implantation can use a device, e.g. a ring, funnel or chute that compresses the implant for loading into the catheter. [0056] Once the implant is loaded into the catheter, the catheter is then advanced through an artery to the diseased portion of the affected artery using any of the techniques common in the art. Using the catheter the implant is then inserted and positioned within the aneurysm. Once the implant is released from its compressed state, it is allowed to expand within the aneurysm. [0057] When properly located in situ, pursuant to the teachings of this invention, implants or occlusion devices are intended to cause angiographic occlusion of the aneurysm sac. The presence of implants or occlusion devices, optionally including one or more pharmacologic agents borne on each implant, stimulates fibroblast proliferation, growth of scar tissue around the implants and eventual immobilization of the aneurysm. [0058] Advantageously, the implants of the invention can, if desired, comprise reticulated biodurable elastomeric implants having a materials chemistry and microstructure as described herein. [0059] The invention can perhaps be better appreciated from the drawings. In the embodiment of the invention shown in FIGS. 6 to 8 , a foam structure 50 comprises two or more sections 52 , preferably from about 2 to about 100, that are defined by radiopaque rings, e.g., platinum rings or compression members 54 or similar mechanisms. Foam sections 52 comprise a longitudinally extending flexible mesh 58 defining a lumen 62 . A distal spring section 64 attached to the distal end 66 of structure 50 comprises a distal tip 68 and a lumen 70 in communication with lumen 62 . At the proximal end 74 of structure 50 a proximal spring 72 is attached to proximal end 74 and has a lumen 76 extending therethrough. A flexible but rigid wire 78 extends through lumen 76 , lumen 62 , and lumen 70 . Wire 78 has a radiopague tip marker 60 . Flexible mesh 58 extends distally as a jacket to cover coil 64 and proximally as a jacket to cover coil 72 . [0060] Compressed structure 50 is positioned within a delivery catheter 80 that has a longitudinally extending lumen 82 and a distal radiopaque marker 86 . The proximal end 88 of catheter 80 has a narrowed opening 90 that slidably engages a pushing catheter 94 . [0061] The proximal end 96 of pushing catheter 94 slidably engages the proximal section 98 of wire 78 . The distal end 102 of pushing catheter 94 comprises a radiopaque marker 104 and an opening 106 . A flexible loop or wire 108 attached to coil 76 extends through opening 106 to engage wire 78 . [0062] To deploy structure 50 , as shown in FIG. 7 , pusher catheter 94 and wire 78 are advanced distally. As portions of structure 50 extend distally past the distal end 110 of delivery catheter 80 , wire 78 is withdrawn in the proximal direction. Eventually, as shown in FIG. 8 , wire 78 is withdrawn past opening 106 so that flexible wire 108 releases and structure 50 is free from delivery catheter 80 . [0063] Preferably coils 70 and 76 and mesh 58 comprise a biocompatible shape memory alloy or polymer such as nitinol, so that the released structure will assume a non-linear, preferably helical or irregular, shape. [0064] It should be appreciated that in the aspect of the invention shown in FIG. 7 the implant is still connected to the delivery “system” via connecting number 108 . This is important because the implant can in this partially delivered condition be maneuvered within the patient to either reposition the implant to optimize placement allowing for a controlled delivery, or even to withdraw or retrieve the implant altogether. [0065] Another embodiment of the invention, a shown in FIGS. 9 and 10 , comprises a delivery catheter 130 and a vascular occlusion device 132 positioned at the distal end 134 of catheter 130 . Extending within a lumen 136 of catheter 130 and through a lumen formed by a coil 138 in occlusion device 132 is a delivery member 140 that has a distal section 142 , a middle section 144 , and a proximal section 146 . A guidewire 150 extends through lumen 152 formed within delivery member 140 . [0066] Coil 138 is wound from one single nitinol wire but it has sections with two different diameters. Coil proximal end 154 and coil distal end 156 , which are like two “nuts”, each have the same diameter, corresponding to and able to engage the diameter of delivery member middle section 144 . The center part of coil 138 has larger a diameter, so that delivery member 140 can move through it freely. To attach occlusion device 132 in a delivery position, it needs to be stretched from a spherical or ball shape into a low profile cylindrical shape by use of a stretching device (not shown). Once device 132 is stretched, it can be locked by inserting delivery member 140 with distal section 142 and engaging proximal nut 154 and distal nut 156 by screw segment 144 to remain in a stretched position for delivery. [0067] For deployment, occlusion device 132 can be released by rotating section 144 proximally catheter 130 . As soon as section 144 unscrews from distal nut 156 into the center part of coil 138 , the memory force of coil 138 will start compressing back to a sphical or ball shape, as shown iin FIG. 10 , while section 144 moves proximally from proximal nut 154 . Detachment will occur after section 144 unscrews completely from proximal nut 154 of coil 138 and soft distal tip 142 is pulled back into catheter 130 . Occlusion device 132 is then released from delivery member 140 at a desired location. [0068] Occlusion device 132 comprises shape memory metallic or polymeric members 158 , preferably nitinol, to which a foam layer 160 is attached. [0069] In FIG. 11 , an implant 182 is formed from a foam member 184 optionally having a round, square, ellipsoidal, or rectangular cross-section. Radiopaque, preferably platinum, markers 186 are positioned or crimped every about 2 to about 10 mm to form a chain or noodle-like structure. Implant 182 has a surgical suture, preferably bio-absorbable, or platinum wire 190 as an internal core through the entire length of the implant to prevent implant 182 from breaking or fragmenting, to provide support for pulling and/or pushing during delivery or deployment, and to prevent over-compaction or unintended packing during delivery or deployment. The length of implant 182 could be from about 5 mm to about 800 mm, preferably from about 50 mm to about 600 mm, and the diameter or effective diameter could be from about 0.25 mm to about 10 mm, preferably from about 0.50 mm to about 2 mm. [0070] The implant 192 in FIG. 12 comprises 2 or more, preferably from about 3 to 6, cylindrical or string segments 194 that have been banded together for structural integrity for delivery or deployment or to be blended with other components. As with implant 182 , radiopaque markers 196 are crimped from about 2 to about 10 mm apart. The length and effective diameter of implant 192 are approximately the same as those of implant 182 . [0071] The implant 198 shown in FIGS. 13A and 13B comprises a flat, preferably square or rectangular, member 200 that can be rolled up to fit in a delivery catheter (not shown). Member 200 preferably has surgical sutures, optionally absorbable, or radiopaque wire 202 sewn around the outer edges 204 and also diagonally 206 . As shown in FIG. 13B , implant 198 can be rolled up to fit within a lumen of a delivery catheter. Upon deployment implant 198 would unroll to fill an aneurysm sac. An advantage of this particular embodiment is the relatively large surface area that is available for occlusion. It is anticipated that implant 198 could be from about 0.25 mm to about 3 mm in thickness and from about 1 mm to about 50 mm in length on the lateral edges. [0072] FIG. 14 represents an implant 210 where a thin string structure 212 has been cut from a flat member 214 . Structure 212 is similar to implant 182 but with or without the internal suture or wire member. Manufacturing implant 210 in this manner provided memory support without nitinol support. [0073] FIGS. 15A and 15B represent structures that may have an unexpanded shape, for example, cylindrical shape 218 , that expands to an expanded shape, for example, spherical shape 220 , due to internal frames (not shown). The outer surface 222 of shape 220 could comprise coils or braids, for example, or different shapes can be sutured together using coils and/or patches to provide maximum surface area for occlusion. [0074] Implant 224 shown in FIGS. 16A and 16B is representative of a nitinol or other shape-memory wire member 226 having a foam cover 228 . Implant 224 is compressed for delivery, as shown in FIG. 16A , and then expands to the configuration shown in FIG. 16B upon deployment. [0075] A cylindrically-shaped implant 230 with slots 232 is shown in FIGS. 17A and 17B . As can be appreciated in the radial cross-section of FIG. 17B , implant 230 may have one or more radiopaque bend markers 234 . An advantage of this shape is that the slots permit the implant to bend to maximize surface area during deployment. [0076] Examples of such shapes include, but are not limited to, spheres, hollow spheres, cylinders, hollow cylinders, noodles, cubes, pyramids, tetrahedrons, hollow cylinders with lateral slots, trapezoids, parallelepipeds, ellipsoids, rods, tubes, or elongated prismatic forms, folded, coiled, helical or other more compact configurations, segmented cylinders where “sausage-like” segments have been formed, flat square or rectangular shapes, daisy shapes, braided shapes, or flat spiral shapes, optionally with surgical suture or radiopaque wire support extending therein. [0077] Certain embodiments of the invention comprise porous, reticulated biodurable elastomeric implants, which are also compressible and exhibit resilience in their recovery, that have a diversity of applications and can be employed, by way of example, in management of vascular malformations, such as for aneurysm control, arteriovenous malfunction, arterial embolization or other vascular abnormalities, or as substrates for pharmaceutically-active agent, e.g., for drug delivery. Thus, as used herein, the term “vascular malformation” includes but is not limited to aneurysms, arteriovenous malfunctions, arterial embolizations and other vascular abnormalities. Other embodiments include reticulated, biodurable elastomeric implants for in vivo delivery via catheter, endoscope, arthroscope, laparoscope, cystoscope, syringe or other suitable delivery-device and can be satisfactorily implanted or otherwise exposed to living tissue and fluids for extended periods of time, for example, at least 29 days. [0078] There is a need in medicine, as recognized by the present invention, for atraumatic implantable devices that can be delivered to an in vivo patient site, for example a site in a human patient, that can occupy that site for extended periods of time without being harmful to the host. In one embodiment, such implantable devices can also eventually become biologically integrated, e.g., ingrown with tissue. Various implants have long been considered potentially useful for local in situ delivery of biologically active agents and more recently have been contemplated as useful for control of endovascular conditions including potentially life-threatening conditions such as cerebral and aortic abdominal aneurysms, arterio venous malfunction, arterial embolization or other vascular abnormalities. [0079] It would be desirable to have an implantable system which, e.g., can optionally cause immediate thrombotic response leading to clot formation, and eventually lead to fibrosis, i.e., allow for and stimulate natural cellular ingrowth and proliferation into vascular malformations and the void space of implantable devices located in vascular malformations, to stabilize and possibly seal off such vascular abnormalities in a biologically sound, effective and lasting manner. [0080] In one embodiment of the invention, cellular entities such as fibroblasts and tissues can invade and grow into a reticulated elastomeric matrix. In due course, such ingrowth can extend into the interior pores and interstices of the inserted reticulated elastomeric matrix. Eventually, the elastomeric matrix can become substantially filled with proliferating cellular ingrowth that provides a mass that can occupy the site or the void spaces in it. The types of tissue ingrowth possible include, but are not limited to, fibrous tissues and endothelial tissues. [0081] In another embodiment of the invention, the implantable device or device system causes cellular ingrowth and proliferation throughout the site, throughout the site boundary, or through some of the exposed surfaces, thereby sealing the site. Over time, this induced fibrovascular entity resulting from tissue ingrowth can cause the implantable device to be incorporated into the aneurysm wall. Tissue ingrowth can lead to very effective resistance to migration of the implantable device over time. It may also prevent recanalization of the aneurysm. In another embodiment, the tissue ingrowth is scar tissue which can be long-lasting, innocuous and/or mechanically stable. In another embodiment, over the course of time, for example, for from 2 weeks to 3 months to 1 year, implanted reticulated elastomeric matrix becomes completely filled and/or encapsulated by tissue, fibrous tissue, scar tissue or the like. [0082] The invention has been described herein with regard to its applicability to aneurysms, particularly cerebral aneurysms. It should be appreciated that the features of the implantable device, its functionality, and interaction with an aneurysm cavity, as indicated above, can be useful in treating a number of arteriovenous malformations (“AVM”) or other vascular abnormalities. These include AVMs, anomalies of feeding and draining veins, arteriovenous fistulas, e.g., anomalies of large arteriovenous connections, abdominal aortic aneurysm endograft endoleaks (e.g., inferior mesenteric arteries and lumbar arteries associated with the development of Type II endoleaks in endograft patients). [0083] Shaping and sizing can include custom shaping and sizing to match an implantable device to a specific treatment site in a specific patient, as determined by imaging or other techniques known to those in the art. In particular, one or at least two comprise an implantable device system for treating an undesired cavity, for example, a vascular malformation. [0084] Some materials suitable for fabrication of the implants according to the invention will now be described. Implants useful in this invention or a suitable hydrophobic scaffold comprise a reticulated polymeric matrix formed of a biodurable polymer that is elastomeric and resiliently-compressible so as to regain its shape after being subjected to severe compression during delivery to a biological site such as vascular malformations described here. The structure, morphology and properties of the elastomeric matrices of this invention can be engineered or tailored over a wide range of performance by varying the starting materials and/or the processing conditions for different functional or therapeutic uses. [0085] The inventive implantable device is reticulated, i.e., comprises an interconnected network of pores and channels and voids that provides fluid permeability throughout the implantable device and permits cellular and tissue ingrowth and proliferation into the interior of the implantable device. The inventive implantable device is reticulated, i.e., comprises an interconnected and/or inter-communicating network of pores and channels and voids that provides fluid permeability throughout the implantable device and permits cellular and tissue ingrowth and proliferation into the interior of the implantable device. The inventive implantable device is reticulated, i.e., comprises an interconnected and/or inter-communicating network of pores and/or voids and/or channels that provides fluid permeability throughout the implantable device and permits cellular and tissue ingrowth and proliferation into the interior of the implantable device. The biodurable elastomeric matrix or material is considered to be reticulated because its microstructure or the interior structure comprises inter-connected and inter-communicating pores and/or voids bounded by configuration of the struts and intersections that constitute the solid structure. The continuous interconnected void phase is the principle feature of a reticulated structure. [0086] Preferred scaffold materials for the implants have a reticulated structure with sufficient and required liquid permeability and thus selected to permit blood, or other appropriate bodily fluid, and cells and tissues to access interior surfaces of the implants. This happens due to the presence of inter-connected and inter-communicating, reticulated open pores and/or voids and/or channels that form fluid passageways or fluid permeability providing fluid access all through. [0087] Preferred materials are at least partially hydrophobic reticulated, elastomeric polymeric matrix for fabricating implants according to the invention are flexible and resilient in recovery, so that the implants are also compressible materials enabling the implants to be compressed and, once the compressive force is released, to then recover to, or toward, substantially their original size and shape. For example, an implant can be compressed from a relaxed configuration or a size and shape to a compressed size and shape under ambient conditions, e.g., at 25° C. to fit into the introducer instrument for insertion into the vascular malformations (such as an aneurysm sac or endoloeak nexus within the sac). Alternatively, an implant may be supplied to the medical practitioner performing the implantation operation, in a compressed configuration, for example, contained in a package, preferably a sterile package. The resiliency of the elastomeric matrix that is used to fabricate the implant causes it to recover to a working size and configuration in situ, at the implantation site, after being released from its compressed state within the introducer instrument. The working size and shape or configuration can be substantially similar to original size and shape after the in situ recovery. [0088] Preferred scaffolds are reticulated elastomeric polymeric materials having sufficient structural integrity and durability to endure the intended biological environment, for the intended period of implantation. For structure and durability, at least partially hydrophobic polymeric scaffold materials are preferred although other materials may be employed if they meet the requirements described herein. Useful materials are preferably elastomeric in that they can be compressed and can resiliently recover to substantially the pre-compression state. Alternative reticulated polymeric materials with interconnected pores or networks of pores that permit biological fluids to have ready access throughout the interior of an implant may be employed, for example, woven or nonwoven fabrics or networked composites of microstructural elements of various forms. [0089] A partially hydrophobic scaffold is preferably constructed of a material selected to be sufficiently biodurable, for the intended period of implantation that the implant will not lose its structural integrity during the implantation time in a biological environment. The biodurable elastomeric matrices forming the scaffold do not exhibit significant symptoms of breakdown, degradation, erosion or significant deterioration of mechanical properties relevant to their use when exposed to biological environments and/or bodily stresses for periods of time commensurate with the use of the implantable device. In one embodiment, the desired period of exposure is to be understood to be at least 29 days, preferably several weeks and most preferably 2 to 5 years or more. This measure is intended to avoid scaffold materials that may decompose or degrade into fragments, for example, fragments that could have undesirable effects such as causing an unwanted tissue response. [0090] The void phase, preferably continuous and interconnected, of the reticulated polymeric matrix that is used to fabricate the implant of this invention may comprise as little as 50% by volume of the elastomeric matrix, referring to the volume provided by the interstitial spaces of elastomeric matrix before any optional interior pore surface coating or layering is applied. In one embodiment, the volume of void phase as just defined, is from about 70% to about 99% of the volume of elastomeric matrix. In another embodiment, the volume of void phase is from about 80% to about 98% of the volume of elastomeric matrix. In another embodiment, the volume of void phase is from about 90% to about 98% of the volume of elastomeric matrix. [0091] As used herein, when a pore is spherical or substantially spherical, its largest transverse dimension is equivalent to the diameter of the pore. When a pore is non-spherical, for example, ellipsoidal or tetrahedral, its largest transverse dimension is equivalent to the greatest distance within the pore from one pore surface to another, e.g., the major axis length for an ellipsoidal pore or the length of the longest side for a tetrahedral pore. For those skilled in the art, one can routinely estimate the pore frequency from the average cell diameter in microns. [0092] In one embodiment relating to vascular malformation applications and the like, to encourage cellular ingrowth and proliferation and to provide adequate fluid permeability, the average diameter or other largest transverse dimension of pores is at least about 50 μm. In another embodiment, the average diameter or other largest transverse dimension of pores is at least about 100 μm. In another embodiment, the average diameter or other largest transverse dimension of pores is at least about 150 μm. In another embodiment, the average diameter or other largest transverse dimension of pores is at least about 250 μm. In another embodiment, the average diameter or other largest transverse dimension of pores is greater than about 250 μm. In another embodiment, the average diameter or other largest transverse dimension of pores is greater than 250 μm. In another embodiment, the average diameter or other largest transverse dimension of pores is at least about 275 μm. In another embodiment, the average diameter or other largest transverse dimension of pores is greater than about 275 μm. In another embodiment, the average diameter or other largest transverse dimension of pores is greater than 275 μm. In another embodiment, the average diameter or other largest transverse dimension of pores is at least about 300 μm. In another embodiment, the average diameter or other largest transverse dimension of pores is greater than about 300 μm. In another embodiment, the average diameter or other largest transverse dimension of pores is greater than 300 μm. [0093] In another embodiment relating to vascular malformation applications and the like, the average diameter or other largest transverse dimension of pores is not greater than about 900 μm. In another embodiment, the average diameter or other largest transverse dimension of pores is not greater than about 850 μm. In another embodiment, the average diameter or other largest transverse dimension of pores is not greater than about 800 μm. In another embodiment, the average diameter or other largest transverse dimension of pores is not greater than about 700 μm. In another embodiment, the average diameter or other largest transverse dimension of pores is not greater than about 600 μm. In another embodiment, the average diameter or other largest transverse dimension of pores is not greater than about 500 μm. [0094] In one embodiment, the reticulated polymeric matrix that is used to fabricate the implants of this invention has any suitable bulk density, also known as specific gravity, consistent with its other properties. For example, in one embodiment, the bulk density may be from about 0.005 to about 0.15 g/cc (from about 0.31 to about 9.4 lb/ft 3 ), preferably from about 0.015 to about 0.115 g/cc (from about 0.93 to about 7.2 lb/ft 3 ) and most preferably from about 0.024 to about 0.104 g/cc (from about 1.5 to about 6.5 lb/ft 3 ). [0095] The reticulated elastomeric matrix has sufficient tensile strength such that it can withstand normal manual or mechanical handling during its intended application and during post-processing steps that may be required or desired without tearing, breaking, crumbling, fragmenting or otherwise disintegrating, shedding pieces or particles, or otherwise losing its structural integrity. The tensile strength of the starting material(s) should not be so high as to interfere with the fabrication or other processing of elastomeric matrix. Thus, for example, in one embodiment, the reticulated polymeric matrix that is used to fabricate the implants of this invention may have a tensile strength of from about 700 to about 52,500 kg/M 2 (from about 1 to about 75 psi). In another embodiment, elastomeric matrix may have a tensile strength of from about 7000 to about 28,000 kg/M 2 (from about 10 to about 40 psi). Sufficient ultimate tensile elongation is also desirable. For example, in another embodiment, reticulated elastomeric matrix has an ultimate tensile elongation of at least about 50% to at least about 500%. In yet another embodiment, reticulated elastomeric matrix has an ultimate tensile elongation of at least 75% to at least about 300%. [0096] One embodiment for use in the practice of the invention is a reticulated elastomeric implant which is sufficiently flexible and resilient, i.e., resiliently-compressible, to enable it to be initially compressed under ambient conditions, e.g., at 25° C., from a relaxed configuration to a first, compact configuration for delivery via a delivery-device, e.g., catheter, endoscope, syringe, cystoscope, trocar or other suitable introducer instrument, for delivery in vitro and, thereafter, to expand to a second, working configuration in situ. Furthermore, in another embodiment, an elastomeric matrix has the herein described resilient-compressibility after being compressed about 5-95% of an original dimension (e.g., compressed about 19/20th- 1/20th of an original dimension). In another embodiment, an elastomeric matrix has the herein described resilient-compressibility after being compressed about 10-90% of an original dimension (e.g., compressed about 9/10th- 1/10th of an original dimension). As used herein, elastomeric implant has “resilient-compressibility”, i.e., is “resiliently-compressible”, when the second, working configuration, in vitro, is at least about 50% of the size of the relaxed configuration in at least one dimension. In another embodiment, the resilient-compressibility of elastomeric implant is such that the second, working configuration, in vitro, is at least about 80% of the size of the relaxed configuration in at least one dimension. In another embodiment, the resilient-compressibility of elastomeric implant is such that the second, working configuration, in vitro, is at least about 90% of the size of the relaxed configuration in at least one dimension. In another embodiment, the resilient-compressibility of elastomeric implant is such that the second, working configuration, in vitro, is at least about 97% of the size of the relaxed configuration in at least one dimension. [0097] In another embodiment, an elastomeric matrix has the herein described resilient-compressibility after being compressed about 5-95% of its original volume (e.g., compressed about 19/20th- 1/20th of its original volume). In another embodiment, an elastomeric matrix has the herein described resilient-compressibility after being compressed about 10-90% of its original volume (e.g., compressed about 9/10th- 1/10th of its original volume). As used herein, “volume” is the volume swept-out by the outermost three-dimensional contour of the elastomeric matrix. In another embodiment, the resilient-compressibility of elastomeric implant is such that the second, working configuration, in vivo, is at least about 50% of the volume occupied by the relaxed configuration. In another embodiment, the resilient-compressibility of elastomeric implant is such that the second, working configuration, in vivo, is at least about 80% of the volume occupied by the relaxed configuration. In another embodiment, the resilient-compressibility of elastomeric implant is such that the second, working configuration, in vivo, is at least about 90% of the volume occupied by the relaxed configuration. In another embodiment, the resilient-compressibility of elastomeric implant is such that the second, working configuration, in vivo, occupies at least about 97% of the of volume occupied by the elastomeric matrix in its relaxed configuration. [0098] Without being bound by any particular theory, it is believed that the absence or substantial absence of cell walls in reticulated implants when compressed to very high degree will allow them to demonstrate resilient recovery in shorter time (such as recovery time of under 15 seconds when compressed to 75% of their relaxed configuration for 10 minutes and recovery time of under 35 seconds when compressed to 90% of their relaxed configuration for 10 minutes) as compared to un-reticulated porous foams. [0099] In one embodiment, reticulated elastomeric matrix that is used to fabricate the implants of this invention has a compressive strength of from about 700 to about 70,000 kg/m 2 (from about 1 to about 100 psi) at 50% compression strain. In another embodiment, reticulated elastomeric matrix has a compressive strength of from about 1,400 to about 105,000 kg/m (from about 2 to about 150 psi) at 75% compression strain. [0100] In another embodiment, reticulated elastomeric matrix that is used to fabricate the implants of this invention has a compression set, when compressed to 50% of its thickness at about 25° C., of not more than about 30%. In another embodiment, elastomeric matrix has a compression set of not more than about 20%. In another embodiment, elastomeric matrix has a compression set of not more than about 10%. In another embodiment, elastomeric matrix has a compression set of not more than about 5%. [0101] In another embodiment, reticulated elastomeric matrix that is used to fabricate the implants of this invention has a tear strength, of from about 0.18 to about 1.78 kg/linear cm (from about 1 to about 10 lbs/linear inch). [0102] In another embodiment of the invention the reticulated elastomeric matrix that is used to fabricate the implant can be readily permeable to liquids, permitting flow of liquids, including blood, through the composite device of the invention. The water permeability of the reticulated elastomeric matrix is from about 50 l/min./psi/cm 2 to about 500 l/min./psi/cm 2 , preferably from about 100 l/min./psi/cm 2 to about 300 l/min./psi/cm 2 . In contrast, permeability of the unreticulated elastomeric matrix is below about 1 l/min./psi/cm 2 . In another embodiment, the permeability of the unretriculated elastomeric amtrix is below about 5 l/min./psi/cm 2 . [0103] In general, suitable biodurable reticulated elastomeric partially hydrophobic polymeric matrix that is used to fabricate the implant of this invention or for use as scaffold material for the implant in the practice of the present invention, in one embodiment sufficiently well characterized, comprise elastomers that have or can be formulated with the desirable mechanical properties described in the present specification and have a chemistry favorable to biodurability such that they provide a reasonable expectation of adequate biodurability. [0104] Various biodurable reticulated hydrophobic polyurethane materials are suitable for this purpose. In one embodiment, structural materials for the inventive reticulated elastomers are synthetic polymers, especially, but not exclusively, elastomeric polymers that are resistant to biological degradation, for example, polycarbonate polyurethane-urea, polycarbonate polyurea-urethane, polycarbonate polyurethane, polycarbonate polysiloxane polyurethane, and polysiloxane polyurethane, and the like. Such elastomers are generally hydrophobic but, pursuant to the invention, may be treated to have surfaces that are less hydrophobic or somewhat hydrophilic. In another embodiment, such elastomers may be produced with surfaces that are less hydrophobic or somewhat hydrophilic. [0105] The invention can employ, for implanting, a biodurable reticulatable elastomeric partially hydrophobic polymeric scaffold material or matrix for fabricating the implant or a material. More particularly, in one embodiment, the invention provides a biodurable elastomeric polyurethane scaffold material or matrix which is made by synthesizing the scaffold material or matrix preferably from a polycarbonate polyol component and an isocyanate component by polymerization, cross-linking and foaming, thereby forming pores, followed by reticulation of the porous material to provide a biodurable reticulated elastomeric product with inter-connected and/or inter-communicating pores and channels. The product is designated as a polycarbonate polyurethane, being a polymer comprising urethane groups formed from, e.g., the hydroxyl groups of the polycarbonate polyol component and the isocyanate groups of the isocyanate component. In another embodiment, the invention provides a biodurable elastomeric polyurethane scaffold material or matrix which is made by synthesizing the scaffold material or matrix preferably from a polycarbonate polyol component and an isocyanate component by polymerization, cross-linking and foaming, thereby forming pores, and using water as a blowing agent and/or foaming agent during the synthesis, followed by reticulation of the porous material to provide a biodurable reticulated elastomeric product with inter-connected and/or inter-communicating pores and channels. This product is designated as a polycarbonate polyurethane-urea or polycarbonate polyurea-urethane, being a polymer comprising urethane groups formed from, e.g., the hydroxyl groups of the polycarbonate polyol component and the isocyanate groups of the isocyanate component and also comprising urea groups formed from reaction of water with the isocyanate groups. In all of these embodiments, the process employs controlled chemistry to provide a reticulated elastomeric matrix or product with good biodurability characteristics. The matrix or product employing chemistry that avoids biologically undesirable or nocuous constituents therein. [0106] In one embodiment, the starting material for synthesizing the biodurable reticulated elastomeric partially hydrophobic polymeric matrix contains at least one polyol component to provide the so-called soft segement. For the purposes of this application, the term “polyol component” includes molecules comprising, on the average, about 2 hydroxyl groups per molecule, i.e., a difunctional polyol or a diol, as well as those molecules comprising, on the average, greater than about 2 hydroxyl groups per molecule, i.e., a polyol or a multi-functional polyol. In one embodiment, this soft segment polyol is terminated with hydroxyl groups, either primary or secondary. Exemplary polyols can comprise, on the average, from about 2 to about 5 hydroxyl groups per molecule. In one embodiment, as one starting material, the process employs a difunctional polyol component in which the hydroxyl group functionality of the diol is about 2. In another embodiment, the soft segment is composed of a polyol component that is generally of a relatively low molecular weight, typically from about 500 to about 6,000 daltons and preferably between 1000 to 2500 daltons. Examples of suitable polyol components include but not limited to polycarbonate polyol, hydrocarbon polyol, polysiloxane polyol, poly(carbonate-co-hydrocarbon)polyol, poly(carbonate-co-siloxane)polyol, poly(hydrocarbon-co-siloxane)polyol, polysiloxane polyol and copolymers and mixtures thereof. [0107] In one embodiment, the starting material for synthesizing the biodurable reticulated elastomeric partially hydrophobic polymeric matrix contains at least one isocyanate component and, optionally, at least one chain extender component to provide the so-called “hard segment”. In one embodiment, the starting material for synthesizing the biodurable reticulated elastomeric partially hydrophobic polymeric matrix contains at least one isocyanate component. For the purposes of this application, the term “isocyanate component” includes molecules comprising, on the average, about 2 isocyanate groups per molecule as well as those molecules comprising, on the average, greater than about 2 isocyanate groups per molecule. The isocyanate groups of the isocyanate component are reactive with reactive hydrogen groups of the other ingredients, e.g., with hydrogen bonded to oxygen in hydroxyl groups and with hydrogen bonded to nitrogen in amine groups of the polyol component, chain extender, crosslinker and/or water. In one embodiment, the average number of isocyanate groups per molecule in the isocyanate component is about 2. In another embodiment, the average number of isocyanate groups per molecule in the isocyanate component is greater than about 2 is greater than 2. [0108] In one embodiment, a small quantity of an optional ingredient, such as a multi-functional hydroxyl compound or other cross-linker having a functionality greater than 2, is present to allow crosslinking and/or to achieve a stable foam, i.e., a foam that does not collapse to become non-foamlike. Alternatively, or in addition, polyfunctional adducts of aliphatic and cycloaliphatic isocyanates can be used to impart cross-linking in combination with aromatic diisocyanates. Alternatively, or in addition, polyfunctional adducts of aliphatic and cycloaliphatic isocyanates can be used to impart cross-linking in combination with aliphatic diisocyanates. The presence of these components and adducts with functionality higher than 2 in the hard segment component allows for cross-linking to occur. [0109] Exemplary diisocyanates include aliphatic diisocyanates, isocyanates comprising aromatic groups, the so-called “aromatic diisocyanates”, and mixtures thereof. Aliphatic diisocyanates include tetramethylene diisocyanate, cyclohexane-1,2-diisocyanate, cyclohexane-1,4-diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, methylene-bis-(p-cyclohexyl isocyanate) (“H12 MDI”), and mixtures thereof. Aromatic diisocyanates include p-phenylene diisocyanate, 4,4′-diphenylmethane diisocyanate (“4,4′-MDI”), 2,4′-diphenylmethane diisocyanate (“2,4′-MDI”), polymeric MDI, and mixtures thereof. Examples of optional chain extenders include diols, diamines, alkanol amines or a mixture thereof. [0110] In one embodiment, the starting material for synthesizing the biodurable reticulated elastomeric partially hydrophobic polymeric matrix contains at least one blowing agent such as water. Other exemplary blowing agents include the physical blowing agents, e.g., volatile organic chemicals such as hydrocarbons, ethanol and acetone, and various fluorocarbons, hydrofluorocarbons, chlorofluorocarbons, and hydrochlorofluorocarbons. In one embodiment, the hard segments also contain a urea component formed during foaming reaction with water. In one embodiment, the reaction of water with an isocyanate group yields carbon dioxide, which serves as a blowing agent. The amount of blowing agent, e.g., water, is adjusted to obtain different densities of non-reticulated foams. A reduced amount of blowing agent such as water may reduce the number of urea linkages in the material. [0111] In one embodiment, implantable device can be rendered radiopaque to facilitate in vivo imaging, for example, by adhering to, covalently bonding to and/or incorporating into the elastomeric matrix itself particles of a radio-opaque material. Radio-opaque materials include titanium, tantalum, tungsten, barium sulfate or other suitable material known to those skilled in the art. [0112] In one embodiment, the starting material of the biodurable reticulated elastomeric partially hydrophobic polymeric matrix is a commercial polyurethane polymers are linear, not crosslinked, polymers, therefore, they are soluble, can be melted, readily analyzable and readily characterizable. In this embodiment, the starting polymer provides good biodurability characteristics. The reticulated elastomeric matrix is produced by taking a solution of the commercial polymer such as polyurethane and charging it into a mold that has been fabricated with surfaces defining a microstructural configuration for the final implant or scaffold, solidifying the polymeric material and removing the sacrificial mold by melting, dissolving or subliming-away the sacrificial mold. The matrix or product employing a foaming process that avoids biologically undesirable or nocuous constituents therein. [0113] Of particular interest are thermoplastic elastomers such as polyurethanes whose chemistry is associated with good biodurability properties, for example. In one embodiment, such thermoplastic polyurethane elastomers include polycarbonate polyurethanes, polysiloxane polyurethanes, polyurethanes with so-called “mixed” soft segments, and mixtures thereof. Mixed soft segment polyurethanes are known to those skilled in the art and include, e.g., polycarbonate-polysiloxane polyurethanes. In another embodiment, the thermoplastic polyurethane elastomer comprises at least one diisocyanate in the isocyanate component, at least one chain extender and at least one diol, and may be formed from any combination of the diisocyanates, difunctional chain extenders and diols described in detail above. Some suitable thermoplastic polyurethanes for practicing the invention, in one embodiment suitably characterized as described herein, include: polyurethanes with mixed soft segments comprising polysiloxane together with a polycarbonate component. [0114] In one embodiment, the weight average molecular weight of the thermoplastic elastomer is from about 30,000 to about 500,000 Daltons. In another embodiment, the weight average molecular weight of the thermoplastic elastomer is from about 50,000 to about 250,000 Daltons. [0115] Some commercially-available thermoplastic elastomers suitable for use in practicing the present invention include the line of polycarbonate polyurethanes supplied under the trademark BIONATE® by The Polymer Technology Group Inc. (Berkeley, Calif.). For example, the very well-characterized grades of polycarbonate polyurethane polymer BIONATE® 80A, 55 and 90 are soluble in THF, DMF, DMAT, DMSO, or a mixture of two or more thereof, processable, reportedly have good mechanical properties, lack cytotoxicity, lack mutagenicity, lack carcinogenicity and are non-hemolytic. Another commercially-available elastomer suitable for use in practicing the present invention is the CHRONOFLEX® C line of biodurable medical grade polycarbonate aromatic polyurethane thermoplastic elastomers available from CardioTech International, Inc. (Woburn, Mass.). [0116] Other possible embodiments of the materials used to fabricate the implants of this invention are described in co-pending, commonly assigned U.S. patent applications Ser. No. 10/749,742, filed Dec. 30, 2003, titled “Reticulated Elastomeric Matrices, Their Manufacture and Use in Implantable Devices”, Ser. No. 10/848,624, filed May 17, 2004, titled “Reticulated Elastomeric Matrices, Their Manufacture and Use In Implantable Devices”, and Ser. No. 10/990,982, filed Jul. 27, 2004, titled “Endovascular Treatment Devices and Methods”, each of which is incorporated herein by reference in its entirely. [0117] If desired, the reticulated elastomeric implants or implants for packing the aneurysm sac or for other vascular occlusion can be rendered radiopaque to allow for visualization of the implants in situ by the clinician during and after the procedure, employing radioimaging. Any suitable radiopaque agent that can be covalently bound, adhered or otherwise attached to the reticulated polymeric implants may be employed including without limitation, tantalum and barium sulfate. In addition to incorporating radiopaque agents such as tantalum into the implant material itself, a further embodiment of the invention encompasses the use of radiopaque metallic components to impart radiopacity to the implant. For example, thin filaments comprised of metals with shape memory properties such as platinum or nitinol can be embedded into the implant and may be in the form of a straight or curved wire, helical or coil-like structure, umbrella structure, or other structure generally known to those skilled in the art. Alternatively, a metallic frame around the implant may also be used to impart radiopacity. The metallic frame may be in the form of a tubular structure similar to a stent, a helical or coil-like structure, an umbrella structure, or other structure generally known to those skilled in the art. Attachment of radiopaque metallic components to the implant can be accomplished by means including but not limited to chemical bonding or adhesion, suturing, pressure fitting, compression fitting, and other physical methods. [0118] Some optional embodiments of the invention comprise apparatus or devices and treatment methods employing biodurable reticulated elastomeric implants 36 into which biologically active agents are incorporated for the matrix to be used for controlled release of pharmaceutically-active agents, such as a drug, and for other medical applications. Any suitable agents may be employed as will be apparent to those skilled in the art, including, for example, but without limitation thrombogenic agents, e.g., thrombin, anti-inflammatory agents, and other therapeutic agents that may be used for the treatment of abdominal aortic aneurysms. The invention includes embodiments wherein the reticulated elastomeric material of the implants is employed as a drug delivery platform for localized administration of biologically active agents into the aneurysm sac. Such materials may optionally be secured to the interior surfaces of elastomeric matrix directly or through a coating. In one embodiment of the invention the controllable characteristics of the implants are selected to promote a constant rate of drug release during the intended period of implantation. [0119] The implants with reticulated structure with sufficient and required liquid permeability and permit blood, or other appropriate bodily fluid, to access interior surfaces of the implants, which optionally are drug-bearing. This happens due to the presence of inter-connected, reticulated open pores that form fluid passageways or fluid permeability providing fluid access all through and to the interior of the matrix for elution of pharmaceutically-active agents, e.g., a drug, or other biologically useful materials. [0120] In a further embodiment of the invention, the pores of biodurable reticulated elastomeric matrix that are used to fabricate the implants of this invention are coated or filled with a cellular ingrowth promoter. In another embodiment, the promoter can be foamed. In another embodiment, the promoter can be present as a film. The promoter can be a biodegradable material to promote cellular invasion of pores biodurable reticulated elastomeric matrix that are used to fabricate the implants of this invention in vivo. Promoters include naturally occurring materials that can be enzymatically degraded in the human body or are hydrolytically unstable in the human body, such as fibrin, fibrinogen, collagen, elastin, hyaluronic acid and absorbable biocompatible polysaccharides, such as chitosan, starch, fatty acids (and esters thereof), glucoso-glycans and hyaluronic acid. In some embodiments, the pore surface of the biodurable reticulated elastomeric matrix that are used to fabricate the implants of this invention is coated or impregnated, as described in the previous section but substituting the promoter for the biocompatible polymer or adding the promoter to the biocompatible polymer, to encourage cellular ingrowth and proliferation. [0121] One possible material for use in the present invention comprises a resiliently compressible composite polyurethane material comprising a hydrophilic foam coated on and throughout the pore surfaces of a hydrophobic foam scaffold. One suitable such material is the composite foam disclosed in co-pending, commonly assigned U.S. patent applications Ser. No. 10/692,055, filed Oct. 22, 2003, Ser. No. 10/749,742, filed Dec. 30, 2003, Ser. No. 10/848,624, filed May 17, 2004, and Ser. No. 10/900,982, filed Jul. 27, 2004, each of which is incorporated herein by reference in its entirety. The hydrophobic foam provides support and resilient compressibility enabling the desired collapsing of the implant for delivery and reconstitution in situ. [0122] The reticulated biodurable elastomeric and at least partially hydrophilic material can be used to carry a variety of therapeutically useful agents, for example, agents that can aid in the healing of the aneurysm, such as elastin, collagen or other growth factors that will foster fibroblast proliferation and ingrowth into the aneurysm, agents to render the foam implant non-thrombogenic, or inflammatory chemicals to foster scarring of the aneurysm. Furthermore the hydrophilic foam, or other agent immobilizing means, can be used to carry genetic therapies, e.g. for replacement of missing enzymes, to treat atherosclerotic plaques at a local level, and to release agents such as antioxidants to help combat known risk factors of aneurysm. [0123] Pursuant to the present invention it is contemplated that the pore surfaces may employ other means besides a hydrophilic foam to secure desired treatment agents to the hydrophobic foam scaffold. [0124] The agents contained within the implant can provide an inflammatory response within the aneurysm, causing the walls of the aneurysm to scar and thicken. This can be accomplished using any suitable inflammation inducing chemicals, such as sclerosants like sodium tetradecyl sulphate (STS), polyiodinated iodine, hypertonic saline or other hypertonic salt solution. Additionally, the implant can contain factors that will induce fibroblast proliferation, such as growth factors, tumor necrosis factor and cytokines. EXAMPLES Example 1 Fabrication of a Crosslinked Reticulated Polyurethane Matrix [0125] The aromatic isocyanate RUBINATE 9258 (from Huntsman) was used as the isocyanate component. RUBINATE 9258, which is a liquid at 25° C., contains 4,4′-MDI and 2,4′-MDI and has an isocyanate functionality of about 2.33. A diol, poly(1,6-hexanecarbonate)diol (POLY-CD CD220 from Arch Chemicals) with a molecular weight of about 2,000 Daltons was used as the polyol component and was a solid at 25° C. Distilled water was used as the blowing agent. The blowing catalyst used was the tertiary amine triethylenediamine (33% in dipropylene glycol; DABCO 33LV from Air Products). A silicone-based surfactant was used (TEGOSTAB(® BF 2370 from Goldschmidt). A cell-opener was used (ORTEGOL® 501 from Goldschmidt). The viscosity modifier propylene carbonate (from Sigma-Aldrich) was present to reduce the viscosity. The proportions of the components that were used are set forth in the following table: TABLE 1 Ingredient Parts by Weight Polyol Component 100 Viscosity Modifier 5.80 Surfactant 0.66 Cell Opener 1.00 Isocyanate Component 47.25 Isocyanate Index 1.00 Distilled Water 2.38 Blowing Catalyst 0.53 [0126] The polyol component was liquefied at 70° C. in a circulating-air oven, and 100 g thereof was weighed out into a polyethylene cup. 5.8 g of viscosity modifier was added to the polyol component to reduce the viscosity, and the ingredients were mixed at 3100 rpm for 15 seconds with the mixing shaft of a drill mixer to form “Mix-1”. 0.66 g of surfactant was added to Mix-1, and the ingredients were mixed as described above for 15 seconds to form “Mix-2”. Thereafter, 1.00 g of cell opener was added to Mix-2, and the ingredients were mixed as described above for 15 seconds to form “Mix-3”. 47.25 g of isocyanate component were added to Mix-3, and the ingredients were mixed for 60±10 seconds to form “System A”. [0127] 2.38 g of distilled water was mixed with 0.53 g of blowing catalyst in a small plastic cup for 60 seconds with a glass rod to form “System B”. [0128] System B was poured into System A as quickly as possible while avoiding spillage. The ingredients were mixed vigorously with the drill mixer as described above for 10 seconds and then poured into a 22.9 cm×20.3 cm×12.7 cm (9 in.×8 in.×5 in.) cardboard box with its inside surfaces covered by aluminum foil. The foaming profile was as follows: 10 seconds mixing time, 17 seconds cream time, and 85 seconds rise time. [0129] Two minutes after the beginning of foaming, i.e., the time when Systems A and B were combined, the foam was placed into a circulating-air oven maintained at 100-105° C. for curing for from about 55 to about 60 minutes. Then, the foam was removed from the oven and cooled for 15 minutes at about 25° C. The skin was removed from each side using a band saw. Thereafter, hand pressure was applied to each side of the foam to open the cell windows. The foam was replaced into the circulating-air oven and postcured at 100-105° C. for an additional four hours. [0130] The average pore diameter of the foam, as determined from optical microscopy observations, was greater than about 275 μm. [0131] The following foam testing was carried out according to ASTM D3574: Bulk density was measured using specimens of dimensions 50 mm×50 mm×25 mm. The density was calculated by dividing the weight of the sample by the volume of the specimen. A density value of 2.81 lbs/ft 3 (0.0450 g/cc) was obtained. [0132] Tensile tests were conducted on samples that were cut either parallel to or perpendicular to the direction of foam rise. The dog-bone shaped tensile specimens were cut from blocks of foam. Each test specimen measured about 12.5 mm thick, about 25.4 mm wide, and about 140 mm long; the gage length of each specimen was 35 mm and the gage width of each specimen was 6.5 mm. Tensile properties (tensile strength and elongation at break) were measured using an INSTRON Universal Testing Instrument Model 1122 with a cross-head speed of 500 mm/min (19.6 inches/minute). The average tensile strength perpendicular to the direction of foam rise was determined as 29.3 psi (20,630 kg/m 2 ). The elongation to break perpendicular to the direction of foam rise was determined to be 266%. [0133] The measurement of the liquid flow through the material is measured in the following way using a iquid permeability apparatus or Liquid Permeaeter (Porous Materials, Inc., Ithaca, N.Y.). The foam sample was 8.5 mm in thickness and covered a hole 6.6 mm in diameter in the center of a metal plate that was placed at the bottom of the Liquid Permeaeter filled with water. Thereafter, the air pressure above the sample was increased slowly to extrude the liquid from the sample and the permeability of water through the foam was determined to be 0.11 L/min/psi/cm 2. EXAMPLE 2 Reticulation of a Crosslinked Polyurethane Foam [0134] Reticulation of the foam described in Example 1 was carried out by the following procedure: A block of foam measuring approximately 15.25 cm×15.25 cm×7.6 cm (6 in.×6 in.×3 in.) was placed into a pressure chamber, the doors of the chamber were closed, and an airtight seal to the surrounding atmosphere was maintained. The pressure within the chamber was reduced to below about 100 millitorr by evacuation for at least about two minutes to remove substantially all of the air in the foam. A mixture of hydrogen and oxygen gas, present at a ratio sufficient to support combustion, was charged into the chamber over a period of at least about three minutes. The gas in the chamber was then ignited by a spark plug. The ignition exploded the gas mixture within the foam. The explosion was believed to have at least partially removed many of the cell walls between adjoining pores, thereby forming a reticulated elastomeric matrix structure. [0135] The average pore diameter of the reticulated elastomeric matrix, as determined from optical microscopy observations, was greater than about 275 μm. A scanning electron micrograph image of the reticulated elastomeric matrix of this example (not shown here) demonstrated, e.g., the communication and interconnectivity of pores therein. [0136] The density of the reticulated foam was determined as described above in Example 1. A post-reticulation density value of 2.83 lbs/ft 3 (0.0453 g/cc) was obtained. [0137] Tensile tests were conducted on reticulated foam samples as described above in Example 1. The average post-reticulation tensile strength perpendicular to the direction of foam rise was determined as about 26.4 psi (18,560 kg/m 2 ). The post-reticulation elongation to break perpendicular to the direction of foam rise was determined to be about 250%. The average post-reticulation tensile strength parallel to the direction of foam rise was determined as about 43.3 psi (30,470 kg/m 2 ). The post-reticulation elongation to break parallel to the direction of foam rise was determined to be about 270%. [0138] Compressive tests were conducted using specimens measuring 50 mm×50 mm×25 mm. The tests were conducted using an INSTRON Universal Testing Instrument Model 1122 with a cross-head speed of 10 mm/min (0.4 inches/minute). The post-reticulation compressive strengths at 50% compression, parallel to and perpendicular to the direction of foam rise, were determined to be 1.53 psi (1,080 kg/m 2 ) and 0.95 psi (669 kg/m 2 ), respectively. The post-reticulation compressive strengths at 75% compression, parallel to and perpendicular to the direction of foam rise, were determined to be 3.53 psi (2,485 kg/m 2 ) and 2.02 psi (1,420 kg/m 2 ), respectively. The post-reticulation compression set, determined after subjecting the reticulated sample to 50% compression for 22 hours at 25° C. then releasing the compressive stress, parallel to the direction of foam rise, was determined to be about 4.5%. [0139] The resilient recovery of the reticulated foam was measured by subjecting 1 inch (25.4 mm) diameter and 0.75 inch (19 mm) long foam cylinders to 75% uniaxial compression in their length direction for 10 or 30 minutes and measuring the time required for recovery to 90% (“t-90%”) and 95% (“t-95%”) of their initial length. The percentage recovery of the initial length after 10 minutes (“r-10”) was also determined. Separate samples were cut and tested with their length direction parallel to and perpendicular to the foam rise direction. The results obtained from an average of two tests are shown in the following table: TABLE 2 Time compressed Test Sample t-90% t-95% r-10 (min) Orientation (sec) (sec) (%) 10 Parallel 6 11 100 10 Perpendicular 6 23 100 30 Parallel 9 36 99 30 Perpendicular 11 52 99 [0140] In contrast, a comparable foam with little to no reticulation typically has t-90 values of greater than about 60-90 seconds after 10 minutes of compression. [0141] The measurement of the liquid flow through the material is measured in the following way using a Liquid permeability apparatus or Liquid Permeaeter (Porous Materials, Inc., Ithaca, N.Y.). The foam samples were between 7.0 and 7.7 mm in thickness and covered a hole 8.2 mm in diameter in the center of a metal plate that was placed at the bottom of the Liquid Permeaeter filled with water. The water was allowed to extrude through the sample under gravity and the permeability of water through the foam was determined to be 180 L/min/psi/cm 2 in the direction of foam rise and 160 L/min/psi/cm 2 in the perpendicular to foam rise. EXAMPLE 3 Implantation of a Plurality of Crosslinked Reticulated Polyurethane Matrix Implants into a Canine Carotid Bifurcation Aneurysm Model [0142] An established animal model of cerebral aneurysms was used to evaluate the angiographic and histologic outcomes of implanting a plurality of implants machined from a block of cross-linked reticulated polyurethane matrix as described in Example 2. Differing packing densities were utilized to evaluate the effects on angiographic occlusion at 2-week and 1-month timepoints. The one-month animal was sacrificed to assess tissue response to the cross-linked reticulated polyurethane matrix. [0143] An aneurysm was surgically created at the carotid arterial bifurcation of three dogs. This model simulates the hemodynamics of a human saccular aneurysm, which typically occurs at an arterial bifurcation. After one month, a second embolization procedure was performed in which a plurality of implants machined from a block of cross-linked reticulated polyurethane matrix was delivered into the aneurysm sac using a guide catheter. One of two different implant configurations was used in this experiment. The first configuration was a cylindrical implant measuring 6 mm diameter×15 mm length, delivered using a commercially available 7 Fr Cordis Vista-Brite guide catheter. The second configuration was a segmented, cylindrical implant measuring 3 mm diameter×15 mm length, delivered using a commercially available 5 Fr Cordis Vista-Brite guide catheter. A loader apparatus was used to compress the implants from their expanded state into a compressed state for introduction through the hemostasis valve of the guide catheter. An obturator was then used to push the compressed implant from the proximal end of the guide catheter to the distal end, where the implant was deployed in a slow, controlled manner into the aneurysm sac. [0144] A sufficient number of implants was used in each of the three dogs to achieve post-procedural angiographic occlusion. Platinum coil markers embedded in the central lumen of the implants allowed the implants to be readily visualized under standard fluoroscopy, to verify implant deployment, placement, and positioning. [0145] Post-procedural angiographic occlusion was achieved in all three animals. At either two weeks or one month following the embolization procedure, a follow-up angiogram was performed to assess angiographic outcomes at follow-up. Stable and/or progression angiographic occlusion was noted in all three dogs with no evidence of recanalization. In addition, analysis of implant positioning at follow-up indicated that the implants remained stable without any migration or compaction. The results are summarized in the table below: TABLE 3 Aneurysm Aneurysm 6 × 15 mm 3 × 15 mm Packing Angiographic Outcomes at Dog # Dimensions (mm) Volume (mm 3 ) Implants (n) Implants (n) Density (%) Followup vs. Baseline 001 22.4 mm L × 10.1 mm W 1884 mm 3 2 5  73% Progressing Occlusion At 2-Week Followup 002 18.9 mm L × 8.8 mm W 1207 mm 3 4 9 204% Stable Occlusion At 2- Week Followup 003 23 mm L × 11 mm W 2295 mm 3 12 0 222% 100% Occlusion at 1- Month Followup [0146] The one-month animal was sacrificed to assess tissue response to the cross-linked reticulated polyurethane matrix. Gross observation indicated that the aneurysm sac was fully packed with no open spaces. Histology analysis showed a mild inflammatory response with a high degree of tissue ingrowth. Infiltration by inflammatory cells and migrating fibroblasts was consistent with aneurysm healing. There was no evidence of unorganized blood clotting which is thought to lead to aneurysm recanalization. This experiment supported the efficacy of crosslinked reticulated polyurethane implants for the treatment of cerebral aneurysms. [0147] One possible material for use in the present invention comprises a resiliently compressible composite polyurethane foam comprising a hydrophilic foam coated on and throughout the pore surfaces of a hydrophobic foam scaffold. One suitable such material is the composite foam disclosed in co-pending, commonly assigned U.S. patent applications Ser. No. 10/692,055, filed Oct. 22, 2003, Ser. No. 10/749,742, filed Dec. 30, 2003, Ser. No. 10/848,624, filed May 17, 2004, and Ser. No. 10/900,982, filed Jul. 27, 2004, each of which is incorporated herein by reference in its entirety. The hydrophobic foam provides support and resilient compressibility enabling the desired collapsing of the implant for delivery and reconstitution in situ. [0148] The hydrophilic foam can be used to carry a variety of therapeutically useful agents, for example, agents that can aid in the healing of the aneurysm, such as elastin, collagen or other growth factors that will foster fibroblast proliferation and ingrowth into the aneurysm, agents to render the foam implant non-thrombogenic, or inflammatory chemicals to foster scarring of the aneurysm. Furthermore the hydrophilic foam, or other agent immobilizing means, can be used to carry genetic therapies, e.g. for replacement of missing enzymes, to treat atherosclerotic plaques at a local level, and to release agents such as antioxidants to help combat known risk factors of aneurysm. [0149] Pursuant to the present invention it is contemplated that the pore surfaces may employ other means besides a hydrophilic foam to secure desired treatment agents to the hydrophobic foam scaffold. [0150] The agents contained within the implant can provide an inflammatory response within the aneurysm, causing the walls of the aneurysm to scar and thicken. This can be accomplished using any suitable inflammation inducing chemicals, such as sclerosants like sodium tetradecyl sulphate (STS), polyiodinated iodine, hypertonic saline or other hypertonic salt solution. Additionally, the implant can contain factors that will induce fibroblast proliferation, such as growth factors, tumor necrosis factor and cytokines. [0151] In one embodiment the reticulated biodurable elastomeric matrix can have a larger dimension of from about 1 to about 100 mm optionally from about 3 to 50 mm, when a plurality of relatively small implants is employed. [0152] While illustrative embodiments of the invention have been described, it is, of course, understood that various modifications of the invention will be obvious to those of ordinary skill in the art. Such modifications are within the spirit and scope of the invention which is limited and defined only by the appended claims.

An aneurysm treatment device for in situ treatment of aneurysms comprises a collapsible member having a first shape wherein the first shape is an expanded geometric configuration, and a second shape, wherein the second shape is a collapsed configuration that is loadable into a catheter. The aneurysm treatment device is capable of returning to the first shape in the sac of an aneurysm upon deployment, where it occludes the aneurysm.

FIELD OF USE This invention relates to teeming molten metal (for example, liquid steel) from a movable ladle having a slide gate nozzle into a plurality of ingot molds. More specifically, the invention relates to protecting the molten metal from the well-known, harmful effects of normal atmosphere absorption by surrounding the molten metal with an envelope of inert gas. Thus, in the case of molten steel, oxygen and nitrogen cannot be readily absorbed by the steel. DESCRIPTION OF THE PRIOR ART The advantage of protecting molten metal from the atmosphere during teeming is well understood. Numerous shrouding devices and methods have been proposed. A great number are directed to continuous casting apparatus wherein the ladle and the mold remain stationary at all times. Typical United States patents relating to such apparatus are the following: U.S. Pat. Nos. 3,102,591; 3,265,348; 3,402,757; 3,439,735; 3,451,594; 3,572,422; 3,756,305; 3,841,385; 3,908,734; 3,963,224; 4,084,799; 4,090,552; 4,102,386; 4,200,138; and 4,218,048. Keel et al. U.S. Pat. No. 3,174,200 is pertinent for showing a process and apparatus for purging a mold with an inert gas. It teaches providing a vented cover for the mold which will melt away upon commencement of teeming and providing a narrow shroud casing (narrower than the opening in the mold) of a fixed length hung from the lower surface of the ladle. The ladle, due to the fixed length of the casing, must be raised and lowered to accommodate molds of varying height. The Keel et al. patent teaches an argon flow rate of between 16 and 20 cubic feet per minute. Poole et al. U.S. Pat. No. 4,211,390 relates to an apparatus for protecting a stream of molten metal during teeming with an inert gas. The stream is surrounded by a collapsible shield comprised of two coaxial cylinders. Each cylinder is supported for vertical movement from bifurcated arms fixed relative to the ladle carriage which arms permit adjustment of the length of the shield thus providing a certain amount of accommodation for ingot molds for diverse heights. However, the shield is not adapted for use with slide gate nozzles nor to be turned about two axes to accommodate molds having an uneven top edge. Hind et al. U.S. Pat. No. 4,131,219 relates to pouring molten metal from a ladle having a slide gate on the bottom thereof. Inert gas is forced through nozzles in the direction of the flowing metal stream for the purpose of forming an annular curtain of gas. The pressures upstream of the nozzles are in the vicinity of 10 to 20 psi and the flow rates are between 30 and 40 cubic feet per minute. No mechanical shield is disclosed or even suggested by Hind et al. It is an advantage according to this invention to provide a method and apparatus for teeming molten metal from a ladle having a slide gate. The molten metal stream is protected by inert gas at a static pressure just exceeding atmospheric pressure. The apparatus according to this invention provides a gas shroud for the stream without any time penalty for lifting and lowering the ladle and accommodates the slide gate motion without ladle manipulation. It is an advantage of this invention that teeming aluminum killed steel from a ladle having a slide gate into traditional ingot molds can be slowed without excessive nozzle clogging. This slow teeming has several benefits, including reduction of surface cracks in the ingot which cause semifinish rejects. SUMMARY OF THE INVENTION Briefly according to this invention, there is provided an apparatus for providing a protective gas shroud around molten metal being teemed from a ladle having a slide gate secured to the bottom thereof. The apparatus comprises a plenum box sealed to and extending downwardly from the sliding part of the slide gate. It further comprises a hood arranged to telescope over the plenum box forming a rough sliding seal therewith. The hood has a skirt flange at the bottom thereof. The width of the skirt flange in the direction of movement of the slide gate is preferably greater than the maximum slide gate movement. An actuating mechanism fixed relative to the plenum box raises and lowers the hood. Conduits are provided for introducing a protective gas into the plenum box. Thus the ladle may be aligned with the mold into which hot metal is to be teemed. The actuating mechanism then lowers the hood so that the skirt flange rests upon the top of the mold or hot top. Thereafter the slide gate may be opened dragging the hood over the top of the mold into alignment therewith. More specifically, this invention is related to an apparatus secured to the bottom of a slide gate assembly typically comprising a fixed apertured plate, a movable apertured plate with an elongate nozzle extending downwardly therefrom. A main housing secured to the bottom of the ladle provides a slideway for a spring box carriage secured within the slideway. The spring box carriage carries and biases the movable apertured plate against the stationary apertured plate. A hydraulic piston or the like moves the spring box carriage within the main housing to bring the apertures into and out of registery. A plenum box extends downwardly from and is secured to the underside of the spring box carriage and is carried thereby. The plenum box has an opening in the top thereof to receive the downwardly extending elongate nozzle and means to form a rough seal around the periphery of the nozzle where it extends through the top of the plenum box. A bracket is fixed to the plenum box and extends thereaway for supporting the actuating mechanism comprising a shaft pivotally secured in the said bracket with a crank arm and lifting forks fixed to the shaft. (Alternatively, the shaft may be secured to the bracket by two rotating arms, which arms are pivotally secured to the bracket. In this case, the actuating mechanism is secured directly to the shaft without the need of a crank arm.) A hood is arranged to be telescoped over the plenum box having trunnions extending therefrom for engaging the distal ends of the lifting forks. The hood also has a flanged skirt extending downwardly from the lower edge thereof. A pneumatic or hydraulic piston or the like extending from the bracket causes rotation of the shaft thus causing the distal ends of the lifting forks to travel through an arcuate path raising and lowering the hood. According to a preferred embodiment, the hood is provided with a separate top plate or ring with an aperture therein. The top plate slidably engages the top surface of the hood and slides horizontally relative to the remainder of the hood. Thus raising and lowering of the hood through its arcuate path by rotation of the shaft does not cause binding of the hood on the plenum box, while minimizing the clearance annulus through which gas may escape. THE DRAWINGS Further features and other objects and advantages of this invention will become clear from the following detailed description made with reference to the drawings in which FIG. 1 is an overall view of a ladle with a slide gate and an ingot mold with the shroud apparatus according to this invention shown therebetween in partial section; FIG. 2 is a perspective of the plenum box with attached brackets according to this invention; FIG. 3 is a broken away section taken along lines III--III of FIG. 2; FIG. 4 is an exploded perspective of the hood assembly according to this invention; FIG. 5 is a perspective view of the actuating mechanism for raising and lowering the hood; and FIG. 6 is a broken away side view of a preferred hood with a partially insulated flange. DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, there is shown a portion of a ladle 10 having a steel shell 11 and a refractory lining 12. An opening in the base of the ladle passes through both shell and lining. Mounted to the shell 11 adjacent the opening is a slide gate 13 of typical construction. (The minor details of the ladle and the slide gate form no part of this invention.) Positioned below the slide gate 13 (shown in the open position) is an ingot mold 14 having a permanent hot top 15 positioned thereon. The use of hot tops is not essential in the practice of this invention. Thus, throughout the specification and claims herein the surface onto which the top pour shroud according to this invention is brought to rest is referred to as the "top of the mold or hot top". The slide gate 13 has a fixed apertured plate 21 firmly secured below the opening in the bottom of the ladle by slide gate housing 20. The slide gate housing 20 defines a slideway in which spring box carriage 22 is slidably positioned. The spring box carriage holds the moving apertured plate 23 with an elongate nozzle extension 24 pendant therefrom with the nozzle bore aligned with the aperture in the moving apertured plate. It is a feature according to this invention that the nozzle extension is made sufficiently long to cooperate with the plenum box and hood (to be described). By moving the aperture of the plate 23 into registry with the aperture in the plate 21, the gate is placed in its open or dispensing position as shown in FIG. 1. By moving the apertures out of registry, the gate is closed. The elongate nozzle extension 24 by itself is not new. However, the use of an elongate nozzle extension in conjunction with slow (throttled) pouring has substantial benefits. The throttled (partly open gate) results in a non-full nozzle extension below it and insures absence of a suction condition at the sliding surfaces of the gate. The elongate nozzle extension appears to collimate the flow of molten metal avoiding an otherwise rather splashy flow. The spring box carriage is provided with means for biasing the moving apertured plate 23 tightly up against the fixed plate 21 to prevent leakage of hot metal between the plates but to permit the relative sliding movement required for opening and closing the gate. The springs (not shown) effecting the bias are positioned within the spring box carriage 22. Thus, the spring box carriage itself slides directly against the slideway in the slide gate housing 20. Typically the length of travel of the moving plate is six inches. A rod 25 engates a piston from an extensible hydraulic device (not shown) for moving the spring box carriage through its travel. The specific improvement in an apparatus according to this invention is fixed to the bottom of the spring box carriage 22 and is carried back and forth by it. The shroud assembly comprises a plenum box assembly 30, a hood assembly 40 and actuating mechanism 50 for moving the hood relative to the plenum box. The details of the plenum box assembly 30 are best understood by reference to FIGS. 2 and 3. A main plate 31 has an opening therein through which the nozzle extension 24 passes. The main plate is shown elongate with the long axis thereof extending in the direction of slide gate motion. The opening has a conical interior edge 33 which is arranged to be adjacent a conical exterior edge of the nozzle (see FIG. 1). An asbestos or refractory fiber gasket may be placed along the conical interior edge 33 to provide a near gas tight seal between the main plate 31 and the nozzle extension 24. On top of the main plate are two spacer blocks 34 which may be permanently attached to the main plate having bores therein for aligning with bores in the main plate. Bolts (see FIG. 1) pass up through the main plate and the spacer blocks for securing the plenum box assembly to the bottom of the spring box carriage 22. The bolts are secured in threaded bores provided in the underside of the spring box carriage. The spacers are arranged near the opening in a way not to restrict the travel of the spring box carriage between its full open and full closed position. In other words, the bottom of the slide gate housing 20 has a rectangular opening therein with a width narrower than the width of the spring box carriage 22. The nozzle extension 24 and the spacer blocks 34 must move within the rectangular opening. Pendant from the main plate 31 is the plenum box tube 35. The axial length of the tube is such that it extends downwardly just beyond the lower end of the nozzle extension (say, one to two inches). The diameter of the tube is not critical but may be about as great as the axial length thereof. Near the lower end of the tube 35 is positioned a diaphragm 36 having an opening therein for passage of the nozzle extension. A refractory lining 37 is provided on the underside of the diaphragm to protect it from sparks and splashes. In the specific embodiment illustrated, the lower surface of the refractory lining on the diaphragm is funnel shaped with the inner edge being adjacent the lower end of the nozzle extension. The width of the gap between the outer surface of the nozzle extension and the diaphragm is approximately 1/4 to 1 inch. This is arranged to provide flow of inert gas out of the plenum along the teeming metal stream and into the hood assembly 40. The main plate, spacers, tube and diaphragm may be fabricated of carbon steel and joined by welding. A bore in the top of the plenum box with an associated fitting 32 enables a source of inert gas to introduce inert gas to the interior of the tube. Still referring to FIG. 2, brackets 38 are secured to main plate 31 and extend away from the tube 35. The brackets support bearing blocks 39 which are provided with shaft receiving bores. Referring to FIG. 4, the hood assembly 40 comprises a rectangular or otherwise shaped hollow steel box 41 having downwardly extending sidewalls 42 and a cover 43. The cover has an opening therein having a diameter just greater (say, 3/8 to 1 inch) than the outer diameter of the tube 35. The sidewall and cover are provided with a refractory lining 44 to protect against sparks and splashes. The distance from the cover to the lower edges of the sidewalls is preferably just less than the length of the tube 35 permitting the lower edge of the hood to rise to or just above the lower end of the tube as will be explained. Preferably, the dimensions of the lower edges of the sidewalls are such that they may be positioned over the upper edges of an ingot mold or hot top. In this way, all of the heat radiating from the molten metal in the ingot mold is directed at a refractory lined surface. If the dimensions are much larger, the aligned hood would have nothing to rest its lower edges upon during teeming. If the dimensions are much less, the skirt flange 45 will be exposed to heat radiating up out of the ingot mold during teeming. The skirt flange 45 extends horizontally outward from at least the two opposite walls which face in the directions of travel of the slide gate. As a practical matter, the skirt flange extends horizontally outward from each sidewall. Although the width of the skirt may be less, the width of the skirt flange is preferably at least as great as the stroke of the slide gate (usually about six to eight inches). The hood cover, sidewalls and skirt flange may all be fabricated from carbon steel and joined together by welding. All refractory linings described herein may be fired clay or high alumina type. Referring to FIG. 6, a preferred hood is illustrated. (Note that the refractory lining within the hood is not shown.) The flange 45 is shown with several preferred features: A plurality of gussets 45a reinforce the flange against thermal warping. Also, the portion of the web that is exposed to heat radiating from hot metal during positioning of the hood is provided with heath insulation in the form of an expanded metal insert 45b. Insulation of the hood is required where the bottom opening of the hood is not as large as the top opening of the mold. Finally, the leading edges 45c of the flange are turned up so that it will easily ride over the edges of the ingot mold. A very important feature of the hood is the provision of a narrow slot, say 1/2 inch wide, in one or more sidewalls. The slot 46 permits the visual observation of the teeming stream of hot metal. Extending outwardly from the sides of the hood are trunnions 47 (FIG. 4). The common axis of the trunnions is generally horizontal and preferably, but not essentially, perpendicular to the direction of motion of the slide gate. Generally, the axis of the trunnions passes near or intersect the axis of the tube when the hood is mounted thereon. The hood is preferably symmetrically arranged about the axis of the trunnions to be more or less balanced for naturally hanging with its cover and skirt flange horizontal. The trunnions 47 are engaged by the distal ends of forks 51 of the actuating assembly 50 (yet to be described) and support the hood relative to the plenum box assembly. To avoid binding, the opening in the cover 43 is somewhat larger than the outer diameter of the tube 35. However, the annular slot remaining permits the escape of inert gases much more rapidly than may be acceptable. Thus, an apertured plate or ring 60 is arranged to slide over the top face of the cover 43 to impede flow upwardly out of the hood through the annular slot. The ring has an inner diameter very nearly the same as that of the tube, say within 1/8 inch. This clearance is just sufficient to enable the ring to slide up and down along the tube with a necessary amount of angular cocking allowed for. The ring 60 may simply rest upon the top face of the cover 43 or it may be slidably attached thereto, for example by brackets 61 and pins 62 as shown in FIG. 4. Many other arrangements for slidable attachment are possible. They must, however, permit the sliding in the direction perpendicular to the axis of the trunnions. As the forks 51 swing to raise or lower the hood relative to the plenum box, the arcuate motion of the trunnions will cause horizontal movement (perpendicular to the trunnions) between the hood and the plenum box assembly. The sliding of the ring 60 over the cover will accommodate this relative movement. Referring now to FIG. 5, the actuating mechanism comprises shaft 52. The shaft, when journaled in bearing blocks 39, has a central portion between the bearing blocks and two end portions extending outwardly from the bearing blocks. A crank arm 53 is fixed to the center of the shaft to rotate therewith. When the entire apparatus is assembled, the crank arm is located between the bearing blocks. At the outer ends of the shaft, the forks 51 are fixed to rotate with the shaft. At the distal ends of the forks 51 are slots 54 opening downwardly for being placed over the trunnions 47 extending from the hood. A slide bolt 55 is arranged to capture the trunnions in the slot. Thus, it is possible to rapidly change hoods even when the ladle is filled with hot metal where, for example, one hood should fail or, for example, an ingot mold having a differently dimensioned top is encountered. Pivotally secured to the other end of the crank arm 53 is an expandable pneumatic device, for example, the piston 56 and cylinder 57. A single acting cylinder arranged so that pressurizing the ram raises the hood and venting the ram lets gravity lower the hood is satisfactory. The cylinder 57 has pins 58 extending laterally thereof which are journaled in the brackets 38. Thus,the piston and cylinder move in the space between the brackets. Expansion of the cylinder causes rotation of the shaft 52 moving the slotted ends of the forks 51 upward. In this way, the hood can be telescoped over the tube in its up position. In this position, the bottom of the nozzle extension 24 is easily inspected and, if need be, it can be cleaned with an oxygen lance as is common practice. In its lowered position, the hood 40 may rest on the top edge of an ingot mold or a hot top even if the top edge is not completely horizontal. The slots in the ends of the forks and the trunnions enable restricted rotation of the hood around two perpendicular axes. Operation Prior to the start of teeming, the ingot molds may be purged with an inert gas and covered with a burn through cover such as a cardboard or foil sheet 70. Where the puged gas is heavier than air, it is only necessary that the covering prevent the easy intermixing of atmosphere with the gas in the mold. The ladle is then aligned with the ingot mold; that is, with the fixed aperture of the slide gate directly above the ingot mold opening. The hood is then lowered so that the skirt flange rests upon the top of the mold or the hot top as the case may be. Thereafter, the slide gate may be opened, dragging the hood over the top of the mold into alignment with the mold. The inert gas is introduced into the plenum box almost continuously and certainly for a period of time after the hood has been lowered and before the slide gate is opened. Thus, the teeming steel is completely surrounded by low pressure inert gas during the entire teeming of the ingot. Having thus described the invention with the detail and particularity required by the Patent Laws, what is desired protected by Letters Patent is set forth in the following claims.

An apparatus and method for providing a protective gas shroud around molten metal being teemed from a ladle having a slide gate secured to the bottom. The apparatus comprises a plenum box sealed to and extending downwardly from the sliding part of the slide gate. A hood is arranged to telescope over the plenum box and form a rough sliding seal therewith. The hood has a skirt flange at the bottom thereof. The width of said skirt flange in the direction of movement of the slide gate is greater than the maximum slide gate movement. Means are fixed relative to the plenum box to raise and lower the hood. Means are provided for introducing a protective gas into the plenum box. The method comprises aligning the ladle with the mold into which hot metal is to be teemed. The means for raising and lowering the hood is activated to lower the skirt flange to rest upon the top of the mold or hot top. Thereafter the slide gate is opened dragging the hood over the top of the mold or hot top into alignment with the mold.

FIELD OF THE INVENTION The present invention is concerned with a class of polymer precursors with narrow molecular weight distribution and the production therefrom of physiologically soluble polymer therapeutics, functionalised polymers, pharmaceutical compositions and materials, all with similar molecular weight characteristics and a narrow molecular weight distribution. BACKGROUND OF THE INVENTION Polymer Therapeutics (Duncan R: Polymer therapeutics for tumour specific delivery Chem & Ind 1997, 7, 262-264) are developed for biomedical applications requiring physiologically soluble polymers and include biologically active polymers, polymer-drug conjugates, polymer-protein conjugates, and other covalent constructs of polymer with bioactive molecules. An exemplary class of a polymer-drug conjugate is derived from copolymers of hydroxypropyl methacrylamide (HPMA) which have been extensively studied for the conjugation of cytotoxic drugs for cancer chemotherapy (Duncan R: Drug-polymer conjugates: potential for improved chemotherapy. Anti - Cancer Drugs, 1992, 3, 175-210. Putnam D, Kopecek J: Polymer conjugates with anticancer activity. Adv.Polym.Sci., 1995, 122, 55-123. Duncan R, Dimitrijevic S, Evagorou E: The role of polymer conjugates in the diagnosis and treatment of cancer. STP Pharma, 1996, 6, 237-263). An HPMA copolymer conjugated to doxorubicin known as PK-1, is currently in Phase II evaluation in the UK. PK-1 displayed reduced toxicity compared to free doxorubicin in the Phase I studies (Vasey P, Twelves C, Kaye S, Wilson P, Morrison R, Duncan R, Thomson A, Hilditch T, Murray T, Burtles S, Cassidy J: Phase I clinical and pharmacokinetic study of PKI (HPMA copolymer doxorubicin): first member of a new class of chemotherapeutic agents: drug-polymer conjugates. Clin. Cancer Res., 1999, 5, 83-94). The maximum tolerated dose of PK-1 was 320 mg/m 2 which is 4-5 times higher than the usual clinical dose of free doxorubicin. The polymers used to develop Polymer Therapeutics may also be separately developed for other biomedical applications where the polymer conjugate is developed (e.g. as a block copolymer) to form aggregates such as polymeric micelles and complexes (Kataoka K, Kwon G, Yokoyama M, Okano T. Sakurai Y: Block copolymer micelles as vehicles for drug delivery. J. Cont.Rel., 1993, 24, 119-132. Inoue T, Chen G, Nakamae K, Hoffman A: An AB block copolymer of oligo(methyl methacrylate) and poly(acrylic acid) for micellar delivery of hydrophobic drugs. J Cont. Rel., 1998, 51, 221-229. Kwon G, Okano T: Polymeric micelles as new drug carriers. Adv. Drug Del. Rev., 1996, 21, 107-116.). The polymers used to develop Polymer Therapeutics may also be separately developed for other biomedical applications that require the polymer be used as a material rather than as a physiologically soluble molecule. Thus, drug release matrices (including microspheres and nanoparticles), hydrogels (including injectable gels and viscious solutions) and hybrid systems (e.g. liposomes with conjugated poly(ethylene glycol) (PEG) on the outer surface) and devices (including rods, pellets, capsules, films, gels) can be fabricated for tissue or site specific drug delivery. Polymers are also clinically widely used as excipients in drug formulation. Within these three broad application areas: (1) physiologically soluble molecules, (2) materials and (3) excipients, biomedical polymers provide a broad technology platform for optimising the efficacy of a therapeutic bioactive agent. Therapeutic bioactive agents which can be covalently conjugated to a polymer include a drug, peptide and protein. Such conjugation to a soluble, biocompatible polymer can result in improved efficacy of the therapeutic agent. Compared to the free, unconjugated bioactive agent, therapeutic polymeric conjugates can exhibit this improvement in efficacy for the following main reasons: (1) altered biodistribution, (2) prolonged circulation, (3) release of the bioactive in the proteolytic and acidic environment of the secondary lysosome after cellular uptake of the conjugate by pinocytosis and (4) more favourable physicochemical properties imparted to the drug due to the characteristics of large molecules (e.g. increased drug solubility in biological fluids) (Note references in Brocchini S and Duncan R: Polymer drug conjugates: drug release from pendent linkers. The Encyclopedia of Controlled Drug Delivery, Wiley, N.Y., 1999, 786-816.). Additionally, the covalent conjugation of bioactive agents to a polymer can lead to improved efficacy that is derived from the multiple interactions of one or more of the conjugated bioactive agents with one or more biological targets. Such polyvalent interactions between multiple proteins and ligands are prevalent in biological systems (e.g. adhesion of influenza virus) and can involve interactions that occur at cell surfaces (e.g. receptors and receptor clusters) (Mammen M, Choi S, Whitesides GM: Polyvalent interactions in biological systems: Implications for design and use of multivalent ligands and inhibitors. Angew. Chem. Int. Ed. 1998, 37, 2754-2794. Whitesides G, Tananbaum JB. Griffin J, Mammen M: Molecules presenting a multitude of active moieties. PCT Int. Appl. WO 9846270). Multiple simultaneous interactions of a polymer bioactive conjugate will have unique collective properties that differ from properties displayed by the separate, individual, unconjugated bioactive components of the conjugate interacting monovalently. Additionally, an appropriately functionalised polymer can interact with mucosal membranes (e.g. in the gastrointestinal, respiratory or vaginal tracts) by polyvalent interactions. Such a property is valuable for prolonged and/or preferential localisation of a functionalised polymeric excipient used for site specific delivery or altering optimally the biodistribution of a bioactive agent. Additionally polymer bioactive agent conjugates and/or aggregates can be designed to be stimuli responsive (Hoffman A, Stayton PS: Interactive molecular conjugates. U.S. Pat. No. 5,998,588), for example, to be for membranelytic after being taken up by a cell by endocytosis. These polymeric constructs must incorporate the membrane penetration features seen in natural macromolecules (toxins and transport proteins) and viruses. Cytosolic access has been shown to be rate limiting during polymer-mediated transfection (Kichler A, Mechtler A, Mechtler K, Behr JP, Wagner E: Influence of membrane-active peptides on lipospermine/DNA complex mediated gene transfer, Bioconjugate Chem., 1997, 8(2), 213-221.). Many of the cationic polymers (e.g. (poly-L-lysine) (PLL) and poly(ethyleneimine) (PEI), chitosan and cationic PAMAM dendrimers) that have been used for in vitro transfection studies are either cytotoxic (IC 50 values <50 μg/ml) or hepatotropic after i.v. injection. Such molecules are totally unsuitable for in vivo/clinical development. Alternative endosomolytic molecules have been proposed but are either too toxic (i.e. poly(ethylenimine) or potentially immunogenic (e.g. fusogenic peptides, reviewed (Plank C, Zauner W, Wagner E: Application of membrane-active peptides for drug and gene delivery across cellular membranes, Advanced Drug Delivery Reviews, 1998, 34, 21-35. Wagner E, Effects of membrane-active agents in gene delivery, J. Cont. Release, 1998, 53, 155-158.). Polymers, some with zwitterionic features, (Richardson S, Kolbe H, Duncan R: Potential of low molecular mass chitosan as a DNA delivery system: Biocompatibility, body distribution and ability to complex and protect DNA Int. J. Pharm., 1999 178, 231-243. Richardson S, Ferruti P, Duncan R: Poly(amidoamine)s as potential endosomolytic polymers: Evaluation of body distribution in normal and tumour baring animals, J. Drug Targeting, 1999) have been shown to have considerable potential for membranelytic activity as a function of pH which could be capable of rupturingthe endosome to gain access to the ctyosolic environment of cells. For the treatment of cancer there are marked improvements in therapeutic efficacy and site specific passive capture through the enhanced permeability and retention (EPR) effect (Matsumura Y, Maeda H: A new concept for macromolecular therapeutics in cancer chemotherapy; mechanism of tumoritropic accumulation of proteins and the antitumour agent SMANCS. Cancer Res., 1986, 6, 6387-6392.). The EPR effect results from enhanced permeability of macromolecules or small particles within the tumour neovasculature due to leakiness of its discontinuous endothelium. In addition to the tumour angiogenesis (hypervasculature) and irregular and incompleteness of vascular networks, the attendant lack of lymphatic drainage promotes accumulation of macromolecules that extravasate. This effect is observed in many solid tumours for macromolecular agents and lipids. The enhanced vascular permeability will support the demand of nutrients and oxygen for the unregulated growth of the tumour. Unless specifically addressed for tumour cell uptake by receptor-medicated endocytosis, polymers entering the intratumoural environment are taken up relatively slowly by fluid-phase pinocytosis. Whereas cellular uptake of low molecular weight molecules usually occurs by rapid transmembrane passage, the uptake of pysiologically soluble polymers occurs almost exclusively by endocytosis (Mellman I: Endocytosis and molecular sorting. Ann. Rev. Cell Develop. Biol., 1996, 12, 575-625. Duncan R, Pratten M: Pinocytosis: Mechanism and Regulation. In: Dean R, Jessup W, eds. Mononuclear Phagocytes: Physiology and Pathology. Amsterdam: Elsevier Biomedical Press, 1985; 27-51.). Polymer bioactive conjugates can additionally include a conjugated bioactive agent that would induce receptor-mediated endocytosis (Putnam D, Kopecek J: Polymer conjugates with anticancer activity. Adv.Polym.Sci., 1995, 122, 55-123. Duncan R: Drug-polymer conjugates: potential for improved chemotherapy. Anti - Cancer Drugs, 1992, 3, 175-210.). For example, HPMA copolymer-doxorubicin containing additionally galactosamine localises selectively in the liver due to uptake by the hepatocyte asialoglycoprotein receptor (Duncan R, Seymour L, Scarlett L, Lloyd J, Rejmanova P, Kopecek J: N-(2-Hydroxypropyl)methacrylamide copolymers with pendant galactosamine residues. Fate after intravenous administration to rats. Biochim. Biophys. Acta., 1986, 880, 62-71. Seymour L, Ulbrich K, Wedge S, Hume I, Strohalm J, Duncan R: N-(2hydroxypropyl)methacrylamide copolymers targeted to the hepatocyte galactose-receptor: pharmacokinetics in DBA-2 mice. Br. J. Cancer, 1991, 63, 859-866.). Enhanced vascular permeability is well known to be present within tissue which has undergone an inflammatory response due to infection or autoimmunedisease. Conjugates of polymers and appropriate bioactive agents could also exploit the vascular premeability gradient between healthy and inflammed tissue in these conditions leading to the passive and preferential accumulation of the conjugate at the inflammed site similar to that observed which has been shown at tumour sites in cancer. Polymer bioactive conjugates designed to be therapeuctically efficacious by multivalent interactions are being developed as agonists, partial agonists, inverse agonists and antagonists for a multitude of clinical applications including the treatment of diseases such as cancer and infection (Griffin JH, Judice JK: Novel multi-binding therapeutic agents that modulate enzymatic processes, WO 99/64037. Yang G, Meier-Davis S, Griffin JH:Multivalent agonists, partial agonists, inverse agonists and antagonists of the 5-HT3 receptors, WO 99/64046. Christensen BG, Natarajan M, Griffin JH: Multibinding bradykinin antagonists, WO 99/64039. Fatheree P. Pace JL, Judice JK, Griffin JH: Preparation of multibinding Type II topoisomerase inhibitors as antibacterial agents, WO 99/64051. Linsell MS, Meier-Davis S, Griffin JH: Multibinding inhibitors of topoisomerase, WO 99/64054. Griffin JH, Moran EJ, Oare D: Novel therapeutic agents for macromolecular structures. PCT Int. Appl. WO 9964036. Griffin JH, Judice JK: Linked polyene macrolide antibiotic compounds and uses, WO 99/64040. Choi S, Mammen M, Whitesides GM, Griffin JH: Polyvalent presenter combinatorial libraries and their uses, WO 98/47002.). The four main parts of a polymer-bioactive agent conjugate are (1) polymer, (2) bioactive agent conjugating linker which can be either a pendent chain conjugating linker or a mainchain terminating conjugating linker, (3) solution solubilising pendent chain and (4) the conjugated bioactive agent. While each component has a defined biological function, the sum is greater than the parts because these four components together as a conjugate produce a distinct profile of pharmacological, pharmacokinetic and physicochemical properties typical of physiologically soluble polymer-bioactive agent conjugates. The polymer is not a mere carrier for the bioactive agent. The polymer component of the conjugate can be synthetic or naturally derived. Synthetically derived polymers have the advantage that structure property correlations can be more effectively modulated and correlated in unique ways (Brocchini S, James K, Tangpasuthadol V, Kohn J: Structure-property correlations in a combinatorial library of degradable biomaterials. J. Biomed. Mater. Res., 1998, 42(1), 66-75. Brocchini S, James K, Tangpasuthadol V, Kohn J: A Combinatorial Approach For Polymer Design. J. Am. Chem. Soc., 1997, 119(19), 4553-4554.). The solution properties of the polymer are directly responsible for defining the circulation half-life, rate of cellular uptake, minimising deleterious side effects of potent cytotoxic drugs and imparting favourable physicochemical properties (e.g. increasing the solubility of lipophilic drugs). The solution properties of a polymer bioactive agent conjugate will be influenced by the structure of the polymer, the conjugating linker and the property modifying pendent chain. Also the amount or loading of the bioactive agent will affect the solution properties of a polymer bioactive conjugate. The solution properties of the conjugate will affect the ultimate biological profile of the conjugate. Solution properties will contribute to the biocompatibility and rate of clearance of polymer bioactive agent conjugates. Biocompatibility includes the lack of conjugate binding to blood proteins and the lack of a immunogenic response. The conjugate will display a plasma clearance which is primarily governed by the rate of kidney glomerular filtration and the rate of liver uptake. Macromolecules of molecular weight of 40,000-70,000 Da, depending on solution structure, readily pass through the kidney glomerulus and can be excreted. However, as the solution size of a molecule increases with molecular weight (or by forming supramolecular aggregates), extended blood clearance times result. Structural features including polymer flexibility, charge, and hydrophobicity affect the renal excretion threshold for macromolecules within this size range (Duncan R, Cable H, Rypacek F, Drobnik J, Lloyd J: Characterization of the adsorptive pinocytic capture of a polyaspartamide modified by the incorporation of tyramine residues. Biochim. Biophys. Acta, 1985, 840, 291-293.). Neutral, hydrophilic polymers including HPMA copolymers, polyvinylpyrrolidone (PVP) and poly(ethylene glycol) (PEG) have flexible, loosely coiled solution structures whereas proteins tend to be charged and exhibit more compact solution structures. For example, the molecular weight threshold limiting glomerular filtration of HPMA copolymer-tyrosinamide in the rat was approximately 45,000 Da (Seymour L, Duncan R, Strohalm J, Kopecek J: Effect of molecular weight (Mw) of N-(2-hydroxypropyl)methacrylamide copolymers on body distributions and rate of excretion after subcutaneous, intraperitoneal and intravenous administration to rats. J. Biomed. Mater. Res., 1987, 21, 1341-1358.) and the threshold for proteins is approximately 60K Da. Copolymers HPMA have been extensively studied for the conjugation of cytotoxic drugs for cancer chemotherapy (Duncan R, Dimitrijevic S, Evagorou E: The role of polymer conjugates in the diagnosis and treatment of cancer. STP Pharma, 1996, 6, 237-263. Putnam D, Kopecek J: Polymer conjugates with anticancer activity. Adv.Polym.Sci., 1995, 122, 55-123. Duncan R: Drugolymer conjugates: potential for improved chemotherapy. Anti - Cancer Drugs, 1992, 3, 175-210.). The homopolymer of HPMA is soluble in biological fluids, readily excreted at molecular weights of less than 40,000 Da [4], is non-toxic up to 30 glkg, does not bind blood proteins [5], and is not immunogenic (Rihova B, Ulbrich K, Kopecek J, Mancal P: Immunogenicity of N-(2-hydroxypropyl)methacrylamide copolymers-potential hapten or drug carriers. Folia Microbioa., 1983, 28, 217-297. Rihova B, Kopecek J, Ulbrich K, Chytry V: Immunogenicity of N-(2-hydroxypropyl)methacrylamide copolymers. Makromol. Chem. Suppl., 1985, 9, 13-24. Rihova B, Riha I: Immunological problems of polymer-bound drugs. CRC Crit. Rev. Therap. Drug Carrier Sys., 1985, 1, 311-374. Rihova B, Ulbrich K, Strohalm J, Vetvicka V, Bilej M, Duncan R, Kopecek J: Biocompatibility of N-(2-hydroxypropyl)methacrylamide copolymers containing adriamycin. Immunogenicity, effect of haematopoietic stem cells in bone marrow in viva and effect on mouse splenocytes and human peripheral blood lymphocytes in vitro. Biomaterials, 1989, 10, 335-342.) Like poly(ethylene glycol) (PEG) which is generally recognised as safe (GRAS) and is used for the conjugation of proteins, HPMA is biocompatible and is thus a good candidate polymer for conjugation with bioactive agents. Since HPMA copolymers are hydrophilic, solublisation of hydrophobic drugs is possible. Since each HPMA copolymer conjugate is a different copolymer, other hydrophilic polymers similar to HPMA may be good candidate polymers for the conjugation of bioactive agents. Additionally, the molecular weight characteristics of a polymer-bioactive agent conjugate will influence the ultimate biological profile of the conjugate. Biodistribution and pharmacological activity are known to be molecular weight-dependent. For example, blood circulation half-life (Cartlidge S, Duncan R. Lloyd J, Kopeckova-Rejmanova P, Kopecek J: Soluble crosslinked N-(2-hydroxypropyl)methacrylamide copolymers as potential drug carriers. 2. Effect of molecular weight on blood clearance and body distribution in the rat intravenous administration. Distribution of unfractionated copolymer after intraperitoneal subcutaneous and oral administration. J Con. Rel., 1986, 4, 253-264.), renal clearance, deposition in organs (Sprincl L, Exner J, Sterba 0, Kopecek J: New types of synthetic infusion solutions III. Elimination and retention of poly[N-(2-hydroxypropyl)methacrylamide] in a test organism. J. Biomed. Mater. Res., 1976, 10, 953-963.), rates of endocytic uptake (Duncan R. Pratten M, Cable H, Ringsdorf H, Lloyd J: Effect of molecular size of 125l-labelled poly(vinylpyrrolidone) on its pinocytosis by rat visceral yolk sacs and peritoneal macrophages. Biochem. J., 1981, 196, 49-55. Cartlidge S, Duncan R, Lloyd J, Rejmanova P, Kopecek J: Soluble crosslinked N2-hydroxypropyl)methacrylamide copolymers as potential drug carriers. 1. Pinocytosis by rat visceral yolk sacs and rat intestinal cultured in vitro. Effect of molecular weight on uptake and intracellular degradation. J. Cont. Rel., 1986, 3, 55-66.) and biological activity can depend on polymer molecular weight characteristics (Kaplan A: Antitumor activity of synthetic polyanion. In: Donaruma L, Ottenbrite R. Vogl O, eds. Anionic Polymeric Drugs. New York: Wiley, 1980; 227-254. Ottenbrite R, Regelson W, Kaplan A, Carchman R, Morahan P, Munson A: Biological activity of poly(carboxylic acid) polymers. In: Donaruma L, Vogi O, eds. Polymeric Drugs. New York: Academic Press, 1978; 263-304. Butler G: Synthesis, characterization, and biological activity of pyran copolymers. In: Donaruma L, Ottenbrite R, Vogl O, eds. Anionic Polymeric Drugs. New York: Wiley, 1980; 49-142. Muck K, Rolly H, Burg K: Makromol. Chem., 1977, 178, 2773. Muck K, Christ O, Keller H: Makromol. Chem., 1977, 178, 2785. Seymour L: Synthetic polymers with intrinsic anticancer activity. J. Bioact. Compat. Polymers, 1991, 6, 178-216.). In clinical applications requiring the cellular uptake of a polymeric bioactive agent conjugate with subsequent release of the bioactive agent intracellularly, the linker must be designed to be degraded to release the bioactive agent at an optimal rate within the cell. It is preferable that a the bioactive agent conjugating linker does not degrade in plasma and serum (Vasey P, Duncan R, Twelves C, Kaye S, Strolin-Benedetti M, Cassidy J: Clinical and pharmacokinetic phase 1 study of PK1(HPMA) copolymer doxorubicin. Annals of Oncology, 1996, 7, 97.). Upon endocytic uptake into the cell, the conjugate will localise in the lysosomes. These cellular organalles contain a vast array of hydrolytic enzymes including proteases, esterases, glycosidases, phosphates and nucleases. For the treatment of cancer, potent cytotoxic drugs have been conjugated to polymers using conjugation linkers that degrade in the lysosome while remaining intact in the bloodstream. Since many drugs are not pharmacologically active while conjugated to a polymer, this results in drastically reduced toxicity compared to the free drug in circulation. The conjugating linker structure must be optimised for optimal biological activity. Incorporation of a polymer-drug linker that will only release drug at the target site can reduce peak plasma concentrations thus reducing drug-medicated toxicity. If the drug release rate is optimised, exposure at the target can be tailored to suit the mechanism of action of the bioactive agent being used (e.g. use of cell-cycle dependent antitumour agents) and to prevent the induction of resistance. To be effective, it is important that polymer bioactive agent conjugates are designed to improve localisation of the bioactive agent in the target tissue, diminish deleterious exposure in potential sites of toxicity in other tissue and to optimise the release rate of the bioactive agent in those applications where its release is required for a biological effect. The rate of drug release from the polymer chain can also vary according to the polymer molecular weight and the amount of drug conjugated to the polymer. As greater amounts of hydrophobic drug are conjugated onto a hydrophilic polymer, the possibility to form polymeric micelles increases (Ulbrich K, Konak C, Tuzar Z, Kopecek J: Solution properties of drug carriers based on poly[N-(2hydroxypropyl)methacrylamide] containing biodegradable bonds. Makromol. Chem., 1987, 188, 1261-1272.). Micellar conjugate structures may hinder access of the lysosomal enzymes to degrade the linker and release the conjugated drug. Additionally, hydrophilic polymers conjugated to hydrophobic drugs can exhibit a lower critical solution temperature (LCST) where phase separation occurs and the conjugate becomes insoluble. Simple turbidometric assays (Chytry V, Netopilik M, Bohdanecky M, Ulbrich K: Phase transition parameters of potential thermosensitive drug release systems based on polymers of N-alkylmethacrylamides. J. Biomater. Sci. Polymer Ed., 1997, 8(11), 817-824.) have been used as a preliminary screen to determine the propensity for phase separation at various HPMA copolymer-doxorubicin conjugates of different molecular weight and drug loading (Uchegbu F, Ringsdorf H, Duncan R: The Lower Critical Solution Temperature of Doxorubicin Polymer Conjugates. Proceed. Intern. Symp. Control. Rel. Bioact. Mater., 1996.). As a bioactive agent is released from a polymer due to linker degradation it would be expected that changes in polymer conformation will occur that might also lead to diffences in drug release rate with time (Pitt C, Wertheim J, Wang C, Shah S: Polymer-drug conjugates: Manipulation of drug delivery kinetics. Macromol. Symp., 1997, 123, 225-234. Shah S, Werthim J, Wang C, Pitt C: Polymer-drug conjugates: manipulating drug delivery kinetics using model LCST systems. J. Cont. Rel., 1997, 45, 95-101.)and therefore pharmacological properties. The extent of drug loading and its influence on polymer solution properties is an important, and yet poorly understood phenomenon which must be correlated to structure-property relationships of the polymer-bioactive agent conjugate to lead to optimisation of the the in viva biological properties of therapeutic polymer bioactive agent conjugates. Currently HPMA copolymer-drug conjugates are prepared by a polymer analogous reaction of a low molecular weight drug (e.g. doxorubicin) with a copolymeric precursor which incorporates both the bioactive agent conjugating linker and the solution solubilising pendent chain (Rihova B, Ulbrich K, Strohalm J, Vetvicka V, Bilej M, Duncan R, Kopecek J: Biocompatibility of N-(2-hydroxypropyl)methacrylamide copolymers containing adriamycin. Immunogenicity, effect of haematopoietic stem cells in bone marrow in viva and effect on mouse splenocytes and human peripheral blood lymphocytes in vitro. Biomaterials, 1989, 10, 335-342. Kopecek J, Bazilova H: Poly[N-(hydroxypropyl)methecrylamide]-I. Radical polymerisation and copolymerisation. Eur. Polymer J., 1973, 9, 7-14. Strohalm J, Kopecek J: Poly[N-(2-hydroxypropyl)methacrylamide] IV. Heterogeneous polymerisation. Angew. Makromol. Chem., 1978, 70, 109-118. Rejmanova P, Labsky J, Kopecek J: Aminolyses of monomeric and polymeric 4-nitrophenyl esters of N-methacryloylamino acids. Makromol. Chem., 1977, 178, 2159-2168. Kopecek J: Reactive copolymers of N-(2-Hydroxypropyl)methacrylamide with N-methacryloylated derivatives of L-leucine and L-phenylalanine. Makromol. Chem., 1977, 178, 2169-2183. Kopecek J: The potential of water-soluble polymeric carriers in targeted and site-specific drug delivery. J. Cont. Rel., 1990, 11, 279-290.). The vast majority of polymer bioactive agent conjugates prepared by the polymer analogous reaction are prepared by the reaction of the bioactive agent with a copolymeric precursor (Note references in Brocchini S and Duncan R: Polymer drug conjugates: drug release from pendent linkers. The Encyclopedia of Controlled Drug Delivery, Wiley, N.Y., 1999, 786-816.). The disadvantage of using a copolymer precursor is that for each change in the structure or relative amounts of (1) the bioactive agent conjugating linker or (2) the solution solubilising pendent chain, a new copolymeric precursor must be prepared. Since pendent chain structure is important for the biological profile of a polymer bioactive agent a copolymeric precursor is required to study each conjugate possessing modified conjugating linkers. Solution structure is a function of all the structural features of a bioactive agent polymer conjugate. To elucidate the solution-structure correlations of either the polymer mainchain, conjugating linker or solution solubilising pendent chain requires a different copolymer precursor for each variation of each component. It is not possible to even use the same copolymeric precursor to vary the amount or loading of the conjugated bioactive agent. If loading of the bioactive agent is to be varied and is to be less than the relative stoichiometry of the conjugating pendent chain, then the remaining conjugating pendent chains will not be conjugated to a drug, and the remaining conjugating pendent chains will be terminate with some other inert molecule. The polymer analogous reaction requires that the copolymeric precursor possess functionality on the conjugation pendent chain termini that is reactive (e.g. a p-nitrophenol active ester of a carboxylic acid) so that upon addition of a bioactive agent, the agent will form a covalent bond with the conjugation pendent chain to become linked to the polymer. Thus if a loading of the bioactive agent is to be less than the relative stoichiometry of the conjugating pendent chain, the reactive functionality must be quenched with a reagent other than the bioactive agent or preferably in this situation, a new polymeric precursor be prepared. These procedures tend to produce polymer conjugates with a wide distribution of structures. It thus becomes impossible to accurately determine structure-property correlations. Clearly, if a loading of the bioactive agent greater than the relative stoichiometry of the conjugation pendent chain is desired, then another copolymeric precursor must be prepared. Since many polymer bioactive agent conjugates are co-poly-(methacrylamides), the polymer analogous reaction is conducted on a co-poly(methacrylamide) precursor. It is not possible to make the vast majority of such precursors with a narrow molecular weight distribution with a polydisperisty index of less than 2 except in special cases where a copolymer precursor happens to precipitate from the polymerisation solution at a molecular weight below the renal threshold. It is also not possible to make several different copoly(methacrylamides) all possessing the same molecular weight characteristics, e.g. all possessing the same degree of polymerisation and the same molecular weight distribution. The copoly-(methacrylamide) precursors tend to be prepared by free radical polymerisation which typically produce random copolymers typically with a polydisperisity (PD)>1.5-2.0. Furthermore since the relative stoichiometry of the conjugated bioactive agent, and thus the conjugating linker, is less than the solution solubilising pendent chain, the polymer analogous reaction is frequently on a copolymer precuresor with a low relative stoichiometry of reactive sites for the conjugation of the bioactive agent. This inefficient conjugation strategy is often burdened with competitive hydrolysis reactions and other consuming side reaction that result in conjugating linkers not covalently linked to the bioactive agent (Mendichi R, Rizzo V, Gigli M, Schieroni A G: Molecular characterisation of polymeric antitumour drug carriers by size exclusion chromatograpgy and universal calibration. J. Liq. Chrom. and Rel. Technol., 1996, 19(10), 1591-1605. Configliacchi E, Razzano G, Rizzo V, Vigevani A: HPLC methods for the determination of bound and free doxorubicin and of bound and free galactosamine in methacrylamide polymer-drug conjugates. J. Pharm. Biomed. Analysis, 1996, 15, 123-129.). This not only causes significant structure heterogenaity between batches, but also causes significant waste of the bioactive agent because it has not been conjuated and its recovery is too expensive. In the case of conjugate developed for endocytic uptake into a cell, the lysosomal degradation of bioactive agent conjugating pendent chains with pendent chains not linked to the bioactive pendent chain. This competition complicates the pharmacology and pharmacokinetics of the polymer bioactive agent conjugate. Polymer-bioactive agent conjugates and biomedical polymers currently used for medical applications are, from the perspective of regulatory agencies (e.g. Medicines Control Agency, FDA) not structurally defined. Many conjugates display broad molecular weight distribution and random incorporation of the conjugated bioactive agent. Frequently, the structure of the conjugating linker is varied due to racimisation or incomplete conjugation of the bioactive agent to each of the conjugating linkers. Future development of physiologically soluble polymers used in the development of polymer-bioactive agent conjugates (i.e. polymer therapeutics) requires that more defined conjugate structures be prepared for study. In this way it will become possible to more accurately elucidate structure-property correlations that influence the biological profile of these macromolecular therapeutics. This is not possible by conducting the polymer analogous reaction on many different copolymeric precursors. There is a need to prepare polymer-bioactive conjugates which have a more narrow molecular weight distribution than are currently available. There is also a need to ensure that each bioactive conjugating linker is structurally the same and is covalently bound to the polymer and the bioactive agent. Additionally there is a need for a more efficient strategy in preclinical development where conjugates with similar molecular weight characteristics are prepared for study and where solution properties can also be varied without changing the molecular weight characteristics of the polymer mainchain. Since HPMA copolymer conjugates are poly(methacrylamides) then any techniques developed that will meet the requirements to prepare such conjugates can also be used to prepare other poly(methacrylates) for other healthcare and consumer applications where the resultant polymer can be used either as a soluble molecule, processible material that can be fabricated into a device or as an excipient. Since only a small limited number of acrylamide homo- and co-polymers with narrow molecular weight distribution can be prepared, then for speciality applications there is need for processes that provide a means to prepare such polymers. These limitations for conducting the polymer analogous reaction on a copolymer precursor can be alleviated by conducting the polymer analogous reaction with a homopolymeric precursor that has a narrow molecular weight distribution and where each repeat unit is reactive site. Conjugation of a bioactive agent or a derivative is carried out in a first reaction to covalently link the bioactive agent to the polymer. The conjugation is efficient because each repeat unit on the homopolymer precursor is a reactive site available for reaction. Upon conjugation of the bioactive agent, the intermediate precursor is a copolymer comprised of most repeat units being terminated still with a reactive chemical functional group. These are are then allowed to react with a reagent which will become the solution solubilising pendent chain in the final conjugate. By using one such narrow molecular weight distribution homopolymeric precursor it becomes possible to prepare many copolymer conjugates all possess the same narrow molecular weight distribution. Each conjugate will also possess the same molecular weight characteristics of the degree of polymerisation and polydispersity index that the homopolymeric percursor possesses. This invention is concerned with the synthesis by controlled radical polymerisation processes (Sawamoto M, Masami K: Living radical polymerizations based on transition metal complexes. Trends Polym. Sci. 1996, 4, 371-377. Matyjaszewski K:, Mechanistic and synthetic aspects of atom transfer radical polymerization. Pure Appl. Chem. 1997, A34, 1785-1801. Chiefari J, Chong Y, Ercole F, Krstina J, Jeffery J, Le T, Mayadunne R, meijs G, Moad C, Moad G, Rizzardo E, Thang S: Living free-radical, polymerization by reversible addition-fragmentation chain transfer: the RAFT process. Macromolecules, 1998, 31, 5559-5562. Benoit D, Chaplinski V, Braslau R. Hawker C: Development of a universal alkoxyamine for “living” free radical polymerizations. J. Am. Chem. Soc., 1999, 121, 3904-3920.) of narrow molecular weight distribution homopolymer precursors with a polydispersity index of less than 1.2. These controlled radical polymerisation processes have so far not been shown to give directly acrylamide homo- and co-polymers with narrow molecular weight distribution. This invention is also concerned with the use of these homopolymeric precursors to prepare physiologically soluble polymer bioactive agent conjugates, polymer therapeutics, functionalised polymers, pharmaceutical compositions and materials. SUMMARY OF THE INVENTION One embodiment of the present invention provides a polymer comprising the unit (I) wherein R is selected from the group consisting of hydrogen, C 1 -C 18 alkyl, C 1 -C 18 alkenyl, C 1 -C 18 aralkyl, C 1 -C 18 alkaryl, carboxylic acid, carboxy-C 1-6 alkyl, or any one of C 1 -C 18 alkyl, C 1 -C 18 alkenyl, C 1 -C 18 aralkyl, C 1 -C 18 alkaryl substituted with a heteroatom within, or attached to, the carbon backbone; R 1 is selected from the group consisting of hydrogen, C 1 -C 6 alkyl groups; X is an acylating group and wherein the polymer has a polydispersity of less than 1.4, preferably less than 1.2 and a molecular weight (Mw) of less than 100,000. The acylating group X is preferably a carboxylate activating group and is generally selected from the group consisting of N-succinimidyl, pentachlorophenyl, pentafluorophenyl, para-nitrophenyl, dinitrophenyl, N-phthalimido, N-norbornyl, cyanomethyl, pyridyl, trichlorotriazine, 5-chloroquinilino, and imidazole. Preferably X is an N-succinimidyl or imidazole moiety. Preferably R is selected from the group consisting of hydrogen, C 1 -C 6 alkyl, C 1 -C 6 alkenyl, C 1 -C 6 aralkyl and C 1 -C 6 alkaryl, C 1 -C 6 alkylamido and C 1 -C 6 alkylamido. Most preferably R is selected from hydrogen or methyl. Preferably R 1 is selected from the group consisting of hydrogen, methyl, ethyl, propyl, butyl, pentyl or isomers thereof. Most preferably R 1 is selected from hydrogen or methyl. The polymer of the present invention may be a homopolymer incorporating unit (I), or may be a copolymer or block copolymer incorporating other polymeric, oligomeric or monomeric units. For example, further polymeric units incorporated in the polymer may comprise acrylic polymers, alkylene polymers, urethane polymers, amide polymers, polypeptides, polysaccharides and ester polymers. Preferably, where the polymer is a heteropolymer, additional polymeric components comprise polyethylene glycol, polyaconitic acid or polyesters. The molecular weight of the polymer should ideally be less than 100,000, preferably 50,000 where the polymer is to be used as a physiologically soluble polymer (in order that the renal threshold is not exceeded). Preferably the molecular weight of the polymer is in the range of 50,000-4000, more preferably 25,000-40,000. Another embodiment of the present invention is a polymer comprising the unit (II) wherein R 2 is selected from hydrogen, C 1 -C 18 alkyl, C 1 -C 18 alkenyl, C 1 -C 18 aralkyl, C 1 -C 18 alkaryl, carboxylic acid and carboxy-C 1-6 alkyl; R 3 is selected from the group consisting of hydrogen, methyl, ethyl, propyl, butyl, pentyl and isomers thereof, Z is a pendent group selected from the group consisting of NR 4 R 5 , SR 6 and OR 7 , wherein R 4 is an acyl group, preferably an aminoacyl group or oligopeptidyl group; R 5 is selected from hydrogen, C 1 -C 18 alkyl, C 1 -C 18 alkenyl, C 1 -C 18 aralkyl, C 1 -C 18 alkaryl; R 6 and R 7 are selected from the group consisting of hydrogen, C 1 C 12 alkyl, C 1 -C 12 alkenyl, C 1 -C 12 aralkyl, C 1 -C 12 alkaryl, C 1 -C 12 alkoxy and C 1 -C 12 hydroxyalkyl, and may contain one or more cleavable bonds and may be covalently linked to a bioactive agent. Generally the polymer has a polydispersity of less than 1.4, preferably less than 1.2 and a molecular weight (Mw) of less than 100,000, preferably 50,000. Preferably R 2 is selected from the group consisting of hydrogen, C 1 -C 6 alkyl, C 1 -C 6 alkenyl, C 1 -C 6 aralkyl and C 1 -C 6 alkaryl, C 1 -C 6 alkylamido and C 1 -C 6 alkylamido. Preferably R 3 is selected from the group consisting of hydrogen, methyl, ethyl, propyl, butyl, pentyl or isomers thereof. Most preferably R 2 is hydrogen and R 3 is hydrogen or methyl. Z may comprise a peptidic group. Preferably Z comprises one or more aminoacyl groups, preferably 2-6 aminoacyl groups, most preferably 4 aminoacyl groups. In a particularly preferred embodiment group Z comprises a glycine-leucine-phenylalanine-glycine linkage. The aminoacyl linkage is most preferably a peptide linkage capable of being cleaved by preselected cellular enzymes, for instance, those found in liposome of cancerous cells. In another preferred embodiment group Z comprises a cis-aconityl group. This group is designed to remain stable in plasma at neutral pH (˜7.4), but degrade intracellularly by hydrolysis in the more acidic environment of the endosome or liposome (˜pH 5.5-6.5). The pendent chain Z may additionally be covalently bound to a ligand or bioactive agent. The ligand may be any ligand which is capable of polyvalent interactions. Preferred bioactive agents are anti-cancer agents such as doxorubicin, daunomycin and paclaxitol. A further preferred polymer of the present invention has the structure (III) wherein R 8 and R 9 are selected from the same groups as R 2 and R 3 respectively, Q is a solubilising groups selected from the group consisting of C 1 C 12 alkyl, C 1 -C 12 alkenyl, C 1 -C 12 aralkyl, C 1 -C 12 alkaryl, C 1 -C 12 alkoxy, C 1 -C 12 hydroxyalkyl, C 1 -C 12 alkylamido, C 1 -C 12 alkylamido, C 1 -C 12 alkanoyl, and wherein p is an integer of less than 500. Preferably Q comprises an amine group, preferably a C 1 -C 12 hydroxyalkylamino group, most preferably a 2-hydroxypropylamino moiety. This group is designed to be a solubilising group for the polymer in aqueous solutions. Generally the polymer of the present invention is a water soluble polyacrylamide homo- or copolymer, preferably a polymethacrylamide or polyethacrylamide homo- or copolymer. In a further embodiment, the present invention provides a process for the production of a polymer, comprising the polymerisation of a compound (IV) wherein R is selected from the group consisting of hydrogen, C 1 -C 18 alkyl, C 1 -C 18 alkenyl, C 1 -C 18 aralkyl, C 1 -C 18 alkaryl, carboxylic acid, carboxy-C 1-6 alkyl, or any one of C 1 -C 18 alkyl, C 1 -C 18 alkenyl, C 1 -C 18 aralkyl, C 1 -C 18 alkaryl substituted with a heteroatom within, or attached to, the carbon backbone; R 1 is selected from the group consisting of hydrogen and C 1 -C 6 alkyl groups preferably selected from the group consisting of methyl, ethyl, propyl, butyl, pentyl and isomers thereof; X is an acylating group, preferably a carboxylate activating group; wherein the process is a controlled radical polymerization, to produce a narrow weight distribution polymer comprising the unit (I) wherein n is an integer of 1 to 500. Preferably R is selected from the group consisting of hydrogen, C 1 -C 6 alkyl, C 1 -C 6 alkenyl, C 1 -C 6 aralkyl and C 1 -C 6 alkaryl, C 1 -C 6 alkanoyl, C 1 -C 6 alkylamido and C 1 -C 6 alkylamido. Preferably R 1 is selected from the group consisting of hydrogen, methyl, ethyl, propyl, butyl, pentyl or isomers thereof. Where the polymerization is carried out by atom transfer radical polymerization, a suitable radical initiator is utilised. Such initiators commonly comprise alkylhalides, preferably alkylbromides. In particular, the initiator is 2-bromo-2-methyl-(2-hydroxyethyl)propanoate. The polymerisation is also carried out in the presence of a polymerisation mediator comprising a Cu(I) complex. Such complexes are usually Cu(I)Br complexes, complexed by a chelating ligand. Typical mediators are Cu(I)Br (Bipy) 2 , Cu(I)Br(Bipy), Cu(I)Br(Pentamethyl diethylene), Cu(I)Br[methyl 6 tris(2-aminoethyl)amine] and Cu(I)Br(N,N,N′,N″,N″-pentamethyidiethylenetriamine). The reaction should take place in the presence of a suitable solvent. Such solvents are generally aprotic solvents, for example tetrahydrofuran, acetonitrile, dimethylformamide, acetone, dimethylsulphoxide, ethyl acetate, methylformamide and sulpholane and mixtures thereof. Alternatively, water may be used. Particularly preferred solvents are dimethylsulphoxide and dimethylformamide and mixtures thereof. Alternatively the polymerization may take place via Nitroxide Mediated Polymerization. Again, a suitable Nitroxide Mediated Polymerization initiator is required. Such an initiator generally has the structure wherein A is selected from the group consisting of C 1- C 12 alkyl, C 1 -C 12 alkenyl, C 1 -C 12 aralkyl, C 1 -C 12 alkaryl, C 1 -C 12 hydroxyalkyl, B and C are individually selected from the group consisting of C 1 C 12 alkyl, C 1 -C 12 alkenyl, C 1 -C 12 aralkyl, C 1 -C 12 alkaryl, C 1 -C 12 hydroxyalkyl, and may together with N form a C 1 -C 12 heterocyclic group and which may contain a heteroatom selected from nitrogen, sulfur, oxygen and phosphorus. Preferably A is selected from the group consisting of methyl, ethyl, propyl, butyl, pentyl, hexyl, benzyl, methylbenzene, ethyl benzene, propylbenzene or isomers thereof. B and C should generally be sterically crowding the groups capable of stabilising a nitroxide radical. Such groups are generally selected from the group consisting of isopropyl, isobutyl, secbutyl, tert-butyl, isopentyl, sec-pentyl, tert-pentyl, adamantyl, methylbenzene, ethyl benzene, propylbenzene or isomers thereof. Common initiators have these structures outlined below wherein R 9 to R 11 are selected from the group consisting of C 1 -C 12 alkyl, C 1 -C 12 alkenyl, C 1 -C 12 aralkyl, C 1 -C 12 alkaryl, C 1 -C 12 alkoxy, C 1 -C 12 hydroxyalkyl, C 1 -C 12 alkylamido, C 1 -C 12 alkylamido, C 1 -C 12 alkanoyl. Again, suitable solvents for use with Nitroxide Mediated Polymerisations are aprotic solvents as described above. Alternatively, water may be used. A further embodiment of the present invention provides a process for the production of a polymer, comprising the reaction of a polymer having the formula (VI) wherein R 12 is a group selected from the group consisting of hydrogen, C 1 -C 18 alkyl, C 1 -C 18 alkenyl, C 1 -C 18 aralkyl and C 1 -C 18 alkaryl groups; R 13 is selected from the group consisting of C 1 -C 6 alkyl groups; E is a carboxylate activating group and r is an integer of 5 to 500; with a reagent HR x , wherein R x is selected from the group consisting of NR 14 R 15 , SR 16 and OR 17 , wherein R 14 is an acyl group, preferably an aminoacyl group or oligopeptidyl group; R 15 is selected from hydrogen, C 1 -C 18 alkyl, C 1 -C 18 alkenyl, C 1 -C 18 aralkyl, C 1 -C 18 alkaryl; R 16 and R 17 are selected from the group consisting of hydrogen, C 1 C 12 alkyl, C 1 -C 12 alkenyl, C 1 -C 12 aralkyl, C 1 -C 12 alkaryl, C 1 -C 12 alkoxy and C 1 -C 12 hydroxyalkyl, and may contain one or more cleavable bonds, to form a derivatised polymer having the structure (VII) wherein 1≦s≦r. R 12 is preferably selected from the group consisting of hydrogen, methyl, ethyl and propyl, R 13 is selected from the group consisting of hydrogen, methyl, ethyl and propyl and preferably R 12 is hydrogen and R 13 are methyl. E is selected from the group consisting of N-succinimidyl, pentachlorophenyl, pentafluorophenyl, para-nitrophenyl, dinitrophenyl, N-phthalimido, N-norbornyl, cyanomethyl, pyridyl, trichlorotriazine, 5-chloroquinilino, and imidazole, preferably N-succinimidyl or imidazole, most preferably N-succinimidyl. Preferably HR x is H 2 NR 14 . HR x is generally a nucleophilic reagent capable of displacing E—O, to form a covalent bond with the acyl group attached to CR 3 . Preferably HR x comprises a primary or secondary amine group. Most preferably HR x comprises a cleavable bond such as a aminoacyl linkage or a cis-aconityl linkage as described hereinbefore. Generally HR x is covalently attached to a bioactive agent prior to reaction with (VI) subsequent to the production of a polymer having the structure (VII), an additional step of quenching the polymer may take place. This involves reacting the previously unreacted groups E with a quenching group. This group has the formula HR x ′, preferably comprises an amine moiety and is generally selected to be a solubilising or solubility modifying group for the polymer. Such a quenching compound is, for example a hydrophilic reagent, for example, hydroxypropylamine. DETAILED DESCRIPTION OF THE INVENTION The present invention provides a polymer having a polydispersity of less than 1.2. The polymer is preferably an activated polyacrylate ester that is prepared by Controlled Radical Polymerization. These polymers are designed to be derivitisable and may be used to form polymer-drug conjugates having improved biological profile. A particularly preferred polymer of the present invention comprises the structure (X) The activating moiety is an N-succinimidyl group. This particular group has been found to be particularly stable in solution and resists spontaneous hydrolysis. This polymer may be produced by Atom Transfer Polymerization using a Cu(I)Br(pentamethyidiethylene) mediator. The polymerization involved the reaction of a monomer (IX) with a suitable aprotic solvent. In one preferred embodiment the solvent is tetrahydrofuran. In another preferred embodiment the solvent is dimethylsulphoxide and optionally dimethylformamide in admixture thereof. The reaction is preferably carried out under a nitrogen atmosphere and at a temperature of 0-150° C. A preferred temperature range is 30-80° C., most preferably 50-70° C. The polymer comprising the unit (X) may subsequently be derivatised. The carboxyl activating group may be substituted by a suitable nucleophilic reagent. In order to form polymer drug conjugates it is preferable to derivatise unit (X) with a pendant moiety. Such a moiety could comprise a aminoacyl linkage or a hydrolytically labile linkage as defined hereinbefore. Such a linkage can degrade when entering the lysosome of a diseased cell, thus releasing a drug or drug precursor directly to the target site. Preferably a pendent moiety comprises a Gly-Leu-Phe-Gly linkage or a cis aconityl linkage. Such a pendent linkage may be covalently attached to a drug prior to polymer derivitisation or may be capable of being derivatised subsequent of attachment of the pendent moiety to the polymer backbone, In a preferred embodiment the polymer comprising the unit (X) is reacted with less than 1 equivalent of a pendent group, thus only substituting a pre-specified number of N-succinimidyl moieties. This allows a second, quenching step, which substitutes the remaining N-succinimidyl groups with a solubilising group. Such a group aids in the solubilisation of the polymer in aqueous solutions such as biological fluids. A preferred quenching agent should comprise an amine, for example 2-hydroxypropylamine. An overview of a preferred reaction process is provided in scheme 1 below. In this particular example, the drug doxorubicin is attached to the polymer via a GLFG linkage. n is an integer in the range of 1 to 500 and m is the number equivalent of pendent moieties reacted with the activated polymer. CRP processes are known to result in the presence of dormant initiating moieties at the chain ends of linear polymers. In particular the use of nitroxide mediated radical polymerization may be used to prepare narrow molecular weight distributed block copolymers. This allows more defined introduction of drug conjugating pendent chains in the polymer. Outlined in Scheme 2 is an example of this approach to prepare a block copolymer precursor using the CRP process known as nitroxide mediated polymerization (NMP). wherein x and y are the number equivalent of the pendent moiety and quenching group respectively. Thus, polymeric precursors (XI) and (XIII) are designed to be used as polymeric precursors for polymer analogous reactions that are driven to completion to prepare conjugates with narrow molecular weight distributions and with differing m and n repeat structure. Drug conjugation would be localized only in the n repeat structure. Again it is possible to vary the solubilising pendent chain and the drug conjugating pendent chain starting from the polymeric precursor (XI). Defining the location of the drug conjugating pendent chains is necessary to develop more defined polymer-drug conjugates. The extent and location of drug loading and its influence on polymer solution properties is an important, and yet poorly understood phenomenon and will have a fundamental effect on the in vivo properties of therapeutic polymer-conjugates. Thus, this approach will find utility also in the development and optimization of polymer-drug conjugates. BRIEF DESCRIPTION OF THE FIGURES FIG. 1 shows that the broad molecular weight distribution associated with conventional free radical polymerization can be greatly improved using ATP. FIG. 2 . Superimposed IR spectra of narrow MWD homopolymer precursor 3 before and after reaction with 1-amino-2-propanol. FIG. 3 . The GPC for narrow MWD polymethacrylamide 5 (Labelled “A”) derived from the reaction of precursor 3 and 1-amino-2-propanol (2.0 equivalents). The GPC labelled “B” was obtained for 5 that was prepared by conventional free radical polymerization in acetone using AIBN as initiator. FIG. 4 . Cytotoxicity assay using B16F10 cell line of narrow MWD polymethacrylamide 5 prepare from narrow MWD homopolymeric precursor 3 and polymethacrylamide 5 prepared by conventional free radical polymerisation of monomer 6. FIG. 5 . Superimposed IR spectra in the absorbance mode for the sequence of reactions to produce narrow MWD copolymer conjugate 7. FIG. 6 . Superimposed IR spectra in the absorbance mode for the sequence of reactions to produce the intermediate narrow MWD copolymer conjugate 8. FIG. 7 . Superimposed IR spectra displaying the changes in the active ester peak during this sequence of reactions to prepare conjugate 12. FIG. 8 . Preparation of narrow MWD conjugate 12 at 25% loading of 10. FIG. 9 . Preparation of narrow MWD conjugate 13 at 25% loading of 10. FIG. 10 . Preparation of narrow MWD conjugate 14 at 25% loading of 10. FIG. 11 . Preparation of narrow MWD conjugate 15 at 100% loading of 10. FIG. 12 . The GPC for narrow MWD poly(methacryloxy succinimide) 3 (Labelled “A”) that was used as the starting polymer in the chain extension reaction described in example 6. EXAMPLES Example 1 Copper(I) bromide, pentamethyidiethylene ligand, an initiator having the structure, and 2-bromo-2-methyl-(2-hydroxyethyl)propanoate and monomer (IX) were added to THF solvent is a glass flask. The resulting solution was purged with nitrogen to remove oxygen. The flask was sealed and placed in an oil bath at 70° C. for 24 Hr. Samples were prepared for gel permeation chromatography by passing through a neutral aluminium oxide column to remove copper components. Analysis reveals the production of a polymer with a molecular weight of 20,000. A sample of this activated ester homopolymer was quenched with 1-aminopropanol, to give a water soluble polymer whose 1 H NMR spectrum was consistent with that of poly(HPMA). FIG. 1 compares the gel permeation chromatograms of HPMA homopolymer prepared from conventional free radical polymerization with that of 1-aminopropanol quenched poly(methacryloylsuccinimide) prepared using atom transfer radical polymerization. Example 2 Synthesis of narrow molecular weight distribution (MWD) homo-polymeric precursor 3. (A) Homopolymerization in dimethylsulfoxide (DMSO) and dimethylformamide (DMF) and (B) Polymerisation in tetrahydrofuran (THF) and acetone. Synthesis of Methacryloxysuccinimide 1 To N-hydroxysuccinimide (6.6 g, 57 mmol) in dichloromethane (12 ml) was added dropwise a dichloromethane (12 ml) solution of methacryloyl chloride (6.0 g, 57 mmol) simultaneously with a dichloromethane solution (12 ml) of triethylamine (5.8 g, 57 mmol) maintaining the temperature below 5° C. After complete addition the reaction mixture was further stirred for 1 h and then washed with aqueous sodium hydrogen carbonate (0.1 M) and water (×3). The organic phase was then isolated and dried with magnesium sulfate. The solvent was removed to leave a white solid product which was recrystalised from ethyl acetate:hexane. Mass 8 g, m.p.=102° C. ( 1 H, 500MHz, DMSO-d 6 ): 2.00 (3H, s, CH 3 ), 2.84 (4H, s, (CH 2 ) 2 ), 6.09 (1H, s, ═CH 2 ), 6.34 (1H, s, ═CH 2 ). (A) Homogeneous Polymerisation in DMSO: Synthesis of Homopolymeric Precursor—Poly(methacryloxysuccinimide) (1→3). In a typical copper mediated polymerisation using DMSO as solvent at the preferred weight concentration of 56% in monomer 1, copper(I)bromide (31.3 mg, 0.2 mmol), 2-2′-bipyridine (Bpy) (68.3 mg, 0.4 mmol) and monomer 1 (2.00 g, 10.9 mmol) were added to a round bottomed flask which was then sealed with a septum. Into the flask was then injected DMSO (1.3 g). The resulting brown mixture was gently heated until a solution had formed and then purged with argon for approximately 5 min. An argon purged solution of 2-bromo-2-methyl-(2-hydroxyethyl)propanoate 2 (46.1 mg, 0.2 mmol) in DMSO (0.2 g) was then injected into the mixture and the flask was heated to 100° C. in an oil bath. The reaction mixture became viscous after a few minutes and was removed from the heat after 10-15 minutes and rapidly cooled. The polymeric product was isolated by addition of 7-8 ml of DMSO to dissolve the crude product mixture which was slowly added to a stirred solution of acetone (100 ml) to precipitate homopolymeric precursor 3 as a white solid. The acetone solution turned a green colour during the precipitation of polymer 3 due to the dissolution of copper species and the ligand. Atomic absorption analysis indicated the copper content in polymer 3 when at a concentration of 28.0 mg/ml in DMF to be 0.153 ppm. Precipitation of polymer 3 from the DMSO reaction solution into acetone may offer a viable alternative to alumina chromatography which has been typically used in copper mediated polymerisations to remove of copper from the product polymer. The isolated yield of polymer 3 was 1.78 g (89%). The number average molecular weight was 22,700 g/mol and polydispersity index was 1.20. Apparent molecular weights and molecular weight distributions for poly(methacryloxy succinimide) 3 were determined using Waters Styragel HR4 and HR3 (7.3×300 mm) columns coupled to a Gibson 133 refractive index detector, poly(methyl methacrylate) PMMA calibration standards and DMF with 0.1% LiCl eluent. Polymerisations were conducted with different ratios of monomer 1 and initiator 2 to give narrow MWD homopolymeric precursors 3 with different molecular weights. These experiments are listed in Table 1 and have been conducted on reaction scales ranging from 26 g in methacryloxysuccinimide 1. Note also these homogeneous polymerisation conditions in DMSO gave the polymer 3 in a matter of minutes (e.g. experiment 6 in Table 1 was quenched after 2 minutes to give a significant yield of narrow MWD polymer 3. Polymerisations were conducted at temperatures ranging from 80-130° C. to maintain solution homogeneity at methacryloxysuccinimide 1 to solvent weight ratios spanning 33-91%. The preferred solvent was DMSO, but similiar results were obtained with DMF. The weight ratio of monomer 1 to polar solvent (DMSO or DMF) was critical for the outcome of the polymerization. In DMSO at weight ratios less than 56% monomer 1 (e.g. 50 and 41%) resulted in lower yields of polymer (52 and 40% respectively). At weight concentrations higher than 60% monomer 1 in DMSO, the polymerisation solution solidified. Likewise in DMF, the weight concentration of monomer was critical for the outcome of the polymerisation reaction, however the maximal yield in DMF was less than in DMSO. A 50% yield of polymer 3 was isolated at monomer 1:DMF weight ratio of 61%. No polymer was isolated when the reaction was conducted at a monomer 1 weight ratio of 33%. At higher monomer weight concentrations (above 75%), the reaction mixture solidified. TABLE 1 Experiment 1:2:CuBr:Bpy a T, ° C. Yield, % {overscore (M)} n {overscore (M)} w /{overscore (M)} n 1  10:1:1:2 100 85 12500 1.17 2  20:1:1:2 80 92 16800 1.15 3  50:1:1:2 100 89 22700 1.20 4 100:1:1:2 100 96 29000 1.14 5 150:1:1:2 110 80 40700 1.13 6 b 100:1:1:2 100 49 23330 1.15 (a) Ratio of initial monomer and initiator concentrations. (b) Reaction stopped after 2.5 minutes by dilution with DMSO and rapid cooling. (B) Polymerisation in THF and Acetone Copper mediated polymerisations of monomer 1 in solvents such as THF, ethyl acetate and acetone also gave narrow MWD polymer 3. Yields ranged from 10-95% depending on the polymer molecular weight. At molecular weights above 10,000 g/mo the yields which was less than that observed when the polymerisation was conducted in DMSO or DMF. The lower yields occured because of premature precipitation of polymer 3. Exemplary copper mediated polymerisations using 0.5 g in monomer 1 were conducted in THF over a 16 h time period at 70° C. The copper chelating ligand used in these THF reactions was N,N,N′,N″,N″-pentamethyidiethylenetriamine (PMDETA). TABLE 2 Experiment 1:2:CuBr:PMDETA a {overscore (M)} n {overscore (M)} w /{overscore (M)} n 1 100:1:1:1.2 14800 1.1 2 200:1:1:1.2  1800 1.12 3 100:1:0.3:1.2 13100 1.09 (a) Ratio of initial monomer and initiator concentrations. Copper mediated polymerisation in acetone gave a 95% yield of polymer 3 when a 1:2:CuBr:Bpy ratio of 55:1:1:2 was used. When this ratio was changed to 100:1:1:2 a 30% yield of polymer 3 was obtained. Example 3 Hydrolysis of the Narrow MWD Homopolymeric Precursor 3 to give Narrow MWD Poly(methacrylic acid) PMAA Sodium Salt 4 Determination of the absolute molecular weight of PMM 4 by GPC-this gives the degree of polymerisation (DP) which can be used to give the absolute molecular weight of the homopolymeric precursor 3 and polymers derived from precursor 3. A sample of the polymeric precursor, poly(methacryloxysuccinimide) 3 (apparent number average molecular weight of 24,800 g/mol; polydispersity index of 1.20; determined by GPC using DMF eluent and PMMA calibration standards) was hydrolyzed to poly(methacrylic acid) (PMM) sodium salt 4 to demonstrate how the precursor 3 can be utilised to prepare narrow MWD PMM sodium salt 4 and to obtain a better indication of the absolute molecular weight of 3. It is critical to obtain knowledge of the absolute molecular weight of the precursor 3 because it is possible then to know the absolute molecular weight of any polymer derived from precursor 3. Poly(methacryloxysuccinimide) 3 (1 g) was dissolved in DMF (5 ml) and aqueous sodium hydroxide (0.66 g, 3 ml H 2 O) was added dropwise causing precipitation of the polymer. The reaction vessel quickly became warm and a homogeneous solution followed. Water (3 ml) was added to the reaction solution and this was then heated at 70° C. for 24 h after which time further water (approx. 50 ml) was added. The solution was dialysed using regenerated cellulose membrane (SpectraPor, MWCO 2000) against water. Lyophilization of the dialysed solution gave a white solid product 4 (0.3 g) which had an infrared spectrum identical with a commercial sample of narrow MWD PMAA sodium salt. The molecular weight of PMAA sodium salt 4 was determined by GPC with phosphate buffer solution at pH 8.5 as eluent and PMAA sodium salt calibration standards. Since GPC calibration standards were the same as PMAA sodium salt 4 isolated by the hydrolysis of the precursor 3, the molecular weight which was obtained was an absolute molecular weight for polymer 4. The absolute number average molecular weight of PMAA 4 for this example was 22,000 with a polydispersity index of 1.20. This value can be used to determine the degree of polymerization (DP) to know the number of repeat units for any polymer derived from 3. Since the repeat unit molecular weight of PMAA sodium salt 4 is 108, the DP for this sample was approximately 203 (i.e. 22,000 g/mol ÷108 g/mol). This means the DP for the precursor 3 is 203, and since the molecular weight of the repeat unit of precursor 3 is 183 g/mol, then the absolute number average molecular weight of precursor 3 in this example was 37,149 g/mol (i.e. 183 g/mol '203). The value of 203 for the DP of precursor 3 can be used in an analogous fashion to determine the absolute molecular weight of polymers derived from 3. Example 4 Conjugation of Amine to Narrow MWD Homopolymeric Precursor 3 to Produce Narrow MWD Polymethacrylamides. Reaction of Precursor 3 with 1-amino-2-propanol to Give Polymethacrylamide 5. To poly(methacryloxysuccinimide) 3 (0.2 g, polydispersity index 1.2, GPC, DMF eluent, PMMA calibration standards) in DMF (3 ml) was added 1-amino-2-propanol (0.16 ml, 2.1 mmol) drop-wise under stirring at 0° C. The solution was allowed to warm to room temperature and then heated to 50° C. for 16 hr. The reaction mixture was cooled to room temperature and slowly added to acetone (20 ml) to precipitate a solid product. The product was further purified by a second precipitation from methanol into 60:40 (v/v) acetone:diethyl ether to give the water soluble polymethacrylamide 5 as a white solid (polydispersity index 1.3; GPC, phosphate buffer eluent, poly(ethylene glycol) calibration standards). The reaction of 1-amino-2-propanol was followed by IR. Shown in FIG. 1 is the are superimposed IR spectra showing the active ester IR band at 1735 cm −1 in narrow MWD homopolymeric precursor 3 which disappears upon the addition of of 1-amino-2-propanol to give polymethacrylamide 5. FIG. 3 shows the GPC elutagramme of the narrow MWD polymethacrylamide 5 as obtained in this example from narrow MWD homopolymeric precursor 3 and is superimposed with the GPC elutagramme for polymethacrylamide 5 which was produced by conventional free radical polymerisation of 6. It is known that polymethacrylamide 5 when prepared from monomer 6 by conventional free radical polymerisation is not cytotoxic. FIG. 4 confirms that narrow MWD polymethacrylamide 5 prepared from precursor 3 is also not cytotoxic. Both polymethacrylamide 5 samples do not display cyctoxicity in this assay compared to polylysine which is used as a cytotoxic control. Dextran is used as a noncytotoxic control. Different amines including diethyl amine, propyl amine, and methyl esters of amino acids have been conjugated to narrow MWD homopolymeric precursor 3 to make homopolymeric narrow MWD polymethacrylamides. It is also possible to effectively conjugate less than an equivalent of the amine to give copolymers like 7 which is shown in FIG. 5 by a corresponding decrease of the IR band for the active ester in the precursor 3 at 1735 cm−1 as a function of the stoichiometry of the added amine (in the example shown below, glycine methyl ester). FIG. 5 shows superimposed IR spectra in the absorbance mode for the sequence of reactions to produce narrow MWD copolymer conjugate 7 derived from the reaction of narrow MWD homopolymeric precursor 3 with the different the stoichiometries that are shown of glycine methyl ester. Actual active ester peak height reductions at 1735 cm −1 were 25.7, 53.7 and 74.7% corresponding to the increasing stoichiometries of 0.25, 0.50 and 0.75 equivalents respectively of glycine methyl ester. This experiment demonstrates the ability to monitor the conjugation of different stoichiometries of amines to narrow MWD homopolymer precursor 3. The experiment below demonstrates the ability to use the narrow the MWD homopolymeric precursor 3 to prepare narrow MWD copolymeric poly(methacrylic acid co methacrylamides) 9. Procedure To an argon purged vial containing the narrow MWD homopolymeric precursor, poly(methacryloxy succinimide) 3 (0.3 g, 1.6 mmol of reactive groups) in DMSO (1 ml) was added 1-amino-2-propanol (In three separate reactions; 0.25 eq, 32 ml, 4.1 mmol; 0.5 eq., 63 ml, 8.2 mmol and 0.75 eq., 95 ml, 12.2 mmol) dropwise under stirring. The vials were then heated at 50° C. for 3 hr and a FT-IR spectrum taken of each reaction solution to confirm that the expected amount of 1-amino-2-propanol was conjugated to precursor 3 to give the copolymeric intermediate 8 (FIG. 6 ). To the reaction solution was then added aqueous NaOH (1.6 ml, 1N). The solution became warm upon addition and soon became less viscous. Hydrolysis was confirmed by the disappearance of the active ester band at 1735 cm −1 by IR spectroscopy. After 5 h of stirring, water (approx. 50 ml) was added and the solution was dialysed using regenerated cellulose membrane (SpectraPor, MWCO 2000) against water. Lyophilization of the dialysed solution gave the narrow MWD copolymeric poly(methacrylic acid co methacrylamides) 9 as white solid products. Mass=0.22 g, 0.23 g and 0.2 g respectively. FIG. 6 shows superimposed IR spectra in the absorbance mode for the sequence of reactions to produce the intermediate narrow MWD copolymer conjugate 8 derived from the reaction of narrow MWD homopolymeric precursor 3 with the different the stoichiometries that are shown of 1-amino-2-propanol. Actual active ester peak height reductions at 1735 cm −1 were 26.0, 52.9 and 76.4% corresponding to the increasing stoichiometries of 0.25, 0.50 and 0.75 equivalents respectively of 1-amino-2-propane. This figure also shows the reduction of the active ester band from the addition of 1 equivalent of 1-amino-2-propanol. The actual reduction was 99.9%. This experiment again demonstrates the ability to monitor the conjugation of different stoichiometries of amines to narrow the MWD homopolymer precursor 3 with the added advantage of being able to chemically functionalise copolymeric intermediates 8 to give functionalised narrow MWD poly(methacrylic acid co methacrylamides) 9. Example 5 Use of Narrow MDW Homopolymeric Precursor 3 to Prepare Water Soluble Copolymeric Conjugates The preparation of water soluble conjugate 12. The letter G in structures 11 and 12 is the conventional single letter abbreviation for glycine. Poly(methacryloxysuccinimide) 3 (100 mg, 0.55 mmol of reactive groups), the model drug derivative, H-Gly-Gly-β-napthylamide HBr0.6H 2 O 10 (19 mg, 0.06 mmol, 0.1 eq., 10% loading) and a magnetic flea were added to a 1.5 ml vial. The vial was sealed with a septum centred screw cap lid and purged with argon for approximately 2 min. DMSO (0.4 ml) was then injected into the vial under argon and the vial was placed onto a magnetic stirrer. Once a solution had formed, a small sample of the solution was removed by syringe under argon for immediate FT-IR spectroscopy. Triethylamine (15.2 ml, 0.11 mmol, 2 salt eq.) was then added under argon to the vial and the vial was placed in an oil bath at 50° C. for 2 h 30 min. After cooling, a sample of the solution was removed from the vial under argon for immediate FT-IR spectroscopy to confirm the addition of 10 by ensuring the corresponding 10% reduction in the active ester peak at 1735 cm −1 had occurred. To the reaction solution containing the copolymer intermediate 11 was added 1-amino-2-propanol (82 mg, 1.1 mmol, 2 eq.) and the solution heated at 50° C. for 1 h 15 min. The water soluble copolymeric conjugate 12 was isolated by precipitation of the DMSO reaction solution into acetone:diethyl ether (50:50 v/v) and further purified by precipitation from methanol into acetone:diethyl ether (50:50 v/v). Shown in FIG. 7 are the superimposed IR spectra to display the changes in the active ester peak during this sequence of reactions to prepare conjugate 12. These 3 IR spectra display the reduction of the height of the active ester band at 1735 cm −1 and the evolution of the amide I and II peaks. Spectrum (A) is the starting precursor 3, spectrum (B) shows the 10% reduction in the height active ester band after addition of 10, and spectrum (C) shows the complete disappearance of the active ester band after the addition of 1-amino-2-propanol to give the narrow MWD copolymeric conjugate 12 with 10% loading of 10. Shown in FIG. 8 are the superimposed IR spectra for the same reaction sequence to prepare conjugate 12. This experiment demonstrated the ability to use the same narrow MWD homopolymeric precursor 3 to prepare conjugates with different loadings of the drug component. In this experiment 0.25 equivalents of amine 10 were used instead of 0.1 equivalents and the peak at 1735 cm −1 displayed a height reduction of approximately 25%. To confirm there was essentially no competing hydrolysis reactions, the intermediate reaction solution was allowed to continue stirring a further 12 hours at 50° C. to ensure no further reduction of the active ester peak occurred. FIG. 8 shows the preparation of narrow MWD conjugate 12 at 25% loading of 10. Spectrum (A) is the starting precursor 3, spectrum (B) shows the 25% reduction in the height active ester band at 1735 cm 31 after addition of 10, spectrum (C) shows there is no further reduction in the height active ester band when the intermediate reaction mixture of 11 was stirred a further 12 h at 50° C. and spectrum (D) shows the complete disappearance of the active ester band after the addition of 1-amino-2-propanol to give the narrow MWD copolymeric conjugate 12 with a 25% loading of 10. The sequence of reactions for example 5 was also carried out using a different amine for the second step. This exemplifies the concept that using the same narrow MWD homopolymeric precursor 3 it is possible to conjugate different property modifying pendent chain molecules to give conjugates that will have different solution properties. The two reaction sequences shown below used aminoethanol and 1-amino-2,3-propane-diol respectively instead of 1-amino-2-propanol for the second conjugation reaction in the sequence. FIGS. 9-10 show the superimposed IR spectra that were obtained to monitor each reaction sequence. FIG. 9 shows the preparation of narrow MWD conjugate 13 at 25% loading of 10. Spectrum (A) is the starting precursor 3, spectrum (B) shows the 25% reduction in the height active ester band after addition of 10, spectrum (C) shows there is no further reduction in the height active ester band at 1735 cm −1 when the intermediate reaction mixture of 11 was stirred a further 12 h at 50° C. and spectrum (D) shows the complete disappearance of the active ester band after the addition of ethanolamine to give the narrow MWD copolymeric conjugate 13 with a 25% loading of 10. FIG. 10 . Preparation of narrow MWD conjugate 14 at 25% loading of 10. Spectrum (A) is the starting precursor 3, spectrum (B) shows the 25% reduction in the height active ester band after addition of 10, spectrum (C) shows there is no further reduction in the height active ester band at 1735 cm −1 when the intermediate reaction mixture of 11 was stirred a further 12 h at 50° C. and spectrum (D) shows the complete disappearance of the active ester band after the addition of ethanolamine to give the narrow MWD copolymeric conjugate 14 with a 25% loading of 10. One experiment with one equivalent of amine 10 (100% loading) to produce narrow MWD conjugate 15 was conducted as a further example to demonstrate that since the narrow MWD homopolymeric precursor 3 has a reactive center on each repeat unit, conjugation of bioactive agents using precursor 3 is efficient. This experiment also demonstrates that the reaction of an amine once 95% incorporation has occurred may have a slower rate because there are relatively few reactive sites remaining. This is why it is important for the conjugation reactions to make narrow MWD, water soluble copolymer conjugates (such as for example 12, 14 and 15) that the second amine be added in excess. The superimposed IR spectra obtained to monitor the reaction to prepare the narrow MWD homopolymeric conjugate 15 are shown in FIG. 11 . FIG. 11 shows the preparation of narrow MWD conjugate 15 at 100% loading of 10. Spectrum (A) is the starting precursor 3, spectrum (B) shows the approximately 95% reduction in the height active ester band after addition of 10 after 1 h, spectra (C, D and E) shows the continued further reduction in the height active ester band at 1735 cm −1 as reaction stirred a total of 2, 3.5 and 4.5 h respectively at 50° C. and spectrum (E) shows the complete disappearance of the active ester band after the reaction mixture stirred a total of 16 h at 50° C. to give the narrow MWD homopolymeric conjugate 15 with a 100% loading of 10. Example 6 Chain Extension Reaction. Synthesis of Poly(methacryloxy succiminde-co-methacryloxy Succinimide) 16. A prerequisite for preparing block copolymers by copper mediated polymerisation is to demonstrate that the dormant chain end groups will initiate a further polymerisation reaction that gives a narrow MWD block without addition of initiator (e.g. 2). Into an argon purged vessel containing copper(I)bromide (4.8 mg, 0.03 mmol), bipyridine (10.4 mg, 0.06 mmol), methacryloxy succinimide 1 (1 g, 5.5 mmol) and poly(methacryloxy succinimide) 3 (0.5 g, number average molecular weight of 33,800 g/mol; polydispersity index 1.15, GPC, DMF eluent, PMMA calibration standards), which had previously been prepared by copper mediated polymerisation, was added DMSO (0.25 g, previously degassed by argon purge). The vessel was stoppered and heated at 130° C. for approximately 10 minutes. After cooling, more DMSO (approx. 7 ml) was added to dissolve the contents which were then slowly added to a solution of acetone to precipitate the block copolymer 16 which was collected and dried in vacuum to give a white solid (1.1 g, 73%). GPC analysis indicated the extension of the starting polymer had occured to give a new second block to produce poly(methacryloxy succiminde-co-methacryloxy succinimide) 16 with a number average molecular weight of 96,500 g/mol with a polydispersity index of 1.1 (DMF eluent, PMMA calibration standards). In separate experiments to probe for possible competing thermal initiation, monomer 1 was stirred alone in DMF at 80 and 110° C. over 8-24 hours. This resulted in the formation of some polymer with a high polydispersity index (>2.5). Example 2 has already established that the copper mediated polymerisation of monomer 1 quickly comes to completion. The reaction (1+3→16) of this example is also appears to be very fast (10 minutes) and gives a narrow MWD block copolymer confirming the presence of dormant chain end group required for polymer block formation. FIG. 12 shows the GPC for narrow MWD poly(methacryloxy succinimide) 3 (Labelled “A ”) that was used as the starting polymer in the chain extension reaction described in example 6. The GPC labelled “B” displays the chain extension reaction to give poly(methacryloxy succiminde-co-methacryloxy succinimide) 16.

A polymer comprising the unit (I) wherein R is selected form the group consisting of hydrogen, C 1 -C 18 alkyl, C 1 -C 18 aralkyl, C 1 -C 18 alkaryl, carboxylic acid, carboxy-C 1-6 alkyl, or any one of the C 1 -C 18 alkyl, C 1 -C 18 alkenyl, C 1 -C 18 aralkyl, C 1 -C 18 alkaryl substituted with a heteroatom within, or attached to, the carbon backbone; R 1 is selected from the group consisting of hydrogen, C 1 -C 6 alkyl groups; X is an acylating agent and wherein the polymer has a polydispersity of less than 1.4, preferably less than 1.2 and a molecular weight (Mw) of less than 100,000, the polymer is preferably made by controlled radical polymerization and is useful in the production of polymer drug conjugates with desirable biological profiles.

REFERENCES TO RELATED APPLICATIONS [0001] This application is a Continuation-in-Part (CIP) of U.S. Ser. No. 08/764,145, filed on Dec. 12, 1996 and on appeal before the Board of Patent Appeals and Interferences, which is a CIP of U.S. Ser. No. 08/407,911, filed on Mar. 21, 1995 and issued as U.S. Pat. No. 5,597,699, which was a CIP of U.S. Ser. No. 08/188,951, filed on Jan. 31, 1994, abandoned, which was a CIP of U.S. Ser. No. 07/954,865, filed on Sep. 30, 1992, abandoned. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] This invention relates generally to drug compositions that optimize or maximize the therapeutic effects of particular receptor-specific agonists, while concurrently preventing or, in the least, significantly ameliorating receptor desensitization, and which derive from the methodology of the inventor's U.S. Pat. No. 5,597,699. More particularly, the instant invention sets forth the methodological improvements, and compositions, that are derived from application of that patent's teachings. These improvements usher in classes of compositions that are pharmaceutically compensated (or fitted) to harmonize with physiologies of diverse therapy recipients. [0004] 2. Discussion of Relevant Art [0005] An agonist is a substance/drug that has affinity for and stimulates physiologic activity at cell receptors that are normally stimulated by naturally occurring substances. As used throughout, an agonist is such a substance/drug that produces a maximal or a nearly maximal response, whereas an antagonist or inhibitor is a substance or molecule that produces no response, but can block the action of the drug-agonist. A partial agonist produces a moderate response and can also block the response of the receptor to the agonist-compound. A competitive antagonist is a substance that competes with the agonist for the receptor, but produces no response. [Note: Hereinafter, the combination of a specific agonist with a suitable antagonist or inhibitor will have one of the identifying forms of notation: agonist-antagonist or agonist/antagonist or antagonist: agonist; in such instances, the dash (-), slash (/) and semicolon (:) connoting the same.] [0006] More than twenty years ago, the idea that beta-adrenergic antagonists could be used to treat heart failure was considered heretical although clinical data were emerging to support this viewpoint (White, D. C., Hata, J. A., Shah, A. S., Glower, D. D., Lefkowitz, R. J., and Koch, W. J., “Preservation of myocardial β-adrenergic receptor signaling delays the development of heart failure after myocardial infarction.” PNAS, 97: 5428-5433 (2000) and references therein). Previously it was thought that failing hearts required positive inotropic support and that the use of beta-antagonists would depress heart function. After more than two decades, the conventional wisdom on this point has been overturned. [0007] In heart failure, there is a biochemical alteration of the β-adrenergic receptor signaling system leading to the loss of cardiac inotropic reserve through β-adrenergic receptor desensitzation. It was demonstrated in a recent study (White, D. C., et al.) that observed desensitization and down-regulation of β-adrenergic receptors, seen in the failing heart, is deleterious for normal heart function (see 2 and references therein). In this study, paraphrasing what the authors wrote: [0008] (1) In a rabbit model of heart failure induced by myocardial infarction, which recapitulates the biochemical β-adrenergic receptor abnormalities seen in human heart failure, delivery of the β-adrenergic receptor kinase ct transgene at the time of myocardial infarction prevents the rise in β-adrenergic receptor kinase 1 activity and expression and thereby maintains β-adrenergic receptor density and signaling at normal levels. Rather than leading to deleterious effects, cardiac function is improved, and the development of heart failure is delayed. These results appear to challenge the notion that dampening of β -adrenergic receptor signaling in the failing heart is protective, and they may lead to novel therapeutic strategies to treat heart disease via inhibition of β-adrenergic receptor kinase 1 and preservation of myocardial β-adrenergic receptor function. [0009] (2) The most promising current therapies in heart failure is the use of β-adrenergic receptor antagonists, which presumably block the chronic activation of the β-adrenergic receptor system by norepinephrine. β-adrenergic receptor kinase 1 up-regulation could be the “first-response” feedback mechanism responding to the enhanced sympathetic nervous system activity because the expression of β-adrenergic receptor kinase 1 in the heart can be stimulated by catecholamine exposure. An opposing hypothesis, however, is that the increase in myocardial G protein-coupled receptor kinase (GRK) activity often observed in the failing heart can mediate changes within the β-adrenergic receptor system that are not protective but that rather take part in the pathogenesis of heart failure. If such is the case, then the inhibition of β-adrenergic receptor kinase 1 might represent a novel therapeutic target in the treatment of the failing heart. [0010] (3) To address specifically the issue of whether β-adrenergic receptor desensitization might have maladaptive rather than adaptive consequences in the setting of heart failure, we have delivered a peptide inhibitor of β-adrenergic receptor kinase 1 activity via in vivo intracoronary adenoviral-mediated gene delivery to the hearts of rabbits that have a surgically induced myocardial infarction (MI). We have shown previously that this model of MI in rabbits results in overt heart failure within 3 weeks, including pleural effusions, ascites, and significant hemodynamic dysfunction. [0011] (4) The conventional view of the role of sympathetic activation in heart failure is that the resultant elevated myocardial β-adrenergic receptor kinase 1 levels and β-adrenergic receptor desensitization in the dysfunctional heart are actually protective mechanisms. Abrogation of such compensatory mechanisms, it has been reasoned, would only worsen the physiologic deterioration caused by excess catecholamine stimulation. Indeed, the chronic use of β-agonists in heart failure is harmful. [0012] (5) First, administration of an oral β-agonist leads to further β-adrenergic receptor down-regulation in the lymphocytes of patients with heart failure. Additionally, the β -adrenergic receptor kinase 1 expression is increased after β-adrenergic receptor stimulation. Therefore, the use of β-agonists in heart failure patients exacerbates disturbances in the myocardial β-adrenergic receptor system, leading to further receptor down-regulation and increases in β-adrenergic receptor kinase 1. In contrast, restoration of β-adrenergic receptor signaling through gene delivery of the β-adrenergic receptor kinase ct has a fundamentally opposite effect at a molecular level, i.e., it preserves the number of β-adrenergic receptors and inhibits β-adrenergic receptor kinase 1. [end paraphrasing] [0013] It is interesting that β-adrenergic receptor kinase 1 inhibition shares with β-blockade the potential to normalize or remodel signaling through the cardiac β-adrenergic receptor system in heart failure. Moreover, both treatments lower cardiac GRK activity, enhance catecholamine sensitivity, and raise or preserve myocardial levels of β-adrenergic receptors (White, et al. and included references). Thus, it is possible that part of the salutary effects of β-blockers on the failing heart is because of their demonstrated ability to reduce expression of β-adrenergic receptor kinase 1 in the heart. With the overwhelming positive data showing the beneficial effects of β-blockers in the treatment of heart failure, it is reasonable to question whether the strategy of adding a β-adrenergic receptor kinase 1 inhibitor adds anything novel to the therapeutic armamentarium. However, given the results of this study, it is apparent that β-antagonist therapy and β -adrenergic receptor kinase 1 inhibition may in fact be complementary therapeutic modalities. [See SUMMARY OF THE INVENTION] [0014] Present theories of receptor activation calculate the response of a receptor as some function of an agonist-receptor complex. There have been several modifications and criticisms of receptor theory (see, for example Keen, M.; Testing Models of agonist for G-Protein Coupled Receptors: Trends Pharmacol. Sci. 12, 371-374, 1991), but none of these treatments examined the discrete change induced by ligand binding to two equilibrium states of a receptor and, consequently, no one has developed the instant (and exacting) method for determining actual drug compositions based upon an optimal ratio of agonist to antagonist which effectively prevent desensitization of cellular receptors that are normally and incipiently responsive to a host of agonists. Careful experimental investigations of several different receptor systems have revealed that receptor theory fails to describe the observed responses in a number of cases. Also, the phenomenon of rapid desensitization has been difficult to model by modem receptor theories. Originally many of these experimental observations were reported in 1957 by del Castillo and Katz in their pioneering work on desensitization (del Castillo, J. and Katz, B. Proc. Roy. Soc. Lond. 146, 369-381, 1957). The present theories are inadequate for at least two fundamental reasons; first, they fail to describe relevant experimental observations, except for limited cases and second, they offer only a “black box” description instead of a physicochemical explanation for receptor response. [0015] In 1991, Geoffrey et al. found that competitive antagonists of a glutamate receptor decreased the desensitization of the receptor (See Geoffrey, M., et al. Molecular Pharmacology 39, 587-591; 1991). They concluded, in this study, that such paradoxical behavior could not be described by the current theories of pharmacologic action deriving from (for example) experimental observations first recorded in 1957 by del Castillo & Katz performing their pioneering work on desensitization. Until most recently, no theory has been able to adequately explain how the behavior observed by Geoffrey et al. occurs; and, the utility of mixing competitive antagonists (or partial agonists) with agonists accurately and, therefore, efficiently to prevent receptor desensitization has been all but overlooked. [0016] Other articles that show the utility (in vivo) of using antagonist/agonist compositions, to prevent receptor desensitization, are extant. One such article is “Antitacyphylactic Effects of Progesterone and Oxytocin on Term Human Myometrial Contractile Activity In Vitro” by Xin Fu, MD, Masoumeh Rezapour, MD, Mats Löfgren, MD, PhD, Ulf ulmsten, MD, PhD, and Torbjörn Bäckström, MD, PhD, all of the Department of Gynecology and Obstetrics, University Hospital, Uppsala, Sweden and published in Obstetrics & Gynecology (1993; 82: 532-8). Therein, Xin Fu et al. conclude that a quantum of an antagonist, progesterone, is observed to reverse the tachyphylaxis (desensitization) to oxytocin (agonist) of human myometrium. A method for quantifying the compounds for this phenomenon is not suggested, particularly for arriving at proper dosages of the antagonist, for consistently achieving the reversal. Nor for that matter, do Xin Fu et al. provide formulas that will maintain a maximal receptor response. [0017] Another disclosure is of certain importance in the quest for in vivo studies to support modeling investigational techniques in drug research: “Beta1 and Beta2 Adrenoceptors in the Human Heart: Properties, Function, and Alterations in Chronic Heart Failure” by Otto-Erich Brödde of Bio-chemisches Forschungslabor, Medizinische Klinik and Poliklinik, Abteilung für Nieren-und Hochdruckkrankheiten, Universitätsklinikum, Essen, Germany. ( Pharmacological Review, 1991, Vol. 43, No. 2). This is a detailed study on chronic heart failure which discusses a recognized utility of using Beta-AR (beta-adrenergic receptor) antagonists for patients in certain types of heart failure (pp. 228-230) and which hypothesizes that such work by occupying Beta-ARs and prevent desensitization of cardiac Beta-ARs (see p. 233 and references therein). [NOTE: No further information is detailed which would inform one of ordinary skill how to quantify the portions of antagonists necessary to fully retard i.e., prevent “down-regulation” (desensitization, ibid p. 233) of Beta-ARs.] [0018] As recently as Jul. 24, 1994, the instant inventor presented his work “A Novel Biophysical Model for Receptor Activation” (R. Lanzara, CUNY, New York and Bio-Balance, Inc., New York, N.Y.) to the XIIth International Congress of Pharmacology at Montréal, Québec, Canada Also presented was a paper published by him concerning Weber's Law (“Weber's Law Modeled by the Mathematical Description of a Beam Balance”, Mathematical Biosciences, 122:89-94 (1994)). These works are included for their teachings on the instant concept, methods of calculation to provide quanta of antagonist: agonist necessary for achieving the objectives of the invention and demonstrate objectively by use of in vivo empirical studies that the invention is a substantial improvement to the prior art and a significant advancement in the field. INCORPORATION BY REFERENCE [0019] The following of the aforementioned works: Geoffroy et al. “Reduction of Desensitization of a Glutamate Ionotropic Receptor by Antagonists” Molecular Pharmacology 39: 587-91 (1991); Xin Fu et al., “Antitachyphylactic Effects of Progesterone and Oxytocin on Term Human Myometrial Contractile Activity In Vitro”, Obstetrics & Gynecology, 82: 532-38 (1993); OttoErich Brodde, “Beta1 and Beta2 Adrenoceptors in the Human Heart: Properties, Function, and Alterations in Chronic Heart Failure”, Pharmocological Review, Vol. 43, No. 2 (1991); Lanzara, R. “A Novel Bio-physical Model for Receptor Activation” Dept. of Allied Health Sci., CUNY, NY, N.Y. and Bio-Balance Inc., NY, N.Y.; and, Lanzara, R. “Weber's Law Modeled by the Mathematical Description of a Beam Balance”, Mathematical Biosciences, 122: 89-94 (1994) are incorporated herein by reference. SUMMARY OF THE INVENTION [0020] The problem is solved for determining the optimal ratio for the concentration of an antagonist- or inhibitor-to-agonist which is sufficient to prevent cellular receptor desensitization, and, without causing unnecessary and unwanted inhibition, maintaining a maximal response. The instant, improved method and formulas describe not only f, the concentration of the antagonist relative to that of the agonist (given by K i , the dissociation constant of the antagonist, divided by φ, the square root of one-half of the product of the two dissociation constants of the drug-agonist for the receptor), but provide a methodology for obtaining the various formulary factors by which I derive the specific ratios of the selected agonist and antagonist for receptor classes among the diverse animal species. When higher ratios of the antagonist are used, more inhibition of the response occurs; and when lower ratios are used, desensitization results. [0021] It is noted that, in the relevant art, there exists a method for calculating drug efficacy by utilization of easily identifiable biophysical parameters. Additional to both in vitro and in vivo data gleaned from the incorporated references (Xin Fu, et al. and Otto-Erich Brodde, ibid.), I initially had performed an in vitro test on Guinea pig trachea, a widely used substitute tissue for pharmacologic research on human trachea, to determine the optimal composition of an antagonist (propranolol) which is mixed with an agonist (isoproterenol) in order to prevent receptor desensitization produced by a large concentration of said agonist (isoproterenol=25 μM). Specifically, the experimental data and the calculated values were compared. The agreement of the experimental data with the calculated value for f=K i /φ was within one and one-quarter percent (1.25%; calculated=0.0395 vs. experimental=0.04). This excellent result validated the method for calculating the optimal ratio of the agonist/antagonist compositions to prevent receptor desensitization. This was a specific test of this invention to determine the optimal ratio of propranolol to isoproterenol in the Guinea pig trachea and proved that there exists a maximally effective ratio that finds utility in its ability to prevent agonist-induced drug desensitization. [0022] The instant method of preventing β-adrenergic receptor desensitization or down-regulation, by creating the optimal ratio of agonist to antagonist combinations, is a complementary therapeutic strategy to what the recent study ( White, D. C. et al., ibid.) suggests as an appropriate therapy to maintain β-adrenergic receptor signaling in patients with heart failure. The difference between our approaches is that while the authors of this study advocate the delivery of an intracellular inhibitor of the β-adrenergic receptor kinase through the “β-adrenergic receptor kinase ct transgene”, I advocate that, by the proper titration of agonist to antagonist, the same beneficial effects will occur. Many of these effects were mentioned by these authors as resulting from both β-blockade therapy and their own “transgene therapy”. The instant teaching is that, because the endogenous levels of catecholamines are usually elevated in patients with heart failure, concomitant use of β-blockers reduces the desensitization of these receptors in these patients with higher than normal norepinephrine or epinephrine levels. This can be more easily understood by observing that in FIG. 2 of my 1997 patent (Lanzara '699, ibid.), the use of any inhibitors (β-blockers) will improve the relative response for the desensitized portion of the curve (to the right of the peak). Therefore, the Lanzara compositions represent the best mode of practice to maintain the β-adrenergic signaling in the failing myocardium. [0023] Having been encouraged by initial successes, I have been able to compound a host of pharmaceuticals that are the scientifically derived optimal ratios, i.e., agonist-antagonist, that work best for the largest population, yet have the least side-effect impact. More to the latter characteristic, I have found, through further empirical studies that, relative to heart therapies, the invention's new compositions presented with significantly less arrhythmias than did agonists alone. A specific composition comprising isoproterenol with metoprolol in the ratio of 1:85, Iso:Met, comprising for a single microgram amount of isoproterenol HCl, 85 micrograms of metoprolol tartrate, is used as a safer and more efficacious alternative to isoproterenol alone. I alter this ratio in a manner normally practiced in the pharmaceutical industry to account for the pharmacokinetic and pharmacodynamic differences between animals and humans and within populations. BRIEF DESCRIPTION OF THE DRAWINGS [0024] Of the drawings: [0025] [0025]FIG. 1 depicts ligand equilibria with the ionic forms of the receptor; [0026] [0026]FIG. 2 is a graphical representation of Relative Response vs. Concentration for Different Concentrations of the Competitive Inhibitor, [I]; [0027] [0027]FIG. 3 reflects curves for the responses as determined by Stephenson; [0028] [0028]FIG. 4 is a model of ΔRH to the operational model and the data of Keen; [0029] [0029]FIG. 5 is the response curves of Dilger and Brett modeled by ΔRH with a diffusion equation; [0030] [0030]FIG. 6 is an experimental dual plot modeling: del Castillo and Katz dose-responses; [0031] [0031]FIG. 7 presents empirical data obtained for in-vitro studies on carbachol-contracted Guinea pig trachea; [0032] [0032]FIG. 8 is a graphical fit of the calculated data (Δ-delta) to the experimental data (dP/dt) for the agonist (isoproterenol), with and without a fixed amount of the antagonist (metoprolol); [0033] [0033]FIG. 9 is a plot of the experimental response in the test animals to the calculated optimal ratio of agonist/antagonist (Iso/Met Combination) derived from the biophysical parameters obtained from fitting the test dosages in FIG. 8 to the equations 6-10; [0034] [0034]FIG. 10 is a graphical comparison of the experimental dP/dt in rats for dobutamine alone (Dob) versus the optimal ratio combination of dobutamine/metoprolol (Dob+Met); [0035] [0035]FIG. 11 is a graphical comparison of the fit of theory (Δ-delta) to the experimental results (dP/dt normalized and Experiment Iso/Met Combination) in vivo. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT [0036] For all of the known receptors, most experimental observations have shown that agonist ligands display two-site binding while antagonist ligands display one-site binding. The experimental observations can be understood as a preferential binding of the agonists for one form of the receptor. This gives rise to the observed two-site binding and the two dissociation constants of the drug for the receptor. This is demonstrated to be a direct consequence of the efficacy of the agonist and is a measure of the response of the system. By this reasoning, antagonists would display equal or nearly equal affinities for each form of the receptor. This is observed as one-site binding and a single dissociation constant for antagonist binding to receptors. For a receptor that exists in two states, an ionizable receptor was selected as a likely example because there is experimental evidence to support this. (See: Davies, A. O. J. Clinical Endocrinology & Metabolism 59, 398-405 (1984); Gende, O. A., Hurtado, M. C. C. & Cingolani, H. E. Acta Physiol. Pharmacol. Latinoam. 35, 205-216 (1985); Hall, M. D., et al. Neurochemical Research 11, 891-912 (1986); Asselin, J., et al. Biochem. J. 216, 11-19 (1983); Barlow, R. B. & Hamilton, J. T. Brit. J. Pharmacol 18, 543-549 (1962); Battaglia, G., Shannon, M., Borgundvaag, B. and Titeler, M. Life Sciences 33, 2011-2016 (1983); and Rocha E. Silva, M. Arch. Int. Pharmacodyn. 128, 355-374 (1960)). [0037] In FIG. 1, the equilibria of the ligand with the ionic forms of the receptor are shown. The two free forms of the receptor (R H and R L ) which can exist in either an ionized (R H ) form or a non-ionized (R L ) form, respectively, react with the drug D, with two different dissociation constants, K DH and D DL ; DR H and DR L are the amounts of the drug-receptor complex in either the high affinity or low affinity forms, respectively. The drug-receptor complex can also exist in either an ionized (DR H ) form or non-ionized (DR L ) form. The non-ionized form is the lower affinity form. This characterization teaches that the protonation of at least one (class of) residue within the receptor alters the affinity of the drug for the two free states of the receptor. The K R term is the dissociation constant of the hydrogen ion (H + ) binding to the receptor in the absence of the drug. The K RD term is the dissociation constant of hydrogen ion (H + ) binding to the receptor in the presence of the drug. [0038] The drug (or ligand) binding to each of the two receptor states can be described by the Langmuir binding expressions: DR H =R H ( D )/(( D )+K DH ) and DR L =R L ( D )/(( D )+ K DL ) [0039] where DR H and DR L are the amounts of the drug-receptor complex for the high and low affinity states, respectively; and, R H and R L are the total amounts of the receptors in the high and low affinity states. The ligand will have a preference for binding to the high affinity receptor state, R H , over the low affinity receptor state, R L , which is a direct result of the different dissociation constants K DH and K DL . Any differences in the affinities of a ligand for the two receptor states produces a “shift” in the receptor reaction quotient similar to Le Chatelier's Principle. [0040] Now introducing a new term, Γ, as a ratio of the high affinity states of the receptor to the low affinity states, the following expression is obtained: Γ=( R H +DR H )/( R L +DR L )  [1] [0041] where Γ is a “weighted ratio” of the two receptor states. By substituting the binding expressions for DR H and DR L the complete expression for Γ can be described as: Γ= R H (1+( D /( D+K DH )))/ R L (1+( D /( D+K DL )))  [2] [0042] The derivation of equation [2] includes the assumption that the concentrations of the free receptor states (R H and R L ) are determined by the environmental influences on the protonation and deprotonation of the receptor and that the drug binding to each state can be described by Langmuir binding. Perhaps the closest physical analogy to elucidate this “weighted ratio” approach is that the receptor equilibrium may be considered analogous to a beam balance with weights. The addition of a ligand is comparable to the addition of weights to each side of the balance relative to a hypothetical affinity with one side having the more weight or “higher affinity”. The weighted ratio would be the ratio of the original weight plus the additional weight on the “high affinity” side of the fulcrum divided by the original weight plus the additional weight on the “low affinity” side. Additionally, a second weighted ratio would be the distances of the centers of mass from the fulcrum. This second weighted ratio would comprise the original distances plus or minus the change in these distances that was necessary to maintain the horizontal equilibrium point. The two weighted ratios will be equivalent and similar to this analysis of the receptor response. Similarly a second or parallel determination of Γ can be made from consideration of the conservation of matter law. This requires that any discrete change or increase (+x) in the high affinity state must be reciprocated by an equal and opposite change (−x) in the low affinity state with all receptor states equal to the total number of receptors (R T ). In this case, the equation for mass balance can be expressed as: R T =( R H +x )+( R L −x )  [3] [0043] Therefore, the weighted ratio of the high to low affinity states can be alternatively expressed as: Γ =( R H +x )/( R L −x )  [4] [0044] and Equation [4] can be solved for the discrete change, x, which yields: x =(Γ R L −R H )/(1+Γ)  [5] [0045] The equivalence of equations [1] and [4] was tested numerically (not shown); also the expression for Γ from equation [1] can be substituted into equation [5] and subsequently into equation [4] to produce the original expression for Γ. Equating the weighted ratios of the high and low affinity receptor states in terms of the ligand binding or the conservation of matter law does not appear to have been done before. Equating the two weighted ratios, equations [2] and [4], and solving for x yields: Δ     RH = R H  R L  ( D )     ( K DL - K DH ) R L  ( 2  D + K DL )     ( D + K DH ) + R H  ( D + K DL )     ( 2  D + K DH ) [ 6 ] [0046] where ΔR H is substituted for x, in order to emphasize that it represents the change in the high affinity state. [0047] Taking the first derivative of the above equation with respect to the dose, D, and setting it equal to zero in order to obtain the peak (maximum) curve yields the following expression for the concentration of the drug where this peak occurs: D =( K DH K DL /2) ½   [7] [0048] In the presence of an antagonist or inhibitor (I), the equilibrium constants, K DH and K DL , will each be multiplied by (K i +[I])/K i so that equation (7) becomes: D =( K DH K DL /2) ½ ( K i +[I] )/ K i   [8] [0049] If the concentration of the inhibitor (I) is expressed as a fraction (f) of the dose of the drug D, i.e., [I] =f[D], then substitution of this expression for [I] into equation (8) and solving for f yields: f=K i ( D −φ)/φ D   [9] [0050] where, φ=( K DH K DL /2) ½ [0051] Observing that equation (9) gives the minimal fractional concentration of the inhibitor with respect to the drug that is necessary to prevent the desensitization of the receptor, it follows that as [D] becomes much larger than φ, equation (9) becomes: f=K i /φ  [10] [0052] This is the fractional dose of the antagonist relative to the concentration of the agonist or drug which is necessary and sufficient to prevent any desensitization of the receptor for the particular drug that is being used. This is refered to as the optimal ratio for any agonist-antagonist composition. [0053] The instant formulation determines the lowest acceptable dose of inhibitor or antagonist to mix with the drug which completely prevents desensitization. It expresses the dose of inhibitor as a fraction of the dose of the drug. Further, the formulation prevents significant inhibition of the response at lower concentrations of the drug, yet prevents any of the desensitization of the receptor which is a direct result of the high concentrations of the drug (see FIG. 2). [0054] Referring particularly to FIG. 2 there is shown a graphical demonstration of the ability of the formulation f D=I to prevent desensitization without affecting the maximum response. Experimentally, computer simulations were carried out to demonstrate the ability of this model, equation [6], to describe a number of dose-response curves that were difficult or impossible to model by previous theories. Previously published experiments were compared to the predictions from this model. As an example, the experimental dose-response curves from del Castillo and Katz were described by equation (6) with and without an inhibitor (see FIG. 6). [0055] Other experimentally determined curves have been described by my method including the more recent work of Keen (Keen, M., Trends Pharmacol. Sci. 12, 371-374 (1991)). The response curves from Keen are given in FIG. 4, wherein the darker curves are the computer generated curves from the model and fit those curves from the experiments and, whereas the lighter curves (generated from the prevalent operational model) failed to fit the experimental curves. Examples follow hereinafter in more detail, illustrative of the experimental development of my invention. EXAMPLE 1 [0056] Stephenson's data (Stephenson, R. P., British. J. Pharmacol. 11, 379-393 (1956)) are presented in FIG. 3. The points on these curves were generated by equation [6]. The value for both of the R H and R L terms was 50 and the values of the pairs of K DH and K DL terms were as follows: Butyl (3×10 −6 , 8×10 −2 ); Hexyl (5×10 −6 , 2×10 −3 ); Ethyl (1×10 −4 , 1×10 1 ); Heptyl (2×10 −5 , 3×10 −4 ); Octyl (3×10 −5 , 2×10 −4 ) ; Nonyl (4×10 −5 , 2×10 −4 ); and Decyl (3×10 −5 , 2×10 −4 ). The concentration of drug [D] is represented on the abscissa in a molar log scale. [0057] The reader will note that equation [6] can represent the experimental data from Stephenson with meaningful biophysical parameters (i.e. the two dissociation constants of the drugs for the two receptor states). EXAMPLE 2 [0058] Referring once again to FIG. 4, the plots of ΔR H (equation [6]−solid lines) for the data of Keen (Keen, 1991) are presented for arecoline, pilocarpine and carbachol as well as the plots of the operational model (broken lines). ΔR H was calculated with 300 as the value for the R H and R L terms to scale the curves appropriately. The K DH and K DL terms were varied in order to model the experimental curves. The K DH and K DL values for arecoline were 2 and 2000 respectively; similarly, the values for pilocarpine were 4 and 220; and the values for carbachol were 0.02 and 1000. [0059] The equation to calculate the curves for the operational model: %     response = α     ( [ R O ] / K AR )     ( D / K A ) 1 + ( 1 + ( [ R O ] / K AR ) )     ( D / K A ) [0060] where ([R O ]/K AR )=16, 7.3, 3.5, 1.3 and 0.116 with α=100% (plotted as the broken lines in the graph). KA is the overall dissociation constant for the binding of the agonist to the receptor as defined in the operational model. [0061] Experimentally determined response curves were examined to test the ability of ΔRH to model these curves. The experimentally determined dose-response curves from Keen (Keen, 1991) and Stephenson (Stephenson, 1956) were easily modeled by ΔRH from equation [6] with appropriately selected K DL and K DH values (FIGS. 3 and 4). Although there may be some tissue dependent effects from unstirred layers or diffusion barriers, no modifications were used in order to model these curves. Other curves were examined to test the ability of equation [6] to model these curves and to determine additional factors that may be necessary to model the total response. [0062] Basically, there were two modifications to ΔRH that were necessary to model the experimental dose-response curves of Dilger and Brett (Dilger, J. P. and Brett, R. S., Biophysical J. 57, 723-731, (1990)) and del Castillo and Katz. The first modification was a diffusion equation to model the time-dependence of the ligand concentration at the receptors and the second modification was a “recruitment function” to model the concentration-dependent “diffusional recruitment” of additional receptors. [0063] Most experimental preparations have multiple diffusion barriers or unstirred layers in the preparations which can cause time-dependent changes in the agonist concentration at the receptor sites. In order to account for this, the following diffusion equation was used: [ D ]     t = ( D )  10 ( t *  Q / r2 ) - ( D ) 10    ( t *  Q / r2 ) [0064] where [D]t is the time-dependent change in agonist concentration. (D) is the applied concentration of the agonist; “t” is the time; “Q” is the diffusion coefficient of the agonist and “r” is the estimated average diffusion distance. With [D]t substituted for (D) in equation [6], a time-dependent response could be modeled. The diffusion expression appears necessary to describe a time-dependence to the experimental curves, but not the overall shapes of these curves. [0065] Because the peak heights of some experimental curves vary with the applied dose of agonist, an additional modification to ΔRH was necessary to model these curves. Application of high agonist concentrations produce large peaks, whereas, lower agonist concentrations produce small peaks in the measured dose-response curves. This is not predicted from plots of ΔRH with or without a diffusion equation. One explanation for this phenomenon is that there is a concentration-dependent “diffusional recruitment” of receptors. Katz and Thesleff (Katz, B. and Thesleff, S., J. Physiol. 138, 63-80 (1957)) and more recently Cachelin and Colquhoun (Cachelin, A. B. and Colquhoun, D., J. Physiol. 415, 159-188, (1989)) suggested that agonists may diffuse to distant receptors in their preparations and they proposed a concentration-dependent change in the total number of receptors as a necessary modification. The receptors which do not participate in the response at low agonist concentration may be either physically distant or separated by diffusion barriers within a particular preparation. This suggests that some of the receptors are removed from the initial site of agonist exposure but become “recruited” as the concentration of the agonist is increased. Because the experimental curves from Dilger and Brett have decreasing peak heights with decreasing agonist concentrations, a “recruitment function” was found necessary to modify ΔRH. This “diffusional recruitment” can be modeled approximately by a hyperbolic function which includes the ligand concentration and an apparent dissociation constant for the half maximal receptor recruitment. R F = R M  ( D ) ( D ) + KF [0066] where R M represents the relative maximum number of receptors and K F is the apparent dissociation constant for the concentration of acetylcholine which produces a half maximum of the peak height. R F adjusted the relative number of receptors contributing to the total response by multiplying ΔRH times R F . EXAMPLE 3 [0067] As depicted in FIG. 5, the response curves of Dilger and Brett are modeled by ΔRH with a diffusion equation, [D]t, to represent the change in concentration with time and a recruitment function, R F , to describe the diffusional recruitment of receptors. The diffusion coefficient used for acetylcholine (ACH) is 6×10−10 m2s−1, which is a generally accepted value. The values for the R H and R L terms are one for this graph. The apparent affinity constant for the diffusional recruitment of receptors, K F , is 20 μM as determined by the half maximal change in the peak heights of the experimental curves. Where “t” is the time in seconds and “900×10-12” is the square of the distance (30×10-6 m). The K DH and K DL values of acetylcholine are 0.01 and 0.1 respectively. [0068] The series of equations to calculate ΔRH are: R F = 100     D / ( D + K F )  [ D ]  t = ( D )  10    ( t *  6 × 10 / 900 × 10 ) - ( D ) 10    ( t *  6 × 10 / 900 × 10 ) DR H = R H  [ D ]  t [ D ]  t + K DH DR L = R L  [ D ]  t [ D ]  t + K DL Γ = R H + DR H R L + DR L Δ     RH = R F  ( Γ     R L - R H ) 1 + Γ [0069] where the last four equations are operationally equivalent to equation [6] for ΔRH. The effect of a competitive inhibitor on the response curves can be modeled by including the expressions for competitive inhibition into the Langmuir binding expressions for DR H and DR L and then substituted into equation [5], so that the weighted ratio becomes: Γ = R H  ( 1 + ( D / ( D + K DH  ( 1 + I / K i ) ) ) ) R L  ( 1 + ( D / ( D + K DL  ( 1 + I / K i ) ) ) ) [0070] where “I/K i ” is the concentration of the inhibitor divided by the dissociation constant of the inhibitor for the receptor. The effect of an antagonist or competitive inhibitor on the response curve shows that when the inhibitor is present the slope of the response curve on the descending side diminishes more than the slope on the ascending side of the curve which is similar to the experimental observations of del Castillo and Katz as well as Geofroy et al. EXAMPLE 4 [0071] [0071]FIG. 6 consists in the two plots of ΔRH which model the experimental dose-response curves of del Castillo and Katz. ΔRH is computed by the series of sequential equations shown below. The values for the R H and R L terms are 100. The initially applied concentration of acetylcholine (ACH) was 100 μM. The values for the maximum peak response of acetylcholine (100 μM) and half maximal peak response (20 μM) were taken from Dilger and Brett for use in the recruitment function, R F . The effective diffusion distance in [D]t is 191 μm and “t” is the time in seconds which is converted to milli-seconds for the plot. The inhibitor concentration for decamethonium, expressed as I/K i is equal to either 0 or 1 ([I]=K i ) for the two plots. The recruitment function, R F , also includes the effect of the competitive inhibitor. Decamethonium, which was a weak partial agonist in the hands of del Castillo and Katz, is treated as a competitive antagonist without any contribution to the response. [0072] The series of equations to calculate ΔRH: R F = 200     ( D ) ( D ) + K F  ( 1 + I / K i )  [ D ]     t = ( D )  10 ( t *  6 × 10 / 364 × 10 ) - D 10 ( t *  6 × 10 / 364 × 10 ) DR H = R H  [ D ]  t [ D ]  t + K DH ( 1 + I / K i DR L = R L  [ D ]  t [ D ]  t + K DL  ( 1 + I / K i ) Γ    = R H + DR H R L + DR L Δ     RH = R F  ( Γ     R L - R H ) 1 + Γ    [0073] To apply the instant methodology to a specific case requiring administration of a drug to a human subject according to a commonly accepted protocol (state of the art), one first obtains the drug's dose-response curve that is provided by the drug's maker or are experimentally determined. The curve is then “fitted” by normalizing for the total number of receptors and optimizing the values for the high and low affinity constants K DH and K DL . These fitted values are the entering biophysical arguments for the calculation of φ and f, according to this specification, which results in the optimal ratio of the antagonist with respect to the drug-agonist (antagonist: agonist) that is necessary to prevent desensitization of the receptor. The administration of antagonist is by normal delivery methods of its own character and may be done during the agonist administration or, if such is autonomic in the recipient, concurrent therewith, or shortly thereafter. Agonists and antagonists are made into pharmaceutical compositions by combinations with appropriate medical carriers or diluents. For example, such mixtures can be dissolved in oils, propylene glycol, physiological saline, isopropyl myristate, ethanol, cremophor, glycol, sesame oil, or other such pharmacological solutions. Formulation as topicals is also available. Pharmacologists familiar with the panoply of drugs and their professional literature may readily use the invention with the guidance herein provided. [0074] As a result of numerous in vivo studies and my biophysical models, several antagonist/agonist pairings of any of the possible combinations of a beta-1-agonist with any of the possible beta-1-antagonists (or partial agonists), in the ratios taught herein, include without limitation: isoproterenol/acebutalol; isoproterenol/atenolol; isoproterenol/labetalol; isoproterenol/metoprolol; isoproterenol/nadolol; isoproterenol/oxprenolol; isoproterenol/pindolol; isoproterenol/propranolol; isoproterenol/sotalol; and isoproterenol/timolol. Similar compositions are made for each of the following beta-1-agonists: adrenaline; dobutamine; epinephrine; ephedrine; metaproteronol; norepinephrine; noradrenaline; and xamoterol, for example: dobutamine/propranolol; dobutamine/atenolol; dobutamine/betaxolol; dobutamine/metoprolol; dobutamine/timolol; dobutamine/sotalol; dobutamine/pindolol; dobutamine/betaxolol; norepinephrine/atenolol ; ephedrine/timolol; epinephrine/sotalol; noradrenaline/pindolol; xamoterol/betaxolol; and metaproteronol/propanolol, to name but a few such beta-1-agonist/antagonist combinations. The invented compositions include all drugs or molecular entities capable of acting as either beta-1-antagonists or beta-1-agonists as the molecular entities to be used in making these compositions; and they also include the use of the enantiomers of the beta-1-antagonists and beta-1-agonists as the working molecular entities. [0075] Initial Experiment [0076] [0076]FIG. 7 provides in vitro experimental data (CEREP, CELLE L=EVESCAULT, France rpt. No. 1124 R 820E), which verify my “optimal ratio method” to determine a specific agonist/antagonist composition to prevent β2 receptor desensitization. The inhibitor constant K i , was first determined for two concentrations of propranolol (1.0 μM and 10.0 μM) measured on the desensitized preparations. The value for K i was 2.96× 10 −7 M. This low value is reasonable because the tissues were treated with 30 μM of the catechol-O-methyl transferase inhibitor U-0521 which was added for forty-five minutes prior to exposure to isoproterenol (the agonist) or propranolol (the antagonist) and present thereafter. This “blunting” of the K i has been previously observed in the presence of metabolic inhibitors. The value of the maximum of the control curve was calculated from a fit of the curve as previously described in this disclosure. This value was calculated from φ=(K DL K DH /2) −½ and found to be 7.48×10 −6 M. It also agreed with a measured estimate from the experimental points. In order to calculate the fraction of inhibitor necessary to prevent receptor desensitization, the following was calculated: f=K i /φ and found to be 3.95×10 −2 which is in excellent agreement with the experimentally determined values of 1.0 μM propranolol/25.0 μM isoproterenol which gives f=0.04. Thus, this experiment confirmed the preparation of an optimal ratio made according to the herein disclosed method. In determining the optimal ratio of propranolol to isoproterenol in order to prevent the isoproterenol-induced desensitization in the Guinea pig isolated trachea, it was noted that other concentrations of propranolol (0.2 and 10.0 μM) that were tested experimentally, were found to be ineffective in restoring the maximum response of the tissue. These results prove valid my initial hypothesis, and later assertion, that there is a maximally effective ratio which will provide the intended results since the concentrations of the propranolol were either smaller or larger than the 1.0 μM found to be optimal for this system. [0077] The conclusions garnered from this specific test show that the invention is logically extendable to include other agonist-antagonist pairs on other receptors which display desensitization or fade. Since propranolol has been labeled as a “negative antagonist” or an “inverse agonist”, those ligands labeled as negative antagonists or inverse agonists would be included in the term “antagonists” within the meaning of this disclosure. Additionally, these compositions can be seen to reverse previously desensitized receptors. The logical extensibility of my invention to include other agonist-antagonist pairs on other receptors and the fact that these compositions can reverse previously desensitized receptors are further militated by a detailed reading of the incorporated references which, although not anticipatory or suggestive of the instant methods and compositions, nonetheless provide data which may be analyzed to infer confirmation of my teachings. [0078] Experiments for Cardiac Desensitization [0079] There was made a fit of the experimental data for the agonist (showing the expected desensitization) with and without the antagonist (at a fixed concentration) to the theory (Δ or ΔRH from equations 1-10. Referring to the first graph, FIG. 8, labeled “Rat Heart”, this was created by fitting the experimental data for the isoproterenol (Iso) alone to the equations 1-10. This was done both with and without a fixed amount of metoprolol (Met) (1 mg/kg/min) to determine the K i for the antagonist, Met. The experimental points for Iso alone are labeled “dP/dt normalized” and the fit based upon theory is labeled “with baseline normalized”. In the presence of the fixed amount of the antagonist, Met, the experimental points are labeled “dP/dt with Met normalized to Iso” and the fit based upon calculation is labeled “fit to Met normalized”. The last curve displayed is the projected curve for the optimal composition which is labeled “with f*[Met]/K i ”. The K DH , K DL and K i were obtained from this fit and put into the final equation for “f” (the fraction of the dose of the antagonist to use with respect to the agonist). From the fit, the values obtained were K DH =19.0; K DL =1.3 and K i =300 micrograms/kg/min. These values were substituted into the equation for f, which yielded 85 to the nearest integer as the optimal ratio. For each microgram amount of isoproterenol, was mixed 85 micrograms of metoprolol and experimentally tested; this is shown in FIG. 9, the graph labeled “Cardiac Response (dP/dt) in Rat”. Therefore, the optimal ratio was 1:85, Iso:Met. This is the ratio which was used to generate the second curve, labeled “Iso/Met Combination”. Summary of the Experiments to Test the Combination of Beta-1-Agonists with Antagonists to Prevent Desensitization [0080] Background [0081] Isoproterenol (Isuprel) and dobutamine are two drugs commonly used today in patients with decreased cardiac output and heart failure. Both are sympathomimetic adrenergic agonists that bind beta-adrenergic receptors and thus promote increased heart rate and contractility. [0082] Metoprolol (Lopressor) is conversely a beta-adrenoreceptor blocking agent that selectively blocks the beta-1-receptors and is frequently prescribed for heart failure. [0083] The time-derivative of the blood pressure in the ventricle of the heart (dP/dT) is an accepted measurement of the contractility of the heart: as the strength of the contractions in the ventricle of the heart goes up, the rate at which the pressure in the ventricle rises will increase. Increased dP/dT therefore implies increased contractility. [0084] Consequently it was proposed that, by infusing an adrenergic agonist in a specific combination with a beta-1-receptor blocker (see U.S. Pat. No. 5,597,699 ('699)) and measuring the resultant left ventricular pressure (LVP) and dP/dT, it would be possible to induce and measure an increased contractility and cardiac output without suffering a corresponding increase in desensitization. [0085] All beta-1-receptor experiments were performed by Gwathmey, Inc. (Boston). [0086] Hypothesis [0087] An undesired side effect that accompanies the use of adrenergic agonists Isoproterenol (Isuprel) and dobutamine is desensitization. In addition, these drugs also produce an increase in heart rate (tachycardia) and arrhythmias. It was proposed that, if these drugs are combined and administered in an optimal ratio as calculated by '699, then the desensitization will be markedly diminished or absent. The agonistic effects of isoproterenol and dobutamine will produce increased contractility with a better therapeutic response; a sustained contractility and possibly reduced arrhythmogenesis with the combination drugs (isoproterenol+metoprolol=Iso+Met or dobutamine+ metoprolol=Dob+Met) than with either drug alone (Iso or Dob). [0088] Methods [0089] Isoproterenol (Iso) and dobutamine (Dob) were tested in vivo with and without the beta-1-antagonist, metoprolol (Lopressor)(Met). [0090] For each of the following experiments, a rat weighing from two hundred to three hundred grams was anesthetized by intraperitoneal (IP) injection of 75-mg/kg sodium pentobarbital (Sodium Nembutal). Following sedation, the neck of the rat was incised and a tracheotomy was performed, inserting a 14-gauge angiocatheter sheath into the trachea of the rat and securing it with a silk tie. The angiocatheter was connected through a small tube to a small animal respirator supplied with 1.0 liters of oxygen per minute and set to 95 breaths per minute. [0091] The right carotid artery was next tied off, and after making a small incision, a Micro-Tip Millar pressure catheter was introduced down through the carotid artery, placing the end of the catheter into the left ventricular cavity of the rat's heart. Position of the catheter tip was determined by the waveform of the pressure reading-placement in the left ventricle was presumed when a diastolic pressure of zero mmHg and a reasonable systolic pressure (70 to 150 mmHg) was observed. Once properly placed, the catheter was secured to the artery with 1-0 silk ties. [0092] Following placement of the Millar catheter, the right jugular vein of the rat was tied off and cannulated by incising the side of the vein and introducing a small (0.3 mm internal diameter), 20 centimeter-long intracatheter pre-loaded with 0.9% saline solution into the vein. Once a reasonable length of the catheter was inserted into the vein, it was tied to the vein with 1-0 silk suture to secure it in place. [0093] The Millar pressure catheter was then connected through a Millar transducer control unit to a digital/analog recording card in a Sonometrics computer. The transmitted Millar pressure signal was then zeroed and calibrated in the Sonometrics SonoLAB data acquisition program. [0094] At this point for each rat, a baseline recording was obtained of the left ventricular pressure tracing. Segments of three to five seconds were recorded, and it was from these recorded tracings that the included figures of maximum left ventricular pressure (reported as LVP), maximum time-derivative of left ventricular pressure (dP/dT), and heart rate (HR) were later determined, by analysis with Sonometrics CardioSOFT data analysis software. [0095] At this point in the experimentation, the procedure followed differed depending upon which drugs and mixtures were being examined, as is described in the following paragraphs. [0096] The IV line was connected to a syringe of isoproterenol (Isuprel) or dobutamine in solution on a fluid infusion pump. The isoproterenol was administered at varying rates (see figures); at each rate the LVP tracing was recorded after several minutes at a constant infusion rate, and the tracing was later analyzed in the same manner as described above for the baseline LVP recordings. The same procedure was then performed in the rats using a solution of metoprolol alone. Again, at each rate, LVP was recorded for later analysis. The procedure was repeated a third time, except that infusion rate of isoproterenol was varied while at the same time a constant dosage of metoprolol (1 mg/kg/min) was administered. This constant dose is not the calculated ratio, but served to calculate an accurate K i for metoprolol in these rats. [0097] In the Iso exposed rats, there were a set of experiments done where the rats served as their own controls. In these experiments the rats were first given Iso alone to either 20 microgram/kg/min dosages or until arrhythmias occurred. They were then allowed to rest and given the Iso+Met combination up to either 20 microgram/kg/min dosages or until arrhythmias occurred. The dP/dt observations were recorded for each infusion. [0098] In rats 1 through 7, dobutamine solution was first infused at varying rates and LVP tracings were recorded. In these experiments, the rats were first infused with a low-concentration solution (for accuracy of administered dosage). After the rate of dobutamine administration had progressed ˜50 to 100 times the initial dosage, the solution was switched to a high-concentration (ten time as concentrated as the low-concentration) solution of dobutamine. This was done to avoid over-loading the rats with too much fluid volume. After completion of the dobutamine infusion in rats 1 through 7, the rats were then infused with a metoprolol solution, at the rates seen in the attached data tables (not shown). LVP was again recorded for later analysis at each infusion rate. [0099] In rats 8 through 11, the rats were infused with the combination solution of dobutamine and metoprolol, in the calculated ratio of 1.0 mg dobutamine to 1.6 mg metoprolol. Infusion rates are displayed in the attached data; LVP tracings were taken at each rate. As was done in the straight dobutamine infusions in rats 1 through 7, the Dob+Met combination was switched from a low-concentration solution to a ten-times more concentrated solution (after the dosage of 100 times the initial dosage), again to avoid over-loading the rat with fluid volume. [0100] Upon completion of each experiment, the rats were euthanized by intravenous (IV) overdose of sodium pentobarbital (75 mg/kg). [0101] Results [0102] Initially, the data obtained from the rats given isoproterenol alone were fit to the theoretical calculations and are presented in FIG. 9. In order to compare these data sets it is routine in pharmacological practice to zero and normalize each set of data to a common baseline so that the data can be compared and analyzed. As can be seen in the graph (FIG. 9: Iso normalized to baseline), with increasing administration of Iso, the dP/dT increased at low dosages, but peaked and rapidly decreased at higher dosages (desensitization), at the same time increasing the number of arrhythmias produced in the heart. The theory fit the experimental data very well with reasonable biophysical parameters (see FIG. 11 in the conclusion). [0103] These experiments performed initially on the rats were done in order to determine the biophysical parameters (KDH, KDL and Ki) for calculating the optimal combination of a beta-1-agonist with antagonist according to the patent, '699. Based on these data, the combination of 1.0 mg isoproterenol with 18 mg metoprolol was calculated, and then tested in rats 5 through 7. Whereas for the dobutamine tests, the combination of 1.0 mg dobutamine with 1.6 mg metoprolol was calculated, and then tested in rats 8 through 11. [0104] Next presented are the data from rats (5-7) tested with the composition Iso+Met in the graph in FIG. 9 titled “Cardiac Response (dP/dt) in the Rat” (Iso/Met combination). When the two were combined, it can be seen that the same increase in dP/dT was observed at low dosages of isoproterenol, but at higher dosages the dP/dT leveled off at an elevated level, rather than decreasing sharply (no desensitization occurred with the combination—Iso+Met). As seen in this graph (FIG. 9), the Iso+Met combination showed a better therapeutic response with a sustained response into the range of concentrations where desensitization would have normally occurred. In addition, there were much less arrhythmias observed in the Iso+Met run than in the Iso alone run. [0105] Next presented are the data from the rats (4-7) treated with dobutamine alone (Dob), in which first dobutamine and then metoprolol alone were administered. Similar to the effects observed with the isoproterenol administration, it can be seen in the graph (FIG. 10: (Dob)) that at low dosages of dobutamine, the dP/dT increased; however at higher dosages the dP/dT again began to decrease (desensitization). With administration of metoprolol alone, there was observed a steadily larger decrease in dP/dT with every increasing dosage administered (not shown). In these seven rats, LVP was also recorded for each rat, and the graphs (not shown) show an effect in LVP parallel to the respective effects in dP/dT with administration of dobutamine or metoprolol alone. Administration of metoprolol alone served as a control to demonstrate that the metoprolol was acting as a β-1 antagonist in these animals. [0106] In rats eight through twelve, the calculated combination of 1.0 mg dobutamine to 1.6 mg metoprolol was administered. Although these rats were given final dosages as high as 8,000 micrograms/kg/min and cumulative dosages estimated to be as high as 70,000 to 90,000 micrograms/kg, they functioned relatively well up until dosages past 1,000 micrograms/kg/min or estimated cumulative dosages of about 10,000 to 20,000 micrograms/kg. At the highest dosages past 1,000 micrograms/kg/min, dP/dt, LVP and heart rate (HR) all declined. [0107] There were several possible reasons for the decrease in heart contractility at these extremely high dosages. First, the toxic level reported for the dobutamine LD50 i.v. in mice is 73 mg/kg (Merck Index p. 3453 (1996)); therefore, the rats were within this range where the toxic effects of dobutamine overwhelm any therapeutic effects and lead to the decline in the viability of the animals. Second, the problem with excessive fluid administration is problematic in these small animals; leading to electrolyte abnormalities and cardiac arrhythmias on the basis of too much fluid within the cardiovascular system. Given these caveats, the data for the Dob+Met rats were taken up to the 1,000 microgram/kg/min dosages and compared to the Dob only rats that were given dosages up to 800 microgram/kg/min. [0108] Taking each set of data zeroing to a baseline and normalizing so that the data can be compared, is routine in pharmacological practice. The normalized averages for each set were compared in FIG. 3 below. For the Dob+Met group it can be seen that the response was maintained throughout the range; whereas, the Dob group showed a decline in response (see FIG. 10). As can be seen in FIG. 10, as the rate of administration of Dob was increased, dP/dT first increased, then peaked, and began to decrease at high dosages (desensitization). A similar effect was observed in the LVP-first an increase, a peak, a slight decrease that leveled off and finally a continued decrease at extremely high dosages. It is important to note however that the peaks in the dP/dT and LVP graphs do not correlate: in fact, the peak in the dP/dT graph came at a point when the LVP levels had returned to baseline. The graph of heart rate versus infusion rate shows that heart rate remained constant until extremely high levels of infusion, at which point the heart rate began to decrease swiftly which could have been due to the toxic effects of the drug at these high dosages. [0109] Conclusions [0110] When considering the raw data representing the isoproterenol tests, one can see that while infusing the combination of Iso+Met may have slightly diminished the absolute action of increasing dP/dT, the percentage change in dP/dT from baseline was largely matched by this mixture. One can also see that while high doses of pure isoproterenol resulted in a decreased dP/dT (desensitization), dP/dT during administration of the combination Iso+Met leveled off at an elevated level (no desensitization) which was sustained into the higher dosages where desensitization would normally occur. This effect suggests promise for the possibility of administering dosages of isoproterenol without having to worry about a dramatic decrease in the contractility of the heart or the potentially fatal increase in cardiac arrhythmias. [0111] From these graphs (see FIGS. 9 and 10), one can see that the combinations Iso+Met or Dob+Met quickly increased dP/dT at low dosages, before stabilizing it at higher dosages. While LVP was first increased at low dosages, it stabilized at baseline levels for the higher dosages. Heart rate remained largely unaffected. These results are exciting in that they suggest that if the right combination of dobutamine and metoprolol is administered, it may indeed be possible to increase dP/dT (i.e. contractility, and thus cardiac output) without affecting the blood pressure or heart rate in the patient. In all, these experiments present exciting prospects for the hope of improving cardiac output without drug desensitization, arrhythmogenesis or tachycardia. [0112] At the higher drug concentrations, there may occur a number of effects that include toxicity; excess fluid administration and electrolyte abnormalities. Although there was no mention made of arrhythmias, these rats appeared to maintain a very high output level over a long time. Although further testing should be done, it appears that these experiments support the hypothesis that desensitization can be reduced or eliminated in the β-1 agonist drugs by combining a β-1 antagonist with the agonist in the proper ratio to allow these drugs to increase contractility of the heart with a better therapeutic response; a more sustainable response and less cardiac arrhythmias. [0113] Finally in considering the ability of the theory from '699 to fit the experimental data, there were essentially three tests of the theory in these experiments. First, the theory was used to fit the initial experimental observations with Iso or Dob alone; Met alone and a fixed amount of Met with Iso or Dob. Second, the biophysical parameters derived from the initial fit (K DH , K DL and K i ) were used to calculate a specific ratio as given in '699. Third, the experiments were conducted with and without the calculated combination and the observations were examined for their fit to the expected values. As seen in FIG. 11, the theory (Δ) fit the experimental data very well. [0114] The administration of antagonist is by normal delivery methods of its own character and may be done during the agonist administration or, if such is autonomic in the recipient, concurrent therewith, or shortly thereafter. It is also well known that agonists and antagonist can be made into pharmaceutical compositions by combinations with appropriate medical carriers or diluents. For example, such mixtures can be dissolved in oils, propylene glycol, physiological saline, isopropyl myristate, ethanol, cremophor, glycol, sesame oil, or other such pharmacological solutions. Formulation as topicals is also available. Pharmacologists familiar with the panoply of drugs and their professional literature may readily use the invention with the guidance herein provided. [0115] This more physiologically subjective (and practical) method, and the compositions derived thereby, constitute effective and significant improvements to my original work. They are commended to the field consistent with the hereinafter appended claims.

Optimal ratios of pharmaceutical compositions of β-1 and β-2 agonists with their respective antagonists. Safer, more cost-effective drugs for heart and lung therapies are made by combining specific antagonists with their agonists to prevent desensitization of cellular receptors, reducing some of the unwanted side-effects of the agonist drugs alone. Determining the optimal concentration of an antagonist or inhibitor, which is necessary to prevent desensitization, without causing unnecessary and unwanted inhibition, creates a new class of pharmaceuticals. To derive an optimum ratio for a specific composition, a formulative method is provided to detail how competitive antagonists of the receptor should be combined with agonists, in specific proportions, to maximize and maintain receptor response throughout drug administration. The “optimal ratio” methodology used to determine a specific agonist/antagonist composition, to prevent β-1 or β-2 receptor desensitization, is experimentally verified and validated for specific compositions. Alteration of a specific ratio is practiced to account for the pharmacokinetic/dynamic differences between animals and humans and within human populations.

BACKGROUND OF THE INVENTION [0001] 1. Technical Field [0002] The present invention—involving bookbinding units that form encased booklets by binding into coversheets inner-leaf sheets that have been collated into bundles—relates to improvements in cover-binding mechanisms for securely binding into booklets inner-leaf sheets having single leaves mixed with saddle-stitch folded sheets. [0003] 2. Description of the Related Art [0004] Bookbinding units that in general collate into bundles sheets that have been printed in a digital printer or other printing machine and encase the bundles in coversheets to form booklets are widely known. With this scheme, inner-leaf sheets collated into a sheet bundle are set into a stack on an inner-leaf tray, and the bundled sheets are conveyed from the tray to an adhesive-application location, and an adhesive (such as a hot-melt adhesive) is applied to a spine-portion endface of the sheets. Meanwhile, a coversheet from a coversheet tray is fed to, and set into place at, a cover-binding location arranged downstream of the adhesive-application location; the spine portion of the inner-leaf sheets, where the adhesive has been applied, is joined to a cover-binding portion of the coversheet in its middle; and thereafter the coversheet is spine-creased and molded in a coversheet pressing means. [0005] Conventionally, as disclosed in Japanese Unexamined Pat. App. Pub. No. 2003-025759, an inner-leaf tray is disposed on one end of the unit, and a cover tray is disposed on the other end. The inner-leaf tray stores collated and stacked inner-leaf sheets (bundles), and the coversheet tray stores a plurality of coversheets of predetermined sizes. The inner-leaf sheets are conveyed in bundle form to a bookbinding processing stage (cover-binding location) situated in the mid-portion of the device, and from the tray the coversheets are conveyed separated into single sheets. To the upstream side of the coversheet binding stage, adhesive tape (or a hot-melt adhesive) is attached to the spine-portion endface of the inner-leaf sheets. In addition, the coversheet binding stage is fitted out with spine-folding press members. Conventional bookbinding units of this sort are known to suffer from the device requiring scaled-up installation space in that, for example, as disclosed in the cited reference, the inner-leaf sheets in bundle form are conveyed with a conveyor mechanism from a sheet supply unit to the bookbinding processing stage. Furthermore, when the three sides (the head, foot and fore-edge portions) of a sheet bundle in booklet form that has been book-forming processed in a bookbinding unit of this sort are trimmed true, the bookbinding unit is equipped with a trimming device that is distinct from the unit, and the trim-finishing is carried out in the trimming device. [0006] Meanwhile, the present applicants have proposed, in Japanese Unexamined Pat. App. Pub. No. 2005-305822 and elsewhere, a unit that continuously bookbinding-processes image-bearing sheets from an image-forming unit. In the publication, a unit is proposed wherein sheets printed with images are collated and stacked in a bookbinding unit connected to a discharge outlet of an image-forming unit. These inner-leaf sheets are conveyed to an adhesive application position by a gripping conveyance means. There a spine portion of the sheet bundle is coated with adhesive. A coversheet is fed from a cover path that is different from the conveyance path for the inner-leaf sheets and set into place in a cover-binding location. [0007] In both of the publications above, the unit collates and stacks simple sheets of the sheet bundle; the unit disclosed in Japanese Unexamined Pat. App. Pub. No. 2003-025759 is configured to set in a feed stacker a sheet bundle composed of simple sheets (a stack of single-leaf sheets). Likewise, the unit disclosed in Japanese Unexamined Pat. App. Pub. No. 2005-305822 collates simple sheets conveyed from the image-forming unit by stacking and storing them in a stacking tray. [0008] The conventional bookbinding unit stacks simple sheets to compose the inner-leaf sheets of the sheet bundle, applies adhesive to the sheet bundle, then joins the sheet bundle to a central spine-binding portion of a coversheet. However, in print-forming inner-leaf sheets in a printing unit or like device, in some cases signatures are created by folding over a plurality of printed sheets. The plurality of sheets is stacked and folded over along the middle, the spine portion is stapled or saddle-stitched to create a signature, and presumably a plurality of signatures is stacked together to be encased in a coversheet as a booklet. [0009] With conventional bookbinding approaches of this sort, prior to forming the text block into a book in the above-described bookbinding unit, it is known to subject the block to a milling process that cuts (grinds) it into a serrated form, and then to set the block into the inner-leaf tray. A problem with in this way finishing into booklets inner-leaf sheets in which sets of sheets have been folded over has been that if the sheets are milling-processed and the adhesive does not penetrate to the inside of the folded sheets, they cannot be securely bound together. BRIEF SUMMARY OF THE INVENTION [0010] There, the inventors determined that binding without trimming is possible by setting the adhesive application amount and temperature (viscosity) when stacking a plurality of folded sheets (quire) and encasing a plurality of them in coversheet. The inventors came upon the idea of varying the adhesive application process, the spine folding process or the trimming process according to the configuration of the inner-leaf sheets to make bookbinding processes possible that conform to a variety of bundle constitutions. [0011] An object of the present invention is to provide a bookbinding unit that securely binds printed or other inner-leaf sheets to a coversheet regardless of whether the inner-leaf sheets are unfolded or include a plurality of folded sheets. [0012] Another object of the present invention is to provide a bookbinding unit that securely binds a variety of sheet bundles to a coversheet with a simple structure by increasing or decreasing the amount of adhesive according to the configuration of the sheet bundle. [0013] It should be understood that in the present invention, “saddle-stitch folded sheets” means a bundle of a plurality of sheets that have been folded onto themselves and bound down the middle. To attain the aforementioned objects, the present invention provides input means for inputting the makeup (constitution) of a bundle of inner-leaf sheets set in a inner-leaf tray, and control means that varies the control of at least one of the means of sheet conveyance means, adhesive application means, and cover binding means to correspond to the bundle makeup from the input means. [0014] The bookbinding unit that encases in a coversheet inner-leaf sheets collated into a bundle has a inner-leaf tray that sets the inner-leaf sheets in bundles and a coversheet tray that sets coversheets and is equipped with a bookbinding path that guides the sheet bundle from the inner-leaf tray to an adhesive application position and a cover-binding location; inner-leaf conveyance means for feeding the sheet bundle from the inner-leaf tray along the bookbinding path; coversheet conveyance means for feeding the coversheet from the coversheet tray to the cover-binding location; adhesive application means disposed in an adhesive application position for applying adhesive to a spine-portion endface of inner-leaf sheets; cover binding means for binding the inner-leaf sheets and coversheet; and control means for controlling the inner-leaf conveyance means, adhesive application means and the cover binding means. The control means has input means for inputting whether the sheet bundle makeup includes saddle-stitch sheets or only simple sheets, and varies the control of at least one of the means of sheet conveyance means, adhesive application means, and cover binding means based on the bundle makeup information from the input means [0015] Trimming means is disposed downstream of the cover binding means to trim true edges of a bound sheet bundle; the control means varies the trimming speed of the trimming means based on the sheet bundle makeup information from the input means. [0016] The control means compares when the input information from the input means includes saddle-stitch sheets and when the sheet bundle includes only simple sheets to (1) slow the conveyance speed of the inner-leaf conveyance means and/or (2) increase the adhesive amount of the adhesive application means, and/or (3) lengthen the adhesive cooling time of the cover binding means, and/or (4) slow down the trimming speed of the trimming means. [0017] The control means controls the trimming means to trim at least the fore-edge of the sheet bundle conveyed from the cover-binding location when the input information from the input means include saddle-stitch sheets. [0018] A first sensor means is disposed in the inner-leaf tray to detect the presence of paper, and a second sensor means is disposed in the coversheet tray to detect presence of the coversheet. The control means controls the inner-leaf conveyance means, adhesive application means, cover binding means, and the trimming means in a preset order when both the first and second sensors detect the presence of paper. [0019] The inner-leaf tray and coversheet tray are disposed so that one is over the other above the bookbinding path. The length of the path from the inner-leaf tray to the cover-binding location is configured to be shorter than the length of the path from the coversheet tray to the cover-binding location. [0020] The present invention has the following effects because the controls of the inner-leaf conveyance means, adhesive application means, and cover binding means are varied according to whether the inner-leaf sheets set in the inner-leaf tray include saddle-stitch sheets. [0021] When the inner-leaf sheets are composed of only simple sheets, or unfolded and saddle-stitch sheets, or only saddle-stitch sheets, the bookbinding processes such as the paper conveyance speed, adhesive application amount, the adhesive cooling time and the trimming speed and the like are varied so the bookbinding process that is appropriate for each type of sheet bundle is possible. [0022] Therefore, while sheet conveyance, the application of adhesive and cooling of the adhesive were performed conventionally in a uniform manner regardless of whether the inner-leaf sheets include saddle-stitch sheets, the present invention solves the problems of missing pages caused by an incomplete gluing and problems in the bookbinding quality where wrinkles or unevenness occur in the spine portion by varying the control conditions of those processes according to the configuration of the sheet bundle. [0023] Furthermore, the present invention has the notable effects of a secure binding, and forming a good quality spine binding without the bundle becoming disorganized in the conveyance process by slowing down the conveyance speed to convey the inner-leaf sheets, increasing the amount of adhesive that is applied and extending the adhesive cooling time. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS [0024] FIG. 1 is an overall view of a bookbinding unit of the present invention; [0025] FIG. 2 is an expanded explanatory view of the bookbinding unit in the unit shown in FIG. 1 ; [0026] FIG. 3 is an explanatory drawing of a configuration of a bundle conveyance means in the unit shown in FIG. 1 ; [0027] FIG. 4 is an overall view of adhesive application means in the unit shown in FIG. 1 ; [0028] FIGS. 5A to 5D are explanatory views of applying adhesive using an adhesive application means shown in FIG. 4 ; FIG. 5A shows an outward movement state of adhesive container; FIG. 5B shows a return movement of the adhesive container; FIG. 5C is a sectional view of FIG. 5A ; FIG. 5D is a sectional view of FIG. 5B ; [0029] FIG. 6 is an explanatory view of a configuration of bundle conveyance means in the unit shown in FIG. 1 ; [0030] FIGS. 7A to 7D are explanatory views of a configuration of a bundle of saddle-stitch sheets in the unit shown in FIG. 1 ; FIG. 7A shows the status of applying adhesive; FIGS. 7B , C, D show the configuration of the sheet bundle; [0031] FIGS. 8A to 8C are explanatory views of operations of coversheet binding procedures in the unit shown in FIG. 2 ; each drawing shows spine folding press members moving between idle positions and folding positions; [0032] FIGS. 9A and 9B are explanatory views of essential portions of the unit shown in FIG. 1 ; FIG. 9A is an explanatory view of a state to set sheets in an inner-leaf tray; FIG. 9B shows a configuration of a first bundle thickness detection means disposed in the inner-leaf tray; [0033] FIG. 10 is an explanatory view of a configuration of sheet width size detection means on the inner-leaf tray and coversheet tray in the unit shown in FIG. 1 ; [0034] FIG. 11 is a block diagram of a configuration of control means in the unit shown in FIG. 2 ; [0035] FIG. 12A is a flowchart showing operating procedures of cover binding means in the unit shown in FIG. 2 ; and [0036] FIG. 12B is a flowchart showing operating procedures of cover binding means in the unit shown in FIG. 2 . DETAILED DESCRIPTION OF THE INVENTION [0037] Preferred embodiments of the present invention will now be explained with reference to the drawings provided. FIG. 1 is an explanatory view of the overall configuration of the bookbinding unit according to the present invention; and FIG. 2 is an expanded view of an essential portion thereof. [0038] The present invention relates to a bookbinding unit A that applies hot-melt adhesive such as glue, or adhesive tape to a spine edge surface of a sheet bundle (inner-leaf sheets) set in a predetermined tray (inner-leaf tray 2 ) and encases the sheet bundle in a coversheet conveyed from a coversheet tray 31 . The bookbinding unit A shown in FIG. 1 is composed of the inner-leaf tray 2 that stores inner-leaf sheets that have been collated into a sheet bundle; adhesive application means 20 that apply adhesive to a spine-portion endface of the sheet bundle conveyed from the tray; coversheet conveyance means 30 that convey to and set a coversheet at the cover-binding location Y; and cover binding means 40 disposed at the cover-binding location. An adhesive application position (hereinafter referred to as the application position) X, a cover-binding location (hereinafter referred to as the binding position) Y, and trimming position Z are disposed in this order in the bookbinding process path (hereinafter referred to as the bookbinding path) 5 . Trimming means 50 that trims true three sides of the sheet bundle covered by the coversheet are disposed in the trimming position Z. The configuration of each of these will now be explained. Inner-Leaf Tray Configuration [0039] The inner-leaf tray 2 disposed in the bookbinding path 5 is composed of a tray that stacks sheets in a bundle; the tray shown in the drawing is substantially horizontally oriented. A trailing edge aligning member 3 that aligns the position of the trailing edge of the sheet and side guides 4 a, 4 b that align the positions of the sheet sides are provided in the inner-leaf tray 2 . It is acceptable for the inner-leaf tray 2 to be fastened to the apparatus frame. However, the drawing shows the tray attached to the apparatus frame to move in up and down directions between a stacking position and a conveyance out position of FIG. 1 . As shown in FIG. 2 , a gear rack 8 established on a bottom portion of the tray 2 is mated to a pinion 9 of a tray elevator motor Ma. The forward and reverse drives of the tray elevator motor Ma raise and lower the inner-leaf tray 2 between the stacking position (solid lines in FIG. 1 ) and the conveyance out position (dashed lines in FIG. 1 ). Therefore, sheets stacked on the inner-leaf tray 2 are lowered in the direction of the arrow a from the stacking position, then are moved in the direction of the arrow b to be transferred to the inner-leaf conveyance means (gripping conveyance means) 10 . Note that the symbol 7 in the drawing denotes an opening cover of the inner-leaf tray 2 ; the cover is openably linked to the apparatus casing by a hinge. Configuration of Inner-Leaf Width Detection Means [0040] The side guides 4 a, 4 b are composed of one or a pair of guide members to align sheets to a side or a center reference. The inner-leaf sheet width size detection means SS 1 is disposed on the side guides 4 a, 4 b shown in the drawing to detect the width size of aligned sheets. The configuration is shown in FIG. 10 . The right side guide 4 a and left side guide 4 b disposed on the top surface of the tray are connected by an interlock gear 4 g to mutually approach and separate from each other the same amount. A flag 4 f is provided on one of the side guides 4 a to detect its position. Positions of the flag 4 f are detected by a plurality of sensor arrays SS 1 to identify the inner-leaf sheet width size. Note that when using a side reference, it is acceptable to align the position of the sheets using one side guide and detect an opposite side edge of sheets aligned to position with this guide directly with a sensor. Configuration of First Bundle Thickness Detection Means [0041] The first sheet bundle thickness detection means St is disposed to detect the thickness of the sheet bundle stacked on the inner-leaf tray 2 . As shown in FIG. 9B , a paper contacting arm 3 a that rises and lowers along a sheet aligning surface of the trailing edge aligning member 3 is supported by a shaft 3 b on a guide member 3 e. The sheet bundle thickness detection means St 1 composed of a position detection sensor (hereinafter referred to as a “Slidac” sensor—Slidac being Toshiba Corp.'s registered trademark for a variable transformer) is provided on the paper contacting arm 3 a. Also, the paper contacting arm 3 a is constantly held at an idle position (the position shown in the drawing) over the tray via a transmission lever 3 d by magnetic force (holding torque) from an elevator motor Mi. Also, when the elevator motor Mi is rotated in a clockwise direction at the sheet conveyance out instruction signal (described below), the paper contacting arm 3 a lowers under its own weight or the force of an urging spring 3 c to the top of an uppermost sheet of paper on the tray. The first sheet bundle thickness detection sensor St 1 detects the position of the paper contacting arm 3 a to detect the thickness of the sheet bundle set on the tray. Tray Sensor Configuration [0042] A first sensor Se 1 is disposed on the inner-leaf tray 2 to detect the presence of sheets. (See FIG. 9B ). The configuration of the sensor is known. For example, it is possible to adopt an empty sensor and the like, so any detailed explanation thereof will be omitted. However, the sensor is composed to detect the existence of sheets on the tray. Configuration of Sheet Conveyance Means [0043] The inner-leaf conveyance means 10 that conveys the sheet bundle from the inner-leaf tray 2 to an downstream application position is composed as shown in FIGS. 2 and 3 . The inner-leaf conveyance means 10 is disposed in the bookbinding path 5 disposed in a longitudinal direction to intersect the device in up and down directions, as shown in FIG. 1 . The sheet bundle received from the inner-leaf tray 2 in a substantially horizontal orientation is turned 90° to become substantially vertically oriented. It is then conveyed to the downstream application position X. For that reason, the inner-leaf conveyance means 10 is composed of a pair of clampers 13 a, 33 b ( 13 a is movable; 13 b is fixed) that grip the sheet bundle, and a unit frame 12 that is equipped with both clampers 13 a, 13 b. Also, this unit frame 12 is rotatably supported on the apparatus frame by the rotating shaft 11 . By rotatingly driving a fan-shaped gear 35 by a turning motor Mb equipped on the apparatus frame, the unit frame 12 turns in clockwise and counterclockwise directions of FIG. 3 around the rotating shaft 11 . [0044] As described above, the movable clamper 13 a and fixed clamper 13 b are risibly attached to the unit frame 12 rotatably supported on the apparatus frame. A movable frame 16 matingly supported by the guide rail (rod) 16 a (partially shown in FIG. 3 ) is provided on the unit frame 12 . The pinion 17 P connected to an elevator motor Mc provided on the unit frame 12 and the gear rack 17 R provided on the movable frame 16 are meshed. Therefore, the movable frame 16 is raised and lowered by the elevator motor Mc, and can convey sheets downstream along the bookbinding path 5 . [0045] The movable and fixed clampers 13 a, 13 b are mounted on the movable frame 16 . The fixed side clamper 13 b is fastened to the left and right side frames that compose the movable frame 16 with a width size to grip sheets; a rod 18 is disposed on the movable side clamper 13 a, the rod 18 matingly supported by the bearing 14 provided on the movable frame 16 . A pinion of the grip motor Md is meshingly linked to the gear rack 18 R integrally formed on the rod 18 . [0046] Therefore, the movable clamper 13 a approaches the fixed clamper 13 b with the grip motor Md thereby nipping (gripping) sheets with the fixed clamper 13 b. Conversely, when the movable clamper 13 a separates from the fixed clamper 13 b in an opposite direction, the nipping of the sheets is released (the grip on the sheets is freed). In this way, the clampers 13 a, 13 b are caused to grip the sheet bundle by the grip motor Md. The turning motor Mb changes the orientation of the sheet bundle from a horizontal orientation to a vertical orientation, then the elevator motor Mc moves the vertically oriented sheet bundle to the downstream application position X along the bookbinding path P 5 . Note that Sg in the drawing denotes the grip end sensor. The grip end sensor is disposed on the movable clamper 13 a to detect whether the sheet bundle has been securely gripped with the predetermined pressure. Configuration of Second Bundle Thickness Detection Means [0047] The second sheet bundle thickness detection means St 2 is disposed on the movable flapper 13 a to detect the thickness of the gripped sheet bundle. The movable clamper 13 a is caused to approach the fixed clamper 13 b as described above by the grip motor Md to grip the sheet bundle. This gripping action is detected by the grip end sensor Sg. This sensor detects the thickness of the sheet bundle being gripped when it detects the position of the movable clamper 13 a when the detection signal is issued. The sheets at this time are firmly compressed by an urging spring, not shown, so a highly precise detection of the sheet bundle thickness is possible. For that reason, the Slidac sensor that detects the position is disposed along with a bearing 14 on the rod integrated to the movable clamper 13 a. This sensor composes the second sheet bundle thickness detection means St 2 . [0048] The sheet bundle thickness information detected by the second sheet bundle thickness detection means St 2 (1) sets the gap between the adhesive applicator roll, described below, and the sheet bundle according to the thickness of the sheet bundle; (2) adjusts the setting position of the coversheet and the amount it is fed to correspond to the thickness of the sheet bundle so that the sheet bundle matches the center of the coversheet; (3) adjusts the starting position (idle position) of the spine folding press means, described below, to correspond to the sheet bundle thickness; and (4) adjusts the starting position (idle position) of the trimming means, described below, to correspond to the sheet bundle thickness. That information is used in finishing processes. Configuration of Adhesive Application Means [0049] Adhesive application means 20 is composed of an adhesive container 21 that holds an adhesive, such as glue and the like; an applicator roller 22 rotatably installed in the container; a drive motor Me that rotatingly drives the applicator roller 22 ; and a drive motor Mf that reciprocates the adhesive container 21 along the sheet bundle. FIG. 4 is a conceptual view of the adhesive application means. The adhesive container 21 is formed to a shorter length (dimension) than the bottom side edge of the sheet bundle (the spine portion covered at the binding process). This is supported on a guide rail 24 (see FIG. 4 ) of the apparatus frame to move along the bottom side edge of the sheet bundle along with the applicator roller 22 installed in that container. The adhesive container 21 is connected to a timing belt 23 installed on the apparatus frame; a drive motor Mf is connected to the timing belt 23 . [0050] The adhesive container 21 shown in the drawings is configured to move along the sheet bundle, but it is also acceptable to adopt a tray shape that is longer than the length of the sheet bundle, and to move only the applicator roller 22 in the left and right directions of the drawing. Note that the applicator roller 22 shown in the drawing is composed of a porous and heat resistant material and is configured to be impregnated with adhesive. This enable adhesive to form layer on the circumference of the applicator roller. [0051] The drive motor MF reciprocates the adhesive container 21 between a home position HP and a return position RP where the return operation is started along the sheet bundle, and to a refilling position where adhesive can be charged to the container. Each position is set to the positional relationships shown in FIG. 4 ; the return position RP is set based on sheet width size information. The adhesive container 21 is set to the home position HP when the power is turned on (at device initialization). For example, this moves from the home position HP to the return position RP after a predetermined amount of time (estimated time for the sheet bundle to reach the adhesive application position) after a sheet grip signal of the grip end sensor Sg of the inner-leaf conveyance means 10 . At the same time as this movement, the drive motor Me starts rotating the applicator roller 22 . Note that Sp in the drawings denotes the home position sensor of the adhesive container 21 . [0052] With the rotation of the drive motor Mf, the adhesive container 21 starts moving from the left side of FIG. 4 to the right side along the guide rail 24 . The amount of travel of the inner-leaf conveyance means 10 is adjusted by the elevator motor so that the applicator roller 22 pressingly contacts the sheet bundle to slightly separate the edges of the sheets (see FIGS. 5A and 5C ) in the advancing path, and forms a predetermined gap Ga with the sheet bundle edge in the return path (to return from the return position RP to the home position HP) to apply adhesive (see FIGS. 5B and 5D ). The adjustment of the amount of adhesive using the amount of travel of the sheet bundle is based on the sheet bundle thickness information from the second sheet bundle thickness detection means St 2 . If the sheet bundle is thick, the gap Ga is widened to increase the amount of adhesive applied. If the thickness is small, the gap Ga is narrowed to reduce the amount of adhesive applied. Instead of controlling the elevator motor Mc of the inner-leaf conveyance means 10 to adjust the amount of travel of the sheet bundle, it is also acceptable to equip roller position adjusting means that adjust the up/down position of the applicator roller 22 . When the drive motor Mf moves the adhesive container from the operating position where adhesive is applied to the sheet bundle to the idle position EP separated therefrom at the idle instruction signal, adhesive can be recharged from an adhesive tank 25 disposed in the idle position EP. [0053] The unit shown in FIG. 1 has a feature to set the gap Ga based on the “bundle makeup” information of the inner-leaf sheets, described below, at the same time as the sheet bundle thickness information from the second sheet bundle thickness detection means St 2 , when setting the gap Ga. The bundle composition of the inner-leaf sheets is input using a control device B, described below. Input selections can be either “composed of only simple sheets in the state shown in FIG. 7B (hereinafter referred to as simple sheets),” “composed of simple sheets and saddle-stitch sheets in the state shown in FIG. 7D (hereinafter referred to as mixed sheets),” or “composed only of saddle-stitch sheets in the state shown in FIG. 7C (hereinafter referred to as folded sheets).” Here, the gap Ga is set so that the standard gap Ga 1 for simple sheets, and the non-standard gap Ga 2 for mixed sheets or folded sheets have a relationship of Ga 2 >Ga 1 . (See FIG. 7A ) Note that in this case, the differences in gaps are determined by experiment for the properties of the adhesive being used. Coversheet Feeder Unit [0054] The sheet bundle applied with adhesive at the adhesive application means 20 is bound to the coversheet, but the feeding of the coversheet will now be explained. The coversheet feeder unit B disposed over the bookbinding unit A is composed of one or a plurality of coversheet stacking trays 31 for stacking sheets (a drawing shows two tiers of stacking trays), pickup means 32 for separating sheets on the coversheet stacking tray 31 into single sheets, and a coversheet feeding path 6 for guiding a sheet from the pickup means 32 to the binding position Y. [0055] Special sheets such as thick or coated sheets are prepared as coversheets in the coversheet tray 31 . A sheet on the stacking tray is conveyed to the coversheet conveyance path 6 at a control signal sent from the bookmaking unit A. The reason why there is a two-tiered approach to the coversheet stacking trays 31 is that it is possible to prepare different types of coversheets on the trays in advance, so the operator can select the type of coversheet to bind to the sheet bundle from the selected stacker. Configurations of Coversheet Conveyance Path [0056] The configuration of the coversheet conveyance path 6 will now be explained with reference to FIG. 2 . The coversheet conveyance path 6 conveys and sets a coversheet from the coversheet tray 31 to the binding position Y established at the intersection of the bookbinding path 5 . Particularly, a feature of the unit shown in the drawing is that the length of the coversheet conveyance path 6 , in other words the length of the path from the coversheet tray 31 to the binding position Y (L 1 , not shown) and the length of the path from the inner-leaf tray 2 of the bookbinding path 5 to the binding position Y (L 2 ; not shown) are set to a relationship of L 1 >L 2 . To make the unit more compact, the inner-leaf tray 2 and coversheet tray 31 are arranged one above the other, and the length (L 1 ) of the path of the coversheet tray is longer than the length (L 2 ) of the path of the inner-leaf tray 2 . This makes a more compact unit possible that conveys a coversheet requiring twice the length of the inner-leaf sheets to the binding position Y. [0057] The conveyance roller that conveys the coversheet and an aligning mechanism 35 are disposed in the coversheet conveyance path 6 . A path guide that forms the coversheet conveyance path 6 is composed of movable guides 36 a, 36 b that move up and down between a guiding orientation and a retreated orientation upstream and downstream of the binding position Y. (See FIG. 2 ) This guide is positioned in the guiding orientation (see the state shown in FIG. 3 ) to guide the coversheet to the binding position Y, and is shifted to the retreated orientation (not shown) when the coversheet is being folded. [0058] The aligning mechanism 35 is composed of nipping claw 35 a that engages a trailing edge of the coversheet, an aligning member 35 b that offsets in a direction perpendicular to the direction of conveyance the coversheet gripped by the nipping claw 35 a, and a forward and reverse drive roller 35 r that switches back the coversheet conveyed in the coversheet conveyance path 6 to abut the nipping claw 35 a, provided in the coversheet conveyance path 6 . The forward and reverse drive roller 35 r is composed to move up and down with regard to its retreated idle position above the coversheet. [0059] Therefore, the coversheet conveyed into the coversheet conveyance path 6 is switched back and conveyed by the reverse drive of the forward and reverse drive roller 35 r at a predetermined timing after its trailing edge passes the aligning mechanism 35 . Then, the trailing edge of the sheet abuts the nipping claw 35 a which corrects any skewing of the sheet. In this state the nipping claw 35 a grips the trailing edge of the sheet and the aligning member 35 b equipped with this nipping claw 35 a moves in a direction perpendicular to the direction of sheet conveyance to align the sides of the sheet. This corrects any skewing the coversheet may have in the leading and trailing edge directions of sheet conveyance, and the position of the sheet in its width direction (a direction perpendicular to the direction of sheet conveyance) (in other words correction of the side edge positions). The coversheet that has been aligned is conveyed toward the downstream binding position Y by the forward and reverse drive roller 35 r. Conveying and setting the sheet at the binding position Y is performed by the coversheet conveyance means (roller) 30 conveying the coversheet from the aligning position a predetermined amount. Configuration of Coversheet Size Detection Means [0060] In the same way as the inner-leaf tray 2 , a second sensor Se 2 that detects the presence of sheets on the tray and coversheet width size detection means SS 2 that detects the width of the sheets on the tray are disposed in the coversheet tray 31 . The second sensor Se 2 has the same configuration as that in the inner-leaf tray 2 explained with reference to FIG. 9 , and the detection means SS 2 has the same configuration as that in the inner-leaf tray 2 explained with reference to FIG. 10 ; both sensors are disposed in the coversheet tray 31 . [0061] A coversheet length size detection sensor SS 3 that detects a trailing edge of the conveyed coversheet is disposed in the coversheet conveyance path 6 . The length of the sheet is calculated using the time from when this sensor detects the leading edge of the coversheet to the time it detects the trailing edge of the coversheet and the sheet conveyance speed. Configuration of Cover Binding Means [0062] Adhesive is applied by the adhesive application means 20 to the bottom edge of the sheet bundle gripped by the inner-leaf conveyance means 10 at the sheet bundle conveyance path P 5 , and the adhesive container 21 is then retracted to its home position HP outside of the path. The inner-leaf conveyance means 10 moves the sheet bundle along the bookbinding path 5 from the application position X to the binding position Y. At the same time, a coversheet is conveyed to the binding position Y and set at the coversheet conveyance path 6 . Cover binding means 40 is provided at the binding position Y. This cover binding means 40 is composed of a spine rest plate 41 and spine-folding press members 42 . Configuration of Spine Rest Plate [0063] As shown in FIG. 6 , the shutter vane-shaped spine rest plate 41 that intersects the bookbinding path 5 is disposed in the binding position Y. This spine rest plate 41 is disposed directly under (at the downstream side) the spine-folding press members 42 a, 42 b at the binding position Y of the bookbinding path 5 . These spine-folding press members 42 a, 42 b cooperate to fold the coversheet. The spine rest plate is configured to move between an operating position positioned in the bookbinding path 5 , and is configured to be advanced and retreated by drive means (such as a solenoid and the like), not shown. Also, the spine rest plate 41 is formed by a metal plate with high coefficient of thermal conductivity and good heat dissipation effect, and can cool the adhesive (hot-melt adhesive is shown in the drawing) applied to the sheet bundle. Control of Spine Press Members [0064] The control of the spine press members 42 a, 42 b will now be explained. The spine press members 42 a, 42 b are controlled to be positioned at the spine folding position (see FIG. 8A ) when a coversheet is fed from the coversheet conveyance path 6 to the binding position Y, and to be positioned at their home positions (see FIG. 8B ) retracted from the bookbinding path 5 when the sheet bundle and coversheet from the bookbinding path 5 are being joined. Next, the spine press members 42 a, 42 b fold the coversheet in the process of moving from their home positions to the spine folding positions ( FIG. 8C ). A transmission mechanism such as a drive motor, and rack and pinion are installed on the left and right spine press members 42 a, 42 b. Configuration of Bundle Posture-Reorienting Means [0065] The following will now explain the finishing process for the sheet bundle formed into a booklet. The finishing process trims true three side edges of the sheet bundle in booklet form excluding the spine portion. Folding rollers 45 are disposed downstream of the cover binding means 40 . Further downstream, a bundle-posture reorienting means 46 that turns the sheet bundle over from top to bottom, and trimming means 50 that trims true the edges of the sheet bundle are disposed in the trimming position Z positioned further downstream. The bundle posture changing means 46 turns the covered sheet bundle fed from the binding position Y to a predetermined direction (or orientation) and conveys the sheet bundle to the downstream trimming means 50 or to the storage stacker 57 . The trimming means 50 trims the fringes of the sheet bundle to align the edges. Therefore, the bundle posture changing means 46 is equipped with swivel tables 47 a, 64 b that grip and turn the sheet bundle fed from the folding rollers 45 . As shown in FIG. 1 , the swivel tables 47 a, 47 b are furnished on the unit frame 48 installed on the apparatus frame to rise and lower. The pair of swivel tables 47 a, 47 b that sandwich the bookbinding path 5 are rotatably supported on bearings in the unit frame 48 ; one of the movable swivel tables 47 b is supported to move in a sheet bundle thickness direction (a direction orthogonal to the bookbinding path 5 ). Spinning motors, not shown, are furnished in the bookbinding path for the swivel tables 47 a, 47 b to change the posture (or orientation) of the sheet bundle. Configuration of Trimming Means [0066] Trimming means 50 are provided downstream of the bundle posture changing means 46 . As shown in FIG. 1 , the trimming means 50 is composed of a trimming edge pressing member 52 that pressingly supports the edge of the sheet bundle to be trimmed against a blade-edge bearing member 51 , and a trimming blade unit 53 . The trimming edge pressing member 52 is disposed in a position that opposes the blade-edge bearing member 51 disposed in the bookbinding path 5 , and is composed of a pressing member that is moved in a direction that is perpendicular to the sheet bundle by drive means, not shown. The trimming blade unit 53 is composed of a flat, blade-shaped trimming blade 54 and a cutter motor Mh that drives that blade. The trimming means 50 with this configuration cuts a predetermined amount around the edges, excluding the spine of the sheet bundle that has been made into a booklet, to align the edges. [0067] A discharge roller 55 and storage stacker 57 are disposed downstream of the trimming position Z. This storage stacker 57 stores sheet bundles in an inverted manner as shown in FIG. 1 . This storage stacker 57 is disposed to be drawn from the unit as shown in FIG. 1 . The stacker can be drawn toward the front side of the apparatus (the front side of the sheet in FIG. 1 ). The operator can view it from the top direction when it is drawn to the front of the unit. Configuration of Control Means [0068] The following will now explain the control of the bookbinding unit A shown in FIG. 1 . FIG. 11 is a block diagram shown a configuration of the controls. The control is composed of a bookbinding control unit 65 furnished in the bookbinding unit A, and a controller 60 . The controller 60 in the drawing is composed of a computer device. As shown in the drawing, the controller 60 is composed of an input means 61 , display unit 62 and control CPU 60 P; the bookbinding control unit 65 is composed of a control CPU 65 P built-in to the bookbinding unit A. [0069] The controller 60 performs the role of input means 61 for inputting processing conditions when binding a booklet, a memory means for storing inputted data, and the function of the display means 62 for displaying a jam or other states of the bookbinding process. Note that the controller 60 can also be integrated to the bookbinding control unit 65 . [0070] Particularly, the “size of the saddle-stitch sheets,” “coversheet size,” and “inner-leaf sheet bundle makeup” are input with the unit shown in the drawing. This information is used as the control conditions for the bookbinding processes described below. Also, although not shown, it is possible to add functions to the controller 60 . For example, a layout function that adjusts the coversheet setting position so that the title formed on the spine of the coversheet is positioned in the center, or a function for setting the bookbinding process such as adjusting the amount of adhesive that is applied to the sheet bundle according to the properties of the adhesive being used can be added for the aspects of the bookbinding process. When using a computer as the controller 60 , it is simple to add these functions or create programs to correct them. [0071] A ROM 75 that stores a program for executing the bookbinding operation, and a RAM 76 that stores data that sets the control conditions are connected to the bookbinding control unit 65 . The bookbinding control unit 65 is composed of the unit starting control unit 65 a, the inner-leaf conveyance control unit 65 b, the coversheet conveyance control unit 65 c, the adhesive application control unit 65 d, the coversheet binding process control unit 65 e, the trimming process control unit 65 f, and the stack control unit 65 g. [0072] An appropriate size determining means 66 is incorporated in the bookbinding control unit 65 for determining whether the size of sheets prepared in the inner-leaf tray 2 and the coversheet tray 31 are capable of performing the predetermined bookbinding operation. This means is composed of a primary determining means 66 a for determining the size using the sheet width size, and a secondary determining means 66 b for determining the size using the sheet length. The primary determining means 66 a is incorporated in the unit starting control unit 65 a. [0073] The unit starting control unit 65 a is equipped with a first sensor Se 1 disposed in the inner-leaf tray 2 ; a sheet presence determining means 67 for determining whether saddle-stitch sheets and coversheet have been set in the trays using signals from a second sensor Se 2 disposed in the coversheet tray 31 ; primary determining means 66 a of the appropriate size determining means; and the tray sheet bundle thickness comparison means 68 . Data 76 a of the maximum sheet bundle thickness that can be gripped by the inner-leaf conveyance means 10 is provided from the RAM 76 to the comparison means 68 . [0074] The unit starting control unit 65 a configured as described above is configured to determine whether sheets have been set in the inner-leaf tray 2 and coversheet tray 31 , whether the widths of the sheets match, and whether the thickness of the sheet bundle set in the inner-leaf tray 2 exceeds the maximum permissible thickness of a sheet bundle. [0075] The inner-leaf conveyance control unit 65 b controls the inner-leaf conveyance means 10 . If predetermined conditions are met at the unit starting control unit 65 a, the inner-leaf conveyance means 10 is started to convey inner-leaf sheets from the inner-leaf tray 2 into the unit. For that reason, the speed setting data 76 b to be set based on the “bundle makeup information” from the input means 61 is received from RAM 76 to set the speed to convey the inner-leaf sheets. The second sheet bundle thickness detection means St 2 detects the thickness of the sheet bundle gripped by the inner-leaf conveyance means 10 and that thickness information is stored in an internal memory. [0076] The coversheet conveyance control unit 65 c starts the pick-up means disposed in the coversheet tray 31 and feeds one sheet from the tray at a time. The coversheet length detection means SS 3 disposed in the coversheet conveyance path 6 detects the length of the coversheet. The secondary determining means is provided to determine whether the length of the coversheet is able to perform the predetermined bookbinding process, based on the value of that detection. Operation data 76 c that calculates a length of the bookbinding process is supplied from the RAM 76 in the control unit. Also, a conveyance amount operation means (not shown) is provided in the coversheet conveyance control unit 65 c for positioning the coversheet in the binding position Y based on the sheet bundle thickness detected by the second sheet bundle thickness detection means St 2 . [0077] The adhesive application control unit 65 d is composed of an adhesive amount setting means and temperature setting means. Adhesive amount setting data 76 d and adhesive temperature control data 76 e are provided from RAM 76 . Particularly, the adhesive amount setting means sets the adhesive amount based on bundle makeup information of the inner-leaf sheets, and sheet bundle thickness information detected by second bundle thickness detection means. This is configured to adjust the coating gap Ga between an edge of the sheet bundle in the inner-leaf conveyance means 10 and applicator roller according to that setting. [0078] This coversheet binding control unit 65 e controls the spine rest plate 41 and spine-folding press members 42 a, 42 b. That control is configured to execute the operations explained with reference to FIG. 8 . Cooling time setting data 76 f for cooling adhesive is supplied from RAM 76 when the coversheet binding control unit 65 e touches the spine covering portion against the spine rest plate 41 after the binding process. This cooling time setting data selects one of a plurality of data based on the inner-leaf sheet thickness configuration information. [0079] The trimming process control unit 65 f is composed of operation means that calculates the trimming amount using the trimming blade 54 , speed setting means for setting the trimming speed of the trimming blade 54 and stroke setting means for setting the movement stroke of the trimming blade 54 . Also, the trimming amount operation means is configured to calculate the trimming about using inner-leaf sheet size information, coversheet size information, and sheet bundle thickness information detected by the second sheet bundle thickness detection means St 2 . The speed setting means is configured to set the cutting speed using the inner-leaf sheet bundle makeup information. The stroke setting means sets the trimming starting position (the idle position) of the trimming blade using sheet bundle thickness information. [0080] The stack control unit 65 g controls the discharge roller 55 and is configured to store sheet bundles conveyed from the bookbinding path 5 in the storage stacker. Explanation of Bookbinding Operation [0081] The bookbinding procedures in the unit shown in FIG. 1 will now be explained with reference to the flowchart shown in FIG. 12 . The unit shown in FIG. 1 is configured to perform the following bookbinding operations using the bookbinding control unit 65 disposed in the bookbinding unit A and the controller 60 disposed in the computer device connected to the bookbinding control unit 65 . Initial Operations [0082] First, the bookbinding control unit 65 executes an initialization operation when the unit power is turned ON. (St 01 ). When the unit power is turned ON, the control unit composed of the control CPU 65 P detects whether there are any sheets remaining in the bookbinding path 5 and coversheet conveyance path 6 . If there is a sheet existing in either of the paths, the control CPU 65 P issues a “jam” warning. Along with this, the adhesive application means 20 , the cover binding means 30 and the trimming means 50 are set to their initial states (home positions). Sheet-Setting Operation [0083] Next, the controller 60 detects whether there is a sheet in the inner-leaf tray 2 and coversheet tray 31 . The first and second sensors Se 1 and Se 2 disposed in each tray detect (determine) whether there are sheets (St 02 ). When both sensor means Se 1 and sensor means Se 2 are ON, the system waits for sheets to be prepared in the trays and when both are ON, the system shifts to the next step. Size Information Input [0084] The controller 60 then prompts for input of the coversheet size information, inner-leaf sheet size information and inner-leaf sheet bundle makeup information from the input device (means) 61 . That information can be selected or directly input via a computer. In such a case, sensors can be provided in each tray to detect sheet sizes using inner-leaf sheet size information and coversheet size information. However, the drawing shows only the inner-leaf sheet width size detection means SS 1 disposed to detect the size of the inner-leaf sheet, and the coversheet width size detection means SS 2 that detects the size of the coversheet is positioned in the coversheet tray 31 ; the coversheet length size detection means SS 3 that detects the length of the sheet is disposed in the coversheet conveyance path 6 . The system is configured to make a primary determination of whether the inner-leaf sheets and coversheet can perform the predetermined bookbinding operation using the width size information, and then a secondary determination using the coversheet length information. Sheet-Bundle-Makeup Information Input [0085] Further, for “inner-leaf sheet bundle makeup information” a user is prompted to input, using the input means 61 of the controller 60 , the structural makeup of a bundle of inner-leaf sheets set on the inner-leaf tray 2 . The user inputs whether the inner-leaf sheets collated into a sheet bundle are: constituted from simple sheets only (“simple-sheet makeup” hereinafter), constituted from simple sheets and saddle-stitch folded sheets (“mixed-sheet makeup” hereinafter), or constituted from saddle-stitch folded sheets only (“folded-sheet makeup” hereinafter). This bundle makeup information is used to set the control conditions, described below, of the bookbinding process that follows. Suitable Size Primary Determination [0086] The controller 60 performs the primary determination of whether the predetermined bookbinding process is possible with each sheet using a conforming sheet determination means 66 a based on detection results from the inner-leaf sheet width detection means SS 1 disposed in the inner-leaf tray 2 and the coversheet width detection means SS 3 disposed in the coversheet tray 31 . (Step St 04 ) Determining whether the inner-leaf sheet width and coversheet width (the length in the top to bottom direction after the bookbinding process) match determines whether the predetermined bookbinding process is possible. Also, the bookbinding control unit 65 prohibits shifting to the later processes (St 05 ) when both sheet widths do not match, and issues a “size mis-match” warning to the operator at the same time. If the operator inputs in instruction to “continue process with unmatched sizes,” this is cleared and the system shifts to the next step. Operation of First Bundle Thickness Detection Means [0087] Next, the controller 60 issues an “inner-leaf conveyance out” command to convey out the inner-leaf sheet set in the inner-leaf tray 2 toward the inner-leaf conveyance means 10 . When this command is received (when sizes match in the primary determination), the bookbinding control unit 65 detects the thickness of the inner-leaf sheet bundle set in the inner-leaf tray 2 . This is detected using the first sheet bundle thickness detection means St 1 disposed in the inner-leaf tray 2 . (First sheet bundle thickness detection; St 05 ) This sheet bundle thickness is canceled by rotating the paper contacting arm 3 a held magnetically at its initial position (the uppermost position) in advance with the rotation of the elevator motor Mi. The paper contacting arm 3 a is lowered by an urging spring 3 c to touch the uppermost sheet on the tray. At this time, the position of the paper contacting arm detects the sheet bundle thickness by detection using the Slidac sensor. [0088] The controller 60 determines whether the sheet bundle can be conveyed based on detection values for the first sheet bundle thickness detection means St 1 . (St 06 ) The detection value and the preset maximum permissible sheet bundle thickness of the inner-leaf conveyance means 10 are compared for this determination. The controller 60 then determines whether the detection value exceeds the maximum permissible sheet bundle thickness. When it is determined that the maximum permissible sheet bundle thickness has been exceeded, the saddle-stitch sheet conveyance out is prohibited. The controller 60 warns the operator by displaying on a display unit that the maximum sheet bundle thickness permissible for bookbinding has been reached. Operations for Conveying Out Inner-Leaf Sheets [0089] When the number of inner-leaf sheets is determined to be less than the maximum permissible sheet bundle thickness in the first sheet bundle thickness determination, the bookbinding control unit 65 hands the inner-leaf sheets to the downstream inner-leaf conveyance means 10 . For that reason, the unit in the drawing lowers the inner-leaf tray 2 from the setting position to the conveyance out position. After the tray is lowered, the inner-leaf conveyance means 10 grips the sheet bundle on the tray using the fixed clamper 13 b and the movable clamper 13 a. A sheet feeding means, not shown, is installed in the inner-leaf tray 2 . This pushes the sheet bundle along the tray to the inner-leaf conveyance means 10 . The sheet bundle on the tray is conveyed out to the downstream inner-leaf conveyance means 10 (St 07 ). Second Sheet-Bundle Thickness Detection [0090] The inner-leaf conveyance means 10 that transfers the inner-leaf sheets as described above changes the orientation of the sheet bundle simultaneous to the sheet bundle thickness being detected. The inner-leaf conveyance means 10 nips the sheet bundle between the fixed clamper 13 b and movable clamper 13 a with a strong pressure. The second sheet bundle thickness detection sensor St 2 and gripping sensor Sg are provided on the movable clamper 13 a; the second sheet bundle thickness detection means St 2 detects the sheet bundle thickness. (St 08 ) These detection values are used to set control conditions such as the amount of adhesive to apply using the adhesive application means 20 , the coversheet setting position of the coversheet conveyance means 30 , the idle position of the cover binding means 40 , and the trimming blade idle position of the trimming means 50 and the like. Changing Bundle Orientation [0091] At the same time as the second sheet bundle thickness detection, the bookbinding control unit 65 receives the gripping end signal from the gripping end sensor Sg, then rotatingly drives the turning motor Mb to turn the sheet bundle substantially 90°. Then, the inner-leaf sheets handed over in a horizontal orientation from the inner-leaf tray 2 are turned substantially vertically to be conveyed along the bookbinding path 5 which is also vertically oriented. Setting Application Position of Inner-Leaf Sheets [0092] The bookbinding control unit 65 conveys the inner-leaf sheets and sets them at a predetermined adhesive application position using the elevator motor Mc of the inner-leaf conveyance means 10 . (St 09 ). At that time, the bookbinding control unit 65 varies the speed to convey the inner-leaf sheets to the application position X using the inner-leaf conveyance means 10 according to the bundle makeup information. For that purpose, the bookbinding control unit 65 , in an instance of a “mixed-sheet makeup” or a “folded-sheet makeup” that includes saddle-stitch folded sheets, compares the instance with the case of a “simple-sheet makeup” and sets the speed of the elevator motor Mc for the inner-leaf conveyance means 10 to a lower rate. [0093] Next, the bookbinding control unit 65 is equipped with inner-leaf sheet setting position operation means that calculate a setting position of the inner-leaf sheets based on the bundle makeup information and the bundle thickness information. As described above, the inner-leaf sheet setting position operation means sets the inner-leaf sheets at the adhesive application position so that the adhesive application amount is standard when the bundle makeup of the inner-leaf sheets is (1) configured of simple sheets, and so that the application amount is greater compared to the standard amount when the bundle makeup of the inner-leaf sheets is (2) configured of mixed sheets or folded sheets. At the same time as this, this sets the inner-leaf sheets at the adhesive application position to increase or decrease the amount of adhesive to apply according to the bundle thickness detected by the second bundle thickness detection means St 2 . (St 09 ) [0094] For that reason, the inner-leaf conveyance means 10 adjusts the gap Ga (see FIG. 6 ) between the applicator roller 21 and edges of the sheets disposed in the adhesive application position when using the elevator motor Mc to set the inner-leaf sheets at the application position X. This position adjustment is achieved by the varying the amount of rotation of the elevator motor Mc. However, operation means are configured to calculate the amount of rotation using the bundle makeup information and sheet bundle thickness information. A data table that sets the amount of motor rotation according to the inner-leaf sheet bundle thickness for the operation means is provided on RAM 76 . Rotation amounts are set in this table to correspond to bundle thickness with standard and non-standard. Compared to standard, the adhesive application amount is greater for non-standard. The differences in the adhesive application amounts for standard and non-standard are determined by testing according to the adhesive properties and application temperature (viscosity). When the inner-leaf sheet bundle makeup only has simple sheets, the adhesive application amount is set to standard. For the other sheet bundle constitutions, the adhesive application amount is set to non-standard. Coversheet Conveyance [0095] Next, almost in tandem to setting the sheet bundle at the adhesive application position, the bookbinding control unit 65 conveys the coversheet from the coversheet tray 31 to the cover-binding location Y. (St 10 ) For that reason, the bookbinding control unit 65 rotatingly drives the pickup means 32 of the coversheet tray 31 at a signal from the gripping end sensor Sg of the inner-leaf conveyance means 10 , for example, to separate coversheets into single sheets. The coversheet is fed to the coversheet conveyance path 6 and to the aligning mechanism 35 . The coversheet size that reaches the aligning mechanism 35 is detected by the coversheet length detection means SS 3 . In other words, the sensor detects the leading and trailing edge of the coversheet conveyed through the coversheet conveyance path 6 . The time for the sheet to pass therethrough is used to calculate the length of the sheet in its direction of conveyance to detect the length of the coversheet. Suitable Size Secondary Determination [0096] The controller 60 recognizes the length of the coversheet using the detection signal from the length detection means of the coversheet, and determines whether the coversheet is twice the length of the coversheet input using the input means 61 (St 11 ). In other words, the controller 60 determines whether the length of the coversheet conforms to the predetermined bookbinding process. The controller 60 prohibits application of adhesive by the adhesive application means 20 and processes a jam when the length is determined to be non-conforming at the secondary determination. [0097] The jam process is either for the operator to remove the non-conforming coversheet that is in the coversheet conveyance path 6 , or to convey it out of the unit from an ejection outlet (discharge outlet). Also, the inner-leaf sheets are conveyed out from the bookbinding path 5 to the stacker 57 by the inner-leaf conveyance means 10 . At this time can be bound (top binding) by adhesive to prevent the sheet bundle from becoming in disarray. [0000] Setting Coversheet into Binding Location [0098] At the determination above, when the coversheet size conforms to the bookbinding process, the bookbinding control unit 65 controls a coversheet conveyance roller 30 to convey the coversheet from the aligning mechanism 35 and sets it at the cover-binding location Y. (St 12 ) The positioning of the coversheet at the cover-binding location is set so that the coversheet spine binding portion is positioned at the reference position shown in FIG. 8 , considering the bundle thickness detected by the second bundle thickness detection means St 2 . In other words, the coversheet is fed to the cover-binding location Y so that the fore-edge of the coversheet is aligned after the spine is bound, according to the thickness of the sheet bundle. Adhesive Application Operation [0099] The bookbinding control unit 65 receives the signal that the coversheet is set at the cover-binding location Y, and coats the spine portion of the sheet bundle set at the adhesive application position with adhesive at step St 09 . (St 13 ) The adhesive application is executed by the adhesive application means 20 reciprocating the adhesive container 21 along an edge of the sheet bundle. In other words, with the outward movement of the adhesive container 21 , the edge of the sheet bundle is caused to separate (the states of FIGS. 5A and 5C ) and applies adhesive in the return movement ( FIGS. 5B and 5D ). Coversheet Binding Operation [0100] Next, the bookbinding control unit 65 the inner-leaf sheets in the inner-leaf conveyance means 10 to the cover-binding location Y and touches the sheet bundle to the preset spine binding portion of the coversheet in an upside-down T shape. The coversheet at this time is supported by the spine rest plate 41 and the spine-folding press members 42 retreat from the spine folding position. In this way, after abutting and joining the inner-leaf sheets to the coversheet, the bookbinding control unit 65 moves the spine-folding press members 42 to the spine folding position. The amount of movement of the spine-folding press members is set according to the sheet bundle thickness detected by the second sheet bundle thickness detection means St 2 . The coversheet is bound to the sheet bundle at this cover-binding location Y. (St 14 ) Adhesive Cooling [0101] After the coversheet is bound to the sheet bundle, the bookbinding control unit 65 waits for a predetermined cooling time to pass while pressing the coversheet against the spine rest plate 41 . (St 15 ) When the cooling time has passed, the adhesive (hot-melt adhesive) coated on the spine portion of the inner-leaf sheets hardens and forms the spine portion of the booklet. The bookbinding control unit 65 is configured to set the cooling time according to the sheet bundle makeup information. In other words, depending on the bundle makeup, the adhesive application amount is set to a standard cooling time when the sheet bundle is standard or when it is non-standard, it is set to a non-standard cooling time, the latter, non-standard cooling time set to be longer than the standard cooling time. Trimming [0102] After the cooling time has passed, the bookbinding control unit 65 feeds the sheet bundle encased in the coversheet to the downstream folding rollers 45 where they fold the coversheet to completely fold the coversheet. The trimming means 50 is disposed downstream of the folding rollers 45 . At the trimming position Z, the trimming means trims true three sides of the sheet bundle, excluding the spine portion. (St 16 ) The swivel tables 47 a, 47 b change the orientation of the sheet bundle so that the trimming means 50 can trip the top, bottom and fore-edge portions in that order. At this time, the bookbinding control unit 65 changes the speed of the movement of the trimming blade 54 based on the bundle makeup information of the inner-leaf sheets. In other words, if the sheet bundle is composed of simple sheets the speed is high, and if the sheet bundle is composed of folded sheets, the speed is low. Stacking Storage Operation [0103] The bookbinding control unit 65 feeds the sheet bundle to the discharge roller when the trimming process is completed and stores the sheet bundle in the stacker 57 . (St 17 ) [0104] As described above, the present invention is equipped with a controller 60 and bookbinding control unit 65 to vary the adhesive application amount using the adhesive application means, the adhesive cooling amount using the cover binding means, and/or the trimming speed using the trimming means according to when the bundle makeup of the sheet bundle set on the inner tray is (1) composed only of simple sheets, (2) composed of a mix of saddle-stitch and simple sheets, and (3) composed of only saddle-stitch sheets. [0105] For that reason, the control conditions are set so that the adhesive application amount is greater for (2) and (3) that include saddle-stitch sheets, the adhesive cooling time is longer and the trimming speed is slower. Only the outermost sheet of saddle-stitch sheets that have been folded over each other is coated with adhesive and bound, and a gap (gap d in FIGS. 7C and D) is formed at the spine portion between separate sheet bundles. However, the adhesive impregnates this gap portion and hardens the folded sheet bundle to bind them to the coversheet. At the same time as this, there is no wrinkling or unevenness caused by the gap d (because of the adhesive filing the gaps) when the spine portion is folded and pressed. [0106] Also, by lengthening the cooling time setting when the sheet bundle makeup includes saddle-stitch sheets, there is no worry of adhesive leaking out when trimming the sheet bundle later, and by slowing down the trimming speed, trimming can be performed without wear on the trimming blade. [0107] The present application claims priority from Japanese Pat. App. No. 2007-244303, which is herein incorporated by reference.

Bookbinding unit enabling, in encasing inner-leaf sheets in coversheets to form booklets, secure book-forming binding regardless of whether the inner-leaf sheets constitute a simple-sheet bundle or are made up of a plurality of folded-over signature sheets. Constituent components are: inner-leaf sheet tray; coversheet tray; bookbinding process path for guiding sheets from the inner-leaf sheet tray to successive adhesive-application and cover-binding locations; inner-leaf conveyor; coversheet conveyor for conveying coversheets to the cover-binding location; bundle-spine adhesive applicator in the adhesive-application location; and cover binder in the cover-binding location. Components' controller is configured to receive input as to whether inner-sheet-bundle makeup includes saddle-stitch sheets or is of simple sheets only, and, based on the bundle makeup information, varies its control of at least one of the coversheet conveyor, adhesive applicator, and cover binder.

CLAIM OF PRIORITY UNDER 35 U.SC. §119 [0001] The present Application for Patent claims priority to Provisional Application No. 60/830,735 entitled “METHOD AND APPARATUS FOR CONTINUOUS ASSESSMENT OF A CARDIOVASCULAR PARAMETER USING THE ARTERIAL, PULSE PRESSURE PROPAGATION TIME AND WAVEFORM,” filed Jul. 13, 2006, and assigned to the assignee hereof and hereby expressly incorporated by reference herein. FIELD OF THE INVENTION [0002] The invention relates generally to a system and method for hemodynamic monitoring. More particularly, the invention relates to a system and method for estimation of at least one cardiovascular parameter, such as vascular tone, arterial compliance or resistance, stroke volume (SV), cardiac output (CO), etc., of an individual using a measurement of an arterial pulse pressure propagation time and a waveform. DESCRIPTION OF THE RELATED ART [0003] Cardiac output (CO) is an important indicator not only for diagnosis of disease, but also for continuous monitoring of the condition of both human and animal subjects, including patients. Few hospitals are therefore without some form of conventional equipment to monitor cardiac output. [0004] One way to measure CO is using the wellknown formula: [0000] CO=IER*SV,   (Equation 1) [0000] where SV represents the stroke volume and HR represents the heart rate. The SV is typically measured in liters and the HR is typically measured in beats per minute, although other units of volume and time may be used. Equation 1 expresses that the amount of blood the heart pumps out over a unit of time (such as a minute) is equal to the amount it pumps out on every beat (stroke) times the number of beats per time unit. [0005] Since the HR is easy to measure using a wide variety of instruments, the calculation of CO usually depends on some technique for estimating the SV. Conversely, any method that directly yields a value for CO can be used to determine the SV by dividing by the HR. Estimates of CO or SV can then be used to estimate, or contribute to estimating, any parameter that can be derived from either of these values. [0006] One invasive method to determine CO (or equivalently SV) is to mount a flow-measuring device on a catheter, and then to thread the catheter into the subject and to maneuver it so that the device is in or near the subject's heart. Some such flow-measuring devices inject either a bolus of material or energy (usually heat) at an upstream position, such as in the right atrium, and determine flow based on the characteristics of the injected material or energy at a downstream position, such as in the pulmonary artery. Patents that disclose implementations of such invasive techniques (in particular, thermodilution) include: [0007] U.S. Pat. No. 4,236,527 (Newbower et al., 2 Dec. 1980); [0008] U.S. Pat. No. 4,507,974 (Yelderman, 2 Apr. 1985); [0009] U.S. Pat. No. 5,146,414 (McKown et al., 8 Sep. 1992); and [0010] U.S. Pat. No. 5,687,733 (McKown et al., 18 Nov. 1997). [0011] Still other invasive devices are based on the known Fick technique, according to which CO is calculated as a function of oxygenation of arterial and mixed venous blood. In most cases, oxygenation is sensed using right-heart catheterization. There have, however, also been proposals for systems that non-invasively measure arterial and venous oxygenation, in particular, using multiple wavelengths of light; but to date they have not been accurate enough to allow for satisfactory CO measurements on actual patients. [0012] Invasive methods have obvious disadvantages. One such disadvantage is that the catheterization of the heart is potentially dangerous, especially considering that the subjects (especially intensive care patients) on which it is performed are often already in the hospital because of some actually or potentially serious condition. Invasive methods also have less obvious disadvantages. One such disadvantage is that thermo-dilution relies on assumptions such as uniform dispersion of the injected heat that affects the accuracy of the measurements depending on how well they are fulfilled. Moreover, the introduction of an instrument into the blood flow may affect the value (for example, flow rate) that the instrument measures. Therefore, there has been a long-standing need for a method of determining CO that is both non-invasive (or at least as minimally invasive as possible) and accurate. [0013] One blood characteristic that has proven particularly promising for accurately determining CO less invasively or non-invasively is blood pressure. Most known blood pressure based systems rely on the pulse contour method (PCM), which calculates an estimate of CO from characteristics of the beat-to-beat arterial pressure waveform. In the PCM, “Windkessel” (German for “air chamber”) parameters (characteristic impedance of the aorta, compliance, and total peripheral resistance) are used to construct a linear or non-linear hemodynamic model of the aorta. In essence, blood flow is analogized to a flow of electrical current in a circuit in which an impedance is in series with a parallel-connected resistance and capacitance (compliance). [0014] The three required parameters of the model are usually determined either empirically, through a complex calibration process, or from compiled “anthropometric” data, that is, data about the age, sex, height, weight, etc., of other patients or test subjects, U.S. Pat. No. 5,400,793 (Wesseling, 28 Mar. 1995) and U.S. Pat. No. 5,535,753 (Petrucelli et al., 16 Jul. 1996) are representative of systems that utilize a Windkessel circuit model to determine CO. [0015] Many extensions to the simple two-element Windkessel model have been proposed in hopes of better accuracy. One such extension was developed by the Swiss physiologists Broemser and Ranke in their 1930 article “Ueber die Messung des Schlagvolumens des Herzens auf unblutigem Wegf,” Zeitung für Biologie 90 (1930) 467-507. In essence, the Broemser model—also known as a three-element Windkessel model-adds a third element to the basic two-element Windkessel model to simulate resistance to blood flow due to the aortic or pulmonary valve. [0016] PCM systems can monitor CO more or less continuously, without the need for a catheter to be left in the patient. Indeed, some PCM systems operate using blood pressure measurements taken using a finger cuff. One drawback of PCM systems, however, is that they are no more accurate than the rather simple, three-parameter model from which they are derived; in general, a model of a much higher order would be needed to accurately account for other phenomena, such as the complex pattern of pressure wave reflections due to multiple impedance mismatches caused by, for example, arterial branching. Other improvements have therefore been proposed, with varying degrees of complexity. [0017] The “Method and Apparatus for Measuring Cardiac Output” disclosed by Salvatore Romano in U.S. Pat. No. 6,758,822, for example, represents a different attempt to improve upon PCM methods by estimating the SV, either invasively or non-invasively, as a function of the ratio between the area under the entire pressure curve and a linear combination of various components of impedance. In attempting to account for pressure reflections, the Romano system relies not only on accurate estimates of inherently noisy derivatives of the pressure function, but also on a series of empirically determined, numerical adjustments to a mean pressure value. [0018] At the core of several methods for estimating CO is an expression of the form: [0000] CO=HR* ( K*SV est )  (Equation 2) [0000] where HR is the heart rate, SV est is the estimated stroke volume, and K is a scaling factor related to arterial compliance. Romano and Petrucelli, for example, rely on this expression, as do the apparatuses disclosed in U.S. Pat. No. 6,071,244 (Band et al., 6 Jun. 2000) and U.S. Pat. No. 6,348,038 (Band et al., 19 Feb. 2002). [0019] Another expression often used to determines CO is: [0000] CO=MAP*C/tau   (Equation 3) [0000] where MAP is mean arterial pressure, tau is an exponential pressure decay constant, and C, like K, is a scaling factor related to arterial compliance K. U.S. Pat. No. 6,485,431 (Campbell, 26 Nov. 2002) discloses an apparatus that uses such an expression. [0020] The accuracy of these methods may depend on how the scaling factors K and C are determined. In other words, an accurate estimate of compliance (or of some other value functionally related to compliance) may be required. For example, Langwouters (“The Static Elastic Properties of 45 Human Thoracic and 20 Abdominal Aortas in vitro and the Parameters of a New Model,” J. Biomechanics, Vol. 17, No. 6, pp. 425-435, 1984) discusses the measurement of vascular compliance per unit length in human aortas and relates it to a patient's age and sex. An aortic length is determined to be proportional to a patient's weight and height. A nomogram, based on this patient information, is then derived and used in conjunction with information derived from an arterial pressure waveform to improve an estimate of the compliance factor. [0021] It is likely that the different prior art apparatuses identified above, each suffer from one or more drawbacks. The Band apparatus, for example, requires an external calibration using an independent measure of CO to determine a vascular impedance-related factor that is then used in CO calculations. U.S. Pat. No. 6,315,735 (Joeken et al., 13 Nov. 2001) describes another device with the same shortcoming. [0022] Wesseling (U.S. Pat. No. 5,400,793, 28 Mar. 1995) attempts to determine a vascular compliance-related factor from anthropocentric data such as a patienit's height, weight, sex, age, etc. This method relies on a relationship that is determined from human nominal measurements and may not apply robustly to a wide range of patients. [0023] Romano attempts to determine a vascular impedance-related factor solely from features of the arterial pressure waveform, and thus fails to take advantage of known relationships between patient characteristics and compliance. In other words, by freeing his system of a need for anthropometric data, Romano also loses the information contained in such data. Moreover, Romano bases several intermediate calculations oil values of the derivatives of the pressure waveform. As is well known, however, such estimates of derivatives are inherently noisy. Romano's method has, consequently, been unreliable. [0024] What is needed is a system and method for more accurately and robustly estimating cardiovascular parameters such as arterial compliance (K or C) or resistance, vascular tone, tau, or values computed from these parameters, such as the SV and the CO. [0025] One of the present inventors earlier published that the SV can be approximated as being proportional to the standard deviation of the arterial pressure waveform P(t), or of some other signal that itself is proportional to P(t): U.S. Published Patent Application No. 2005/0124903 A1 (Luchy Roteliuk et al., 09 Jun. 2005, “,Pressure based System and Method for Determining Cardiac Stroke Volume”). Thus, one way to estimate the SV is to apply the relationship: [0000] SV=Kσ ( P )= Kstd ( P )  (Equation 4) [0026] where K is a scaling factor and from which follows: [0000] CO=K σ( P ) HR=Kstd ( P ) HR   (Equation 5) [0027] This proportionality between the SV and the standard deviation of the arterial pressure waveform is based on the observation that the pulsatility of a pressure waveform is created by the cardiac SV into the arterial tree as a function of the vascular tone (i.e., vascular compliance and peripheral resistance). The scaling factor K of equations 4 and 5 is an estimate of the vascular tone. [0028] Recently, one of the present inventors also published that vascular tone can be reliably estimated using the shape characteristics of the arterial pulse pressure waveform in combination with a measure of the pressure dependant vascular compliance and the patient's anthropometric data such as age, gender, height, weight and body surface area (BSA): U.S. Published Patent No. 2005/0124904 A1 (Luchy Roteliuk, 09 Jun. 2005, “Arterial pressure-based automatic determination of a cardiovascular parameter”). To quantify the shape information of the arterial pulse pressure waveform, he used higher order time domain statistical moments of the arterial pulse pressure waveform (such as kur-tosis and skewness) in addition to the newly derived pressure weighted statistical moments. Thus, the vascular tone is computed as a function of a combination of parameters using a multivariate regression model with the following general form: [0000] K= χ(μ T1 ,μ T2 , . . . μ Tk ,μ P1 ,μ P2 , . . . μ Pk ,C ( P ), BSA, Age, G   (Equation 6) [0000] where K is vascular tone (the calibration factor in equations 4 and 5); X is a multiregression statistical model; μ 1T . . . μ kT are the 1-st to k-th order time domain statistical moments of the arterial pulse pressure waveform; μ 1P . . . μ kP are the 1-st to k-th order pressure weighted statistical moments of the arterial pulse pressure waveform; [0029] C(P) is a pressure dependent vascular compliance computed using methods proposed by Langwouters et al 1984 (“The Static Elastic Properties of 45 Human Thoracic and 20 Abdominal Aortas in vitro and the Parameters of a New Model,” J. Biomechanics, Vol. 17, No. 6, pp. 425-435, 1984); BSA is a patient's body surface area (function of height and weight); Age is a patient's age; and G is a patient's gender. [0030] The predictor variables set for computing the vascular tone factor K, using the multivariate model χ, were related to the “ 6 true” vascular tone measurement, determined as a function of CO measured through thermo-dilution and the arterial pulse pressure, for a population of test or reference subjects. This creates a suite of vascular tone measurements, each of which is a function of the component parameters of χ. The multivariate approximating function is then computed, using known numerical methods, that best relates the parameters of χ to a given suite of CO measurements in some predefined sense. A polynomial multivariate fitting function is used to generate the coefficients of the polynomial that gives a value of χ for each set of the predictor variables. Thus, the multivariate model has the following general form: [0000] χ = [ A 1 A 2 ⋯ A n ] * [ X 1 X 2 ⋯ X n ]   χ = [ A 1 A 2 ⋯ A n ] * [ X 1 X 2 ⋯ X n ] ( Equation   7 ) [0000] where A 1 . . . A n are the coefficients of the polynomial multiregression model, and X are the model's predictor variables: [0000] X n , 1 = ∏ m  ( [ μ T   1 ⋯ μ Tk μ P   1 ⋯ μ P   1 ⋯ μ Tk C  ( P ) BSA Age G ⋯ ] ^ [ P 1 , 1 ⋯ P 1 , m ⋯ ⋯ ⋯ P n , 1 ⋯ P n , m ] ) ( Equation   8 ) [0031] The method listed above relies solely on a single arterial pulse pressure measurement. Its simplicity and the fact that it does not require a calibration are advantages of this method. However, due to the empirical nature of the vascular tone assessment relationships, the accuracy of this method may be low in some extreme clinical situations where the basic empirical relationships of the model are not valid. For this reason, a second independent measurement may be beneficial if added to the basic multiregression model. [0032] As shown above, many techniques have been devised, both non-invasive and invasive, for measuring the SV and CO, and particularly for detecting vascular compliance, peripheral resistance and vascular tone. It should be appreciated that there is a need for a system and method for estimating CO, or any parameter that can be derived from or using CO, that is robust and accurate and that is less sensitive to calibration and computational errors. BRIEF DESCRIPTION OF THE DRAWINGS [0033] FIG. 1 illustrates an example of two blood pressure curves representing two different arterial pressure measurements received from a subject according to an embodiment of the invention. [0034] FIG. 2 illustrates an example of an Electrocardiogram measurement (ECG) and a blood pressure measurement received from a subject according to an embodiment of the invention. [0035] FIG. 3 is a graph illustrating the relationship between the arterial pulse pressure propagation time and the arterial compliance according to an embodiment of the invention. [0036] FIG. 4 is a graph illustrating the relationship between the pulse pressure propagation time and vascular tone on patients recovering from cardiac arrest according to an embodiment of the invention. [0037] FIGS. 5-6 are graphs illustrating the correlation between the pulse pressure propagation time and vascular tone for different hemodynamic conditions of the subjects according to several embodiments of the invention. [0038] FIGS. 7-9 are graphs illustrating the correlation between the CO computed using the pulse pressure propagation time, Continuous Cardiac Output (CCO) and CO values measured by thermodilution bolus measurements (TD-CO) for different hemodynamic states of the subjects according to several embodiments of the invention. [0039] FIG. 10 is a graph showing the relationship between the CO estimated using the arterial pressure propagation time according to several embodiments of the invention and CO estimated using the arterial pulse pressure signal. [0040] FIG. 11 is a block diagram showing an exemplary system used to execute the various methods described herein according to several embodiments of the invention. [0041] FIG. 12 is a flow chart showing a method according to an embodiment of the invention. SUMMARY OF THE INVENTION [0042] One embodiment of the invention provides a method for determining a cardiovascular parameter including receiving an input signal corresponding to an arterial blood pressure measurement over an interval that covers at least one cardiac cycle, determining a propagation time of the input signal, determining at least one statistical moment of the input signal, and determining an estimate of the cardiovascular parameter using the propagation time and the at least one statistical moment. [0043] One embodiment of the invention provides an apparatus for determining a cardiovascular parameter including a processing unit to receive an input signal corresponding to an arterial blood pressure measurement over an interval that covers at least one cardiac cycle, determine a propagation time of the input signal, determine at least one statistical moment of the input signal and determine an estimate of the cardiovascular parameter using the propagation time and the at least one statistical moment. DETAILED DESCRIPTION [0044] Methods and systems that implement the embodiments of the various features of the invention will now be described with reference to the drawings. The drawings and the associated descriptions are provided to illustrate embodiments of the invention and not to limit the scope of the invention. Reference in the specification to “one embodiment” or “an embodiment” is intended to indicate that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least an embodiment of the invention. The appearances of the phrase “one embodiment” or “an embodiment” in various places in the specification are not necessarily all referring to the same embodiment. Throughout the drawings, reference numbers are re-used to indicate correspondence between referenced elements. [0045] In broadest terms, the invention involves the determination of a cardiac value, such as a stroke volume (SV), and/or a value derived from the SV such as cardiac output (CO), using the arterial pulse pressure propagation time. The arterial pulse pressure propagation time may be measured by using arterial pressure waveforms or waveforms that are proportional to or derived from the arterial pulse pressure, electrocardiogram measurements, bioimpedance measurements, other cardiovascular parameters, etc. These measurements may be made with an invasive, non-invasive or minimally invasive instrument or a combination of instruments. [0046] The invention may be used with any type of subject, whether human or animal. Because it is anticipated that the most common use of the invention will be on humans in a diagnostic setting, the invention is described below primarily in use with a “patient.” This is by way of example only; however, it is intended that the term “patient” should encompass all subjects, both human and animal, regardless of setting. [0047] FIG. 1 illustrates an example of two blood pressure curves representing two different arterial pressure measurements received from a subject. The top curve represents a central arterial pressure measurement detected from the subject's aorta and the bottom curve represents a measurement detected from the subject's radial artery. The pulse pressure propagation time (t prop ) can be measured as the transit time between the two arterial pressure measurements. [0048] The rationale of using the pulse pressure propagation time for hemodynamic measurements is based on a basic principle of cardiovascular biomechanics. That is, if the subject's heart pumped blood through a completely rigid vessel, upon contraction of the heart, the pressure waveform would instantaneously be present at any distal arterial location in the subject's body. However, if the subject's heart pumped blood through a compliant vessel, upon contraction of the heart, the pressure waveform would be present some amount of time after the heart contracted at a distal arterial location in the subject's body. [0049] The pulse pressure propagation time can be measured invasively or non-invasively at several different locations on the pressure waveform (or any other waveform related to the pressure waveform). In the example shown on FIG. 1 , the pulse pressure propagation time may be measured by using two different arterial pressure measurements, for example, one reference measurement from the aorta and one peripheral measurement from the radial artery. [0050] FIG. 2 illustrates an example of using an electrocardiogram signal as a reference signal for the propagation time measurement. The top curve represents an electrocardiogram (ECG) signal detected with electrodes placed near the subject's heart and the bottom curve represents an arterial pressure measurement detected from the subject's peripheral artery. In this example, the arterial pulse pressure propagation time (t prop ) may be measured by using the transit time between the ECG signal and the peripheral arterial pressure. Similarly, a transthoracic bioimpedance measurement could be used as a reference site, and the propagation time could be measured as a transit time versus a peripheral measurement derived from or proportional to the arterial blood pressure, [0051] The arterial pulse pressure propagation time provides an indirect measure of the physical (i.e., mechanical) properties of a vessel segment between the two recording sites. These properties include primarily the elastic and geometric properties of the arterial walls. The properties of the arterial walls, for example their thicknesses and lumen diameters, are some of the major determinants of the arterial pulse pressure propagation time. As a result, the pulse pressure propagation time depends mainly on the arterial compliance. [0052] FIG. 3 illustrates an example where the pulse pressure propagation time increases with increasing arterial compliance (C). Hence, the pulse pressure propagation time (t prop ) can be represented as a function of arterial compliance (C), i.e., [0000] t prop =f ( C )  (Equation 9) [0053] The arterial pulse pressure propagation time can therefore be used as a simple measure to estimate the arterial compliance. The propagation time can be used as a separate measure to assess a patient's vascular status or can be used in a pulse contour cardiac output algorithm along with other parameters to account for the effects of vascular compliance, vascular resistance and vascular tone. In one embodiment, the arterial pulse pressure propagation time is measured using an arterial pulse pressure signal from relatively large arteries (e.g., radial, femoral, etc.) and therefore the influence of the peripheral resistance is minimal. Also, this measurement may include the average arterial compliance between the measurement sites and may not reflect the pressure dependence of the arterial compliance. [0054] The basic relationship could be derived from the well known Bramwell-Hill equation used to calculate the pulse wave velocity (PWV): [0000] PWV 2 =  P  V · 1 ρ · V ( Equation   10 ) [0000] where dP is the change in pressure; dV is the change in volume; ρ is the blood density; and V is the baseline volume. [0055] The arterial compliance (C) may be defined as the ratio of the incremental change in volume (dV) resulting from an incremental change in pressure (dP), i.e., [0000] C =  V  P ( Equation   11 ) [0056] Substituting equation (11) into equation (10), we obtain the following equation: [0000] PVW 2 = 1 C · 1 ρ · V ( Equation   12 ) [0057] On the other hand PWV is defined as follows: [0000] PWV = L t prop ( Equation   13 ) [0058] where L is the vascular length between the two recording sites and t prop is the arterial pulse pressure propagation time. [0059] If equation 13 is substituted into equation 12, the arterial compliance can be given by: [0000] C = 1 L 2 · 1 ρ · V · t prop 2 ( Equation   14 ) [0060] If we define γ as: [0000] γ = 1 L 2 · 1 ρ · V ( Equation   15 ) [0061] The arterial compliance can be represented as: [0000] C=γ·t prop 2   (Equation 16) [0062] where the scaling factor γ is a function, which depends on the blood density, the effective vascular distance between the two recording sites and the basic volume, i.e., γ depends on the physical vascular volume between the two recording site and the blood viscosity (i.e., Hematocrit . . . etc). [0063] Based on the above equations, the arterial pulse pressure propagation time can be used in a number of different ways. [0064] 1. The use of the arterial pulse pressure propagation time to estimate arterial compliance. The pulse pressure propagation time may be used as all input to a hemodynamic model based on the standard deviation of the arterial pulse pressure to evaluate the dynamic changes in the arterial pressure created by the systolic ejection. The CO can be represented as a function of the standard deviation of the arterial pulse pressure as follow: [0000] CO=K*std ( P )* HR   (Equation 17) [0065] where K, as we have shown above, is a scaling factor proportional to the arterial compliance, std(P) is the standard deviation of the arterial pulse pressure, and HR is the heart rate. [0066] It is also understood that: [0000] CO = C · MAP τ ( Equation   18 ) [0067] where MAP is the mean arterial pressure, τ is an exponential pressure decay and C, like K, is a scaling factor related to arterial compliance. [0068] From equations 17 and 18, the scaling factor K is a measure equal to vascular compliance. If we substitute the scaling factor K in equation 17 for the compliance as given in equation 16, CO can be computed using the standard deviation of the arterial pulse pressure waveform and the arterial pulse pressure propagation time: [0000] CO = γ · t prop 2 · std  ( P ) · HR ( Equation   19 ) [0069] where standard deviation of the arterial pulse pressure can be calculated using the equation: [0000] std   ( P ) = 1 n - 1  ∑ k = 1 n  [ P  ( k ) - P avg ] 2 ( Equation   20 ) [0070] where n is the total number of samples, P(k) is the instantaneous pulse pressure, and P avg is the mean arterial pressure. The mean arterial pressure can be defined as: [0000] P avg = 1 n  ∑ k = 1 n  P  ( k ) ( Equation   21 ) [0071] FIG. 4 is a graph illustrating the relationship between the square of the arterial pulse pressure propagation time and the scaling factor K of patients during recovery from cardiac bypass surgery. FIG. 4 plots ten (10) averaged data points from ten (10) different patients. In the example of FIG. 4 , the arterial pulse pressure propagation time has been calculated as a transit time between the ECG signal and the radial arterial pressure. The data shown in FIG. 4 illustrates that the K scaling factors of equation 17 can be effectively estimated using the arterial pulse pressure propagation time as given by equation 16. [0072] FIGS. 5 and 6 are graphs illustrating the correlation between the arterial pulse pressure propagation time and the K scaling factor of equation 17 for different hemodynamic states of two subjects. Both trends correspond to animal data taken from experiments using porcine animal models. These figures show identical trends of the scaling factor K and the square of the pulse pressure propagation time. The data on FIGS. 5 and 6 illustrate that the K or the C scaling factors of equations 17 and 18 can be effectively estimated using the arterial pulse pressure propagation time. [0073] The scaling factor γ of equation 19 can be determined using any predetermined function of the propagation time and the pressure P(t); thus, [0000] γ=Γ( t prop ,P )  (Equation 22) [0000] where Γ is a pre-determined function of the propagation time and pressure, used to develop computational methods to estimate γ. [0074] Any known, independent CO technique may be used to determine this relationship, whether invasive, for example, thermodilution, or non-invasive, for example, trans-esophageal echocardiography (TEE) or bio-impedanice measurement. The invention provides continuous trending of CO between intermittent measurements such as TD or TEE. [0075] Even if an invasive technique such as catheterization is used to determine γ, it will usually not be necessary to leave the catheter in the patient during the subsequent CO-monitoring session. Moreover, even when using a catheter-based calibration technique to determine γ, it is not necessary for the measurement to be taken in or near the heart; rather, the calibration measurement can be made in the femoral artery. As such, even where an invasive technique is used to determine γ, the invention as a whole is still minimally invasive in that any catheterization may be peripheral and temporary. [0076] As discussed above, rather than measure arterial blood pressure directly, any other input signal may be used that is proportional to blood pressure. This means that calibration may be done at any or all of several points in the calculations. For example, if some signal other than arterial blood pressure itself is used as an input signal, then it may be calibrated to blood pressure before its values are used to calculate standard deviation, or afterwards, in which case either the resulting standard deviation value can be scaled, or the resulting SV value can be calibrated (for example, by setting γ properly), or some final function of SV (such as CO) can be scaled. In short, the fact that the invention may in some cases use a different input signal than a direct measurement of arterial blood pressure does not limit its ability to generate an accurate SV estimate. [0077] In addition to the blood viscosity, γ depends mainly of the physical vascular volume between the two recording sites. Of course, the effective length (L) and the effective volume (V) between the two recording sites can not be known. Vascular branching and the patient to patient differences are two main reasons why the effective physical vascular volume between the two recording sites can not be known. However, it is obvious that this physical volume is proportional to the patient's anthropometric parameters and therefore it can be estimated indirectly using the patient's anthropometric parameters. The anthropometric parameters may be derived from various parameters such as the measured distance (l) between the two recording sites, patient's weight, patient's height, patient's gender, patient's age, patient's bsa, etc., or any combination of these factors. In one embodiment, all the anthropometric parameters, for example, the distance (l) between the two recording sites, patient's weight, patient's height, patient's gender, patient's age and patient's bsa, may be used to compute γ. Additional values are preferably also included in the computation to take other characteristics into account. In one embodiment, the heart rate HR (or period of R-waves) may be used. Thus, [0000] γ=Γ M ( l,H,W,BSA, Age, G,HR )  (Equation 23) [0078] Where [0000] l is the measured distance between the two recording sites; H is the patient's height; W is the patient's weight; BSA is the patient's bsa; Age is the patient's age; G is the patient's gender; HR is the patient's heart rate; and ΓM is a multivariate model. [0079] The predictor variables set for computing γ, using the multivariate model Γ, are related to the “true” vascular compliance measurement, determined as a function of CO measured through thermo-dilution and the arterial pulse pressure, for a population of test or reference subjects. This creates a suite of compliance measurements, each of which is a function of the component parameters of Γ M . The multivariate approximating function is then computed using numerical methods that best relates the parameters of Γ M to a given suite of CO measurements in a predefined manner. A polynomial multivariate fitting function is used to generate the coefficients of the polynomial that give a value of Γ M for each set of the predictor variables. Thus, the multivariate model has the following general equation: [0000] Γ M = [ a 1 a 2 ⋯ a n ] * [ Y 1 Y 2 ⋯ Y n ] ( Equation   24 ) [0080] where a 1 . . . a n are the coefficients of the polynomial multiregression model, and Y are the model's predictor variables: [0000] Y n , 1 = ∏ m  ( [ l H W BSA Age G HR ] ^ [ P 1 , 1 ⋯ P 1 , m ⋯ ⋯ ⋯ P n , 1 ⋯ P n , m ] ) ( Equation   25 ) [0081] The use of the arterial pulse pressure propagation time to estimate vascular tone. Vascular tone is a hemodynamic parameter used to describe the combined effect of vascular compliance and peripheral resistance. In the prior art, the shape characteristics of the arterial pressure waveform in combination with patients anthropometric data and other cardiovascular parameters were used to estimate vascular tone (see Roteliuk, 2005, “Arterial pressure-based automatic determination of a cardiovascular parameter”). The arterial pulse pressure propagation time can also be used to estimate vascular tone. In one embodiment, the arterial pulse pressure propagation time can be used as an independent term to a multivariate regression model to continuously estimate vascular tone. In one embodiment, the arterial pulse pressure propagation time can be used in combination with the shape information of the arterial pulse pressure waveform to estimate the vascular tone. The higher order shape sensitive arterial pressure statistical moments and the pressure-weighted time moments may be used as predictor variables in the multivariate model along with the arterial pulse pressure propagation time. Additional values are preferably also included in the computation to tale other characteristics into account. For example, the heart rate HR (or period of R-waves), the body surface area BSA, as well as a pressure dependent non-linear compliance value C(P) may be calculated using a known method such as described by Langwouters, which computes compliance as a polynomial function of the pressure waveform and the patient's age and sex. Thus, [0000] K= χ( t prop ,μ T1 ,μ T2 , . . . μ Tk ,μ P1 ,μ P2 , . . . μ pK ,C ( P ), BSA, Age, G . . . )  (Equation 26) [0082] where K is vascular tone; X is a multiregression statistical model; [0083] t prop is the arterial pulse pressure propagation time; μ 1T . . . μ kT are the 1-st to k-th order time domain statistical moments of the arterial pulse pressure waveform; μ 1P . . . μ kP are the 1-st to k-th order pressure weighted statistical moments of the arterial pulse pressure waveform; [0084] C(P) is the pressure dependent vascular compliance as defined by Langwouters et al. (“The Static Elastic Properties of 45 Human Thoracic and 20 Abdominal Aortas in vitro and the Parameters of a New Model,” J. Biomechanics, Vol. 17, No. 6, pp. 425-435, 1984); BSA is the patient's body surface area (function of height and weight); Age is the patient's age; and Gender is the patient's gender. [0085] Depending on the needs of a given implementation of the invention, one may choose not to include either skewness or kurtosis, or one may include even higher order moments. The use of the first four statistical moments has proven successful in contributing to an accurate and robust estimate of compliance. Moreover, anthropometric parameters other than the HR and BSA may be used in addition, or instead, and other methods may be used to determine C(P), which may even be completely omitted. [0086] The exemplary method described below for computing a current vascular tone value may be adjusted in a known manner to reflect the increased, decreased, or altered parameter set, Once the parameter set for computing K has been assembled, it may be related to a known variable. Existing devices and methods, including invasive techniques, such as thermo-dilution, may be used to determine CO, HR and SV est for a population of test or reference subjects. For each subject, anthropometric data such as age, weight, BSA, height, etc. can also be recorded. This creates a suite of CO measurements, each of which is a function (initially unknown) of the component parameters of K. An approximating function can therefore be computed, using known numerical methods, that best relates the parameters to K given the suite of CO measurements in some predefined sense. One well understood and easily computed approximating function is a polynomial. In one embodiment, a standard multivariate fitting routine is used to generate the coefficients of a polynomial that gave a value of K for each set of parameters t prop , HR, C(P), BSA, μ 1P , σ O , μ 3P , μ 4P μ 1T , σ T , μ 3T , μ 4T . [0087] In one embodiment, K is computed as follows: [0000] K = [ A 1 A 2 ⋯ A n ] * [ X 1 X 2 ⋯ X n ] ( Equation   27 ) [0088] where [0000] X n , 1 = ∏ m  ( [ t prop , μ T   1 , μ T   2 , …   μ T   2 , μ P   1 , μ P   2 , …   μ Pk , C  ( P ) , BSA , Age , G   … ] ^ [ P 1 , 1 ⋯ P 1 , m ⋯ ⋯ ⋯ P n , 1 ⋯ P n , m ] ) ( Equation   28 ) [0089] 3. The use of the arterial pulse pressure propagation to directly estimate CO is discussed below. [0090] The pulse pressure propagation time may be used as an independent method to estimate CO. That is, the arterial pulse pressure propagation time is independently proportional to SV, as shown below: [0000] SV = K p · 1 t prop ( Equation   29 ) [0091] CO can be estimated if we multiply equation 29 by HR: [0000] CO = K p · 1 t prop · HR ( Equation   30 ) [0092] The sealing factor K p can be estimated using a direct calibration, for example, using a known CO value from a bolus thermo-dilution measurement or other gold standard CO measurement. FIGS. 7-9 are graphs illustrating the correlation between the CO computed using the pulse pressure propagation time as shown in equation 30 (COprop), Continuous Cardiac Output (CCO) and CO values measured by intermittent thermodilution bolus measurements (ICO). CCO and ICO are measured using the Vigilance monitor manufactured by Edwards Lifesciences of Irvine, Calif. The measurements have been performed on animal porcine models in different hemodynamic states of the animals, These graphs show experimentally that changes in CO are related to changes in the pulse pressure propagation time and that the pulse pressure propagation time can be used as an independent method to estimate CO. [0093] The scaling factor K p of equation 30 can be determined using any predetermined function of the propagation time and CO or SV. Any independent CO technique may be used to determine this relationship, whether invasive, for example, thermo-dilution, or non-invasive, for example, transesophageal echocardiography (TEE) or bio-impedance measurement. The invention provides continuous trending of CO between intermittent measurements such as TD or TEE. [0094] Even if an invasive technique such as catheterization is used to determine K p , it may not be necessary to leave the catheter in the patient during the subsequent CO-monitoring session. Moreover, even when using catheter-based calibration technique to determine K p , it may not be necessary for the measurement to be taken in or near the heart; rather, the calibration measurement can be made in the femoral artery. As such, even where an invasive technique is used to determine K p , the method is still minimally invasive in that any catheterization may be peripheral and temporary. [0095] The approach shown in equation 30 allows measuring CO to be performed completely non-invasively if non-invasive techniques are used to measure the propagation time and if a predefined function or relationship is used to measure K p . The non-invasive techniques to measure the propagation time can include, but are not limited to: ECG, non-invasive arterial blood pressure measurements, bio-impedance measurements, optical pulse oximetry measurements, Doppler ultrasound measurements, or any other measurements derived from or proportional to them or any combination of them (for example: using Doppler ultrasound pulse velocity measurement to measure the reference signal near the heart and using a bio-impedance measurement to measure the peripheral signal . . . etc). [0096] The scaling factor K p , depends mainly on blood viscosity and the physical vascular distance and volume between the two recording sites. Of course, the effective length (L) and the effective volume (V) between the two recording sites can not be known Vascular branching and the patient to patient differences are two main reasons why the effective physical vascular volume between the two recording sites can not be known. However, the physical volume may be proportional to the patient's anthropometric parameters and therefore it can be estimated indirectly using the patient's anthropometric parameters. The anthropometric parameters may be derived from various parameters such as the measured distance (L) between the two recording sites, patient's weight, patient's height, patient's gender, patient's age, patient's bsa etc., or any combination of these parameters. In one embodiment, all the anthropometric parameters: the distance (L) between the two recording sites, patient's weight, patient's height, patient's gender, patient's age and patient's bsa are used to compute K p . Thus, [0000] K p =M ( L,H,W,BSA, Age, G )  (Equation 31) [0097] where L is the measured distance between the two recording sites; H is the patient's height; W is the patient's weight; BSA is the patient's bsa; Age is the patient's age; G is the patient's gender; and M is a multivariate linear regression model. [0098] The predictor variables set for computing K p , using the multivariate model M, are related to the “true” CO measurement, determined as a function of the propagation time, where CO is measured through thermodilution, for a population of test or reference subjects. This creates a suite of measurements, each of which is a function of the component parameters of M. The multivariate approximating function is then computed using numerical methods that best relates the parameters of M to a given suite of CO measurements in some predefined sense. A polynomial multivariate fitting function is used to generate the coefficients of the polynomial that give a value of M for each set of the predictor variables. Thus, the multivariate model has the following equation: [0000] M = [ a 1 a 2 ⋯ a n ] * [ Y 1 Y 2 ⋯ Y n ] ( Equation   32 ) [0099] where a 1 . . . a n are the coefficients of the polynomial multiregression model, and Y are the model's predictor variables: [0000] Y n , 1 = ∏ m  ( [ l H W BSA Age G HR ] ^ [ P 1 , 1 ⋯ P 1 , m ⋯ ⋯ ⋯ P n , 1 ⋯ P n , m ] ) ( Equation   33 ) [0100] FIG. 10 is a graph showing the relationship between the CO estimated using equation 17 (CO std on the x-axis) and CO estimated using equation 30 (CO prop on the y-axis) from a series of animal experiments. The data shows CO measurements from a total of ten (10) pigs. Three (3) selected data points from each pig are used for the graph. In order to cover a wide CO range, each selected data point corresponds to a different hemodynamic state of the pig: vasodilated, vasoconstricted and hypovolemic states, respectively. The proportionality shown in FIG. 10 is experimental proof of the effectiveness and the reliability of using the propagation time to estimate CO. [0101] FIG. 11 is a block diagram showing an exemplary system used to execute the various methods described herein. The system may include a patient 100 , a pressure transducer 201 , a catheter 202 , ECG electrodes 301 and 302 , signal conditioning units 401 and 402 , a multiplexer 403 , an analog-to digital converter 405 and a computing unit 500 . The computing unit 500 may include a patient specific data module 501 , a scaling factor module 502 , a moment module 503 , a standard deviation module 504 , a propagation time module 505 , a smoke volume module 506 , a cardiac output module 507 , a heart rate module 508 , an input device 600 , an output device 700 , and a heart rate monitor 800 . Each unit and module may be implemented in hardware, software, or a combination of hardware and software. [0102] The patient specific data module 501 is a memory module that stores patient data such as a patient's age, height, weight, gender, BSA, etc. This data may be entered using the input device 600 . The scaling factor module 502 receives the patient data and performs calculations to compute the scaling compliance factor. For example, the scaling factor module 502 puts the parameters into the expression given above or into some other expression derived by creating an approximating function that best fits a set of test data. The scaling factor module 502 may also determine the time window [t 0 , tf] over which each vascular compliance, vascular tone, SV and/or CO estimate is generated. This may be done as simply as choosing which and how many of the stored, consecutive, discretized values are used in each calculation. [0103] The moment module 503 determines or estimates the arterial pulse pressure higher order statistical time domain and weighted moments. The standard deviation module 504 determines or estimates the standard deviation of the arterial pulse pressure waveform. The propagation time module 505 determines or estimates the propagation time of the arterial pulse pressure waveform. [0104] The scaling factor, the higher order statistical moments, the standard deviation and the propagation time are input into the stroke volume module 506 to produce a SV value or estimate. A heart rate monitor 800 or software routine 508 (for example, using Fourier or derivative analysis) can be used to measure the patient's heart rate. The SV value or estimate and the patient's heart rate are input into the cardiac output module 507 to produce an estimate of CO using, for example, the equation CO=SV*HR. [0105] As mentioned above, it may not be necessary for the system to compute SV or CO if these values are not of interest. The same is true for the vascular compliance, vascular tone and peripheral resistance. In such cases, the corresponding modules may not be necessary and may be omitted. For example, the invention may be used to determined arterial compliance. Nonetheless, as FIG. 11 illustrates, any or all of the results, SV, CO, vascular compliance, vascular tone and peripheral resistance may be displayed on the output device 700 (e.g., a monitor) for presentation to and interpretation by a user. As with the input device 600 , the output device 700 may typically be the same as is used by the system for other purposes. [0106] The invention further relates to a computer program loadable in a computer unit or the computing unit 500 in order to execute the method of the invention. Moreover, the various modules 501 - 507 may be used to perform the various calculations and perform related method steps according to the invention and may also be stored as computer-executable instructions on a computer-readable medium in order to allow the invention to be loaded into and executed by different processing systems. [0107] While certain exemplary embodiments have been described and shown in the accompanying drawings, it is to be understood that such embodiments are merely illustrative of and not restrictive on the broad invention, and that this invention not be limited to the specific constructions and arrangements shown and described, since various other changes, combinations, omissions, modifications and substitutions, in addition to those set forth in the above paragraphs, are possible. Those skilled in the art will appreciate that various adaptations and modifications of the just described preferred embodiment can be configured without departing from the scope and spirit of the invention. Therefore, it is to be understood that, within the scope of the appended claims, the invention may be practiced other than as specifically described herein.

A method and apparatus for determining a cardiovascular parameter including receiving an input signal corresponding to an arterial blood pressure measurement over an interval that covers at least one cardiac cycle, determining a propagation time of the input signal, determining at least one statistical moment of the input signal, and determining an estimate of the cardiovascular parameter using the propagation time and the at least one statistical moment.

CROSS-REFERENCE TO RELATED APPLICATION [0001] The present application claims priority of Korean Patent Application Number 10-2013-0164098 filed on Dec. 26, 2013, the entire contents of which application are incorporated herein for all purposes by this reference. BACKGROUND OF INVENTION [0002] 1. Field of Invention [0003] The present invention relates to a head lamp in a vehicle. More particularly, the present invention relates to a head lamp in a vehicle of which luminance efficiency is increased. [0004] 2. Description of Related Art [0005] In general, the head lamp in the vehicle is also called as a head light or a head lamp which is a lamp to light a front direction for safe running of the vehicle at night or in a dark space. Though it was mostly circular before, currently a lamp having a unique shape and structure is increasingly matched with a design of a vehicle body. [0006] The head lamp in a vehicle is made to have a light beam therefrom to be shifted in up/down directions for preventing a driver of an opposite vehicle from being dazzled by the light beam emitted from the head lamp. According to a safety standard, it is a regulation that a high beam is required to identify an obstacle existing at 100 m ahead of the vehicle and a low beam is required to identify an obstacle existing at 40 m ahead of the vehicle. [0007] In order to implement such a high beam and a low beam, there is a shield interposed between a light source and a lens. The shield is made to shield a portion of the light incident on the lens from the light source or a reflector. And, according to a shape and movement of the shield, the high beam or the low beam is implemented, selectively. [0008] However, since the light shielded by the shield is failed to be used as an effective light of the head lamp, there may be a limit of head lamp efficiency. And, if the luminance efficiency of the light passing through the shield is too low, the head lamp efficiency may become poor in comparison to a performance of the light source. [0009] The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art. SUMMARY OF INVENTION [0010] The present invention has been made in an effort to provide a head lamp in a vehicle having improved luminance efficiency. Accordingly, the present invention, created for solving above and/or other problems, is to provide a head lamp in a vehicle which can improve luminance efficiency. And, the present invention is to provide a head lamp in a vehicle which can improve a performance of high beam with a simple configuration. [0011] According to various aspects of the present invention, a head lamp in a vehicle may include a light source for emitting a light, a reflector for reflecting the light forward from the light source, a lens for transmitting the light being forwarded toward a front from the light source and the reflector, a holder having one end coupled to the lens and the other end coupled to the reflector to make the lens spaced alt a predetermined distance from the reflector, and a movable shield disposed between the light source and the reflector and the lens for selectively shielding a portion of the light being forwarded toward the lens from the light source and the reflector, or not shielding the portion of the light being forwarded toward the lens from the light source and the reflector when being moved to create a space between the movable shield and a lower end of the holder to allow the light pass through. [0012] The movable shield may shield the portion of the light being forwarded toward the lens with one side, and the light emitted to the space formed between the movable shield and the lower end of the holder from the light source when the movable shield is moved may be reflected at the other side of the movable shield and directed to the front. [0013] The light reflected at the other side of the movable shield and directed to the front may produce a high beam. [0014] The movable shield may be hinge coupled to the holder and movable by a hinge motion. The head lamp may further include a solenoid connected to the movable shield for moving the movable shield upon having power supplied thereto. [0015] The head lamp may further include a fixed shield provided between the movable shield and the lens and having one side for shielding the portion of the light being forwarded toward the lens from the light source and the reflector and the other side for absorbing lights reflected and scattered by an inside surface of the holder and by an inside surface of the lens. [0016] The movable shield may be hinge coupled to the fixed shield and movable by a hinge motion. The head lamp may further include a solenoid coupled to the fixed shield connected to the movable shield for moving the movable shield upon having power supplied thereto. [0017] The head lamp may further include an elastic member provided to a portion at which the movable shield and the fixed shield are hinge coupled for returning the movable shield to an original position if power supply to the solenoid is cut off. [0018] The reflector may have a stopper formed thereon for being brought into contact with the moving movable shield for preventing the hinge motion of the movable shield from progressing excessively by the solenoid. The stopper may be formed to prevent impact of contact with the movable shield. [0019] The head lamp may further include a buffer portion formed at a portion the fixed shield is to be brought into contact with the movable shield for preventing an impact of contact with the fixed shield when the movable shield returns to the original position by the hinge motion owing to the elastic member. [0020] The methods and apparatuses of the present invention have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following Detailed Description, which together serve to explain certain principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS [0021] FIG. 1 illustrates a perspective view of an exemplary head lamp in a vehicle in accordance with the present invention. [0022] FIG. 2 illustrates an exploded perspective view of an exemplary head lamp in a vehicle in accordance with the present invention. [0023] FIG. 3 illustrates a longitudinal half sectional view of an exemplary head lamp in a vehicle in accordance with the present invention, before a movable shield is moved. [0024] FIG. 4 illustrates a schematic view showing moving of a movable shield in an exemplary head lamp in a vehicle in accordance with the present invention. [0025] FIG. 5 illustrates a longitudinal half sectional view of an exemplary head lamp in a vehicle in accordance with the present invention, after a movable shield is moved. [0026] FIG. 6A illustrates a schematic view showing a movable shield in an exemplary head lamp in a vehicle in accordance with the present invention, returning to an original position. [0027] FIG. 6B is a partially enlarged view of FIG. 6A . DETAILED DESCRIPTION [0028] Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims. [0029] FIG. 1 illustrates a perspective view of a head lamp in a vehicle in accordance with various embodiments of the present invention, and FIG. 2 illustrates an exploded perspective view of a head lamp in a vehicle in accordance with various embodiments of the present invention. Referring to FIGS. 1 and 2 , the head lamp in a vehicle 1 in accordance with various embodiments of the present invention includes a light source 80 , a reflector 70 , a lens 20 , a lens seating ring 10 , a holder 30 , a fixed shield 40 , a movable shield 50 , and a solenoid 60 . [0030] The light source 80 functions to receive electric energy and convert the electric energy received thus to light energy. And, the light source 80 includes a light emitting portion 82 . The light emitting portion 82 is a portion the light energy converted thus, i.e., a light, is emitting therefrom. Moreover, the light emitting portion 82 is arranged in the head lamp 1 . [0031] The reflector 70 is coupled to the light source 80 , and the light emitting portion 82 of the light source 80 is placed in, and arranged on an inner side of, the reflector 70 . And, the reflector 70 is provided to reflect at least a portion of the light emitted from the light emitting portion 82 of the light source 80 toward a front of the head lamp 1 . Moreover, the reflector 70 is formed in a half cut eclipse shape or substantially in a half cut eclipse shape. The shape of the reflector 70 may be the same as or similar to those in the art, and thus more detailed description of the shape of the reflector 70 will be omitted. [0032] The lens 20 is provided to focus the light emitted from the light emitting portion 82 and direct the light to the front of the head lamp 1 . And, an overall shape of the lens 20 is formed in a circular shape that is an overall shape of a general lens. Moreover, in order to achieve a required aberration correction state with a small number of faces, the lens 20 may be an aspherical lens. [0033] The lens seating ring 10 is formed in an annular shape to surround the circular lens 20 . And, the lens 20 is seated on an inside circumference of the lens seating ring 10 . [0034] The holder 30 has a cylindrical shape or substantially a cylindrical shape in overall with opened both sides for coupling to the main lens 20 and the lens seating ring 10 . And, in a state a circular circumference of the lens 20 is in contact with a circumference of the opened one side of the holder 30 , as the annular lens seating ring 10 is coupled to the holder 30 while surrounding the lens 20 , the holder 30 and the lens 20 are coupled, together. [0035] The fixed shield 40 is interposed between the light emitting portion 82 and the lens 20 . And, the fixed shield 40 is formed to have a plate shape for shielding a portion of the light forwarded toward the lens 20 from the light emitting portion 82 of the light source 80 and the reflector 70 . In the meantime, the plate shape of the fixed shield 40 has one side for shielding a portion of the light forwarded toward the lens 20 , and the other side for absorbing the lights reflected and scattered at an inside surface of the holder 30 and an inside surface of the lens 20 . In this case, the fixed shield 40 is arranged such that the one side of the fixed shield 40 faces a rear of the head lamp 1 , and the other side of the fixed shield 40 faces the front of the head lamp 1 . [0036] The fixed shield 40 is coupled to the other opened side of the holder 30 . And, the other opened side of the holder 30 is coupled to the reflector 70 , and the fixed shield 40 is interposed between the other side of the holder 30 and one end of the reflector 70 . That is, the holder 30 is arranged to space the lens 20 and the fixed shield 40 as much as a width of the holder 30 . [0037] The movable shield 50 is interposed between the reflector 70 and the fixed shield 40 . And, the movable shield 50 is coupled to, such as hinge coupled to, a lower end of the fixed shield 40 . Moreover, the movable shield 50 is formed to have a plat shape. In the meantime, the plate shape of the movable shield 50 has one side formed for shielding the light, and the other side formed for reflecting the light. In the meantime, the hinge coupling of the movable shield 50 is not limited to the lower end of the fixed shield 40 , but the hinge coupling of the movable shield 50 may be to the holder 30 . [0038] The solenoid 60 is coupled to the fixed shield 40 , and provided for making the movable shield 50 hinge coupled to the fixed shield 40 to make a hinge motion. In this case, the solenoid 60 may be an ON/OFF solenoid 60 which is operated in two stages of ON or OFF depending on supply or cut off of power thereto. [0039] The lens seating ring 10 has an extended coupling portion 12 formed thereon extended toward the holder 30 from the annular circumference of the holder 30 for coupling to the holder 30 , the holder 30 has a two ended coupling portion 32 formed thereon having one end for coupling to the extended coupling portion 12 and the other end for coupling to the reflector 70 , and the reflector 70 has a holder coupling portion 72 for coupling to the other end of the holder coupling portion 32 . That is, by coupling of the extended coupling portion 12 , the two ended coupling portion 32 , and the holder coupling portion 72 , the lens seating ring 10 , the holder 30 and the reflector 70 are coupled together. [0040] Formed on the fixed shield 40 , there are a securing portion 42 extended from the plate shape of the fixed shield 40 for coupling to the holder 30 to secure the fixed shield 40 , a solenoid coupling portion 44 extended from the plate shape of the fixed shield 40 for the solenoid 60 to couple thereto, and a movable shield coupling portion 46 extended from the plate shape of the fixed shield 40 for hinge coupling to the movable shield 50 . In the meantime, the holder 20 has a fixed shield coupling portion 34 formed thereon additionally for coupling to the securing portion 42 . [0041] Formed on the movable shield 50 , there are a hinge portion 56 for hinge coupling to the fixed shield 40 , and a solenoid connection portion 58 for connection to the solenoid 60 . [0042] The solenoid 60 includes a movable portion 62 movable as the power is supplied or cut off thereto/therefrom, and the solenoid connection portion 58 of the movable shield 50 is connected to the movable portion 62 of the solenoid 60 . And, the solenoid connection portion 58 is moved by movement of the movable portion 62 , which makes the movable shield 50 to move. [0043] FIG. 3 illustrates a longitudinal half sectional view of a head lamp in a vehicle in accordance with various embodiments of the present invention, before a movable shield is moved. Referring to FIG. 3 , before movement, the movable shield 50 is arranged to shield a light proceeding toward the lens 20 reflected at the reflector 70 to form the high beam or a light proceeding toward the lens 20 , directly. That is, the movable shield 50 has one side arranged to shield the light proceeding toward the lens 20 from the reflector 70 and the light emitting portion 82 . In this case, a light not shielded by the movable shield 50 is directed to and transmitted through the lens 20 to form the low beam, and the other side of the fixed shield 40 arranged in front of the movable shield 50 functions to absorb reflected and scattered lights. [0044] FIG. 3 illustrates that paths of the light shielded by the movable shield 50 and the light transmitting through the lens 20 to form the low beam are shown in solid lined arrows, and the reflected and scattered lights absorbed to the other side of the fixed shield 40 are shown in dotted arrow line(s). [0045] FIG. 4 illustrates a schematic view showing moving of a movable shield in accordance with various embodiments of the present invention. Referring to FIG. 4 , if the movable shield makes the hinge motion as power is supplied to the solenoid 60 , and the movable portion 62 of the solenoid 60 is moved, a space is opened, through which a light can pass between a lower end of the holder 30 and the hinge portion 56 . In this case, the hinge portion 56 is arranged below the lower end of the holder 30 , and the movable shield 50 makes the hinge motion in a direction moving away from the lower end of the holder 30 centered on the hinge portion 56 . In this case, in order to prevent the hinge motion of the movable shield from progressing excessively, the reflector 70 has a stopper 74 formed thereon to be brought into contact with the movable shield 50 being moved thus. And, the stopper 74 is formed to absorb an impact caused by the hinge motion of the movable shield 50 . [0046] FIG. 5 illustrates a longitudinal half sectional view of a head lamp in a vehicle in accordance with various embodiments of the present invention, after a movable shield is moved. Referring to FIG. 5 , after the movement, the movable shield 50 is arranged to form a space through which a light can pass between the fixed shield 40 and the movable shield 50 . In this case, the light emitted from the light emitting portion 82 of the light source 80 through the space formed between the fixed shield 40 and the movable shield 50 is reflected at the other side of the movable shield 50 and directed to form the high beam, and the light shielded by one side of the movable shield 50 before the movable shield 50 is moved transmits through the lens 20 and developed to form the high beam. Therefore, a high beam directing area is enlarged than a case when only the light transmitting through the lens 20 forms the high beam. In the meantime, the light which transmits through the lens 20 and is developed to form the low beam may always be developed without being shielded. [0047] FIG. 5 shows paths of lights transmitting through the lens 20 to form the low beam and the high beam and lights reflected at the other side of the movable shield 50 to form the high beam with dotted arrow line(s). [0048] FIG. 6 illustrates a schematic view showing a movable shield in accordance with various embodiments of the present invention, returning to an original position. FIG. 6A is a partially enlarged view of FIG. 6 . Referring to FIGS. 6 and 6A , if the movable shield 50 returns to an original position as power supply to the solenoid 60 is cut off, and movement of the movable portion 62 of the solenoid 60 is stopped, the space is closed, through which the light can pass between the lower end of the holder 30 and the hinge portion 56 . In this case, the hinge portion 56 has an elastic member 90 provided thereto, and the movable shield 50 makes a hinge motion in a direction the movable shield 50 is returned to an original position by elastic force of the elastic member 90 as power supply to the solenoid 60 is cut off. In this case, the movable shield 50 may be brought into contact with the fixed shield 40 as the movable shield 50 returns to the original position, and the fixed shield 40 has a buffer portion 48 formed thereon for being brought into contact with the other side of the movable shield 50 and absorbing an impact caused by the hinge motion of the movable shield 50 . [0049] Thus, the head lamp in a vehicle in accordance with various embodiments of the present invention can increase utilization efficiency of the light emitted from the light emitting portion 82 by utilizing the light shielded by the movable shield 50 . And, the enlarged high beam directing area enables to improve and secure vehicle running safety owing to movement of the movable shield 50 . [0050] For convenience in explanation and accurate definition in the appended claims, the terms “upper” or “lower”, “front” or “rear”, and etc. are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures. [0051] The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents.

A head lamp in a vehicle may include a light source for emitting a light, a reflector for reflecting the light forward from the light source, a lens for transmitting the light being forwarded toward a front from the light source and the reflector, a holder having one end coupled to the lens and the other end coupled to the reflector to make the lens spaced at a predetermined distance from the reflector, and a movable shield disposed between the light source and the reflector and the lens for selectively shielding a portion of the light being forwarded toward the lens from the light source and the reflector, or not shielding the portion of the light being forwarded toward the lens from the light source and the reflector when being moved to create a space between the movable shield and a lower end of the holder to allow the light pass through.

This is a continuation of application Ser. No. 15,334 filed Feb. 26, 1979, and now abandoned. FIELD OF THE INVENTION This invention relates generally to denominational gaming tokens and more particularly to novel improvements in combination metal and plastic injection-molded gaming tokens. These tokens have specific utility as difficult-to-counterfeit casino chips of varying chosen monetary denominations. BACKGROUND In my U.S. Pat. No. 3,968,582, issued on July 13, 1976, I disclose and claim novel denominational gaming tokens (casino chips) and related injection-molding fabrication processes wherein these chips are constructed using total chip assembly techniques which makes these chips or tokens very difficult to counterfeit. At the same time, however, novel tokens are produced with sharp durable and permanent indicia color lines thereon which render these tokens readily distinguishable as to denomination, origin, etc. at normal game distances by players and gaming house personnel alike. Thus, not only did my above-identified invention overcome smear problems associated with loss of color definition in "paint-on indicia" type casino tokens, but it also eliminated the metal-to-cloth edge wear problems caused by metal inlay type casino chips. Additionally, this patented process makes token counterfeiting difficult by improving the total control which the final token assembler may exercise over the completed token. THE INVENTION The general purpose of this invention is to provide still further new and useful improvements in the above type of combination metal-and-plastic gaming tokens. These improvements to be described are manifested in an improved one-piece annular ring and metal coin retention construction which makes token disassembly difficult, simplifies token fabrication and also improves fabrication yields. To achieve this purpose and realize these improvements, I have provided a gaming token which includes a relatively flat non-metallic annular ring having parallel major surfaces and concentric minor edge surfaces, with the inner edge surface defining a central opening of the ring. Injection-molded indicia regions are selectively spaced around and on the annular ring, flush with the major surfaces thereof, and are bounded by good, sharp and durable color lines. A coin-support annulus extends from the inner minor edge surface of the ring and into the central opening thereof by a predetermined distance. This coin-support annulus is integral with the non-metallic annular ring and is configured so as to receive on each side thereof back-to-back metal slugs or discs and permanently retain these metal slugs or discs in place on its opposing surfaces. When these discs are positioned on this coin-support annulus located in the central opening of the ring and flush with the major surfaces of the annular ring and then bonded or spot-welded together at their abutting surfaces, they become very difficult to remove by the average casino player or user of the token. Advantageously, this metal coin-support annulus may be made integral with a single unitary flat annular ring member which has been preconstructed to receive, in surface cavity regions and in a coplanar or flush fashion therewith, injection-molded indicia regions. These indicia regions may be formed during a single-step injection-molding operation. Accordingly, it is an object of this invention to provide a new and improved combination metal and plastic gaming token which is difficult to disassemble and which is straightforward in its method of manufacture. Another object of this invention is to provide a new and improved gaming token of the type described which may be constructed with one (rather than two) non-metallic annular rings and which possesses most, if not all, of the advantages of the invention described in my U.S. Pat. No. 3,968,582. Another object is to provide these above-described mutually compatible novel features of the present invention which require less total fabrication piece parts and lower overall fabrication costs relative to my above-patented process. A feature of this invention is the provision of a novel gaming token of the type described which includes a fluorescent or otherwise visually detectable dye directly incorporated into the injection-molded indicia regions of the token, thereby enabling the token to be readily identified as to its legitimacy or origin. Another feature is the provision of a novel gaming token of the type described which includes a thin coil retention annulus for receiving abutting metal coins flush with the non-metallic annular ring of the token. These and other objects and features of this invention will become more readily apparent in the following description of the preferred embodiments thereof, as illustrated in the accompanying drawings. DRAWINGS FIGS. 1a through 1e illustrate one annular ring member embodiment of the invention, using a single annular preform, whereas FIGS. 2a through 2d illustrate the matched preform pair annular ring construction according to the invention. FIG. 1a is a perspective view of a completely assembled casino token embodying the invention. FIG. 1b is an enlarged fragmented cross-sectional view taken along lines b--b of FIG. 1a. FIG. 1c is a perspective view of the single annular preform member used in the construction of FIG. 1a. FIG. 1d is a plan view of the non-metallic annular preform in FIG. 1c. FIG. 1e is an enlarged cross-section view taken along lines e--e of FIG. 1d. FIG. 2a is a perspective view of a completely assembled double preform casino token embodying the invention. FIG. 2b is an enlarged fragmented cross-section view taken along lines b--b of FIG. 2a. FIG. 2c is an exploded perspective view of the casino token of FIG. 2a. FIG. 2d is an enlarged fragmented cross-section view taken along lines d--d of FIG. 2c. FIGS. 3a through 3h illustrate, respectively, the process for assembling a single hexagonal metal coin in a flat non-metallic annular ring, using a novel convex-to-concave metal-to-non-metal edge surface contour which enables good permanent coin retention within the annular ring. FIGS. 4a-4b illustrate further alternative embodiments of my invention exhibiting different, useful coin-retention configurations (geometries) for the metal coin or disc and the non-metallic annular ring, respectively. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now in sequence to FIGS. 1a through 1e, there is shown in FIG. 1a, in perspective view, a completed metal-and-plastic gaming token which is designated generally at 10 and which includes a flat annular non-metallic ring member 12. The unitary annular ring member 12 includes therein a plastic preform and molding material to be further described and is constructed by initially providing a single non-metallic annular ring preform 14, configured as indicated in FIG. 1b and FIG. 1c. This plastic preform 14 in FIG. 1c can be stamped out or injection-molded in any desired configuration using well-known injection-molding techniques, and preferably will include symmetrically spaced indicia patterns around the annulus of the preform. These patterns are defined in FIGS. 1a through 1e in part by a plurality of upstanding vertical members or posts 16 which are integral with and extend perpendicular to a thin flat annular rib member 14. The thick vertical posts 16 and the thinner annular rib 14 integral therewith are adapted to receive, in a coplanar fashion to be described, an injection-molding compound 20 (as shown in FIG. 1 b) which differs in color from that of the preform. In this manner, the preform 14 and molding compound 20 define selectively spaced color patterns which may be used to indicate either the origin, ownership or denomination of the token. In addition, these color patterns may be configured to further include integral upstanding letters or numbers (not shown) which are spaced along the portions of the rib 18 between the vertical posts 16. Such patterns may, for example, include lettering such as "MGM" or "HARVEYS" which have a vertical extent equal to that of the vertical posts 16. Thus, a hot liquid molding compound 20 of a color different from that of the annular preform 14 may be injected around all of the vertical posts 16 and additional chosen identifying lettering (not shown) therebetween. This may be accomplished using, for example, the injection-molding process and apparatus disclosed in my above-identified U.S. Pat. No. 3,968,582. Referring now in more detail to the particular annular geometry of the non-metallic preform shown in FIGS. 1b through 1e, the vertical posts 16 which form part of one major outer surface area are alternately spaced between smaller closely spaced vertical post pairs 22, each having a trapezoidal shaped upper surface area. These upper surface areas of the vertical posts 16 and 22 ultimately become coplanar with the surrounding injection-molding compound 20 (FIG. 1b) which also flows into the cylindrical mast or trough 24 and is there retained by a cylindrical upstanding wall 26. The upper surface of the cylindrical upstanding wall 26 is also coplanar with the molding compound 20 and with the previously identified trapezoidal shaped surfaces of the upstanding vertical posts 16 and 22. The flat annular rib 14, the vertical posts 16 and 22, and the cylindrical molding compound retaining wall 26 are all integral, one with another, and are formed, as mentioned, as a single annular unitary non-metallic preform member. An inner non-metallic coin retention annulus 28 is also an integral part of this preform and is located, as shown, at the midpoint of the inner annular surface of the cylindrical upstanding retaining wall 26. This coin retention annulus 28 is adapted to receive abutting metallic discs or coins on its opposing upper and lower major surfaces. The coin retention annulus 28 is relatively thin so that coins can be mounted on the opposing surfaces thereof and then spot-welded together at or near the center of the annulus 28. Thus, as shown in FIG. 1b, the two metal coins 30 and 32 have their outer indicia surfaces 34 and 36 coplanar with the outermost major surfaces of the injection-molded preform 14 and are thereby difficult to remove by hand after being welded or bonded together, as described. The non-metallic preform 14 described above also includes a plurality of radially extending tabs 38 which are positioned as shown at the outer periphery of the preform and are ultimately made radially coextensive with the injection-molding compound 30. Thus, during an injection-molding operation, these radial tabs will abut the cylindrical walls of an injection-molding apparatus (not shown) and interrupt the flow of the injection-molding compound when the compound is compressed around the preform and its previously identified parts. Referring now to FIGS. 2a through 2b, the assembled token in FIG. 2a includes a pair of matched and aligned plastic preform members 50 and 52 generally of the type described in my above U.S. Pat. No. 3,968,582. These plastic preforms 50 and 52 are configured to receive injection molding 54 which flows in and around the offset regions thereof, and in this embodiment of my invention, the molding compound, upon cooling, sets to form and define a radial rib member 56, an inner annular rim member 58, and a coin retention annulus 60 which are all integral, one with another. The coin-support annulus 60 receives a pair of metal coins 62 and 64, as indicated in FIGS. 2b and 2c. This construction thus enables the outer surfaces of the metal coins 62 and 64 to be flush and coplanar with the outer upper surfaces of the non-metallic annular ring which surrounds it and formed by the previously identified preform and molding compound members 50, 52 and 58, as shown in FIG. 2b. Referring now to FIGS. 2c and 2d, the two matched preforms each have rectangular markers 66 located at the 120 degree positions of the token and on the center lines 68 of the three injection-molding indicia regions 70. The size and spacing and color of these regions 70 may, of course, be varied to indicate a particular token denomination or other characteristic of the token, and these regions 70 will preferably contain a fluorescent dye or the like which readily distinguishes the token and enables it to be identified as to its legitimacy. The gaming tokens shown in both of the above embodiments of the invention may be finally assembled by one source, e.g., the inventor or his assignee, under strict security control, rather than a vendor source, and this feature minimizes the risk of token theft. Additionally, during final token assembly metallic coins of these tokens may be multi-colored by the selective application of paint or etchant, and alternatively of self-adhesive label or cover may be applied over the metallic coins in lieu of an embossment, painted or etched feature. The diameter and thickness of the gaming tokens described above can be readily changed to suit specific requirements, and the particular method of injection-molding used in token fabrication easily lends itself to making such changes in token size. Thus, where a long series of initials or a relatively large logo (or both) are to be used in the preform or preforms between the vertical posts thereof, an increase in preform diameter, width and major surface area will accommodate such an added space requirement. Referring now in sequence to FIGS. 3a through 3h, there is shown in FIG. 3a a combination plastic-metal gaming token 80 including an outer flat non-metallic (plastic) annular ring 82 which may be constructed using injection-molding processes described in my U.S. Pat. No. 3,968,582 and may be of either the one-preform or two-preform construction. Using the one-preform construction, the central portion 84 of the ring is the plastic preform, and the upper and lower portions 86 and 88 of the ring are formed by injecting a molding compound around this preform 84 in the manner generally taught in my U.S. Pat. No. 3,968,582. The injection molds (not shown) are configured to produce an inner hexagonal-shaped edge surface which is generally designated 90 in FIG. 3a, and a hexagonal shaped metal coin 91 is press-fitted into the central opening of the non-metallic annular ring 82 in a manner to be described. However, the contour of the coin edge is not limited to six sides and may include other polygons which are compatible with coin retention specifications and economical manufacturing techniques. Referring now to FIGS. 3b and 3c, the inner hexagonal edge of the non-metallic annular ring in FIG. 3b has a downwardly extending surface segment 92 which meets with the upwardly extending surface segment 94 at a central horizontal plane which extends through the vertical center of the opening in the annular ring 82. Both of these inner edge surface segments 92 and 94 are molded to an approximate 10 degree angle θ with respect to vertical and thereby define a convex inner edge surface which is a mirror image of the concave outer edge surface of the hexagonal-shaped metal coin or disc 91 once the disc 91 is press-fit into the annular ring 82. Referring now to FIGS. 3d and 3e, the metal coin 91 has an upstanding outer rim or edge 98 with a thickness which is slightly greater than the thickness of the annular ring 82. This novel metal coin construction is particularly advantageous for two reasons, as will be illustrated in FIG. 3f. Firstly, the upstanding rim 98 is adapted to receive a work piece 100 in a press-fit downward motion of member 100 and prevent any surface-to-surface contact between the major surface area 102 of the metal coin 91 and the contact surface area 104 of the press-fit work piece 100. This feature is desirable from the standpoint of minimizing scratching and abrasing of the metal coin 91 during its press-fit with the non-metallic annular ring 82. Secondly, during the above press-fit operation, as illustrated in FIG. 3f, the press-fit contact outer edge surfaces 106 and 108 of the metal coin 91 are enabled to be deformed radially inward with some ease as a result of the particular geometry of the rim 98 of the coin 91 as force is exerted, as indicated at the arrows 110 and 112. The above metal-coin-deformation process is illustrated in more detail in FIGS. 3g and 3h wherein, in the initial downward stroke of the work piece 100, the coin 91 is moved from the relative position of FIG. 3f to the position shown in FIG. 3g. Although the metal coin 91 never comes to a "rest" position, as illustrated in FIG. 3g, in large scale production of these gaming tokens, the coin 91 does pass through the coin-to-annular ring relative vertical position shown in FIG. 3g where the horizontal center line 114 of the coin 91 is precisely registered with the vertex 116 of the annular ring 82, thereby enhancing token symmetry once the metal-to-plastic press-fit operation is completed. Once the continuing downward thrust of the work piece 100 presses the coin 91 in a downward motion indicated by the arrow 118, the abutting metal and plastic outer and inner edge surfaces of the coin and ring, respectively, as shown in FIG. 3g, begin to "mate" or conform, as shown in FIG. 3h. Thus, the particular rim geometry of the metal coin 91 and the ability of the coin 91 to be deformed radially inward enables the metal coin 91 to transform the vertical press-fit motion of the work piece 100 into a lateral or horizontal deformation movement and thereby cause the completed press-fit geometry of the ring and token to assume the conforming and surface-abutting geometry, as illustrated in FIG. 3d. However, the shapes of the work pieces 100 and 101 in FIG. 3f are only exemplary in nature and may include other configurations, such as for example, two identical solid polyhedrons with cross-sections identical to that of the coin being stamped into place. Thus, by mere inspection of the completed convex-concave conforming surface geometry of the metal coin-plastic annular ring structure of FIG. 3h, it will be appreciated that the metal coin 91 will be extremely difficult to pry away and remove from its surrounding and retaining annulus. Referring now to FIGS. 4a and 4b, there are shown two alternative embodiments of coin retention within the scope of my invention. In FIG. 4a, the metal coin 120 is machined so as to leave an outer rim or shoulder 122 which is contoured as shown to fit into the recessed area 124 of the adjoining annular ring 126. The ring 126 has an upper tab or flap 128 which is deformable and, during token assembly, is bent clockwise 90 degrees so as to conform to the upper surface 130 of the coin's rim 122. This metal-to-plastic fitting step may be accomplished, for example, by initially ultrasonically softening the upstanding flap 128 and then either ultrasonically bonding the plastic flap 128 to the metal or, alternatively, using thermocompression bonding techniques to press the respective metal and plastic edges of the members 120 and 126 in uniform and symmetrical edge-abutting relationship. Thus, after assembly, the structure in FIG. 4a will closely resemble the structure in FIG. 4b. Referring now to FIG. 4b, there is illustrated the "mold-around-the-coin" approach to token construction wherein the metal coin 132 is initially laid in place in an injection-molding apparatus (not shown), but generally of the same type of injection-molding apparatus that is shown and described in my above U.S. Pat. No. 3,968,582. Then, a hot molding compound is injected under pressure in a predefined volume of space surrounding the coin 132 to thereby form the non-metallic annular ring 134, with the C-shaped outer edge geometry which conforms to the mesa edge construction of the metal coin 132. Although the invention described above makes frequent reference to sharp and durable color lines which are achievable in the non-metallic annular ring of the token, it is obviously within the scope of this invention to use preform and a molding compound of the same color if a non-metallic ring of one color is desired for any particular reason. Various other modifications may be made in the above-described embodiments without departing from the true scope of this invention. For example, the invention is in no way limited to a circular and cylindrical token configuration as shown in the drawings, but may instead utilize rectangular, triangular, elliptical, square, or various other odd-shaped configurations within the scope of the appended claims. It is also within the scope of this invention to vary the size and geometrical configurations of the upstanding protrusions on the non-metallic preforms of the annular ring as well as to vary the colors of both of these protrusions and the color of the injection molding surrounding these protrusions. Additionally, the present invention is not limited to the spot-welding of the metal coins in the center of the non-metallic annular ring, and will include any bonding process such as ultrasonic or thermo-compression bonding, which is suitable for securing these metal coins one to another by fusion. Furthermore, these metal coins may assume any geometry other than the circular and hexagonal shapes of the preferred embodiments and may be secured in place in the center of the non-metallic annular ring in any arrangement where the outer major surfaces of these metal coins are substantially flush with the adjacent major surfaces of the annular ring. Obviously, the word "flush" is intended to include metal-to-non metal adjacent surface offsets of several mils or more, and such offsets may be necessary for, or a result of, the stamping process used for bonding or welding these coins together, or bonding a single coin into, the central annulus of the non-metallic annular ring.

The specification describes an improved gaming token which includes, among other features, a relatively flat non-metallic annular ring having injection-molded indicia thereon bounded by sharp and durable color lines. This ring also includes an inner coin-support annulus which extends into a central opening of the ring and receives flat back-to-back metal slugs or discs on each surface thereof to retain these discs permanently in place once they are welded together. Since the outer coin surfaces are flush with the major surfaces of the flat non-metallic annular ring, this construction renders removal of the metal coins quite difficult. In one embodiment of the invention, this coin-support annulus is integral with a single unitary plastic annular ring which includes regions of injection-molded indicia thereon which are flush with both major and minor surfaces of the ring and are bounded by the sharp and durable color lines as noted above.

[0001] This application claims the benefit of U.S. Provisional Application No. 60/125,078, filed Mar. 19, 1999, which is incorporated herein by reference. [0002] This application is a continuation-in-part and claims the benefit of U.S. patent application Ser. No. 09/303,499, filed Apr. 30, 1999, which is incorporated herein by reference. [0003] The subject matter of this application is related to the subject matter of U.S. patent application entitled MACHINE-ASSISTED TRANSLATION TOOLS, Ser. No. 09/071,900, filed May 4, 1998, which is co-pending, and is hereby incorporated by reference. BACKGROUND OF THE INVENTION [0004] 1. Field of the Invention [0005] This invention relates to a network-based workflow management system, and more particularly, to a system suitable to coordinate the assignment and fulfillment of tasks over a network. [0006] 2. Description of the Related Technology [0007] Outsourcing is one of the most prevalent trends in today's business environment. Nearly every company outsources some part of its business. For example, the accounts receivable collections, janitorial, and payroll functions are outsourced so frequently that it has become, over the last few decades, an accepted method for running those functions. Other functions are being outsourced with more regularity, such as computer services, benefits administration, telephone customer support, and records management. Some functions are only being outsourced by a few companies, and may require a number of years before they are more widely outsourced. These functions include engineering, financial analysis, document translation and management. [0008] Many organizations have found that outsourcing projects, tasks or functions can be advantageous if such outsourcing has the effect of reducing transaction costs. Downes and Mui, Unleashing the Killer App Digital Strategies for Market Dominance , Harvard Business School Press, Boston Mass., 1998. Therefore, organizations seeking to outsource a project will submit a request for proposal to at least one service provider to obtain a quote or price for completing the project. Once the service provider has returned the proposal with a quote for completing the services, the organization will evaluate the quotes for service and select a service provider to carry out the project. The organization may use a variety of criteria to determine which service provider to select, such as the service provider's price, qualifications and reputation. Usually, the competition between service providers results in lower end cost for the organization. However, this system has no mechanism for allowing the electronic delivery of a work product or allowing completed projects or portions of any completed projects to be stored and used as a resource for subsequent projects. [0009] By the same token, state and local governments have used contract bidding to purchase products and services, such as computers, building contractors or road maintenance equipment. Contract bidding is a process that in certain circumstances might reduce transaction costs due to the competition in bidding. In general, the contract bidding process is similar to outsourcing; for example, bids are collected, bids are evaluated and service providers are selected. This system also has no mechanism for allowing the electronic delivery of a work product or allowing completed projects or portions of any completed projects to be stored and used as a resource for subsequent projects. [0010] An extraordinary effort is expended by some contractors to track organizations that outsource contracts or place contract awards up for bid. On-line services, such as BidNet, can collect information regarding various organizations requesting bids for projects. Usually, an on-line service collects bid request information from different agencies, e.g., state and local governments, hospitals, universities, etc., and the on-line service will provide this information to qualified contractors. For example, once a contractor has registered with the on-line service and the service has received an agency's bid request that pertains to goods or services provided by the contractor, the on-line service will generate a summary that includes bidding information, such as the agency issuing the bid, the deadline for submitting a bid, where the products and/or service must be delivered and any special specifications the agency may require. Accordingly, the summary will be mail to the contractor to assist him in determining whether to bid on the contract. While this system has the advantage of notifying a contractor of possible contracts with minimal effort required by contractor, it has the disadvantage of not providing a complete electronic workflow management system. Additionally, the on-line service does not allow users to recycle any previously completed work. Moreover, the system does not provided electronic work product delivery. [0011] Another bidding and selling method is an auction. Auctions provide a popular and exciting marketplace for buying and selling property. Many ordinary individuals are denied access because they are required to attend an auction in person to place a bid on an item for sale. This requirement limits participation in the auction to those people who live near the auction site or those people who can afford the time and expense to travel to the auction site. [0012] Many attempts have been made to solve the problem of gaining bid access to an auction without having to be physically present at an auction site. For example, U.S. Pat. No. 4,789,928 issued to Fujisaki on Dec. 6, 1988 describes an auction information processing system which enables individuals spread over a wide area to participate in an on-line auction. The system includes a host computer connected via communication lines to many remote terminals of individual bidders. The individual bidders enter bids from their remote terminals and the current highest bid and eventual winning bid are displayed in real-time on the remote terminals. While this system has the advantage of allowing a large number of individual bidders to participate in an on-line auction, it has the disadvantage of not allowing electronic workflow management. Furthermore, the system does not provided electronic product delivery. [0013] Another computerized bidding system is disclosed in U.S. Pat. No. 4,903,201 issued to Wagner on Feb. 20, 1990. Wagner describes an automated futures trading exchange wherein bids to purchase or offers to sell a particular commodity contract are made by exchange members through remote terminals connected to an exchange computer. The exchange computer matches offer prices and bid prices to complete trading transactions. The system does not provided electronic product delivery. [0014] Another system for conducting a competitive bidding procedure is disclosed in U.S. Pat. No. 5,243,515 issued to Lee on Sep. 7, 1993. Lee describes a secure teleprocessing bidding system for enabling construction subcontractors to submit bids to a general contractor for a particular construction job. Subcontractors use an ordinary telephone to dial into a central bidding computer and enter their bids. At the close of the bidding session, the central computer prints a summary report of all bids received, and the summary report is mailed or faxed to all participating bidders. As in the previous bidding systems, this system has no mechanism for allowing the electronic delivery of a work product or allowing completed projects to be stored and used as a resource for subsequent projects. [0015] In addition to the on-line auctions mention above, on-line auctions are now being conducted over the Internet. One such auction is Save the Earth Foundation has an Artrock Auction that is described at their world-wide web site http://www.commerce.com/save_earth. To participate in the auction, bidders register and submit bids for auction items through the Internet. Bidders are notified by electronic mail when a bid higher than their own is placed on an item. The winning bidder is also contacted by electronic mail at the close of the bidding session. The Artrock Auction has no mechanism to allow electronic delivery of the product. [0016] Similarly, Ebay has an on-line auction, as described at their world-wide web site http://www.ebay.com. In this auction system, bidders also register and submit bids through the Internet. Items for sale are graphically displayed on the bidders' screens, in addition to the bid information for each item. Bid information is updated hourly throughout each two week bidding session. Unfortunately, like the previously mentioned on-line auctions, Ebay's auction has no mechanism for allowing electronic delivery of a product. [0017] Similarly, Christie's International describes an on-line auction at their world-wide web site http://www.christies.com. In Christie's auction, bidders register and submit bids in the same manner as the Ebay auction. Christie's on-line auction also suffers from the same disadvantage as the Ebay auction in that it has no mechanism to allow a product to be delivered electronically. SUMMARY OF THE INVENTION [0018] An object of the invention is to provide a marketplace for supervised contract bidding, electronic product delivery, payment and arbitration. [0019] Another object of the invention is to provide subjects and operators access to a workflow management clearinghouse. A further object of the present invention is to provide such access over the Internet using a standardized interface format, such as Hyper Text Markup Language (HTML). [0020] Another object of the invention is to provide user access to a clearinghouse's database(s) by entering information into electronic forms. [0021] Another object of the invention is to provide a complete workflow management system which utilizes E-Commerce technology. [0022] Another object of the invention is to provide a system that pools available projects and provides a live “real-time” bidding environment. [0023] Another object of the invention is to permit photos, images and/or videos that correspond to an available project to be coupled with the project's information summary for viewing. [0024] Another object of the invention is to provide a system where the only equipment subjects and operators need are communication devices with network access. [0025] Another object of the invention is to reduce the effort required to complete a project by integrating a work pre-processing capability with a workflow management system. [0026] Another object of the invention is to reduce the effort required of a translator to translate source information into target information by eliminating the need to retranslate previously translated work. [0027] Another object of the invention is to provide a paperless workflow management system. [0028] Another object of the invention is to reduce the amount of time or effort required to translate source text by automatically converting placeables, e.g., dates and measurement units, for insertion into a target text. [0029] Another object of the invention is to automatically change the appearance of placeable elements to a target language format if appropriate, for example, by converting measurement units, date formats, currency values and units, titles and names, etc. [0030] Another object of the invention is to semiautomatically insert translation units at a user-defined position in the target text upon interaction from the user, e.g., upon one or more keystrokes, upon one or more spoken commands, upon mouse clicks, etc., when translating source information. [0031] Another objective of the invention is to provide translation memories or mini-translation memories for different subject matters. [0032] Another objective of the invention is to match subjects' projects with operators at competitive prices. [0033] According to the invention these objects are accomplished by a system that manages bidding and workflow where the work performed is the manipulation or delivery of electronic information. The system is particularly suited for workflow management for language or other translations, document editing, contracting for creating works of authorship such as graphics, plans software, and even data processing. [0034] The foregoing objects may be accomplished by a clearinghouse that provides workflow management. Accordingly, the clearinghouse may have a computer with software components that may accept information from users (i.e., subjects and/or operators) over a network. In addition, the clearinghouse may accept registration information, requests and bids for projects, project information, and authorizations to Credit or debit a user's account. [0035] According to a feature of the workflow management system, a clearinghouse may be provided to bring together organizations requiring outsourcing of a service (subjects) and service providers (operators). The clearinghouse manages the bidding and awarding of contracts, by collecting and authorizing requests for proposals (RFPs), sending bid invitations to operators that meet the requirements of the subject, sending a notification that the contract has been awarded, collecting payment from the outsourcing company and paying the service provider. [0036] According to a feature of the invention, the clearinghouse may electronically provide to the operator information regarding the topic/subject a project along with the work product. Moreover, the completed work product may be returned to the subject electronically. [0037] According to a feature of the invention, a clearinghouse may be provided to incorporate specialized translation memories, which are translation databases that collect translations as they are performed, along with the source language equivalents. After a translation has been performed and stored into a translation memory, the translation memory may be accessed to assist a translator with new translations where the new translations include identical or similar source language text as the source language equivalents included in the translation memory. If a subject has a document requiring translation, the system will first check whether any parts of the document can be pre-translated using a translation memory. Accordingly, the subjects and operators may use the pre-translation information to determine an acceptable bid price. In other words, the system allows a human translator to translate only what is new in a document, and evaluate the cost for translating only the new information. [0038] According to a feature of the invention, a clearinghouse may maintain a database to track when a translator creates a new translation unit or segment, i.e., a sentence pair with one source sentence and then a corresponding translation in the target language. A translator sends this pair back to the clearinghouse where the system stores the pair in a translation memory with the translator's name or user ID. When another translator reuses the translation unit, the original translator will receive a credit for his work. What is more, a translator may earn royalties on his translation units, in order to provide translators an incentive to share their translations with translators. [0039] According to the invention a workflow management system may be provided that manages a computer bidding process for a translation project, awards the translation project to a translator and delivers a completed translation electronically to a subject. [0040] A workflow management system may be provided with at least one project coordination computer module whose actions are directed by software components and at least one fulfillment computer module whose actions are directed by software components, and linked to said at least one project coordination computer module. The workflow management system may also be provided with at least one fulfillment computer module. [0000] In addition, the software components in these computer modules operate in concert as a work flow management and work product delivery system. [0041] These, together with other objects and advantages which will be subsequently apparent, reside in the details of construction and operation as more fully hereinafter described in the claims, with reference being had to the accompanying drawings forming a part thereof, wherein like numerals refer to like elements throughout. BRIEF DESCRIPTION OF THE DRAWINGS [0042] FIG. 1 shows an embodiment of the invention; [0043] FIG. 2 shows another embodiment of the invention; [0044] FIG. 3 shows another embodiment of the invention; [0045] FIG. 4A shows another embodiment of the invention; [0046] FIG. 4B shows another embodiment of the invention; [0047] FIG. 5 shows another embodiment of the invention; [0048] FIG. 6 shows another embodiment of the invention; [0049] FIG. 7 shows another embodiment of the invention; [0050] FIG. 8 shows another embodiment of the invention; [0051] FIG. 9 shows another embodiment of the invention; [0052] FIG. 10A shows another embodiment of the invention; [0053] FIG. 10B shows another embodiment of the invention; [0054] FIG. 11 shows another embodiment of the invention; [0055] FIG. 12 shows another embodiment of the invention; and [0056] FIG. 13 shows another embodiment of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT [0057] FIG. 1 shows a clearinghouse implementing the workflow management system. The clearinghouse may be a computer 101 with at least one electronic storage apparatus, e.g., database, which buyers (subjects) and sellers (operators) may access using an input interface 105 , 107 , i.e., computer, wireless or landline telephone, television or personal digital assistant, with a network connection 103 A, 103 B. FIG. 1 shows the input devices 105 , 107 connected by two separate networks, however, a single or integral network may be implemented. Preferably, information may be exchanged electronically over the network between the operators, subjects and the clearinghouse by methods, such as HTML forms, e-mail, fax. Accordingly, the clearinghouse may use electronic forms to request and/or collect information from the operator and subject: for example, user ID, password, project description, maximum bid price, bids, contact information, payment information, project criteria for example, where the project is a request for translation, the project criteria might include the target language, the source language, the subject or category that the text belongs to, the project due date, and how to award the project. In practice, the electronic forms may be downloaded from a computer module at or remote from the clearinghouse to the user's communications device, or instead, the forms may be completed directly over the Internet. Furthermore, the clearinghouse may provide an audio access and conversion system that allows an operator and/or subject to access information originally formatted for interfacing on a computer network via a telephone. Moreover, a firewall may be provided at the clearinghouse to screen the integrity of the data. [0058] The clearinghouse may have different computer modules or systems for accomplishing the workflow management task: for example, project coordination, registration, financial, credential and verification check, project fulfillment, royalty tracking, bid management. Preferably, each module or system may be a computer module with an algorithm to accept information and complete the task required by the module. FIG. 2 illustrates the components of a generic module with connections to a remote user: for example, computer 18 , on-line form templet 27 , form 32 , optional database 60 , network connection 24 , remote computer 30 and user 38 (may be a subject or an operator). User 38 at remote computer 30 may access on-line form template 27 residing on computer 28 . As illustrated in FIG. 2 , template 27 contains a form 32 , which may be displayed to user 38 on the screen of remote computer 30 . Accordingly, subjects and/or operators may communicate with the clearinghouse by using electronic forms or any other known methods for collecting information over a network. In addition, the computer modules may be separate modules, however, the modules may be integrated to provided a single unit. Furthermore, the modules may store the information in an integrated database or in separate databases, which may be located at the clearinghouse or at a remote location. [0059] According to a preferred embodiment of the present invention, a project coordination module may be provided by a clearinghouse, which may manage the flow of a project, for example, from the time a bid request is received until the completed project or completed work product is delivered. First, a subject may submit to a project coordination module or the clearinghouse project information or a request for proposal (RFP), which may provide an operator with information: such as, the subject's background, a description of the projects, tasks or functions that require outsourcing, the specific task to be bid upon by an operator, the subject's expectations for the operator's performance, and/or a deadline for bid submission. In an alternative embodiment, shown in FIG. 3 , a subject may submit information regarding specifics concerning a translation project, e.g., filename 302 , source language ( 304 , 330 ), target language ( 306 , 332 ), subject matter ( 308 , 334 ), a list of individual translators ( 310 , 336 ) or translator group ( 314 , 340 ) from whom bids should be solicited, translator's residency ( 312 , 338 ). Accordingly, a subject may submit this information by accessing an on-line “New Projects” HTML template 27 residing on computer 28 . Template 27 may contain a New Projects Request form which may be displayed to the subject 38 on the screen of remote computer 30 . After the subject completes the form, the information may be transmitted to the clearinghouse for processing, where the project coordination module uses the information to conduct the bidding process or to send a request to the bid management module to initiate the bidding process. [0060] Accordingly, the workflow management system may use only the New Projects Request form to collect data for the bidding process, or the system may use both the New Projects Request form and the complete project specifications and requirements, i.e., work subject or work product, to collect data for the bidding process. Therefore, in an alternative embodiment, the complete project specifications and requirements may be electronically transmitted (uploaded) in a text format or in a graphical format, e.g., photos, images and/or videos, to the clearinghouse or project coordination module to aid in the bidding process. The uploaded complete project specifications and requirements may be the actual project, e.g., a document requiring translation, a request for a patent search, a request for information or a paper on a particular topic, etc., or a photo, diagram, or schematic depicting the project, e.g., construction site, a circuit that requires fabrication, etc. According to an optional embodiment, the project coordination module may provide an image relating to the project that may be viewed in its entirety or may allow only limited portions to be viewed. The a preview image may provide an operator with sufficient information to allow him to determine his bid price for a project. [0061] When a subject's new project arrives at the clearinghouse, a request may sent to a project fulfillment module, which checks a fulfillment database, to determine if any previously completed projects or portions of any completed projects may be used as a resource in connection with the new project. Accordingly, the fulfillment database may transmit fulfillment parameters, i.e., an evaluation of the relevant resources that may be reused in the new project, to the project coordination module, which may provide the fulfillment parameters to the users to assist them in negotiating a bid price. Alternately, the project fulfillment module may provide the fulfillment parameters directly to the users. The project fulfillment module and fulfillment database will be discussed in more detail below. [0062] According to an optional embodiment, the project coordination module may send a request to a bid management module to commence the bidding process. The bid management module may work together with the project coordination module to complete the bidding process or the bid management module may handle the entire bidding process. For example, the bid management module may advise the project coordination module when an operator has been selected for the project ( FIG. 20 ). In addition or alternatively, the bid management module or the project coordination module may send bid invitations and/or bid award notifications to the operator and/or subject, such as an e-mail, electronic broadcast message or voice mail. As illustrated in FIG. 5 , the invitations and notifications may be posted on the clearinghouse's web site 520 . Furthermore, the bid management module may send a selection of operator bids to the project coordination module for the subject's selection ( FIG. 21 ). The bid management module will be discussed in detail later. [0063] Once the bid has been awarded, the project coordination module may transmit the work subject, i.e., the complete project and/or specifications and requirements to the selected operator. When the project is completed and if the project lends itself to such, the selected operator may submit the completed project or completed work product to the project coordination module. It should be appreciated that these may be completely paperless transactions, which deliver the work product or project in an electronic format. Preferably, the project coordination module may provide the subject with a preview of the operator's completed project before agreeing to payment and electronically receiving (downloading) the project ( FIG. 15 ). Of course, the project may be downloaded by the subject without previewing the document. Furthermore, if the subject is dissatisfied with the quality of the project, the project coordination module may allow the subject to reject the project and request that the project be corrected. If the project is rejected, the project coordination module may transmit the project to the selected operator for corrections. Once the corrections are completed, the project coordination module may transmit the corrected project to the subject for approval. Moreover, the project coordination module may also provide an arbitration means. [0064] According to an embodiment of the present invention, a registration module may be provided by the clearinghouse, which may classify registrants as subjects or operators. As stated above, the subject and/or operator registration modules may be separate modules, however, a single or integrated module/system may be provided. Preferably, the registration system may be a computer module with an algorithm to accept user (i.e., subject and/or operator) registration information. Accordingly, a user may register with the clearinghouse by using electronic forms or any other known method for collecting registration information over a network. Furthermore, the registration modules may store the information in a single integrated database or separate databases, which may be located at the clearinghouse or at a remote location. [0065] Referring to the chart of FIG. 6 , an operator may access the clearinghouse's registration module, preferably, by a network connection. An operator 38 at remote computer 30 may access on-line “Registration” HTML template 27 residing on computer 28 ( 602 ). As illustrated in FIG. 2 , template 27 may contains an Operator's Registration Form, which may displayed to operator 38 on the screen of remote computer 30 ( 604 ). Reference is now made to FIG. 7 , which illustrates an Operator Registration Form, an operator may register with the clearinghouse by entering information into the form ( 606 ): for example, organization's name ( 702 ), translator's name ( 704 , 706 ), address ( 708 , 710 , 712 ), e-mail address ( 714 ), telephone number ( 716 ), and type of e-commerce payment ( 718 ), source languages ( 720 , 732 ), target languages ( 722 , 734 ), subject areas ( 724 , 736 ) and country of residence ( 726 , 738 ). In an additional or alternative embodiment, the number of a checking account, savings account, or any other account in which operator 38 may receive payment credit may be entered into the form. Of course, the account may be debited when necessary, such as when and over payment is made or when a work product is returned. Finally, the operator may submit the information to the clearinghouse ( 608 ) by activating the register button 728 . Then, the information may be transmitted over a communication link, e.g., wireless or landline, where the information is collected and stored in a registration database, which may be at the clearinghouse or a remote location. After the information is received, a portion or portions of the information may be transmitted to a credential check module ( 610 , 622 ), e.g., operators's qualifications or credentials, and/or a financial module ( 614 , 624 ), e.g., payment information. These modules will be discuss in detail later. The operator may be notified, instantaneously or at a later time, that the registration was successful by e-mail ( 620 ). The system is not limited to e-mail notifications, for example, voice mail or fax notification may be provided. In addition, the notification may be posted or transmitted directly from the clearinghouse's web site. [0066] Reference is now made to FIG. 8 , which illustrates a chart of the subject's registration module. The subject may register with the clearinghouse in a similar fashion as the operator. A subject 38 at remote computer 30 accesses on-line “Registration” HTML template 27 residing on computer 28 ( 802 ). As illustrated, template 27 contains an Subject's Registration Form which is displayed to subject 38 on the screen of remote computer 30 ( 804 ). First, an subject may register with the clearinghouse by entering information, (e.g., organization's name ( 902 ), contact person's name ( 904 , 906 ), address ( 906 , 908 , 910 ), e-mail address ( 914 ), telephone number ( 916 )) into a Subject's Registration Form ( 806 ). The subject may submit the information to the clearinghouse ( 808 ) by activating the register button ( 928 ). Then, the information may be transmitted over a communication link, e.g., wireless or landline, where the information is collected and stored in a registration database, which may be at the clearinghouse or a remote location. After the information is received, a portion or portions of the information may be transmitted to a verification module ( 810 , 822 ), e.g., subject's claimed identity, and/or a financial module ( 814 , 824 ), e.g., payment information. These modules will be discuss in detail below. The subject may be notified, instantaneously or at a later time, that the registration was successful by e-mail ( 820 ). The system is not limited to e-mail notifications, for example, voice mail or fax notification may be provided. In addition, the notification may be posted or transmitted directly from the clearinghouse's web site. [0067] According to a preferred embodiment of the present invention, a financial module may be provided by the clearinghouse, which may link the clearinghouse to a financial institution that is equipped to handle e-commerce. Referring to FIG. 1 , the clearinghouse 101 is connected to financial institution 108 by a network 103 C, which may be a wireless or landline link. Preferably, the clearinghouse has to access to a financial institution, such as a bank or credit house, to establish new accounts or access a registered user's accounts. When a user registers with the clearinghouse, a payment account may be established automatically with the financial institution. The financial module may transmit to the financial institution information collected during the registration process: for example, user's name, financial account number, and financial account type. Alternately, the user may establish a payment account with the financial institution by submitting information, via electronic forms, through the financial module or directly with the financial institution. For example, FIG. 11 illustrates a Payment Account Creation Form 1132 . The form has three fields 54 corresponding to a user's name 44 , a financial account number 46 , and a financial account type 48 . In the preferred embodiment, financial account number 46 is a credit card number corresponding to a credit card account of user 38 . In an alternative embodiment, the financial account number 46 may be the number of a checking account, savings account, or any other account in which a user has the ability to receive/transmit payment credits/debits. Additionally, form 32 contains a button 52 for user 38 to press to transmit the completed form 32 to computer 28 . In addition, the financial module or financial institution may evaluate the subject's payment abilities and approve or deny the subject access to the clearinghouse. The financial module or financial institution may allow electronic transmission of a notification to the user indicating whether their account has been established. For example, the financial module may send an e-mail or other electronic broadcast message regarding the account's status to the user. Of course the module may provide an additional option, where by the module may generate a hard copy of the message, electronically meter the postage and sort the message for delivery. In addition, the module may allow the financial information to be updated at a later date. Once the subject's account has been established, the subject may submit a request for proposal to the clearinghouse. When the project is completed, the financial module may instruct the financial institution to deduct the funds from the subject's account. [0068] Additionally, the financial module or the financial institution may receive the operator's preferred payment method information from the operator. Once the operator's account has been established and the operator has completed a project, the financial module may instruct the financial institution to credit the operator's account with an amount equal to the negotiated price. Similarly, the financial module has the capabilities to credit the operator's account for royalties earned. The royalty information may be received from the royalty tracking module. The royalty tracking module will be discussed later. [0069] Furthermore, the financial module may evaluate and/or collect an operator's credit history and transmit this information to a credential check module, which will be discussed in detail later. Hence, the financial module may allow the clearinghouse to authorize new accounts, to verify the credit history of an operator, and to transfer funds, e.g., credit/debit a user's payment account. [0070] According to an embodiment of the present invention, an operator's credential check module may be provided by the clearinghouse, which may verify an operator's credentials and may supply this information to the subjects. The clearinghouse may optionally maintain a credential database with other information regarding an operator, such as qualifications, evaluations given by other subjects for the job performance the operators may be have performed and general comments. During registration, an operator's qualifications may transmitted to the credential check module ( 1202 ) where the information may be stored. The computer module may be programmed to check on-line sources to confirm the operator's qualifications ( 1204 ). In addition or in the alternative, the clearinghouse may conduct independent research to determine the operator's qualifications ( 1210 ), and this information may be stored in the credential database ( 1212 ). As stated previously, the clearinghouse or the credential check module may provide electronic evaluation forms for subjects to fill out regarding operators that have perform services for them. This information may be collected and maintained in the credential database. Another option that may be provided by the clearinghouse is that subjects may preview this information at any time ( 1214 ). [0071] According to a preferred embodiment of the present invention, a subject verification module may be provided, which may verify the subjects identity ( FIG. 14 ). The verification module provides an additional security feature for the work flow management system. [0072] According to a preferred embodiment of the present invention, a project fulfillment module may be provided by the clearinghouse, which may store completed projects or portions of previously completed projects in a fulfillment database to be used as a resource for subsequent projects. In addition, the clearinghouse may setup or load the fulfillment database with project resources. Preferably, the project fulfillment module may be a computer module with an algorithm to accept completed projects or portions of completed projects and store them in a fulfillment database. Moreover, the algorithm may evaluate whether any portion of a new project has been previously completed in connection with a prior project. The project fulfillment module may supply fulfillment parameters to the users. The fulfillment parameters are an evaluation of “how much” of a new project may be supplied by the fulfillment database. The project coordination module may provide the evaluation information or fulfillment parameters to the operators and/or subjects. [0073] After the project coordination module receives a project request, the project coordination module may interrogate the project fulfillment module to determine whether a similar project is stored in the fulfillment database, i.e., the database is interrogated to determine whether any stored resources may be recycled to fulfill the subject's project request. Accordingly, this information may be provided to the operator and/or the subject to assist in negotiating a bid price. [0074] For example, if none of the previously completed projects or resources stored in the fulfillment database match the newly requested project, the recycle module may notify the project coordination module, which may alert the bid management module to initiate a bid process for the subject's project request. On the other hand, if a new project request is identical to a project stored in the fulfillment database, the clearinghouse or the project coordination module may perform or complete the project without requiring an operator's assistance. Thus the project coordination module may transmit a price quote to the subject. If the subject agrees to the price, the project may be electronically delivered and the subject's payment account may be debited as discussed with respect to the financial module. The details of the document delivery transaction are discussed in detail in the description of the project coordinate module. In addition, the project fulfillment module may send a notification to the royalty tracking module, which identifies the operator that completed the original project. The details of this transaction are discussed in the description of the royalty tracking module. [0075] If the new project request is similar to a resource, a completed project or a portion of one or more of the projects stored in the fulfillment database, the clearinghouse may transmit a fulfillment parameter notification to the subject and/or operator, which indicates “how much” of the project may be recycled to assist them in determining a bid price. The project fulfillment module may send a notification to the royalty tracking module, which identifies, for example, the amount of the recycled information used in connection with the new project, the operator that originally generated the recycled information and the operator that used the recycled information in connection with the new project. As stated above, the details of this transaction are discussed in the description of the royalty tracking module. [0076] In another embodiment, the project fulfillment module may include a translation database. According to this embodiment, the translation database may collect translations as they are performed, if the translation is performed “on-line”, or after they have been performed and submitted, if they have been performed “off-line” and uploaded upon completion. In this fashion, the translation database may be updated to include new translations. This translation database may be used to “pre-translate” project documents prior to releasing them for bid. Alternatively, or in addition, after a translation project has been assigned to a translator, the translator may be given access to the translation database to assist him with performance of the assigned translation. The translation database optionally may store translations in the form of pairs or sets of translation segments comprising corresponding words or phrases in two or more languages. The clearinghouse may provide translation memories with terms that are specialized to a certain field or subject matter such as, legal, medical or business. [0077] According to another embodiment, the clearinghouse may provide translation software to assist translators with translation projects. Such translation software may be a machine-assisted tool that actively supports the translation process by automatically suggesting existing translations and terminology from the translation database. An example of a commercially available machine-assisted tool is the Translator's Workbench supplied by TRADOS GmbH (Germany). According to an optional aspect of this embodiment, a translator may perform the translation “on-line” with direct access to the translation software and the translation database, or a translator may download the translation software and relevant portions of the translation database and perform the translation “off-line.” Accordingly, the translation database optionally may be divided into subject matter, e.g., legal, medical or business, and/or language fields so that a translator need not access or download the entire translation database in performance of a particular translation. [0078] An advantage of the above-described translation database and translation software is that they make the translation process more efficient by ensuring that a translator need not translate a source segment that has already been translated. While a translator works, the translation software operates in the background to ‘learn’ original sentences and their corresponding translations. In the process, this data may be uploaded into the translation database a the clearinghouse. Concurrently, the translation software access, therewith, the translation database to rapidly find identical or similar sentences and automatically display them as a working basis for a translation in progress. [0079] Translation software is most useful when it is are able to locate not only identical matches to stored translation segments, but also approximate or “fuzzy” matches. Fuzzy matching facilitates retrieval of text that differs slightly in word order, morphology, case, or spelling. The approximate matching is necessary because of the large variety possible in natural language texts. Fuzzy matching to find sentences with similar content has seen its performance perfected by the implementation of neural network technology. The translator has the option of choosing among alternative translations in addition to the one automatically suggested by the translation memory. Along with the source sentence and its translation, each translation segment can also include information on users, dates and frequency of use, and classifying attributes and text fields. This information enables easy maintenance of translation databases, which naturally become quite large over time. [0080] According to a preferred embodiment of the present invention, a royalty tracking module may be provided by the clearinghouse, which may track or monitor when an operator's work is reused to fulfill a project. As mention above, the project fulfillment module may send a notification to the royalty tracking module, which identifies, for example, the amount of the recycled information used in connection with the new project, the operator that originally generated the recycled information and the operator that used the recycled information in connection with the new project. This may be accomplished by relating the operator's user ID to a completed project. Creators of any reused information may get credit or royalty for the use of their information. In this fashion the subsequent use of translation segments can be tracked. This tracking can be used to allocate credits of royalties to the operator that generated the translation units. Therefore, creators of any reused translation units may get credit or royalties for the use of their translation units. [0081] According to a preferred embodiment of the present invention, a bid management module may be provided by the clearinghouse, which may execute and monitor the bidding process. In addition, the module may maintain a database of qualified bidders, identify and notify qualified operators of request for bid, accept bids from the operators and award bids based on the subject criteria. [0082] The bid management module may receive information regarding a subject's request for bid either from the project coordination module or directly from the subject. Preferably, the bid module may be a computer module with an algorithm adapted to accept subject and/or operator bid information. In addition, the bid management module may perform calculations to determine the bid award. As illustrated in FIG. 3 , a subject may submit information, via the New Projects Request Form, to the bid management module regarding how to award the project: for example, maximum price ( 318 , 342 ), maximum # of bidders ( 310 , 342 ), award method ( 322 , 346 ) (i.e., automatic, manual or a combination), award date ( 324 , 348 ) award preference ( 326 , 350 ) (e.g., best price, earliest delivery date, first bidder). The bid management module need not be limited to these criteria, and other limitation may be used to determine bid awards. [0083] In addition, as illustrated in FIG. 13 , the bid management module may provide features for the subject to restrict the invitations for bid to a limit groups of bidders. For example, the subject may select the operators individually or limited the operators by different criteria, e.g., the source and target language, the project subject matter, operator's qualifications, etc. The bid management module may accept the criteria submitted by electronic forms, as discussed above. The bid management module may determine a group of qualified bidders. The bid module may send a request to the check credential module to confirm a bidder's qualifications. [0084] Once a group of qualified operators has been determined, the bid management module may notify qualified operators by an electronic notification, or a bid request may be posted on the clearinghouse's web site. Referring to FIG. 5 , the clearinghouse may provide an operator with information regarding his current status. For example, the number of current bid invitations or number of newly awarded projects. [0085] The bid management module may provide information to the operator, concerning the RFP, for example, file name or project ID, source language, target language, subject matter, total number of words, total number of translation units, number of recycled translation units, number of new words, end of bidding, date of delivery, maximum price, award criterion, award decision, maximum number of bids, status, best offer ( FIGS. 4A and 19 ). The bid management module may provide a transaction history, as depicted in FIG. 4C . The operator may review all this information and submit a bid via electronic form. The bid management module accepts bids and updates the bid preview information form FIG. 4B . The bid module may award the bid and notify the operator and/or subject. [0086] According to one embodiment of the present invention, a clearinghouse may be used to manage translators (operators) and organizations (subjects) that require document translation. When international companies enter new foreign markets and “localize” a product or service for the new market, a great deal of documentation must be translated, creating a need for cost-effective translation. The demand for translation of commercial and technical documents represents a large and growing segment of the translation market. Examples of such documents are contracts, instruction manuals, forms, and computer software. During the general course of business, many small translation jobs, which may consist of one to five pages of text on a wide variety of topics, ranging from legal text to office memos, are generated. Because commercial and technical documents are often detailed and precise, accurate translations continue to be in demand. Throughout the world, multilingual cultures and multinational trade create an increasing demand for translation services. [0087] When seeking to outsource translation work, companies must conduct research in sources like the yellow pages to locate the telephone numbers and addresses of translators. Once a translator is located, they must be contacted either by a letter or telephone to request a sample translation or to get a quotation for translation service. Research must be conducted to determine the translator's qualifications. Substantial additional work is involved before the translator starts to translate the first word. [0088] To save time and effort, documents requiring translations have been outsourced to translation agencies, which have a group of translator contractors that they hire to perform translations. This method saves time and effort; however, it increases the cost of the translation by adding a middleman and not allowing free market competition for the price of the translation. In addition, this method is limited by the agencies' contacts, geographic location and the physical exchange of the documents. [0089] The following is an example of how the workflow management system operates for document translation. A subject or organization has a document requiring translation into a target language. The subject connects to a website provided by a clearinghouse, such as http://www.XXXXX.com. If it is the first time a subject or organization is using the workflow management system, he may register with the clearinghouse by downloading an on-line Subject Registration Form and filling out the requested information, such as company name, name of contact person ( 902 ), address ( 908 , 912 ), e-mail address ( 914 ), telephone ( 916 ), type of e-commerce payment ( 918 ). Once a subject is registered, he may fill in an on-line form, a New Project Request Form ( FIG. 3 ), that describes and classifies the document requiring translation. The on-line form will request certain criteria (e.g., the target language ( 306 , 332 ), the source language ( 304 , 330 ), the subject or category that the text belongs to ( 308 , 334 ), the project due date, and how to award the project ( 322 , 324 , 326 , 346 , 348 , 350 )). By activating button 328 , the form is electronically transmitted (uploaded) to the clearinghouse along with the actual document to be translated. Of course, the subject may submit an RFP to the clearinghouse. [0090] Once the project information has been uploaded to the clearinghouse, the fulfillment database may be checked to determine how much of the project may be completed by recycling previously translation units created in performance of previous projects (translations) to generate pre-translation information, i.e., fulfillment parameters. This feature provides consistency and reduces errors, because there is no need to re-translation previously translated work. [0091] As illustrated in FIG. 16 , the project may be put into a pool of open projects for on-line bidding along with the pre-translation information. Referring to FIG. 16 , project TZ 001 is an legal document in English requiring translation into German. TZ 001 has 4,211 translation units of which 482 translation units can be recycled using relevant resources from the fulfillment database. The clearinghouse or the bid management module may notify translators (operators) with qualifications, which match the subject's bid criteria, that a translation project is available for bid ( FIG. 5 ). As see in FIG. 19 , the operator can view or preview the information provided by the subject, and make on-line price bids for completion of the translation project ( FIG. 4B ). First time operators may register with a clearinghouse in fashion similar to the subject except they enter information such as, a credit card number if they do not wish to receive monthly checks, source languages, target languages, subject areas and their country of residence. The operator may also be required to submit proof of =his qualifications. This information may be uploaded by the system or mailed into the clearinghouse for evaluation by the credential check module. [0092] Depending on the subject's bid criteria settings, a project may be awarded automatically by the bid management module, or the subject can preview the bids or a subset of bids for manual selection of the award. FIG. 20 shows a subject the bids made for project TZ 001 since the subject's criterion was for an automatic award based on price the screen is provided for information purposes only. FIG. 21 shows a subject the bids made for project TZ 021 since the subject's criterion was for an manual award based on price the screen allows a subject to selected a translator by clicking on the project ID. [0093] The clearinghouse may provide a credential check service for the subjects to preview information regarding the translators. Subjects can review such information as evaluations given by other subjects for each job performance the translator has performed, and general comments can be stored regarding the translator. [0094] Once a translator has been selected for a given project, he may use a pre-translation memory stored on in the translation database to pre-translate the document. The royalty tracking module can be used to allocate credits of royalties for the recycled translation units to the source translator of the translation units. If the translator of a new project uses existing translation units, creators of any such reused translator units may get credit or royalty for the use of their translation units. After the translator is finished, the translator will transmit (post) the translated file to the project coordination module and the clearinghouse will, in turn, notify the subject that the work is complete. As illustrated in FIG. 17 , the subject may preview the work before authorizing payment. If the subject is dissatisfied with the translation, he may request that the translation be corrected. The project coordination module or the royalty tracking module may maintain financial records for both the translators (operators) and the oraganizations (subjects) and periodically send the translators payment both for original translation work as well as royalties earned through the reuse of the stored translation units. The subjects may pay invoices directly using either credit cards or electronic cash payments to the clearinghouse or the financial, institution. [0095] FIGS. 4A-C , 5 and 15 - 20 show various screens for a translation embodiment that may provide information to the workflow management users. FIG. 4 A illustrates a project description screen for project TZ 001 that an operator may review before submitting an Offer Form depicted in FIG. 4B . The screen in FIG. 4A provides information such as, file name ( 402 ), source language ( 404 ), target language ( 406 ), subject matter ( 408 ), total number of words ( 410 ), the number of TUs ( 412 ), the number of TUs recycled ( 414 ), total number of new words ( 416 ), end of bidding date ( 418 ), delivery date ( 420 ), maximum price ( 422 ), award criterion ( 424 ), award decision ( 426 ), maximum number of bids ( 428 ), status ( 430 ) and best offer ( 432 ). A user may review a project's activities by accessing a Transaction History Screen illustrated in FIG. 4C . This screen provides information about the activity or action, who performed the action and when it was performed. [0096] FIG. 5 illustrates the Translator's Home Page where a translator may access information such as, the number of projects translated ( 502 ), the number of projects a translator is assigned ( 504 ), the number bid invitations ( 506 ), the total amount of recycled translation units the translator has used to complete his projects ( 508 ), the total number of translation units the translator owns ( 510 ), the number of translation units owned by the translator reused by other translators ( 512 ), the total amount of royalties earned for recycled translation units ( 514 ), the operator's current balance ( 516 ), and the number of projects awarded to the translator since his last visit to the clearinghouse site ( 518 ). [0097] FIG. 15 illustrates a screen, Subject's Home Page, where a subject may access information such as, the number of projects translated ( 1502 ), the number of projects in progress ( 1504 ), the number of projects waiting to be awarded ( 1506 ), the total amount of translation units in a subject's projects ( 1508 ), the total number of translation units that have been recycled ( 1510 ), the number of recycled words, the estimated savings at an average price/word ( 1514 ), the subject's current balance ( 1516 ), the number of projects finished and waiting to be downloaded ( 1518 ). [0098] FIG. 16 illustrates the Translation Bidding Pool. Projects that are currently open for bid may be previewed by the users using this screen, which provides information, such as, project ID ( 1602 ), source language ( 1604 ), target language ( 1606 ), subject matter ( 1608 ), total number of words ( 1610 ), number of TUs ( 1612 ), number of TUs recycled ( 1614 ), end of bidding date ( 1616 ), delivery date ( 1618 ), award criterion ( 1620 ), best offer ( 1622 ), status ( 1624 ), etc. The operators may click on the Project ID to preview a selection of the document before placing a bid. [0099] FIGS. 17 , 18 A and 18 B illustrate views that may be provided to the users for Projects in Progress. These views provide the users with information such as, the translator's/subject's name, project ID, file name, start bidding date, award date, delivery date, cycle, new delivery, status, next action, etc. The subject can see the translator assigned to a project, when it is due for delivery, etc. The translator may accept a project by clicking on Download in the Next Action field (note the Status will change from “Awarded” to “Translate” and Next Action will change from “Download” to “Upload”). The translator may download the project again, if needed, by clicking on the Project ID. When a operator has completed a translation, he clicks on Upload in the Next Action field to transmit the document back to the clearinghouse. After the system verifies a successful upload, the subject will be notified to receive and accept the translation. Then, the translator may be credited for his services. The project Status will change to Paid in Full. The project details will be shuffled to the Project History Screen, which provides information such as, subject's name, project ID, file name, start bidding, award date, delivery date, cycle new delivery, status service charge ( FIG. 22 ). [0100] Once the translation project has been completed, a subject may confirm acceptance by clicking on Accept in the Next Action field ( FIG. 17 ). The Status will change from “Uploaded” to “Paid in Full”. If a subject does not accept the project, after reading random excerpts of the translation work, he may have three options: [0101] 1. The subject may reject the work entirely. In that case the translator may only receive 50% of the original sum. The credential module may be notified and the subject may be unable to use the translation. [0102] 2. The subject may file a Fix-It request, stating his reasons for rejecting the project and set a new Delivery Date. He may also ask for a service charge reduction. A new work cycle will be initiated. The translator may reject the fix it request. If the translator and the subject have not come to terms after three Fit-It cycles, the system may either close the project and file it as Paid in Half, or if a larger sum is at stake, may escalate the case to the arbitration board. [0103] 3. The subject may call the arbitration board immediately in cases of severe business misconduct. The board may then hear both sides and suggest a remedy. [0104] Another application of the invention may be for other non-translation (projects) work assignments. For example, a subject may need research performed relating to a specified topic, such as a patent search, medical or legal research. If the fulfillment database is checked and no previously stored resources match the new project, the project coordination module and/or bid management module may institute a bidding process by posting a request for bids or sending bid invitations to qualified researchers (operators). The bid winner (operator) may conduct a search and transmit the results of the search to the project coordination module. Then the project coordination module may transmit the results to the subject and store the results in the fulfillment database. The next time a similar request is made for a search project or work assignment on the same subject matter (or similar), the project coordination module may search the fulfillment database for the earlier results. These earlier results may be exactly what the subject is looking for in which case the results may be sent directly to the subject or the earlier results may form the basis for further research. The original researcher may receive a credit for his work. [0105] If the stored results need to be updated, the project fulfillment module may provide evaluation information to the subjects and the operators regarding “how much” of the search project may be completed by recycling a previously completed research (resources). [0106] Both Netscape Navigator and Microsoft Internet Explorer browsers as well as other browsers can view the pages because the active pages are executed on the server and delivered to the client computer as simple HTML. [0107] While the invention has been particularly shown and described with reference to a preferred embodiment thereof, it will be understood by those skilled in the art that the foregoing and other changes in form and details may be made therein without departing from the scope of the invention.

A network clearinghouse may be provided that brings together organizations (subjects) requiring outsourcing of a service and service providers (operators). The clearinghouse manages the bidding and awarding of contracts, by collecting and authorizing requests for proposals (RFPs), sending bid invitations to operators that meet the requirements of the subject, sending a notification that the contract has been awarded, and collecting payment from the subject and paying the operator.

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation application of U.S. Ser. No. 12/718,739, filed Mar. 5, 2010, now allowed, which is a divisional of U.S. Ser. No. 12/115,416, filed May 5, 2008, now U.S. Pat. No. 7,691,644, issued on Apr. 6, 2010, which is a divisional of U.S. Ser. No. 10/948,358, filed Sep. 22, 2004, now U.S. Pat. No. 7,378,285, issued on May 27, 2008, which claims priority benefit of U.S. Provisional Application No. 60/505,092, filed Sep. 22, 2003. The contents of these applications are incorporated by reference in their entirety. TECHNICAL FIELD [0002] The present invention relates generally to an assay for detecting and differentiating multiple analytes, if present, in a single fluid sample, including devices and methods therefor. BACKGROUND OF THE INVENTION [0003] The field of rapid diagnostic testing has evolved for many years to permit the detection of analytes in a variety of sample types. The use of polyclonal antibodies was followed by the use of monoclonal antibodies to generate assays with high specificity for a number of analytes, including hormones, blood cells, drugs and their metabolites, as well as the antigens of infectious agents including Strep A, Strep B, Chlamydia, HIV, RSV, influenza A and influenza B and many others. The visible signal generated by enzyme-catalyzed reactions or by the accumulation of a visible signal at the level of a test line has also resulted in rapid development of highly sensitive results. Many of the rapid immunoassay-based tests include a solid housing encasing a test strip. However, recently, immunochromatographic assays have been manufactured which do not have solid housings. Such tests, referred to as dipsticks, can be dipped directly into a tube containing a pre-determined amount of the liquid sample of interest. The extremity of the dipstick containing a sample-receiving pad is generally brought in contact with a liquid sample, and the liquid migrates up the flow path. Advantages of the dipstick format include ease of use and minimum handling, which reduces the opportunities for contamination and procedural errors, and lowers manufacturing costs. [0004] One disadvantage of current immunochromatographic dipsticks is that they can only detect the presence of a single analyte. Often these devices are limited because there is no provision to mark the location of possible multiple test lines along the flow path. In the field of chemical urinalysis, dipsticks carrying multiple pads, each specific for a urine analyte to be detected and measured, the dipstick is dipped into the urine sample, then removed from the container, blotted to eliminate excess urine, and applied against a template in order to read the results. These devices are capable of evaluating multiple analytes, but are problematic. For example, such devices increase the chances of contamination by carry-over of material from one device to another, with the consequence of potentially inaccurate results. Moreover, this format exposes the user to potential contamination via removing the strip from the urine sample, blotting it on an absorbent paper, which becomes contaminated, applying it against the template, which often is the exterior wall of the product container, thereby contaminating the product package itself. Further, as indicated, an external template is required to read results. [0005] It is recognized in a variety of fields that the use of single analyte rapid tests is often limiting, for example, because only one analyte at a time can be evaluated. The advantage of rapidity is therefore challenged by the limitation of current assays as adjuncts to the diagnosis of a disease state. For instance, the pediatric units have to make differential diagnostics of Flu A, Flu B, RSV and other upper respiratory viruses, on infants that are in need of urgent care. The availability of rapid test panels would greatly facilitate the doctors' efforts to diagnose the condition, and therefore to take the appropriate course of action faster, more easily, and at lower cost. To date, no such assay has been developed that allows the differential diagnostic of two or more analytes on a single test strip, in a minimally involving procedure. [0006] In summary, chemical urinalysis dipstick assays have been used for many years to determine the presence (or amount) of multiple analytes in a urine sample; however, the technology used to perform such assays not only has undesirable use characteristics but is not readily transferable to immunologic based assays (dipstick or lateral flow) which require flow of sample through the assay device rather than immersion of the device (in particular immersion of the test portion of the device) into a sample. For example, with respect to the use of chemical urinalysis dipsticks, the fact that they must be submerged into the urine sample, removed and blotted of excess urine then placed in physical contact (or very close proximity) with an external, typically reusable (and hence contaminable), test results panel (i.e., template) is not just undesirable but unsafe, particularly if the sample contains contagious agents such as virus or bacteria. Further, because immunologic based assays typically employ at least two, generally sequential reactions (for example a labeling followed by a capture (test) reaction), they are not amenable to submersion into a sample in the same manner as the chemical urinalysis dipsticks. Thus, there is a need in the art for devices and methods that addresses these problems in the art. The present invention addresses these and other related needs in the art. SUMMARY OF INVENTION [0007] The present invention provides analytical devices, particularly immunoassay devices, capable of determining the presence and/or amount of multiple analytes in a fluid sample, permitting more complete diagnosis or analysis of said sample. Advantageously, the present devices may be formatted as dipsticks or lateral flow devices, in either case not requiring an external test results panel for determination of test results. By positioning the multiple test and/or control zones in predetermined patterns on the test devices in accordance with the present invention, the need for an external test results panel, or even markings on a test device housing, is eliminated. By way of example, in a preferred embodiment, a single control zone is positioned between two test zones, each test zone testing for the presence or amount of a different analyte. It has heretofore been assumed that a control zone must be located downstream of a test zone in order function as control zone. However, the present inventors have discovered that such is not necessary and, rather, that one or more control zones may be employed in immunoassay devices not only to provide an indication of assay completion and/or operability but also of the relative location of one or more test lines, thereby permitting rapid differentiation of analytes within a fluid sample in a single immunoassay test device. [0008] In an embodiment of the present disclosure, a device is provided for the detection of multiple analytes in a fluid sample, which device comprises: a matrix defining an axial flow path, the matrix comprising: i) a sample receiving zone at an upstream end of the flow path that receives the fluid sample, ii) a label zone positioned within the flow path and downstream from the sample receiving zone, said label zone comprising one or more labeled reagents which are capable of binding one or more analytes to form labeled analytes and are mobilizable in the presence of fluid sample, iii) one or more test zones positioned within the flow path and downstream from the label zone, wherein each of the one or more test zones contain means which permit the restraint of a different labeled analyte in each test zone or a combination of different labeled analyte in a single test zone, and wherein restrained labeled analyte is detectable within each test zone, and iv) one or more control zones positioned within the flow path and downstream from the label zone, wherein the one or more control zones incorporate means which permit the indication of the completion of an assay. In the most frequent embodiments, the device incorporates means to restrain and thereby detect two or more different labeled analytes in a sample. Also, in frequent embodiments, the device comprises a dipstick assay device. In occasional embodiments, the device comprises two or three or more test zones and two or more control zones. [0009] The present device permits the detection of multiple analytes in a sample without reference to an external template. Moreover, frequently the device comprises a dipstick assay that lacks an external housing. In general, the analytes comprise analytes of interest and further comprise those provided herein, among others. Frequently, the present devices are useful for assaying a particular panel of analytes. Also frequently, the present devices are useful to simultaneously detect two or more different analytes in a sample. On occasion the present device and methods are useful to detect a panel of analytes of interest selected from an influenza panel (comprising test zones containing reagents capable of restraining a selection of influenza A, influenza B, respiratory syncytial virus (RSV), adenovirus, rhinovirus and/or parainfluenza virus), a panel comprising one or more of streptococcus pneumoniae, mycoplasma pneumoniae and/or Chlamydia, an HIV panel, a Lupus panel, an H. Pylori panel, a toxoplasma panel, a herpes panel, a Borrelia panel, a rubella panel, a cytomegalovirus panels, a rheumatoid arthritis panel, or an Epstein-Barr panel, among others. [0010] In one preferred aspect. each of the one or more test zones lie in fluid communication with one another. Moreover, in another aspect, the one or more test zones lie in fluid communication with one or more control zones. In a further aspect, the presently contemplated devices do not utilize one or a plurality of wells, rather a matrix defining an axial flow path is utilized. In a frequent embodiment, a device in accordance with the present disclosure contains a single sample receiving zone that lies in fluid communication with the one or more test zones. [0011] In frequent embodiments, the control zone is positioned between the one or more test zones. In occasional embodiments, the positioning of the control zone between the one or more test zones comprises positioning one control zone between two test zones. Also in occasional embodiments, the positioning of the control zone between the one or more test zones comprises multiple test zones and multiple control zones, wherein each control zone is positioned between two test zones, in an alternating arrangement. Frequently, the control zone is positioned upstream of a test zone. Also frequently, the control zone is positioned downstream of a test zone. In occasional embodiments, the control zone is positioned downstream of each or all of the one or more test zones. In another embodiment, the test and control zones are positioned in an alternating format within the flow path beginning with a test zone positioned upstream of any control zone. [0012] In one embodiment, each of the one or more test zones contain means comprising an immobilized reagent capable of specifically binding a unique analyte. Thus, in this embodiment, each of the one or more test zones contain an immobilized reagent capable of specifically binding a particular analyte, wherein each of the immobilized reagents is capable of binding a different analyte than any other immobilized reagent within another test zone in the device. These means can comprise any of a variety of specific binding pair members as described elsewhere herein. On occasion, the means which permit the restraint of a different labeled analyte in each test zone comprise an immobilized capture reagent. [0013] In one aspect, the test zones can be provided in any of a variety shapes and configurations with the limitation that each particular test zone is detectably distinguishable from other test zones, if present, and the control zone(s) in the presence of labeled analyte, if present, restrained in that test zone. In a related aspect, the control zones can be provided in any of a variety shapes and configurations with the limitation that each particular control zone is detectably distinguishable from other control zones, if present, and the test zones upon completion of an assay. [0014] In another embodiment, the label zone comprises multiple labeled reagents, wherein each of the multiple labeled reagents is capable of specifically binding a unique analyte. In occasional embodiments, the labeled reagent is a reagent capable of binding any or all of the multiple analytes, if present, in the sample. Frequently, each of the labeled reagents is detectably distinguishable from one another. Also frequently, the label component of the labeled reagent is selected from the group consisting of a chemiluminescent agent, a particulate label, a colloid label, a colorimetric agent, an energy transfer agent, an enzyme, a fluorescent agent and a radioisotope. In occasional embodiments, the labeled reagents comprise different colored labeled reagents. For example, the labeled reagent can comprise 2, 3, 4, 5, or 6 or more different colored particulate reagents. Particulate label colors comprising red, blue, black, purple, and other high-contrast colors are frequently utilized in the present embodiments. In frequent embodiments, the colored particulate label comprises a colored latex particulate label. In another frequent embodiment, the colored label comprises a Carbon, Gold or Selenium colored colloid label. On occasion, the use of different colored particulate labeled reagents allows for the detection of multiple analytes via the observation of different detectable signals (e.g., different colors) in any one or more of the one or more test zones as a result of the restraint of different labeled analyte in each test zone. In a less occasional embodiment, the labeled reagent can comprise a mixture of any of a variety of detectable labeling schemes in one device such that each analyte can become labeled by a different labeled reagent to provide a different detectable signal. [0015] In occasional embodiments, a test zone may contain one or more immobilized reagents capable of specifically binding a unique analyte, such that multiple labeled analytes may become restrained and detectible in the test zone. In this embodiment there may be multiple analytes of interest for the device, however, frequently only one of these analytes is present, if at all, at one time in the fluid sample. Thus, multiple labeled reagents are useful in this embodiment which are both analyte specific and detectably distinguishable (i.e., different colors). For example, a device of the present embodiment is capable of detecting Influenza A or influenza B antigen, if present, in a single sample. In the case of influenza A, a red-colored labeled reagent that is capable of specifically binding influenza A may be used, which would result in the development of a red-colored test zone after completion of the assay of a fluid sample containing influenza A analyte. In the case of Influenza B, a blue-colored labeled reagent that is capable of specifically binding influenza B may be used, which would result in the development of a blue-colored test zone after completion of the assay of a fluid sample containing influenza B analyte. One of skill in the art would recognize that the colors may be alternated and/or other detectibly distinguishable labeling means contemplated herein may be utilized. Frequently, such test zones can be deposited as single zones containing a mixture of capture reagents, or as adjacent zones of single capture reagents. On occasion, in the present embodiment, multiple analytes of interest are present together in the fluid sample, which then become labeled subsequent to contact with the device and restrained in the test zone. Thus, multiple labeled analytes may be restrained in a single test zone. [0016] In another embodiment, the sample receiving zone and the label zone comprise separate components in fluid-flow contact. In a frequent embodiment, the one or more test zones and the control zone are positioned within a test region. Moreover, frequently, the sample receiving zone, label zone and the test region comprise separate components in fluid-flow contact. Also frequently, the test region comprises nitrocellulose or other material suitable for immobilization of test and control reagents, and/or is laminated on a plastic backing material. On occasion, the matrix is positioned within a housing comprising a support and optionally a cover, wherein the housing contains a sample-receiving aperture and one or more observation ports. In occasional embodiments, the control zone comprises a mark that is detectable within the test region when the test region is in a moist state. In this embodiment the test region comprises a material that is opaque in a dry state and transparent in a moist state such that the mark become visible as the liquid sample moistens the test region. [0017] In a further embodiment, the device is capable of detecting influenza A and/or influenza B, if present, in a single sample. In occasional embodiments, each of the multiple analytes are selected from the group consisting of a toxin, an organic compound, a protein, a peptide, a microorganism, a bacteria, a virus, an amino acid, a nucleic acid, a carbohydrate, a hormone, a steroid, a vitamin, a drug, an antibody, and a hapten. [0018] In another further embodiment, the number of control zones is represented by the variable “n” and the number of test zones is represented by the variable “n+1,” and wherein the test zones and control zones are positioned in a series comprising an alternating format, wherein the zone arranged at the most downstream position in the series comprises a test zone. The variable “n” often refers to 2 test zones. However, on occasion, the variable “n” refers to between 2 to about 5 test zones. Thus, on occasion, 2, 3, 4, 5 or more test zones are positioned on the device. Frequently, each of the test zones permit the restraint of a different analyte. On occasion, a device is provided that is capable of detecting a number of different analytes represented by the variable “n,” wherein the number of control zones and the number of different analytes capable of being detected by the device are equal. Also on occasion, a device is provided that is capable of detecting a number of different analytes represented by the variable “n+1,” wherein the number of test zones and the number of different analytes capable of being detected by the device are equal. [0019] In frequent embodiments a device for the detection of multiple analytes in a fluid sample is provided, wherein the device comprises: a matrix defining an axial flow path, the matrix comprising: i) a sample receiving zone at an upstream end of the flow path that receives the fluid sample; ii) a label zone, within the flow path and downstream from the sample receiving zone, comprising a first and second labeled reagent, each of which specifically bind an analyte to form a labeled analyte and are mobilizable in the presence of fluid sample; and iii) a test region comprising a first test zone, a second test zone and a control zone, wherein the control zone is positioned between the first and second test zones within the flow path, wherein each of the first and second test zones contain means which permit the detection of a different analyte in each test zone, and wherein the control zone incorporates means which allow for the indication of the completion of an assay. In occasional embodiments, the first zone is positioned upstream from the control zone within the flow path and the second zone is positioned downstream from the control zone within the flow path. [0020] In another embodiment, methods are provided for the detection of one or more analytes in a fluid sample. For example, a method is provided for the detection of multiple analytes in a fluid sample, comprising: i) contacting a device of the type described above with a fluid sample suspected of containing one or more analytes, and wherein each of the one or more test zones in the device contains means which permit the restraint of a different labeled analyte or combination of labeled analytes in each test zone; and ii) detecting one or more labeled analytes restrained in the one or more test zones. Frequently the device comprises a dipstick-type device. In general, the analytes of interest comprise those provided herein, among others. Frequently, the present methods are useful for assaying a particular panel of analytes. Also frequently, the present methods are useful to simultaneously detect two or more different analytes in a sample. Commonly the present devices and methods are utilized to diagnose a medical condition. Also commonly, the present devices and methods aid in guiding therapeutic decisions. On occasion, the present method steps may be practiced at different locations, and by different entities. [0021] These and other features and advantages of the present invention will be apparent from the following detailed description, examples and claims. BRIEF DESCRIPTION OF THE DRAWINGS [0022] FIG. 1(A-J) depicts various example configurations of the test and control zones within the presently contemplated devices. The arrow in each Figure indicates the general direction of fluid sample flow after initial contact with the device. The boxes containing vertical lines and/or the diagonal lines depict control zones, and the boxes containing crosshatched lines depict test zones. FIG. 1 (A-J) further depicts the sample receiving zone [1], the label zone [2] and the test region [3]. The present devices are not intended to be limited to the aspects indicated in the depicted embodiments, other configurations are contemplated. Moreover, the depicted aspects are not necessarily presented to scale. [0023] FIG. 2 is a graph depicting the ratio of test zone and control zone signals for different volumes of sample in exemplary devices. DETAILED DESCRIPTION OF THE INVENTION [0024] For clarity of disclosure, and not by way of limitation, the detailed description of the invention is divided into the subsections that follow. A. DEFINITIONS [0025] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as is commonly understood by one of ordinary skill in the art to which this invention belongs. All patents, applications, published applications and other publications referred to herein are incorporated by reference in their entirety. If a definition set forth in this section is contrary to or otherwise inconsistent with a definition set forth in the patents, applications, published applications and other publications that are herein incorporated by reference, the definition set forth in this section prevails over the definition that is incorporated herein by reference. [0026] As used herein, “a” or “an” means “at least one” or “one or more.” The use of the phrase “one or more” herein does not alter this intended meaning for the terms “a” or “an.” [0027] As used herein, “disease or disorder” refers to a pathological condition in an organism resulting from, e.g., infection or genetic defect, and characterized by identifiable symptoms. [0028] As used herein the term “sample” refers to anything which may contain an analyte for which an analyte assay is desired. The sample may be a biological sample, such as a biological fluid or a biological tissue. Examples of biological fluids include urine, blood, plasma, serum, saliva, semen, stool, sputum, cerebral spinal fluid, tears, mucus, amniotic fluid or the like. Biological tissues are aggregate of cells, usually of a particular kind together with their intercellular substance that form one of the structural materials of a human, animal, plant, bacterial, fungal or viral structure, including connective, epithelium, muscle and nerve tissues. Examples of biological tissues also include organs, tumors, lymph nodes, arteries and individual cell(s). [0029] “Fluid sample” refers to a material suspected of containing the analyte(s) of interest, which material has sufficient fluidity to flow through an immunoassay device in accordance herewith. The fluid sample can be used as obtained directly from the source or following a pretreatment so as to modify its character. Such samples can include human, animal or man-made samples. The sample can be prepared in any convenient medium which does not interfere with the assay. Typically, the sample is an aqueous solution or biological fluid as described in more detail below. [0030] The fluid sample can be derived from any source, such as a physiological fluid, including blood, serum, plasma, saliva, sputum, ocular lens fluid, sweat, urine, milk, ascites fluid, mucous, synovial fluid, peritoneal fluid, transdermal exudates, pharyngeal exudates, bronchoalveolar lavage, tracheal aspirations, cerebrospinal fluid, semen, cervical mucus, vaginal or urethral secretions, amniotic fluid, and the like. Herein, fluid homogenates of cellular tissues such as, for example, hair, skin and nail scrapings, meat extracts and skins of fruits and nuts are also considered biological fluids. Pretreatment may involve preparing plasma from blood, diluting viscous fluids, and the like. Methods of treatment can involve filtration, distillation, separation, concentration, inactivation of interfering components, and the addition of reagents. Besides physiological fluids, other samples can be used such as water, food products, soil extracts, and the like for the performance of industrial, environmental, or food production assays as well as diagnostic assays. In addition, a solid material suspected of containing the analyte can be used as the test sample once it is modified to form a liquid medium or to release the analyte. The selection and pretreatment of biological, industrial, and environmental samples prior to testing is well known in the art and need not be described further. [0031] As used herein, the term “specifically binds” refers to the binding specificity of a specific binding pair. “Specific pair binding member” refers to a member of a specific binding pair, i.e., two different molecules wherein one of the molecules specifically binds with the second molecule through chemical or physical means. The two molecules are related in the sense that their binding with each other is such that they are capable of distinguishing their binding partner from other assay constituents having similar characteristics. The members of the specific binding pair are referred to as ligand and receptor (antiligand), sbp member and sbp partner, and the like. A molecule may also be a sbp member for an aggregation of molecules; for example an antibody raised against an immune complex of a second antibody and its corresponding antigen may be considered to be an sbp member for the immune complex. [0032] In addition to antigen and antibody specific binding pair members, other specific binding pairs include, as examples without limitation, biotin and avidin, carbohydrates and lectins, complementary nucleotide sequences, complementary peptide sequences, effector and receptor molecules, enzyme cofactors and enzymes, enzyme inhibitors and enzymes, a peptide sequence and an antibody specific for the sequence or the entire protein, polymeric acids and bases, dyes and protein binders, peptides and specific protein binders (e.g., ribonuclease, S-peptide and ribonuclease S-protein), metals and their chelators, and the like. Furthermore, specific binding pairs can include members that are analogs of the original specific binding member, for example an analyte-analog or a specific binding member made by recombinant techniques or molecular engineering. [0033] An sbp member is analogous to another sbp member if they are both capable of binding to another identical complementary sbp member. Such an sbp member may, for example, be either a ligand or a receptor that has been modified by the replacement of at least one hydrogen atom by a group to provide, for example, a labeled ligand or labeled receptor. The sbp members can be analogous to or complementary to the analyte or to an sbp member that is complementary to the analyte. [0034] If the specific binding member is an immunoreactant it can be, for example, an antibody, antigen, hapten, or complex thereof. If an antibody is used, it can be a monoclonal or polyclonal antibody, a recombinant protein or antibody, a chimeric antibody, a mixture(s) or fragment(s) thereof, as well as a mixture of an antibody and other specific binding members. The details of the preparation of such antibodies and their suitability for use as specific binding members are known to those skilled in the art. [0035] “Antigen” shall mean any compound capable of binding to an antibody, or against which antibodies can be raised. [0036] “Antibody” refers to a polypeptide substantially encoded by an immunoglobulin gene or immunoglobulin genes, or fragments thereof. The recognized immunoglobulin genes include the kappa, lambda, alpha, gamma, delta, epsilon, and mu constant regions, as well as myriad immunoglobulin variable region genes. Light chains are classified as either kappa or lambda. Heavy chains are classified as gamma, mu, alpha, delta, or epsilon, which in turn define the immunoglobulin classes, IgG, IgM, IgA, IgD, and IgE, respectively. Typically, an antibody is an immunoglobulin having an area on its surface or in a cavity that specifically binds to and is thereby defined as complementary with a particular spatial and polar organization of another molecule. The antibody can be polyclonal or monoclonal. Antibodies may include a complete immunoglobulin or fragments thereof. Fragments thereof may include Fab, Fv and F(ab′)2, Fab′, and the like. Antibodies may also include chimeric antibodies or fragment thereof made by recombinant methods. [0037] “Analyte” refers to the compound or composition to be detected or measured and which has at least one epitope or binding site. The analyte can be any substance for which there exists a naturally occurring analyte specific binding member or for which an analyte-specific binding member can be prepared. e.g., carbohydrate and lectin, hormone and receptor, complementary nucleic acids, and the like. Further, possible analytes include virtually any compound, composition, aggregation, or other substance which may be immunologically detected. That is, the analyte, or portion thereof, will be antigenic or haptenic having at least one determinant site, or will be a member of a naturally occurring binding pair. [0038] Analytes include, but are not limited to, toxins, organic compounds, proteins, peptides, microorganisms, bacteria, viruses, amino acids, nucleic acids, carbohydrates, hormones, steroids, vitamins, drugs (including those administered for therapeutic purposes as well as those administered for illicit purposes), pollutants, pesticides, and metabolites of or antibodies to any of the above substances. The term analyte also includes any antigenic substances, haptens, antibodies, macromolecules, and combinations thereof. A non-exhaustive list of exemplary analytes is set forth in U.S. Pat. No. 4,366,241, at column 19, line 7 through column 26, line 42, the disclosure of which is incorporated herein by reference. Further descriptions and listings of representative analytes are found in U.S. Pat. Nos. 4,299,916; 4,275,149; and 4,806,311, all incorporated herein by reference. [0039] “Labeled reagent” refers to a substance comprising a detectable label attached with a specific binding member. The attachment may be covalent or non-covalent binding, but the method of attachment is not critical to the present invention. The label allows the label reagent to produce a detectable signal that is related to the presence of analyte in the fluid sample. The specific binding member component of the label reagent is selected to directly bind to the analyte or to indirectly bind the analyte by means of an ancillary specific binding member, which is described in greater detail hereinafter. The label reagent can be incorporated into the test device at a site upstream from the capture zone, it can be combined with the fluid sample to form a fluid solution, it can be added to the test device separately from the test sample, or it can be predeposited or reversibly immobilized at the capture zone. In addition, the specific binding member may be labeled before or during the performance of the assay by means of a suitable attachment method. [0040] “Label” refers to any substance which is capable of producing a signal that is detectable by visual or instrumental means. Various labels suitable for use in the present invention include labels which produce signals through either chemical or physical means. Such labels can include enzymes and substrates, chromogens, catalysts, fluorescent compounds, chemiluminescent compounds, and radioactive labels. Other suitable labels include particulate labels such as colloidal metallic particles such as gold, colloidal non-metallic particles such as selenium or tellurium, dyed or colored particles such as a dyed plastic or a stained microorganism, organic polymer latex particles and liposomes, colored beads, polymer microcapsules, sacs, erythrocytes, erythrocyte ghosts, or other vesicles containing directly visible substances, and the like. Typically, a visually detectable label is used as the label component of the label reagent, thereby providing for the direct visual or instrumental readout of the presence or amount of the analyte in the test sample without the need for additional signal producing components at the detection sites. [0041] The selection of a particular label is not critical to the present invention, but the label will be capable of generating a detectable signal either by itself, or be instrumentally detectable, or be detectable in conjunction with one or more additional signal producing components, such as an enzyme/substrate signal producing system. A variety of different label reagents can be formed by varying either the label or the specific binding member component of the label reagent; it will be appreciated by one skilled in the art that the choice involves consideration of the analyte to be detected and the desired means of detection. As discussed below, a label may also be incorporated used in a control system for the assay. [0042] For example, one or more signal producing components can be reacted with the label to generate a detectable signal. If the label is an enzyme, then amplification of the detectable signal is obtained by reacting the enzyme with one or more substrates or additional enzymes and substrates to produce a detectable reaction product. [0043] In an alternative signal producing system, the label can be a fluorescent compound where no enzymatic manipulation of the label is required to produce the detectable signal. Fluorescent molecules include, for example, fluorescein, phycobiliprotein, rhodamine and their derivatives and analogs are suitable for use as labels in such a system. [0044] The use of dyes for staining biological materials, such as proteins, carbohydrates, nucleic acids, and whole organisms is documented in the literature. It is known that certain dyes stain particular materials preferentially based on compatible chemistries of dye and ligand. For example, Coomassie Blue and Methylene Blue for proteins, periodic acid-Schiff s reagent for carbohydrates, Crystal Violet, Safranin O, and Trypan Blue for whole cell stains, ethidium bromide and Acridine Orange for nucleic acid staining, and fluorescent stains such as rhodamine and Calcofluor White for detection by fluorescent microscopy. Further examples of labels can be found in, at least, U.S. Pat. Nos. 4,695,554; 4,863,875; 4,373,932; and 4,366,241, all incorporated herein by reference. [0045] “Signal producing component” refers to any substance capable of reacting with another assay reagent or with the analyte to produce a reaction product or signal that indicates the presence of the analyte and that is detectable by visual or instrumental means. “Signal production system”, as used herein, refers to the group of assay reagents that are needed to produce the desired reaction product or signal. [0046] “Observable signal” as used herein refers to a signal produced in the claimed devices and methods that is detectable by visual inspection. Without limitation, the type of signal produced depends on the label reagents and marks used (described herein). Generally, observable signals indicating the presence or absence of an analyte in a sample may be evident of their own accord, e.g., plus or minus signs or particularly shaped symbols, or may be evident through the comparison with a panel such as a color indicator panel. [0047] “Axial flow” as used herein refers to lateral, vertical or transverse flow through a particular matrix or material comprising one or more test and/or control zones. The type of flow contemplated in a particular device, assay or method varies according to the structure of the device. Without being bound by theory, lateral, vertical or transverse flow may refer to flow of a fluid sample from the point of fluid contact on one end or side of a particular matrix (the upstream or proximal end) to an area downstream (or distal) of this contact. The downstream area may be on the same side or on the opposite side of the matrix from the point of fluid contact. For example, in vertical flow devices of the present invention, axial flow may progress vertically from and through a first member (top to bottom) to a second member and from there on to an absorbent medium. By way of further example, and as will be appreciated by those of skill in the art, in a vertical flow device configured, for example, as a dipstick, a fluid sample may flow literally up the device, in which case however, the point of first contact of the fluid sample to the device is nonetheless considered the upstream (i.e., proximal) end and the point of termination of flow the downstream (i.e., distal) end. [0048] “Absorbent material” as used herein refers to material used in vertical flow devices and assays that allows and promotes sample flow through the first and second members. Such materials may be as described in, e.g., U.S. Pat. No. 4,632,901, such as, for example, fibrous materials such as cellulose acetate fibers, cellulose or cellulose derivatives, polyester, or polyolefin. Generally, the absorbent material, as used herein, should maintain direct or intimate contact with the second member in order to promote fluid flow therethrough. Contemplated absorbent materials having fluid absorptive qualities are generally compressible and may be compressed in devices of the present invention to ensure contact with the second member or positive control element. [0049] As used herein the phrase “mark that is detectable within the test region when the test region is in a moist state” refers to the type of mark described, for example in U.S. patent application Ser. No. 09/950,366, filed, Sep. 10, 2001, currently pending and published as U.S. Patent Application Publication No. 20030049167, and 10/241,822, filed Sep. 10, 2002, currently pending and published as U.S. Patent Application Publication No. 20030157699. [0050] As used herein the terms “upstream” and “downstream” refer to the direction of fluid sample flow subsequent to contact of the fluid sample with a representative device of the present disclosure, wherein, under normal operating conditions, the fluid sample flow direction runs from an upstream position to a downstream position. For example, when fluid sample is initially contacted with the sample receiving zone, the fluid sample then flows downstream through the label zone and so forth. [0051] As used herein the phrase “completion of an assay” refers to axial flow of applied liquid sample suspected of containing one or more analytes through a representative device, downstream of at least one test zone and at least one control zone. Thus, as used herein multiple assays could be completed in a single device which comprises multiple pairs of alternating test and control zones. More commonly, the phrase completion of assay refers to axial flow of applied liquid sample suspected of containing one or more analytes through a representative device, downstream of all test and control zones on or in the device. B. TEST DEVICES [0052] The present description provides for the development and use of single or multiple control zones in a single immunoassay device that are positioned in a predetermined manner relative to individual test zones thereby allowing easy identification of each of the one or more analytes of interest tested for in the device. The present description further provides for the making of control zones of various shapes, physical or chemical identities, and colors. In part, the use of such control zones allows for immunoassay devices, particularly including dipsticks, that are easy to use, and allow for the identification of multiple analytes during a single assay procedure. [0053] The present description further provides means to build a rapid, multi-analyte assay, which is needed in many fields of environmental monitoring, medicine, particularly in the field of infectious disease. For example, contemplated devices include those useful for the differential diagnosis of Flu A or Flu B, which may result in different treatments, or the differential diagnosis of Flu A. Flu B, and/or RSV in one step. Such devices permit the use of a single sample for assaying multiple analytes at once, and beneficially allows for a considerable reduction of the hands-on time and duration of the diagnostic process for the benefit of the doctor, or user in general. [0054] A variety of analytes may be assayed utilizing devices and methods of the present disclosure. In a particular device useful for assaying for one or more analytes of interest in a sample, the collection of analytes of interest may be referred to as a panel. For example, a panel may comprise any combination (or all of) of influenza A, influenza B, respiratory syncytial virus (RSV), adenovirus, and parainfluenza virus. Another panel may comprise testing for a selection of one or more of upper respiratory infection including, for example, streptococcus pneumoniae, mycoplasma and/or pneumoniae. Yet another panel can be devised for the diagnosis of sexually transmitted disease including, for example, Chlamydia, Trichomonas and/or Gonorrhea. [0055] On occasion a panel may optionally include a variety of other analytes of interest, including SARS-associated coronavirus, influenza C; a hepatitis panel comprising a selection of hepatitis B surface Ag or Ab, hepatitis B core Ab, hepatitis A virus Ab, and hepatitis C virus; a phospholipids panel comprising a selection of Anticardiolipin Abs (IgG, IgA, and IgM Isotypes); an arthritis panel comprising a selection of rheumatoid factor, antinuclear antibodies, and Uric Acid; an Epstein Barr panel comprising a selection of Epstein Barr Nuclear Ag, Epstein Barr Viral Capsid Ag, and Epstein Barr Virus, Early Antigen; other panels include HIV panels, Lupus panels, H. Pylori panels, toxoplasma panels, herpes panels, Borrelia panels, rubella panels, cytomegalovirus panels, and many others. One of skill in art would understand that a variety of panels may be assayed via the immunoassays described herein. See, e.g., C URRENT P ROTOCOLS IN I MMUNOLOGY (Coligan, John E. et. al., eds. 1999). [0056] Other fields of interest include the diagnosis of veterinary diseases, analysis of meat, poultry, fish for bacterial contamination, inspection of food plants, restaurants, hospitals and other public facilities, analysis of environmental samples including water for beach, lakes or swimming pool contamination. Analytes detected by these tests include viral and bacterial antigens as well as chemicals including, for example, lead, pesticides, hormones, drugs and their metabolites, hydrocarbons and all kinds of organic or inorganic compounds. [0057] The present disclosure provides a test device, particularly immunoassay devices, for determining the presence or absence of multiple analytes in a fluid sample. In general, a test device of the present disclosure includes a matrix defining an axial flow path. Typically, the matrix further includes a sample receiving zone, a label zone, a test zone and a control zone. In frequent embodiments, a test region comprises the test and control zones. In a related embodiment, the matrix further includes an absorbent zone disposed downstream of the test region. Moreover, in preferred embodiments, the test region, which comprises the test and control zones, is observable. [0058] Numerous analytical devices known to those of skill in the art may be adapted in accordance with the present invention, to detect multiple analytes. By way of example, dipstick, lateral flow and flow-through devices, particularly those that are immunoassays, may be modified in accordance herewith in order to detect and distinguish multiple analytes. Exemplary lateral flow devices include those described in U.S. Pat. Nos. 4,818,677, 4,943,522, 5,096,837 (RE 35,306), 5,096,837, 5,118,428, 5,118,630, 5,221,616, 5,223,220, 5,225,328, 5,415,994, 5,434,057, 5,521,102, 5,536,646, 5,541,069, 5,686,315, 5,763,262, 5,766,961, 5,770,460, 5,773,234, 5,786,220, 5,804,452, 5,814,455, 5,939,331, 6,306,642. Other lateral flow devices that may be modified for use in distinguishable detection of multiple analytes in a fluid sample include U.S. Pat. Nos. 4,703,017, 6,187,598, 6,352,862, 6,485,982, 6,534,320 and 6,767,714. Exemplary dipstick devices include those described in U.S. Pat. Nos. 4,235,601, 5,559,041, 5,712,172 and 6,790,611. It will be appreciated by those of skill in the art that the aforementioned patents may and frequently do disclose more than one assay configuration and are likewise referred to herein for such additional disclosures. Advantageously, the improvements described are applicable to various assay, especially immunoassay, configurations. [0059] In a frequent embodiment, the sample receiving zone accepts a fluid sample that may contain analytes of interest. In another embodiment, the sample receiving zone is dipped into a fluid sample. A label zone is located downstream of the sample receiving zone, and contains one or more mobile label reagents that recognize, or are capable of binding the analytes of interest. Further, a test region is disposed downstream from the label zone, and contains test and control zones. The test zone(s) generally contain means which permit the restraint of a particular analyte of interest in each test zone. Frequently, the means included in the test zone(s) comprise an immobilized capture reagent that binds to the analyte of interest. Generally the immobilized capture reagent specifically binds to the analyte of interest. Although, on occasion, the means which permit the restraint of a particular analyte of interest in each test zone comprise another physical, chemical or immunological means for specifically restraining an analyte of interest. Thus, as the fluid sample flows along the matrix, the analyte of interest will first bind with a mobilizable label reagent in the label zone, and then become restrained in the test zone. In occasional embodiments, the test region is comprised of a material that is opaque in a dry state and transparent in a moist state. Thus, when a control zone comprising a mark on the device is utilized, this mark is positioned about the test region such that it becomes visible within the test region when the test region is in a moist state. [0060] In another preferred embodiment, the fluid sample flows along a flow path running from the sample receiving zone (upstream), through the label zone, and then to the test and control zones (together comprised in a test region) (downstream). Optionally, the fluid sample may thereafter continue to the absorbent zone. [0061] In one embodiment, the sample receiving zone is comprised of an absorbent application pad. Suitable materials for manufacturing absorbent application pads include, but are not limited to, hydrophilic polyethylene materials or pads, acrylic fiber, glass fiber, filter paper or pads, desiccated paper, paper pulp, fabric, and the like. For example, the sample receiving zone may be comprised of a material such as a nonwoven spunlaced acrylic fiber, i.e., New Merge (available from DuPont) or HDK material (available from HDK Industries, Inc.). In a related embodiment, the sample receiving zone is constructed from any material that is capable of absorbing water. [0062] In another embodiment, the sample receiving zone is comprised of any material from which the fluid sample can pass to the label zone. Further, the absorbent application pad can be constructed to act as a filter for cellular components, hormones, particulate, and other certain substances that may occur in the fluid sample. Application pad materials suitable for use by the present invention also include those application pad materials disclosed in U.S. Pat. No. 5,075,078, incorporated herein by reference. [0063] The functions of the sample receiving zone may include, for example: pH control/modification and/or specific gravity control/modification of the sample applied, removal or alteration of components of the sample which may interfere or cause non-specific binding in the assay, or to direct and control sample flow to the test region. The filtering aspect allows an analyte of interest to migrate through the device in a controlled fashion with few, if any, interfering substances. The filtering aspect, if present, often provides for a test having a higher probability of success and accuracy. In another embodiment, the sample receiving zone may also incorporate reagents useful to avoid cross-reactivity with non-target analytes that may exist in a sample and/or to condition the sample; depending on the particular embodiment, these reagents may include non-hCG blockers, anti-RBC reagents, Tris-based buffers, EDTA, among others. When the use of whole blood is contemplated, anti-RBC reagents are frequently utilized. In yet another embodiment, the sample receiving zone may incorporate other reagents such as ancillary specific binding members, fluid sample pretreatment reagents, and signal producing reagents. [0064] In a further embodiment, the sample receiving zone is comprised of an additional sample application member (e.g., a wick). Thus, in one aspect, the sample receiving zone can comprise a sample application pad as well as a sample application member. Often the sample application member is comprised of a material that readily absorbs any of a variety of fluid samples contemplated herein, and remains robust in physical form. Frequently, the sample application member is comprised of a material such as white bonded polyester fiber. Moreover, the sample application member, if present, is positioned in fluid-flow contact with a sample application pad. This fluid flow contact can comprise an overlapping, abutting or interlaced type of contact. In occasional embodiments, the sample application member may be treated with a hydrophilic finishing. Often the sample application member, if present, may contain similar reagents and be comprised of similar materials to those utilized in exemplary sample application pads. [0065] In another embodiment, the test device is configured to perform an immunological analysis process. In yet another embodiment, the liquid transport along the matrix is based upon capillary action. In a further embodiment, the liquid transport along the matrix is based on non-bibulous lateral flow, wherein all of the dissolved or dispersed components of the liquid sample are carried at substantially equal rates and with relatively unimpaired flow laterally through the matrix, as opposed to preferential retention of one or more components as would occur, e.g., in materials that interact, chemically, physically, ionically or otherwise with one or more components. See for example, U.S. Pat. No. 4,943,522, hereby incorporated by reference in its entirety. [0066] One purpose of the label zone is to maintain label reagents and control reagents in a stable state and to facilitate their rapid and effective solubilization, mobilization and specific reaction with analytes of interest potentially present in a fluid sample. [0067] In one embodiment, the label zone is comprised of a porous material such as high density polyethylene sheet material manufactured by Porex Technologies Corp. of Fairburn, Ga., USA. The sheet material has an open pore structure with a typical density, at 40% void volume, of 0.57 gm/cc and an average pore diameter of 1 to 250 micrometers, the average generally being from 3 to 100 micrometers. In another embodiment, the label zone is comprised of a porous material such as a nonwoven spunlaced acrylic fiber (similar to the sample receiving zone), e.g., New Merge or HDK material. Often, the porous material may be backed by, or laminated upon, a generally water impervious layer, e.g., Mylar. When employed, the backing is generally fastened to the matrix by an adhesive (e.g., 3M 444 double-sided adhesive tape). Typically, a water impervious backing is used for membranes of low thickness. A wide variety of polymers may be used provided that they do not bind nonspecifically to the assay components and do not interfere with flow of the fluid sample. Illustrative polymers include polyethylene, polypropylene, polystyrene and the like. On occasion, the matrix may be self-supporting. Other membranes amenable to non-bibulous flow, such as polyvinyl chloride, polyvinyl acetate, copolymers of vinyl acetate and vinyl chloride, polyamide, polycarbonate, polystyrene, and the like, can also be used. In yet another embodiment, the label zone is comprised of a material such as untreated paper, cellulose blends, nitrocellulose, polyester, an acrylonitrile copolymer, and the like. The label zone may be constructed to provide either bibulous or non-bibulous flow, frequently the flow type is similar or identical to that provided in at least a portion of the sample receiving zone. In a frequent embodiment, the label zone is comprised of a nonwoven fabric such as Rayon or glass fiber. Other label zone materials suitable for use by the present invention include those chromatographic materials disclosed in U.S. Pat. No. 5,075,078, which is herein incorporated by reference. [0068] In a frequent embodiment, the label zone material is treated with labeled solution that includes material-blocking and label-stabilizing agents. Blocking agents include bovine serum albumin (BSA), methylated BSA, casein, nonfat dry milk. Stabilizing agents are readily available and well known in the art, and may be used, for example, to stabilize labeled reagents. In frequent embodiments, employment of the selected blocking and stabilizing agents together with labeled reagent in the labeling zone followed by the drying of the blocking and stabilizing agents (e.g., a freeze-drying or forced air heat drying process) is utilized to attain improved performance of the device. [0069] The label zone generally contains a labeled reagent, often comprising one or more labeled reagents. In many of the presently contemplated embodiments, multiple types of labeled reagents are incorporated in the label zone such that they may permeate together with a fluid sample contacted with the device. These multiple types of labeled reagent can be analyte specific or control reagents and may have different detectable characteristics (e.g., different colors) such that one labeled reagent can be differentiated from another labeled reagent if utilized in the same device. As the labeled reagents are frequently bound to a specific analyte of interest subsequent to fluid sample flow through the label zone, differential detection of labeled reagents having different specificities (including analyte specific and control labeled reagents) may be a desirable attribute. However, frequently, the ability to differentially detect the labeled reagents having different specificities based on the label component alone is not necessary due to the presence of defined test and control zones in the device, which allow for the accumulation of labeled reagent in designated zones. [0070] In one embodiment, a nonparticulate labeling scheme is contemplated. In these devices, a label which is a dyed antibody-enzyme complex is utilized. This dyed antibody-enzyme complex can be prepared by polymerizing an antibody-enzyme conjugate in the presence of enzyme substrate and surfactant. See, e.g., WO 9401775. Generally, the label zone contains detectible moieties comprising enzyme-antibody conjugate, particulate labeled reagents, or dye labeled reagents, metal sol labeled reagents, etc., or moieties which may or may not be visible, but which can be detected if accumulated in the test and/or control zones. The detectible moieties can be dyes or dyed polymers which are visible when present in sufficient quantity, or can be, and are preferred to be particles such as dyed or colored latex beads, liposomes, metallic or non-metallic colloids, organic, inorganic or dye solutions, dyed or colored cells or organisms, red blood cells and the like. The detectible moieties used in the assay provide the means for detection of the nature of and/or quantity of result, and accordingly, their localization in the test zones may be a function of the analyte in the sample. In general, this can be accomplished by coupling the detectible moieties to a ligand which binds specifically to an analyte of interest, or which competes with an analyte of interest for the means which permit the restraint of an analyte of interest positioned in the test zone(s). In the first approach, the detectible moieties are coupled to a specific binding partner which binds the analyte specifically. For example, if the analyte is an antigen, an antibody specific for this antigen may be used; immunologically reactive fragments of the antibody, such as F(ab′)2, Fab or Fab′ can also be used. These ligands coupled to the detectible moieties then bind to an analyte of interest if present in the sample as the sample passes through the labeling zone and are carried into the test region by the fluid flow through the device. When the labeled analyte reaches the capture zone, it is restrained by a restraint reagent which is analyte-specific, label/detectible moiety-specific, or ligand-specific, such as an antibody or another member of a specific binding pair. In the second approach, the conjugate or particulate moieties are coupled to a ligand which is competitive with analyte for an analyte-specific restraint reagent in a test zone. Both the analyte from the sample and the competitor bound to the detectible moieties progress with the flow of the fluid sample to the test region. Both analyte and its competitor then react with the analyte-specific restraint reagent positioned in a test zone. The unlabeled analyte thus is able to reduce the quantity of competitor-conjugated detectible moieties which are retained in the test zone. This reduction in retention of the detectible moieties becomes a measure of the analyte in the sample. [0071] The labeling zone of immunoassay devices of the present invention may also include control-type reagents. These labeled control reagents often comprise detectible moieties that will not become restrained in the test zones and that are carried through to the test region and control zone(s) by fluid sample flow through the device. In a frequent embodiment, these detectible moieties are coupled to a member of a specific binding pair to form a control conjugate which can than be restrained in a separate control zone of the test region by a corresponding member of the specific binding pair to verify that the flow of liquid is as expected. The visible moieties used in the labeled control reagents may be the same or different color, or of the same or different type, as those used in the analyte of interest specific labeled reagents. If different colors are used, ease of observing the results may be enhanced. Generally, as used herein, the labeled control reagents are also referred to herein together with analyte specific labeled reagents or labeled test reagents as “labeled reagent(s).” [0072] The test region is frequently comprised of a material such as cellulose, nitrocellulose, nylon, or hydrophilic polyvinylidene difluoride (PVDF). Hydrophilic polyvinylidene difluoride (PVDF) (available from Millipore, Billerica, Mass.). The term “nitrocellulose” is meant any nitric acid ester of cellulose. Thus suitable materials may include nitrocellulose in combination with carboxylic acid esters of cellulose. The pore size of nitrocellulose membranes may vary widely, but is frequently within about 5 to 20 microns, preferably about 8 to 15 microns. However, other materials are contemplated which are known to those skilled in the art. In a frequent embodiment, the test region comprises a nitrocellulose web assembly made of Millipore nitrocellulose roll laminated to a clear Mylar backing. In another embodiment, the test region is made of nylon. In less occasional embodiment, the test region is comprised of a material that can immobilize latex or other particles which carry a second reagent capable of binding specifically to an analyte, thereby defining a test zone, for example, compressed nylon powder, or fiber glass. In an occasional embodiment, the test region is comprised of a material that is opaque when in a dry state, and transparent when in a moistened state. Preferably, the test and control zones may be constructed from any of the materials as listed above for the test region. Often the test and control zones form defined components of the test region. In a particularly preferred embodiment, the test and control zones are comprised of the same material as the test region. Frequently, the term “test region” is utilized herein to refer to a region in/on a device that comprises at least the test and control zones. To provide non-bibulous flow, these materials may be and preferably are treated with blocking agents that can block the forces which account for the bibulous nature of bibulous membranes. Suitable blocking agents include bovine serum albumin, methylated bovine serum albumin, whole animal serum, casein, and non-fat dry milk, as well as a number of detergents and polymers, e.g., PEG, PVA and the like. Preferably the interfering sites on the untreated bibulous membranes are completely blocked with the blocking agent to permit non-bibulous flow there through. As indicated herein, the present disclosure envisages a test device with multiple test and control zones. [0073] The test region generally includes a control zone that is useful to verify that the sample flow is as expected. Each of the control zones comprise a spatially distinct region that often includes an immobilized member of a specific binding pair which reacts with a labeled control reagent. In an occasional embodiment, the procedural control zone contains an authentic sample of the analyte of interest, or a fragment thereof. In this embodiment, one type of labeled reagent can be utilized, wherein fluid sample transports the labeled reagent to the test and control zones; and the labeled reagent not bound to an analyte of interest will then bind to the authentic sample of the analyte of interest positioned in the control zone. In another embodiment, the control line contains antibody that is specific for, or otherwise provides for the immobilization of, the labeled reagent. In operation, a labeled reagent is restrained in each of the one or more control zones, even when any or all the analytes of interest are absent from the test sample. [0074] In a less occasional embodiment, a labeled control reagent is introduced into the fluid sample flow, upstream from the control zone. For example, the labeled control reagent may be added to the fluid sample before the sample is applied to the assay device. In frequent embodiments, the labeled control reagent may be diffusively bound in the sample receiving zone, but is preferably diffusively bound in the label zone. [0075] Exemplary functions of the labeled control reagents and zones include, for example, the confirmation that the liquid flow of the sample effectively solubilized and mobilized the labeled reagents deposited in the label zone, that a sufficient amount of liquid traveled correctly through the sample receiving zone, label zone, and the test and control zones, such that a sufficient amount of analyte could react with the corresponding specific label in the label zone, migrate onto the test region comprising the test and control zones, cross the test zone(s) in an amount such that the accumulation of the labeled analyte would produce a visible or otherwise readable signal in the case of a positive test result in the test zone(s). Moreover, an additional function of the control zones may be to act as reference zones which allow the user to identify the test results which are displayed as readable zones. [0076] Since the devices of the present invention may incorporate one or more control zones, the labeled control reagent and their corresponding control zones are preferably developed such that each control zone will become visible with a desired intensity for all control zones after fluid sample is contacted with the device, regardless of the presence or absence of one or more analytes of interest. [0077] In one embodiment, a single labeled control reagent will be captured by each of the control zones on the test strip. Frequently, such a labeled control reagent will be deposited onto or in the label zone in an amount exceeding the capacity of the total binding capacity of the combined control zones if multiple control zones are present. Accordingly, the amount of capture reagent specific for the control label can be deposited in an amount that allows for the generation of desired signal intensity in the one or more control zones, and allows each of the control zones to restrain a desired amount of labeled control reagent. At the completion of an assay, each of the control zones preferably provide a desired and/or pre-designed signal (in intensity and form). Examples of contemplated pre-designed signals include signals of equal intensities in each control zone, or following a desired pattern of increasing, decreasing or other signal intensity in the control zones. [0078] In another embodiment, each control zone will be specific for a unique control reagent. In this embodiment, the label zone may include multiple and different labeled control reagents, equaling the number of control zones in the assay, or a related variation. Wherein each of the labeled control reagents may become restrained in one or more pre-determined and specific control zone(s). These labeled control reagents can provide the same detectible signal (e.g., be of the same color) or provide distinguishable detectible signals (e.g., have different colored labels or other detection systems) upon accumulation in the control zone(s). [0079] In yet another embodiment, the control zones may include a combination of the two types of control zones described in the two previous embodiments, specifically, one or more control zones are able to restrain or bind a single type of labeled control reagent, and other control zones on the same test strip will be capable of binding one or several other specific labeled control reagents. [0080] In one embodiment, the labeled control reagent comprises a detectible moiety coupled to a member of a specific binding pair. Typically, a labeled control reagent is chosen to be different from the reagent that is recognized by the means which are capable of restraining an analyte of interest in the test zone. Further, the labeled control reagent is generally not specific for the analyte. In a frequent embodiment, the labeled control reagent is capable of binding the corresponding member of a specific binding pair or control capture partner that is immobilized on or in the control zone. Thus the labeled control reagent is directly restrained in the control zone. [0081] In another embodiment, the detectable moiety which forms the label component of the labeled control reagent is the same detectible moiety as that which is utilized as the label component of the analyte of interest labeled test reagent. In a frequent embodiment, the label component of the labeled control reagent is different from the label component of the labeled test reagent, so that results of the assay are easily determined. In another frequent embodiment, the control label and the test label include colored beads, e.g., colored latex. Also frequently, the control and test latex beads comprise different colors. [0082] In a further embodiment, the labeled control reagent includes streptavidin, avidin or biotin and the control capture partner includes the corresponding member of such specific binding pairs, which readily and specifically bind with one another. In one example, the labeled control reagent includes biotin, and the control capture partner includes streptavidin. The artisan will appreciate that other members of specific binding pairs can alternatively be used, including, for example, antigen/antibody reactions unrelated to analyte. [0083] The use of a control zone is helpful in that appearance of a signal in the control zone indicates the time at which the test result can be read, even for a negative result. Thus, when the expected signal appears in the control line, the presence or absence of a signal in a test zone can be noted. [0084] In still further embodiment, a control zone comprising a mark that becomes visible in the test region when the test regions is in a moist state is utilized. Control zones of this type are described in U.S. patent application Ser. No. 09/950,366, filed, Sep. 10, 2001, currently pending and published as U.S. Patent Application Publication No. 20030049167, and 10/241,822, filed Sep. 10, 2002, currently pending and published as U.S. Patent Application Publication No. 20030157699. [0085] In occasional embodiments, one or more control zones of this type are utilized. In another embodiment, a combination of control zones of the type utilizing labeled control reagents and control zone and of the type that display the control zone when in a moist state can be used. This allows a simple way to formulate control zones while allowing to use a reagent-based control zone to ascertain that the re-solubilization and mobilization of the reagents in the label pad process has been effective, and that the specific reactions took place as expected, all along the path defined by the sample pad, label pad, test strip and absorbent pad. The present embodiment includes the use of one or more control zones that become visible when the test region is in the moist state for each of the control zones of an assay, except the control zone on the distal or downstream end of the test strip. [0086] As indicated above, labeled test reagents are further provided which frequently comprise a test label coupled to a member of a specific binding pair that is capable of specifically binding an analyte of interest. Thus, in general, multiple labeled test reagents are positioned in the label zone, each of which is specific for a predetermined analyte of interest. [0087] Test zones of the present description include means that permit the restraint of an analyte of interest. Frequently, test zones of the present description include a ligand that is capable of specifically binding to an analyte of interest. Alternatively, test zones of the present description include a ligand that is capable of specifically binding the labeled reagent bound to an analyte of interest. In practice, a labeled test reagent binds an analyte of interest present in a fluid sample after contact of the sample with a representative device and flow of the fluid sample into and through the label zone. Thereafter, the fluid sample containing the labeled analyte progresses to a test zone and becomes restrained in the test zone. The accumulation of labeled analyte in the test zone produces a detectible signal. Frequently, devices of the present disclosure incorporate one or more test zones, each of which is capable of restraining different analytes, if present, in a fluid sample. Thus, in representative embodiments two, three, four, five or more (labeled) analytes of interest can be restrained in a single or different test zones, and thereby detected, in a single device. [0088] The present devices may optionally further comprise an absorbent zone that acts to absorb excess sample after the sample migrates through the test region. The absorbent zone, when present lies in fluid flow contact with the test region. This fluid flow contact can comprise an overlapping, abutting or interlaced type of contact. In an occasional embodiment, a control region (end of assay indicator) is provided in the absorbent zone to indicate when the assay is complete. In this embodiment, specialized reagents are utilized, such as pH sensitive reagents (such as bromocresol green), to indicate when the fluid sample has permeated past all of the test and control zones. Alternatively, the end of assay control region may be effected by applying a line of soluble ink on the test region after all of the test and control zones, and at the interface with the absorbent zone. In general, the liquid front moving through the capture zone will solubilize the ink and transfer it into the absorbent. The resulting color change will be seen in an observation window above the absorbent zone, signifying end of assay. Thus, these types of control regions are not specific for a particular analyte. Generally, the absorbent zone will consist of an absorbent material such as filter paper, a glass fiber filter, or the like. [0089] In an occasional embodiment, the fluid sample must be processed or treated prior to contact with the device to ensure accurate detection of at least one of the multiple analytes of interest. In this embodiment, a reagent, such as an extraction solution, may be used to prepare the sample. Alternatively, reagents can be added to the test device after initial contact with the fluid sample. For example, the sample is introduced to the device, and thereafter a reagent, such as a developer solution, is added to complete the assay. [0090] FIG. 1 provides various representative configurations of the presently contemplated devices. Although not specifically limited to dipstick type assays, these configurations may be incorporated in a dipstick-type assay among other types of immunoassay devices contemplated herein. The arrow in each Figure indicates the general direction of fluid sample flow after initial contact with the device. The boxes containing vertical lines and/or the diagonal lines depict control zones, and the boxes containing crosshatched lines depict test zones. The sample receiving zone [1], the label zone [2] and the test region [3] are also depicted. The present disclosure is not intended to be limited to the configurations depicted in FIG. 1(A-J) . These views are merely provided for illustrative purposes. For example, the test and control zones are not necessarily of the same shapes and sizes depicted in FIG. 1 . Further, the sample receiving zone, the label zone and test region are not necessarily presented to scale. FIG. 1A depicts a device having two test zones and a single control zone, wherein the control zone is situated between the test zones within the flow path. FIG. 1B depicts a device having three test zones and two control zones, wherein the control zones are situated between the test zones within the flow path. Further, in FIG. 1B , the second test zone is situated between the two control zones within the flow path. FIG. 1C depicts a device having four test zones and two control zones, wherein the control zones are situated between the test zones within the flow path. Further, in FIG. 1C , the second and third test zones are adjacent without a control zones between these zones. FIG. 1D depicts a device having two test zones and a single control zone, wherein the control zone is situated downstream of the test zones within the flow path. FIG. 1E depicts a device having two test zones and a single control zone, wherein the control zone is situated upstream of the test zones within the flow path. FIG. 1F depicts a device having four test zones and three control zones, wherein the control zones are situated between the test zones within the flow path in a alternating fashion. FIG. 1G depicts a device having five test zones and one control zone, wherein the control zone is situated between the second to last and last test zones within the flow path. Further, in FIG. 1G , the first through fourth test zones are adjacent to one another without having control zones between each test zone. FIG. 1H depicts a device having three test zones and one control zone, wherein the control zone is situated between the second and third test zones within the flow path. FIG. 1I depicts a device having four test zones and three control zones (wherein two control zones are comprised of the same labeled-control reagent and binding reagent specific pair (or alternatively, are comprised of motifs that become visible when the test zone is moist), but one control zone (as indicated by the diagonal lines) is comprised of one distinct pair of labeled control reagent and control zone binding reagent). FIG. 1J depicts a device having four test zones and three control zones (wherein one control zone is comprised of the same labeled-control reagent and binding reagent specific pair (or alternatively, are comprised of motifs that become visible when the test zone is moist), but two control zones (as indicated by the diagonal lines) are comprised of one distinct pair of labeled control reagent and control zone binding reagent). Frequently, when two types of control zones or pairs of control zones reagents are used, each control zone may be colored differently. Other device configurations within the scope of the present disclosure are contemplated. For example, although not depicted, the present disclosure contemplates a device having one test zone and one control zone, wherein multiple analytes can be detected within the test zone. [0091] Those of skill in the art will recognize that a variety of direct and indirect assay formats may be employed in the present devices. In a frequent embodiment, a direct assay format is utilized. Direct assays are exemplified by those that detect the presence of an antigen in a sample, as well as those that detect the presence of an antibody in a sample. [0092] As provided above, particular devices of the present invention include a support. The support in these devices provides a convenient platform for performance of the assay. However, the composition and shape of the support are not critical and may vary. Occasionally, the support may be comprised of a plastic or nylon material. [0093] In frequent embodiment, the present devices are in the form of a dipstick. Generally, dipsticks of the present invention are functionally analogous to the lateral assays described herein excepting the method of contacting a fluid sample. In embodiments configured as a dipstick, the matrix and support will generally be located on one end of the dipstick. The configuration of such devices will allow the device to be dipped or contacted with a fluid sample with one end of a matrix i.e., the sample receiving zone. After contacting the fluid sample, the sample preferably migrates in an axial flow path through the matrix from the sample receiving zone to the label zones and test region. Alternatively, the devices of the present invention may be shaped so that samples may be applied to the device by means other than dipping, e.g., application of controlled amounts of sample by pipettes or the like. [0094] The present invention is further described by the following examples. The examples are provided solely to illustrate the invention by reference to specific embodiments. These exemplifications, while illustrating certain specific aspects of the invention, do not portray the limitations or circumscribe the scope of the disclosed invention. EXAMPLES Exemplary Test Device for Distinguishing Influenza A from Influenza B [0095] An immunoassay device for use in determining the presence of and distinguishing between multiple analytes was constructed in accordance with the present invention. In particular, an immunoassay dipstick capable of diagnosing influenza and distinguishing between influenza A and influenza B infection was prepared. Those of skill in the art are familiar with the general methods for preparation of immunoassay dipstick devices (see, e.g., U.S. Pat. No. 5,712,172) as well as other lateral flow immunoassays. The exemplary device described herein may likewise be so constructed. [0096] The exemplary test device comprised a sample pad containing sample conditioning reagents, a label pad containing monoclonal antibody against Influenza A nucleoprotein covalently bound to red colored latex microparticles (Duke Scientific), a monoclonal antibody against Influenza B nucleoprotein covalently bound onto red colored latex microparticles, and an unrelated protein (in this example, biotinylated BSA) bound to blue latex microparticles (Duke Scientific). The device was assembled, in order, as a sample pad in fluid communication with a label pad in fluid communication with a test pad (observation zone) in fluid communication with an absorbent pad at the device end. The pads were laminated, using 3M adhesive, onto a Mylar backing, in sequence and in fluid communication to allow lateral flow from one pad to the next. A strip of plastic material, comprising a cutout (“window”) over the observation zone, was then laminated on top of the device leaving a portion of the sample pad exposed for sample application. This plastic cover served the purpose of securing the pads in place and in overlapping contact with one another, so that fluid communication was maintained there between. Additionally, the plastic material was selected to provide sufficient rigidity to the final device to allow convenient handling by the user and to isolate the areas of the dipstick that are moistened during the testing process. [0097] The observation zone was made of a Highflow Plus nitrocellulose membrane from Millipore laminated onto a white Mylar backing. Test and control reagents were deposited, using standard techniques, onto the observation zone membrane in the form of 3 lines, each perpendicular to the flow of sample and in order upstream to downstream as follows: anti-Flu B monoclonal antibodies against a second epitope of the Influenza B nucleoprotein at a concentration of about 3 mg/ml in phosphate buffer was deposited as the a first test zone; at about 3 mm downstream of the first test zone, a control zone was formed by depositing streptavidin labeled BSA; and at about 3 mm downstream of the first control zone a second test zone was formed by depositing an antibody against a second epitope of the Influenza A nucleoprotein (again, at a concentration of about 3 mg/ml in phosphate buffer). Thus, the two test zones and one control zone were configured as illustrated in FIG. 1A . [0098] Once the test and control reagents were deposited and dried onto the nitrocellulose membrane, the membrane was rendered non-bibulous by treatment with a blocking solution. As discussed above, non-bibulous flow allows the components of interest in the assay to move at substantially the same rate along the test strip without preferential retention of such components. This facilitates flow of a sufficient quantity of labeled material across the test and control zones, such that positioning of the control line upstream of the second test line does not interfere with the effectiveness or reliability of the control zone. [0099] At the end of the test device, the observation zone is in fluid contact with a pad of absorbent material, in this example, made of absorbent cellulosic paper (Whatman). [0100] As is common in the industry, the concentration of each component was optimized during development of the test to allow the assay to reach the required sensitivity while avoiding non-specific binding. For instance, the colored latex/anti-Influenza A antibody conjugate was diluted serially and deposited onto label pads that were dried, assembled into functional strips, and tested with liquid samples of the viral nucleoprotein at concentrations ranging from 7.5 ng/ml to 100 ng/ml. The lowest concentration of conjugate allowing detection of the 7.5 ng/ml solution of the nucleoprotein was selected as optimal. The optimal concentration of anti-Influenza B antibody/colored latex conjugate was similarly optimized. The optimum concentration of the control protein/colored latex conjugate was selected to provide a line clearly visible to the eye after normal incubation of the assay. To construct the final product, the optimized label (conjugate) solutions were mixed together then applied to and dried on the label pad using standard techniques. [0101] The size/capacity of the absorbent pad was optimized to ensure that a sufficient amount of sample liquid would move through the test strip and across the two test and one control zones to product a visible, accurate signal when as little as 7.5 ng/ml of Influenza A and 7.5 ng/ml of Influenza B nucleoproteins were present in the sample. Test of Exemplary Device [0102] To confirm that positioning of a control zone upstream of a test zone would not compromise the accuracy of a device according to the present invention, two devices were created and compared to one another. Both devices were constructed as described above, except that each was constructed with only an Influenza A test zone (single analyte). In one device, the control zone was located upstream of the test zone and in the second device the control zone was located downstream of the test zone. A sample of Influenza A nucleoprotein at a relatively low concentration (sufficient to generate a visible signal of about 0.030 O.D. measured on an optical density scanner after a 10 minute incubation) was prepared and applied to each device. FIG. 2 shows the ratios between the O.D. values of the test zone and the control zone for different volumes of sample for each of the two devices. Increasing sample volumes were used, ranging from 25 uL up to 300 uL, facilitating identification of the minimum sample volume required to generate sufficient signal for the assay to meet design specifications. The graph in FIG. 2 clearly shows that the ratios of the signals generated by the test zone and control zone in the two devices are virtually identical regardless of the position of the test zone relative to the control zone. [0103] The above examples are included for illustrative purposes only and are not intended to limit the scope of the invention. Many variations to those described above are possible. Since modifications and variations to the examples described above will be apparent to those of skill in this art, it is intended that this invention be limited only by the scope of the appended claims. Citation herein of publications or documents is not intended as an admission that any of the foregoing is pertinent prior art.

The present invention relates generally to an assay for detecting and differentiating multiple analytes, if present, in a single fluid sample, including devices and methods therefore.

CROSS REFERENCES TO RELATED APPLICATIONS The present application claims priority from Japanese Patent Application No. JP 2007-294313, filed in the Japanese Patent Office on Nov. 13, 2007, the entire content of which is incorporated herein by reference. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information processing apparatus, an information processing method, an a program and, more particularly, to an information processing apparatus, an information processing method, and a program that are suitably for use in the identification of video contents of video data represented by television programs, for example. 2. Description of the Related Art For example, methods are proposed for identifying the video contents in order to automatically generate digests of television programs and automatically extract highlight scenes. The video contents of time-series video data of television programs for example are identified by a method that uses one of probabilistic models, or HMM (Hidden Markov Model) that is able to use time-series data as a target of processing (refer to “Automatic Indexing for Baseball Broadcast based on Hidden Markov Model,” Image Recognition and Understanding Symposium (MIRU2005), July 2005 by Nguyen Huu Back, Koichi Shinoda, Sada Furui, hereinafter referred to as Non-Patent Document 1 for example) Non-Patent Document 1 describes a method of identifying the video contents of baseball live coverage by use of HMM. To be specific, the HMMs corresponding to the video contents (for example, pitching scene, homerun scene, infield grounder scene, walking scene, strikeout scene, and so on) of a baseball live coverage are generated by learning in advance and the video data of a baseball live coverage is supplied to each learned HMM, thereby recognizing a scene corresponding to the HMM having a largest output likelihood value, as the video contents of the baseball live coverage. Each HMM outputs a likelihood value that the video data to be entered is indicative of a corresponding scene. For example, the HMM corresponding to a homerun scene outputs a likelihood value that the video data to be entered is indicative of a homerun scene. SUMMARY OF THE INVENTION Related-art video identification techniques based on the above-mentioned HMM can recognize video contents. However, these related-art techniques sometimes involve the erroneous recognition of video contents, thereby requiring a novel technique that is capable of identifying video contents with higher accuracy than before. Therefore, the present invention addresses the above-identified and other problems associated with related-art methods and apparatuses and solves the addressed problems by providing an information processing apparatus, an information processing method, and a computer program that are capable of identifying video contents with higher accuracy. According to an embodiment of the present invention there is provided an information processing apparatus configured to classify time-series input data into N classes. This above-mentioned information processing apparatus has time-series feature quantity extracting means for extracting a time-series feature quantity of the time-series input data; N calculating means for calculating, by applying the extracted time-series feature quantity to a probabilistic model learned in advance, likelihood values that the time-series input data belongs to any one of the N classes; and determination means for determining, by applying one of patterns of N dimension and dimensions higher than N that includes the calculated N likelihood values to pattern identification sections learned in advance, whether the time-series input data belongs to which of the N classes. In the above-mentioned information processing apparatus, the time-series input data is video data and the N classes are scenes of N different types that are video contents of the video data. The information processing apparatus further has non-time-series feature quantity extracting means for extracting a non-time-series feature quantity of the time-times input data. In this information processing apparatus, the determination means, by applying (N+M)-dimension patterns including the N calculated likelihood values and M extracted non-time-series feature quantities to a pattern identification section learned in advance, determines whether the time-series input data belongs to which of the N classes. In the above-mentioned processing apparatus, the probabilistic model is a Hidden Markov Model and the pattern identification section is a neural network. According to another embodiment of the present invention there is provided an information processing method for an information processing apparatus configured to classify time-series input data into N classes. The above-mentioned information processing method has the steps of: extracting a time-series feature quantity of the time-series input data; calculating, by applying the extracted time-series feature quantity to a probabilistic model learned in advance, likelihood values that the time-series input data belongs to any one of the N classes; and determining, by applying one of patterns of N dimension and dimensions higher than N that includes the calculated N likelihood values to pattern identification sections learned in advance, whether the time-series input data belongs to which of the N classes. According to still another embodiment of the present invention, there is provided a program for controlling an information processing apparatus configured to classify time-series input data into N classes. The above-mentioned program has the steps of: extracting a time-series feature quantity of the time-series input data; calculating, by applying the extracted time-series feature quantity to a probabilistic model learned in advance, likelihood values that the time-series input data belongs to any one of the N classes; and determining, by applying one of patterns of N dimension and dimensions higher than N that includes the calculated N likelihood values to pattern identification sections learned in advance, whether the time-series input data belongs to which of the N classes. According to an embodiment of the present invention, a time-series feature quantity of time-series input data is extracted. The extracted time-series feature quantity is applied to a probabilistic model that has been learned in advance to calculate a likelihood value that the time-series input data belongs to any one of N classes. In addition, patterns of N or higher dimensions including the calculated N classes are applied to pattern identification sections that have been learned in advance to determine whether the time-series input data belong to which of the N classes. Embodiments of the present invention allow the classification of time-series input data with significantly high accuracy. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram illustrating a first exemplary configuration of a video data identification apparatus practiced as one embodiment of the invention; FIG. 2 is a block diagram illustrating an exemplary configuration of a time-series learning apparatus configured to make a by-scene HMM identification block shown in FIG. 1 learn; FIG. 3 is a flowchart indicative of learning processing corresponding to the video data identification apparatus shown in FIG. 1 ; FIG. 4 is a flowchart indicative of scene identification processing to be executed by the video data identification apparatus shown in FIG. 1 ; FIG. 5 is a block diagram illustrating a second exemplary configuration of a video data identification apparatus practiced as one embodiment of the invention; FIG. 6 is a flowchart indicative of learning processing of the video data identification apparatus shown in FIG. 5 ; FIG. 7 is a flowchart indicative of scene identification processing to be executed by the video data identification apparatus shown in FIG. 5 ; and FIG. 8 is a block diagram illustrating an exemplary configuration of a general-purpose computer. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS This invention will be described in further detail by way of embodiments thereof with reference to the accompanying drawings. Now referring to FIG. 1 , there is shown an exemplary configuration of a video data identification apparatus practiced as a first embodiment of the invention. This video data identification apparatus 10 processes video data, such as television programs that are entered in a time-series manner, identifying the time-series data of video contents of entered video data. The video data identification apparatus 10 is made up of a time-series identification section 11 and a pattern identification section 12 . The following describes the identification of video contents (a pitching scene, a homerun scene, an infield grounder scene, a walking scene, a strikeout scene, and so on) of the video data of a baseball live coverage program, for example. The time-series identification section 11 is configured to identify video data by use of HMM for example and is made up of a time-series feature quantity extraction block 21 and a plurality of by-scene HIM identification blocks 22 - 1 through 22 -N. The time-series feature quantity extraction block 21 divides video data into predetermined intervals (for example, several seconds or several frames) and extracts feature quantities based on move quantity, image histogram and main component analysis, a fractal feature quantity, and an inter-frame luminance difference feature quantity, for example. The extracted time-series feature quantities are supplied to the by-scene HMM identification blocks 22 - 1 through 22 -N. The by-scene HMM identification block 22 - 1 computes a likelihood value that a time series feature quantity (to be described later) was learned in advance in correspondence with one scene (a pitching scene for example) supposed as the video contents of video data and a time-series feature quantity entered from the time-series feature quantity extraction block 21 is that of a corresponding scene (a pitching scene in this case). The by-scene HMM identification block 22 - 2 computes a likelihood value that a time series feature quantity (to be described later) was learned in advance in correspondence with one scene (a homerun scene for example) supposed as the video contents of video data and a time-series feature quantity entered from the time-series feature quantity extraction block 21 is that of a corresponding scene (a homerun scene in this case). Likewise, the by-scene HMM identification blocks 22 - 3 through 22 -N compute a likelihood value that a time series feature quantity (to be described later) was learned in advance in correspondence with different scenes supposed as the video contents of video data and time-series feature quantities entered from the time-series feature quantity extraction block 21 is those of corresponding scenes. Therefore, the time-series identification section 11 outputs N-types of likelihood values as information indicative whether the video contents of entered video data are supposed N-types of scenes or not. The pattern identification section 12 executes pattern recognition by use of a neural network (hereafter also referred to as NN) and is made up of an input pattern generating block 31 and a scene decision block 32 . The input pattern generating block 31 generates an N-dimension input patterns on the basis of N likelihood values entered from the by-scene HMM identification blocks 22 - 1 through 22 -N of the time-series identification section 11 and outputs the generated input patterns to the scene decision block 32 . The previously learned scene decision block 32 computes the likelihood values of the N-types of scenes of the N-dimension input patterns supplied from the input pattern generating block 31 and outputs a scene corresponding to the greatest of the obtained values as a video content recognition result. It should be noted that the learning of the scene decision block 32 can be made by a back propagation algorithm for example by use of learning video data (with time-series scenes identified by man). Referring to FIG. 2 , there is shown an exemplary configuration of a time-series learning apparatus 40 for learning the by-scene HMM identification blocks 22 - 1 through 22 -N shown in FIG. 1 by use of learning video data. The time-series learning apparatus 40 is made up of a time-series feature quantity extraction block 41 , an operator block 42 , a selector 43 , and by-scene HMM learning blocks 44 - 1 through 44 -N. The time-series feature quantity extraction block 41 , like the time-series feature quantity extraction block 21 shown in FIG. 1 , divides video data into predetermined intervals (for example, several seconds or several frames) and extracts feature quantities based on move quantity, image histogram and main component analysis, a fractal feature quantity, and an inter-frame luminance difference feature quantity, for example, and outputs the extracted feature quantities to the selector 43 . The operator block 42 is operated by an operator (or a user) who identify learning video data scenes for example. A scene identification result is supplied to the selector 43 through the operator block 42 . In response to the scene identification result supplied from the operator through the operator block 42 , the selector 43 supplies a time-series feature quantity supplied from the time-series feature quantity extraction block 41 to one of the by-scene HMM learning blocks 44 - 1 through 44 -N. It should be noted that the by-scene HMM learning blocks 44 - 1 through 44 -N are respectively related to different video contents (a pitching scene, a homerun scene, an infield grounder scene, a walking scene, a strikeout scene, and so on). For example, assume that the by-scene HMM learning block 44 - 1 is related to a pitching scene, the by-scene HMM learning block 44 - 2 is related to a homerun scene, and the by-scene HMM learning block 44 - 3 is related to an infield grounder scene. Then, if the video contents of learning video data is identified by the operator to be a homerun scene and the operator block 42 is operated accordingly, the selector 43 supplies the time-series feature quantity of that scene to the by-scene HMM learning block 44 - 2 . If the video contents of learning video data is identified by the operator to be an infield grounder scene and the operator block 42 is operated accordingly, the selector 43 supplies the time-series feature quantity of that scene to the by-scene HMM learning block 44 - 3 . The by-scene HMM learning block 44 - 1 through 44 -N learn HMM on the basis of the time-series feature quantity supplied via the selector 43 . For this learning, the Baum-Welch algorithm can be used. Then, the learning is repeatedly executed by use of two or more different learning video data until the identification by the by-scene HMM learning blocks 44 - 1 through 44 -N has reached a desired accuracy. When the identification is found reaching a desired accuracy, the final HMM of the by-scene HMM learning blocks 44 - 1 through 44 -N is applied to the by-scene HMM identification blocks 22 - 1 through 22 -N of the time-series identification section 11 shown in FIG. 1 . The following describes the previous learning processing for the video data identification apparatus 10 to be able to identify video data scenes more accurately, with reference to a flowchart shown in FIG. 3 . First, in steps S 1 through S 3 , the by-scene HMM identification blocks 22 - 1 through 22 -N of the time-series identification section 11 are learned. To be more specific, in step S 1 , the time-series feature quantity extraction block 41 of the time-series learning apparatus 40 divides the learning video data into predetermined intervals to extract a time-series feature quantity of each interval and outputs the extracted time-series feature quantities to the selector 43 . In step S 2 , in response to a result of scene identification made by the user through the operator block 42 , the selector 43 supplies the time-series feature quantity supplied from the time-series feature quantity extraction block 41 to one of the by-scene HMM learning blocks 44 - 1 through 44 -N. On the basis of the time-series feature quantity supplied from the selector 43 , the by-scene HMM learning blocks 44 - 1 through 44 -N learn HMM. In step S 3 , it is determined whether the identification by the by-scene HMM learning blocks 44 - 1 through 44 -N has reached a desired accuracy. Until a desired accuracy is reached, the processes of steps S 1 through S 3 are repeatedly executed. If the identification by the by-scene HMM learning blocks 44 - 1 through 44 -N is found reaching a desired accuracy in step S 3 , the final HMM of the by-scene HMM learning blocks 44 - 1 through 44 -N is applied to the by-scene HMM identification blocks 22 - 1 through 22 -N of the time-series identification section 11 shown in FIG. 1 . Then, the procedure goes to step S 4 . In steps S 4 through S 8 , the scene decision block 32 of the pattern identification section 12 is learned. To be more specific, in step S 4 , a time-series feature quantity is extracted from the learning video data and the extracted time-series feature quantity is supplied to the by-scene HMM identification blocks 22 - 1 through 22 -N learned in the above-mentioned steps S 1 through S 3 . In step S 5 , the by-scene HMM identification blocks 22 - 1 through 22 -N compute likelihood values that the supplied time-series feature quantities corresponds to supposed scenes and output the obtained likelihood values to the input pattern generating block 31 . In step S 6 , the input pattern generating block 31 generates an N-dimension input patterns on the basis of N likelihood values entered from the by-scene HMM identification blocks 22 - 1 through 22 -N and outputs the generated N-dimension input patterns to the scene decision block 32 . In step S 7 , the scene decision block 32 learns NN on the basis of the N-dimension input patterns supplied from the input pattern generating block 31 and the result of the scene identification by the operator who viewed the learning video data. In step S 8 , it is determined whether the identification by the scene decision block 32 has reached a desired accuracy or not. The processes of steps S 4 through 8 are repeatedly executed until a desired accuracy is reached. If the identification by the scene decision block 32 is found reaching a desired accuracy in step S 8 , then the learning processing comes to an end. The following describes video data scene identification processing by the video data identification apparatus 10 including the by-scene HMM identification blocks 22 - 1 through 22 -N and the scene decision block 32 that have been learned by the above-mentioned learning processing, with reference to a flowchart shown in FIG. 4 . In step S 11 , the time-series feature quantity extraction block 21 of the time-series identification section 11 divides the video data subject to processing into predetermined intervals to extract time-series feature quantities thereof. In step S 12 , the time-series feature quantity extraction block 21 supplies the extracted time-series feature quantities to the by-scene HMM identification blocks 22 - 1 through 22 -N. The by-scene HMM identification blocks 22 - 1 through 22 -N compute the likelihood value that the supplied time-series feature quantities are of the corresponding scenes (pitching scene, homerun scene, infield grounder scene, walking scene, strikeout scene, and so on). The obtained likelihood values are supplied to the input pattern generating block 31 of the pattern identification section 12 . In step S 13 , the input patterns generating block 31 generates an N-dimension input patterns on the basis of the N likelihood values entered from the by-scene HMM identification blocks 22 - 1 and 22 -N of the time-series identification section 11 and outputs the generated N-dimension input patterns. In step S 14 , the scene decision block 32 computes a likelihood value of each of the N-types of scenes of the N-dimension input patterns entered from the input patterns generating block 31 and outputs a scene corresponding to the greatest value of the obtained likelihood values as a video content identification result. Thus, the scene identification processing by the video data identification apparatus 10 has been described. As described, the video data identification apparatus 10 identifies video data scenes not by use of HMM, but by the pattern decision based N likelihood value patterns outputted from two or more HMMs, so that chances of error decision can be reduced, thereby enhancing the accuracy of identification. The following describes an exemplary configuration of the video data identification apparatus practiced as a second embodiment of the invention. This video identification apparatus 70 is made up of substantially the same time-series identification section 11 of the video data identification apparatus 10 shown in FIG. 1 , non-time-series feature extraction blocks 71 - 1 through 71 -N configured to extract non-time-series feature quantities from video data subject to processing, and a pattern identification section 72 . The non-time-series feature quantity extraction blocks 71 - 1 through 71 -N divides the video data subject to processing into predetermined intervals (for example, several seconds or several frames), extracts a representative image pattern, a representative color, a representative object on the screen, and so on, as non-time-series feature quantities, and outputs the extracted information to the pattern identification section 72 . The pattern identification section 72 executes pattern identification by use of NN, for example, and is made up of an input pattern generating block 81 and a scene decision block 82 . The input pattern generating block 81 generates (N+M)-dimension input patterns on the basis of N likelihood values entered from the by-scene HMM identification blocks 22 - 1 through 22 -N of the time-series identification section 11 and M non-time-series feature quantities entered from the non-time-series feature quantity extraction blocks 71 - 1 through 71 -M and outputs the generated input patterns to the scene decision block 82 . The scene decision block 82 learned in advance computes the likelihood values of N-types of scenes of the (N+M) input patterns entered from the input pattern generating block 81 and outputs the scene corresponding to the greatest value of the obtained likelihood values as a video contents identification result. It should be noted that the learning of scene decision block 82 can be executed by a back propagation algorithm, for example, by use of learning video data (with time-series scenes identified by man). The following describes the learning processing to be executed in advance so as for the video identification apparatus 70 to identify video data scenes more accurately, with reference to a flowchart shown in FIG. 6 . First, like the processes of step S 1 through S 3 shown in FIG. 6 above, the by-scene HMM identification blocks 22 - 1 through 22 -N of the time-series identification section 11 are learned by the processes of steps S 31 through S 33 . Next, in steps S 34 through 39 , the scene decision block 82 of the pattern identification section 72 is learned. To be more specific, in step S 34 , a time-series feature quantity is extracted from the learning video data and the extracted time-series feature quantity is supplied to the by-scene HMM identification blocks 22 - 1 through 22 -N learned in steps S 31 through S 33 . In step S 35 , the by-scene HMM identification blocks 22 - 1 through 22 -N compute a likelihood value that the supplied time-series feature quantities correspond to supposed scenes and outputs the obtained likelihood value to the input pattern generating block 81 of the pattern identification section 72 . In step S 36 , the non-time-series feature quantity extraction blocks 71 - 1 through 71 -M divide the learning video data into predetermined intervals to extract non-time-series feature quantities thereof and outputs the extracted non-time-series feature quantities to the input pattern generating block 81 of the pattern identification section 72 . In step S 37 , the input pattern generating block 81 generates (N+M)-dimension input patterns on the basis of the N likelihood values entered from the by-scene HMM identification blocks 22 - 1 through 22 -N and the non-time-series feature quantity extraction blocks 71 - 1 through 71 -M and outputs the generated input patterns to the scene decision block 82 . In step S 38 the scene decision block 82 learns NN on the basis of the (N+M)-dimension input patterns entered from the input pattern generating block 81 and the result of the scene identification by the operator who viewed the learning video data. In step S 39 , it is determined whether the identification by the scene decision block 82 has reached a desired accuracy or not. The processes of steps S 34 through S 39 are repeatedly executed until a desired accuracy is reached. If the identification by the scene decision block 82 is found reaching a desired accuracy in step S 39 , then this learning processing comes to an end. The following describes video data scene identification processing to be executed by the video data identification apparatus 70 including the by-scene HMM identification block 22 - 1 through 22 -N and the scene decision block 82 that have been learned by the above-mentioned learning processing, with reference to a flowchart shown in FIG. 7 . In step S 51 , the time-series feature quantity extraction block 21 of the time-series identification section 11 divides the video data subject to processing into predetermined intervals to extract time-series feature quantities thereof. In step S 52 , the time-series feature quantity extraction block 21 supplies the extracted time-series feature quantities to the by-scene HMM identification blocks 22 - 1 through 22 -N. The by-scene HMM identification block 22 - 1 through 22 -N compute the likelihood value that the supplied time-series feature quantities are those of corresponding scenes (a pitching scene, a homerun scene, an infield grounder scene, a walking scene, a strikeout scene, and so on). The obtained likelihood value is supplied to the input pattern generating block 81 of the pattern identification section 72 . In step 53 , the non-time-series feature quantity extraction blocks 71 - 1 through 7 -M divide the video data subject to processing into predetermined intervals to extract non-time-series feature quantities hereof and outputs the extracted non-time-series feature quantities to the input pattern generating block 81 . In step S 54 , the input pattern generating block 81 generates (N+M)-dimension patterns on the basis of N likelihood values entered from the by-scene HMM identification blocks 22 - 1 through 22 -N and M non-time-series feature quantities entered from the non-time-series feature quantity extraction blocks 71 - 1 through 71 M and outputs the generated patterns to the scene decision block 82 . In step S 55 , the scene decision block 82 computes the likelihood values of the N-types of scenes of the (N+M)-dimension input patterns entered from the input pattern generating block 81 and outputs the scene corresponding to the greatest value of the obtained likelihood values as a video contents identification result. Thus, the scene identification processing executed by the video data identification apparatus 70 has been described. As described, the video data identification apparatus 10 identifies video data scenes not by use of HMM, but by the pattern decision based on the patterns of N likelihood values and M non-time-series feature quantities outputted from the HMMs, so that the chances of erroneous identification can be reduced as compared with the identification based on only HMM, thereby enhancing the accuracy of identification. The above-mentioned novel configuration also allows the scene identification by use of non-time-series feature quantities. As described above, HMM is used for the time-series identification section 11 in the above-mentioned embodiments of the invention; however, it is also practicable to use other probabilistic models other than HMM. As described above, NN is used for the pattern identification section 12 and the pattern identification section 72 ; however it is also practicable to use other pattern recognition algorithm than NN. It should be noted that the embodiments of the present invention is applicable to not only the scene identification of video data, but also the classification of time-series data of given types. The above-mentioned sequence of processing operations may be executed by software as well as hardware. When the above-mentioned sequence of processing operations is executed by software, the programs constituting the software are installed in a computer which is built in dedicated hardware equipment or installed, from a network or recording media, into a general-purpose personal computer for example in which various programs may be installed for the execution of various functions. Referring to FIG. 8 , there is shown a block diagram illustrating an exemplary hardware configuration of a computer configured to execute the above-mentioned sequence of processing operations by software programs. In this computer 100 , a CPU (Central Processing Unit) 101 , a ROM (Read Only Memory) 102 , a RAM (Random Access Memory) 103 are interconnected by a bus 104 . The bus 104 is further connected to an input/output interface 105 . The input/output interface 105 is connected to an input block 106 having a keyboard, a mouse, a microphone, and so on, an output block 107 having a display monitor, a loudspeaker, and so on, a storage block 108 based on hard disk or a nonvolatile memory, a communication block 109 based on a network interface, and a drive 110 for driving a removable media 111 , such as a magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory, for example. In the computer 100 thus configured, the CPU 101 loads programs stored in the storage 108 into the RAM 103 via the input/output interface 105 and the bus 104 so as to execute the above-mentioned sequence of processing operations, for example. It should be noted herein that the steps for describing each program recorded in recording media include not only the processing operations which are sequentially executed in a time-dependent manner but also the processing operations which are executed concurrently or discretely. It should also be noted that programs may be executed by a single unit of computer or two or more units of computer in a distributed manner or transferred to a remote computer for execution. While preferred embodiments of the present invention have been described using specific terms, such description is for illustrative purpose only, and it is to be understood that changes and variations may be made without departing from the spirit or scope of the following claims.

Disclosed herein is an information processing apparatus configured to classify time-series input data into N classes, including, a time-series feature quantity extracting section, N calculating sections, and a determination section.

RELATED APPLICATIONS Not Applicable FEDERALLY SPONSORED RESEARCH Not Applicable SEQUENCE LISTING Not Applicable BACKGROUND OF THE INVENTION The invention generally relates to oxygen concentrators, and more particularly relates to portable medical oxygen concentrators used by patients as a 24 hour a day source of supplemental oxygen. Portable oxygen concentrators are becoming an increasingly desirable mode of supplying portable oxygen needs to patients requiring Long Term Oxygen Therapy (LTOT). These portable oxygen concentrators are replacing compressed gas cylinders and liquid oxygen systems, which have been the standard of care for many years. Replacing cylinders and liquid oxygen with a portable oxygen concentrator gives a patient the ability to travel onboard aircraft and avoid the requirement to return home to refill a liquid system or exchange empty cylinders. A particularly useful class of portable oxygen concentrators is designed to be used 24 hours a day, allowing users to move about and to travel for extended periods of time without the inconvenience of managing separate oxygen sources for home and portable use. These portable oxygen concentrators are typically in the range of 2 to 20 lbs and produce from 0.3 to 5.0 LPM of oxygen. Most of these portable concentrators are based on Pressure Swing Adsorption (PSA) or Vacuum Pressure Swing Adsorption (VPSA) designs which feed compressed air to selective-adsorption beds. In a typical oxygen concentrator, the beds utilize a zeolite adsorbent to selectively adsorb nitrogen, resulting in pressurized, oxygen-rich product gas. The main elements in a typical portable therapeutic oxygen concentrator are shown in FIG. 1 . Air is draw in, and typically filtered, at air inlet 1 before being pressurized by compressor 2 to a pressure of 1.2 to 2.5 atmospheres. The pressurized air is directed by a valve arrangement through adsorbent beds 3 . An exemplary adsorbent bed implementation, used in a concentrator design developed by the inventors, is two columns filled with a lithium exchanged zeolite adsorbent in the ratio of about 1 gram of adsorbent per 1-5 ml of oxygen produced. The pressurized air is directed through these adsorber vessels or columns in a series of steps which constitute a gas separation cycle, often a PSA cycle or some variation including vacuum instead of, or in conjunction with, compression yielding overall compression ratios of about 1.5:1 to 4.0:1. Although many different arrangements of adsorber vessels and gas separation cycles are possible, the result is that nitrogen is removed by the adsorbent material, and the resulting oxygen rich gas is routed to a product gas storage device at 4 . Some of the oxygen product gas can be routed back through the bed to flush out (purge) the adsorbed nitrogen to an exhaust 6 . Generally multiple adsorbent beds, or columns in the exemplary device, are used so at least one bed may be used to make product while at least one other bed is being purged, ensuring a continuous flow of product gas. The purged gas is exhausted from the concentrator at the exhaust 6 . Such gas separation systems are known in the art, and it is appreciated that the gas flow control through the compressor and the adsorbent beds is complex and requires precise timing and control of parameters such as pressure, flow rate, and temperature to attain the desired oxygen concentration of 80% to 95% purity in the product gas stream. Accordingly, most modern concentrators also have a programmable controller 5 , typically a microprocessor, to monitor and control the various operating parameters of the gas separation cycle. In particular, the controller controls the timing and operation of the various valves used to cycle the beds through feed and purge and pressure equalization steps which make up the gas separation cycle. Also present in most portable concentrators is a conserver 7 which acts to ensure that oxygen rich gas is only delivered to a patient during inhalation. Thus, less product gas is delivered than by means of a continuous flow arrangement, thereby allowing for smaller, lighter concentrator designs. A pulse of oxygen rich air, called a bolus, is delivered in response to a detected breath via the conserver. Using a conserver in conjunction with a gas concentrator may reduce the amount of oxygen required to maintain patient oxygen saturation by a factor of about 2:1 to 9:1 A typical concentrator will also contain a user/data interface 8 including elements such as an LCD display, alarm LEDs, audible buzzers, and control buttons. In addition to the above subsystems, most portable oxygen concentrators contain a rechargeable battery and charging system to power the concentrator while away from an AC or DC power source. These battery systems are typically composed of lithium ion cells and can power the concentrator from 2-12 hours depending on the amount of oxygen required by the patient and the capacity of the battery pack. To be practical and usable by a individual needing therapeutic oxygen, portable oxygen concentrators should be less than about 2100 cubic inches and preferably less than 600 cubic inches in total volume, less than about 20 pounds and preferably less than 8 pounds in weight, and produce less than about 45 decibels of audible noise, while retaining the capacity to produce a flow of product gas adequate to provide for a patient's oxygen needs, usually a flow rate prescribed by a medical practitioner in about the range of 1 LPM to 6 LPM. Further, a portable medical oxygen concentrator must work under varied environmental and physical conditions without costly or frequent service or maintenance requirements and should be able to run for upwards of 20,000 hours before major maintenance is required, such as a compressor rebuild. Although fixed site PSA based concentrators have been available for many years, such fixed site units may weigh 30-50 pounds or more, be several cubic feet in size, and produce sound levels greater than 45 dBA. Thus portable concentrators involve a significant amount of miniaturization, leading to smaller, more complex designs compared to stationary units, yet they must remain relatively low cost to be available to a wide range of users. System size, weight, and complexity may lead to a necessarily higher degree of integration and design optimization. Moreover, the cost constraints of portable concentrators preclude the use of multiple pressure, temperature, and concentration sensors used by large scale industrial concentrators to help optimize efficiency. Significant teachings in concentrator art exist on just the subject of monitoring and control of various parts of the PSA process. Yet ultra-small portable concentrators have as much or greater need to accomplish such process control. A major required area of innovation in portable concentrator design is the need to accomplish the sort of process control practiced in large scale units without the luxury of the tools available to large scale system designers. One particular challenge of portable concentrator design is that the devices are typically carried by the user. Since stationary oxygen concentrators are left in one site and the user uses a 50 ft tube extension to move about, the device is not nearly as close to the user under most circumstances. The portable oxygen concentrator must therefore be quieter, create less vibration, and be much more resilient to impacts, and function under constant movement and in various physical orientations. Therefore, it is necessary to design a portable oxygen concentrator that incorporates an improved mechanical design that mitigates noise and vibration while simultaneously protects the device during impact. Prior art portable oxygen concentrators fail to meet all of these design criteria and as a result, the previously available products did not meet all the needs of the users and the home medical equipment providers. These prior art concentrators failed to meet the users' needs by being too large, too loud, and operated with too much vibration to be near the user 24 hours a day. These prior art concentrators similarly failed the equipment providers due to frequent malfunctions and short service lives. Some prior art portable oxygen concentrators may need a complete compressor rebuild after only 4000 hours, which equates to roughly six months of 24/7 usage. The portable nature of the equipment exposes the devices to being dragged over rough roads, bounced around in the trunks of cars, and knocked off counter tops to impact the ground from several feet. While some prior art equipment might hold up to these high levels of abuse, they do so with added weight and reduced performance parameters such as high noise levels or lowered oxygen flow rates. Oxygen equipment used for Long Term Oxygen Therapy (LTOT) is optimally deployed for 3-5 years without any service requirements, but when there are service requirements or repairs, they must be able to be performed quickly and inexpensively. Prior art portable oxygen concentrators do not meet the objectives of fast and inexpensive repair in the event of damage. Many systems utilize adhesives to permanently bond parts together or have many components integrated into the outer housing such that replacing a damaged housing requires a nearly complete rebuild of the system. Not only do these assembly methods lead to more expensive repairs, but they limit the scope of facilities that can perform the repairs due to requirements for specific tooling and fixturing that common repair facilities would not have access to. BRIEF SUMMARY OF THE INVENTION The devices, systems, and methods of this invention each have several aspects, no single one of which is solely responsible for its desirable attributes. Without limiting the scope of this invention, its more prominent features will now be discussed briefly. In one embodiment, the invention provides a portable oxygen concentrator that incorporates novel mechanical design elements to achieve a low noise, low vibration, durable, and easily repaired design. This integrated design approach enables the portable oxygen concentrator of the preferred embodiments to meet the needs of patients and equipment providers where prior art designs have failed. The novel mechanical design elements include the assembly method of the outer housing components, low volume vibration isolation of the compressor, overlapping housing baffles, and floating column clip assembly system. Even the inventors' most robust mechanical designs may succumb to the continued abuse of some users, so the inventors designed a novel outer housing assembly system that allows for fast and inexpensive refurbishment of the concentrators so that equipment providers can minimize repair time and cost. In certain preferred embodiments, none of the internal functional components of the housing assembly are anchored to the housing panels, which allows for fast replacement as well as improved vibration and noise isolation. In a preferred embodiment the housing of the portable oxygen concentrator comprises at least four panels that snap fit together to form convoluted sound baffles for noise abatement. The outer housing panels preferably snap together with retention clips, and some of these clips may be further secured with fasteners in order to still meet the rigorous durability requirements of this class of device. In one embodiment, at least two of the panels when assembled form an inlet air plenum, and at least two panels form an outlet air plenum. In a particular aspect, the air plenum is a space between a double-walled section formed by the assembled panels. In one particular embodiment, the side panels wrap around the front and back of the device to mate together forming the inner wall of the double-walled structure. The side panels further have mirror-imaged cut-outs to form the inner air vent opening at the front of the device and the inner exhaust vent opening at the rear of the device. To form the outer wall of the intake or exhaust plenum, a convex and stylized end panel is snapped over the mated side panels forming a hollow air plenum. The opening in the end panel is offset from the opening formed in the wall section of the side panels and air flows through the space formed between the end panels and the wall section of the side panels. The path through both plenums is offset, preferably substantially non-overlapping or completely non-overlapping, to provide noise isolation. A mesh screen may be used on the inlet to keep the airways clear of debris. Between the inlet and outlet plenums there is at least one air barrier, preferably sealed to the housing panels, preferably nonridgidly with foam. An air mover, typically a cooling fan or blower, is carried by the air barrier and provides a forced air path through the barrier. In a preferred embodiment, the air barrier is a printed circuit board. In one as-built embodiment, the adsorbent bed columns are on the inlet side of the air barrier and the compressor is on the outlet side. In another embodiment, a bottom panel includes a battery mount, and the battery and panels go together such that when the battery is installed, the battery contacts and retains at least two and preferably all of the front, side and rear panels to improve the rigidity of the assembly. The battery is also preferably part of the aesthetic design of the housing. In another preferred embodiment the adsorbent columns are carried by a plurality of, preferably two, vibration/shock absorbing mounting elements. These mounting elements may be foam blocks with cutouts, such that the columns are held by the blocks and do not come into direct contact with the housing. In a particular embodiment, the foam is molded urethane. Additionally, the concentrator may contain one or more modular clips that locate the adsorbers and other components relative to each other between the blocks without making any attachments to the housing components. In a particular embodiment, the modular clips also mount the air barrier/mover, preferably a circuit board and cooling fan, to form an air dam that allows for unidirectional cooling flow that simultaneously intakes room air for the PSA cycle and exhausts waste nitrogen gas from the system without recirculation. Other elements that may be mounted with the columns in the floating assembly include an air dryer, an oxygen product accumulator, and an oxygen sensor. In a preferred embodiment, the compressor is mounted to a bracket which is in turn mounted to one or more of the housing panels, preferably a non-exterior housing panel to maintain ease of outer housing replacement. The compressor is mounted to the bracket with shock/vibration isolating elements, which in one embodiment may be overmolded rubberized mounts. The bracket is preferably mounted to the housing with a further set of shock/vibration isolating elements, providing two levels of isolation. In one embodiment, the bracket mounting elements are rubberized feet and in a particular version rubber feet with a durometer of 20 A to 60 A. In one version, the bracket is aluminum. The bracket may additionally mount one or more airflow manifolds. The bracket and the lower housing may also preferably include bump stops to limit compressor and bracket deflection during drop or impact. In one version of the invention, the compressor intake is routed through the fan ducting to ensure a supply of fresh air is always drawn into the compressor. In another embodiment an inlet air filter attaches to the compressor. The filter preferably has a tortuous air path for noise reduction, and further may be mounted with its inlet and outlet at right angles to each other for further noise reduction. Substantially all air connections to and from the filter/compressor assemble are by compliant airflow components, and in a particular embodiment molded compliant airflow components to ensure minimum force is applied to the compressor when it is located in its nominal position. In another embodiment the compressor is a two piston unit where the piston inputs are fluidly connected by a low profile compliant member. The compliant member in one version comprises one snap fit and one threaded attachment to the pistons. In various versions, the compliant member may be at least two parts of molded rubber joined together, and the member cross section is in the range of 0.02 to 0.08 square inches. In another embodiment, the portable oxygen concentrator includes a pressure sensor mount where a compliant bracket mounts the pressure sensor and in turn the bracket is mounted to the circuit card. This has the effect of eliminating the hard mounting of the sensor at its designed attachment points, improving the tolerance of the sensor to false readings due to vibration. BRIEF DESCRIPTION OF THE DRAWINGS The understanding of the following detailed description of certain preferred embodiments of the invention will be facilitated by referring to the accompanying figures. FIG. 1 shows the general elements of gas concentrators as applicable to certain embodiments of the invention. FIG. 2 shows two views of a novel concentrator according to a preferred embodiment. FIG. 3 shows an exemplary outer housing panel arrangement incorporated in the novel concentrator shown in FIG. 2 . FIG. 4 illustrates the panel snap retention clips and fasteners incorporated in the novel concentrator shown in FIG. 2 . FIG. 5 depicts the air path through the concentrator body, air barrier, and blower incorporated in the novel concentrator shown in FIG. 2 . FIG. 6 illustrates the arrangement of the compressor, mounting bracket, air filter and air input member incorporated in the novel concentrator shown in FIG. 2 . FIG. 7 shows a novel pressure sensor mount incorporated in the novel concentrators shown in FIG. 2 . FIG. 8 depicts the isolation and mounting of the adsorbent columns incorporated in the novel concentrator of FIG. 2 . FIG. 9 depicts the novel concentrator of FIG. 2 in a substantially assembled form. DETAILED DESCRIPTION OF THE INVENTION Referring to FIG. 1 , general features of a portable therapeutic gas concentrator are shown. Typically gas is drawn into the inlet through an inlet filter 1 into a compressor 2 . Compressed air is then delivered at a rate of about 3 LPM to 30 LPM (through various filters and other devices) to a gas separation section for selectively adsorbing a component of the gas. The preferred embodiments of the invention, although applicable to a variety of gas concentrator implementations, will be described in detail for the case where the inlet gas is air, and the gas separation section is based on PSA, VSA, VPSA or some combination thereof, utilizing adsorbent beds 3 which selectively adsorb nitrogen, producing oxygen rich product. A variety of gas separation section cycle types and bed arrangements are known in the art, most of which can benefit from the embodiments of the invention. Whatever the details of the gas separation section 3 , typically product gas is accumulated in a storage device 4 . Storage devices may include a tank in the traditional sense, or may be some other device effective for holding a volume of gas, such as a tube, or some other volume filled with an adsorbent to increase its holding capacity. Many modern concentrators used for therapeutic applications also include a programmable controller 5 to operate the concentrator and provide for user interface 8 and communications. Also typical are gas exhaust 6 , and delivery to patient, which often is through a conserver device 7 . Earlier portable oxygen concentrator designs were heavier and typically had an oxygen output of only around 0.1 L/lb of system weight. This low output to weight ratio was largely a result of thicker housing walls and redundant components to aid in sound reduction and vibration isolation. For a system that can be carried by the user by a shoulder strap or backpack system, a higher oxygen output to weight ratio is desired. Embodiments of the current invention increase the oxygen to weight ratio by as much as 30% over prior art concentrators while also achieving lower sound levels and increased durability. By comparison, popular existing systems have muck lower oxygen to weight ratios. The Inogen One delivered 0.75 L of oxygen and weighed 9.7 pounds for an output to weight ratio of 0.08 L/lb. The Respironics Everglo in measurements made by the inventors produced 1.05 L of oxygen at 10.2 pounds for an output to weight ratio of 0.10 L/lb. The inventors also tested the AirSep FreeStyle and measured 0.45 L of oxygen and weighs 4.3 pounds for an output to weight ratio of 0.10 L/lb. While efforts have been made to achieve greater oxygen output to weight ratios in transportable units such as continuous flow portable concentrators like the SeQual Eclipse, these units have integrated cart handles and wheels so they are not designed for the same purpose as a carried or worn concentrator and are not as likely to experience the same level of abuse as the type of concentrator designed by the inventors. As a portable concentrator shrinks to a size where it can be carried, the likelihood of significant drop and impact is greatly increased, while the requirement for component and system weight reduction is also greatly increased. System housing wall thickness may be reduced from 0.050″ down to 0.030″ or less depending on the flame rating requirements of the selected material. Further, as the volume of the concentrator shrinks from around 1200 cubic inches to less than 500 cubic inches or even 300 cubic inches, the noise, vibration, and heat generating components become ever closer to the housing walls, and inlet vents, and exhaust vents. This volume reduction necessitates improved functionality from noise mitigation and vibration mitigation designs while not allowing for additional size or weight to achieve the noise and vibration reductions. For instance the inventors tested the Invacare XPO2 and measured a high oxygen to weight ratio of 0.12 L/lb producing 0.84 L of oxygen at 7.3 pounds, but observed noise level increases to above 45 dBA as a result. As miniaturization of a portable oxygen concentrator progresses the designers are faced with ever more difficult challenges, and this disclosure details several novel design approaches that offer solutions to weight, noise, and durability requirements. The Figures depict exemplary implementations that resemble portions of an as-built novel concentrator. However it is to be understood that the details in the Figures are by way of example only and in many cases serve to illustrate a particular version of a novel concept that need not follow the exact configuration of the figures to fall within the teachings and claims of the invention. Referring to FIG. 2 a general illustration of the novel concentrator is shown. Concentrator housing 21 , battery 22 and user interface 8 are shown. The battery 22 , as depicted in the exemplary figure, forms a nearly seamless integration with the concentrator so that the battery actually forms the bottom of the concentrator and has integral overmolding that functions as an impact absorber and anti-slip footing for the concentrator. Since many drops and impacts would be taken by the bottom of the concentrator, the location of the battery provides a level of protection where damage to the battery would not stop the concentrator from functioning on external power such as AC or DC power. In addition, the sliding rails of the battery and the interlocking components that form the mating rail on the concentrator form a particularly strong and rigid area of the concentrator that allow the battery and shell of the concentrator to dissipate energy without harmfully transmitting it to the working internals of the device. The housing 21 of the concentrator is also devoid of corners and flat surfaces to further stiffen the outer shell, which allows for reduced wall thickness without reduced durability. FIGS. 3 a and 3 b depict a particular embodiment of the concentrator 21 . Base panel 33 connects to side panels 31 and 32 as well as front panel 34 and rear panel 35 as can be seen when front and rear panels 34 and 35 are attached they form an air plenum with an offset flow path, which for the exemplary panel design shown is completely non-overlapping. This offset ducting design is a significant improvement for noise isolation. A mesh screen 37 may be employed as a debris filter on the input air plenum. At least some and preferably all the side, front and rear panels are configured to overlap bottom panel 33 . When battery 22 is installed, it is configured to contact and retain the panels for added rigidity. Similarly top panel 35 also contacts all of the body panels as well. In the exemplary implementation, the air plenum space formed by the mating of panels 31 , 32 , and 34 and the similar air plenum space formed by the mating of panels 31 , 32 , and 35 create a double-walled structure where there are a plurality of connecting points, preferably eight or more. These double walled structures are similar in function to the battery attachment on the bottom of the concentrator where multiple components are mated to increase rigidity and strength while also providing for noise reduction and easy serviceability. In one particular embodiment, the side panels wrap around the front and back of the device to mate together forming the inner wall of the double-walled structure and are the two side panels and the top panel are joined with a single screw creating a three-point anchor system. The side panels further have mirror-imaged cut-outs to form the inner air vent opening at the front of the device and the inner exhaust vent opening at the rear of the device. To form the outer wall of the intake or exhaust plenum, a convex and stylized panel is installed by engaging retention clips that protrude from the convex outer panel through slots in the side panels. These clips and slots are locked into place when the panel is slid upward and further reinforced because the battery blocks the panel from disengagement in the downward direction. The opening in the end panel is offset from the opening formed in the wall section of the side panels and air flows through the space formed between the end panels and the wall section of the side panels. The path through both plenums is offset, preferably substantially non-overlapping or completely non-overlapping, to provide noise isolation by eliminating a direct path for noise to exit the device. As shown in FIGS. 4 a, b , and c panels can be attached to each other via an interference fit such as snapped together with retention clips 42 and 43 . When assembled, retention clips may be further reinforced with fastener mounts to ensure that housing holds its shape during impact to prevent undue deformation to internal components. The multitude of snapping features or other forms of interference fit type of fastening devices also allows for a reduction in the number of screws or fasteners required to assemble the concentrator since panels can be locked in place by two fasteners while maintaining strength around the entire perimeter of the panel through the snap features. This assembly method greatly reduces the assembly time and weight that would be required to have a high number of fasteners. For example, the SeQual Eclipse is a simple clamshell design that uses 10 screws to fasten the two halves together. The inventors design uses 13 screws to fasten six panels together for roughly 50% less fasteners per housing panel. A particular implementation is shown in FIGS. 4 b and 4 c . As shown in FIG. 4 b , when side panel 31 is mated with bottom panel 33 , a rail is formed along the length of the panels. When battery 22 is installed, the side panel can no longer be removed because the retention clips must be disengaged in the direction of movement that is blocked by the battery 22 . As shown in FIG. 4 c , back panel 35 attached to side panels 31 and 32 by sliding upwards to engage the retention clips 43 . When battery is installed, back panel 35 is prevented from sliding downward and thus cannot be disengaged by drop or impact. Similar arrangements as shown in the Figures also apply to the front and other side panels. Thus when battery 22 is installed, all four panels are contacted and restrained such that the panels cannot be disassembled with battery in place and structural integrity is greatly increased. Referring to FIG. 5 , the plenums formed by the assembled panels are shown. Input 52 is offset from opening 53 as output 55 is offset from opening 54 . Preferably an air barrier 50 is present within the housing between the input and output plenums, and it carries an air mover 51 , which provides the only airflow path through the barrier. In a particular embodiment barrier 50 has a plurality of functions such as an electronic circuit board and air mover 51 is a cooling fan mounted to the board 50 . The circuit board 50 is preferably sealed to the housing with foam to prevent air leakage back across the air barrier. The air flow through the body is as shown. In a particular as built embodiment, the adsorber columns are in the input side of the barrier and the compressor is in the output side of the barrier. When assembled the panels and barrier constitute a very rigid shell with controlled low noise airflow that is particularly suited to an oxygen concentrator where room air must be drawn into the system as a source of oxygen and the nitrogen rich exhaust gas must be expelled from the concentrator. It is advantageous to separate these gas streams so that there is no excess nitrogen drawn into the air inlet of the compressor. Referring to FIGS. 6 a, b and c , details of the compressor side of the novel concentrator are shown. In the exemplary version depicted, a compressor bracket 64 is mounted to panel 33 . Bracket 64 is preferably mounted to panel 33 with shock/vibration isolating elements which in the exemplary version shown are rubber feet 65 . Feet 65 preferably have a durometer between 20 A and 60 A. Compressor 62 is in turn mounted to bracket 64 with another set of shock/vibration isolation elements, providing two levels of isolation. In the exemplary version, the second set of isolators is fabricated on the bracket as overmolded rubber 64 . Panel 33 in an as-built configuration is the only housing panel with structural mounting for a vibrating component. Panel 33 is an internal panel where the battery is mounted on the underside of the panel. This panel is particularly suited for compressor mounting since the highly mass dense battery absorbs much of the transmitted vibration and prevents the transmission of vibration to the side panels that may contact the user while the device is being carried. In the inventors' prior art concentrator the compressor was mounted to a separate internal chassis that was then surrounded by housing components which led to added weight and size. The separate internal chassis of the prior art concentrator was also more susceptible to damage during drop or impact because the structure was not supported across much of its surface area. Panel 33 is fully supported by battery 22 leading to a much stronger and more resilient design. Bracket 64 may be made of aluminum for example and in the exemplary version the compressor 62 is a two piston unit. The two piston inputs are connected by low profile compliant member 63 . Element 63 in the embodiment shown is a rubber duct 630 and 631 with one snap fit and one threaded attachment to allow for vertical compliance since the compressor assemblies are pressed onto the motor shaft without a hard stop to prevent bearing loading. It may be made from two joined molded rubber pieces and the air channel preferably is between 0.02 and 0.08 sq in. The compliant member preferably has a durometer between 20 A and 70 A to prevent the flat surfaces from resonating noise. The inventors tried multiple materials and fabrication methods and achieved unacceptable results until the proper material and durometer were selected. The flat geometry of the compliant member allows for adequate cross section to prevent flow loss from the compressor while also minimizing the protrusion height from the concentrator. With the small external dimensions of a carried portable oxygen concentrator all components must be optimized to reduce space in critical directions. Prior art intake joining tubes were two hard plastic cylinders that slid internal to one another for compliance and protruded as much as twice as far from the compressor as the inventors compliant member 63 . Air filter 61 is preferably arranged with its input and output at right angles and has a tortuous air path 610 again for noise isolation. Air filter 61 is plumbed to the air blower with compliant tubing in the durometer range of 20 A to 60 A. The compressor mounting arrangement preferably also includes bump stops 66 to limit compressor deflection in the event of the concentrator being dropped or impacted. Stops 66 are placed adjacent to mounting feet 65 and compressor 62 . The stops 66 built into bracket 64 substantially prevent the compressor from colliding with delicate components like the printed circuit board or the external housing components. The bump stops 66 adjacent the mounting feet 65 also allow for softer mounting feet to be used without risk of tearing due to over deflection during drop or impact. Bracket 64 may also include mounting for beds with compliant airflow elements. When assembled, the compressor filter assembly is mounted to the housing through two layers of isolation and only connected to the rest of the system through compliant elements. Thus the assembly is highly resistant to shock and displacement while providing vibration and noise isolation. FIGS. 7 a and 7 b illustrate another embodiment of the novel concentrator. Pressure sensor 72 is designed to mount to a circuit card 50 with two fasteners. This in effect is a stiff fixed mounting that can create a torque or twist on the sensor between the mounting screws and the barbed tubing connections. Due to the shock, vibration and general motion experienced in the portable concentrator environment, this fixed mounting point induced strain can couple vibration into the sensor and can affect the quality of the measured reading. The inventors developed clip 73 which snap mounts to the sensor 72 and is a cantilever designed to mount into the fastener points intended for the sensor, while suspending the sensor itself so that it is mounted near the barbed tubing connections to relieve any strain air manifolds which again are preferably plumbed to the adsorber or stress on the body of the sensor where the delicate pressure measuring components are housed. This strain relief in effect greatly diminishes the vibration coupled into the sensor and allows for more reliable and more sensitive breath detection capabilities. Referring to FIG. 8 , the adsorber bed side of the concentrator of one embodiment is detailed. Adsorber columns 81 are supported, preferably at the top and bottom by isolation elements which fit into the housing panels such as panel 33 . These elements are in the exemplary version shown, foam blocks 82 and 83 with cutouts supporting the columns. The columns are located and held relative to each other by clips 84 . Clips 84 and blocks 82 and 83 may also carry one or more other items in addition to adsorber beds, including air dryers, an oxygen sensor, and product gas accumulator. Thus the columns and other items are floating in the housing with no hard contact to the housing at all. This arrangement greatly improves the durability and survivability of the concentrator while providing yet more noise and vibration isolation. Further in some embodiments, the columns are held in the concentrator without any screws whatsoever allowing for very simple column replacement if the zeolite is ever contaminated. In addition, noise barrier 50 and blower 51 may also be mounted in the foam blocks. The resulting assembly shown in FIG. 9 illustrates the overall concentrator assembly of one embodiment. Rigid and strong shell 21 composed of interlocking panels and locked by battery 22 has no direct contact with any interior components. The columns 81 , dryer, accumulator and all electronics 50 and fan 51 float in a foam chassis 82 and 83 on one side of the air barrier. Compressor 62 vibrates too much to use a foam chassis, so it and all directly attached components are supported by two levels of rubberized isolation, again with no direct hard attachment to the exterior housing panels. In one implementation, the only communication between the two sections is by way of compliant airflow elements such as soft plastic tubing and the like. Airflow is carefully designed to reduce noise. The result is a very hard shell, with all interior components possessing a large amount of freedom of motion relative to the shell and each other, producing an extremely damage resistant and very quiet design. The foregoing description of the preferred embodiments of the present invention has shown, described and pointed out the fundamental novel features of the invention. It will be understood that various omissions, substitutions, and changes in the form of the detail of the apparatus as illustrated as well as the uses thereof, may be made by those skilled in the art, without departing from the spirit of the invention. Consequently, the scope of the invention should not be limited to the foregoing discussions, but should be defined by appended claims.

A portable oxygen concentrator designed for medical use with a novel housing and internal component design that reduces noise and vibration while increasing durability. The improved design of the portable oxygen concentrator further facilitates easy maintenance and repair over the life of the equipment.

BACKGROUND OF THE INVENTION (1) Field of the Invention The present invention relates to an NOx sensor having the sensor element made of an oxide, a resistance of which varies in response to an NOx component in a gas to be measured, and a measuring portion for measuring a resistance variation of the sensor element and for detecting an NOx concentration in the gas to be measured. (2) Related Art Statement As a method of measuring an NOx concentration in a gas to be measured such as a fired exhaust gas from an incinerator, which includes an NOx component such as nitrogen oxide, it is known to sample a gas to be measured including an NOx component, in for example, a dust chimney, and measure an NOx concentration of the sampled gas by means of an optical measuring apparatus. However, the optical measuring apparatus is expensive, and a responsible time thereof is long since the sampling operation is necessary. In order to eliminate the drawbacks mentioned above, it has been proposed to use a direct insertion type semiconductor sensor. used recently. For example, in Japanese Patent Laid-Open Publication No. 6-222028, an NOx sensor comprising a response portion made of an oxide having a predetermined perovskite structure, and a conductivity measuring portion for measuring a conductivity of the response portion is disclosed. However, also in the direct insertion type semiconductor sensor mentioned above, there is no countermeasure for an influence of O 2 and CO components included in the gas to be measured with respect to the measured NOx concentration. Moreover, in the response portion, the resistance thereof is varied in response to the concentration of NOx (NO 2 +NO). However, if a ratio of concentration between NO 2 and NO a ratio of partial pressure between NO 2 and NO, is varied, a resistance measured by the response portion is varied even for the same NOx amount. In this case, it is reasonable to conclude that the NOx component is not selectively measured. Therefore, in the direct insertion type semiconductor sensor mentioned above, there is a drawback such that the NOx concentration in the gas to be measured cannot be selectively measured in a highly precise manner, while the semiconductor sensor is cheap and shows excellent response time as compared with the optical measuring apparatus. SUMMARY OF THE INVENTION An object of the present invention is to eliminate the drawbacks mentioned above and to provide an NOx sensor which can measure an NOx concentration in a gas to be measured selectively in a precise manner. According to the invention, the NOx sensor has the sensor element made of an oxide, a resistance of which is varied in response to an NOx component in a gas to be measured, and a measuring portion for measuring a resistance variation of the sensor element and for detecting an NOx concentration in the gas to be measured. The sensor includes a catalyst arranged at an upstream side of a flow of the gas to be measured with respect to the sensor element, which maintains the partial pressure of NO and NO 2 in an equilibrium state and removes a CO component from the gas to be measured. A heater for adjusting temperature is arranged at a position close to the sensor element, and maintained the temperatures of the sensor element and the catalyst at a constant state. An O 2 sensor is arranged at a position close to the sensor element. In the construction mentioned above, the gas to be measured passes through the catalyst which maintains the partial pressures of NO and NO 2 in an equilibrium state. The gas then the sensor element under such a condition that temperatures of the sensor element and the catalyst are maintained in a constant state by means of the heater. This arrangement makes it possible to perform a high precision measurement of NOx. That is to say, under such a condition mentioned above, a relation between a resistance measured by the sensor element and an NOx concentration is determined one by one in response to an O 2 concentration. Therefore, if the O 2 concentration is measured by the O 2 sensor for an adjustment and the NOx concentration is determined from the resistance value in response to the thus measured O 2 concentration, it is possible to perform a high precision measurement of NOx. Moreover, since the catalyst functions to remove a CO component from the gas to be measured, a CO component can be removed from the gas to be measured if the gas is contacted with the sensor element, and thus it is possible to measure the NOx concentration with no CO influence. BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a schematic view for explaining one concept of an NOx sensor according to the invention; and FIG. 2 is a graph showing a relation between a resistance value measured in the NOx sensor and an NOx concentration according to the invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic view for explaining one concept of an NOx sensor according to the invention. In FIG. 1, an NOx sensor according to the invention comprises a response portion 1 and a measuring portion 2. The response portion 1 is set in a dust chimney 3 through which a gas to be measured flows. The response portion 1 is constructed by arranging, from an upstream side of a flow of the gas to be measured, a catalyst 6, heater 7 to control temperature of response portion 1 a sensor element 8 and an O 2 sensor 9, all of which are arranged in an alumina protection tube 5 having a gas inlet portion 4. The measuring portion 2 is constructed by arranging a digital multimeter 10 for the sensor element 8, a digital multimeter 11 for the O 2 sensor 9 and a processing portion 12. A constant-potential power supply 13 is provided for the heater. The catalyst 6 is used to maintain the partial pressures of NO and NO 2 in an equilibrium state and for removing a CO component from the gas to be measured. In this embodiment, the catalyst 6 is integrally formed, but it is possible to form the catalyst 6 separately corresponding to the objects mentioned above, respectively. In the case of constructing the catalyst 6 separately, not only the same kinds of catalysts but also other kinds of catalysts may be used for the catalyst 6. In order to achieve the objects mentioned above, it is preferred to use precious metals or oxides as the catalyst 6. As the precious metals, it is preferred to use platinum, rhodium or gold. As the oxides, it is preferred to use manganese oxide, cobalt oxide or tin oxide. The heater 7 is used for maintaining the sensor element 8 and the catalyst 6 at a constant temperature even if a temperature of the gas to be measured varies. Therefore, it is preferred to arrange heater 7 between the sensor element 8 and the catalyst 6. The sensor element 8 is made of an oxide, the resistance of which varies in response to an NOx component, if the oxide is contacted to the gas to be measured including an NOx component. As the oxide mentioned above, it is preferred to use metal oxide semiconductors. Among them, it is further preferred to use SnO 2 , TiO 2 or In 2 O 3 . If the sensor element 8 is made of the oxides mentioned above, it is possible to use the same structure, shape and so on as those of the known sensor element. In the NOx sensor according to the invention having the construction mentioned above, an NOx concentration measuring is performed as follows. At first, the gas to be measured is supplied from the gas inlet portion 4 into the response portion 1 under such a condition that temperatures of the sensor element 8 and the catalyst 6 are maintained constantly by means of heater 7. The thus supplied gas is passed through the catalyst 6. When the gas to be measured is passed through the catalyst 6, the partial pressures of NO and NO 2 are forced to achieve equilibrium and a CO component in the gas to be measured is burnt. Therefore, the gas to be measured, in which the partial pressure ratio of NO/NO 2 is at an equilibrium state and a CO component is removed, can be contacted with the sensor element 8. In this case, a relation between a resistance of the sensor element 8 and NOx concentration can be determined directly if an oxygen concentration is constant. However, the oxygen concentration in the gas to be measured is not constant in practice. Therefore, in the present invention, the O 2 sensor 9 is arranged in the response portion 1 so as to always measure the oxygen concentration, and the NOx concentration is obtained from a relation between the resistance of the sensor element 8 based on the oxygen concentration and the NOx concentration. As one example, a relation between resistances at the oxygen concentrations of 1% and 20% and NOx concentrations, which is based on the results in the following experiment 1 of sample Nos. 1-10, is shown by FIG. 2. In FIG. 2, the relation is shown only at the oxygen concentrations 1% and 20%. However, if relations at the other oxygen concentrations are measured beforehand, the NOx concentration can be measured by using the relation corresponding to the oxygen concentration measured by the O 2 sensor 9. As a result, the NOx concentration can be measured without being affected by the partial pressure ratio of NO/NO 2 , the O 2 component, the CO component and the atmospheric temperature. Hereinafter, an actual embodiment will be explained. Experiment 1 As shown in FIG. 1, the NOx sensor was constructed by arranging the catalyst 6, the heater 7, the sensor element 8 and the O 2 sensor 9. The sensor element 8 was produced according to the following steps. At first, tin chloride was subjected to a hydrolysis by using an ammonia solution to obtain a dissolved solution. Then, the dissolved solution was separated by a filtering. After that, the thus separated dissolved solution was subjected to a pyrolysis at 600° C. for 2 hours to synthesize tin oxide powders. Then, the thus obtained tin oxide powders were mixed in a wet state in ethanol solution for 10 hours by using zirconia balls to obtain an tin oxide slurry for dipping. As a body of the sensor element 8, use was made of an alumina tube having a diameter of 1.5 mm and a length of 5 mm to which a platinum wire having a diameter of 3 mm was secured. Then, the body was dipped in the tin oxide slurry. After that, the thus dipped body was fired at 800° C. for 2 hours to obtain the sensor element 8. Moreover, the heater for a temperature adjustment 7 was produced by working a platinum wire into a coil shape. Further, platinum powders were arranged on a cordierite honeycomb carrier by a wash-coat method. After that, the cordierite honeycomb carrier was fired at 500° C. for 2 hours to obtain the catalyst 6 which functions to control the partial pressure ratio of NO/NO 2 and remove the CO component. As the O 2 sensor 9, use was made of a zirconia O 2 sensor. The measurement was performed in such a manner that a resistance of the sensor element 8 and a current of the O 2 sensor 9 were detected respectively by the digital multimeters 10 and 11 via the platinum lead wires. As shown in the following Table 1, the gas to be measured including NOx such as NO 2 and NO having a predetermined concentration as well as the other components such as O 2 , CO 2 , H 2 O, CO and N 2 was prepared. In this case, a total of all components was 100%. Then, the thus prepared gas was flowed, under such a condition that a temperature of the sensor element 8 was maintained constantly, to measure a resistance of the sensor element 8 by using the NOx sensor having the construction mentioned above. Moreover, as a comparative example, a resistance of the sensor element 8 was measured in the same manner as the example mentioned above except that a temperature of the sensor element 8 was not controlled and the catalyst 6 was not used. The results are shown in Table 1. TABLE 1__________________________________________________________________________ Sensor Atmosphere CO temperature temperature NO/NO.sub.2 burning NO.sub.2 NO NOx O.sub.2 CO.sub.2 H.sub.2 O CO ResistanceSample No. (°C.) (°C.) catalyst catalyst (ppm) (ppm) (ppm) (%) (%) (%) (ppm) N.sub.2 (kΩ)__________________________________________________________________________Exampleof PresentInvention 1 500 400 Pt Pt 200 800 1000 1 10 7 0 remainder 76.1 2 500 400 Pt Pt 100 400 500 1 10 7 0 remainder 72.0 3 500 400 Pt Pt 50 200 250 1 10 7 0 remainder 66.5 4 500 400 Pt Pt 10 40 50 1 10 7 0 remainder 41.2 5 500 400 Pt Pt 2 8 10 1 10 7 0 remainder 10.0 6 500 400 Pt Pt 200 800 1000 20 10 7 0 remainder 169.1 7 500 400 Pt Pt 100 400 500 20 10 7 0 remainder 161.0 8 500 400 Pt Pt 50 200 250 20 10 7 0 remainder 153.2 9 500 400 Pt Pt 10 40 50 20 10 7 0 remainder 112.310 500 400 Pt Pt 2 8 10 20 10 7 0 remainder 38.011 500 400 Pt Pt 100 400 500 1 10 7 1000 remainder 71.812 500 400 Pt Pt 50 200 250 1 10 7 1000 remainder 66.313 500 400 Pt Pt 200 800 1000 20 10 7 1000 remainder 168.814 500 400 Pt Pt 100 400 500 1 10 7 0 remainder 72.115 500 400 Pt Pt 100 400 500 1 10 20 0 remainder 72.016 500 400 Pt Pt 40 10 50 1 10 7 0 remainder 41.017 500 400 Pt Pt 800 200 1000 1 10 7 0 remainder 76.018 500 400 Pt Pt 800 200 1000 20 10 7 0 remainder 170.019 500 300 Pt Pt 200 800 1000 1 10 7 0 remainder 76.020 500 300 Pt Pt 200 800 1000 20 10 7 0 remainder 169.721 500 300 Pt Pt 800 200 1000 1 10 7 0 remainder 76.2ComparativeExample 1 not control 400 None None 200 800 1000 1 10 7 0 remainder 462.3 2 not control 400 None None 200 800 1000 1 10 7 1000 remainder 91.2 3 not control 400 None None 200 800 1000 20 10 7 0 remainder 997.5 4 not control 400 None None 800 200 1000 1 10 7 0 remainder 534.8 5 not control 300 None None 200 800 1000 1 10 7 0 remainder 1676__________________________________________________________________________ From the results shown in Table 1, when the oxygen concentration is constant, it is understood that the same resistance can be obtained consistently in the examples according to the invention even if a concentration ratio between NO 2 and NO is varied and also the CO component is included. On the other hand, it is understood that the resistances are largely varied in the comparative examples. Therefore, in the examples according to the invention, if the NOx concentration is measured from the resistance, the constant NOx concentration can be obtained consistently even if a concentration ratio between NO 2 and NO is varied and also the CO component is included. Accordingly, the precise measurement of NOx can be performed. On the other hand, in the comparative examples, even if the NOx concentration is measured from the resistance, the constant NOx concentration cannot be obtained, and thus the measurement accuracy is diminished. Experiment 2 The NOx concentration measuring was performed in the same manner as that of the experiment 1 by using the substantially same NOx sensor as that of the experiment 1 except that an indium oxide obtained by subjecting a nitrate to a pyrolysis at 600° C. for 2 hours was used as a material of the sensor element 8, a manganese oxide was used as the catalyst 6 for controlling the partial pressure ratio of NO/NO 2 , and a tin oxide was used as the catalyst 6 for removing the CO component. The results are shown in Table 2. TABLE 2__________________________________________________________________________ Sensor Atmosphere CO temperature temperature NO/NO.sub.2 burning NO.sub.2 NO NOx O.sub.2 CO.sub.2 H.sub.2 O CO ResistanceSample No. (°C.) (°C.) catalyst catalyst (ppm) (ppm) (ppm) (%) (%) (%) (ppm) N.sub.2 (kΩ)__________________________________________________________________________Exampleof PresentInvention 1 500 400 Mn.sub.3 O.sub.4 SnO.sub.2 200 800 1000 1 10 7 0 remainder 3.54 2 500 400 Mn.sub.3 O.sub.4 SnO.sub.2 100 400 500 1 10 7 0 remainder 3.11 3 500 400 Mn.sub.3 O.sub.4 SnO.sub.2 50 200 250 1 10 7 0 remainder 2.23 4 500 400 Mn.sub.3 O.sub.4 SnO.sub.2 10 40 50 1 10 7 0 remainder 1.10 5 500 400 Mn.sub.3 O.sub.4 SnO.sub.2 2 8 10 1 10 7 0 remainder 0.21 6 500 400 Mn.sub.3 O.sub.4 SnO.sub.2 200 800 1000 20 10 7 0 remainder 9.02 7 500 400 Mn.sub.3 O.sub.4 SnO.sub.2 100 400 500 20 10 7 0 remainder 8.34 8 500 400 Mn.sub.3 O.sub.4 SnO.sub.2 50 200 250 20 10 7 0 remainder 7.22 9 500 400 Mn.sub.3 O.sub.4 SnO.sub.2 10 40 50 20 10 7 0 remainder 3.1210 500 400 Mn.sub.3 O.sub.4 SnO.sub.2 2 8 10 20 10 7 0 remainder 0.6311 500 400 Mn.sub.3 O.sub.4 SnO.sub.2 100 400 500 1 10 7 1000 remainder 3.1312 500 400 Mn.sub.3 O.sub.4 SnO.sub.2 50 200 250 1 10 7 1000 remainder 2.2413 500 400 Mn.sub.3 O.sub.4 SnO.sub.2 200 800 1000 20 10 7 1000 remainder 9.0414 500 400 Mn.sub.3 O.sub.4 SnO.sub.2 100 400 500 1 10 7 0 remainder 3.1115 500 400 Mn.sub.3 O.sub.4 SnO.sub.2 100 400 500 1 10 20 0 remainder 3.1216 500 400 Mn.sub.3 O.sub.4 SnO.sub.2 40 10 50 1 10 7 0 remainder 1.1217 500 400 Mn.sub.3 O.sub.4 SnO.sub.2 800 200 1000 1 10 7 0 remainder 3.5618 500 400 Mn.sub.3 O.sub.4 SnO.sub.2 800 200 1000 20 10 7 0 remainder 9.0019 500 300 Mn.sub.3 O.sub.4 SnO.sub.2 200 800 1000 1 10 7 0 remainder 3.5520 500 300 Mn.sub.3 O.sub.4 SnO.sub.2 200 800 1000 20 10 7 0 remainder 9.0121 500 300 Mn.sub.3 O.sub.4 SnO.sub.2 800 200 1000 1 10 7 0 remainder 3.56ComparativeExample 1 not control 400 None None 200 800 1000 1 10 7 0 remainder 18.54 2 not control 400 None None 200 800 1000 1 10 7 1000 remainder 5.50 3 not control 400 None None 200 800 1000 20 10 7 0 remainder 46.98 4 not control 400 None None 800 200 1000 1 10 7 0 remainder 24.38 5 not control 300 None None 200 800 1000 1 10 7 0 remainder 35.46__________________________________________________________________________ Also from the results shown in Table 2, when the oxygen concentration is constant, it is understood that the same resistance can be obtained consistently in the examples according to the invention even if a concentration ratio between NO 2 and NO is varied and also the CO component is included. On the other hand, it is understood that the resistances are largely varied in the comparative examples. Experiment 3 The NOx concentration measuring was performed in the same manner as that of the experiment 1 by using the substantially same NOx sensor as that of the experiment 1 except that a titanium oxide obtained by subjecting a sulfate to a pyrolysis at 800° C. for 1 hour was used as a material of the sensor element 8, a cobalt oxide was used as the catalyst 6 for controlling the partial pressure ratio of NO/NO 2 , and gold was used as the catalyst 6 for removing the CO component. The results are shown in Table 3. TABLE 3__________________________________________________________________________ Sensor Atmosphere CO temperature temperature NO/NO.sub.2 burning NO.sub.2 NO NOx O.sub.2 CO.sub.2 H.sub.2 O CO ResistanceSample No. (°C.) (°C.) catalyst catalyst (ppm) (ppm) (ppm) (%) (%) (%) (ppm) N.sub.2 (kΩ)__________________________________________________________________________Exampleof PresentInvention 1 500 400 Co.sub.3 O.sub.4 Au 200 800 1000 1 10 7 0 remainder 23611 2 500 400 Co.sub.3 O.sub.4 Au 100 400 500 1 10 7 0 remainder 19872 3 500 400 Co.sub.3 O.sub.4 Au 50 200 250 1 10 7 0 remainder 15181 4 500 400 Co.sub.3 O.sub.4 Au 10 40 50 1 10 7 0 remainder 6429 5 500 400 Co.sub.3 O.sub.4 Au 2 8 10 1 10 7 0 remainder 760 6 500 400 Co.sub.3 O.sub.4 Au 200 800 1000 20 10 7 0 remainder 56262 7 500 400 Co.sub.3 O.sub.4 Au 100 400 500 20 10 7 0 remainder 47351 8 500 400 Co.sub.3 O.sub.4 Au 50 200 250 20 10 7 0 remainder 36201 9 500 400 Co.sub.3 O.sub.4 Au 10 40 50 20 10 7 0 remainder 1521010 500 400 Co.sub.3 O.sub.4 Au 2 8 10 20 10 7 0 remainder 181111 500 400 Co.sub.3 O.sub.4 Au 100 400 500 1 10 7 1000 remainder 1986912 500 400 Co.sub.3 O.sub.4 Au 50 200 250 1 10 7 1000 remainder 1518213 500 400 Co.sub.3 O.sub.4 Au 200 800 1000 20 10 7 1000 remainder 5625914 500 400 Co.sub.3 O.sub.4 Au 100 400 500 1 10 7 0 remainder 1987015 500 400 Co.sub.3 O.sub.4 Au 100 400 500 1 10 20 0 remainder 1987416 500 400 Co.sub.3 O.sub.4 Au 40 10 50 1 10 7 0 remainder 643017 500 400 Co.sub.3 O.sub.4 Au 800 200 1000 1 10 7 0 remainder 2361318 500 400 Co.sub.3 O.sub.4 Au 800 200 1000 20 10 7 0 remainder 5625919 500 300 Co.sub.3 O.sub.4 Au 200 800 1000 1 10 7 0 remainder 2361020 500 300 Co.sub.3 O.sub.4 Au 200 800 1000 20 10 7 0 remainder 5626321 500 300 Co.sub.3 O.sub.4 Au 800 200 1000 1 10 7 0 remainder 23616ComparativeExample 1 not control 400 None None 200 800 1000 1 10 7 0 remainder 35125 2 not control 400 None None 200 800 1000 1 10 7 1000 remainder 3864 3 not control 400 None None 200 800 1000 20 10 7 0 remainder 87540 4 not control 400 None None 800 200 1000 1 10 7 0 remainder 98734 5 not control 300 None None 200 800 1000 1 10 7 0 remainder 78654__________________________________________________________________________ Also from the results shown in Table 3, when the oxygen concentration is constant, it is understood that the same resistance can be obtained consistently in the examples according to the invention even if a concentration ratio between NO 2 and NO is varied and also the CO component is included. On the other hand, it is understood that the resistances are largely varied in the comparative example. As clearly understood from the above, according to the invention, since the gas to be measured passed through the catalyst which makes a partial pressure ratio of NO/NO 2 reach an equilibrium state is contacted to the sensor element under such a condition that temperatures of the sensor element and the catalyst are maintained in a constant state by means of the heater, it is possible to perform a high precision measurement. That is to say, under such a condition mentioned above, a relation between a resistance measured by the sensor element and an NOx concentration is determined directly in response to an O 2 concentration. Therefore, if the O 2 concentration is measured by the O 2 sensor for an adjustment and the NOx concentration is determined from the resistance value in response to the thus measured O 2 concentration, it is possible to perform a high precision measurement. Moreover, since the catalyst functions to remove a CO component from the gas to be measured, a CO component can be removed from the gas to be measured if the gas is contacted with the sensor element, and thus it is possible to measure the NOx concentration with no CO influence.

An NOx sensor has the sensor element made of an oxide, the resistance of which is varied in response to an NOx component in a gas to be measured, and a measuring portion for measuring a resistance variation of the sensor element and for detecting an NOx concentration in the gas to be measured. A catalyst is arranged at an upstream side of a flow of the gas to be measured with respect reach to the sensor element, which makes a partial pressure ratio of NO/NO 2 reach to an equilibrium state and removes a CO component from the gas to be measured. A heater for adjusting a temperature is arranged at a position close to the sensor element, which maintains temperatures of the sensor element and the catalyst constant. An O 2 sensor is arranged at a position close to the sensor element so that the measuring portion can detect accurately the concentration of Nox in the measurement gas by reference to the resistance of the sensor element.

TECHNICAL FIELD The invention concerns a process and means for cutting hard objects or materials without cutting softer objects or materials. BACKGROUND OF THE INVENTION The prior art describes cutting means such as saws to which a periodic motion is imparted, generally by an electric motor, thus enabling such means to cut or convert various types of materials or objects. Particular examples of this type of machine are circular saws and jigsaws, in which the cutting element consists respectively of a toothed disk driven in rotation about a stationary axis, or of a toothed blade driven in an alternating linear motion. However useful such equipment may be, it has a number of drawbacks, notably that of cutting any material that is applied to or pushed against the cutting element, regardless of the hardness or softness of that material. In other words, if the user of such equipment is clumsy or inattentive, even for a few seconds, he runs the risk of seriously injuring himself if the cutting element comes into contact with a part of his body. The process and means of the invention eliminate or at least considerably reduce such risks by effectively cutting hard materials or objects without cutting or damaging softer materials or objects such as human flesh. SUMMARY OF THE INVENTION For this purpose, the process of the invention requires that two combined motions be imparted to the cutting element. One motion has a relatively long period and is oriented in a certain direction of cut. The second motion, in the same cutting direction, is an oscillating motion with a smaller period than that of the first motion. In this way, the risks and dangers associated with the use of cutting mechanisms are considerably reduced. Furthermore, the lifetime of the machine is prolonged by the fact that the cutting element undergoes uniform wear and is not subject to overheating. One embodiment of the invention provides more specifically that a relatively slow, alternating, linear movement of high amplitude is communicated to the cutting element along a given cutting axis, while, along the same cutting axis, a more rapid vibrating motion of lower amplitude is communicated to the cutting element as the latter occupies a series of positions in the course of its alternating, linear motion. An equally attractive embodiment provides that a relatively slow movement of rotation about a fixed axis is communicated to the cutting element, while a more rapid vibrating movement of relatively smaller amplitude is imparted to the cutting element in the same cutting direction as the cutting element revolves through a series of successive positions. It should be noted that, regardless of the embodiment used, the movements to which the cutting element is subjected are less violent and abrupt than with known circular or linear drive mechanisms, with the result that the cutting element receives less wear, thus facilitating its maintenance and extending its useful life. Because the process of the invention is particularly applicable to jigsaws and circular saws, the means of the invention naturally comprise, in addition to a cutting element such as a saw blade, specific drive means applied to one or the other of these two types of saw. The result is a cutting mechanism that is both effective and safe, whereas with known means of this type, in which a relatively rapid periodic movement of greater or lesser amplitude is imparted to the blade, the resulting cut is either dangerous or ineffective for hard materials such as wood. BRIEF DESCRIPTION OF THE FIGURES The process and means of the invention will be more clearly apparent from the following description, made with reference to the accompanying drawings, in which: FIG. 1 is a schematic interior elevational view of one embodiment of the invention. FIG. 2 illustrates in greater detail the gears and connecting parts of the means depicted in FIG. 1. FIG. 3 is a schematic interior elevational view of a variant of the invention. FIG. 4 more specifically illustrates the position of the various gears and the drive shaft of the means illustrated in FIG. 3. DETAILED DESCRIPTION OF THE INVENTION FIGS. 1 and 2 illustrate cutting means of the jigsaw type produced in accordance with the invention. The means shown, designated overall by the numeral 1, comprise a body or housing 2 within which are positioned a support frame 31 capable of moving in translation with respect to housing 2, essentially along the axis 25 of a toothed blade 3, and drive and connection means required to impart to said blade periodic motions of different periods by means of a motor 4, preferentially electric, fastened to frame 31. In the interest of clarity, all of the means making up the mechanism of the invention will be described. Motor 4 drives in rotation an output shaft 14 that passes through a gear 8 to which it is attached. The end of said shaft 14 opposite the motor is extended in the form of a stub 10 mounted slightly off-center with respect to the axis of rotation 14a of shaft 14, onto which it is fastened. Stub 10 passes through a rod 15 that is integral with the blade. The passage is provided by an opening 26 that is elongated on an axis 27 that is essentially perpendicular to axis 25 of the blade and to shaft 14. It will be understood that blade 3 constitutes the cutting element of the mechanism. Rod 15 extends along the axis of said blade into the body of the mechanism. FIGS. 1 and 2 both show that gear 8 meshes with a gear 6 that transmits movement to a gear 7 through a shaft 11 and keys 12, 13. Said shaft 11 is set into frame 31 at either end, and passes through gears 6 and 7 and rod 15 (through an opening 22 that is elongated in a direction essentially parallel to the direction of axis 25 of the blade). Shaft 11 is parallel to shaft 14 and is stationary in translation but free to rotate. It will be noted that gear 7 meshes with another gear 5 which is itself connected on either side to two gears 9, 9' by means of a shaft 16 and two keys 20, 21. Shaft 16 extends between gears 9, 9' in a direction parallel to shafts 11 and 14. In addition to gear 5, shaft 16 traverses rod 15 through an opening 23 that is elongated in a direction that is essentially parallel to the direction of axis 25 of the blade. Gears 9, 9' are each provided with an eccentric stub 19, 19' that extends parallel to axis 16a of shaft 16. In order to guide the eccentric motion produced, each stub passes through a stationary part 32, 33 of housing 2, making use of openings 34, 35, which are elongated in a direction essentially parallel to axis 27 discussed above. It will be noted that stubs 19 and 19' are mounted further off-center with respect to shaft 16 than is stub 10 with respect to motor output shaft 14. Now that the principal means for driving the blade have been described, it will be noted that in FIG. 1 the movable part of the mechanism, supported by frame 31, has been marked with cross-hatches. Eccentric stubs 19, 19' provide the connection between stationary housing 2 and the set of means that make up the movable portion. They do this by being stationary in translation but free to rotate within parts 32 and 33 of said housing. In order to guide said mobile portion in its displacements parallel to axis 25, pairs of slides 29, 30 are provided on frame 31 and housing 2. In addition, rollers 28a, 28b, 28c, 28d, or equivalent means, may advantageously guide the rod 15 that drives the blade, which protrudes from housing 2 through an opening 24. FIGS. 3 and 4 illustrate a variant of the means of the invention in the form of a circular saw. As with the first embodiment, only a portion of the means for driving and controlling the blade is covered by the invention. However, in the interest of clarity, all of the means contributing to the operation of said circular saw will be described in detail. Like the mechanism illustrated in FIGS. 1 and 2, these means include a housing 200; various gear 300, 310-350; connecting shafts 400, 410 . . . 430; keys 800, 810, . . . 830; an electric motor providing rotational power; and a cutting element 700 in the form of a toothed disk. This mechanism is further provided with ball bearings 900, 910 . . . 930 mounted on the shafts or on eccentric stub 500. FIGS. 3 and 4 show clearly that motor 600, which is mounted so as to be stationary within housing 200, imparts rotational motion to an output shaft 420, which transmits said rotational motion to two gears 300 and 310. Each of the latter is locked onto the shaft with a key 830, 820. Gear 300 meshes with another gear 330, while wheel 310 meshes with gear 320. Onto the latter gear is mounted a shaft 400 which extends parallel to shaft 420. Eccentric stub 500 is locked onto shaft 400. Said eccentric stub 500 extends into a ball bearing 910 mounted on an L-shaped shaft 430 that extends beyond housing 200 along an axis 40 that is parallel (or coextensive) with that of shaft 420. Shaft 430 is further protected by another ball bearing 900 mounted within the wall of said housing. The protruding end 431 of shaft 430 imparts rotational motion to cutting disk 700. Returning now to the gearing, it will be noted that gear 330, which is already connected to gear 300, transmits rotational motion to a gear wheel 350 by means of a shaft 410, parallel to shaft 420, and of keys 800 and 810, mounted on gears 330 and 350 respectively. Shaft 410, which is free to rotate, is set at either end into stationary sections 250, 251 of housing 200. FIG. 3 in particular shows that gear 350 meshes with another gear 340, traversed by shafts 400 and 420, which were discussed above. Said shafts pass through ball bearings mounted on said gear 340 and designated 920 and 930 respectively. Referring now to FIG. 4, it can been that shaft 430, which drives the cutting disk, is forked at the point at which it meets eccentric stub 500. The two prongs 451, 452 of the fork contain ball bearing 910, into which extends eccentric stub 500. With two examples of variants of the means of the invention having been described, the functioning of those examples will now be discussed. In the examples, two periodic motions occurring in a single cutting direction but having different periods are combined and communicated to a cutting element (or possibly other equivalent means) designed to cut hard objects or materials without cutting or damaging softer objects or materials. More specifically, the parts making up the jigsaw illustrated in FIGS. 1 and 2 act in such a way that it is possible to communicate to blade 3, in the cutting direction shown by axis 25, a relatively slow, alternating linear movement of high amplitude and a more rapid vibrational motion of low amplitude. The latter movement is produced in a series of positions occupied by the blade in the course of its alternating linear motion. The two movements are combined as follows. (a) Osillatory or vibratory motion of the saw blade. Eccentric stub 10 is locked onto shaft 14, which in turn is controlled by motor 4. Said stub 10 drives rod 15, and therefore blade 3, in a rapid, longitudinal reciprocal motion of low amplitude. Said motion occurs essentially within axis 25. It will be noted that, for this purpose, rod 15 is guided by two shafts 11 and 16, which pass through elongated openings 22 and 23, and by rollers 28a, 28b, 28c, and 28d. (b) Reciprocal motion of the blade and of the entire movable portion of the mechanism. Through a system of reduction gears 8-6, 7-5, wheels 9, 9', each carrying an eccentric stub 19, 19', revolve slowly about the common axis 36 of the stubs, thereby communicating a relatively slow and broad reciprocal motion along axis 25 to the entire movable portion of the mechanism, and particularly blade 3. With reference to the circular saw variant of the invention, it will be noted that instead of imparting an alternating linear motion to the cutting element, the means of the invention communicate to the latter, in the cutting direction shown by arrow 50, a relatively slow rotational movement about a stationary axis 40, combined with a more rapid vibratory motion of relatively low amplitude and occurring in the same cutting direction. Said vibratory motion is produced as the cutting element, i.e., toothed disk 700, occupies a series of positions in the course of its rotational motion. The two combined movements are produced as follows. (a) Oscillatory or vibratory motion of disk. Gear 310, driven by shaft 420 and motor 600, produces higher revolutions in gear 320, which carries shaft 400 and its eccentric stub 500. Surrounding the latter is a ball bearing 910. Said stub 500 imparts to L-shaped shaft 430 a relatively rapid oscillatory motion about main axis 40. Said motion is transmitted by shaft 430 to the teeth of disk 700. (b) Rotation of disk. Gear 300 is also connected to shaft 420 and driven by motor 600. Through reduction gears 330, 350, and 340, said gear 300 drives shaft 430 in a rotational motion that is relatively slow with respect to the foregoing vibratory motion. Disk 700 is therefore driven about fixed axis 40 in a combined movement of relatively slow rotation and much more rapid oscillation, with both movements occurring in a single cutting direction 50. The invention is naturally not limited to the embodiments that have been described in detail. Rather, it embraces all possible variants that might include equivalent means. In particular, a cam system, vibrator, or electro-pneumatic system might complement or replace the eccentric stub in producing the vibratory or oscillatory movement of the cutting element.

The invention concerns a process and apparatus for cutting hard objects or materials without cutting softer objects or materials. In the invention, a transmission imparts to the cutting element a relatively slow periodic motion that is combined with a second, more rapid periodic motion consisting of relatively low-amplitude vibrations, with the second motion being imparted by oscillation. The invention may be applied to jigsaws and circular saws.

This invention is a divisional application of U.S. patent application Ser. No. 10/649,288 filed Aug. 27, 2003, now U.S. Pat. No. 7,160,574, and claims the benefit of priority to U.S. Provisional Patent Application 60/406,602 filed Aug. 28, 2002. FIELD OF INVENTION This invention relates to piping repair and restoration, and in particular to methods, systems and apparatus for cleaning and providing barrier protective coatings to the interior walls of small metal and plastic type pipes such as drain lines, hot water lines, cold water lines, potable water lines, natural gas lines, HVAC piping systems, drain lines, and fire sprinkler system lines, and the like, that are used in multi-unit residential buildings, office buildings, commercial buildings, and single family homes, and the like. BACKGROUND AND PRIOR ART Large piping systems such as those used in commercial buildings, apartment buildings, condominiums, as well as homes and the like that have a broad base of users commonly develop problems with their pipes such as their water and plumbing pipes, and the like. These problems can include leaks caused by pipe corrosion and erosion, as well as blockage from mineral deposits that develop over time where materials build up directly inside the pipes. Presently when a failure in a piping system occurs the repair method may involve a number of applications. Those repair applications may involve a specific repair to the area of failure such as replacing that section of pipe or the use of a clamping devise and a gasket. In some cases the complete piping system of the building may need to be replaced. In the case of pipes where the water flow has been impeded by rust build up or by a deposit build up such as calcium and other minerals, various methods for the removal of the rust or other build up have been used. However the damage caused by the rust or from other deposits to the pipe wall cannot be repaired unless the pipe is replaced. Traditional techniques to correct for the corrosion, leakage and blockage problems have included replacing some or all of a building's pipes. In addition to the large expense for the cost of the new pipes, additional problems with replacing the pipes include the immense labor and construction costs that must be incurred for these projects. Most piping systems are located behind finished walls or ceilings, under floors, in concrete or underground. From a practical viewpoint simply getting to the problem area of the pipe to make the repair can create the largest problem. Getting to the pipe for making repairs can require tearing up the building, cutting concrete and/or having to dig holes through floors, the foundation or the ground. These labor intensive repair projects can include substantial demolition of a buildings walls and floors to access the existing piping systems. For example, tearing out the interior walls to access the pipes is an expected result of the demolition. Once the walls and floors have been opened, then the old pipes are usually pulled out and thrown out as scrap, which is then followed by replacement with new pipes. These prior techniques do little if nothing to reuse, refix, or recycle the old pipes. In addition, there are usually substantial costs for removing the debris and old pipes from the worksite. With these projects both the cost of new pipes and the additional labor to install these pipes are required expenditures. Further, there are additional added costs for the materials and labor to replumb these new pipes along with the necessary wall and floor repairs that must be made to clean up for the demolition effects. For example, getting at and fixing a pipe behind drywall is not completing the repair project. The drywall must also be repaired, and just the drywall type repairs can be extremely costly. Additional expenses related to the repair or replacement of an existing piping system will vary depending primarily on the location of the pipe, the building finishes surrounding the pipe and the presence of hazardous materials such as asbestos encapsulating the pipe. Furthermore, these prior known techniques for making piping repair take considerable amounts of time that can include many months or more to be completed which results in lost revenue from tenants and occupants of commercial type buildings since tenants cannot use the buildings until these projects are completed. Finally, the current pipe repair techniques are usually only temporary. Even after encountering the cost to repair the pipe, the cost and inconvenience of tearing up walls or grounds and if a revenue property the lost revenue associated with the repair or replacement, the new pipe will still be subject to the corrosive effects of fluids such as water that passes through the pipes. Over the years many attempts have been proposed for cleaning water type pipes with chemical cleaning solutions. See for example, U.S. Pat. Nos. 5,045,352 to Mueller; 5,800,629 to Ludwig et al.; 5,915,395 to Smith; and 6,345,632 to Ludwig et al. However, all of these systems require the use of chemical solutions such as liquid acids, chlorine, and the like, that must be run through the pipes as a prerequisite prior to any coating of the pipes. The National Sanitation Foundation (NSF) specifically does not allow the use of any chemical agent solutions for use with cleaning potable water piping systems. Thus, these systems cannot be legally used in the United States for cleaning out water piping systems. Other systems have been proposed that use dry particulate materials as a cleaning agent that is sprayed from mobile devices that travel through or around the pipes. See U.S. Pat. Nos. 4,314,427 to Stolz; and 5,085,016 to Rose. However, these traveling devices require large diameter pipes to be operational and cannot be used inside of pipes that are less than approximately 6 inches in diameter, and would not be able to travel around narrow bends. Thus, these devices cannot be used in small diameter pipes found in potable water piping systems that also have sharp and narrow bends. The proposed systems and devices referenced above generally require sectioning a small pipe length for cleaning and coating type applications, or limiting the application to generally straight elongated pipe lengths. For large building such as multistory applications, the time and cost to section off various piping sections would be cost prohibitive. None of the prior art is known to be able to service an entire building's water type piping system at one time in one complete operation. Thus, the need exists for solutions to the above problems with fixing existing piping systems in buildings. SUMMARY OF THE INVENTION A primary objective of the invention is to provide methods, systems and devices for repairing interior walls of pipes in buildings without having to physically remove and replace the pipes. A secondary objective of the invention is to provide methods, systems and devices for repairing interior walls of pipes by initially cleaning the interior walls of the pipes. A third objective of the invention is to provide methods, systems and devices for repairing interior walls of pipes by applying a corrosion protection barrier coating to the interior walls of the pipes. A fourth objective of the invention is to provide methods, systems and devices for repairing interior walls of pipes in buildings in a cost effective and efficient manner. A fifth objective of the invention is to provide methods, systems and devices for repairing interior walls of pipes which is applicable to small diameter piping systems from approximately ⅜″ to approximately 6″ in piping systems made of various materials such as galvanized steel, black steel, lead, brass, copper or other materials such as composites including plastics, as an alternative to pipe replacement. A sixth objective of the invention is to provide methods, systems and devices for repairing interior walls of pipes which is applied to pipes, “in place” or insitu minimizing the need for opening up walls, ceilings, or grounds. A seventh objective of the invention is to provide methods, systems and devices for repairing interior walls of pipes which minimizes the disturbance of asbestos lined piping or walls/ceilings that can also contain lead based paint or other harmful materials. An eighth objective of the invention is to provide methods, systems and devices for repairing interior walls of pipes where once the existing piping system is restored with a durable epoxy barrier coating the common effects of corrosion from water passing through the pipes will be delayed if not stopped entirely. A ninth objective of the invention is to provide methods, systems and devices for repairing interior walls of pipes to clean out blockage where once the existing piping system is restored, users will experience an increase in the flow of water, which reduces the energy cost to transport the water. Additionally, the barrier epoxy coating being applied to the interior walls of the pipes can create enhanced hydraulic capabilities again giving greater flow with reduced energy costs. A tenth objective of the invention is to provide methods, systems and devices for repairing interior walls of pipes where customers benefit from the savings in time associated with the restoration of an existing piping system. An eleventh objective of the invention is to provide methods, systems and devices for repairing interior walls of pipes where customers benefit from the economical savings associated with the restoration of an existing piping system, since walls, ceilings floors, and/or grounds do not always need to be broken and/or cut through. A twelfth objective of the invention is to provide methods, systems and devices for repairing interior walls of pipes where income producing properties experience savings by remaining commercially usable, and any operational interference and interruption of income-producing activities is minimized. A thirteenth objective of the invention is to provide methods, systems and devices for repairing interior walls of pipes where health benefits had previously accrued, as the water to metal contact will be stopped by a barrier coating thereby preventing the leaching of metallic and potentially other harmful products from the pipe into the water supply such as but not limited to lead from solder joints and from lead pipes, and any excess leaching of copper, iron and lead. A fourteenth objective of the invention is to provide methods, systems and devices for repairing interior walls of pipes where the pipes are being restored in-place thus causing less demand for new metallic pipes, which is a non-renewable resource. A fifteenth objective of the invention is to provide methods, systems and devices for repairing interior walls of pipes using a less intrusive method of repair where there is less building waste and a reduced demand on expensive landfills. A sixteenth objective of the invention is to provide methods, systems and devices for repairing interior walls of pipes where the process uses specially filtered air that reduces possible impurities from entering the piping system during the process. A seventeenth objective of the invention is to provide methods, systems and devices for repairing interior walls of pipes where the equipment package is able to function safely, cleanly, and efficiently in high customer traffic areas. An eighteenth objective of the invention is to provide methods, systems and devices for repairing interior walls of pipes where the equipment components are mobile and maneuverable inside buildings and within the parameters typically found in single-family homes, multi unit residential buildings and various commercial buildings. A nineteenth objective of the invention is to provide methods, systems and devices for repairing interior walls of pipes where the equipment components can operate quietly, within the strictest of noise requirements such as approximately seventy four decibels and below when measured at a distance of approximately several feet away. A twentieth objective of the invention is to provide methods, systems and devices for repairing interior walls of pipe where the barrier coating material for application in a variety of piping environments, and operating parameters such as but not limited to a wide temperature range, at a wide variety of airflows and air pressures, and the like. A twenty first objective of the invention is to provide methods, systems and devices for repairing interior walls of pipes where the barrier coating material and the process is functionally able to deliver turnaround of restored piping systems to service within approximately twenty four hours or less or no more than approximately ninety six hours for large projects. A twenty second objective of the invention is to provide methods, systems and devices for repairing interior walls of pipes where the barrier coating material is designed to operate safely under NSF(National Sanitation Foundation) Standard 61 criteria in domestic water systems, with adhesion characteristics within piping systems in excess of approximately 400 PSI. A twenty third objective of the invention is to provide methods, systems and devices for repairing interior walls of pipes where the barrier coating material is designed as a long-term, long-lasting, durable solution to pipe corrosion, pipe erosion, pinhole leak and related water damage to piping systems where the barrier coating extends the life of the existing piping system. A twenty fourth objective of the invention is to provide methods, systems and devices for both cleaning and coating interiors of pipes having diameters of up to approximately 6 inches using dry particulates, such as sand and grit, prior to coating the interior pipe walls. A twenty fifth objective of the invention is to provide methods, systems and devices for both cleaning and coating interiors of pipes having diameters of up to approximately 6 inches in plural story buildings, without having to section off small sections of piping for cleaning and coating applications. A twenty sixth objective of the invention is to provide methods, systems and devices for cleaning the interiors of an entire piping system in a building in a single pass run operation. A twenty seventh objective of the invention is to provide methods, systems and devices for barrier coating the interiors of an entire piping system in a building in a single pass run operation. The novel method and system of pipe restoration prepares and protects small diameter piping systems such as those within the diameter range of approximately ⅜ of an inch to approximately six inches and can include straight and bent sections of piping from the effects of water corrosion, erosion and electrolysis, thus extending the life of small diameter piping systems. The barrier coating used as part of the novel process method and system, can be used in pipes servicing potable water systems, meets the criteria established by the National Sanitation Foundation (NSF) for products that come into contact with potable water. The epoxy material also meets the applicable physical criteria established by the American Water Works Association as a barrier coating. Application within buildings ranges from single-family homes to smaller walk-up style apartments to multi-floor concrete high-rise hotel/resort facilities and office towers, as well as high-rise apartment and condominium buildings and schools. The novel method process and system allows for barrier coating of potable water lines, natural gas lines, HVAC piping systems, hot water lines, cold water lines, drain lines, and fire sprinkler systems. The novel method of application of an epoxy barrier coating is applied to pipes right within the walls eliminating the traditional destructive nature associated with a re-piping job. Typically 1 riser system or section of pipe can be isolated at a time and the restoration of the riser system or section of pipe can be completed in less than one to four days (depending upon the building size and type of application) with water restored within approximately 24 to approximately 96 hours. For hotel and motel operators that means not having to take rooms off line for extended periods of time. Too, for most applications, there are no walls to cut, no large piles of waste, no dust and virtually no lost room revenue. Entire building piping systems can be cleaned within one run through pass of using the invention. Likewise, an entire building piping system can be coated within one single pass operation as well. Once applied, the epoxy coating creates a barrier coating on the interior of the pipe. The application process and the properties of the epoxy coating ensure the interior of the piping system is fully coated. Epoxy coatings are characterized by their durability, strength, adhesion and chemical resistance, making them an ideal product for their application as a barrier coating on the inside of small diameter piping systems. The novel barrier coating provides protection and extended life to an existing piping system that has been affected by erosion corrosion caused from internal burrs, improper soldering, excessive turns, and excessive water velocity in the piping system, electrolysis and “wear” on the pipe walls created by suspended solids. The epoxy barrier coating will create an approximately 4 mil or greater covering to the inside of the piping system. There are primarily 3 types of metallic piping systems that are commonly used in the plumbing industry—copper, steel and cast iron. New steel pipes are treated with various forms of barrier coatings to prevent or slow the effects of corrosion. The most common barrier coating used on steel pipe is the application of a zinc based barrier coat commonly called galvanizing. New copper pipe has no barrier coating protection and for years was thought to be corrosion resistant offering a lifetime trouble free use as a piping system. Under certain circumstances that involved a combination of factors of which the chemistry of water and installation practices a natural occurring barrier coating would form on the inside of copper pipes which would act as a barrier coating, protecting the copper piping system against the effects of corrosion from the water. In recent history, due to changes in the way drinking water is being treated and changes in installation practices, the natural occurring barrier coating on the inside of copper pipe is not being formed or if it was formed is now being washed away. In either case without an adequate natural occurring barrier coating, the copper pipe is exposed to the effects of corrosion/erosion, which can result in premature aging and failure of the piping system. With galvanized pipe the zinc coating wears away leaving the pipe exposed to the effects of the corrosive activity of the water. This results in the pipe rusting and eventually failing. The invention can also be used with piping systems having plastic pipes, PVC pipes, composite material, and the like. The novel method and system of corrosion control by the application of an epoxy barrier coating to new or existing piping systems is a preventative corrosion control method that can be applied to existing piping systems in-place. The invention includes novel methods and equipment for providing barrier coating corrosion control for the interior walls of small diameter piping systems. The novel process method and system of corrosion control includes at least three basic steps: Air Drying a piping system to be serviced; profiling the piping system using an abrasive cleaning agent; and applying the barrier coating to selected coating thickness layers inside the pipes. The novel invention can also include two additional preliminary steps of: diagnosing problems with the piping system to be serviced, and planning and setting up the barrier coating project onsite. Finally, the novel invention can include a final end step of evaluating the system after applying the barrier coating and re-assembling the piping system. Further objects and advantages of this invention will be apparent from the following detailed description of the presently preferred embodiments which are illustrated schematically in the accompanying drawings. BRIEF DESCRIPTION OF THE FIGURES FIG. 1 shows the general six steps that is an overview for applying the barrier coating. FIGS. 2A , 2 B, 2 C and 2 D shows a detailed process flowchart using the steps of FIG. 1 for providing the barrier coating. FIG. 3 shows a side view of a multi-story story building using the novel barrier coating corrosion control method and system of the invention. FIG. 4 shows a side view of the novel exhaust air diffuser used in the barrier coating control system in FIG. 3 . FIG. 5A shows a perspective view of the novel portable air distribution manifold used in the barrier coating control system in FIG. 3 . FIG. 5B shows a side view of the novel Pressure Generator System (Sander) 500 used in the barrier coating control system of FIG. 3 . FIG. 5C is an enlarged view of the front control panel for use with the pressure generator system 500 of FIG. 5B . FIG. 6A shows a side view of the novel Abrasive Reclaim Separator Module (Pre-Filter) used in the barrier coating control system of FIG. 3 . FIG. 6B shows an end view of the novel Abrasive Reclaim Separator Module (Pre-Filter) used in the barrier coating control system of FIG. 3 . FIG. 7A shows a side view of the novel Dust Collector System 700 (Filter) used in the barrier coating control system of FIG. 3 FIG. 7B shows an enlarged side cross-sectional view of the mounted Cartridge Filters used in the Dust Collector System of FIG. 7A . FIG. 8A shows a perspective view of the novel Portable Epoxy Metering and Dispensing Unit 800 (Epoxy Mixer) used in the barrier coating control system of FIG. 3 FIG. 8B shows another perspective view of the novel Portable Epoxy Metering and Dispensing Unit 800 (Epoxy Mixer) used in the barrier coating control system of FIG. 3 FIG. 8C shows an enlarged view of the foot dispenser activator a part of the novel Portable Epoxy Metering and Dispensing Unit 800 (Epoxy Mixer) used in the barrier coating control system of FIG. 3 FIG. 8D is an enlarged view of the mixing tubes and mixing head of FIG. 8B . FIG. 9 shows a side view of the novel Main Air Header and Distributor 200 (Header) used in the barrier coating control system of FIG. 3 DESCRIPTION OF THE PREFERRED EMBODIMENTS Before explaining the disclosed embodiments of the present invention in detail it is to be understood that the invention is not limited in its application to the details of the particular arrangements shown since the invention is capable of other embodiments. Also, the terminology used herein is for the purpose of description and not of limitation. FIG. 1 shows the general six steps for a project overview for applying the barrier coating to an existing piping system, which include step one, 10 program diagnosis, step two, 20 project planning, step three, 30 drying piping system, step four 40 , profiling the piping system, step five, 50 barrier coating interior walls of the pipes in the piping system, and final step six 60 evaluation and return to operation of the piping system. Step One—Problem Diagnosis 10 For step one, 10 , several steps can be done to diagnose the problem with a piping system in a building, and can include: (a) Interview onsite engineering staff, property mangers, owners or other property representatives as to the nature of the current problem with the piping system. (b) Evaluation of local and on-site water chemistry being used in the piping system for hardness and aggressive qualities. (c) Engineering evaluation, if necessary, to determine extent of present damage to the wall thickness of the piping and overall integrity of the piping system. (d) Additional on-site testing of piping system, if necessary, identifying leaks or the nature or extent of leaking. (e) Corrosion control proposal development for client, including options for pipe and fitting replacement where necessary. After completion of step one, 10 , the project planning and setup step 20 can be started. Step Two—Project Planning and Setup 20 For step two, 20 , several steps can be followed for planning and setup for restoring the integrity of the piping system in a building, and can include: (a) Complete contract development with client, after the diagnosis contract has started. (b) Commence project planning with site analysis crew, project management team, and on-site engineering/maintenance staff. (c) Plan delivery of the equipment and supplies to the worksite. (d) Complete equipment and supply delivery to worksite. (e) Commence and complete mechanical isolation of the piping system. (f) Commence and complete set up of hosing and equipment. Step Three—Air Drying—Step 1 Method of Corrosion Control 30 For step three, 30 , the piping system to be prepared for the coating by drying the existing pipes, and can include (a) Piping systems are mapped. (b) Isolations of riser systems or pipe sections are prepared and completed. (c) The isolated piping system to receive the barrier coating is adapted to be connected to the barrier coating equipment. (d) The isolated riser system is drained of water. (e) Using moisture and oil free, hot compressed air, a flushing sequence is completed on the riser system to assure water is removed. (f) Riser system is then dried with heated, moisture and oil free compressed air. (g) Length of drying sequence is determined by pipe type, diameter, length complexity, location and degree of corrosion contained within the piping system, if any. (h) Inspections are completed to assure a dry piping system ready for the barrier coating. Step Four—Piping System Profiling—Step 2 of Method of Corrosion Control 40 For step four, 40 , the piping system is to be profiled, and can include: (a) Dried pipes can be profiled using an abrasive agent in varying quantities and types. The abrasive medium can be introduced into the piping system by the use of the moisture and oil free heated compressed air using varying quantities of air and varying air pressures. The amount of the abrading agent is controlled by the use of a pressure generator. (b) The abraded pipe, when viewed without magnification, must be generally free of all visible oil, grease, dirt, mill scale, and rust. Generally, evenly dispersed, very light shadows, streaks, and discolorations caused by stains of mill scale, rust and old coatings may remain on no more than approximately 33 percent of the surface. Also, slight residues of rust and old coatings may be left in the craters of pits if the original surface is pitted. (c) Pipe profiling is completed to ready the pipe for the application of the barrier coating material. (d) Visual inspections can be made at connection points and other random access areas of the piping system to assure proper cleaning and profiling standards are achieved. (e) An air flushing sequence is completed to the riser system to remove any residuals left in the piping system from the profiling stage. Step Five—Corrosion Control Epoxy Sealing and Protection of the Piping—Step 3 of the Method of Corrosion Control 50 For step five, 50 , the piping system is to barrier coated and can include: (a) Piping system can be heated with hot, pre-filtered, moisture and oil free compressed air to an appropriate standard for an epoxy coating application. (b) Piping system can be checked for leaks. (c) Corrosion control barrier coating material can be prepared and metered to manufacturer's specifications using a proportionator. (d) Corrosion control barrier coating material can be injected into the piping system using hot, pre-filtered, moisture and oil free compressed air at temperatures, air volume and pressure levels to distribute the epoxy barrier coating throughout the pipe segment, in sufficient amounts to eliminate the water to pipe contact in order to create an epoxy barrier coating on the inside of the pipe. (e) The epoxy barrier coating can be applied to achieve coating of approximately 4 mils and greater. (f) Once the epoxy barrier coating is injected warm, pre-filtered, moisture and oil free compressed air can be applied over the internal surface of the pipe to achieve the initial set of the epoxy barrier coating. (g) Confirm that all valves and pipe segments support appropriate air flow indicating clear passage of the air through the pipe i.e.: no areas of blockage. Allow the barrier coating to cure to manufacturer's standards. Step Six—System Evaluation and Re-Assembly 60 The final step six, 60 allows for restoring the piping system to operation and can include: (a) Remove all process application fittings. (b) Examine pipe segments to assure appropriate coating standards. (c) Re-confirm that all valves and pipe segments support appropriate air flow. (d) Install original valves, fittings/fixtures, or any other fittings/fixtures as specified by building owner representative. (e) Reconnect water system, and water supply. (f) Complete system checks, testing and evaluation of the integrity of the piping system. (g) Complete a water flush of system, according to manufacturer's specifications. (h) Evaluate water flow and quality. (i) Document riser schedule, and complete pipe labeling. FIGS. 2A , 2 B, 2 C and 2 D show a detailed process flowchart using the steps of FIG. 1 for providing the barrier coating. These flow chart figures show a preferred method of applying a novel barrier coating corrosion control for the interior of small diameter piping systems following a specific breakdown of a preferred application of the invention. FIG. 3 shows a side view of a ten story building setup for using the novel method and system of the invention. Components in FIG. 3 will now be identified as follows: IDENTIFIER EQUIPMENT 100 395, 850, 1100, 1600 CFM Compressors Outfitted with Aftercooler, Water separator, Fine Filter and Reheater 200 Main Air Header and Distributor (Main Header) 300 Exhaust Air Diffuser (Muffler) 400 Portable Air Distribution Manifold (Floor Header) 500 Pressure Generator System (Sander) 600 Reclaim Separator Module (Pre-Filter) 700 Dust Collector System (Filter) 800 Portable Epoxy Metering and Dispensing Unit (Epoxy Mixer) 900 Epoxy Barrier Coating Referring to FIG. 3 , components 100 - 800 can be located and used at different locations in a ten story building. The invention allows for an entire building piping system to be cleaned in one single pass through run without having to dismantle either the entire or multiple sections of the piping system. The piping system can include pipes having diameters of approximately ⅜ of an inch up to approximately 6 inches in diameter with the piping including bends up to approximately ninety degrees or more throughout the building. The invention allows for an entire building piping system to have the interior surfaces of the pipes coated in one single pass through run without having to dismantle either the entire or multiple parts of the piping system. Each of the components will now be defined. 100 Air Compressor The air compressors 100 can provide filtered and heated compressed air. The filtered and heated compressed air employed in various quantities is used, to dry the interior of the piping system, as the propellant to drive the abrasive material used in cleaning of the piping system and is used as the propellant in the application of the epoxy barrier coating and the drying of the epoxy barrier coating once it has been applied. The compressors 100 also provide compressed air used to propel ancillary air driven equipment. 200 Main Air Header and Distributor An off the shelf main header and distributor 200 shown in FIGS. 3 and 9 can be one Manufactured By: Media Blast & Abrasives, Inc. 591 W. Apollo Street Brea, Calif. 92821 The components of the main header and distributor of FIG. 9 are labeled as follows. Description of Main Header Equipment Describing Each Component: 12 & 14 Gauge Steel Construction Approximate Dimensions: 28″w×27″l×53″h Ford Grabber Blue Powder-coating Air Pressure Gauge 205 Regulator Adjustment 210 Air Pressure Regulator 215 Moisture Bleeder Valve 220 2 2″ NPT Inlet With Full Port Ball Valve 225 14-1″ Side-Mounted Ball Valves—Regulated Air 230 4-1″ Top Mounted Ball Valves—Unregulated Air 235 1-2″ Top Mounted full port Ball Valve—Unregulated Air 240 1-2″ Top Mounted Full Port Ball Valve—Regulated Air 245 1.9 Cubic Feet Pressure Pot 250 Insulated Cabinet 255 Two Inflatable Tires 260 Push/Pull Handles 265 Referring to FIGS. 3 and 9 , the Main Header 200 provides safe air management capability from the air compressor for both regulated and unregulated air distribution (or any combination thereof) to the various other equipment components and to both the piping system risers and fixture outlets for a range of piping configurations from a single family home to a multi-story building. The air enters through the 2″ NPT inlet, 225 to service the pressure vessel. The main header 200 can manage air capacities ranging to approximately 1100 CFM and approximately 125 psi. There are many novel parts and benefits with the Main Header and Distributor 200 . The distributor is portable and is easy to move and maneuver in tight working environments. Regulator Adjustment 210 can easily and quickly manage air capacities ranging to approximately 1600 CFM and approximately 200 psi, and vary the operating airflows to each of the other ancillary equipment associated with the invention. The Air Pressure Regulator 210 and the Method of Distributing the air allows both regulated and unregulated air management from the same equipment in a user-friendly, functional manner. The approximately 1″ Valving 230 , 235 , 245 allows accommodation for both approximately 1″ hosing and with adapters, and hose sizes of less than approximately 1″ can be used to meet a wide variety of air demand needs on a job site. The insulated cabinet 255 , surrounding air works dampens noise associated with the movement of the compressed air. The insulated cabinet 255 , helps retain heat of the pre-dried and heated compressed air, the pre-dried and heated compressed air being an integral part of the invention. The insulated cabinet 255 , helps reduce moisture in the pressure vessel and air supply passing through it. Finally, the valving of the pressure vessel allows for delivery (separate or simultaneous) of regulated air to the side mounted air outlet valves 230 , the top-mounted regulated air outlet valves 245 , as well as the top mounted unregulated air outlet valves 235 and 240 . FIG. 4 shows a side view of the novel exhaust air diffuser 300 used in the barrier coating control system in FIG. 3 . 300 Exhaust Air Diffuser (Muffler) Referring to FIGS. 3 and 4 , an exhaust air diffuser and muffler 300 that can be used with the invention can be one Manufactured By: Media Blast & Abrasives, Inc. 591 W. Apollo Street, Brea, Calif. 92821. Description of Muffler 300 components: 12 & 14 Gauge Steel Construction Approximate Dimensions: 34″w×46″1×76″h Ford Grabber Blue Powder-coating Vented Access Panels on Both Sides of Unit 305 Vented End Panels 310 Dust Drawer with Removable Pan 315 Canvas Dust Bag Diffusers 320 2″ NPT Inlet 325 4″×8″ Expansion Chamber 330 Overhead Plenum 335 Two Swivel Casters 340 Two Locking Casters 350 Push/Pull Handles 360 Referring to FIGS. 3 and 4 , the Air Diffuser/Muffler 300 allows the safe, wholesale dumping of unregulated or regulated air from the compressor off of the Main Header 200 through the approximately 2″ NPT inlet, into the expansion chamber and canvas dust bag diffusers for the purpose of controlling the air temperature in the piping system during the drying phase, the pipe warming phase, the epoxy application phase and the initial curing phase of the epoxy barrier coating material after it is injected into the piping system. The Air diffuser 300 can eliminate the need to operate the air filter 600 during various stages of the process, promoting energy efficiency as the filter 600 is an air assisted and electrically powered piece of invention. There are many novel parts and benefits to the Exhaust air diffuser 300 . The diffuser's portability allows for easy to move and maneuver in tight working environments. Vented access panels 305 allow for safe and even distribution of the air upon venting, prevents the build up of backpressure of the venting air and reduces the noise of the venting air. A Dust Drawer with Removable Pan 315 allows for easy clean out of the expansion chamber. A Canvas Dust Bag Diffuser 320 assures quiet, customer friendly discharge of air. An approximately 2″ NPT Inlet 325 allows full range of air diffusion from approximately 1″ to approximately 2″ discharge hoses. A 4″×8″ Expansion Chamber 330 allows for rapid dispersing of the air upon entering the Air Diffuser 300 . The expansion chamber 330 permits the compressed air that enters the diffuser 300 to expand allowing for a more efficient and safe passage to exit, which reduces the noise of the air upon departure and helps reduce the build up of backpressure of the exiting air from the piping system. The Air Diffuser 300 promotes the rapid unrestricted movement of the compressed air in volumes greater than approximately 1100 CFM and can operate with air pressures greater than approximately 120 PSI. When used in conjunction with the heated, pre-filtered compressed air of the compressor 100 , the use of the Air Diffuser 300 creates a more efficient movement of the heated air, which results in a cost savings by drying the pipes faster, drying the epoxy faster, which in turn saves manpower, fuel and reduces the operational time of the compressor 100 . FIG. 5A shows a preferred portable air distribution manifold 400 that can be used in the exemplary setup shown in FIG. 3 400 Portable Air Distribution Manifold Referring to FIGS. 3 and 5A , an on off-the-shelf manifold 400 can be one Manufactured By: M & H Machinery 45790 Airport Road, Chilliwack, BC, Canada Description of Manifold 400 Components: Main Air Cylinder 2½″×12″ Schedule 40 Steel Construction Ford Grabber Blue Paint Finishes 4-1″ Welded Nipples Placed at a 45° Angle to the Base Cylinder; Male Threaded 410 1″ NPT Female Threaded Portals at Each End of Cylinder 420 2 Metal Legs for Support and Elevation of Manifold 430 Pressure Rated Vessels to 125 PSI or Greater 440 Attached for Air Control, 1″ Full Port Ball Valves NPT; Female Threaded 450 All Hose End Receptors are NPT 1″; Female Threaded 460 As part of the general air distribution system set up, the floor manifolds 400 can be pressure rated vessels designed to evenly and quietly distribute the compressed air to at least 5 other points of connection, typically being the connections to the piping system. Airflow from each connection at the manifold is controlled by the use of individual full port ball valves. There are many novel parts and benefits to the Air Manifold 400 . The portability of manifold 400 allows for easy to move and maneuver in tight working environments. The elevated legs 430 provide a stable base for unit 400 as well as keep the hose end connections off the floor with sufficient clearance to permit the operator ease of access when having to make the hose end connections. The threaded nipples 410 placed at approximately 45° angle allow for a more efficient use of space and less restriction and constriction of the airline hoses they are attached to. Multiple manifolds 400 can be attached to accommodate more than 5 outlets. The manifolds can be modular and can be used as 1 unit or can be attached to other units and used as more than 1. FIG. 5B shows a perspective view of the novel pressure generator sander system 500 used in the barrier coating control system in FIG. 3 . FIG. 5C shows the front control panel of the sander system. 500 Pressure Generator System-Sander Referring to FIGS. 3 , 5 B and 5 C, a pressure generator sander 500 that can be used with the invention can be one Manufactured By: Media Blast & Abrasives, Inc. 591 W. Apollo Street Brea, Calif. 92821. Description of Sander 500 Components: 12 & 14 Gauge Steel Construction Approximate Dimensions: 20″ w×24″ 1×42″ h Ford Grabber Blue Powder-coating 1—1″ NPT Inlets 505 1—1″ NPT Outlet 510 3—Air Breather Mufflers 515 Pop-up Valve gasket 520 Pop-up Valve 525 Hand Port Gasket 530 Pressure Pot with Hand Port and Hopper 535 Filler Lid with Latches 540 Mixing Valve 545 Remote Regulator 550 Process Valve 555 Toggle Switch 560 Air Pressure Gauge 565 Regulator Adjustment 570 Pulse Button 580 Wheel Assembly 585 2—Inflatable Tires 590 The pressure generating sander system 500 can provide easy loading and controlled dispensing of a wide variety of abrasive medium in amounts up to approximately 1.3 US gallons at a time. The pressure generator sander can include operational controls that allow the operator to easily control the amount of air pressure and control the quantity of the abrasive medium to be dispersed in a single or multiple application. The abrasive medium can be controlled in quantity and type and is introduced into a moving air steam that is connected to a pipe or piping systems that are to be sand blasted clean by the abrasive medium. The sand can be introduced by the pressure generator sander system 500 by being connected to and be located outside of the piping system depicted in FIG. 3 . The novel application of the sander system 500 allows for cleaning small pipes having diameters of approximately ⅜″ up to approximately 6″. Table 1 shows a list of preferred dry particulate materials with their hardness ratings and grain shapes that can be used with the sand generator 500 , and Table 2 shows a list of preferred dry particulate particle sieve sizes that can be used with the invention. TABLE 1 PARTICULATES Material Hardness Rating Grain Shape Diamond 10 Cubical Aluminium Oxide 9 Cubical Silica 5 Rounded Garnet 5 Rounded Walnut shells 3 Cubical TABLE 2 PARTICULATE SIZE SIEVE SIZE OPENING U.S. Mesh Inches Microns Millimeters 4 .187 4760 4.76 8 .0937 2380 2.38 16 .0469 1190 1.19 25 .0280 710 .71 45 .0138 350 .35 There are many novel parts and benefits to the use of the Pressure Generator Sander System 500 . The portability allows for easy to move and maneuver in tight working environments. The sander 500 is able to accept a wide variety of abrasive media in a wide variety of media size. Variable air pressure controls 570 in the sander 500 allows for management of air pressures up to approximately 125 PSI. A mixing Valve 545 adjustment allows for setting, controlling and dispensing a wide variety of abrasive media in limited and controlled quantities, allowing the operator precise control over the amount of abrasive medium that can be introduced into the air stream in a single or multiple application. The filler lid 540 , incorporated as part of the cabinet and the pressure pot allows the operator to load with ease, controlled amounts of the abrasive medium into the pressure pot 535 . The pulse button 580 can be utilized to deliver a equipment 700 , which filters, from the exhausting air, fine particulates, that may not have been captured with the Pre-Filter 600 . There are many novel parts and benefits to the Pre-Filter 600 . The pre-filter has portability and is easy to move and maneuver in tight working environments. The Dust Drawer with Removable Pan 610 allows for easy clean out of the abrasive media and debris from the pipe. The Cyclone Chamber/Separator 630 slows and traps the abrasive media and debris from the piping system and air stream, and prevents excess debris from entering into the filtration equipment. The 2—approximately 2″ NPT Inlet 620 allows a full range of air filtration from two separate riser or piping systems. Use of the approximately 8″ or greater flex tube 640 as an expansion chamber results in reducing the air pressure of the air as it leaves the pre-filter 600 and reduces the potential for back pressure of the air as it departs the pre-filter and enhances the operational performance of the air filter. When used in conjunction with the air filter 700 , the Pre-filter 600 provides a novel way of separating large debris from entering the final stage of the filtration process. By filtering out the large debris with the pre-filter 600 this promotes a great efficiency of filtration of fine particles in the final stages of filtration in the air filter 700 . The approximately 8″ air and dust outlet 640 to the air filter 700 from the pre-filter 600 permits the compressed air to expand, slowing it in velocity before it enters the air filter 700 , which enhances the operation of the air filter 700 . Process cost savings are gained by the use of the pre-filter 600 by reducing the impact of filtering out the large amounts of debris at the pre-filter stage prior to air entering the air filter 700 . This provides for greater operating efficiencies at the air filter 700 a reduction in energy usage and longer life and use of the actual fine air filters 760 used in the air filter 700 . single sized quantity of the abrasive material into the air stream or can be operated to deliver a constant stream of abrasive material in to the air stream. All operator controls and hose connections can be centralized for ease of operator use. FIG. 6A shows a side view of the novel Abrasive Reclaim Separator Module (Pre-Filter) 600 used in the barrier coating control system of FIG. 3 . FIG. 6B shows an end view of the novel Abrasive Reclaim Separator Module (Pre-Filter) 600 used in the barrier coating control system of FIG. 3 . 600 Abrasive Reclain Separator Module (Pre-Filter) Referring to FIGS. 3 , 6 A and 6 B, an off-the-shelf pre-filter that can be used with the invention can be one Manufactured By: Media Blast & Abrasives, Inc. 591 W. Apollo Street Brea, Calif. 92821 Description of Pre-Filter 600 Components: 12 & 14 Gauge Steel Construction Approximate Dimensions: 23″w×22″1×36″h Ford Grabber Blue Powder-coating Dust Drawer with Removable Pan 610 2—2″ NPT Inlets 620 Approximate Dimensions: 13¼″w×13¼″1×17″h Cyclone Chamber/Separator 630 8″ Air and Dust Outlet with Flexible Duct to Air Filter 640 Two Inflatable Tires 650 Push/Pull Handle 660 During the pipe profiling stage, the Pre-Filter 600 allows the filtering of air and debris from the piping system for more than two systems at a time through the 2-approximately 2″ NPT inlets 620 . The cyclone chamber/separator 630 captures the abrasive material and large debris from the piping system, the by products of the pipe profiling process. The fine dust particles and air escape through the approximately 8″ air and dust outlet 640 at the top of the machine and are carried to the dust collection 700 Dust Collection Filter Referring to FIGS. 3 , 7 A and 7 B, an off-the-shelf example if a filter 700 used with the invention can be one Manufactured By: Media Blast & Abrasives, Inc. 591 W. Apollo Street, Brea, Calif. 92821. Description of Air Filter 700 Components: 12 & 14 Gauge Steel Construction Approximate Dimensions: 24″ w×32″ 1×65″ h Ford Grabber Blue Powder-coating Dust Drawer with Removable Pan and Tightening Knobs 705 1—¾ NPI Inlet 710 2.0 HP Baldor Motor, Volts 115/230 715 8″ Air and Dust Inlet with Flexible Duct to Pre-Filter 720 Ball Vibrator Muffler 725 2—Locking Wheels 730 2—Swivel and Locking Wheels 735 Pushbutton Switch 740 Mushroom Head Switch 745 Selector Switch 750 Tightening Knob 755 2—Corrugated Cartridge Filters, approximately 99.98% Efficient, Collecting 0.5 Micron Particles (based on SAE-J726 test) 760 Cartridge Mounting Rods 765 Cartridge Mounting Plates 770 Filter Tightening Knobs 775 Filter Ball Tightening Knobs 780 Sliding Air Control Exit Vent 785 During the pipe profiling stage, the filter or dust collector 700 is the final stage of the air filtration process. The dust collector 700 filters the passing air of fine dust and debris from the piping system after the contaminated air first passes through the pre-filter 600 (abrasive reclaim separator module). During the epoxy coating drying stage the filter 700 is used to draw air through the piping system, keeping a flow of air running over the epoxy and enhancing its drying characteristics. The filter 700 creates a vacuum in the piping system which is used as method of checking for airflow in the piping system, part of the ACE DuraFlo process. The dust collector 700 can be capable of filtering air in volumes up to approximately 1100 CFM. There are many novel parts and benefits to the Air Filter 700 . The air filter has portability and is easy to move and maneuver in tight working environments. The Dust Drawer with Removable Pan 705 allows for easy clean out of the abrasive media and debris from the filtration chamber. The 8″ flexible duct 640 (from FIG. 6A permits the compressed air to expand and slow in velocity prior to entering the dust collector 700 , enhancing efficiency. The sliding air control exit vent 785 permits use of a lower amperage motor on start up. The reduced electrical draw enables the dust collector 700 to be used on common household electrical currents while still being able to maintain its capacity to filter up to approximately 1100 CFM of air. The air filter 700 keeps a flow of air running over the epoxy and enhancing its drying and curing characteristics. The dust collector 700 creates a vacuum in the piping system, which is used as method of checking for airflow in the piping system. 800 Portable Epoxy Metering and Dispensing Unit Referring to FIGS. 3 , 8 A, 8 B and 8 C, a metering and dispensing unit 800 used with the invention can be one Manufactured by: Lily Corporation, 240 South Broadway, Aurora, Ill. 60505-4205. Description of Metering and Dispensing Unit 800 Components: Aluminum Frame And Cabinet Construction Approximate Dimensions: 48″ L×48″ H×22″ W Blue and Black Anodized Finishes Electrical Powered Space Heating Element and Thermostat 805 Temperature Gauge 810 1—3 Gallon Stainless Steel Pressure Pot for Resin Part A 815 1—3 Gallon Stainless Steel Pressure Pot for Catalyst Part B 820 Pressure Valve For Each Tank 825 Side Door Access Panel 830 Parts and Tool Drawer 835 Aluminum Removable Cover To Access Pressure Pots 840 Adjustable Cycle or Shot Counter 845 4 Wheels—Swivel and Locking 850 Coalescing Air Filter 855 Air Pressure Regulator and Gauge 860 Foot Dispenser Activator 865 Abort Switch 870 On/Off Control Switch 875 Compressed Air Driven Epoxy Meter and Pump Adjustable for Dispensing Up To 14.76 Oz of Mixed Epoxy Per Single Application. Multiple Applications Can Dispense Up To 75 Gallons of Epoxy Per Hour. 880 Threaded Epoxy Mixing Head To Accommodate Disposable Epoxy Mixing Tubes 887 , and mixing head 885 Push/Pull Handle 890 Epoxy Carrying Tube Hanger 895 The Portable Epoxy Metering and Dispensing Unit 800 can store up to approximately 3 US gallons of each of A and B component of the two mix component epoxy, and can dispense single shots up to approximately 14.76 oz, in capacities up to approximately 75 US gallons per hour. The unit 800 can be very mobile and can be used both indoors and outdoors, and it can operate using a 15 Amp 110 AC electrical service i.e.: regular household current and approximately 9 cubic feet (CFM) at 90 to 130 pounds per square inch. The unit 800 requires only a single operator. The epoxy used with the unit 800 can be heated using this unit to its recommended temperature for application. The epoxy can be metered to control the amount of epoxy being dispensed. There are many novel parts and benefits to the Epoxy Metering and Dispensing Unit 800 , which include portability and is easy to move and maneuver in tight working environments. The heated and insulted cabinet, all epoxy transit hoses, valves and pumps can be heated within the cabinet. The Top filling pressurized tanks 815 and 820 offers ease and access for refilling. Epoxy can be metered and dispensed accurately in single shot or multiple shots having the dispensing capacity up to approximately 14.76 ounces of material per shot, up to approximately 75 gallons per hour. The position of mixing head 885 , permits a single operator to fill the portable epoxy carrying tubes 887 in a single fast application. The drip tray permits any epoxy overspill at the time of filling to be contained in the drip tray, containing the spill and reducing cleanup. The epoxy carrying tube hanger 895 allows the operator to fill and temporarily store filled epoxy tubes, ready for easy distribution. The pump 880 and heater 805 combination allows for the epoxy to metered “on ratio” under a variety of conditions such as changes in the viscosity of the epoxy components which can differ due to temperature changes which effect the flow rates of the epoxy which can differ giving the operator an additional control on placement of the epoxy by changing temperature and flow rates. Unit 800 overall provides greater operator control of the characteristics of the epoxy in the process. 900 Epoxy Barrier Coating Referring to FIGS. 3 and 8A , 8 B and 8 C, a preferred epoxy barrier coating that can be used with the invention can be one Manufactured by: CJH, Inc. 2211 Navy Drive, Stockton, Calif. 95206. The barrier coating product used in this process can be a 2-part thermo set resin with a base resin and a base-curing agent. The preferred thermo set resin is mixed as a two-part epoxy that is used in the invention. When mixed and applied, it forms a durable barrier coating on pipe interior surfaces and other substrates. The barrier coating provides a barrier coating that protects those coated surfaces from the effects caused by the corrosive activities associated with the chemistry of water and other reactive materials on the metal and other substrates. The epoxy barrier coating can be applied to create a protective barrier coating to pipes ranging in size approximately ⅜″ to approximately 6″ and greater. The barrier coating can be applied around bends intersections, elbows, t's, to pipes having different diameters and make up. The barrier coating can be applied to pipes in any position e.g.: vertical or horizontal, and can be applied as a protective coating to metal pipes used in fire sprinkler systems and natural gas systems. Up to approximately 4 mils thick coating layers can be formed on the interior walls of the pipes. The barrier coating protects the existing interior walls and can also stop leaks in existing pipes which have small openings and cracks, and the like, of up to approximately ⅜ th ″ in diameters in size. Although the process of application described in this invention includes application of thermo set resins other types of thermo set resins can be used. For example, other thermo set resins can be applied in the process, and can vary depending upon viscosity, conditions for application including temperature, diameter of pipe, length of pipe, type of material pipe comprised of, application conditions, potable and non potable water carrying pipes, and based on other conditions and parameters of the piping system being cleaned and coated by the invention. Other thermo set type resins that can be used include but are not limited to and can be one of many that can be obtained by numerous suppliers such as but not including: Dow Chemical, Huntsmans Advances Material, formerly Ciba Giegy and Resolution Polymers, formerly Shell Chemical. Although the novel invention can be applied to all types of metal pipes such as but not limited to copper pipes, steel pipes, galvanized pipes, and cast iron pipes, the invention can be applied to pipes made of other materials such as but not limited to plastics, PVC(polyvinyl chloride), composite materials, polybutidylene, and the like. Additionally, small cracks and holes in plastic type and metal pipes can also be fixed in place by the barrier coating. Although the preferred applications for the invention are described with building piping systems, the invention can have other applications such as but not limited to include piping systems for swimming pools, underground pipes, in-slab piping systems, piping under driveways, various liquid transmission lines, tubes contained in heating and cooling units, tubing in radiators, radiant in floor heaters, chillers and heat exchange units, and the like. While the invention has been described, disclosed, illustrated and shown in various terms of certain embodiments or modifications which it has presumed in practice, the scope of the invention is not intended to be, nor should it be deemed to be, limited thereby and such other modifications or embodiments as may be suggested by the teachings herein are particularly reserved especially as they fall within the breadth and scope of the claims here appended.

Methods and systems for providing cleaning and providing barrier coatings to interior wall surfaces of small diameter metal and composite piping systems in buildings. An entire piping system can be cleaned in one single pass by dry particulates forced by air throughout the building piping system by an external generator, and the entire piping system can be coated in one single pass by a machine also connected exterior to the piping system. Small diameter pipes can be protected by the effects of water corrosion, erosion and electrolysis, extending the life of small diameter piping systems such as copper, steel, lead, brass, cast iron piping and piping systems made of composite materials. The invention meets the National Sanitation Foundation standard for products and services that come into contact with potable water, and the American Water Works Association. Coatings can be applied to pipes having diameters of approximately ⅜″ up to approximately 6″ so that entire piping systems such as potable water lines, natural gas lines, HVAC piping systems, drain lines, and fire sprinkler systems in buildings such as single-family homes to smaller walk-up style apartments to multi-floor concrete high-rise hotel/resort facilities and office towers, as well as high-rise apartment and condominium buildings and schools, can be cleaned and coated to pipes within existing walls. The barrier coating forms an approximately 4 mils or greater covering to the inside of pipes. Entire buildings can return to service within approximately 24 to approximately 96 hours depending on the size of the building piping system.

CROSS REFERENCE TO RELATED APPLICATION This application claims priority from Japanese Patent Application No. 2010-171999 filed Jul. 30, 2010. The entire content of the priority application is incorporated herein by reference. TECHNICAL FIELD The present invention relates to an image forming device such as a color printer. BACKGROUND In well-known tandem image forming devices, photosensitive drums for colors of yellow, magenta, cyan and black are juxtaposed, and a toner image of each color is formed on the corresponding photosensitive drum substantially at the same time with one another. In case of a direct transferring system, each toner image formed on each photosensitive drum is sequentially superimposed onto a sheet passing beneath each photosensitive drum due to a circular movement of a conveyor belt. In case of an intermediate transferring system, each toner image is sequentially superimposed on an intermediate transfer belt to form a colored toner image, and the colored toner image is then transferred onto a sheet. Some of the toner carried on each photosensitive drum may sometimes remain deposited thereon without being transferred onto the sheet or the intermediate transfer belt. To this effect, some tandem image forming devices are provided with a drum cleaner for collecting remaining toner from each photosensitive drum. A belt cleaner has also been proposed for collecting toner remained on the conveyor belt or the intermediate transfer belt. Such belt cleaner includes a waste toner box in which the toner collected by the belt cleaner (waste toner) is stored. When both of the drum cleaner and the belt cleaner are provided, the toner collected by the drum cleaner is ejected onto a belt, and the toner on the belt is then collected by the belt cleaner. SUMMARY However, conventionally, the photosensitive drums are disposed upward of the belt, while the belt cleaner is disposed below the belt. This configuration inevitably requires a large dimension in height, resulting in a large image forming device. Furthermore, when the waste toner box becomes full, the belt needs to be removed first in order to take out the waste toner box from the image forming device. In view of the foregoing, it is an object of the present invention to provide a compact image forming device capable of facilitating disposal of waste toner. In order to achieve the above and other objects, the present invention provides an image forming device including a plurality of photosensitive drums, a plurality of developer cartridges, an endless belt, a plurality of first collecting units, a plurality of first conveying units, a second collecting unit, a second conveying unit, and a plurality of communication portions. The plurality of photosensitive drums is juxtaposedly arrayed in a first direction to form a drum array including a leading photosensitive drum and a trailing photosensitive drum in the first direction, each photosensitive drum extending in a second direction perpendicular to the first direction. Each of the plurality of developer cartridges is detachably mountable on each of the plurality of photosensitive drums, each developer cartridge having a developer accommodating chamber in which developer to be supplied to each photosensitive drum is stored and a waste developer accommodating chamber in which waste developer to be disposed is stored. The endless belt extends in the first direction and in the second direction and facing each of the plurality of photosensitive drums. Each of the plurality of first collecting units is disposed for each of the plurality of photosensitive drums, each first collecting unit collecting the waste developer on the corresponding photosensitive drum. Each of the plurality of first conveying units is disposed for each of the first collecting units and conveys the waste developer collected by the each first collecting unit toward the waste developer accommodating chamber of the corresponding developer cartridge. The second collecting unit is disposed adjacent to the leading photosensitive drum and collects the waste developer on the endless belt. The second conveying unit conveys the waste developer collected by the second collecting unit toward the waste developer accommodating chamber of the developer cartridge corresponding to the leading photosensitive drum. Each of the plurality of communication portions allows fluid communication between the first conveying unit and the waste developer accommodating chamber, wherein among the plurality of communication portions a specific communication portion in association with the leading photosensitive drum also allows fluid communication between the second conveying unit and the waste developer accommodating chamber. BRIEF DESCRIPTION OF THE DRAWINGS In the drawings: FIG. 1 is a cross-sectional view of a color printer according to an embodiment of the present invention, wherein a drawer frame is accommodated in the color printer, the drawer frame including drum units and toner cartridges; FIG. 2 is a cross-sectional view of the color printer of FIG. 1 , wherein the drawer frame according to the embodiment is in a pull-out state where the drawer frame is being pulled out; FIG. 3 is a cross-sectional view of the color printer of FIG. 1 , wherein one of the drum units is removed from the drawer frame in the pull-out state; FIG. 4 is a cross-sectional view of the color printer of FIG. 1 , wherein one of the toner cartridges is removed from the drawer frame in the pull-out state; FIG. 5 is an elevation view (front side view) of the drum unit and the toner cartridge shown in FIG. 1 , the drum unit including a communication unit; FIG. 6 is an elevation view (front side view) of the drum unit shown in FIG. 1 ; FIG. 7 is a cross-sectional view of the drum unit and the toner cartridge shown in FIG. 1 , wherein a toner accommodation chamber of the toner cartridge and a developing chamber of the drum unit are in fluid communication with each other; FIG. 8 is a cross-sectional view of the drum unit and the toner cartridge shown in FIG. 1 , wherein the toner accommodation chamber of the toner cartridge and the developing chamber of the drum unit are prevented from communicating with each other; FIG. 9 is a cross-sectional view of the drum unit taken along a line A-A shown in FIG. 7 ; FIG. 10 is a cross-sectional view of the drum unit taken along a line B-B shown in FIG. 7 ; FIG. 11 is a left side view of the drum unit shown in FIG. 1 ; FIG. 12 is a cross-sectional view of the drum unit shown in FIG. 11 ; FIG. 13 is a cross-sectional view of the toner cartridge and the communication unit shown in FIG. 5 , wherein the communication unit is not connected to the toner cartridge; and FIG. 14 is a cross-sectional view of the toner cartridge and the communication unit shown in FIG. 5 , wherein the communication unit is connected to the toner cartridge. DETAILED DESCRIPTION First, a general configuration of a tandem color printer 1 according to an embodiment of the present invention will be described with reference to FIGS. 1 through 4 . In the color printer 1 , a drawer frame 3 according to the embodiment is mountable. In the following description, a right side in FIG. 1 will be referred to as a front side, while a left side in FIG. 1 will be referred to as a rear side. The terms “upward”, “downward”, “upper”, “lower”, “above”, “below”, “beneath”, “right”, “left”, “front”, “rear” and the like will be used assuming that the color printer 1 is viewed from its front side. Also, directions with respect to the drawer frame 3 will be referenced based on an assumption that the drawer frame 3 is accommodated within the color printer 1 . As shown in FIG. 1 , the color printer 1 includes a main casing 2 within which the drawer frame 3 can be accommodated. The drawer frame 3 has a square frame shape in a plan view. A front cover 4 is pivotably movably provided at the front side of the main casing 2 . When the front cover 4 is opened, the drawer frame 3 is movable relative to the main casing 2 with respect to a horizontal direction. More specifically, the drawer frame 3 is movable between an accommodated position in which the drawer frame 3 is accommodated within the main casing 2 (shown in FIG. 1 ), and a pull-out position in which the drawer frame 3 is pulled out from the main casing 2 (shown in FIG. 2 ). In the drawer frame 3 , four drum units 5 are supported. The four drum units 5 are provided respectively for four colors of black, yellow, magenta and cyan to be used in the color printer 1 . The drum units 5 are juxtaposed in a front-to-rear direction according to the order of colors given above such that the drum unit 5 for black is positioned rearmost in the front-to-rear direction. Each drum unit 5 is detachably mountable on the drawer frame 3 from above when the drawer frame 3 is in the pull-out position, as shown in FIG. 3 . More specifically, as shown in FIG. 3 , the drawer frame 3 includes a left side frame (not shown) and a right side frame 302 disposed in opposition to each other in a left-to-right direction. On inner surfaces of the left side frame and the right side frame 302 (on a right side surface of the left side frame and a left side surface of the right side frame 302 ), four guide grooves 7 are formed respectively in correspondence with the four drum units 5 . Each guide groove 7 extends diagonally downward and frontward in the front-to-rear direction. A shaft 801 of a photosensitive drum 8 (described later) is inserted into the corresponding pair of guide grooves 7 from upward thereof, such that each drum unit 5 is being mounted in the drawer frame 3 along the guide grooves 7 , while the shaft 801 is slidingly moved downward within the guide grooves 7 . Likewise, when the drum unit 5 is removed from the drawer frame 3 , the drum unit 5 is pulled upward along the corresponding guide grooves 7 . Each drum unit 5 includes the photosensitive drum 8 , a charging roller 9 , a developing device 10 and a drum cleaner 11 . The photosensitive drum 8 is rotatable about its axis extending in the left-to-right direction and is rotatably supported to the drum unit 5 . During image formation, the photosensitive drum 8 is rotated in a counterclockwise direction when viewed from its left side (i.e., in a counterclockwise direction in FIG. 1 ). The charging roller 9 , the developing device 10 and the drum cleaner 11 are disposed to surround the photosensitive drum 8 . More specifically, as shown in FIG. 1 , the charging roller 9 is disposed at a position diagonally upward and frontward of the photosensitive drum 8 and in contact with the photosensitive drum 8 . The developing device 10 has a lower end portion that opposes the photosensitive drum 8 at a position rearward of the same. The drum cleaner 11 confronts the photosensitive drum 8 at a position frontward of the photosensitive drum 8 . The drum unit 5 for the color of black positioned rearmost in the front-to-rear direction (hereinafter to be referred to as the drum unit 5 K) is further provided with a belt cleaner 12 . A toner cartridge 13 for storing toner therein is detachably mountable on the developing device 10 from above. As shown in FIG. 3 , when the drawer frame 3 is in the pull-out position, the toner cartridge 13 is integrally detachable with the drum unit 5 relative to the drawer frame 3 . Further, when the drawer frame 3 is in the pull-out position, the toner cartridge 13 alone is also removable from the drawer frame 3 , while the drum unit 5 remains mounted on the drum unit 5 , as shown in FIG. 4 . Within the main casing 2 , an exposure device 14 , an intermediate transfer belt 15 , a sheet feed cassette 22 and a fixing unit 23 are also provided, as shown in FIG. 1 . The exposure device 14 is disposed at an uppermost portion of the main casing 2 . The exposure device 14 is configured to irradiate four laser beams corresponding to the four colors used in the color printer 1 toward surfaces of the photosensitive drums 8 . Instead of the exposure device 14 , four LED arrays may be provided for the photosensitive drums 8 . As each photosensitive drum 8 rotates, the corresponding charging roller 9 applies a uniform charge to the surface of the photosensitive drum 8 . Subsequently, the laser beams irradiated from the exposure device 14 selectively expose the surfaces of the photosensitive drums 8 to light. As a result of exposure to light, an electrostatic latent image is formed on the surface of each photosensitive drum 8 . When toner is supplied to the electrostatic latent image from the developing device 10 , the electrostatic latent image is developed into a toner image. The intermediate transfer belt 15 is disposed below the drawer frame 3 in the accommodated position. The intermediate transfer belt 15 is an endless belt, and mounted around three rollers 16 , 17 and 18 in a taut state. The two rollers 16 , 17 are disposed so as to oppose each other in the front-to-rear direction and at positions identical to each other with respect to a vertical direction. The two rollers 16 , 17 are separated from each other in the front-to-rear direction by a prescribed distance that is substantially identical to a length of the drawer frame 3 in the front-to-rear direction. The remaining roller 18 is disposed diagonally downward and frontward of the roller 17 that is positioned at the rear side in the main casing 2 . The intermediate transfer belt 15 thus defines a planar portion 19 between the rollers 16 , 17 (upper portion of the endless intermediate transfer belt 15 ), the planar portion 19 extending in the front-to-rear direction and the left-to-right direction. The planar portion 19 is in contact with each of the photosensitive drums 8 and a first cleaning roller 75 (to be described later). Four primary transfer rollers 20 are disposed within a loop of the intermediate transfer belt 15 such that each primary transfer roller 20 is in confrontation with each photosensitive drum 8 via the planar portion 19 . During image formation, the intermediate transfer belt 15 circularly moves in a clockwise direction when viewed from its left side. Due to the primary transfer rollers 20 , the toner images formed on the surfaces of the photosensitive drums 8 are superimposed onto the intermediate transfer belt 15 , sequentially from the black toner image. A colored toner image is thus formed on the intermediate transfer belt 15 . A secondary transfer roller 21 is disposed rearward of the roller 17 so as to oppose the same via the intermediate transfer belt 15 . The secondary transfer roller 21 is in contact with the intermediate transfer belt 15 . The sheet feed cassette 22 is disposed at a lower portion of the main casing 2 . The sheet feed cassette 22 accommodates therein sheets of paper P. The paper P accommodated in the sheet feed cassette 22 is conveyed toward a position where the intermediate transfer belt 15 is in contact with the secondary transfer roller 21 by various rollers. Due to the secondary transfer roller 21 , the colored toner image formed on the intermediate transfer belt 15 is transferred onto the paper P passing between the intermediate transfer belt 15 and the secondary transfer roller 21 . The fixing unit 23 is disposed rearward of the drawer frame 3 in the accommodated position. The paper P on which the colored toner image has been transferred is then conveyed to the fixing unit 23 whereby the toner image is fixed to the paper P by heat and pressure. After the toner image has been fixed to the paper P in the fixing unit 23 , various rollers discharge the paper P onto a discharge tray 24 formed on a top surface of the main casing 2 . Next, a detailed configuration of the drum unit 5 K will be described with reference to FIGS. 5 through 14 as an example for explaining a configuration of the drum unit 5 . The drum unit 5 K has a configuration identical to those of other three drum units 5 (for yellow, magenta and cyan) except that the belt cleaner 12 and a second conveyor unit 101 (described later) are provided only in the drum unit 5 K. As shown in FIGS. 5 and 6 , the drum unit 5 K includes a left side plate 31 and a right side plate 32 arranged in opposition to each other in the left-to-right direction. The charging roller 9 , the developing device 10 , the drum cleaner 11 and the belt cleaner 12 (shown in FIG. 1 ) are interposed between the left side plate 31 and the right side plate 32 and integrally held to the left side plate 31 and the right side plate 32 . The left side plate 31 extends upward and has an upper end portion facing the toner cartridge 13 from leftward of the same. The right side plate 32 extends upward and has an upper end portion facing the developing device 10 from rightward of the same such that a space above the developing device 10 is exposed rearward so as to be used as a space for accommodating the toner cartridge 13 therein. The developing device 10 includes a developing device frame 41 extending between the left side plate 31 and the right side plate 32 , as shown in FIGS. 5 and 6 . A developing chamber 42 is formed in the developing device frame 41 , as shown in FIGS. 7 and 8 . The developing chamber 42 has a lower end portion that is open toward the photosensitive drum 8 . Within the developing chamber 42 , a developing roller 43 , a supply roller 46 , a thickness-regulating blade 49 and an auger 50 are disposed. The developing roller 43 is positioned at the lower end portion of the developing chamber 42 . The developing roller 43 includes a cylindrical-shaped developing roller main body 44 and a developing roller shaft 45 extending in the left-to-right direction. The developing roller main body 44 has an axis extending in the left-to-right direction, and the developing roller shaft 45 penetrates through the developing roller main body 44 along the axis thereof. The developing roller main body 44 has an outer circumferential surface a portion of which is exposed outside of the developing chamber 42 and is in contact with the surface of the photosensitive drum 8 . The developing roller shaft 45 penetrates through left and right side plates (not shown) of the developing device frame 41 and is rotatably supported to the same. The developing roller shaft 45 has widthwise ends in the left-to-right direction that are supported to the left side plate 31 and the right side plate 32 respectively. The supply roller 46 includes a cylindrical-shaped supply roller main body 47 and a supply roller shaft 48 extending in the left-to-right direction. The supply roller main body 47 has an axis extending in the left-to-right direction, and the supply roller shaft 48 penetrates through the supply roller main body 47 along the axis of the supply roller main body 47 . The supply roller 46 is disposed diagonally upward and rearward of the developing roller 43 such that the supply roller main body 47 is in contact with the developing roller main body 44 . The supply roller shaft 48 is rotatably supported to the left and side plates of the developing device frame 41 . The thickness-regulating blade 49 has a thin plate-like shape. The thickness-regulating blade 49 has a base end held to the developing device frame 41 and another free end that is movable due to resilient deformation of the thickness-regulating blade 49 . The free end of the thickness-regulating blade 49 is in contact with the developing roller main body 44 from upward of the same. The auger (feeder screw) 50 is disposed at a position diagonally upward and frontward of the supply roller 46 . The auger 50 includes an auger shaft 51 extending in the left-to-right direction and an auger screw 52 formed on and along the auger shaft 51 in a spiral manner. The auger shaft 51 is rotatably supported to the left side plate 31 and the right side plate 32 . As the auger 50 rotates, toner supplied within the developing chamber 42 from the toner cartridge 13 is conveyed in the left-to-right direction and dispersed along the auger 50 . As the supply roller 46 rotates, the toner is supplied onto the developing roller main body 44 from the supply roller main body 47 . As the developing roller 43 rotates, the toner on the developing roller main body 44 enters between the free end of the thickness-regulating blade 49 and the developing roller main body 44 , and is maintained on the developing roller main body 44 as a thin layer of uniform thickness. The developing device frame 41 is further formed with a plate-shaped partitioning wall 53 positioned between the developing chamber 42 and the space for accommodating the toner cartridge 13 . The partitioning wall 53 curves in an arcuate shape, with its convex side facing the developing chamber 42 . The partitioning wall 53 is formed with a communication port 54 at a position circumferentially center of the partitioning wall 53 . The communication port 54 penetrates through the partitioning wall 53 so as to allow the communication port 54 to be in fluid communication with the developing chamber 42 . The auger 50 is positioned within the developing chamber 42 at a position in confrontation with the communication port 54 . A plate-shaped developing-side shutter 55 is provided on the partitioning wall 53 . The developing-side shutter 55 has an accurate shape protruding toward the developing chamber 42 substantially in conformance with the arcuate-shaped outline of the partitioning wall 53 . The developing-side shutter 55 is formed with a shutter opening 56 at a position corresponding to the position of the communication port 54 formed on the partitioning wall 53 . The developing-side shutter 55 is movable along the partitioning wall 53 between an open position where the shutter opening 56 is in communication with the communication port 54 and a closed position where the shutter opening 56 is prevented from communicating with the communication port 54 . The drum cleaner 11 includes a drum cleaner casing 61 extending in the left-to-right direction. The drum cleaner casing 61 spans across the left side plate 31 and the right side plate 32 , as shown in FIG. 9 . The drum cleaner casing 61 includes a cleaner opening 62 and a waste toner chamber 63 . The cleaner opening 62 spans an entire width of the photosensitive drum 8 in the left-to-right direction so as to face the same. The waste toner chamber 63 is formed within the drum cleaner casing 61 and in fluid communication with the cleaner opening 62 . As shown in FIGS. 7 through 9 , an auger 64 is disposed within the waste toner chamber 63 . The auger 64 includes an auger shaft 65 extending in the left-to-right direction and an auger screw 66 provided on and along the auger shaft 65 in a spiral manner. The drum cleaner casing 61 has a right side wall 67 that closes (covers) the waste toner chamber 63 at a right side thereof, as shown in FIG. 9 . The auger shaft 65 has a right end portion penetrating the right side wall 67 and is rotatably supported to the same. The auger shaft 65 has a left end portion that is rotatably supported to an opposing wall 92 (described later). The drum cleaner 11 further includes a scraper 69 as shown in FIGS. 7 and 8 . The scraper 69 has a plate-like shape extending in the left-to-right direction and in the vertical direction. The scraper 69 has an upper en portion that is fixed to the drum cleaner casing 61 , and a lower portion that is in contact with the surface of the photosensitive drum 8 within the cleaner opening 62 . In accordance with the rotation of the photosensitive drum 8 , the toner remaining deposited on the surface of the photosensitive drum 8 after the toner image is transferred onto the intermediate transfer belt 15 is scraped off from the surface of the photosensitive drum 8 by the scraper 69 as waste toner. The waste toner scraped off from the photosensitive drum 8 is received within the waste toner chamber 63 via the cleaner opening 62 . Subsequently, as the auger 64 rotates, the auger 64 (the auger screw 66 ) conveys the waste toner leftward within the waste toner chamber 63 . The belt cleaner 12 includes a belt cleaner casing 71 . As shown in FIGS. 7 and 8 , the belt cleaner casing 71 includes a first peripheral wall 72 and a second peripheral wall 73 . The first peripheral wall 72 curves in an arcuate shape in cross-section, with its convex side facing upward. The first peripheral wall 72 has a front end portion from which the second peripheral wall 73 extends downward. The second peripheral wall 73 has a substantially U-shape in cross-section, whose bottom end portion projecting downward. As shown in FIG. 10 , each of the first peripheral wall 72 and the second peripheral wall 73 has a left end portion connected to the left side plate 31 . The belt cleaner casing 71 also includes a right side wall 74 (see FIG. 10 ) defining right end portions of the first peripheral wall 72 and the second peripheral wall 73 . The right side wall 74 is spaced away from the right side plate 32 of the drum unit 5 K. As shown in FIGS. 7 and 8 , the first cleaning roller 75 is disposed within the drum cleaner casing belt cleaner casing 71 at a position between rear end portions of the first peripheral wall 72 and the second peripheral wall 73 . The first cleaning roller 75 includes a cylindrical-shaped cleaning roller main body 76 and a cleaning roller shaft 77 extending in the left-to-right direction. The cleaning roller main body 76 has an axis extending in the left-to-right direction, and the cleaning roller shaft 77 penetrates through the cleaning roller main body 76 along the axis of thereof The cleaning roller shaft 77 is rotatably supported to the belt cleaner casing 71 . The belt cleaner casing 71 is formed with a roller accommodation chamber 78 surrounded by the first peripheral wall 72 , and a waste toner chamber 79 surrounded by the second peripheral wall 73 . A second cleaning roller 80 is further disposed within the roller accommodation chamber 78 . The second cleaning roller 80 includes a cylindrical-shaped cleaning roller main body 81 and a cleaning roller shaft 82 extending in the left-to-right direction. The cleaning roller main body 81 has an axis extending in the left-to-right direction, and the cleaning roller shaft 82 penetrates through the cleaning roller main body 81 along the axis thereof The cleaning roller main body 81 is in contact with the cleaning roller main body 76 of the first cleaning roller 75 at a position diagonally upward and frontward of the cleaning roller main body 76 . As shown in FIG. 10 , the cleaning roller shaft 82 has a right end portion that is rotatably supported to the right side plate 32 , and a left end portion that is rotatably supported to the belt cleaner casing 71 . Within the waste toner chamber 79 , an auger 83 is rotatably disposed, as shown in FIGS. 7 , 8 , 10 . The auger 83 includes an auger shaft 84 extending in the left-to-right direction and an auger screw 85 formed on and along the auger shaft 84 in a spiral manner. As shown in FIG. 10 , the auger shaft 84 has a right end portion penetrating through the right side wall 74 and rotatably supported to the right side plate 32 , and a left end portion rotatably supported to an opposing wall 102 (described later). Further, as shown in FIGS. 7 and 8 , a scraper 86 is disposed at a boundary area between the roller accommodation chamber 78 and the waste toner chamber 79 . The scraper 86 has a plate-like shape extending in the left-to-right direction. The scraper 86 has an upper en portion that is fixed to the belt cleaner casing 71 , and a lower portion that is in contact with a surface of the cleaning roller main body 81 of the second cleaning roller 80 at a position diagonally downward and frontward of the cleaning roller main body 81 . The cleaning roller main body 76 of the first cleaning roller 75 is in contact with the intermediate transfer belt 15 , as described earlier (see FIG. 1 ). Further, as also shown in FIG. 1 , a backup roller 87 is disposed within the loop of the intermediate transfer belt 15 at a position in confrontation with the first cleaning roller 75 via the intermediate transfer belt 15 . Toner still remaining on the intermediate transfer belt 15 after the toner image has been transferred to the paper P (i.e., waste toner) is carried on a surface of the cleaning roller main body 76 of the first cleaning roller 75 when the cleaning roller main body 76 confronts the intermediate transfer belt 15 in accordance with the circular movement of the intermediate transfer belt 15 . The waste toner is then transferred from the surface of the cleaning roller main body 76 of the first cleaning roller 75 to the surface of the cleaning roller main body 81 of the second cleaning roller 80 . The waste toner is scraped off from the surface of the cleaning roller main body 81 by the scraper 86 , and is received within the waste toner chamber 79 . Subsequently, as the auger 83 rotates, the auger 83 (the auger screw 85 ) conveys the waste toner leftward within the waste toner chamber 79 . Incidentally, instead of the belt cleaner 12 , a scraper may be provided so as to be in slidingly contact with the intermediate transfer belt 15 . In this configuration, the waste toner on the intermediate transfer belt 15 can be scraped off therefrom by the scraper. As shown in FIG. 11 , on an outer surface (left side surface) of the left side plate 31 of the drum unit 5 K, a first conveying unit 91 is provided. The first conveying unit 91 has an elongated shape, extending diagonally upward and rearward from a lower front end portion to an upper end portion of the left side plate 31 . The first conveying unit 91 includes the opposing wall 92 and a peripheral wall 93 . The opposing wall 92 is disposed in opposition to the left side plate 31 and is spaced away therefrom. The peripheral wall 93 is formed along an entire periphery of the opposing wall 92 . As shown in FIGS. 9 and 12 , a space 94 is defined by the outer surface of the left side plate 31 , the opposing wall 92 and the peripheral wall 93 , and serves as a waste toner chamber through which waste toner is conveyed. Belt shafts 95 , 96 are respectively disposed at upper and lower end portions within the waste toner chamber 94 . The belt shafts 95 , 96 extend in the left-to-right direction and are rotatably supported to the opposing wall 92 . An endless toner conveying belt 98 is mounted on the belt shafts 95 , 96 . The toner conveying belt 98 has an outer circumferential surface on which a plurality of ribs 97 is formed at regular intervals. The toner conveying belt 98 is circularly moved in a clockwise direction in a left side view, as indicated by an arrow in FIG. 12 . The belt shaft 95 has a left end protruding leftward from the opposing wall 92 . The left end of the belt shaft 95 protruding from the opposing wall 92 is fitted with a gear 99 , as shown in FIG. 11 . As shown in FIG. 9 , the waste toner chamber 94 is in fluid communication with the waste toner chamber 63 of the drum cleaner 11 . Therefore, the waste toner conveyed leftward within the waste toner chamber 63 by the auger 64 flows into the waste toner chamber 94 . The waste toner flowing into the waste toner chamber 94 is then conveyed upward by the ribs 97 of the toner conveying belt 98 in accordance with the circular movement of the toner conveying belt 98 . Further, as shown in FIG. 11 , on the outer surface (left side surface) of the left side plate 31 of the drum unit 5 K, the second conveyor unit 101 is provided. The second conveyor unit 101 has an elongated shape, extending diagonally upward and frontward from a lower rear end portion to the upper end portion of the left side plate 31 . The second conveyor unit 101 includes an opposing wall 102 and a peripheral wall 103 . The opposing wall 102 is disposed in opposition to the left side plate 31 and is spaced away therefrom. The peripheral wall 103 is formed along an entire periphery of the opposing wall 102 . As shown in FIGS. 10 and 12 , a space 104 is defined by the outer surface of the left side plate 31 , the opposing wall 102 and the peripheral wall 103 , and serves as a waste toner chamber through which waste toner is conveyed. Belt shafts 105 , 106 are respectively disposed at upper and lower end portions within the waste toner chamber 104 . The belt shafts 105 , 106 extend in the left-to-right direction and are rotatably supported to the opposing wall 102 . An endless toner conveying belt 108 is mounted on the belt shafts 105 , 106 . The toner conveying belt 108 has an outer circumferential surface on which a plurality of protrusions 107 is formed at regular intervals. The toner conveying belt 108 is circularly moved in a clockwise direction in a left side view, as indicated by an arrow in FIG. 12 . The belt shaft 105 has a left end protruding leftward from the opposing wall 102 . The left end of the belt shaft 105 protruding from the opposing wall 102 is fitted with a gear 109 , as shown in FIG. 11 . As shown in FIG. 10 , the waste toner chamber 104 is in fluid communication with the waste toner chamber 79 of the belt cleaner 12 . Therefore, the waste toner conveyed leftward within the waste toner chamber 79 by the auger 83 flows into the waste toner chamber 104 . The waste toner flowing into the waste toner chamber 104 is then conveyed upward by the protrusions 107 in accordance with the circular movement of the toner conveying belt 108 . As shown in FIG. 12 , a communication unit 111 is provided between upper end portions of the first conveying unit 91 and the second conveyor unit 101 . The communication unit 111 has a hollow cylindrical shape, extending in the left-to-right direction and penetrating through the left side plate 31 , as shown in FIG. 13 . That is, the communication unit 111 has a left-side portion protruding leftward from the left side plate 31 , and a right-side portion protruding rightward from the left side plate 31 . As shown in FIG. 12 , the left-side portion of the communication unit 111 has a peripheral wall on which communication ports 112 , 113 are formed, the communication ports 112 , 113 penetrating through the peripheral wall. The communication port 112 is in fluid communication with the waste toner chamber 94 of the first conveying unit 91 , while the communication port 113 is in fluid communication with the waste toner chamber 104 of the second conveyor unit 101 . The right-side portion of the communication unit 111 has a peripheral wall on whose bottom portion a connecting port 114 is formed, the connecting port 114 penetrating through the peripheral wall, as shown in FIG. 13 . As shown in FIGS. 9 and 13 , a cylindrical-shaped shutter 115 is externally coupled to the peripheral wall of the right-side portion of the communication unit 111 . The shutter 115 is movable in the left-to-right direction along the peripheral wall of the right-side portion of the communication unit 111 . The shutter 115 is biased rightward by a coil spring 116 disposed between the shutter 115 and the left side plate 31 . Within the communication unit 111 , an auger 117 is rotatably disposed. The auger 117 includes an auger shaft 118 extending in the left-to-right direction and an auger screw 119 formed on and along the auger shaft 118 in a spiral manner. The auger shaft 118 has a left end portion protruding leftward from the communication unit 111 . The left end of the auger shaft 118 protruding from the communication unit 111 is fitted with a gear 120 , as shown in FIG. 11 . The gear 120 is in meshing engagement with the gears 99 , 109 . Hence, when a driving fore is inputted to the gear 120 , the driving force is transmitted to the respective gears 99 , 109 , thereby rotating the same. The rotation of the gears 99 , 109 enables the toner conveying belts 98 , 108 to circularly move. The waste toner conveyed upward by the toner conveying belt 98 within the waste toner chamber 94 flows into the communication unit 111 via the communication port 112 . The waste toner conveyed upward by the toner conveying belt 108 within the waste toner chamber 104 flows into the communication unit 111 via the communication port 113 . As the auger 117 rotates in response to input of the driving force to the gear 120 , the auger 117 (auger screw 119 ) conveys the waste toner rightward within the communication unit 111 . As shown in FIGS. 7 and 8 , the toner cartridge 13 includes a hollow cylindrical-shaped inner casing 121 and an outer casing 122 that accommodates therein the inner casing 121 . The outer casing 122 also has a hollow cylindrical shape. A partitioning wall 123 is formed within the inner casing 121 . The partitioning wall 123 partitions an internal space of the inner casing 121 into a toner accommodation chamber 124 and a waste toner accommodation chamber 125 . Toner to be supplied to the developing device 10 is stored within the toner accommodation chamber 124 , while collected waste toner is stored within the waste toner accommodation chamber 125 . On the inner casing 121 , an inner outlet 126 is formed for allowing fluid communication between inside and outside of the toner accommodation chamber 124 . The inner outlet 126 is positioned such that the inner outlet 126 is in coincidence with the communication port 54 of the partitioning wall 53 when the toner cartridge 13 is mounted on the partitioning wall 53 of the developing device frame 41 . As shown in FIGS. 13 and 14 , the inner casing 121 has a left end face on which a recessed portion 127 is formed. The recessed portion 127 is protruding inward (toward the inner space of the inner casing 121 ) from the left end face of the inner casing 121 . The recessed portion 127 has a circular-shaped side view, having an inner diameter greater than an outer diameter of the communication unit 111 but smaller than an outer diameter of the shutter 115 . The recessed portion 127 has a bottom end on which a discharging port 128 is formed. The discharging port 128 opens downward and is in fluid communication with the waste toner accommodation chamber 125 . Within the recessed portion 127 , a shutter 129 is movably disposed for opening and closing the discharging port 128 . The shutter 129 is movable in the left-to-right direction, and integrally includes a cylindrical portion 130 and an abutment portion 131 . The cylindrical portion 130 has an outer diameter substantially identical to the inner diameter of the recessed portion 127 . The abutment portion 131 covers a left end of the cylindrical portion 130 . A coil spring 132 is disposed between the abutment portion 131 and the recessed portion 127 such that the shutter 129 is biased leftward by the coil spring 132 . Within the toner accommodation chamber 124 , an agitator 133 is disposed, as shown in FIGS. 7 and 8 . The agitator 133 includes an agitator shaft 134 extending in the left-to-right direction, and an agitating film 135 held to the agitator shaft 134 . Within the waste toner accommodation chamber 125 , an auger 136 is rotatably disposed. As shown in FIG. 13 , the auger 136 includes an auger shaft 137 extending in the left-to-right direction and an auger screw 138 formed on and along the auger shaft 137 in a spiral manner. As shown in FIGS. 7 and 8 , on an outer circumferential surface of the outer casing 122 , an outer outlet 139 is formed. The outer outlet 139 is positioned such that the outer outlet 139 is in coincidence with the inner outlet 126 with respect to the left-to-right direction. Hence, as the outer casing 122 is made to rotate (slidingly move) relative to the inner casing 121 , the inner outlet 126 takes either a position where the inner outlet 126 confronts the outer outlet 139 and is in communication with the same, or another position where the inner outlet 126 is not in confrontation with the outer outlet 139 . The outer outlet 139 is also positioned such that the outer outlet 139 is in confrontation with the shutter opening 56 of the developing-side shutter 55 and in communication with the same when the toner cartridge 13 is mounted on the partitioning wall 53 of the developing device frame 41 . The toner cartridge 13 is mounted within the space above the partitioning wall 53 of the developing device frame 41 (see FIG. 6 ) from a right side of the space. That is, at the time of installation of the toner cartridge 13 , the toner cartridge 13 is moved from the right side toward a left side of the space above the partitioning wall 53 . Subsequently, as shown in FIG. 13 , the recessed portion 127 and the communication unit 111 are positionally-aligned with each other such that the communication unit 111 is inserted within the recessed portion 127 provided on the left end face of the inner casing 121 . At this time, the shutter 115 coupled to the communication unit 111 is in confrontation with a peripheral end portion of the recessed portion 127 . As the toner cartridge 13 moves further leftward, the shutter 115 is brought into contact with the peripheral end portion of the recessed portion 127 and is prevented from being inserted within the recessed portion 127 , while, in the mean time, the communication unit 111 is inserted into the recessed portion 127 . As the communication unit 111 is inserted into the recessed portion 127 , the communication unit 111 pushes the shutter 129 rightward. In response, the shutter 129 is moved rightward against a biasing force of the coil spring 132 . When the shutter 129 moves to reach an inner right end portion of the recessed portion 127 , the toner cartridge 13 is stopped from moving further, the installation of the toner cartridge 13 being completed. At this time, the connecting port 114 of the communication unit 111 is in confrontation with the discharging port 128 of the toner cartridge 13 . That is, an internal space of the communication unit 111 and the waste toner accommodation chamber 125 of the toner cartridge 13 are in fluid communication with each other via the connecting port 114 and the discharging port 128 . With this configuration, the waste toner conveyed rightward by the auger 117 within the communication unit 111 flows into the waste toner accommodation chamber 125 via the connecting port 114 and the discharging port 128 . In accordance with rotation of the auger 136 disposed within the waste toner accommodation chamber 125 , the auger 136 conveys the incoming waste toner rightward. The waste toner is thus uniformly dispersed within the waste toner accommodation chamber 125 in the left-to-right direction. As shown in FIG. 8 , when the toner cartridge 13 has just been mounted within the space above the partitioning wall 53 , the communication port 54 of the partitioning wall 53 and the shutter opening 56 of the developing-side shutter 55 do not confront each other. Further, the inner outlet 126 of the inner casing 121 and the outer outlet 139 of the outer casing 122 do not confront each other, either. From this state, the outer casing 122 is then made to rotate in a counterclockwise direction in FIG. 8 . When the toner cartridge 13 is mounted on the space above the partitioning wall 53 , the outer casing 122 is connected to the developing-side shutter 55 . Therefore, when the outer casing 122 is rotated, the developing-side shutter 55 is also moved in conjunction with the rotation of the outer casing 122 . The outer casing 122 is rotated to a position where the outer outlet 139 opposes the inner outlet 126 . As a result, as shown in FIG. 7 , the outer outlet 139 is in opposition to the inner outlet 126 , and the shutter opening 56 formed on the developing-side shutter 55 is in opposition to the communication port 54 formed on the partitioning wall 53 . Thus, the toner accommodation chamber 124 and the developing chamber 42 are brought into fluid communication with each other, and the toner accommodated within the toner accommodation chamber 124 is supplied to the developing chamber 42 . As described above, the drum cleaner 11 is disposed for each photosensitive drum 8 for collecting waste toner deposited on the surface of the photosensitive drum 8 . The belt cleaner 12 for collecting waste toner on the intermediate transfer belt 15 is provided rearward of the rearmost photosensitive drum 8 for black. The toner cartridge 13 includes the toner accommodation chamber 124 for accommodating toner to be supplied to the photosensitive drum 8 , and the waste toner accommodation chamber 125 for accumulating the waste toner to be disposed. The waste toner collected at the drum cleaner 11 is conveyed toward the waste toner accommodation chamber 125 of each toner cartridge 13 by the first conveying unit 91 . The waste toner collected at the belt cleaner 12 is conveyed toward the waste toner accommodation chamber 125 of the toner cartridge 13 corresponding to the rearmost photosensitive drum 8 positioned adjacent to the belt cleaner 12 . Each waste toner accommodation chamber 125 is in fluid communication with the communication unit 111 of each drum unit 5 . The communication unit 111 that is in fluid communication with the waste toner accommodation chamber 125 of the toner cartridge 13 corresponding to the rearmost photosensitive drum 8 for black also serves to allow fluid communication between the first conveying unit 91 and the waste toner accommodation chamber 125 , and between the second conveyor unit 101 and the waste toner accommodation chamber 125 . With this configuration, the waste toner collected from the photosensitive drum 8 for black by the drum cleaner 11 is conveyed, via the first conveying unit 91 and the communication unit 111 , to the waste toner accommodation chamber 125 that is in fluid communication with the communication unit 111 . To this waste toner accommodation chamber 125 , the waste toner collected from the intermediate transfer belt 15 by the belt cleaner 12 is also conveyed via the second conveyor unit 101 and the communication unit 111 . Therefore, a separate waste toner box for storing the waste toner collected from the intermediate transfer belt 15 is not necessary. The color printer 1 can be thus made compact. Further, the waste toner collected from both of the photosensitive drum 8 and the intermediate transfer belt 15 can be disposed at a time just by replacing the toner cartridge 13 corresponding to the black photosensitive drum 8 . Furthermore, since the intermediate transfer belt 15 is not required to be removed for replacing each toner cartridge 13 , efforts required to dispose the waste toner can be greatly reduced. Further, the communication unit 111 is connected to the left end face of the toner cartridge 13 . The waste toner collected by the drum cleaner 11 and the belt cleaner 12 is conveyed first leftward by the augers 64 , 83 , then upward by the first conveying unit 91 and the second conveyor unit 101 , and finally to the waste toner accommodation chamber 125 from its left side via the communication unit 111 . The auger 136 provided within the waste toner accommodation chamber 125 conveys the waste toner flowing from the communication unit 111 into the waste toner accommodation chamber 125 rightward. Therefore, the waste toner can be dispersed in the left-to-right direction within the waste toner accommodation chamber 125 . As a result, the waste toner is prevented from accumulating at an area in the vicinity of the communication unit 111 within the waste toner accommodation chamber 125 . The flow of the waste toner from the communication unit 111 into the waste toner accommodation chamber 125 can be made smooth and secured. Further, each photosensitive drum 8 , the drum cleaner 11 , the communication unit 111 , the first conveying unit 91 and the second conveyor unit 101 are integrally supported to the left side plate 31 and the right side plate 32 . More specifically, the side plates 31 , 32 retaining the rearmost photosensitive drum 8 for black integrally support the drum cleaner 11 , the belt cleaner 12 , the first conveying unit 91 and the second conveyor unit 101 . The pair of side plates 31 , 32 retaining each of the remaining three photosensitive drums 8 supports the drum cleaner 11 corresponding to the photosensitive drum 8 , and the first conveying unit 91 . Therefore, the black photosensitive drum 8 , the drum cleaner 11 , the belt cleaner 12 , the first conveying unit 91 and the second conveyor unit 101 can be treated as an integral unit, while each of the other three photosensitive drums 8 , its drum cleaner 11 and first conveying unit 91 can be treated as an integral unit. Further, the four toner cartridges 13 can be integrally pulled out from the main casing 2 via the drawer frame 3 . Therefore, replacement of the toner cartridge 13 for black that is positioned rearmost in the front-to-rear direction can be facilitated. Although the present invention has been described with respect to the specific embodiment thereof, it will be appreciated by one skilled in the art that a variety of changes may be made without departing from the scope of the invention.

An image forming device includes photosensitive drums, developer cartridges, an endless belt, first collecting units, first conveying units, a second collecting unit, a second conveying unit and communication portions. The photosensitive drums form a drum array including a leading photosensitive drum. Each developer cartridge has a waste developer accommodating chamber. Each first collecting unit collects waste developer on the corresponding photosensitive drum. Each first conveying unit conveys the waste developer toward the waste developer accommodating chamber. The second collecting unit collects waste developer on the endless belt. The second conveying unit conveys the waste developer toward the waste developer accommodating chamber. Each communication portion allows fluid communication between the first conveying unit and the waste developer accommodating chamber. One of the communication portions associated with the leading photosensitive drum also allows fluid communication between the second conveying unit and the waste developer accommodating chamber.

CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims priority from Korean Patent Application No. 10-2015-0120546, filed on Aug. 26, 2015 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference. BACKGROUND [0002] Apparatuses, methods and systems consistent with exemplary embodiments relate to plasma generation, and more particularly, to a plasma generation apparatus that is operated by a radio frequency (RF) pulse power supply. [0003] When wafer processing such as etching and deposition of a wafer is performed using an RF pulse plasma generation apparatus, an electron temperature may be lowered more than a case where continuous wave (CW) plasma is used. Thus, the possibility of the wafer being damaged due to excessive decomposition of injected reactive gas may be reduced. However, a process error that may occur as electrons are concentrated in a specific area in a chamber. SUMMARY [0004] One or more exemplary embodiments provide a plasma generation apparatus for improving process distribution. [0005] According to an aspect of an exemplary embodiment, there is provided a plasma generation apparatus including: a chamber defining a reaction space that is isolated from an external environment; an upper electrode provided in an upper portion of the chamber; a lower electrode provided in a lower portion of the chamber; a sidewall electrode provided at a sidewall of the chamber; a radio frequency (RF) pulse power supplier configured to supply RF pulse power to at least one from among the upper electrode and the lower electrode; and a direct current (DC) pulse power supplier configured to supply DC pulse power to the sidewall electrode. [0006] An on-time of the DC pulse power, during which the DC pulse power is supplied to the sidewall electrode, may be substantially equal to an off-time of the RF pulse power, during which the RF pulse power is not supplied to the upper electrode and the lower electrode. [0007] A first section of an on-time of the DC pulse power, during which the DC pulse power is supplied to the sidewall electrode, may overlap with an off-time of the RF pulse power, during which the RF pulse power is not supplied to the upper electrode and the lower electrode, and a second section of the on-time of the DC pulse power other than the first section may overlap with a portion of an on-time of the RF pulse power, during which the RF pulse power is supplied to the at least one from among the upper electrode and the lower electrode. [0008] A voltage value of the DC pulse power may be substantially constant during an on-time of the DC pulse power supplied by the DC pulse power supplier to the sidewall electrode. [0009] A voltage value of the DC pulse power may vary during an on-time of the DC pulse power supplied by the DC pulse power supplier to the sidewall electrode. [0010] The DC pulse power supplier may be further configured to, when electron density in a central area of the chamber is higher than an electron density in an outer area of the chamber surrounding the central area, supply the DC pulse power having a positive voltage value to the sidewall electrode. [0011] The DC pulse power supplier may be further configured to, when electron density in a central area of the chamber is lower than an electron density in an outer area surrounding the central area, supply the DC pulse power having a negative voltage value to the sidewall electrode. [0012] The plasma generation apparatus may further include a controller configured to supply a first pulse signal to the RF pulse power supplier to control supply of the RF pulse power by the RF pulse supplier and supply a second pulse signal synchronized with the first pulse signal to the DC pulse power supplier to control supply of the DC pulse power by the DC pulse power supplier. [0013] The plasma generation apparatus may further include a monitoring unit configured to monitor a first electron density in a central region of the chamber and a second electron density in an outer area of the chamber surrounding the central region, and the controller may be further configured to adjust a voltage value of the DC pulse power based on the first electron density and the second electron density. [0014] The plasma generation apparatus may further include a database configured to store a correlation model between the DC pulse power and an electron density in the chamber, and the controller may be further configured to adjust a voltage value of the DC pulse power based on the correlation model stored in the database. [0015] According to an aspect of another exemplary embodiment, there is provided a plasma generation apparatus including: a chamber defining a reaction space that is isolated from an external environment; an upper electrode provided in an upper portion of the chamber; a lower electrode provided in a lower portion of the chamber; a sidewall electrode provided at a sidewall of the chamber; a first radio frequency (RF) pulse power supplier configured to supply first RF pulse power to the upper electrode; a second RF pulse power supplier configured to supply second RF pulse power to the lower electrode; and a direct current (DC) power supplier configured to supply DC power to the sidewall electrode during an off-time of the first RF pulse power and an off-time of the second RF pulse power. [0016] There may be a phase difference between the first RF pulse power and the second RF pulse power, and the DC power supplier may be further configured to supply the DC power to the sidewall electrode when both the first RF pulse power and the second RF pulse power are pulsed off. [0017] There may be a phase difference between the first pulse power and the second RF pulse power, and the DC power supplier may be further configured to supply the DC power during the off-time of the first RF pulse power or the off-time of the second RF pulse power. [0018] The plasma generation apparatus may further include a controller configured to supply synchronized first and second pulse signals to the first and second RF pulse power suppliers, respectively. [0019] The controller may be further configured the DC power so as to be synchronized with on-times and off-times of the first and second RF pulse powers. [0020] According to an aspect of another exemplary embodiment, there is provided plasma generation apparatus including: a chamber defining a reaction space; a first electrode provided in an upper or lower portion the chamber; a second electrode provided at a sidewall of the chamber; a radio frequency (RF) pulse power supplier configured to supply RF pulse power to the first electrode, the RF pulse power having an on-time during which the RF power is pulsed on and an off-time during which the RF pulse power is pulsed off; and a direct current (DC) pulse power supplier configured to supply DC pulse power to the second electrode, the DC pulse power having an on-time during which the DC pulse power is pulsed on and an off-time during which the DC pulse power is pulsed off, wherein the on-time of the DC pulse power and the off-time of the RF pulse power overlap each other, and the off-time of the DC pulse power and the on-time of the RF pulse power overlap each other. [0021] The on-time of the DC pulse power and the on-time of the RF pulse power may not overlap each other. [0022] The on-time of the DC pulse power and the on-time of the RF pulse power may overlap each other. [0023] The DC pulse power supplier may be further configured to, when an electron density in a central area of the chamber is higher than an electron density in an area surrounding the central area, supply the DC pulse power having a positive voltage during an on-time of the DC pulse power. [0024] The DC pulse power supplier may be further configured to, when electron density in a central area of the chamber is lower than an electron density in an area surrounding the central area, supply the DC pulse power having a negative voltage during an on-time of the DC pulse power. BRIEF DESCRIPTION OF THE DRAWINGS [0025] The above and/or other aspects will be more clearly understood from the following detailed description of exemplary embodiments taken in conjunction with the accompanying drawings in which: [0026] FIG. 1 is a configuration diagram of a plasma generation apparatus according to an exemplary embodiment; [0027] FIG. 2 is a timing diagram illustrating operations of an RF pulse power and a DC pulse power and electron density in a chamber which varies depending on the RF pulse power and the DC pulse power, according to an exemplary embodiment; [0028] FIGS. 3A through 3D are timing diagrams illustrating operations of an RF pulse power and a DC pulse power, according to exemplary embodiments; [0029] FIG. 4 is a configuration diagram of a plasma generation apparatus according to another exemplary embodiment; [0030] FIG. 5 is a timing diagram illustrating operations of an RF pulse power and a DC pulse power and electron density in a chamber which varies depending on the RF pulse power and the DC pulse power, according to an exemplary embodiment; [0031] FIG. 6 is a configuration diagram of a plasma generation apparatus according to another exemplary embodiment; [0032] FIG. 7 is a configuration diagram of a plasma generation apparatus according to another exemplary embodiment; [0033] FIG. 8 is a configuration diagram of a plasma generation apparatus according to another exemplary embodiment; and [0034] FIGS. 9A and 9C are timing diagrams illustrating operations of first and second RF pulse powers and a DC pulse power, according to exemplary embodiments. DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS [0035] Exemplary embodiments will be described more fully with reference to the accompanying drawings. Like reference numerals refer to like elements throughout. [0036] The inventive concept may, however, be embodied in many different forms and should not be construed as limited to the exemplary embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope to those skilled in the art. In the drawings, lengths and sizes of layers and regions may be exaggerated for clarity. [0037] It will be understood that, although the terms “first”, “second”, “third”, etc., may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings. [0038] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this inventive concept belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. [0039] In a case where a certain embodiment may be implemented in a different way, a specific sequence of processes may be different from a sequence to be described. For example, two processes sequentially described may be simultaneously performed in reality, or may be performed in a sequence opposite to the sequence to be described. [0040] As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, embodiments should not be construed as limited to the particular shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. [0041] A plasma generation apparatus according to exemplary embodiments may use a capacitively coupled plasma (CCP) method in which wafers are arranged at a point having an RF voltage applied thereto, a magnetically-enhanced RIE (CCP-MERIE) method in which the possibility of ion generation is increased by applying a magnetic field to a plasma space to thereby perform etching, an electron cyclotron resonance (ECR) method in which resonance is generated by causing a microwave frequency to be incident thereon to thereby ionize neutral particles, a transformer coupled plasma (TCP) method in which an RF coil is used but the RF coil is only wound around an upper portion of a process chamber, an inductively coupled plasma (ICP) method in which an RF coil is used but the RF coil is wound around a side surface of a process chamber, a helical plasma method in which an RF coil is used in a spiral form, a high density plasma (HDP) method in which a portion generating plasma and a portion adjusting ion energy are independently controlled, or the like. However, the inventive concept is not limited thereto, and the plasma generation apparatus may use any method insofar as the plasma generation apparatus may apply RF power in the form of a pulse. [0042] FIG. 1 is a configuration diagram of a plasma generation apparatus 100 according to an exemplary embodiment. [0043] Referring to FIG. 1 , the plasma generation apparatus 100 may include a chamber 110 , an RF pulse power supplier 120 , a DC pulse power supplier 130 , and a controller 140 . [0044] The chamber 110 provides a plasma reaction space that is isolated from an external environment and may have various sizes and forms depending on a size of a wafer W on which a process is to be performed and on process characteristics. [0045] In some exemplary embodiments, the chamber 110 may be formed of a metal, an insulator, or a combination thereof. In some exemplary embodiments, the inside of the chamber 110 may be coated with an insulator. The chamber 110 may have a rectangular parallelepiped shape or a cylindrical shape, but the inventive concept is not limited thereto. [0046] A lower electrode 112 may be disposed in a lower portion of the chamber 110 . The lower electrode 112 may function as a wafer chuck. In some exemplary embodiments, the lower electrode 112 may be an electrostatic chuck (ESC) that adsorbs and supports a wafer by an electrostatic force. Alternatively, in some exemplary embodiments, the lower electrode 112 may be a mechanical clamping type chuck or a vacuum chuck that adsorbs and supports a wafer by vacuum pressure. The lower electrode 112 may be provided with a heater that heats the wafer to a process temperature. In some exemplary embodiments, the lower electrode 112 may be grounded. [0047] An upper electrode 114 may be disposed in an upper portion of the chamber 110 . The pulse power supplier 120 that supplies an RF pulse power to the upper electrode 114 may be connected to the upper electrode 114 to generate plasma of a reaction gas. [0048] In the current exemplary embodiment, although the RF pulse power supplier 120 is connected to the upper electrode 114 and the lower electrode 112 is grounded, the inventive concept is not limited thereto. For example, unlike the embodiment shown in FIG. 1 , the upper electrode 114 may be grounded and the RF pulse power supplier 120 may be connected to the lower electrode 112 . [0049] As the RF pulse power supplier 120 supplies an RF pulse power to the upper electrode 114 , a reaction gas diffused in the chamber 110 may be changed to a plasma state to react with the wafer W disposed on the lower electrode 112 . In other words, the reaction gas is converted into plasma by the RF pulse power, which is applied to the upper electrode 114 , as soon as the reaction gas is diffused in the chamber, and the plasma comes into contact with a surface of the wafer W and thus physically or chemically reacts with the wafer W. Wafer processing processes, such as plasma annealing, etching, plasma-enhanced chemical vapor deposition, physical vapor deposition, and plasma cleaning, may be performed through such reaction. [0050] In some exemplary embodiments, the RF pulse power supplier 120 may include an RF power generator 122 and a matching unit 124 . For example, the RF power generator 122 may generate a high frequency RF power. The matching unit 124 may output a pulse-modulated RF pulse power by mixing the RF power generated by the RF power generator 122 with a pulse signal output from the controller 140 as will be described below. [0051] Accordingly, the RF pulse power supplier 120 may be operated in a pulse mode to supply pulse-modulated RF pulse power. In this manner, pulse plasma may be formed by pulsing RF power and applying the pulsed RF power to the upper electrode 114 . In other words, plasma may be generated during an on-time of a pulse and may be extinguished during an off-time of the pulse. By using the pulse plasma for wafer processing, an electron temperature may be lowered as compared to using continuous wave (CW) plasma. Thus, the incidence of wafer damage occurring due to the excessive decomposition of an injected reactive gas may be lowered. [0052] A plurality of sidewall electrodes 116 may be arranged at sidewalls of the chamber 110 . [0053] The DC pulse power supplier 130 , which supplies a DC pulse power for adjusting the density of electrons or positive ions of etching gases in the chamber 110 , may be connected to the sidewall electrodes 116 . As the DC pulse power is supplied to the sidewall electrodes 116 , electron density in a central area (C area) of the chamber 110 and electron density in an outside area (E area) surrounding the central area (C area) may be adjusted. This operation will be described in detail below with reference to FIGS. 2 and 3 . [0054] The controller 140 may be connected to the RF pulse power supplier 120 and the DC pulse power supplier 130 to control the RF pulse power supplier 120 and the DC pulse power supplier 130 . [0055] In some exemplary embodiments, the controller 140 may provide a first pulse signal to the RF pulse power supplier 120 . [0056] The matching unit 124 of the RF pulse power supplier 120 may mix an RF power, generated by the RF power generator 122 , with the first pulse signal, output from the controller 140 , and output a pulse-modulated RF pulse power. In other words, the controller 140 may control the matching unit 124 to turn-on or turn-off of the RF power so that the RF power is pulse-modulated. [0057] In some exemplary embodiments, the controller 140 may provide a second pulse signal to the DC pulse power supplier 130 . The second pulse signal may be synchronized with the first pulse signal. The DC pulse power supplier 130 may mix a DC power with the second pulse signal output from the controller 140 and output a DC pulse power. [0058] In some other exemplary embodiments, the controller 140 may control the DC pulse power supplier 130 so that the DC pulse power supplier 130 outputs a DC pulse power, according to an on-time and an off-time of the first pulse signal. For example, the controller 140 may control the DC pulse power suppler 130 so that the DC pulse power suppler 130 supplies a DC power to the sidewall electrodes 116 only during the off-time of the first pulse signal. [0059] FIG. 2 is a timing diagram illustrating operations of an RF pulse power and a DC pulse power and electron density in a chamber which varies depending on the RF pulse power and the DC pulse power, according to an exemplary embodiment. [0060] Some elements of the plasma generation apparatus 100 shown in FIG. 1 may be referred to in descriptions related to FIG. 2 . [0061] Referring to FIG. 2 , an RF pulse power RFPP may be supplied from the RF pulse power supplier 120 to the upper electrode 114 . [0062] The RF pulse power RFPP may denote that an RF power is supplied in a pulse mode. In other words, the RF power is supplied during on-time RF_To of the RF pulse power RFPP and is not supplied during off-time RF_Tf of the RF pulse power RFPP. Accordingly, plasma is generated during the on-time RF_To of the RF pulse power RFPP and is extinguished during the off-time RF_Tf of the RF pulse power RFPP. [0063] During the on-time RF_To of the RF pulse power RFPP, a frequency of the RF pulse power RFPP may be about 13.56 MHz. However, the inventive concept is not limited thereto. For example, the frequency of the RF pulse power RFPP may be selected within a frequency range that is equal to or greater than about 1 MHz and is equal to or less than about 100 MHz. [0064] A duty ratio of the RF pulse power RFPP may be, for example, 50% or more. The duty ratio may denote the ratio between the on-time RF_To and the off-time RF_Tf. For example, when the duty ratio is 60%, the on-time RF_To is 60% of the sum of the on-time RF_To and the off-time RF_Tf, and the off-time RF_Tf is 40% of the sum. When the duty ratio is 50%, the on-time RF_To is equal to the off-time RF_Tf. The duty ratio may be changed depending on a required wafer processing process, and the change of the duty ratio may have an influence on characteristics of pulse plasma to be generated. [0065] A DC pulse power DCPP 1 may be supplied from the DC pulse power supplier 130 to the sidewall electrodes 116 . [0066] The DC pulse power DCPP 1 may be synchronized with the RF pulse power RFPP. For example, the DC pulse power DCPP 1 may not be pulsing (hereinafter, referred to “pulsed off”) during the on-time RF_To of the RF pulse power RFPP and may be pulsing (hereinafter, referred to “pulsed on”) during the off-time RF_Tf of the RF pulse power RFPP. In other words, on-time DC 1 _To of the DC pulse power DCPP 1 may be substantially equal to the off-time RF_Tf of the RF pulse power RFPP, and off-time DC 1 _Tf of the DC pulse power DCPP 1 may be substantially equal to the on-time RF_To of the RF pulse power RFPP. [0067] When the on-time RF_To of the RF pulse power RFPP is equal to the off-time RF_Tf of the RF pulse power RFPP, the duty ratio (DC 1 _To/(DC 1 _To+DC 1 _Tf) of the DC pulse power DCPP 1 may be substantially equal to the duty ratio (RF_To/(RF_To+RF_Tf)) of the RF pulse power RFPP. [0068] During the on-time RF_To of the RF pulse power RFPP, electrons existing in the chamber 110 may be trapped in plasma generated by the RF pulse power RFPP. However, during the off-time RF_Tf of the RF pulse power RFPP, the plasma may be extinguished and thus the electrons may freely move without being trapped. When a DC power is supplied to the sidewall electrodes 116 during the off-time RF_Tf of the RF pulse power RFPP, as in the current embodiment, the freely movable electrons may move in a direction (+X direction or −X direction of FIG. 1 ) parallel to the upper surface of the wafer W, depending on the DC power. Specifically, a positive (+) voltage may be applied to the sidewall electrodes 116 during the on-time DC 1 _To of the DC pulse power DCPP 1 , and thus, the electrons in the chamber 110 may be affected by an attractive force from the sidewall electrodes 116 . Accordingly, as shown in FIG. 2 , central electron density Cd in the central area (C area) of the chamber 110 decreases according to time, and outside electron density Ed in the outside area (E area) of the chamber 110 increases according to time. [0069] When the DC pulse power DCPP 1 having a positive (+) voltage is supplied to the sidewall electrodes 116 in this manner, a phenomenon in which the electrons in the chamber 110 are concentrated in the central area (C area) may be mitigated, and thus, a process distribution in a central area and an edge area of the wafer W may be improved. [0070] FIGS. 3A through 3D are timing diagrams illustrating operations of an RF pulse power and a DC pulse power, according to exemplary embodiments. [0071] Repeated descriptions reference labels in FIGS. 3A through 3D that are the same as those of FIG. 2 are omitted for simplification of description. [0072] In addition, some elements of the plasma generation apparatus 100 shown in FIG. 1 may be referred to in descriptions related to FIGS. 3A through 3D . [0073] Referring to FIG. 3A , an RF pulse power RFPP may be supplied from the RF pulse power supplier 120 to the upper electrode 114 , and a DC pulse power DCPP 2 may be supplied from the DC pulse power supplier 130 to the sidewall electrodes 116 . [0074] The DC pulse power DCPP 2 may be supplied to the sidewall electrodes 116 while being synchronized with the RF pulse power RFPP and being shifted by a delay time td compared to the RF pulse power RFPP. In other words, the DC pulse power DCPP 2 may not be pulsed on directly after the RF pulse power RFPP enters into the off-time RF_Tf from the on-time RF_To, but may be pulsed on after a lapse of the delay time td. In addition, the DC pulse power DCPP 2 may not be pulsed off directly after the RF pulse power RFPP enters into the on-time RF_To from the off-time RF_Tf, but may be pulsed off after a lapse of the delay time td. [0075] When the DC pulse power DCPP 2 is supplied to the sidewall electrodes 116 while being shifted, a DC power may be supplied to be suitable for a pulse off-time even if the phase of the RF pulse power RFPP varies due to process variation. [0076] Referring to FIG. 3B , an RF pulse power RFPP may be supplied from the RF pulse power supplier 120 to the upper electrode 114 , and an DC pulse power DCPP 3 may be supplied from the DC pulse power supplier 130 to the sidewall electrodes 116 . [0077] The DC pulse power DCPP 3 may be supplied to the sidewall electrode 116 while being synchronized with the RF pulse power RFPP, and may be pulsed on in a portion of the on-time RF_To as well as the off-time RF_Tf of the RF pulse power RFPP. In other words, a first section X 1 of on-time DC 3 _To of the DC pulse power DCPP 3 may overlap with the off-time RF_Tf of the RF pulse power RFPP, and a remaining second section X 2 and X 3 other than the first section X 1 in the on-time DC 3 _To of the DC pulse power DCPP 3 may overlap with a portion of the on-time RF_To of the RF pulse power RFPP. [0078] Specifically, the DC pulse power DCPP 3 may be pulsed on for a delay time td 1 before the RF pulse power RFPP enters into the off-time RF_Tf from the on-time RF_To, and may be pulsed off for a delay time td 2 after the RF pulse power RFPP enters into the on-time RF_To from the off-time RF_Tf. In this case, the on-time DC 3 _To of the DC pulse power DCPP 3 may be longer than the off-time RF_Tf of the RF pulse power RFPP. [0079] When the on-time DC 3 _To of the DC pulse power DCPP 3 overlaps with a portion of the on-time RF_To of the RF pulse power RFPP in this manner, a sufficient DC power may be supplied even while the RF pulse power RFPP may be distorted or offset due to a reflected wave. [0080] Referring to FIG. 3C , an RF pulse power RFPP may be supplied from the RF pulse power supplier 120 to the upper electrode 114 , and a DC pulse power DCPP 4 may be supplied from the DC pulse power supplier 130 to the sidewall electrodes 116 . [0081] The DC pulse power DCPP 4 may be supplied to the sidewall electrode 116 while being synchronized with the RF pulse power RFPP, and may be pulsed on only in a portion of the off-time RF_Tf of the RF pulse power RFPP. For example, the DC pulse power DCPP 4 may be pulsed on for a delay time td 3 after the RF pulse power RFPP enters into_the off-time RF_Tf from the on-time RF_To, and may be pulsed off for a delay time td 4 before the RF pulse power RFPP enters into the on-time RF_To from the off-time RF_Tf. [0082] When the DC pulse power DCPP 4 is pulsed on only in a portion of the off-time RF_Tf of the RF pulse power RFPP, the DC pulse power DCPP 4 may be supplied within a range that does not have an influence on a plasma processing process that may be performed during the on-time RF_To of the RF pulse power RFPP. [0083] Referring to FIG. 3D , an RF pulse power RFPP may be supplied from the RF pulse power supplier 120 to the upper electrode 114 , and an DC pulse power DCPP 5 may be supplied from the DC pulse power supplier 130 to the sidewall electrodes 116 . [0084] When the DC pulse power DCPP 5 is supplied to the sidewall electrode 116 , as in the current embodiment, electrons, which may freely move during the off-time RF-Tf of the RF pulse power RFPP, may move in a direction (+X direction or −X direction of FIG. 1 ) parallel to the upper surface of the wafer W, depending to the DC pulse power DCPP 5 . Specifically, a negative (−) voltage may be applied to the sidewall electrodes 116 during the on-time DC 5 _To of the DC pulse power DCPP 5 , and thus, electrons in the chamber 110 may be affected by a repulsive force from the sidewall electrodes 116 . Accordingly, as shown in FIG. 3D , central electron density Cd in the central area (C area) of the chamber 110 increases according to time, and outside electron density Ed in the outside area (E area) of the chamber 110 decreases according to time. [0085] When the DC pulse power DCPP 5 having a negative (−) voltage is supplied to the sidewall electrodes 116 in this manner, a phenomenon in which the electrons in the chamber 110 are concentrated in the outside area (E area) may be mitigated, and thus, a process distribution in a central area and an edge area of the wafer W may be improved. [0086] In the current embodiment of FIG. 3D , although the DC pulse power DCPP 5 is pulsed off during the on-time RF-To of the RF pulse power RFPP and is pulsed on during the off-time RF-Tf of the RF pulse power RFPP, the DC pulse power DCPP 5 may be supplied to the sidewall electrodes 115 while being more shifted by a certain time than the RF pulse power RFPP, similar to the case described above with reference to FIG. 3A . [0087] In some exemplary embodiments, the DC pulse power DCPP 5 may be pulsed on in a portion of the on-time RF-To as well as the off-time RF-Tf of the RF pulse power RFPP, similar to the case described above with reference to FIG. 3B . [0088] In some other exemplary embodiments, the DC pulse power DCPP 5 may be pulsed on in a portion of the off-time RF-Tf of the RF pulse power RFPP, similar to the case described above with reference to FIG. 3C . [0089] FIG. 4 is a configuration diagram of a plasma generation apparatus 200 according to another exemplary embodiment. FIG. 5 is a timing diagram illustrating an operation of an RF pulse power and an operation of a DC pulse power according to an exemplary embodiment and electron density in a chamber which varies depending on the RF pulse power and the DC pulse power. [0090] Referring to FIGS. 4 and 5 , the plasma generation apparatus 200 may include a chamber 110 , an RF pulse power supplier 120 , a DC pulse power supplier 230 , a controller 240 , and a monitoring unit 250 . [0091] The monitoring unit 250 may monitor the density of electrons existing in the chamber 110 . For example, the monitoring unit 250 may monitor central electron density Dc in a central area (C area) of the chamber 110 and outside electron density Ed in an outside area (E area) of the chamber 110 in real time. [0092] In some exemplary embodiments, the monitoring unit 250 may transmit data, which relates to the central electron density Cd and the outside electron density Ed, to the controller 240 . The controller 240 may adjust a voltage value of a DC pulse power DCPP 6 that is supplied to the sidewall electrodes 116 by the DC pulse power supplier 230 , based on the central electron density Cd and the outside electron density Ed received from the monitoring unit 250 . [0093] Referring to the timing diagram shown in FIG. 5 , if the central electron density Cd is higher than the outside electron density Ed at the moment (for example, at times ta 1 , ta 2 , and ta 4 ) when the RF pulse power RFPP that is supplied by the RF pulse power supplier 120 enters into the off-time RF_Tf from the on-time RF_To (ta 1 , ta 2 , ta 3 , and ta 4 ), the DC pulse power DCPP 6 may supply a positive (+) voltage during a pulse on-time thereof. On the contrary, if the central electron density Cd is lower than the outside electron density Ed at the moment (for example, at times ta 3 ) when the RF pulse power RFPP enters into the off-time RF_Tf from the on-time RF_To (ta 1 , ta 2 , ta 3 , and ta 4 ), the DC pulse power DCPP 6 may supply a negative (−) voltage during a pulse on-time thereof. [0094] By monitoring the density of electrons existing in the chamber 110 and adjusting a voltage value of the DC pulse power DCPP 6 based on the monitored density of electrons, a process distribution in a central area and an edge area of the wafer W may be improved. [0095] FIG. 6 is a configuration diagram of a plasma generation apparatus 300 according to another exemplary embodiment. [0096] Referring to FIG. 6 , the plasma generation apparatus 300 may include a chamber 110 , an RF pulse power supplier 120 , a DC pulse power supplier 330 , a controller 340 , and a memory storing a database 360 . [0097] A correlation model between a DC pulse power, which may be supplied by the DC pulse power supplier 330 , and an electron density (for example, the central electron density Cd and the outside electron density Ed of FIG. 5 ) may be stored in the database 360 , and the correlation model may be obtained through a test. [0098] The correlation model between the DC pulse power and the electron density may include a correlation established by a non-modeling approach, such as a decision tree analysis algorithm, as well as a modeling approach such as a neural network algorithm. [0099] In some exemplary embodiments, the correlation model between the DC pulse power and the electron density may be established through any of various algorithms, such as a multiple linear regression algorithm, a multiple nonlinear regression algorithm, a neural network algorithm, a support vector regression algorithm, a K nearest neighbor (KNN) regression algorithm, and a design of experiment (DOE) algorithm. [0100] The database 360 may transmit the correlation model between the DC pulse power and the electron density to the controller 340 . The controller 340 may control the DC pulse power, which is supplied to the sidewall electrode 116 by the DC pulse power supplier 330 , based on the correlation model between the DC pulse power and the electron density. [0101] By controlling the DC pulse power, which is supplied to the sidewall electrode 116 by the DC pulse power supplier 330 , based on the correlation model between the DC pulse power and the electron density, the electron density in the central area (C area) and the electron density in the outside area (E area) may be controlled. [0102] FIG. 7 is a configuration diagram of a plasma generation apparatus 400 according to another exemplary embodiment. [0103] Referring to FIG. 7 , the plasma generation apparatus 400 may include a chamber 410 , first and second RF pulse power suppliers 420 _ 1 and 420 _ 2 , a DC pulse power supplier 430 , and a controller 440 . [0104] The chamber 410 may include a lower electrode 412 , an upper electrode structure 414 , a plurality of sidewall electrodes 416 , and a gas-discharging unit 418 . [0105] The upper electrode structure 414 may include a gas-supplying unit 414 a, a nozzle 414 b, and an upper electrode 414 c. In some embodiments, the gas-supplying unit 414 a may be disposed in the upper electrode structure 414 , as shown in FIG. 7 . However, the inventive concept is not limited thereto. For example, the gas-supplying unit 414 a may be disposed outside the chamber 410 , independent of the upper electrode structure 414 . [0106] The gas-supplying unit 414 a may supply a reaction gas to the chamber 410 via the nozzle 414 b, and a gas may be exhausted via the gas-discharging unit 418 to maintain the chamber 410 in a vacuum state. [0107] The first RF pulse power supplier 420 _ 1 for applying a first RF pulse power to the upper electrode 414 c may be connected to the upper electrode 414 c. [0108] In some embodiments, the first RF pulse power supplier 420 _ 1 may include a first RF power generator 422 _ 1 and a first matching unit 424 _ 1 . [0109] In some exemplary embodiments, an RF power generated by the first RF power generator 422 _ 1 and a pulse signal output from the controller 440 may be mixed in the first matching unit 424 _ 1 to generate a pulse-modulated RF pulse power. [0110] The first RF pulse power that is supplied by the first RF pulse power supplier 420 _ 1 may be, for example, a source power. [0111] In some exemplary embodiments, the first RF pulse power may be, for example, a high frequency (HF) pulse in a frequency range that is equal to or greater than about 13.56 MHz and is less than about 60 MHz or a very high frequency (VHF) pulse in a frequency range that is equal to or greater than about 60 MHz and is less that about several hundred MHz. [0112] In some other embodiments, the first RF pulse power may be an RF pulse obtained by mixing multiple frequencies. For example, the first RF pulse power may be variously changed by mixing the VHF pulse and the HF pulse. [0113] The lower electrode 412 may function as a wafer chuck. In some embodiments, the lower electrode 412 may be an ESC that adsorbs and supports a wafer by an electrostatic force. In some other embodiments, the lower electrode 412 may be a mechanical clamping type chuck or a vacuum chuck that adsorbs and supports a wafer by vacuum pressure. [0114] In some exemplary embodiments, a second RF pulse power supplier 420 _ 2 may be connected to the lower electrode 412 . The second RF pulse power supplier 420 _ 2 may include a second RF power generator 422 _ 2 and a second matching unit 424 _ 2 . [0115] In some exemplary embodiments, an RF power generated by the second RF power generator 422 _ 2 and a pulse signal output from the controller 440 may be mixed in the second matching unit 424 _ 2 to generate a pulse-modulated RF pulse power. [0116] The second RF pulse power that is supplied by the second RF pulse power supplier 420 _ 1 may be a bias power. [0117] The second RF pulse power supplier 420 _ 2 may supply the second RF pulse power in a frequency that is lower than that of the first RF pulse power that is supplied by the first RF pulse power supplier 420 _ 1 . For example, the second RF pulse power may be a low frequency (LF) pulse in a frequency range that is equal to or greater than about 0.1 MHz and is less than about 13.56 MHz. [0118] The plasma generation apparatus 400 may use a CCP method. Specifically, when the first RF pulse power is supplied to the upper electrode 414 c and the second RF pulse power is supplied to the lower electrode 412 , an electric field may be induced between the upper electrode 414 c and the lower electrode 412 . At this time, when a reaction gas is injected in the chamber 410 via the gas-supplying unit 414 a installed in the top of the chamber 410 , the reaction gas may be changed to a plasma state due to an electric field induced inside the chamber 410 . A wafer processing process, such as an etching or thin film deposition process for a wafer W, may be performed by using the generated plasma. [0119] In some exemplary embodiments, the first RF pulse power that is supplied to the upper electrode 414 c may perform a function of igniting plasma, and the second RF pulse power that is supplied to the lower electrode 412 may perform a function of controlling plasma. [0120] The plurality of sidewall electrodes 416 may be arranged at sidewalls of the chamber 410 . The DC pulse power supplier 430 , which supplies a DC pulse power for adjusting the density of electrons or positive ions of etching gases in the chamber 410 , may be connected to the sidewall electrodes 416 . [0121] The controller 440 may control the first and second RF pulse power suppliers 420 _ 1 and 420 _ 2 and the DC pulse power supplier 430 . [0122] In some exemplary embodiments, RF powers generated by the first and second RF power generators 422 _ 1 and 422 _ 2 and a DC power generated in the DC pulse power supplier 430 may be pulse-modulated by the control of the controller 440 . In addition, first and second RF pulse powers that are supplied by the first and second RF pulse power suppliers 420 _ 1 and 420 _ 2 and a DC pulse power that is supplied by the DC pulse power supplier 430 may be synchronized by the control of the controller 440 . [0123] FIG. 8 is a configuration diagram of a plasma generation apparatus 500 according to another exemplary embodiment. [0124] Referring to FIG. 8 , the plasma generation apparatus 500 may include a chamber 510 , first and second RF pulse power suppliers 420 _ 1 and 420 _ 2 , a DC pulse power supplier 430 , and a controller 440 . [0125] The chamber 510 may include a lower electrode 412 , an upper electrode structure 514 , a plurality of sidewall electrodes 416 , and a gas-discharging unit 418 . [0126] The upper electrode structure 514 may include a gas-supplying unit 514 a, a nozzle 514 b, an insulating plate 514 c, and an antenna 514 d. In some embodiments, the gas-supplying unit 514 a may be disposed in the upper electrode structure 514 , as shown in FIG. 8 . However, the inventive concept is not limited thereto. For example, the gas-supplying unit 514 a may be disposed outside the chamber 510 , independent of the upper electrode structure 514 . [0127] The gas-supplying unit 514 a may supply a reaction gas to the chamber 510 via the nozzle 514 b, and a gas may be exhausted via the gas-discharging unit 518 to maintain the chamber 510 in a vacuum state. [0128] The plasma generation apparatus 500 may use an ICP method. Specifically, after the chamber 510 is exhausted by the gas-discharging unit 518 , a reaction gas for generating plasma is supplied from the gas-supplying unit 514 a to the chamber 510 . Furthermore, a first RF pulse power from the first RF pulse power supplier 420 _ 1 is applied to the antenna 514 a. As the first RP pulse power is applied to the antenna 514 d, lines of magnetic force may be formed around the antenna 514 d. An induced electric field may be formed inside the chamber 510 due to the lines of magnetic force, and the induced electric field may heat electrons to generate ICP. [0129] In some exemplary embodiments, the insulating plate 514 c may be disposed between the antenna 514 d and the lower electrode 412 . The insulating plate 514 c may facilitate transmission of energy supplied from the first RF pulse power supplier 420 _ 1 to plasma by an inductive coupling by reducing a capacitive coupling between the antenna 514 d and the plasma. [0130] The antenna 514 d may have one or more spiral coil shapes as seen in a plan view. However, the inventive concept is not limited thereto. For example, the antenna 514 d may have various shapes other than the spiral coil shape. [0131] FIGS. 9A through 9C are timing diagrams illustrating operations of first and second RF pulse powers and an operation of a DC pulse power according to exemplary embodiments. [0132] Some elements of the plasma generation apparatus 400 shown in FIG. 7 may be referred to in descriptions referred to FIGS. 9A through 9C . [0133] Referring to FIG. 9A , a first RF pulse power RFPP 1 may be supplied from the first RF pulse power supplier 420 _ 1 to the upper electrode 414 c, a second RF pulse power RFPP 2 may be supplied from the second RF pulse power supplier 420 _ 2 to the lower electrode 412 , and a DC pulse power DCPP 7 may be supplied from the DC pulse power supplier 430 to the sidewall electrodes 416 . [0134] The first RF pulse power RFPP 1 and the second RF pulse power RFPP 2 may be synchronized with each other. In some embodiments, the first RF pulse power RFPP 1 and the second RF pulse power RFPP 2 may be simultaneously pulsed on and pulsed off without having a phase difference. Accordingly, the on-time RF 1 _To and the off-time RF 1 _Tf of the first RF pulse power RFPP 1 may be substantially the same as the on-time RF 2 _To and the off-time RF 2 _Tf of the second RF pulse power RFPP 2 , respectively. [0135] The DC pulse power DCPP 7 may be synchronous with the first RF pulse power RFPP 1 and the second RF pulse power RFPP 2 . [0136] For example, as shown in FIG. 9A , the DC pulse power DCPP 1 may be pulsed off during the on-times RF 1 _To and RF 2 _To of the first and second RF pulse powers RFPP 1 and RFPP 2 , and may be pulsed on during the off-times RF 1 _Tf and RF 2 _Tf of the first and second RF pulse powers RFPP 1 and RFPP 2 . In other words, the on-time DC 7 _To of the DC pulse power DCPP 7 may be substantially the same as the off-times RF 1 _Tf and RF 2 _Tf of the first and second RF pulse powers RFPP 1 and RFPP 2 , and the off-time DC 7 _Tf of the DC pulse power DCPP 7 may be substantially the same as the on-times RF 1 _To and RF 2 _To of the first and second RF pulse powers RFPP 1 and RFPP 2 . [0137] Referring to FIG. 9B , a first RF pulse power RFPP 1 may be supplied from the first RF pulse power supplier 420 _ 1 to the upper electrode 414 c, a second RF pulse power RFPP 2 may be supplied form the second RF pulse power supplier 420 _ 2 to the lower electrode 412 , and a DC pulse power DCPP 8 may be supplied from the DC pulse power supplier 430 to the sidewall electrodes 416 . [0138] The first RF pulse power RFPP 1 and the second RF pulse power RFPP 2 may be synchronized with each other, but may be supplied with having a phase difference. In other words, the second RF pulse power RFPP 2 may be shifted by a delay time td 5 compared to the first RF pulse power RFPP 1 . Specifically, the second RF pulse power RFPP 2 may not be pulsed off directly after the first RF pulse power RFPP 1 enters into the off-time RF_Tf from the on-time RF_To, but may be pulsed off after a lapse of a delay time td 5 . In addition, the second RF pulse power RFPP 2 may not be pulsed on directly after the first RF pulse power RFPP 1 enters into the on-time RF_To from the off-time RF_Tf, but may be pulsed on after a lapse of a delay time td 6 . [0139] In some embodiments, as shown in FIG. 9B , the DC pulse power DCPP 8 may be pulsed on when both the first RF pulse powers RFPP 1 and the second RF pulse power RFPP 2 are pulsed off, that is, only in a period in which the off-time RF 1 _Tf of the first RF pulse powers RFPP 1 and the off-time RF 2 _Tf of the second RF pulse power RFPP 2 overlap each other. [0140] In this case, the on-time DC 8 _To of the DC pulse power DCPP 8 may be shorter than the off-time RF 1 _f of the first RF pulse power RFPP 1 or the off-time RF 2 _Tf of the second RF pulses power RFPP 2 , and the off-time DC 8 _Tf of the DC pulse power DCPP 8 may be longer than the on-time RF 1 _To of the first RF pulse power RFPP 1 or the on-time RF 2 _To of the second RF pulses power RFPP 2 . [0141] Referring to FIG. 9C , a first RF pulse power RFPP 1 may be supplied from the first RF pulse power supplier 420 _ 1 to the upper electrode 414 c, a second RF pulse power RFPP 2 may be supplied form the second RF pulse power supplier 420 _ 2 to the lower electrode 412 , and a DC pulse power DCPP 9 may be supplied from the DC pulse power supplier 430 to the sidewall electrodes 416 . [0142] As described with reference with FIG. 9B , the second RF pulse power RFPP 2 may be shifted by a delay time td 5 compared to the first RF pulse power RFPP 1 . [0143] In some embodiments, the DC pulse power DCPP 9 may be pulsed on during the off-time of one selected from the first and second RF pulse powers RFPP 1 and RFPP 2 . For example, the DC pulse power DCPP 9 may be pulsed on during the off-time RF 1 _Tf of the first RF pulse power RFPP 1 . [0144] In this case, the on-time DC 9 _To of the DC pulse power DCPP 9 may be substantially equal to the off-time RF 1 _Tf of the first RF pulse power RFPP 1 , and the off-time DC 9 _Tf of the DC pulse power DCPP 9 may be substantially equal to the on-time RF 1 _To of the first RF pulse power RFPP 1 . [0145] While the inventive concept has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood that various changes in form and details may be made therein without departing from the spirit and scope of the following claims.

A plasma generation apparatus is provided. The plasma generation apparatus includes a chamber defining a reaction space that can be isolated from an external environment, an upper electrode provided in an upper portion of the chamber, a lower electrode provided in a lower portion of the chamber, a sidewall electrode provided at a sidewall of the chamber, a radio frequency (RF) pulse power supplier configured to supply RF pulse power to at least one selected from the upper electrode and the lower electrode, and a direct current (DC) pulse power supplier configured to supply DC pulse power to the sidewall electrode.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to image processing and, more specifically, to automated digital image processors useful for the identification of dividing cells for the examination of various biological cellular events. 2. Prior Art Much of the experimental work in the field of cell and molecular biology of cultured cells involves the assay of the proliferative activity of these cells. This is especially true for problems in biological time, rhythmicity and time sense which require for their resolution continuous surveillance and frequent data acquisition. Critical to such work is an accurate count of incidents of mitosis, or cell division, in a cell culture. Incidents of mitosis are easily identified because mitotic cells in culture tend to round up and become refractile and annular in appearance under phase contrast illumination. Thus it is possible for a human observer to count incidents of mitosis by observing the cell culture under such illumination. Up to the present time, all of this information has been collected by researchers by hand without the extensive use of computers. This is a particular problem because the need for extensive observation of the growth of cells in such cultures makes human observation an inconveniently long and tedious process in a laboratory setting. In addition, such observation requires a high degree of accuracy, and consequently several observers must be used to insure such accuracy. One present method for performing such experiments is to place a plated culture of cells under a microscope under phase contrast illumination, and to record the microscopic images over time using a video tape recorder having time lapse videophotography capability. The time at which each cell divided, or more typically, elapsed time from a predetermined event can be determined from the videotapes. This information has been provided by a digital clock which generates a time signal that is superimposed on the viewing video screen. Thus, the number of cells dividing during the experiment, and the time at which each division occured can be obtained. A 48:1 time compression is generally used so that a 48 hour recorded observation can be viewed in one hour. Of course, since multiple events may occur on the screen at the same time, an observer may be required to review the tape a multiple number of times to observe all mitotic events. Thus, the review of a 48 hour tape may easily take eight hours or longer for a skilled human observer to complete. What is required is an automated means for recording these incidents of mitosis which is rapid, automated, and non-perturbing. This last criteria is particularly important in research involving rhythmicity and time sense. As disclosed below, the present invention provides such a means. Such an automated system permits continual observation of cell cultures over extended periods of time that was not available under the manual methods of the prior art. The use of such automated system would make such data handling and analysis faster and significantly more accurate, and further would enable the researchers to derive additional information from such experiments which have heretofore been very difficult to obtain on a large population of cells, because of the difficulty in tracking individual cells and their progeny on a large scale. SUMMARY OF THE INVENTION The present invention provides methods and apparatus which are used in conjunction with a digital computer system to identify and record events in a binary representation of a visual image. Specifically, algorithm means are provided whereby incidents of mitosis in a cell culture can be identified by image analysis techniques. Images are obtained using a video camera in combination with a microscope and low intensity phase contrast illumination to observe a cell culture. The signal from the video camera is then periodically sampled. The sampled signal is then digitized and the relevant detail extracted. The phase contrast halo which surrounds potentially mitotic cells is recognized using a series of transformations of the digitized image. The temporal and spatial relationships of the cell groupings from successive images are then analyzed to determine if mitosis has in fact occurred, and if so this fact is recorded. By utilizing a series of transformations to identify the halo surrounding the mitotic cells, only the digital image information in the region immediately surrounding the specific cells is analyzed. In addition, the coordinates of each ringed (mitotic) cell identified, along with other relevant information, is recorded in a list in memory as each image frame is processed. In this way, detection of mitosis between pairs of cells which appear at different times is facilitated because the entire digital image from each frame does not need to be compared with all the others at the end of the observation period. All that is required is cross-comparison of the information stored in the list in memory to identify mitotic cell pairs. The preferred embodiment of the present invention provides a means for electronically viewing an image, most advantageously a microscope fitted with a standard newvicon video camera. Also provided is a digital image processor for conversion of the video signal to digital information. This processor is most advantageously coupled to a general purpose digital computer. The digital computer performs the analysis of the digital image produced by the image processor. Algorithm means are provided both to transform the digital image (or portions thereof) within the processor memory and to detect an actual event of mitosis. Detected incidences of mitosis are recorded in computer mass storage memory for later display on a standard device, such as a cathode ray tube (CRT) or printer. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of the present invention. FIG. 2 is a block diagram of a digital image processor used in the present invention. FIG. 3a illustrates a typical arrangement of the memory in the internal RAM of the host computer in the present invention. FIG. 3b illustrates a typical arrangement of a segment of the memory in the digital image processor of the present invention. FIG. 4 illustrates the four structuring elements used to make a grey image ridge extraction as contemplated for the present invention. FIG. 5 illustrates a two-dimensional thin-ring-shaped structuring element used in the RT-transformation. FIG. 6 illustrates the data structure for application of decision rules for mitotic events. FIG. 7 illustrates the dilation of an image by a structuring element. DETAILED DESCRIPTION Notation and Nomenclature The detailed descriptions which follow are presented largely in terms of algorithms and symbolic representations of operations on data bits within a computer memory. An algorithm is here, and generally, conceived to be a self-consistent sequence of steps leading to a desired result. These steps are those requiring physical manipulations of physical quantities. Usually, though not necessarily, these quantities take the form of electrical or magnetic signals capable of being stored, transferred, combined, compared, and otherwise manipulated. It proves convenient at times, principally for reasons of common usage, to refer to these signals as bits, values, elements, symbols, characters, terms, numbers, or the like. It should be borne in mind, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. Further, the manipulations performed are often referred to in terms, such as adding or comparing, which are commonly associated with mental operations performed by a human operator. No such capability of a human operator is necessary, or desirable in most cases, in any of the operations described herein which form part of the present invention; the operations are machine operations. Useful machines for performing the operations of the present invention include general purpose digital computers or other similar devices. In all cases there should be borne in mind the distinction between the method operations in operating a computer and the method of computation itself. The present invention relates to method steps for operating a computer in processing electrical or other (e.g., mechanical, chemical) physical signals to generate other desired physical signals. The present invention also relates to apparatus for performing these operations. This apparatus may be specially constructed for the required purposes or it may comprise a general purpose computer as selectively activated or reconfigured by a computer program stored in the computer. The algorithms presented herein are not inherently related to any particular computer or other apparatus. In particular, various general purpose machines may be used with programs written in accordance with the teachings herein, or it may prove more convenient to construct more specialized apparatus to perform the required method steps. The required structure for a variety of these machines will appear from the description given below. The specific algorithms described below are most conveniently expressed using the formal notation of morphology, a mathematical analysis which embodies sets in digital space. This formalism provides a concise mode of presentation by repeated reference to a physical model of a digital image composed of stacks of boxels (cubes). A two dimensional picture represented by a rectangular array of pixels, each with a distinct gray value, would thus be modelled by a three dimensional solid where, at each Cartesian x,y-coordinate there is a stack of boxels (stacked in the Cartesian z-direction), the height of which corresponds to the gray value of the picture (0-255) at that coordinate. In the following dictionary of terms, X and Y refer to sets and x and y to boxels. When Cartesian directions are meant, they will be explicitly so labelled. Image analysis amounts to set transformations, where the elements of the sets are the discrete image boxels. A more detailed description of the notation of morphology can be found in the comprehensive text by J. Serra, Image Analysis and Mathematical Morphology, London, Academic Press, Inc., 1982. For the purpose of understanding the present invention, the following notations will be used, which notations have the respective meanings set forth below. x a boxel X a set of boxels x X set membership; boxel x belongs to set X X Y set X is included in set Y X∩Y set intersection; set of boxels belonging to both set X and set Y f numerical function defining the gray value at each Cartesian x,y coordinate of the picture; they may be thought of as a three dimensional surface defining the upper contours of the three dimensional boxel model. X t (f)the family of two dimensional sets, called sections, composed of the boxels present at height t, for 0≦t≦255. The family of such sets taken as a whole comprises the umbra of the function and generates the function. X⊕B dilation of set X by structuring element B (also a set). For a two dimensional set, for example: translate B to every image point in turn. If any element of B hits (touches, overlays) any element of X then mark the hit at the image point corresponding to the current position of the origin of the structuring element. The set of such marks represents the dilated set. For example, ##EQU1## For a three dimensional set such as the umbra of a function f, dilation by a two dimensional structuring element, in principle, is accomplished by applying the two dimensional dilation to each X t in the family of X t 's, 0≦t≦255 for the function f. The result is a new family of sets, X t (f⊕B), which are the sections of the function (the picture) dilated by the two-dimensional structuring element B. In practice, the dilation for a picture is accomplished by first considering the surface defined by the topmost boxels (the function f) to be an impenetrable barrier. The structuring element then roams about above the surface: at each image Cartesian x,y coordinate the structuring element is lowered until it first hits the surface at any boxel; the height of the origin of the structuring element is noted at that particular Cartesian x,y coordinate; the picture thus calculated is the dilated picture. The manner of computing this is straightforward. Each pixel in a picture is replaced by the maximum gray value found at relative positions in its immediate neighborhood which correspond to similar relative positions of the structuring element. f-g difference to two functions; the resulting function is a picture (no negative gray values) if and only if X t (g) X t (f), where 0≦t≦255 (i.e., g≦f at every Cartesian x,y coordinate). X t (f)∩X t (g) intersection of the sections of two pictures; this is computed by taking the minimum value, pixel-by-pixel in comparing pictures f and t. The sections of the resulting picture will be the desired set intersection. The following description is divided into several sections. The first of these will discuss the general configuration of a system for processing digital images. Later sections will address specific aspects of the present invention, such as extraction of the relevant detail, identification of the phase contrast halo by image transformations, and analysis of the relationships between identified cells to detect mitosis. GENERAL SYSTEM CONFIGURATION FIG. 1 shows a typical computer-based system for image processing according to the present invention. Conversion of optical images to electronic signals is accomplished by the combination of a standard newvicon video camera 23 and a microscope 20 utilizing low intensity phase contrast illumination. This video camera and microscope are representative of generally available video and optical equipment for scientific use. In the system utilized by the inventors, the camera and microscope optics together result in a 600× magnification. Of course, it will be generally recognized that the magnification is a function of the type, and particularly the size of the cells used. In the present embodiment, the microscope and camera combination are used to observe mitosis in cell culture 24. The video signal generated by camera 23 is coupled to digital image processor 27, shown in detail in FIG. 2. This image processor contains several internal elements for processing the incoming video signal and converting said signal to digital form. These elements include an internal processor (CPU) 40, capable of controlling all the internal components of the image processor, accepting commands from an external host computer, and transmitting a video signal, in digital form, to such host computer. An internal program memory 42 is included for storage of instructions and routines received from the host computer. The image processor also contains two look-up tables 45, two digital-to-analog converters 46, one 8 bit (256 possible gray levels) analog-to-digital converter 47, a binary shifter 49 and an image statistics unit 44. Also shown are two 8-bit random access memories (RAMs) 41, and a 16-bit RAM 43. These RAM memories are used to store both raw (unprocessed) and processed digital image data, as well as other data derived during the analysis of the images. FIG. 3b shows a typical arrangement of 8-bit RAMs 41, including an Image Pixel Array 52 and a Degree of Closure Array 45, both used in processing the image as described in more detail below, space for the raw image data 57 and space for other data and spare memory 59. The image processor shown is intended to be representative of the general class of devices for processing such signals under host computer control. A particular example of a suitable image processor is the EyeCom III model image processor manufactured by DBA (from Florida). Other image processors having similar capabilities are easily adapted for use in the present invention. Digital information representing the processed video signal is transferred from the image processor to host computer 39 via direct memory access channel 30 (the "DMA"). These two elements are typically found in most general purpose computer systems and in many specialized computer systems. Any of numerous, easily available, data processors which provide for DMA are readily adaptable to use as shown. Also shown in FIG. 1 is a mass storage device 34 connected to host computer 39. This mass storage device may be any of a number of available devices, including magnetic tape, magnetic disk, paper tape or cards. The data retained in mass storage 34 may be transferred to and from host computer 39. Such mass storage is used to augment the internal memory of host computer 39 and to provide for permanent storage of data. A CRT terminal 37 is also shown coupled to host computer 39. This terminal is used to permit an operator to enter commands and to allow data collected by host computer 39 to be displayed. It should be noted that any device capable of exchanging character level data with the host computer may be used in place of the CRT terminal 37, including a printer or another computer. Host computer 39 contains an internal RAM memory 51 to store programs and data, as shown in FIG. 3a. The typical arrangement of the major portions of memory 51 are also shown in FIG. 3a. Space is provided for programs 50 which represent a variety of sequences of instructions for execution by the host computer, including instructions for implementing the operations and routines described herein, monitor and control programs, disk operating systems and the like. Memory space is also reserved for a Temporal Vicinity List ("TV-list"), which contains the subset of image data necessary to detect incidents of mitosis, in TV-list space 56. Additionally, space within memory 51 is reserved for other programs and spare memory as designated at 58. These other programs may include a variety of useful computational or utility programs as desired. DIGITIZATION AND DETAIL EXTRACTION The combination of microscope 20, camera 23 and image processor 27, shown in FIG. 1, provides a digital representation of the image consisting of 640×480 picture element (pixel) frames. Each pixel in a frame contains a value corresponding to the gray level detected by the camera at that point. In the typical embodiment of the present invention shown, 256 possible gray levels, ranging from white to black, are available. In the preferred embodiment of the present invention, the camera and microscope optics together provide a resolution of 0.9 micron/pixel. Image operations on the frames occur at the standard video rate of 30 frames/second. The present invention achieves real time image analysis by sampling and digitizing the live video input from the cell culture once each minute. Thirty-two successive video frames are sampled, averaged and the result is stored in 8-bit RAMs 41 (FIG. 3b) contained in image processor 27 (FIG. 1). Transformation and analysis of this stored image is accomplished, as described below, by image processor 27 under instructions from host computer 39 transferred via DMA 30 (FIG. 1). The desired image features, specifically the phase contrast halos surrounding potentially mitotic cells, are extracted by subtracting a transformed image, "g", from the original image, "f". This transformation is accomplished by successivly dilating the original image f (treated as a two-dimensional set) by a structuring element, "B". To perform the dilation, a series of four structuring elements, B0-B3, are used as shown in FIG. 4. The effect of gray image dilation can be visualized by taking the gray values to define elevation of a terrain in the Cartesion z direction, if one considers the image plane to lie in the Cartesian xy plane. Over each pixel, the origin of the structuring element is centered and the structuring element is then lowered, without tilting, until it first contacts the terrain. The elevation of the origin of the structuring element at that first contact is taken to be the gray value at that pixel in the dilated result. This process for a one-dimensional image using a one-dimensional structuring element without holes can be seen by viewing such an image in profile in FIG. 7a. Dilation results in a picture with gray values at every pixel either greater than or equal to the corresponding gray value in the original picture. Compare the dilation in FIG. 7a with the result obtained by using a structuring element containing a hole, FIG. 7b. It can be seen from FIG. 7b that peaks in the original profile are distinguished as being those regions where pixel gray values decrease (shaded regions) rather than increase upon dilation. In other words, a place in the image where the structuring element can be lowered to first contact and consequently straddle a piece of the image with a higher elevation is a peak in the image. Returning to a discussion of two-dimensional images: image features such as ridges and peaks would be lowered upon dilation by one or more of the structuring elements B N . Different orientations of the structuring element B N are required to sense ridges oriented at different angles in the xy image plane. At each pixel the minimum value for each of four dilations, using these structuring elements is recorded, i.e. the result of the intersection taken over the variable N in the following equation: ##EQU2## The intersection of the umbra of the new image with that of the original is computed in order to assure that X t (g)≦X t (f). The number of pixels in the interval between the two elements of each B N , is determined by the two-dimensional thickness of the phase contrast detail of interest. The transformed image g subtracted from the original image f produces a ridge-extracted picture. This new image provides greater clarity by displaying only the objects of interest from the original image, in the present embodiment the phase contrast halos around cells. The ridge-extracted picture produced above is then converted to a binary picture using a technique known as "threshold comparison". This technique involves comparing the gray level representation for each pixel with a selected threshold value. For each pixel with a value less than the threshold value, the gray level value for that pixel is replaced with the value zero. For each pixel with a gray level value greater than or equal to the threshold value, the value for that pixel is replaced with a fixed, nonzero value. In the preferred embodiment of the present invention, a threshold gray level value of seven is used, and a value of 128 is chosen to replace the value for all pixels greater than or equal to the threshold. The result of this threshold comparison technique is to increase the detail and clarity of the image. RING SHAPE RECOGNITION The present invention provides for analysis of the image which has been transformed and undergone threshold comparison described above utilizing instructions from host computer 39 transferred to image processor 27 via DMA 30 (FIG. 1). A cyclic series of transformations is performed on the image in order to detect the presence of annular objects corresponding to the phase contrast halos of the mitotic cells. Each of the transformations performed probes for a thin annulus of specific radius. In the preferred embodiment of the present invention, the radii probed range from five to ten pixels. Each transformation in the series consists of two steps, annulus transformation (A-transformation) followed by ring-toss transformation (RT-transformation), described as follows. In the A-transformation, to probe for an annulus of radius "r", a one-pixel wide annular mask of such radius is centered at each pixel. The degree of concidence of the mask with white objects in the image (gray value 128) is computed by summing the pixels covered by the mask, and dividing by the number of pixels in the mask. This value is then stored at the location of the central pixel for the ring in 8-bit RAM 41 (FIG. 3b). In the A-transformed image, objects which originally approximated annuli of radius r appear as locally bright spots having a brightness which indicates a degree of ring closure. The A-transformation may be expressed as follows: ##EQU3## where the h i represent all discrete orientations of a translation vector of length r radiating from a common point (hence described as a one-pixel-wide annulus) and p represents the finite number of such vectors. Such A-transformation is carried out once for each radius probed. In the preferred embodiment this ranges from five to ten pixels, requiring six A-transformations. Each A-transformed image is used to update the Degree of Closure Array 54. Updating is performed using a MAXIMUM operation, where pixels in the A-transformed image are compared with elements stored in the Degree of Closure Array 54. If the value stored at a given pixel in the A-transformed image is greater than the value stored in the Degree of Closure Array, the value in the array is replaced by the larger value. This operation results in each element in Degree of Closure Array 54 containing a value representing the Degree of Ring Closure for annuli surrounding the object centered at the pixel with corresponding coordinates in 8-bit RAM memory 41 (FIG. 3b). Information stored in this fashion is utilized for subsequent data interpretation, as described in the next section. Following each A-transformation, an RT-transformation is performed to extract the local maxima in the A-transformed image. This RT-transformation involves subtracting from the A-transformed image an image calculated by dilating the A-transformed image by a two-dimensional thin-ring-shaped structuring element, B R =8, shown in FIG. 5. The appropriate radius of the ring is dependent upon the thickness of the rings themselves in the original picture. In the preferred embodiment, a radius of eight pixels has proved to be effective. After this subtraction is performed, only pixels contained by the B R =8 structuring element remain. The RT-transformation is expressed as follows: f.sub.RT (x) =f.sub.A (x) -g(x) where g(x) is given by: X.sub.t (g) =X.sub.t (f.sub.A) ∩X.sub.t (f.sub.A ⊕B.sub.R =8) The image resulting from this RT-transformation is then subjected to threshold comparison, according to the above described method to isolate significant maxima remaining after the RT-transformation. In the preferred embodiment, this threshold comparison is performed using a threshold value of gray level 50. Upon completion of each cycle of A-transformation followed by RT-transformation and threshold comparison, the resulting binary image is used to update Image Pixel Array 52 using a bit-by-bit logical OR operation. Upon completion of the series of transformations for all desired radii, the binary image of significant maxima, stored in Image Pixel Array 52 is thinned to isolated pixels using a fourpass algorithm based on connectivity number as described in Yokoi, S., Toriwaki, J-I, Fukumara, T.; "An analysis of topological properties of digitized binary pictures using local features", Computer Graphics and Image Processing 4: 63-73, 1975: The coordinates of the residual bits remaining in Image Pixel Array 52 (FIG. 3b) after thinning are determined and passed to the host computer program 50, along with the degree of ring closure corresponding to each such residual stored in the Degree of Closure Array 54. These data together with the actual time (wall clock time) are then recorded on mass storage device 34, and, in addition, analyzed for spatial and temporal relationships to discern mitotic events as described below. DETERMINING MITOTIC EVENTS In order to detect a mitosis, it is necessary that both daughter cells be detected, though not necessarily in the same video frame. A time invariant handicap to this end is that mitotic cells tend to lie in a slightly different focal plane than nonmitotic cells. This is easily corrected by offsetting the focal adjustment of the microscope. Not all mitotic cells, however, are clearly in focus due to their tendency to float, and hence some daughters are overlooked on this basis. Moreover, aggregates of cells pose the problem that the phase contrast halo around each cell becomes discontinuous at the points of contact with other cells. Some allowance is made for this fact, at the expense of accepting some artifacts. The number of artifacts and oversights per frame roughly increase with the degree of cellular confluency. Artifacts can be eliminated to some degree at the level of the decision rules whereby temporal and spatial relationships are discerned. An artifact really only poses a problem when it appears in the vicinity of true mitotic cells, or another artifact, where it might be mistaken for a daughter cell, and falsely imply a mitotic event. The decision rules are limited in their success by the success of the image analysis algorithms in recognizing all the relevant annular objects in the processed pictures. The rules must make sense out of the motion picture of constellations with which they are presented. As one skilled in the art will appreciate, it is difficult to account for all possible orientations of putative mitotic cells on a background of false positives, and hence a sufficiently general set of rules which will produce results which preserve the essence of the proliferative behavior of the population have been developed. The above described image analysis procedures produce raw data in the form of image coordinates and the degree of ring closure for annuli in each video frame sampled. Such raw data is both stored permanently on mass storage device 34 for later reference and interpreted by analyzing temporal and spatial relationships between annular objects to detect a pair of annular objects representing a pair of cells undergoing mitosis. In discerning these relationships, only a subset of the data need be considered, specifically the data for those annuli detected in the temporal vicinity of the current video frame being analyzed. This subset of data is retained in the host computer memory 51 (FIG. 3a) in a list data structure using a dynamic array as shown in FIG. 6. Each node in this Temporal Vicinity List (TV-list) 60 consists of the of the following data items: X, Y picture coordinates of annulus center R degree of ring closure TB time this annular object first noted TE time this annular object last noted P index of partner if this annular object is paired with another FA flag: indicates whether node is currently active; once the record of an annular object ages sufficiently it is deactivated and its node is freed for re-use. FQ flag: indicates whether node is qualified for consideration as a partner to another annular object. TV-list space 56 (FIG. 3a) is reserved for this TV-list 60 in an amount sufficient to accomodate N data nodes. In the presently preferred embodiment N is set at 180 to accomodate interpreting up to 180 active annular objects at any time, though N may be adjusted upward or downward as desired or limited, of course, by available memory space in the host computer. A top-of-list pointer 61 (FIG. 6) is maintained to facilitate searching the TV-list in which deactivated, or freed, nodes may be re-used. Upon obtaining the image coordinates and Degree of Ring Closure of annular objects in the current video frame, the following steps are executed. First the TV-list 60 is updated. For each annular object detected in the current video frame a search is conducted for an annular object entry in the TV-list 60 whose coordinates are within seven pixels distance. If none is found the new annular object is added to the TV-list. If such an annular object entry is found, then the X,Y,R, and TE fields of that entry are updated to reflect the new object. Second, the TV-list is scanned to retire nodes which have aged sufficiently. In the presently preferred embodiment nodes for those objects detected more than 15 minutes prior to the current video frame are retired. If two annular objects have been paired (representing a possible daughter pair resulting from an incident of mitosis) then both nodes must meet the age criterion noted above before either can be retired. At such a time, the pair is considered a definite indication of a mitotic event and the event is taken to have occurred at a time corresponding to the greater (later) TB of the two annular objects involved. Retirement of an annular object node amounts to recording the data from that node on mass storage 34 and then clearing the FA flag. Finally, active annular objects from the TV-list are paired to discern possible daughter cell pairs indicating a mitotic event. Annular objects within 20 pixels of each other are considered. In the event that more than two annular objects clustered together, pairs are formed between the nearest annular objects. Before two annular objects can be paired by spatial proximity, both must meet a criterion of minimum degree of ring closure else the pairing is disqualified from ever being considered. Any pairing is considered tentative until such a time as both members are considered eligible for retirement. Until that time, pairing may be revised upon detection of new annular objects in the neighborhood of existing ones. A record of mitotic events is stored permanently on mass storage device 34. Upon completion of the analysis of the entire set of frames, the mitotic activity is summarized by plotting a histogram of the events employing a user-selected bin size. Such plot is displayed on CRT 37 in the preferred embodiment. It is important to note that all disclosed parameters relating to spatial and temporal relationships between annular objects are completely adjustable. These parameters may be set, as desired, to provide accurate monitoring of types of activity other than incidents of mitosis. By adjusting these parameters the present invention may be applied to monitoring various events, both biological and otherwise, observable via video camera 23 (FIG. 1). CODING DETAILS No particular programming language has been indicated for carrying out the various procedures described above. This is in part due to the fact that not all languages that might be mentioned are universally available. Each user of a particular computer and image processor will be aware of the language which is most suitable for his immediate purposes. In practice, it has proven useful to substantially implement the present invention in ANSI-77 standard Fortran. Because the computers and image processing systems which may be used in practicing the instant invention consist of many diverse elements and devices, no detailed program listings have been provided. It is considered that the operations and other procedures described above and illustrated in the accompanying drawings are sufficiently disclosed to permit one of ordinary skill in the art to practice the instant invention or so much of it as is of use to him. Thus, methods and apparatus which are most advantageously used in conjunction with a digital computer and image processor to provide automated recording and analysis of cell mitosis and other cellular events have been disclosed. The present invention's use of A-transformations, RT-transformations, threshold comparison, and the above-mentioned decision criteria permit automation of a task which could only be accomplished manually under the prior art. While the present invention has been particularly described with reference to FIGS. 1-6 and with emphasis on certain computer systems and image processing systems, it should be understood that the figures are for illustration only and should not be taken as limitations upon the invention. In addition, it is clear that the methods and apparatus of the present invention have utility in any application where automatic recording of various cellular or other similar events is desired. It is contemplated that many changes and modifications may be made, by one of ordinary skill in the art, without departing from the spirit and scope of the invention as disclosed above.

A method and apparatus for digitally analyzing continuous visual images, particularly with reference to the detection of mammalian cell mitotic events is disclosed. The visual images are analyzed by first extracting high frequency picture components, threshold comparison of such components and probing for annular objects indicative of putative mitotic cells. The detection of annulae is performed by an algorithm for recognizing rings of differential radii and compensating for other variations. Thereafter, spatial and temporal relationships between such objects is stored and compared to determine whether cell division occurred.

BACKGROUND 1. Field of the Invention The present invention relates to a focus detection device that is used on cameras, videos, and the like. 2. Background of the Related Art Phase difference detection-type focus detection devices for cameras are commonly known. FIG. 14 is a schematic diagram of a conventional phase difference detection-type focus detection device. Incident light rays from area 101 of the photo lens 100 pass a field of field mask 200, a field lens 300, an aperture stop 401, and an re-imaging lens 501. The rays are then composed into an image on an image sensor array A. The photoelectric converting elements are arranged linearly to form a row and generate outputs according to the incident light intensity. In the same manner, incident light rays from area 102 of the photo lens 100 pass the field of field mask 200, the field lens 300, an aperture stop 402, and an re-imaging lens 502, and are composed into an image on an image sensor array B. The pair of subject images composed on the image sensor array rows A and B diverge in the so-called front focus condition, in which the photo lens 100 forms a clear image of the subject in front of a predetermined focus surface. The pair of subject images converge in the so-called back focus condition, in which a clear image of the subject is formed behind the predetermined focus surface. In a focused condition, a clear image of the subject is formed exactly at the predetermined focus surface and the subject images on the image sensor array row A and row B coincide relative to each other. The pair of subject images on image sensor array rows A and B undergo photoelectric conversion and are converted to electrical signals. By mathematically processing these signals, the relative positions of the two subject images can be calculated, and the focus adjustment condition, i.e., the amount and direction of separation from the focused condition of the object lens 100 (referred to hereafter as "the defocus amount") can be determined. The projected images formed by the re-imaging lenses 501,502 on the image sensor array rows A and B, respectively, overlap in the vicinity of a predetermined focus surface. As shown in FIG. 13, this area of overlap is generally the area shown by the dotted lines in the central region of the photographic field, and is referred to as the "focus detection area." The mathematical processing method for calculating the defocus amount is described next. The image sensor array rows A and B each comprise a plurality of photoelectric converting elements having a plurality of output signal strings a[1], . . . ,a[n] and b[1], . . . ,b[n], respectively (refer to FIGS. 15(a), 15(b)). Correlation calculations are carried out while the data in a specified area within the pair of output signal strings of rows A and B are shifted a fixed amount. The L range, i.e., data line shift amount range, in which a maximum shift number is taken to be lmax, becomes -lmax to lmax. Specifically, the correlation amount C [L] is calculated through the following Formula 1. C [L]=Σ|a[i+L]-b[i]| (1) where L=-lmax, . . . ,-2,-1,0,1,2, . . . ,lmax and Σ indicates the summation of i=k to r. In Formula 1, L is an integer corresponding to the data line shift amount described above. The initial value k and the final value r depend on the shift amount L, as shown, for example, in the following Formula 2: When L≧0: k=k0+INT {-L//2} r=r0+INT {-L//2} When L<0: k=k0+INT {(-L+1)/2} r=r0+INT {(-L+1)/2} (2) where k0 and r0 are the initial and final values, respectively, when the shift amount L is 0. The combination of signals used to calculate the absolute value of the difference between the row A signals and the row B signal in Formula 1 when the initial value k and the final value r are calculated by Formula 2 are shown in FIGS. 16(a)-16(e). Thus, along with the change in the shift amount L, the ranges used for the correlation calculations for rows A and B shift in opposite directions relative to each other. The initial value k and the final value r can also be set regardless of the shift amount L. In this case, the range used for the correlation calculation of one line is continually fixed, and only the other line shifts. Since the relative position shift amount becomes the shift amount L when a pair of data match, the shift amount which gives the local minimum correlation amount C[L] is determined. This amount, coupled with a constant determined by the optical system and the pitch width of the photoelectric converting elements of the image sensor arrays, becomes the defocus amount. Thus, the larger the maximum shift number lmax, the larger the defocus amount for which detection can be carried out. The correlation amounts C[L] are scattered values, and the smallest unit of the defocus amount that can be detected is limited by the pitch width of the photoelectric converting elements of the image sensor array rows A and B. To overcome this limitation, a method is disclosed by the present assignee in Japanese Unexamined Patent Application Sho 60-37513 corresponding to U.S. Pat. No. 4,561,749, in which a new local minimum value Cex is calculated by interpolating from the scattered correlation amounts C[L]. The new local minimum value Cex is then used in carrying out detailed focus detection. As shown in FIG. 17, this method calculates the true local minimum value Cex and the shift amount Ls corresponding to Cex through Formula 3 and Formula 4, respectively, using the correlation amount C[l], i.e., the minimum value of the correlation amounts, and the correlation amounts C[l+1] and C[l-1], i.e., the shift amounts on either side of the correlation amount C [l]. DL=(C[l-1]-C[l+1])/2 Cex=C[l]-|DL| E=MAX [{C[l+1]-C [l], C[l-1]-C[l]}] (3) Ls=1+DL/E (4) In Formula 3, MAX {Ca, Cb} means that the larger value of Ca and Cb is selected. The defocus amount DF is calculated from the above mentioned shift amount Ls according to Formula 5. DF=Kf×Ls (5) In Formula 5, Kf is a constant that depends on the optical system used and the pitch width of the photoelectric converting elements of the image sensor arrays. It is also necessary to determine whether the defocus amount thus obtained indicates the true defocus amount, or whether the determined defocus amount is the result of noise or the like. A determined defocus amount that satisfies the following Formula 6 is considered to be reliable. E>E1 & Cex/E<G1 (6) where E1 and G1 are specified threshold values. The numerical value E is a value that indicates the changed state of the correlation amount and depends on the contrast of the subject; the larger the value, the higher the contrast and the higher the reliability. Cex is the difference when the pair of data most closely coincide, and is initially 0. However, due to the influence of noise and because of parallax generated by areas 101,102, Cex will not be 0. Because higher contrast results in a smaller influence from noise, Cex/E is used as the numerical value that indicates the degree of coincidence of a pair of data. Obviously, the closer the value of Cex/E is to 0, the higher the degree of coincidence of the data pair and the higher the reliability. Instead of the numerical value E, the contrast relating to one of the pair of data can be calculated and the reliability evaluation carried out using this calculated contrast. When reliability is ascertained, the photo lens 100 is driven or a display is carried out based on the defocus amount DF. The above Formulas 1-6, consisting of correlation calculations, interpolation calculations, and conditional evaluations, are referred to, in general, as the focus detection calculations. In the focused condition of the photo lens 100, since focus detection devices are generally structured so that a pair of data will coincide when the shift amount L is virtually 0, the photo lens 100 cannot be focused on the subject if the subject images are not formed in the range from the initial value k0 to the final value r0 of the image sensor array row A and row B. Therefore, the area in which focus detection is carried out is established through the initial value k0 and the final value r0. For example, if the initial value k0 and the final value r0 are taken to be a portion of the central area of the photographic field, the area in which focus detection is carried out becomes the area shown by the solid lines in the central area of the photographic field, as shown in FIG. 13. Hereafter, the data range from the initial value k0 to the final value r0 will be called the calculation range. The area corresponding to the calculation range in the photographic field is the focus detection area. The photographer can focus the photo lens on the desired subject by capturing the subject within the focus detection area. The focus detection device may be provided with a switching device that can switch between a wide mode, which takes virtually the entire image sensor array as the focus detection area, and a spot mode, which takes the center portion of the sensor array as the focus detection area. In the wide mode, the initial value k0 and the final value r0 are set so that the calculating range will widen. In the spot mode, the initial value k0 and the final value r0 are set so that the calculation range will narrow. The output signal strings a[1], . . . ,a[n] and b[1], . . . ,b[n] of the image sensor array rows A and B, respectively, may be directly used in the focus detection calculations. However, because there are cases in which a correct focus detection cannot be accomplished because of the presence of frequency components higher than the Nyquist frequency of the subject, or because of the influence of unbalanced outputs of rows A and B, filtering of the output data strings if preferred. A method is disclosed by the present assignee in Japanese Unexamined Patent Application Sho 61-245123 in which a filter calculation procedure is performed on the output signal strings. Focus detection calculations are then carried out using the obtained filter procedure data. For example, a filter procedure calculation that removes the high frequency components above the Nyquist frequency is achieved by Formula 7. The filter processing data Pa[1], . . . ,Pa[n-2] and Pb[1], . . . ,Pb[n-2] are obtained from the output signal strings a[1], . . . ,a[n] and b[1], . . . ,b[n] of the rows A and B, respectively. Pa[i]=(a[i]+2xa[i+1]+a[i+2])/4 Pb[i]=(b[i]+2xb[i+1]+b[i+2])/4 (7) where i=1 to n-2. A subsequent filter procedure calculation is performed on the filter processing data Pa[1], . . . ,Pa[n-2] and Pb[1], . . . ,Pb[n-2] which removes the influence of unbalanced outputs of the row A and the row B. This calculation is carried out, for example, according to Formula 8, and the filter processing data Fa[1], . . . ,Fa[n-2-2s] and Fb[1], . . . ,Fb[n-2-2s] are obtained. Fa[i]=-Pa[i]+2xPa[i+s]-Pa[i+2s] Fb[i]=-Pb[i]+2xPb[i+s]-Pb[i+2s] (8) where i=1 to n-2-2s In Formula 8, s is an integer from 1 to 10. The higher the numerical value, the lower the frequency component that is extracted from the subject pattern; the lower the numerical value, the higher the frequency component that is extracted from the subject pattern. In addition, the number of filter processing data decreases as s increases. Since the subject image includes more high frequency components as the focused condition is approached, it is desirable to have a comparatively small value for s; and since the subject image blurs in the un-focused condition and has only low frequency components, a large value of s is desirable. Therefore, when s is small, since the low frequency components are not extracted, detection becomes impossible when the defocus amount is large. In this case, it is meaningless to have a very large maximum shift number lmax in Formula 1; a comparatively small value will suffice. Conversely, when s is large, detection is possible even when the defocus amount is large because the low frequency components are extracted. Therefore, a comparatively large value is set for lmax. In addition, when the value of s is comparatively large, the filter processing data Fa[i] and Fb[i] obtained through Formula 8 may each be halved by taking every other datum. When this is done, since 2 pixel widths are held in one datum, only half the calculation range is needed for the same focus detection area. Since shift amount 1 of the case where the data is halved corresponds to shift amount 2 of the case where the data is not halved, a defocus amount of the same size can be detected even though the maximum shift number is only half. FIGS. 18(a)-18(c) graphically illustrate a subject pattern that is formed only from low frequency components. FIG. 18(a) displays the output signal, FIG. 18(b) displays the filter processing data with s=2, and FIG. 18(c) displays the filter processing data with s=8. Since the system is in the focused condition in these drawings, the row A output signal string and the row B output signal string overlap. As shown in the figures, the filter processing data with s=2 has virtually no contrast and is virtually flat. When s=8, the contrast becomes sufficient and a reliable defocus amount can be obtained. As shown in FIG. 18(c), since the wide calculating range ce2 includes more contrast than the narrow calculating range ce1, ce2 is more advantageous for focus detection calculations. In other words, the wider calculating range is desirable for filter processing data for which low frequency components are extracted. FIGS. 19(a)-19(c) graphically illustrate an example of a subject pattern that is formed only by high frequency components. FIG. 19(a) shows the output signal, FIG. 19(b) shows the filter processing data with s=2, and FIG. 19(c) shows the filter processing data with s=8. Since the system is in the focused condition in these drawings, the row A output signal string and the row B output signal string overlap. In this case, sufficient contrast is obtained by filter processing data with s=2, and a reliable defocus amount can be obtained. In FIG. 19(b), when the narrow calculating range ce1 and the wide calculating range ce2 are compared, the contrast is the same for both. However, the influence of noise is less for the narrow calculating range. Further, if the range is too wide, multiple subjects with different distances may exist within the calculating range making focus detection impossible. Therefore, it is desirable to use a comparatively narrow calculating range for the filter processing data having high frequency components extracted. FIGS. 20(a)-20(c) graphically illustrate an example of a subject pattern that includes adequate high frequency and low frequency components. FIG. 20(a) shows the output signal, FIG. 20(b) shows the filter processing data with s=2, and FIG. 20(c) shows the filter processing data with s=8. Since the system is in the focused condition in these drawings, the row A output signal string and the row B output signal string overlap. In this example, sufficient contrast may be obtained regardless of the value of s. In addition, as s increases, the range over which the contrast of the subject pattern is distributed becomes wider. FIGS. 21(a)-21(c) graphically illustrate a case in which the defocus amount is large. This is the image sensor output which would occur, for example, in the case of a subject such as a chimney. FIG. 21(a) shows the output signal, FIG. 21(b) shows the filter processing data with s=2, and FIG. 21(c) shows the filter processing data with s=8. In addition, the solid line shows the output signal string of the row A, and the dashed line shows the output signal string of the row B. Thus, since virtually no high frequency components are included when the defocus amount is large, no contrast can be obtained by filter processing data with s=2. However, sufficient contrast can be obtained through filter processing data with s=8. The maximum shift number lmax is given a sufficiently large value, and the defocus amount can be detected. Since the frequency components differ according to the subject pattern, s is initially set to s=2 and a filtering process is carried out that extracts high frequency components. The focus detection calculations of Formulas 1-6 are carried out using this filter processing data, and if a reliable defocus amount is obtained, the focus detection action stops. If a reliable defocus amount is not obtained, s is changed to 4 and a filtering process is carried out that extracts lower frequency components. The focus detection calculations of Formula 1-6 are then repeated using this filter processing data. The value of s is increased through this type of process until a reliable defocus amount is obtained. According to the above method, since high frequency components are extracted first, in subject patterns that are near the normal focused condition of the subject, such as the subject pattern shown in FIG. 20(a), a reliable defocus amount can be obtained. When the subject consists only of low frequency components, e.g. a human face, and has for example a subject pattern such as that shown in FIG. 18(a), the focus detection calculations are carried out based on filter processing data having low frequency components extracted. As shown in FIGS. 21(a)-21(c), in the case of a large defocus amount, filter processing data having low frequency components extracted are used. The maximum shift number lmax is increased, the focus detection calculations are carried out, and the defocus amount can be detected. Since the calculation time is shortened near the focused condition, the subject can be easily followed even when the subject is a moving object. For those focus detection devices that do not perform a filter process and instead directly use the output signal strings, or which only use a filter process that removes frequency components that are higher than a specific frequency, e.g the Nyquist frequency, a wide focus detection area is desirable for subject patterns that consists only of low frequency components, and a comparatively narrow focus detection area is desirable for subject patterns that include high frequency components. Therefore, the focus detection calculations are first carried out with a narrow focus detection area, and then, if a reliable defocus amount is not obtained, the focus detection calculations are carried out again with a wide focus detection area. With the focus detection devices described above, the following problems may arise. First, when the focus detection device switches the type of filter process for the output signal strings of the image sensors, proper ranges are provided for each filter process. However, the photographer may mistake the widest calculating range among these ranges for the focus detection area. For example, in the pattern shown in FIG. 20(a), since the filter processing data for s=2 has sufficient contrast in the calculation range established by the initial value k0 and the final value r0, as shown in FIG. 20 (b), a reliable defocus amount can be obtained. However, if the subject pattern shown in FIG. 20(a) is shifted, such as shown in FIG. 22(a), the range of filter processing data does not have any contrast in the calculation range established by the initial value k0 and the final value r0 as shown in FIG. 22(b). Consequently, a reliable defocus amount cannot be obtained for s=2. However, as shown in FIG. 22(c), using filter processing data with s=8, since the contrast range widens into the range established by the initial value k0 and the final value r0, sufficient contrast exists and a reliable defocus amount is obtained. Thus, the photographer is given a wide calculation range appropriate for filter processing data having low frequency components extracted, and can distinguish the focus detection area from the portion in which the range with contrast is widened through filter processing. Even when the value of s is set to be optimal for a subject pattern, the calculated result for a subject pattern that consists only of low frequency components generally has a lower precision than the calculated result for a subject pattern that includes high frequency components. As described above, in filter processing with a comparatively large value of s, when the number of filter processing data Fa[i] and Fb[i] is halved, since two pixel widths are held in one datum, the precision of the interpolation calculations of Formulas 3 and 4 decreases and results in a noticeable decline in focus detection precision. Further, in the case shown in FIG. 22(c), since not all of the subject contrast is inside the calculation range, a defocus amount is obtained which is unstable. Consequently, a flickering display and so-called hunting in which the lens is slightly oscillated without stopping at the focused condition results. When the subject pattern shown in FIG. 20(a) is moved gradually from the center of the photographic field toward the outside, a stable defocus amount is initially obtained from filter processing data with s=2. However, when contrast disappears from the calculation range, the defocus amount is then calculated based on filter processing data for which lower frequency components are extracted, and an unstable defocus amount is obtained. Furthermore, when the subject pattern is moved to the outside, the contrast included in the calculation range decreases, instability increases, and if the pattern is moved to far, focus detection becomes impossible. If the narrow region corresponding to the calculation range for filter processing data having high frequency components extracted is taken as the focus detection area, and a focus detection frame is displayed on the finder screen of the camera, focus detection carried out outside the focus detection frame will result in a defocus amount that is unstable. On the other hand, if the wide region corresponding to the calculation range for filter processing data having low frequency extracted is taken as the focus detection area, and a focus detection frame is displayed on the finder screen of the camera, since focus detection is carried out while a portion of the subject contrast is outside the frame, instability results. In focus detection devices that do not perform filter processing, or that only carry out filter processing that removes frequency components higher than the Nyquist frequency, the influence of noise is less in the narrow calculation range than in the wide calculation range. As a result, the defocus amount obtained through the wide calculation range becomes unstable compared to the defocus amount obtained through the narrow calculation range, and the same problem occurs as described above. In focus detection devices in which it is possible to switch between a wide mode and a spot mode, the calculation ranges for filter processing having high frequency components extracted may be variable. However, when the calculation range for filter processing data having low frequency components extracted is narrowed because the device is in the spot mode, when the subject consists of low frequency components, the contrast included in the calculation range decreases by the amount that the calculation range has become narrow. This can result in an unstable defocus amount with focus detection becoming impossible, and different focus detection capabilities for subjects with only low frequency components in the wide and spot modes. Therefore, if one decides to continually use a wide calculation range regardless of the mode, the perceived focus detection area will widen as described above, even in the spot mode, and there will be virtually no difference from the focus detection area in the wide mode. Another problem will be described using FIG. 23. FIG. 23 shows the image sensor output when focusing is performed on a subject such as two chimneys. The contrast is formed only at the two ends of the image sensor array. There is no contrast in the calculating range using data for which filter processing with s=2 is performed, and detection becomes impossible since the maximum shift number lmax is small. However, since the maximum shift number lmax is large for filter processing data with s=8, when the shift amount L is large, the right side row A contrast, for example, coincides with the left side row B contrast, and the defocus amount ends up being calculated based on the correlation amount at a large shift amount even though the system is in the focused condition. This results in so-called false focus, in which the photo lens focuses in an abnormally blurred condition. This problem may be resolved by decreasing the maximum shift number lmax in the correlation calculation of Formula 1. However, with this solution, when the defocus amount is large as shown in FIG. 21, focus detection becomes impossible. SUMMARY OF THE INVENTION An object of the present invention is to provide a focus detection device in which reliable defocus amounts are obtained, detection capability for low frequency subjects does not decrease, detection efficiency does not decrease for large defocus amounts, and false focussing and hunting are prevented. In addition, it is an object of the invention to provide a focus detection device that can switch between a spot mode and a wide mode wherein the difference between the focus detection areas of the wide mode and the spot mode is clear and there is no difference in the detection capabilities of the two modes for low frequency subjects. In order to achieve the above and other objects of the invention, a focus detection device in accordance with a first embodiment of the invention includes an output device that outputs a pair of signal strings and includes at least a pair of photoelectric converting element arrays. A focus detection optical system conducts a pair of light rays from a subject that has passed the photo lens to the pair of photoelectric converting element arrays. A calculation range setting device sets a range of signals within the pair of signal strings and a focus detection calculating device calculates a focus adjustment condition for the photo lens based on the signal range set by the calculation range setting device. A contrast calculation device calculates a contrast based on signals of at least one of the signal strings that are excluded from the signal range set by the calculation range setting device, wherein the operation of the focus detection calculating device is dependent upon the calculated contrast. In accordance with another embodiment of the invention, the focus detection device includes a filter that extracts a pair of signal strings having a predetermined frequency component from a pair of signal strings output by the photoelectric converting element arrays, wherein the extracted pair of signal strings are the signal strings output by the output device. In accordance with a still further embodiment, if the calculated contrast exceeds a specified value, the focus detection calculating device will not carry out a focus detection calculation based on signal strings having components less than a predetermined frequency. In accordance with another embodiment, if a calculated contrast exceeds a specified value, the focus detection calculating device narrows a shift range for a focus detection calculation based on the signal strings having components less than a predetermined frequency. In accordance with a still further embodiment, a reliability evaluating device is provided that compares a value calculated by the focus detection calculating device with a pre-set threshold value and evaluates the reliability of a calculated defocus amount. If a calculated contrast exceeds a specified value, the reliability evaluating device changes the threshold value for the focus detection calculation based on the pair of signal strings having components less than a predetermined frequency. In accordance with another embodiment, if a calculated contrast exceeds a specified value, the calculation range setting device narrows the range for a focus detection calculation based on the pair of signal strings that having lower frequency components. BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described in detail with reference to the following drawings in which like reference numerals refer to like elements and wherein: FIG. 1 is a block diagram illustrating the structure according to a first embodiment of the invention; FIGS. 2(a)-2(c) are schematic diagrams illustrating the calculation ranges of the first embodiment; FIG. 3 is a flow chart of the first operation of the first embodiment; FIG. 4 is a flow chart of the second operation of the first embodiment; FIG. 5 is a flow chart of the third operation of the first embodiment; FIG. 6 is a block diagram illustrating the structure of the second embodiment; FIGS. 7(a)-7(c) are schematic diagrams illustrating the calculation ranges of the second embodiment; FIG. 8 is a flow chart of the entire operation of the second embodiment; FIG. 9 is a flow chart of the operation of the first spot mode of the second embodiment; FIG. 10 is a flow chart of the operation of the second spot mode of the second embodiment; FIG. 11 is a flow chart of the operation of the third spot mode of the second embodiment; FIG. 12 is a flow chart of the operation of the wide mode of the second embodiment; FIG. 13 is a schematic diagram illustrating the relationship of the positions of a conventional photographic field and focus detection region; FIG. 14 is a schematic diagram illustrating the structure of a conventional focus detection optical system; FIGS. 15(a)-15(c) are graphs describing a conventional focus detection calculation; FIGS. 16(a)-16(e) are schematic diagrams describing a conventional correlation calculations for various shift amounts; FIG. 17 is a graph illustrating a conventional focus detection calculation; FIGS. 18(a)-18(c) are graphs that shows an example of a subject pattern that consists only of low frequency components; FIGS. 19(a)-19(c) are graphs that shows an example of a subject pattern that consists only of high frequency components; FIGS. 20(a)-20(c) are graphs that shows an example of a subject pattern that includes high frequency components and low frequency components; FIGS. 21(a)-21(c) are graphs that shows an example of a subject pattern when the defocus amount is large; FIGS. 22(a)-22(c) are graphs that shows a case in which the subject pattern is shifted to the side; and FIG. 23 is a graph illustrating the case in which a subject pattern exists only at the sides of the sensor. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Preferred embodiments of the present invention are described hereafter with reference to the drawings. FIG. 1 is a block diagram that shows the structure of a first embodiment. The focus detection optical system 1 is an optical system that conducts light from a subject that has passed a photo lens 100 to the image sensor 2. The focus detection optical system is formed, for example, by a field of field mask 200, a field lens 300, aperture stops 401 and 402, and re-imaging lenses 501 and 502, as shown in FIG. 14. The image sensor 2 includes a pair of image sensor arrays, e.g., rows A and B. Each array may consist of, for example, 52 photoelectric converting elements. The arrays output signal strings a[i] and b[i] corresponding to rows A and B, respectively, wherein each signal string consists of 52 data bits. The mathematical processing circuit 3 includes a filter processing circuit 3a, a calculation range setting circuit 3b, a threshold value setting circuit 3c, a maximum shift number setting circuit 3d, and a focus detection calculating circuit 3e. The filter processing circuit 3a performs a filter procedure according to Formula 7 and Formula 8 for the output signal strings a[i] and b[i] of the image sensor 2 and outputs filter processing data Fa[i] and Fb[i]. The output signal strings a[i] and b[i] are filtered according to Formula 7 to remove high frequency components above the Nyquist frequency. This filtering procedure produces filter processing data Pa[i] and Pb[i], for each of which 50 high frequency components have been cut. Further filter processing data Fa[i] and Fb[i] are generated according to Formula 8, wherein Fa[i] and Fb[i] each having 46 data bits when s=2, 42 data bits when s=4, and 34 data bits when s=8. The calculation range setting circuit 3b establishes the calculation range by setting the initial value k0 and the final value r0 according to the kind of filter processing. FIGS. 2(a)-2(c) show the calculation ranges set for cases in which s=2, s=4, and s=8, respectively, in Formula 8. When s=2, k0=17 and r0=30; when s=4, k0=16 and r0=27; when s=8, k0=4 and r0=31. The focus detection frame displayed on the finder screen of the camera is taken as the area that corresponds to the above-mentioned calculation range for s=2. Hereafter, this area is referred to simply as the focus detection area. In the second operation (described hereafter), in the case shown in FIG. 2(c) for which s=8, when it is determined through the contrast determining circuit 4 (described hereafter) that a strong contrast exists outside the focus detection area, the range of k0=13 and r0=22, which is shown by the dotted line and which is different from the above-mentioned calculation range, is used as the calculation range. The threshold value setting circuit 3c sets the threshold values E1 and G1 used in Formula 6. The values of the threshold values E1 and G1 differ according to the kind of filter processing, and are taken as E1=Ea and G1=Ga when s=2, E1=Eb and G1=Gb when s=4, and E1=Ec and G1=Gc when s=8. These threshold values have the following relationships: Ea≦Eb≦Ec, Gc≦Gb≦Ga (9) In the third operation (described hereafter), when it is determined through the contrast determining circuit 4 that a strong contrast exists outside the focus detection area, the threshold value for s=8 is set to a value that is more restrictive than the above-mentioned Ec. The maximum shift number setting circuit 3d sets the maximum shift number lmax in Formula 1. The maximum shift number lmax that is set differs according to the kind of filter processing. lmax=la when s=2, lmax=lb when s=4, and lmax=lc when s=8. These maximum shift numbers have the following relationship: la<lb<lc (10) In the second and third operations, (described hereafter), when it is determined through the contrast determining circuit 4 that a strong contrast exists outside the focus detection area, the maximum shift number for s=8 is set to a value that is smaller than the above-mentioned lc. The focus detection calculating circuit 3e carries out focus detection calculations according to Formula 1-6, using the filter processing data Fa[i] and Fb[i]. The focus detection calculation circuit 3e calculates the focus adjustment condition of the photo lens 100, i.e., the defocus amount. The contrast determining circuit 4 detects the contrast of the data at both sides of at least one of the image sensor array rows A and B, and determines whether there is a strong contrast outside the focus detection area. Specifically, contrast determining circuit 4 calculates the contrast in each region to the left and right of the calculation area of at least one of the filter processing data Fa[i] and Fb[i] obtained through the filter processing of Formula 8 using s=2 (here, the case will be described in which only Fa[i] is used). The difference between the maximum value and minimum value of the data (referred to hereafter as the PP value) is also calculated. The contrast determining circuit 4 then determines whether there is a strong contrast outside the focus detection area based on the obtained contrast and PP value. The calculation range for s=2 is from 17 to 30, and two contrast values Cnt[1] and Cnt[2] are calculated through Formula 11 in two ranges, i.e., 3 to 16 and 31 to 44, which are to the left and right, respectively, of this calculation range. Cnt[1]=Σ|Fa[i]-Fa[i+1]|, where Σ indicates the summation from i=3 to 15. Cnt[2]=Σ|Fa[i]-Fa[i+1]| where Σ indicates the summation from i=31 to 43 (11) In Formula 11, when noise overlaps the output signal of the image sensor 2, Cnt[1] and Cnt[2] become comparatively large values even when the subject is exactly the same pattern. However, by replacing the values with 0 when the absolute value of Fa[i]-Fa[i+1] is smaller than a specified value, the noise components can be removed. In addition, the PP values PtP[1] and PtP[2] are calculated in each range to the left and right of the calculation range as follows: PtP[1]=Max {Fa[3] to Fa[16]}-Min {Fa[3] to Fa[16]}, PtP[2]=Max {Fa[31] to Fa[44]}-Min {Fa[31] to Fa[44]} (12) The contrast values Cnt[1] and Cnt[2] and the PP values PtP[1] and PtP[2] are then compared with specified threshold values STh1 and STh2. When the following conditions are satisfied, it is determined that a strong contrast exists outside the focus detection area. If the following conditions are not satisfied, it is determined that a strong contrast does not exist outside the focus detection area. Cnt[1]>STh1, or, Cnt[2]>STh1, or, PtP[1]>STh2, or, PtP[2]>STh2, where it is desirable that STh2<STh1 (13) In the case of a subject consisting only of low frequency components, such as the subject pattern shown in FIG. 18, the contrast using filter processing data for which high frequency components have been extracted with s=2 disappears completely, and it is determined through the above-mentioned evaluation that there is no strong contrast pattern outside the focus detection area. When the defocus is large, such as in the subject pattern shown in FIG. 21(a), since the patterns of the rows A and B shift together, an area with contrast comes into existence outside the focus detection area. However, since the subject image is blurred because the defocus amount is large, high frequency components are not included, the contrast disappears when filter processing data is used for which high frequency components have been extracted with s=2, and it is determined through the above-mentioned evaluation that there is no strong contrast pattern outside the focus detection area. Conversely, in the focused condition, such as the patterns shown in FIGS. 22(a) and 23, since high frequency components are included, a contrast is obtained with filter processing data for which high frequency components have been extracted with s=2, and it is determined through the above-mentioned evaluation that there is a strong contrast pattern outside the focus detection area. Thus, by using filter processing data for which high frequency components are extracted for the contrast evaluation, in cases in which the defocus amount is large and a blurred subject image exists outside the focus detection area it will be determined that there is no strong contrast. The mathematical processing circuit 3 and the contrast determining circuit 4 may be embodied in a micro-computer. The operation of the first embodiment will be described with reference to FIGS. 3-5. FIG. 3 is a flow chart that shows the first operation of the first embodiment. In this first operation, when it is determined through the contrast determining circuit 4 that there is a strong contrast outside the focus detection area, a focus detection calculation based on filter processing data for which low frequency components are extracted is prevented. In step S101, output signal strings a[i] and b[i] are input from the image sensor 2. The program then proceeds to step S102 and calculates filter processing data Pa[i] and Pb[i] through Formula 7. In step S103, the value of s in Formula 8 is set to 2, and in step S104, filter processing data Fa[i] and Fb[i] are calculated by executing the filter calculation according to Formula 8. In step S105, the following values are set: initial value k0=17, final value r0=30, threshold value E1=Ea, threshold value G1=Ga, and the maximum shift number lmax=la. In step S106, the focus detection calculations of Formulas 1-6 are executed using the calculation range, threshold values, and maximum shift number set in the preceding step. In step S107, it is determined whether a reliable defocus amount is obtained. If a reliable defocus amount is obtained, the program advances to step S121, focus detection is determined to be possible, and the operation ends. Conversely, if a reliable defocus amount is not obtained, the program proceeds to step S108, calculates the contrast outside the focus detection area and the PP value through Formulas 11 and 12, respectively, and determines through Formula 13 whether a strong contrast exists outside the focus detection area. In step S109, the s value in Formula 8 is set to 4. The program proceeds to step S110 and calculates filter processing data Fa[i] and Fb[i] according to Formula 8. In step S111, the following values are set: initial value k0=16, final value r0=27, threshold value E1=Eb, threshold value G1=Gb, and the maximum shift number lmax=lb. In step S112, the focus detection calculations of Formulas 1-6 are executed using the calculation range, threshold values, and maximum shift number set in the preceding step. In step S113, it is determined whether a reliable defocus amount is obtained. If a reliable defocus amount is obtained, the program advances to step S121, focus detection is determined to be possible, and the operation ends. If a reliable defocus amount is not obtained, the program proceeds to step S114. In step S114, if it is determined in step S108 that a strong contrast does not exist outside the focus detection area, the program proceeds to steps S115-S118, in which a focus detection calculation is carried out based on filter processing data for which lower frequency components are extracted. In step S115, the s value in Formula 8 is set to 8. The program proceeds to step S116 and calculates filter data Fa[i] and Fb[i] according to Formula 8. In step S117, the following values are set: initial value k0=4, final value r0=31, threshold value E1=Ec, threshold value G1=Gc, and the maximum shift number lmax=lc. In step S118, the focus detection calculations of Formulas 1-6 are executed using the calculation range, threshold values, and maximum shift number set in the preceding step. Next, in step S119, it is determined whether a reliable defocus amount is obtained. If a reliable defocus amount is obtained, the program proceeds to step S121, focus detection is possible, and the operation ends. Conversely, if a reliable defocus amount is not obtained, the program proceeds to step S120, focus detection is determined to be impossible, and the operation ends. If it is determined in step S114 that a strong contrast does exist outside the focus detection area, a focus detection calculation based on filter processing data for which even lower frequency components are extracted is prevented, the program advances to step S120, focus detection is determined to be impossible, and the operation ends. According to the first operation, in the case of the subject patterns shown in FIG. 22(a) and FIG. 23, since a focus detection calculation based on filter processing data for which low frequency components have been extracted with s=8 is not carried out because strong contrast exists outside the focus detection area, focus detection becomes impossible. In the case of the subject patterns shown in FIG. 21 and FIG. 18, since a focus detection calculation is executed based on filter processing data for which low frequency components have been extracted with s=8 because strong contrast does not exist outside the focus detection area, focus detection becomes possible and a defocus amount can be detected. Steps S101-S104, S109, S110, S115, and S116 are operations of the filter processing circuit 3a; steps S105, S111, and S117 are operations of the calculation range setting circuit 3b, the threshold value setting circuit 3c, and the maximum shift number setting circuit 3d. Steps S108 and S114 are operations of the contrast determining circuit 4, and all other steps are operations of the focus detection calculating circuit 3e. FIG. 4 is a flow chart that shows a variation of the first operation of the first embodiment (hereafter called the second operation of the first embodiment). In the second operation, when it is determined through the contrast determining circuit 4 that there is a strong contrast outside the focus detection area, the calculation range is narrowed in the focus detection calculation based on filter processing data for which low frequency components have been extracted with s=8, the maximum shift number is decreased, and the shift range is narrowed. In step S201, output signal strings a[i] and b[i] are input from the image sensor 2. The program then proceeds to step S202 and calculates filter processing data Pa[i] and Pb[i] through Formula 7. In step S203, the value of s in Formula 8 is set to 2, and in step S204, filter processing data Fa[i] and Fb[i] are calculated by executing the filter calculation according to Formula 8. In step S205, the following values are set: initial value k0=17, final value r0=30, threshold value E1=Ea, threshold value G1=Ga, and the maximum shift number lmax=la. In step S206, the focus detection calculations of Formulas 1-6 are executed using the calculation range, threshold values, and maximum shift number set in the preceding step. In step S207, it is determined whether a reliable defocus amount is obtained. If a reliable defocus amount is obtained, the program advances to step S222, focus detection is determined to be possible, and the operation ends. Conversely, if a reliable defocus amount is not obtained, the program proceeds to step S208. In step S208, the program calculates the contrast outside the focus detection area and the PP value through Formula 11 and Formula 12, respectively, and determines through Formula 13 whether a strong contrast exists outside the focus detection area. In step S209, the s value in Formula 8 is set to 4, and in step S210, filter processing data Fa[i] and Fb[i] are calculated by executing the filter calculation according to Formula 8. In step S211, the following values are set: initial value k0=16, final value r0=27, threshold value E1=Eb, threshold value G1=Gb, and the maximum shift number lmax=lb. In step S212, the focus detection calculations of Formulas 1-6 are executed using the calculation range, threshold values, and maximum shift number set in the preceding step. In step S213, it is determined whether a reliable defocus amount is obtained. If a reliable defocus amount is obtained, the program advances to step S222, focus detection is determined to be possible, and the operation ends. Conversely, if a reliable defocus amount is not obtained, the program proceeds to step S214 and sets the s value to 8. Next, in step S215, filter processing data Fa[i] and Fb[i] are calculated by Formula 8. In step S216, if it is determined in the above-mentioned step S208 that strong contrast does not exist outside the focus detection area, the program proceeds to step S217, in which a wide calculation range and a large maximum shift number are set; if it is determined that strong contrast does exist outside the focus detection area, the program proceeds to step S218, in which a narrow calculation range and a small maximum shift number are set. In step S217, the following values are set: initial value k0=4, final value r0=31, threshold value E1=Ec, threshold value G1=Gc, and the maximum shift number lmax=lc. Alternatively, in step S218 the following values are set: initial value k0=13, final value r0=22, threshold value E1=Ec, threshold value G1=Gc, and the maximum shift number lmax=lc/2. In step S219, the focus detection calculations of Formulas 1-6 are executed using the calculation range, threshold values, and maximum shift number set in the preceding step S217 or step S218. In step S220, it is determined whether a reliable defocus amount is obtained. If a reliable defocus amount is obtained, the program proceeds to step S222, focus detection is possible, and the operation ends. Conversely, if a reliable defocus amount is not obtained, the program proceeds to step S221, focus detection is determined to be impossible, and the operation ends. According to the second operation, in the case of the subject patterns shown in FIG. 22 and FIG. 23, since strong contrast exists outside the focus detection area, a focus detection calculation based on filter processing data for which low frequency components are extracted is carried out with a narrow calculation range and a small maximum shift number. In the case of the subject pattern shown in FIG. 22, since focus detection is carried out for an area with no contrast because the calculation range has become narrow, focus detection becomes impossible. In the case of the subject pattern shown in FIG. 23, since a correlation amount is not calculated for a shift amount that will result in false focus, focus detection becomes impossible through the setting of a small maximum shift number. In the case of the subject patterns shown in FIG. 21 and FIG. 18, since a focus detection calculation based on filter processing data for which low frequency components are extracted is carried out with a wide calculation range and a large maximum shift number because strong contrast does not exist outside the focus detection area, focus detection becomes possible and a defocus amount can be detected. In the above-mentioned step S218, the example was shown in which the maximum shift number was decreased to 1/2 of the normal value. However, the decrease in the maximum shift number is not limited to this amount. Steps S201-S204, S209, S210, S214, and S215 are operations of the filter processing circuit 3a; steps S205, S211, S217, and S218 are operations of the calculation range setting circuit 3b, the threshold value setting circuit 3c, and the maximum shift number setting circuit 3d. Steps S208 and S216 are operations of the contrast determining circuit 4, and all other steps are operations of the focus detection calculating circuit 3e. FIG. 5 is a flow chart that shows another variation of the first operation of the first embodiment (hereafter called the third operation of the first embodiment). In this third operation, when it is determined through the contrast determining circuit 4 that there is a strong contrast outside the focus detection area, the threshold values are made more restrictive for the focus detection calculation based on filter processing data for which low frequency components are extracted, the maximum shift number is decreased, and the shift range is narrowed. In step S301, output signal strings a[i] and b[i] are input from the image sensor 2. The program then proceeds to step S302 and calculates filter processing data Pa[i] and Pb[i] through Formula 7. In step S303, the value of s in Formula 8 is set to 2, and in step S304, filter processing data Fa[i] and Fb[i] are calculated by executing the filter calculation according to Formula 8. In step S305, the following values are set: initial value k0=17, final value r0=30, threshold value E1=Ea, threshold value G1=Ga, and the maximum shift number lmax=la. In step S306, the focus detection calculations of Formulas 1-6 are executed using the calculation range, threshold values, and maximum shift number set in the preceding step. In step S307, it is determined whether a reliable defocus amount is obtained. If a reliable defocus amount is obtained, the program advances to step S322, focus detection is determined to be possible, and the operation ends. Conversely, if a reliable defocus amount is not obtained, the program proceeds to step S308, calculates the contrast outside the focus detection area and the PP value through Formula 11 and Formula 12, respectively, and determines through Formula 13 whether a strong contrast exists outside the focus detection area. In step S309, the s value in Formula 8 is set to 4, and in step S310, filter processing data Fa[i] and Fb[i] are calculated according to Formula 8. In step S311, the following values are set: initial value k0=16, final value r0=27, threshold value E1=Eb, threshold value G1=Gb, and the maximum shift number lmax=lb. In step S312, the focus detection calculations of Formulas 1-6 are executed using the calculation range, threshold values, and maximum shift number set in the preceding step. In step S313, it is determined whether a reliable defocus amount is obtained. If a reliable defocus amount is obtained, the program advances to step S322, focus detection is determined to be possible, and the operation ends. Conversely, if a reliable defocus amount is not obtained, the program proceeds to step S314 and sets the s value to 8. In step S315, filter processing data Fa[i] and Fb[i] are obtained by executing the filter calculation according to Formula 8. In step S316, if it is determined in the preceding steps that strong contrast does not exist outside the focus detection area, the program proceeds to step S317, in which a normal threshold value and a large maximum shift number are set; if it is determined that strong contrast does exist outside the focus detection area, the program proceeds to step S318, in which a restrictive threshold value and a small maximum shift number are set. In step S317, the following values are set: initial value k0=4, final value r0=31, threshold value E1=Ec, threshold value G1=Gc, and the maximum shift number lmax=lc. Alternatively, in step S318 the following values are set: initial value k0=4, final value r0=31, threshold value E1=2xEc, threshold value G1=Gc, and the maximum shift number lmax=lc/2. In step S319, the focus detection calculations of Formulas 1-6 are executed using the calculation range, threshold values, and maximum shift number set in the preceding step S317 or step S318. In step S320, it is determined whether a reliable defocus amount is obtained. If a reliable defocus amount is obtained, the program proceeds to step S322, focus detection is possible, and the operation ends. Conversely, if a reliable defocus amount is not obtained, the program proceeds to step S321, focus detection is determined to be impossible, and the operation ends. According to the third operation, since strong contrast exists outside the focus detection area in the case of the subject patterns shown in FIG. 22 and FIG. 23, a focus detection calculation based on filter processing data having low frequency components extracted is carried out with a restrictive threshold value and a small maximum shift number. In the case of the subject pattern shown in FIG. 22, since the threshold value becomes restrictive, there is no reliability even though contrast exists in the calculation range, and focus detection becomes impossible. In the case of the subject pattern shown in FIG. 23, since a correlation amount is not calculated for a shift amount that will result in false focus, focus detection becomes impossible through the setting of a small maximum shift number. In the case of the subject patterns shown in FIG. 21 and FIG. 18, since strong contrast does not exist outside the focus detection area, a focus detection calculation based on filter processing data having low frequency components extracted is carried out with a restrictive threshold value and a large maximum shift number. Consequently, focus detection becomes possible and a defocus amount can be detected. In step S318, only the threshold value E1 was set to be restrictive. However, the threshold value G1 may also be set to be restrictive. In addition, in step S318, the restrictive threshold value was set to twice the normal threshold value. However, the restrictive threshold value is not limited by the above-mentioned embodiment. Furthermore, instead of using the numerical value E, the contrast for one of a pair of data may be calculated, and the evaluation may be carried out using this value. Steps S301-S304, S309, S310, S314, and S315, are operations of the filter processing circuit 3a; steps S305, S311, S317, and S318 are operations of the calculation range setting circuit 3b, the threshold value setting circuit 3c, and the maximum shift number setting circuit 3d. Steps S308 and S316 are operations of the contrast determining circuit 4, and all other steps are operations of the focus detection calculating circuit 3e. In the third operation, a focus detection calculation based on filter processing data having low frequency components extracted is carried out with a wide calculation range even if strong contrast exists outside the focus detection area. However, it is also acceptable to set a narrow calculation range, as in the second operation. In the first embodiment, a first operation, and two variations thereof (i.e. the second and third operations) are disclosed as separately provided in a camera. However, it is also possible to provide any two or all three of the operations usable together in a single camera. Further, in the first through third operations described above, filters for processing the output signal strings were provided. However, the invention may be applied to focus detection devices directly using the output signal strings without performing filter processing, or only using limited filter processing, e.g., removal of frequency components higher than the Nyquist frequency. In these devices, when a focus detection calculation is carried out in a narrow focus detection area and a reliable defocus amount is not obtained, the contrast outside the focus detection area is determined and the focus detection calculation is either prevented from once again being carried out with a wide focus detection range based on the determined contrast, or the threshold value is made to be more restrictive, or other such steps. FIG. 6 is a block diagram that shows the structure of a second embodiment. The second embodiment is the same as the first embodiment, but with a mode setting circuit 5 added which selectively sets the wide mode and the spot mode. The mode setting circuit 5 comprises, for example, a switch or the like that is operated manually by the photographer. The focus detection optical system 1 and the image sensor 2 are the same as in the first embodiment. As in the first embodiment, the mathematical processing circuit 3 includes a filter processing circuit 3a, a calculation range setting circuit 3b, a threshold value setting circuit 3c, a maximum shift number setting circuit 3d, and a focus detection calculating circuit 3e. The filter processing circuit 3a is the same as that of the first embodiment. The contents of the calculation range setting circuit 3b differ from that of the first embodiment. FIGS. 7(a)-(c) show the calculation ranges set for s=2, s=4, and s=8, respectively. The solid line illustrates a wide mode, and the dashed line illustrates a spot mode. In the wide mode, when s=2, virtually the entire area is divided into 5 blocks. In this case, focus detection calculations are executed for each block, and the value that indicates the nearest distance, for example, is selected from among the maximum of 5 defocus amounts obtained. Similarly, when s=4 in the wide mode, the area is divided into 3 blocks. When s=8 in the wide mode, since, as described above, a wide calculation range is desirable, block division is not carried out, and virtually the entire area is taken as a single calculation area. When s=2, the calculation range of the spot mode is k=17 and r=30; when s=4, k=16 and r=27. When s=8, in spot mode 1, spot mode 3, and wide mode 1 (described hereafter), the calculation range is the same as that of the wide mode shown by the solid line in FIG. 7(c), and k=4 and r=31. The focus detection frame that is displayed on the finder screen of the camera in the spot mode is taken as the area that corresponds to the calculation range for the above-mentioned spot mode in which s=2, and will be referred to hereafter simply as the spot area. In spot mode 2 (described hereafter), when the contrast determining circuit 4 determines that there is a strong contrast outside the spot area, the range shown by the dotted line in FIG. 7(c) is used, for which k=13 and r=22. The threshold values E1 and G1 in Formula 6, which are set by the threshold value setting circuit 3c, differ according to the filter process and are taken as E1=Ea and G1=Ga when s=2, E1=Eb and G1=Gb when s=4, and E1=Ec and G1=Gc when s=8. These threshold values have the same relationship as described by Formula 9. In the third spot mode, when the contrast determining circuit 4 determines that there is a strong contrast outside the spot area, the threshold value for s=8 is taken to be a value that is more restrictive than the above-mentioned Ec. The maximum shift number lmax in Formula 1, which is set by the maximum shift number setting circuit 3d, differs according to the filter process. lmax=la when s=2, lmax=lb when s=4, and lmax=lc when s=8. These values have the same relationship as described by Formula 10. In the spot modes 2 and 3 when the contrast determining circuit 4 determines that there is a strong contrast outside the spot area, the maximum shift number for s=8 is taken to be a value that is smaller than the above-mentioned lc. The focus detection calculating circuit 3e carries out focus detection calculations according to Formulas 1-6 using the filter processing data Fa[i] and Fb[i] and calculates the focus adjustment condition of the photo lens 100, i.e., the defocus amount. In the wide mode, where s=2 or s=4, focus detection calculations are carried out for each block. The contrast determining circuit 4 calculates the contrast in each region to the left and right of the spot area of at least one of the filter processing data Fa[i] and Fb[i] that is obtained through the filter processing using s=2. The PP value is also calculated. The contrast determining circuit 4 then determines whether there is a strong contrast outside the spot area, based on the determined contrast and PP value. The calculation range in the spot mode for s=2 is from 17 to 30, and since the calculation range is the same as that on the first embodiment, the calculations and determinations are carried out through the same formulas as on the first embodiment. The operation of the second embodiment will be described using FIGS. 8-12. FIG. 8 is a flow chart that shows the entire operation of the second embodiment. In step S401, it is determined whether the wide mode is selected through the mode setting circuit 5. If the wide mode is selected, the program proceeds to step S402 and executes the wide mode. If the wide mode is not selected, the program proceeds to step S403 and executes the spot mode. FIG. 9 is a flow chart that shows the first operation of the spot mode in step S403 of FIG. 8. In this first operation, when it is determined through the contrast determining circuit 4 that there is a strong contrast outside the spot area, a focus detection calculation based on filter processing data for which low frequency components are extracted with s=8 is prevented. In step S501, output signal strings a[i] and b[i] are input from the image sensor 2. The program then proceeds to step S502 and calculates filter processing data Pa[i] and Pb[i] through Formula 7. In step S503, the value of s in Formula 8 is set to 2, and in step S504, filter processing data Fa[i] and Fb[i] are calculated by executing the filter calculation according to Formula 8. In step S505, the following values are set: initial value k0=17, final value r0=30, threshold value E1=Ea, threshold value G1=Ga, and the maximum shift number lmax=la. In step S506, the focus detection calculations of Formulas 1-6 are executed using the calculation range, threshold values, and maximum shift number set in the preceding step. In step S507, it is determined whether a reliable defocus amount is obtained. If a reliable defocus amount is obtained, the program advances to step S521, focus detection is determined to be possible, and the operation ends. Conversely, if a reliable defocus amount is not obtained, the program proceeds to step S508, calculates the contrast outside the spot area and the PP value through Formulas 11 and 12, respectively, and determines through Formula 13 whether a strong contrast exists outside the spot area. In step S509, the s value in Formula 8 is set to 4. The program proceeds to step S510 and calculates filter processing data Fa[i] and Fb[i] according to Formula 8. In step S511, the following values are set: initial value k0=16, final value r0=27, threshold value E1=Eb, threshold value G1=Gb, and the maximum shift number lmax=lb. In the following step S512, the focus detection calculations of Formulas 1-6 are executed using the calculation range, threshold values, and maximum shift number set in the preceding step. In step S513, it is determined whether a reliable defocus amount is obtained. If a reliable defocus amount is obtained, the program advances to step S521, focus detection is determined to be possible, and the operation ends. If a reliable defocus amount is not obtained, the program proceeds to step S514, and if it has been determined in step S508 that a strong contrast does not exist outside the spot area, the program proceeds to step S515. In step S515, the s value in Formula 8 is set to 8. The program proceeds to step S516 and calculates filter data Fa[i] and Fb[i] according to Formula 8. In step S517, the following values are set: initial value k0=4, final value r0=31, threshold value E1=Ec, threshold value G1=Gc, and the maximum shift number lmax=lc. In step S518, the focus detection calculations of Formulas 1-6 are executed using the calculation range, threshold values, and maximum shift number set in the preceding step. In step S519, it is determined whether a reliable defocus amount is obtained. If a reliable defocus amount is obtained, the program proceeds to step S521, focus detection is possible, and the operation ends. Conversely, if a reliable defocus amount is not obtained, the program proceeds to step S520, focus detection is determined to be impossible, and the operation ends. If it has been determined in step S514 that a strong contrast does exist outside the spot area, a focus detection calculation based on filter processing data for which even lower frequency components as extracted is prevented, the program advances to step S520, focus detection is determined to be impossible, and the operation ends. According to the first operation of the second embodiment, in the case of the subject patterns shown in FIG. 22 and FIG. 23, since a focus detection calculation based on filter processing data having low frequency components extracted is not carried out because strong contrast exists outside the spot area, focus detection becomes impossible. In the case of the subject patterns shown in FIG. 21 and FIG. 18, since a focus detection calculation is executed based on filter processing data having low frequency components extracted because strong contrast does not exist outside the spot area, focus detection becomes possible and a defocus amount can be determined. Steps S501-S504, S509, S510, S515, and S516 are operations of the filter processing circuit 3a; steps S505, S511, and S517 are operations of the calculation range setting circuit 3b, the threshold value setting circuit 3c, and the maximum shift number setting circuit 3d. Steps S508 and S514 are operations of the contrast determining circuit 4, and all other steps are operations of the focus detection calculating circuit 3e. FIG. 10 is a flow chart that shows a variation of the first operation of the spot mode (hereafter called the second operation of the spot mode) in step S403 of FIG. 8. In this second operation, when it is determined through the contrast determining circuit 4 that there is a strong contrast outside the spot area, the calculation range is narrowed in the focus detection calculation based on filter processing data having low frequency components extracted with s=8, the maximum shift number is decreased, and the shift range is narrowed. In step S601, output signal strings a[i] and b[i] are input from the image sensor 2. The program then proceeds to step S602 and calculates filter processing data Pa[i] and Pb[i] through Formula 7. In step S603, the value of s in Formula 8 is set to 2, and in step S604, filter processing data Fa[i] and Fb[i] are calculated according to Formula 8. In step S605, the following values are set: initial value k0=17, final value r0=30, threshold value E1=Ea, threshold value G1=Ga, and the maximum shift number lmax=la. In step S606, the focus detection calculations of Formulas 1-6 are executed using the calculation range, threshold values, and maximum shift number set in the preceding step. In step S607, it is determined whether a reliable defocus amount is obtained. If a reliable defocus amount is obtained, the program advances to step S622, focus detection is determined to be possible, and the operation ends. Conversely, if a reliable defocus amount is not obtained, the program proceeds to step S608, calculates the contrast outside the spot area and the PP value through Formulas 11 and 12, respectively, and determines through Formula 13 whether a strong contrast exists outside the spot area. In step S609, the s value in Formula 8 is set to 4, and in step S610, filter processing data Fa[i] and Fb[i] are calculated according to Formula 8. In step S611, the following values are set: initial value k0=16, final value r0=27, threshold value E1=Eb, threshold value G1=Gb, and the maximum shift number lmax=lb. In step S612, the focus detection calculations of Formulas 1-6 are executed using the calculation range, threshold values, and maximum shift number set in the preceding step. In step S613, it is determined whether a reliable defocus amount is obtained. If a reliable defocus amount is obtained, the program advances to step S622, focus detection is determined to be possible, and the operation ends. Conversely, if a reliable defocus amount is not obtained, the program proceeds to step S614 and sets the s value to 8. Next, in step S615, filter processing data Fa[i] and Fb[i] are calculated according to Formula 8. In step S616, if it is determined in step S608 that strong contrast does not exist outside the spot area, the program proceeds to step S617, in which a wide calculation range and a large maximum shift number are set; if it is determined that strong contrast does exist outside the spot area, the program proceeds to step S618, in which a narrow calculation range and a small maximum shift number are set. In step S617, the following values are set: initial value k0=4, final value r0=31, threshold value E1=Ec, threshold value G1=Gc, and the maximum shift number lmax=lc. In step S618, the following values are set: initial value k0=13, final value r0=22, threshold value E1=Ec, threshold value G1=Gc, and the maximum shift number lmax=lc/2. In step S619, the focus detection calculations of Formulas 1-6 are executed using the calculation range, threshold values, and maximum shift number set in step S617 or step S618. In step S620, it is determined whether a reliable defocus amount is obtained. If a reliable defocus amount is obtained, the program proceeds to step S622, focus detection is possible, and the operation ends. If a reliable defocus amount is not obtained, the program proceeds to step S621, focus detection is determined to be impossible, and the operation ends. According to this second operation, in the case of the subject patterns shown in FIG. 22(a) and FIG. 23 where strong contrast exists outside the spot area, a focus detection calculation based on filter processing data having low frequency components extracted is carried out with a narrow calculation range and a small maximum shift number. Specifically, with respect to the subject pattern shown in FIG. 22(a), focus detection is carried out for an area with no contrast since the calculation range is narrow. Therefore, focus detection becomes impossible. With regard to the subject pattern shown in FIG. 23, since a correlation amount is not calculated for a shift amount that will result in false focus, focus detection becomes impossible through the setting of a small maximum shift number. With respect to the subject patterns shown in FIG. 21(a) and FIG. 18(a), since strong contrast does not exist outside the spot area, a focus detection calculation based on filter processing data having low frequency components extracted is carried out with a wide calculation range and a large maximum shift number. Consequently, focus detection becomes possible and a defocus amount can be detected. In step S618, the maximum shift number was decreased to 1/2 of the normal value. However, the decrease in the maximum shift number is not limited to this value. Steps S601-S604, S609, S610, S614, and S615 are operations of the filter processing circuit 3a; steps S605, S611, S617, and S618 are operations of the calculation range setting circuit 3b, the threshold value setting circuit 3c, and the maximum shift number setting circuit 3d. Steps S608 and S616 are operations of the contrast determining circuit 4, and all other steps are operations of the focus detection calculating circuit 3e. FIG. 11 is a flow chart that shows another variation of the first operation of the spot mode (hereafter called the third operation of the spot mode) in step S403 of FIG. 8. In this third operation, when it is determined through the contrast determining circuit 4 that there is a strong contrast outside the spot area, the threshold values are made more restrictive for the focus detection calculation based on filter processing data having low frequency components extracted, the maximum shift number is decreased, and the shift range is narrowed. In step S701, output signal strings a[i] and b[i] are input from the image sensor 2. The program then proceeds to step S702 and calculates filter processing data Pa[i] and Pb[i] through Formula 7. In step S703, the value of s in Formula 8 is set to 2, and in step S704, filter processing data Fa[i] and Fb[i] are calculated according to Formula 8. In step S705, the following values are set: initial value k0=17, final value r0=30, threshold value E1=Ea, threshold value G1=Ga, and the maximum shift number lmax=la. In step S706, the focus detection calculations of Formulas 1-6 are executed using the calculation range, threshold values, and maximum shift number set in the preceding step. In step S707, it is determined whether a reliable defocus amount is obtained. If a reliable defocus amount is obtained, the program advances to step S722, focus detection is determined to be possible, and the operation ends. Conversely, if a reliable defocus amount is not obtained, the program proceeds to step S708, calculates the contrast outside the spot area and the PP value through Formula 11 and Formula 12, respectively, and determines through Formula 13 whether a strong contrast exists outside the spot area. In step S709, the s value in Formula 8 is set to 4, and in the following step S710, filter processing data Fa[i] and Fb[i] are calculated by executing the filter calculation according to Formula 8. In step S711, the following values are set: initial value k0=16, final value r0=27, threshold value E1=Eb, threshold value G1=Gb, and the maximum shift number lmax=lb. In step S712, the focus detection calculations of Formulas 1-6 are executed using the calculation range, threshold values, and maximum shift number set in the preceding step. In step S713, it is determined whether a reliable defocus amount is obtained. If a reliable defocus amount is obtained, the program advances to step S722, focus detection is determined to be possible, and the operation ends. Conversely, if a reliable defocus amount is not obtained, the program proceeds to step S714 and sets the s value to 8. In step S715, filter processing data Fa[i] and Fb[i] are calculated according to Formula 8. In step S716, if it is determined in step S708 that strong contrast does not exist outside the spot area, the program proceeds to step S717, in which a normal threshold value and a large maximum shift number are set; if it is determined that strong contrast does exist outside the spot area, the program proceeds to step S718, in which a restrictive threshold value and a small maximum shift number are set. In step S717, the following values are set: initial value k0=4, final value r0=31, threshold value E1=Ec, threshold value G1=Gc, and the maximum shift number lmax=lc. In step S718 the following values are set: initial value k0=4, final value r0=31, threshold value E1=2xEc, threshold value G1=Gc, and the maximum shift number lmax=lc/2. In step S719, the focus detection calculations of Formulas 1-6 are executed using the calculation range, threshold values, and maximum shift number set in step S717 or step S718. In step S720, it is determined whether a reliable defocus amount is obtained. If a reliable defocus amount is obtained, the program proceeds to step S722, focus detection is possible, and the operation ends. Conversely, if a reliable defocus amount is not obtained, the program proceeds to step S721, focus detection is determined to be impossible, and the operation ends. According to this third operation, in the case of the subject patterns shown in FIG. 22(a) and FIG. 23, a focus detection calculation based on filter processing data having low frequency components extracted is carried out with a restrictive threshold value and a small maximum shift number. With respect to FIG. 22(a), since the threshold value becomes restrictive, there is no reliability even though contrast exists in the calculation range, and focus detection becomes impossible. With respect to FIG. 23, since a correlation amount is not calculated for a shift amount that will result in false focus, focus detection becomes impossible through the setting of a small maximum shift number. In the case of the subject patterns shown in FIG. 21(a) and FIG. 18(a), since strong contrast does not exist outside the spot area, a focus detection calculation based on filter processing data having low frequency components extracted is carried out with a restrictive threshold value and a large maximum shift number, focus detection becomes possible, and a defocus amount can be detected. In step S718, only the threshold value E1 was set so as to be restrictive. However, the threshold value G1 may also be set so as to be restrictive. In addition, the threshold value was set to be twice the normal threshold value. However, the threshold value is not limited to this value. Furthermore, instead of using the numerical value E, the contrast for one of a pair of data may be calculated, and the evaluation may be carried out using this value. In addition, in the third operation, a focus detection calculation based on filter processing data for which low frequency components have been extracted with s=8 is carried out with a wide calculation range even if strong contrast exists outside the spot area. However, it is also acceptable to set a narrow calculation range, as in the second operation. Steps S701-S704, S709, S710, S714, and S715, are operations of the filter processing circuit 3a; steps S705, S711, S717, and S718 are operations of the calculation range setting circuit 3b, the threshold value setting circuit 3c, and the maximum shift number setting circuit 3d. Steps S708 and S716 are operations of the contrast determining circuit 4, and all other steps are operations of the focus detection calculating circuit 3e. It is obvious that while the first through third operations are disclosed as provided separately in a single camera, any two or all three operations may be combined in a single camera. FIG. 12 is a flow chart that shows the operation of the wide mode in step S402 of FIG. 8. In this wide mode operation, a determination is not executed by the contrast determining circuit 4, and the filter processing is switched until a reliable defocus amount is obtained. In step S801, output signal strings a[i] and b[i] are input from the image sensor 2. The program then proceeds to step S802 and calculates filter processing data Pa[i] and Pb[i] through Formula 7. In step S803, the value of s in Formula 8 is set to 2, and in step S804, filter processing data Fa[i] and Fb[i] are calculated according to Formula 8. In step S805, the area is divided into 5 blocks as shown in FIG. 7 (a), and the following values are set: threshold value E1=Ea, threshold value G1=Ga, and the maximum shift number lmax=la. In step S806, the focus detection calculations of Formulas 1-6 are executed using the 5 blocks, threshold values, and maximum shift number set in the preceding step. In step S807, it is determined whether there is a block for which a reliable defocus amount is obtained. If a block with a reliable defocus amount is obtained, the program advances to step S819, focus detection is determined to be possible, and the operation ends. If it is determined that there is no reliability in any of the blocks, the program proceeds to step S808 and sets the s value in Formula 8 to 4. In the following step S809, the filter processing data Fa[i] and Fb[i] are obtained according to Formula 8. In step S810, the area is divided into 3 blocks as shown in FIG. 7 (b), and the following values are set: threshold value E1=Eb, threshold value G1=Gb, and the maximum shift number lmax=lb. In step S811, the focus detection calculations of Formulas 1-6 are executed using the three blocks, threshold values, and maximum shift number set in the preceding step. In step S812, it is determined whether there is a block for which a reliable defocus amount is obtained. If a block with a reliable defocus amount is obtained, the program advances to step S819, focus detection is determined to be possible, and the operation ends. If it is determined that there is no reliability in any of the blocks, the program proceeds to step S813 and sets the s value in Formula 8 to be 8. In step S814, the filter data Fa[i] and Fb[i] are obtained by executing the filter calculation according to Formula 8. In step S815, the following values are set: initial value k0=4, final value r0=31, threshold value E1=Ec, threshold value G1=Gc, and the maximum shift number lmax=lc. In step S816, the focus detection calculations of Formulas 1-6 are executed using the calculation range, threshold values, and maximum shift number set in the preceding step. In step S817, it is determined whether a reliable defocus amount is obtained. If a reliable defocus amount is obtained, the program proceeds to step S819, focus detection is possible, and the operation ends. Conversely, if a reliable defocus amount is not obtained, the program proceeds to step S818, focus detection is determined to be impossible, and the operation ends. Steps S801-S804, S808, S809, S813, and S814 are operations of the filter processing circuit 3a; steps S805, S810, and S815 are operations of the calculation range setting circuit 3b, the threshold value setting circuit 3c, and the maximum shift number setting circuit 3d. All other steps are operations of the focus detection calculating circuit 3e. In the above-mentioned wide mode, no determinations are made through the contrast determining circuit 4. However, the contrast determining circuit 4 may be used to determine the contrast outside the spot area, in the same manner as the spot mode, and to prevent focus detection calculations that are based on filter processing data with s=8 when a strong contrast exists, or else to carry out the focus detection calculations with decreased maximum shift numbers and restrictive threshold values. By taking these measures, the possibility of false focus will be reduced. In the illustrated embodiments, the focus detection controller 3 is implemented as a single special purpose integrated circuit (e.g., ASIC) having a main or central processor section for overall, system-level control, and separate sections dedicated to performing various different specific computations, functions and other processes under control of the central processor section. It will be appreciated by those skilled in the art that the controller can also be implemented using a plurality of separate dedicated or programmable integrated or other electronic circuits or devices (e.g., hardwired electronic or logic circuits such as discrete element circuits, or programmable logic devices such as PLDs, PLAs, PALs or the like). The controller can also be implemented using a suitably programmed general purpose computer, e.g., a microprocessor, microcontroller or other processor device (CPU or MPU), either alone or in conjunction with one or more peripheral (e.g., integrated circuit) data and signal processing devices. In general, any device or assembly of devices on which a finite state machine capable of implementing the flowcharts shown in FIGS. 3-5 and 8-12 can be used as the controller. While this invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, the preferred embodiments of the invention as set forth herein are intended to be illustrative, not limiting. Various changes may be made without departing from the scope of the invention as defined in the following claims.

A focus detection device includes a pair of photoelectric converting element arrays that output a pair of signal strings and a focus detection optical system, including a photo lens, that conducts a pair of light rays from a subject to the pair of photoelectric converting element arrays. A filter extracts a pair of signal strings having a predetermined frequency component from the pair of signal strings outputted by the photoelectric converting element arrays. A calculation range setting device sets a calculation range of signals of the pair of extracted signal strings, and a focus detection calculating device calculates a focus adjustment condition for the photo lens based on the signals of the pair of extracted signal strings in the calculation range. A contrast calculation device calculates the contrasts in areas outside the calculation range based on the signals of the pair of extracted signal strings excluded from the calculation range, wherein the operation of the focus detection calculating device is dependent upon the calculated contrasts. When the calculated contrast exceeds a predetermined value, focus detection calculations based on a pair of signal strings with lower frequency components are not carried out, or else the shift range for correlation calculations is narrowed, or else the threshold values for reliability determination are changed and the reliability determination standard is made to be more restrictive, or else the focus detection calculation range is narrowed.

REFERENCE TO RELATED APPLICATION [0001] The present application claims the benefit of U.S. Provisional Patent Application No. 60/586,410, filed Jul. 9, 2004, whose disclosure is hereby incorporated by reference in its entirety into the present disclosure. FIELD OF THE INVENTION [0002] The present invention relates generally to technical analysis. More particularly, the present invention relates to a method of timeseries markup and annotation in technical analysis of stock investments and an automated system for assisting investors in deciding whether to buy or sell certain investments, and more particularly to such a system which automatically analyzes investment timeseries patterns to determine whether certain buy or sell indicators are present. BACKGROUND OF THE INVENTION [0003] Technical financial analysis, as opposed to fundamental analysis, uses the timeseries of prices of historical trades, the timeseries of trading volumes, or other measures of a stock, or of a market as a whole, to predict the future direction of the stock or market and to identify turning points, trends, or other information. Recognizing patterns in the timeseries is greatly enhanced by efficient pattern recognition and automated signaling or annotation of the timeseries. [0004] Many traders utilize trading strategies and make decisions based on technical analysis. Their strategies hold that publicly available technical data of an investment—such as the open, high, low, and close prices, daily volumes, trade price and size, and bid/ask prices and bid/ask sizes—contain information that can predict the future price movements of the investment and that analyzing such timeseries data can enable them to achieve superior returns on their investment decisions. [0005] Over the course of the past 70 years, technical analysts have developed a wide variety of indicators based on timeseries data for stocks. For example, moving averages (MA), relative strength indexes (RSI), moving average convergence and divergence (MACD), Bollinger bands, K/D stochastic analysis, and various indexes are among the popular calculated indicators used to characterize individual stocks. Technical analysts and traders believe that certain investment indicator patterns provide early signals of buy and sell opportunities. Today computers are routinely used to plot investment timeseries with share prices and volumes and various calculated indicators, and the indicator signals and annotations pertaining to the investments plotted are used by the traders to implement a trading strategy. [0006] Technical trading can only succeed in the long run if it is possible to accurately identify buy or sell patterns from the timeseries data, and to detect them early enough so that the appropriate trades can be undertaken. Finding a pattern after the trading opportunity has passed and is no longer valid has no utility at all. Finding a pattern late—after other traders in the market have recognized it and reacted to it, or so late in the context of the stock's daily market volume and liquidity such that it is impossible to find counterparties to execute trades in the size necessary to achieve one's desired position in the stock—also has little value. [0007] A number of terms of art are used in the present specification. An indicator is a calculation based on stock price and/or volume that produces a number in the same unit as price. An example of an indicator is the moving average of a stock price. An oscillator is a calculation based on stock price and/or volume that produces a number within a range. An example of an oscillator is the moving average convergence/divergence (MACD). [0008] The terms “technical event” and “fundamental event” are terms denoting points such as the price crossing the moving average or the MACD crossing the zero-line. A technical event or fundamental event occurs at a specific point in time. Trading signals associated with most indicators and most oscillators can be represented as technical events. A technical event, as used herein, is the point in time where a share price has interacted with an indicator or a price pattern or an oscillator has crossed a threshold. Fundamental events are the point in time where a share price has interacted with a price value computed from company accounting data, from data pertaining to the valuation of the company's assets and liabilities and financial leverage, and/or other economic data. [0009] A price pattern is a classification of a timeseries segment that indicates changes in the supply and demand for a stock, which is associated with a significant rise or fall in share price. A reversal pattern is a type of price pattern that indicates a change in the direction of a price trend. If prices are trending down, then a reversal pattern is bullish, since its appearance is believed to indicate prices will move higher. Conversely, if prices are trending up, then a reversal pattern will be bearish. Price patterns have been described by a number of authors, including Edwards and Magee. [0010] Price patterns that predict or denote latent fundamental events are particularly valuable to traders. Stochastic volatility (SV) models infer changes in a company's financial leverage that have not yet materialized but are nonetheless revealed by subtle shifts in investor sentiment affecting trades by certain insiders and analysts who have close and recent knowledge of the company's situation, reflected in share price timeseries data. [0011] Two alternative SV specifications co-exist in the literature. One is the conventional Euler approximation to the continuous-time SV model with leverage effect. The other is the discrete-time SV model of Jacquier. Using a Gaussian nonlinear state space form with uncorrelated measurement and jump transition errors, it is possible to interpret the leverage effect in the conventional model. The SP500, Russell3000, and other portfolios of highly liquid stocks show strong evidence of the expected leverage effect. However, thinly-traded small- and mid-cap stocks show only a small leverage effect or, in some cases, paradoxical inverse leverage. The natural log of the period-to-period ratio of the estimated stochastic volatility σ v appears to be a robust leading indicator of emergent investor sentiment with regard to structural issues that affect a particular firm or sector. [0012] In sectors represented by firms with single product lines that are still in development (pre-commercialization), such as biotech and early-stage pharma/biopharma companies, there tends to be scanty information regarding factors that predict the future approval, market penetration, and growth of the firms. Newly emerging information concerning a class of therapeutic compounds, such as convincing efficacy results or clearer understanding of the mechanism of action, can lead to a groundswell of positive opinion regarding the future of the entire class of compounds. Likewise, in highly-regulated sectors such as healthcare services, the outcome of anticipated regulation or coverages and reimbursement decisions is highly uncertain, and accurate information that bears on the likelihood of various outcomes is not regularly or frequently accessible to the majority of investors. However, once the consideration of certain evidence by the AHRQ-CMS MCAC committee becomes known, prevailing opinion rapidly converges toward the most probable regulatory decision. [0013] Insofar as the equities of such firms show excess volatility (noise) compared to firms of similar size in industries that are not subject to as much uncertainty, finding a reliable signal of emerging investor sentiment is difficult. In this connection, stochastic volatility (SV) models have gained much attention both in the option pricing literature and financial econometrics literature (Andersen (1999), Engle (1993), Fouque (2000), Harvey (1996), Hull & White (1987); see Shephard (1996) for a review of SV models and their applications). [0014] The relationship between volatility and price/return has long been a subject of study. Conventional wisdom holds that when there is bad news (which decreases the price and indirectly increases a credit's debt-to-equity ratio, i.e., financial leverage), the credit becomes riskier. The event tends to be associated with an increase in future expected volatility of the credit's common shares. A premium is attached to the implied future expected volatility and this is reflected in short-term share price. As a result, the leverage effect must correspond to a negative correlation between volatility and price/return. Christie (1982) found empirical evidence of such a leverage effect. By computing volatility from end-of-day data, Christie postulated a parametric form for the volatility—return relationship, enabling a simple test for leverage effect. [0015] In the option pricing literature, the asymmetric SV model (ASV) is often formulated in terms of stochastic differential equations. One widely-used ASV model specifies the following equations for the logarithmic asset price s(t) and the corresponding volatility: { ds ⁢   ⁢ ( t ) = σ ⁢   ⁢ ( t ) ⁢   ⁢ d ⁢   ⁢ B 1 ⁡ ( t ) , d ⁢   ⁢ ln ⁢   ⁢ σ 2 ⁡ ( t ) = α + βlnσ 2 ⁡ ( t ) ⁢ dt + σ υ ⁢ d ⁢   ⁢ B 2 ⁡ ( t ) , Eq ⁢ .1 where B 1 (t) and B 2 (t) are two Brownian motions, corr(dB 1 (t), dB 2 (t))=ρ, and s(t)=ln(P(t)) with P(t) being the share price of the underlying. When ρ<0 we have the leverage effect. [0016] In the empirical literature the above model is often discretized to facilitate estimation and to reflect the practical realities of the timeseries data that are available. The Euler-Maruyama approximation leads to our proposed discrete-time ASV model: { X t = σ t ⁢ u t , ln ⁢   ⁢ σ t + 1 2 = α + ϕlnσ t 2 + σ υ , v t + 1 , Eq ⁢ .2 where X t =s(t+1)−s(t) is a continuously-compounded return, u t =B 1 (t+1)−B 1 (t), v t+1 =B 2 (t+1)−B 2 (t), φ=1+β. Hence, u t and v t are iid N(0, 1) and corr(u t , v t+1 )=ρ. This ASV model has been previously studied by a quasi maximum likelihood method in Harvey and Shephard (1996) and by MCMC in Meyer and Yu (2000). [0017] To understand the linkage of the alternative ASV specifications to the leverage effect, it is convenient to adopt a Gaussian nonlinear state space form with uncorrelated measurement and transition equation errors. To do this, we use the identity w t+1 =(v t+1 −ρu t )/√(1−ρ 2 ) and rewrite Eq. (2) as: { X t = σ t ⁢ u t , ln ⁢   ⁢ σ t + 1 2 = α + ϕlnσ t 2 + ρσ υ , σ t - 1 ⁢ X t + σ υ ⁢ 1 - ρ 2 ⁢ w t + 1 , Eq ⁢ .3 where w t ˜N(0, 1). This is a linear function in X t which implies that, if ρ<0 and everything else is held constant, a fall in the stock price/return leads to an increase of E(ln σ t+1 2 |X t ). This is intuitively consistent with the normal leverage effect we expect in an efficient market. [0018] Similarly, for the Jacquier ASV in nonlinear Gaussian state space form we have: { X t = σ t ⁢ u t , ln ⁢   ⁢ σ t + 1 2 = α + ϕlnσ t 2 + ρσ υ , σ t - 1 ⁢ X t + 1 + σ υ ⁢ 1 - ρ 2 ⁢ w t + 1 . Eq ⁢ .4 Because σ t+1 appears on both sides of the equation, it is impossible to obtain the relationship between E(ln σ t+1 2 |X t ) and X t in analytical form. Therefore, it is not clear how to interpret the leverage effect in Jacquier's ASV model specification. REFERENCES [0000] Andersen T, Chung H, Sorensen B. Efficient method of moments estimation of a stochastic volatility model: A Monte Carlo study. J Econometr 1999; 91:61-87. Chib S, Nardari F, Shephard N. Markov Chain Monte Carlo methods and stochastic volatility models. J Econometr 2002; 108:281-316. Christie A A. The stochastic behavior of common stock variances. J Fin Econ 1982; 10:407-32. Edwards R D, Magee J. Technical Analysis of Stock Trends . St. Lucie Press, 1998. Engle R, Ng V. Measuring and testing the impact of news in volatility. J Fin 1993; 43:1749-78. Eraker B, Johannes M, Polson N. The impact of jumps in volatility and returns. J Fin 2003; 53:1269-300. Fouque J-P, Papanicolaou G, Sircar K R. Derivatives in Financial Markets with Stochastic Volatility . Cambridge: Cambridge Univ Press, 2000. Harvey A C, Shephard N. The estimation of an asymmetric stochastic volatility model for asset returns. J Bus Econ Stat 1996; 14:429-34. Hull J, White A. The pricing of options on assets with stochastic volatilities. J Fin 1987; 42:281-300. Jacquier E, N. G. Polson N G, Rossi P E. Bayesian analysis of stochastic volatility models. J Bus Econ Stat 1994; 12:371-89. Kim S, Shephard N, Chib S. Stochastic volatility: Likelihood inference and comparison with ARCH models. Rev Econ Stud 1998; 65:361-93. Kitagawa G. Monte Carlo filter and smoother for Gaussian nonlinear state space models. J Comput Graph Stat 1996; 5:1-25. Meyer R, Yu J. BUGS for a Bayesian analysis of stochastic volatility models. Econometr J 2000; 3:198-215. Rogers E M. Diffusion of Innovations. 5e. New York: Free Press, 2003. Shephard N. “Statistical aspects of ARCH and stochastic volatility.” In Cox DR, Hinkley D V, Barndorff-Nielson O E. (eds), Time Series Models in Econometrics, Finance and Other Fields , pp. 1-67. London: Chapman & Hall, 1996. Shleifer A. Inefficient Markets: Introduction to Behavioral Finance . Oxford: Oxford Univ Press, 2000. SUMMARY [0035] What is desired, therefore, is an automated system for assisting investors in deciding whether to buy or sell investments which automatically analyzes investments to determine if leading buy or sell indicators are present; which is capable of identifying buy or sell indicators well in advance of a technical event or fundamental event so that they can be acted upon while they are still valid and trades can be executed in the sizes desired; and which automatically analyzes investment timeseries to take trading decisions about investments. [0036] Accordingly, it is an object of the present invention to provide an automated system for assisting investors in deciding whether to buy or sell investments, which automatically analyzes investments to determine if buy or sell indicators are present. [0037] A further object of the present invention is to provide a system having the above characteristics and which is capable of quickly identifying buy or sell indicators so that they can be acted upon while they are still valid and while there is time sufficient for the trader to adjust his or her positions in the stock before other traders in the market react or before publication of news related to the fundamental event predicted by the ASV indicator impairs the stock's liquidity. [0038] These and other objects of the present invention are achieved by provision of an automated investment timeseries pattern search system, which includes a computer, a information database accessible by the computer having historical information for a plurality of investments stored thereon, a connection to a supply of real-time data, the data comprising real-time data relating to a plurality of investments, and a templates database accessible by the computer having a plurality of templates stored thereon. Software executing on the computer generates an investment chart for the stock or stocks to be examined based upon the historical information and the real-time data relating to the stock or stocks to be examined. Software executing on the computer then performs ASV analysis on the stock timeseries to determine if an ASV pattern exists in the timeseries. The present invention utilizes the asymmetric stochastic volatility timeseries to reliably predict investor sentiment trajectories. [0039] In accordance with the invention, a method and system mitigating the limitations enumerated above and suitable for a stock investment signaling procedure is provided. It is an object of the present invention to mitigate at least one disadvantage of previous methods for technical analysis of stocks. It is a particular object of the present invention to provide a method for generating timeseries markup and directly annotating a timeseries based on categorized incipient fundamental and technical events and recognized patterns in timeseries of financial data, such as stock prices. [0040] According to a first aspect, there is provided a method for generating markup classifications for annotating a chart of timeseries data. A volatility feature set of technical event data related to the timeseries data is stored in a database. The volatility feature set includes identification of ASV inflection points in the timeseries data, pattern recognition data derived from the identified ASV inflection points, the identified ASV inflection points and the timeseries data. The method comprises receiving, from a client, a request for markup information related to a stock or a plurality of stocks. Price and volume timeseries for the stock or stocks are downloaded, ASV calculations are performed, and features associated with the stock are then selected from the volatility feature set. Markup tags are then determined in accordance with the selected features, and the markup tags are assembled, in accordance with a markup format, to generate a markup annotation for the event. The markup annotation contains the requested markup information. The recommendation contained in the markup annotation is then sent to the client. [0041] In a further embodiment, the method includes displaying the timeseries as a chart at the client location, and annotating the chart in accordance with the markup information. The method can also include analyzing and manipulating the markup information at the client. The client can also specify a desired format for the markup information in the initial request. Preferably, the markup information is initially provided as an XML block, and then transformed, if desired, into any other desired format, such as HTML. Typically the features are also selected in accordance with the request. [0042] In a further aspect, the present invention provides a method for generating markup for annotating timeseries data having an associated volatility feature set as described above. The method comprises selecting features associated with an event from the volatility feature set; determining markup tags in accordance with the selected features; and assembling the markup tags, in accordance with a markup format, to generate a markup annotation for the event. [0043] Preferably, software executing on the computer pre-screens the historical information and the real-time data relating to the investment to be examined to determine whether the investment to be examined meets a threshold value for liquidity, and the software executing on the computer performs the ASV analysis only if the investment to be examined meets the threshold value for liquidity. Preferably, the investment to be examined is determined to meet the threshold value for liquidity if both average daily trading volumes and average daily prices for the investment to be determined meet a threshold value. Most preferably, the investment to be examined is determined to meet the threshold value for liquidity if the current day's trading volume is higher than average daily trading volumes. [0044] Preferably, the system also includes software executing on the computer for, if it is determined that a pattern exists in the stock timeseries, generating and transmitting to a user an indication that an actionable ASV pattern has been detected. [0045] Following Meyer and Yu (2000), our proposed ASV model and Jacquier's ASV model can be written, respectively, as: h t + 1 ❘ h t , α , ϕ , σ υ 2 ∼ N ⁡ ( α + ϕ ⁢   ⁢ h t , σ υ 2 ) , X t ❘ h t + 1 , h t , α , ϕ , σ υ 2 , ρ ∼ N ⁡ ( ρ σ υ ⁢ ⅇ h t / 2 ⁡ ( h t + 1 - α - ϕ ⁢   ⁢ h t ) , ⅇ h t ⁡ ( 1 - ρ 2 ) ) , ⁢ ⁢ and Eq ⁢ .5 h t ❘ h t - 1 , α , ϕ t , σ υ 2 ∼ N ⁡ ( α + ϕ ⁢   ⁢ h t - 1 , σ υ 2 ) , X t ❘ h t , h t - 1 , α , ϕ , σ υ 2 , ρ ∼ N ⁡ ( ρ σ υ ⁢ ⅇ h t / 2 ⁡ ( h t - α - ϕ ⁢   ⁢ h t - 1 ) , ⅇ h t ⁡ ( 1 - ρ 2 ) ) , Eq ⁢ .6 where h t =ln σ t 2 . These representations permit straightforward Bayesian MCMC parameter estimation using BUGS (http://www.mrc-bsu.cam.ac.uk/bugs/winbugs/contents.shtml) software. [0046] Regarding the prior distributions, for the parameters φ and σ v 2 the prior specifications of Kim, Shephard and Chib (1998) are effective in one embodiment: σ v 2 ˜Inverse-Gamma (2.5, 0.025), which has a mean of 0.167 and a standard deviation of 0.024; φ*˜Beta (20, 1.5), which has a mean of 0.167 and a standard deviation of 0.86 and 0.11, where φ*=(φ+1)/2. Furthermore, following Meyer and Yu (2000) in one embodiment it is satisfactory to take μ˜N(0, 25), where μ=α/(1−φ). For the MCMC initialization, the leverage correlation parameter ρ is assumed to be uniformly distributed between −1 and 1 (perfect a priori ignorance of leverage effect distribution). [0047] Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures. DESCRIPTION OF DRAWINGS [0048] Embodiments of the present invention will now be described, by way of example only, with reference to the attached figures, wherein: [0049] FIG. 1 is a block diagram of a computing system on which the preferred embodiment can be implemented; [0050] FIG. 2 is a flow chart of the overall steps carried out in the preferred embodiment; [0051] FIG. 3 is a block diagram of a system according to the preferred embodiment; [0052] FIG. 4 is a timeseries chart annotated according to the preferred embodiment; [0053] FIG. 5 is a timeseries chart annotated according to a sample XML markup annotation contained herein; and [0054] FIG. 6 is a plot of data used for back-testing an example stock. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT [0055] A preferred embodiment of the present invention will be set forth in detail with reference to the drawings. [0056] In the preferred embodiment as shown in FIG. 1 , the system 100 is comprised of a computer 102 , which, as is well-known to those skilled in the art is comprised, among other things, of a processor, memory and mass storage. The computer may also be networked to take advantage of other resources 103 on a local or wide area network or the Internet (collectively identified as 104 ). In addition, the computer 102 can interface with an investment trader through a keyboard 106 , mouse 108 , and display device 110 . The computer 102 may take the form of remote or wireless devices that can perform computations or receive investment signals from other computers or system practicing the present invention and the display device can take the form of a remote device, such as a personal digital assistant, pager or cell-phone (collectively shown as 112 ) with a visual, audio or tactile capabilities to communicate the investment signals. The computer executes the steps described herein to practice the present invention, and a display device, which may be separate from the computer, presents the results to the investment trader. [0057] Alternative embodiments of the present invention may also include transmitters to send information to the investment trader to request information and receivers to receive information back from the investment trader in accordance with the present invention. Overall Steps (explained with reference to FIG. 2 ) [0000] The following steps describe one aspect of practicing the present invention, beginning with step 202 : [0058] Step 204 : Define the ASV rule that can be coded to produce from published information, a sequence of buy and sell signals for every security in a given universe. Further define, in step 206 , a set of time-scales for investment horizons to which the rules for each strategy can be adapted in order to produce buy and sell signals for every security in a given universe over those time-scales. [0059] In step 208 , define a method of scoring the strategy's usefulness, for a time-scale, as applied to every security in a given investment universe, as well as scoring the aggregate usefulness of the strategy over all the securities in the given investment universe in step 210 . Further define a method of presenting that information for each security, and of comparing that information among the securities in the given investment universe, in step 212 . [0060] In step 214 , define a method of scoring every security in the given universe according to the buy and sell signals given by the ASV strategy for a time-scale, in conjunction with published information such as the security's price behavior. Further define a method of presenting that information for each security, and of comparing that information among the securities in the given investment universe. [0061] With these definitions in place, the system will generate the following: 1. For all securities in the system, scores for the usefulness of the ASV strategy over every time-scale, as well as the aggregate scores for these categories. 2. For all securities in the system, scores for securities according to the ASV strategy over every time-scale. [0064] With these definitions in place, users can proceed as follows: 1. Select a universe of securities (step 216 ). 2. Select a time-scale (step 218 ). 3. Compare between securities the ASV strategy's usefulness at that time-scale (step 220 ). 4. Compare between securities their scores given by the strategy (step 222 ). [0069] When the user is finished, as determined in step 224 , the process ends in step 226 . [0000] Setting Time-Scales, Measuring Performance Results [0000] 1. Steps will now be described in more detail: i. The steps for applying an ASV investment strategy to a universe of securities to generate buy and sell signals for every security in the universe are as follows: a. Buy and Sell Signals [0072] A buy signal is a signal to purchase the security. A buy signal remains in effect until it is reversed by a sell signal, so that as far as the strategy is concerned, a security with a buy signal is bought and held until the strategy steps emits a sell signal for the security. A sell signal is a signal to sell the security. A sell signal remains in effect until it is reversed by a buy signal, so that as far as the strategy is concerned, a security with a sell signal is sold and not held until the steps emits a buy signal for the security. [0000] b. Frequency of Updates to the Buy and Sell Signals [0073] The steps for a strategy can update buy and sell signals at any frequency. For instance, the steps for a strategy can be run to update the latest buy and sell signals for each security in the universe per day, per week and so on. [0000] c. Time-Scales for the Buy and Sell Signals [0074] Investment horizons vary according to individual investors. In order to provide buy and sell signals for groups of investors with shorter and longer investment horizons, the steps for a strategy generate separate sets of buy and sell signals for the securities in the universe according to shorter or longer time-scales. 1) A statistically meaningful sample size is needed to evaluate the performance of an ASV strategy's buy and sell signals according to the confidence interval for results that is required. Sample sizes less than 70 give confidence intervals that would be too large for many investors. This gives minimum time-scales of 70 days for daily signals, and 70 weeks for weekly signals, and so on. 2) The data measurements input for a strategy are adjusted to provide a sets of buy and sell signals for securities in the universe for each time-scale. The set of buy and sell signals that the strategy generates for each security in the universe by using data measurements designed to give signals for a minutely time-scale is called the set of minutely signals for the strategy. The set of buy and sell signals that the strategy generates for each security in the universe by using data measurements designed to give signals for a weekly time-scale is called the set of weekly signals for the strategy, and so on. 3) Because the data measurements used by the strategy are not the same for each time-scale, the sets of buy and sell signals generated by the strategy for shorter and longer time-scales are likely to differ. d. Sampling Intervals to Create Histories of Buy and Sell Signals Over a Period 1) For a given time-scale, the strategy generates buy and sell signals for each security in the universe. Histories of buy and sell signals are created by recording the signals at intervals over a period. The sampling intervals vary according to the time-scale for which the signals are generated. For example: a) Daily. A set of daily signals is created by sampling the signals at the daily market close. If done for 120 days, this will create a history of daily buy and sell signals for the period with 120 data points for each security. b) Weekly. A set of weekly signals is created by sampling the signals at the weekly market close. If done for 120 weeks, this will create a history of weekly buy and sell signals for the period with 120 data points for each security. 2) The interval at which signals for a time-scale are sampled in order to create histories of signals can be much longer than the frequency at which the signals are updated. For instance, although signals calculated for a daily time-scale can be updated each minute, it can be that only the signal at the daily close is taken into account for the history of the daily buy and sell signals. 3) The steps can be applied to historical data sets to generate histories of buy and sell signals as they would have appeared in the past. In this way, buy and sell signal histories of any length for any time-scale can be generated, covering any period for which there is data. ii. Measuring the Performance Results. These steps will generate for every security in the universe the performance statistics that result from investing over a period according to the strategy's buy and sell signals at a given time-scale. a. Periods [0084] The periods over which the performance is calculated for the strategy's buy and sell signals correspond to the time-scale of the signals. The histories of buy and sell signals for the period will contain a number of data points that is statistically meaningful according to the confidence interval for results that is required. For example, choosing a sample size of 120 data points would measure performances over periods of 24 weeks for daily signals, and more than two years for weekly signals. [0000] b. Trading Costs [0085] Performance statistics for the strategy are adjusted for trading costs per signal. Average trading costs across markets, or average trading costs within markets are used to reflect trading costs in performance results for the strategy. For example, a cost of 1% per buy and sell signal can be used. [0000] c. Benchmarks [0086] In order to obtain a comparative measure for the outcome of having followed a strategy's buy and sell signals for a security, the present invention will compare the performance over the period from following the signals to a benchmark performance for the security over the period. [0000] 1) Absolute Benchmarks [0000] i) Absolute Return Benchmark. In this case, the strategy's performance for the security is measured against a benchmark performance of 0% for the security. If the strategy generates a positive return over the period, it will show a positive performance compared to benchmark. If the strategy generates a negative return over the period it will show a negative performance compared to benchmark. Comparing the strategy's performance to this benchmark will tell the user whether the strategy made money in the security, whatever the performance of the security over the period. ii) Buy and Hold Return Benchmark. In this case, the strategy's performance is measured against the return from holding the security throughout the period. If the strategy generates a higher return by trading the security during the period than was had by holding the security during the period, it will show a positive performance compared to benchmark. Otherwise the strategy will show a negative performance compared to benchmark. Comparing the strategy's performance to this benchmark will tell the user whether the strategy made a higher return by not purchasing or trading the security than by holding the security over the period. 2) Relative Benchmarks i) Market Return Benchmark. In this case, the strategy's performance for the security is measured against a market index return over the period. If the strategy generates a higher return by trading the security during the period than was had by holding the market index during the period, it will show a positive performance compared to benchmark. Otherwise the strategy will show a negative performance compared to benchmark. Comparing the strategy's performance to this benchmark will tell the user whether the strategy made a higher return by trading the security than by holding the market index over the period. ii) Buy and Hold Relative Return Benchmark. In this case, the strategy's performance is measured against the security's return relative to the market index from holding the security throughout the period. If the strategy generates a higher return relative to the market index by trading the security during the period than was had by holding the security during the period, it will show a positive performance compared to benchmark. Otherwise the strategy will show a negative performance compared to benchmark. Comparing the strategy's performance to this benchmark will tell the user whether the strategy made a higher return relative to the market by trading in and out of the security than by holding the security over the period. a) The calculations for this benchmark are identical to those for the Buy and Hold Return benchmark except that the security's price history over the period is divided by the market index's price history over the period. b) The market index can be any index—a global, regional or country index, a sector or industry index, a large capitalization or small capitalization index, etc. [0093] Generally, the present invention provides a method for generating chart markup and automatically annotating a chart in the technical analysis of a timeseries. [0094] Generally, the ASV technique determines the ASV inflection, or turning points, and categorizes them according to their bearing upon likely future price movements, while associating time, or lag, information with each identified point. First, the timeseries is defined, usually by taking some point of interest from a larger series (henceforth called the “end point”) and a suitable number of prior values to define a search period. The lag of each point with respect to the end point is determined, i.e. the end point has lag=0. [0095] Once the ASV inflection points have been identified and categorized, and the desired formations recognized from the ASV inflection point data, the quality of the recognized patterns can be rated. The volatility feature set includes ASV formation type, ASV inflection points defining the formation, dates associated with each ASV inflection point, and trade volumes. Further features, also part of the volatility feature set, can be calculated from this information, depending on the formation type. These calculated, or derived, values can include trend height, trend duration, threshold price, pattern height, symmetry, and statistical measures of formation quality, well known to those of skill in the art. [0096] Once a pattern has been recognized and the volatility feature set stored, the chart markup and annotation method of the present invention can be applied. Generally, the timeseries, or a portion thereof containing the recognized ASV formation, is displayed as a graphical timeseries chart. The timeseries can be displayed as an OHLC, candlestick or bar chart, as desired. Since the ASV inflection point data set contains time data, the ASV inflection points can be easily identified and marked on the displayed timeseries. Lines are then drawn between the ASV inflection points to graphically display the recognized pattern, and the ASV inflection points are labeled with the relevant spatial and/or time data, typically with their associated price and/or date. [0097] FIG. 3 is a block diagram of a system 300 , according to an embodiment of the present invention. System 300 includes a number of interconnected modules, typically embodied as software modules. Market data module 302 provides market data, for example, daily stock market information such as high price, low price, open price, close price, volume, open interest and tick data values for stocks. The market data can be downloaded on a continuous, real-time basis directly from stock market providers 301 , or can be sampled on a periodic basis, such as inter-day, daily or weekly. The market data can include data for a whole market, or data related to certain identified stocks. Market data module 302 feeds the market data to ASV module 308 , which identifies candidate patterns at different window sizes. The identified candidate formations are written into a database 320 for further analysis. The ASV module 308 can also generate chart markup and annotation. The ASV module 308 also feeds the characterization module 322 . [0098] The calculation engine 304 computes, from the timeseries data, values, such as simple log-ratios of serial price values, and writes the calculated values into the database 320 . These are technical analysis calculations that are used to initialize the ASV module 308 . [0099] Candidate patterns recognized by the ASV module 308 can also be ranked by human experts as a periodic training activity. In this case, candidate patterns are shown to human experts who then rank or rate this information based on their experience and back-test the results against historical performance of selected stocks and fundamental events in the companies' histories. [0100] The characterization engine 322 computes various characteristics for every candidate pattern found by the ASV module 308 . The characterization engine 322 reads candidate patterns, computes ASV pattern and event characteristics and write results back to database 320 . [0101] Patterns and event information, and characteristics are passed to filter 324 that screens output based on defined criteria. A filter 324 is defined for each user of the system 300 . Filters 324 restrict the patterns passed out of the system 300 to ensure that patterns delivered meet certain minimum thresholds. For example, a filter may specify that only patterns having LN DELSIG σ v exceeding a certain value are to be passed. [0102] The final result of the ASV analysis is the technical event annotation related to the timeseries data, which is stored in the database and signaled to the user via an API module 340 and a client application 360 . The Markov Chain Monte Carlo tables are generated by standard Bayes Gibbs Sampler methods, and in the preferred embodiment are so calculated using WinBUGS™ software. [0103] FIG. 4 shows a timeseries chart annotated according to the embodiment disclosed above. FIG. 5 shows a timeseries chart annotated according to a sample XML markup annotation. [0104] In the preferred embodiment it is sufficient to use a burn-in period of 10,000 iterations to allow mixing and stabilization of the sampling, discard the burn-in sampled values of the parameters, reset the parameters' counters, then perform a follow-up of 50,000 iterations. In one embodiment, we initialize the Win BUGS MCMC Gibbs sampler by setting μ=0, φ=0.98, σ v 2 =0.025, and ρ=−0.40. This appears to work well, both for equities and portfolios that have large daily volume and large leverage correlation (ρ<−0.5) as well as for equities that have small leverage effect or a paradoxical inverse-leverage effect (ρ>0). [0105] Each burn-in runs in approximately 10 min on a 1 GHz Pentium-III WinXP machine. For X t timeseries that are 300 to 500 long, each 50,000 iteration sampling requires approximately 50 min elapsed wall-clock time. [0106] It is important to check convergence to ensure that the sample is drawn from a stationary distribution. Therefore, results are preferably based on samples of not less than 10,000 iterations and are more preferably based on 50,000-iteration samples, each of which passed Heidelberger, Welch, and Gelman-Rubin convergence tests for all parameters. [0107] Validation of the method was performed comparing two asymmetric SV models with Bayes factors. Specifically, the method of the present invention calculates the Bayes factors using the marginal likelihood approach of Chib (2002). The proposed ASV is as shown in Eq. (7) and Jacquier's ASV is as Eq. (8): { X t = σ t ⁢ u t , ln ⁢   ⁢ σ t + 1 2 = α + ϕlnσ t 2 + ρσ υ , σ t - 1 ⁢ X t + σ υ ⁢ 1 - ρ 2 ⁢ w t + 1 , ⁢ ⁢ and Eq ⁢ .7 { X t = σ t ⁡ ( 1 - ρ 2 ⁢ ∈ t ⁢ + ρ σ υ ⁢ ( ln ⁢   ⁢ σ t 2 - α - ϕlnσ t - 1 2 ) ) , ln ⁢   ⁢ σ t 2 = α + ϕlnσ t - 1 2 + σ υ , v t , ⁢ ⁢ where ⁢   ⁢  ⁢ w t + 1 =   ⁢ ( v t + 1 -   ⁢ pu t ) /   ⁢ 1 - ρ 2 ⁢   ⁢ and ⁢ ∈ t =   ⁢ ( u t -   ⁢ pv t ) ⁢   ⁢ 1 - ρ 2 ⁢   . Eq ⁢ .8 [0108] For back-testing various example stocks, a series of sentinel dates was selected for each, straddling relevant moments when decisions affecting the security were publicly released (e.g., IMCL, re: FDA's approval of erbitux on 12Feb. 2004; see Table I below and FIG. 6 ). Then historical end-of-day prices were downloaded and pre-processed for use with WinBUGS. The pattern of σ v was examined, to ascertain whether σ v (or other variables derived from it) could serve as a signal of the shift in share price that was consequent upon the decision or news. [0109] Generally, the evolution of σ v is relatively slow, with shifts in investor sentiment manifesting themselves over periods of 10 or more trading days, more than sufficient time for the trader to undertake buy or sell trades to achieve the desired position in the security. TABLE I DATE MONTH SIGMAV RHO −SIG/RHO LNDELSIG PRICE 12-Dec-03 1 0.6058 −0.2423 2.500 0.002 $40.45 12-Jan-04 2 0.5903 −0.2570 2.297 −0.026 $40.90 12-Feb-04 3 0.6327 −0.2242 2.822 0.069 $34.00 12-Mar-04 4 0.6596 −0.2272 2.903 0.042 $46.51 23-Apr-04 5 0.6364 −0.2530 2.515 −0.036 $70.30 [0110] WinBUGS code implementing the ASV model of the present invention in Eq. (7) is: model { mu ˜ dnorm(0,0.04) phistar ˜ dbeta(20,1.5) itau2 ˜ dgamma(2.5,0.025) rho ˜ dunif(−1,1) #beta <− exp(mu/2) phi <− 2*phistar − 1 pi <− 3.141592654 sigmav <− sqrt(1/itau2) theta0 ˜ dnorm(mu,itau2) thmean[1] <− mu + phi*(theta0 − mu) theta[1] ˜ dnorm(thmean[1],itau2)I(−100,100) for (i in 2:N) { thmean[i] <− mu + phi*(theta[i−1] − mu) theta[i] ˜ dnorm(thmean[i],itau2)I(−80,80) } for(i in 1:(N−1)) { Xmean[i] <− rho/sigmav*exp(0.5*theta[i])* (theta[i+1] − mu − phi*(theta[i] − mu)) Xisigma2[i] <− 1/(exp(theta[i])*(1 − rho*rho)) X[i] ˜ dnorm(Xmean[i],Xisigma2[i]) loglike[i] <− (−0.5*log(2*pi) + 0.5*log(Xisigma2[i]) − 0.5*Xisigma2[i]*X[i]*X[i]) } #Xmean[N] <− mu − phi*(theta[N] − mu) Xmean[N] <− 0 Xisigma2[N] <− 1/(exp(theta[N])) X[N] ˜ dnorm(Xmean[N],Xisigma2[N]) loglike[N] <− (−0.5*log(2*pi) + 0.5*log(Xisigma2[N]) 0.5*Xisigma2[N]*X[N]*X[N]) node1 <− −sum(loglike[]) } #data ... #inits ... [0111] The method takes the historical end-of-day price timeseries P(t) for the selected security, transforms this series to the logarithmic asset price s(t)=ln(P(t)), and calculates X t =s(t+1)−s(t), which is equivalent to pairwise daily returns: ln(P(t+1)/P(t)). The parameters sigmav, rho, phi, and mu are monitored. The natural logs of the ratios of adjacent values of sigmav are calculated: ln(sigmav(t+1)/sigmav(t)). This normalized LNDELSIG value appears to be a robust leading indicator of an impending rally in small- and mid-cap equities characterized by thin trading in advance of general awareness of information that bears on the firm's long-term prospects. Values of LNDELSIG >0.05 consistently signal an impending rise in share price of 2 × or more. Likewise, impending breakdowns (“gap-downs”) on negative news are also consistently signaled by LNDELSIG. [0112] Understanding the finite-sample performance of Bayes MCMC estimators is important in several respects. First, it checks the reliability of the proposed Bayes MCMC estimators for the ASV model, in particular for the new leverage estimator, ρ. Second, since more estimation tools have recently been developed to estimate the discrete-time ASV models than continuous-time ASV models, it is interesting to compare directly the performance of Bayes MCMC estimates with other estimates in the discrete-time context. Sampling experiments were designed to examine the sampling properties of the proposed MCMC estimates for the new discrete-time ASV model, as applied to certain small- and mid-cap equities in the healthcare, pharma/biopharma, and biotech sectors, whose prospects and operating environment are subject to considerable uncertainty and speculation. [0113] The Markov Chain Monte Carlo (MCMC) calculation functionality in the preferred embodiment is provided by BUGS™ or, more recently, WinBUGS™. However, any of a variety of Bayesian MCMC software applications are able to implement the Bayesian models discussed in earlier sections of the present invention. [0114] While a preferred embodiment of the present invention and variations thereon have been set forth in detail above, those skilled in the art who have reviewed the present disclosure will readily appreciate that other embodiments can be realized within the present invention. For example, disclosures of specific computing and networking technologies are illustrative rather than limiting. Therefore, the present invention should be construed as limited only by the appended claims.

A system suitable for an automated investment share price pattern search includes a computer, a historical information database accessible by the computer having historical information for a plurality of investments stored thereon, a connection to a supply of real-time or historical timeseries data, the data comprising real-time or historical data relating to a plurality of investments. Software executing on the computer generates an investment classification for the investment to be examined based upon the historical information and the real-time data relating to the investment or investments to be examined. The process gathers price and volume data of listed firms from arbitrarily many stock markets. The invention uses the statistics of asymmetric stochastic volatility (ASV) to classify and associate the recent fluctuations in share price with a recommended action: sell, buy, or hold.

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit, under 35 U.S.C. §119(e), of the filing date of U.S. provisional application Ser. No. 60/360,499 entitled “Methods for Extending Offset Correction Range in Pipelined ADC System,” filed Feb. 28, 2002 and incorporated herein by reference. FIELD OF THE INVENTION The present invention is directed generally to the field of analog-to-digital converters. In particular, the invention relates to methods and apparatuses for analog-to-digital converters having an increased input range. DESCRIPTION OF THE RELATED ART FIG. 1A illustrates a typical signal processing system 1 . Signal processing system 1 includes an analog signal processor (ASP) 3 , an analog-to-digital converter (ADC) 5 , and a digital signal processor (DSP) 7 . ASP 3 processes signals of an analog format, and ADC 5 converts the analog signals into a digital format. DSP 7 processes the signals of a digital format. Offsets often exist in signal processing system 1 , which may result in a difference between a desired output code of ADC 5 and the actual output code for a given reference input. These offsets may be generated in ASP 3 , ADC 5 , and/or may exist at the input of ASP 3 . The offset that may exist at the input of ASP 3 is represented in FIG. 1A as V OS, INPUT , the offset that may be generated in ASP 3 is represented in FIG. 1A as V OS, ASP , and the offset that may be generated in ADC 5 is represented in FIG. 1A as V OS, ADC . Offsets V OS, INPUT , V OS, ASP , and V OS, ADC , are collectively represented in equivalent form at the input of ADC 5 as equivalent voltage offset V OS, EQ in FIG. 2 . It is often desirable to cancel this offset to simplify the interface between ADC 5 and DSP 7 , and to maintain the dynamic range and DC accuracy of the processed signal. FIGS. 2A and 2B illustrate two conventional methods for correction of offset V OS, EQ shown in FIG. 2 . FIG. 2A illustrates analog offset correction, wherein a voltage representing the offset voltage at the output of DSP 7 is subtracted from the signal at the input of ADC 5 via offset calibration logic 9 . FIG. 2B illustrates digital offset correction, wherein a voltage representing the offset voltage at the output of DSP 7 is subtracted from the signal at the input of DSP 7 via offset calibration logic 8 . Digital offset correction provides certain advantages over analog offset correction. In particular, digital offset correction provides good accuracy, no additional noise, and a flexible response to residual offset error. However, digital offset correction does not eliminate the presence of V OS, EQ at the input of ADC 5 . The presence of equivalent offset voltage V OS, EQ at the input of ADC 5 reduces the dynamic range of ADC 5 . Further, if equivalent offset voltage V OS, EQ causes saturation of ADC 5 input, digital offset correction cannot be used to correct the offset. In view of the foregoing, an object of the present invention to provide methods and apparatuses for increasing the input range of an ADC. SUMMARY OF THE INVENTION One embodiment of the invention is directed to a method of extending the input range of an analog-to-digital converter (ADC) having a nominal input voltage range. The method comprises an act of mapping an over-range input voltage that falls outside of the nominal input voltage range to an over-range digital output code. Another embodiment of the invention is directed to an apparatus comprising an ADC having a nominal input voltage range, wherein the ADC is adapted to map an over-range input voltage that falls outside of the nominal input voltage range to an over-range digital output code. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A is a block diagram of a conventional signal processing system with an input offset, analog signal processor offset, and analog-to-digital converter (ADC) offset; FIG. 1B is a block diagram of the signal processing system of FIG. 1A with an equivalent offset; FIG. 2A is a block diagram of the signal processing system of FIG. 1A with analog offset correction; FIG. 2B is a block diagram of the signal processing system of FIG. 1A with digital offset correction; FIG. 3 is a block diagram of a pipelined ADC; FIG. 4 is a schematic representation of a sub-ADC of the pipelined ADC of FIG. 3 ; FIG. 5 shows digital output codes that may be output from the sub-ADC of FIGS. 3-4 and corresponding input voltages for the sub-DAC of FIG. 3 ; FIG. 6 shows the correspondence between the thermometer-coded and binary-coded outputs of the sub-ADC of FIG. 4 ; FIG. 7A is a schematic representation of a sub-DAC of the pipelined ADC of FIG. 3 ; FIG. 7B shows voltage signals used in the activation of switches in the sub-DAC of FIG. 7A ; FIG. 8A is a schematic representation of the sub-DAC of FIG. 7A activated in a sample phase; FIG. 8B is a schematic representation of the sub-DAC of FIG. 7A activated in a hold phase; FIG. 9A shows the residue plot output of the sub-DAC of FIG. 7A FIG. 9B shows the transfer function of the pipelined ADC of FIG. 3 ; FIG. 9C shows an ideal transfer function for the sub-ADC of FIG. 3 ; FIG. 9D shows an output of the sub-ADC of FIG. 3 ; FIGS. 10A-C show one implementation of the error correction logic of FIG. 3 ; FIGS. 11A-C show one example of mapping that may occur in the error correction logic of FIG. 3 ; FIG. 12 shows the usable input range of a pipelined ADC constructed in accordance with an embodiment of the invention; FIG. 13 is a block diagram of a pipelined ADC in accordance with one embodiment of the invention: FIG. 14 is a schematic representation of one implementation of the sub-ADC of FIG. 13 in accordance with an embodiment of the invention; FIG. 15 shows the correspondence between the thermometer-coded and binary-coded outputs of the sub-ADC of FIG. 14 ; FIGS. 16A-E show an implementation of the error correction logic of FIG. 3 in accordance with an embodiment of the invention; FIGS. 17A-C show an example of mapping that may occur in the error correction logic of FIG. 3 in accordance with an embodiment of the invention; FIG. 18A shows a residue plot of a pipelined ADC constructed in accordance with another embodiment of the invention; FIG. 18B shows the transfer function of a pipelined ADC having the residue plot of FIG. 18A ; FIG. 19 is a block diagram of a pipelined ADC that corresponds to the residue plot of FIG. 18A ; FIG. 20 is a schematic representation of a sub-ADC of the pipelined ADC of FIG. 19 ; FIG. 21 shows digital output codes that may be output from the sub-ADC of FIG. 20 and corresponding input voltages for the sub-DAC of FIG. 23A ; FIG. 22 shows the correspondence between the thermometer-coded and binary-coded outputs of the sub-ADC of FIG. 20 ; FIG. 23A is a schematic representation of a sub-DAC of the pipelined ADC of FIG. 19 ; FIG. 23B shows voltage signals used in the activation of switches in the sub-DAC of FIG. 23A ; FIG. 24A is a schematic representation of the sub-DAC of FIG. 23A activated in a sample phase; FIG. 24B is a schematic representation of the sub-DAC of FIG. 23A activated in a hold phase; and FIGS. 25A-C show an example of mapping that may occur in the error correction logic of FIG. 19 . DETAILED DESCRIPTION OF THE INVENTION One aspect of the invention is directed to increasing the input range of an analog-to-digital converter (ADC). According to one embodiment of the invention, input range is increased by mapping one or more digital output codes to one or more portions of the analog input range that are beyond the nominal input voltage range of the ADC. The digital output codes may be unique, and therefore not assigned to voltages in the nominal input voltage range. Increasing the input range of an ADC has many potential benefits. These benefits may have particular significance when an offset voltage is present at the input of the analog-to-digital converter. An offset voltage at the input of an ADC reduces the dynamic range of the converter. If the input range of an ADC having an input offset voltage is increased, the dynamic range of the ADC may be restored by increasing the input range by an amount greater than or equal to the input offset voltage. Further, if the ADC having the input offset voltage is saturated by an input signal, digital offset correction, which was discussed in connection with FIG. 3B , will not be effective to correct the offset voltage. If the input range of the ADC is increased by an amount greater than or equal to the voltage exceeding the nominal input voltage range of the ADC, saturation may be avoided and digital offset correction may be performed. Although enabling digital offset correction is one benefit of increasing the input range of an ADC, it should be appreciated that many other benefits exist, and that the invention is not limited in this respect. The operation and construction of a conventional ADC will now be described. FIG. 3 illustrates one implementation of a conventional ADC, such as ADC 5 of FIGS. 1-3 . Many types of ADCs exist, such as flash ADCs, algorithmic ADCs, and pipelined ADCs. FIG. 3 illustrates a block diagram of one exemplary ADC, which is a pipelined ADC 13 that generates m output bits and comprises n stages. Each stage of pipelined ADC 13 operates successively to resolve k bits of the m-bit output. Pipelined ADC 13 of FIG. 3 comprises a first stage 15 , a second stage 17 , a final nth stage 21 , and one or more intermediate stages, such as ith stage 19 . First stage 15 accepts a sample of analog signal Ain as stage input 23 . Then, as illustrated for ith stage 19 , which generically illustrates the processing that occurs in each of stages 1 through n, stage input 23 is quantized to k bits by a sub-ADC 25 . These k bits are transmitted to error correction logic 35 , which implements synchronization and correction functions. The bits are also transmitted to a sub-digital-to-analog converter (DAC) 27 , which converts the digital voltage into an analog voltage. The analog voltage is subtracted from stage input 23 by an adder 29 . The result of this operation is then multiplied by a factor of 2 (ki−1) by a multiplier 31 , where i is the stage number. The output of multiplier 31 represents the residue 33 of the stage, which is passed to the input of the next stage, if present, for further processing. After each stage has transmitted k bits to error correction logic 35 , the error correction logic assembles and outputs m bits as digital output 37 . FIG. 4 illustrates one implementation of sub-ADC 25 of FIG. 3 . The sub-ADC 39 of FIG. 4 comprises four comparators 41 A-D, each of which outputs one digital bit of a digital output code. Each of comparators 41 A-D comprises first and second input terminals 43 A-B. The first input terminal 43 A of each comparator 41 A-D is coupled to stage input 23 . The second input terminal 43 B of each comparator 41 A-D is coupled to a node 45 A-D on a string of resistors 51 coupled between two reference voltages −Vr and +Vr, where 2Vr is the nominal input range of sub-DAC 25 . As shown, resistors 47 A-C have a resistance that is twice that of resistors 49 A-B, although other implementations are possible. Because the string of resistors 51 acts as a voltage divider, each node 46 A-D on the string is at a different voltage level. Hence, each comparator 41 A-D compares stage input 23 with a different voltage level. A logic one is output by any comparator coupled to a node at a lower voltage than stage input 23 , and a logic zero is output by comparators coupled to a node at a higher voltage than stage input 23 . The voltage level to which stage input 23 is compared is successively higher for comparators 41 A, 41 B, 41 C, and 41 D, respectively. Accordingly, comparator 41 A outputs the least significant bit of the output code of sub-ADC 39 , and comparator 41 D outputs the most significant bit. Comparators 41 A- 41 D may output five different output codes D 0 -D 3 , as shown in FIG. 5 . Each output code will contain a logic one for each comparator that is connected to a node having a lower voltage than stage input 23 . Hence, if none of the comparators is connected to a node on resistor string 51 having a lower voltage than stage input 23 , each of comparators 41 A-D will output a logic zero, and the output code will be 0000. Conversely, if all of the comparators are connected to a node having a lower voltage than stage input 23 , each of comparators 41 A-D will output a logic one, and the output code will be 1111. The output of comparators 41 A- 41 D is transmitted to sub-DAC 27 of FIG. 3 as bits D 0 -D 3 . The output is also transmitted to a thermometer-to-binary converter 48 , which converts the thermometer code output of comparators 41 A- 41 D to binary code bits B 0 -B 1 . The conversion is performed according to the thermometer-binary correspondences set forth in table a FIG. 6 . The binary code output of sub-ADC 51 is transmitted to error correction logic 35 (FIG. 3 ). FIG. 7A , illustrates one implementation of the sub-DAC 27 , adder 29 , and multiplier 31 of FIG. 3 . In particular, FIG. 7A illustrates a block diagram of a conventional 2-bit multiplying digital-to-analog converter (MDAC) 53 . MDAC 53 comprises inputs INPUT+ and INPUT− for receiving a stage input. MDAC 53 further comprises four pairs of input capacitors, each input capacitor 55 A-H connected via a switch Q 1 to one of the inputs INPUT+ or INPUT−. Each of input capacitors 55 A-H is also connected to a reference voltage, either top reference voltage REFT or bottom reference voltage REFB, at a node V 0 P-V 3 N via a switch Q 2 . Half of the input capacitors are connected to a first input terminal 57 A of an operational amplifier 59 , and half of the input capacitors are connected to a second input terminal 57 B of operational amplifier 59 . The first and second input terminals 57 A-B are also connected to common mode level voltage CML, via switches Q 1 , and to first and second output terminals 61 A-B of operational amplifier 59 via switches Q 2 and feedback capacitors 63 A-B. Feedback capacitors 63 A-B may have a capacitance that is twice that of input capacitors 55 A-H. The first and second input terminals 57 A-B of operational amplifier 59 are linked via a switch Q 1 . MDAC 53 is activated in two phases: a sample phase and a hold phase. The activation of the two phases may be controlled by signals that control switches Q 1 and Q 2 . An example of such signals is shown in FIG. 7 B. The sample phase, during which switches Q 1 are closed, is illustrated in FIG. 7 A. When switches Q 1 are closed, four input capacitors 55 A-D are connected in parallel between INPUT+ and common mode level voltage CML, and the remaining four input capacitors 55 E-H are connected in parallel between INPUT− and common mode level voltage CML. Each of input capacitors 55 A-H may have an equivalent capacitance. Because stage input 23 is applied between INPUT+ and INPUT−, input capacitors 55 A-H are charged according to the magnitude of stage input 23 . After a time sufficient for input capacitors 55 A-H to charge, switches Q 1 are opened and switches Q 2 are closed. In one example, switches Q 2 may be closed after switches Q 1 are opened. The hold phase, during which switches Q 2 are closed, is illustrated in FIG. 8 B. When switches Q 2 are closed, each input capacitor 55 A-H is connected to a reference voltage, either top reference voltage REFT or bottom reference voltage REFB, selected according to the digital output of sub-ADC 39 . FIG. 5 illustrates the voltage applied to each input capacitor 55 A-H in FIG. 7A for each of five possible output codes of sub-ADC 39 . As may appreciated from the table, each pair of input capacitors 55 A-H includes one capacitor coupled to top reference voltage REFT and one capacitor coupled to bottom reference voltage REFB. The difference between top reference voltage REFT and bottom reference voltage REFB is Vr. Hence, either +Vr or −Vr is applied to each pair of input capacitors, according to the output code of sub-ADC 39 . For example, if the output code of sub-ADC 39 is 0000, −Vr is applied to each pair, and if the output code of sub-ADC 39 is 1111, +Vr is applied to each pair. A charge proportional to the difference between stage input 23 and its quantized approximation is forced onto feedback capacitors 63 A-B, which produces residue voltage 33 across outputs 61 A-B. FIG. 9A illustrates an example of a residue plot for a conventional stage generating 2 bits (i.e., k= 2 ). The residue plot results from the subtraction of Ain, shown in FIG. 9C with relation to the Aout, and Ain quantized to two bits, shown in FIG. 9 D. The ideal transfer function of sub-ADC 27 of FIG. 3 is shown as a voltage ramp in FIG. 9C. A 2-bit quantization of the voltage ramp shown in FIG. 9C results in the step function shown in FIG. 9 D. As shown in FIG. 9B , the nominal input range of sub-ADC 25 ( FIG. 3 ) spans from −1V to 1V. The nominal input range represents the range of Ain for which unique output codes ordinarily exist in a conventional ADC. Hence, the maximum analog voltage in the nominal input range is assigned to the maximum digital output code generated in a conventional ADC, and the minimum analog voltage in the nominal input range is assigned to the minimum digital output code. Above and below the nominal input range, the output is clipped to avoid duplicate output codes. FIGS. 10A-C illustrate one implementation of the error correction logic 35 of FIG. 3 . Error correction logic 109 accepts the binary output codes of the sub-ADC 25 of each stage of FIG. 3 as input 111 , and generates an m-bit output code as output 113 . Offset corrector 123 corrects for quantization errors of the input 111 , and maps the received codes to the transfer function shown in FIG. 10 B. The transfer function of FIG. 10B maps those codes falling within the nominal input range of the ADC 13 , which is between −1V and +1V in the example of FIGS. 10A-C . Error correction logic 109 detects codes representing an analog input voltage outside of the nominal input range. In particular, detector 115 detects “below-range” codes, or those corresponding to an analog input below −1V. Detector 117 detects “above-range” codes, or those corresponding to an analog input above +1V. Error correction logic 109 sets all “below-range” codes to a minimum limit code 121 , which may be “00” in one example. Conversely, error correction logic 109 sets all “above-range” codes to a minimum limit code 119 , which may be “ 11 ” in one example. Logic circuit 125 processes the outputs of detector 115 , detector 117 , and offset correction 123 and outputs m bits as output 113 . FIGS. 11A-C show one example of mapping that may occur in the error correction logic 109 of FIG. 10 A. FIG. 11A illustrates one example of an assignment of binary codes 127 , output from sub-ADC 39 , to the residue segments of the residue plot of FIG. 9 A. Mapping algorithm 129 , shown in FIG. 11B , maps binary codes 127 to the transfer function of FIG. 11 C. Mapping algorithm 129 , which may be implemented as circuitry in the offset corrector 123 of FIG. 10A , reassigns binary codes 127 to corrected binary codes 131 . The mapping algorithm computes the reassignment by identifying regions of the residue plot of FIG. 11A where Aout is less than zero, and subtracting one from the corresponding binary code 127 of each identified region. The mapping that occurs via mapping algorithm 129 results in a transfer function for pipe lined ADC 13 as shown in FIG. 11 C. In the conventional ADC discussed above in connection with FIGS. 1-11 , unique digital output codes are generated for the analog voltages within the nominal input range of the ADC. Hence, the minimum value digital code of 00 was assigned to the minimum analog voltage within the nominal input range (i.e., −1V) and the maximum value digital code of 11 was assigned to the maximum analog voltage within the nominal input range (i.e., +1V). According to this scheme, the ADC output m bits, and hence 2 m output codes. In accordance with one embodiment of the invention, the input range of a conventional ADC is extended to allow over-range input voltages outside of the nominal input range of the ADC. The over-range voltages may be converted to unique digital output codes. Hence, the number of output codes that may be generated by the ADC is increased with respect to a conventional ADC. The dynamic range of the ADC is also increased. A first illustrative embodiment of an ADC having an extended input range will be discussed below in connection with FIGS. 12-17 . FIG. 12 illustrates the residue plot of FIG. 3 for an extended input range. The nominal input range 135 of the residue plot of FIG. 12 extends from −1V to +1V, as was the case in FIG. 3 . However, in FIG. 3 , analog output voltages falling outside of the nominal input range were clipped. In a conventional ADC, the voltages above and below the nominal input range are clipped, as these regions produced no unique output codes and are unnecessary for conversion of the analog input. These regions are also unusable for conversion of the analog output as no additional useful information exists in these regions. However, it may be appreciated from FIG. 12 that the analog output Aout of a sub-DAC continues to change beyond the nominal input range in the “above-range” region above 1V and the “below-range” region below −1V. In accordance with the present embodiment, an ADC may be adapted to convert above-range voltages and/or below-range voltages to unique output codes. One exemplary implementation of such an ADC will now be discussed in connection with pipelined ADC 12 of FIG. 13 . However, it should be appreciated that the invention is not limited in this respect, and that other types of ADCs, such as a flash ADC or algorithmic ADC, may be adapted to convert above-range voltages and/or below-range voltages to unique output codes by applying the principles described herein. FIG. 13 illustrates a pipelined ADC 12 that is similar in many respects to the pipelined ADC 13 of FIG. 3 , but has been modified in accordance with one implementation of the presently described embodiment. In particular, sub-ADC 26 has been modified as discussed in connection with FIG. 14 , and error correction logic 34 has been modified as discussed in connection with FIGS. 16-17 and generates an m+1 bit output 36 . In other respects, pipelined ADC 65 operates according to the same principles as the pipelined ADC 13 described in connection with FIG. 3 . In the residue plot of FIG. 13 nominal input range 135 extends from −Vr to +Vr, where Vr equals 1V. The usable input range 133 extends from −3/2Vr to +3/2Vr. Hence, as may be appreciated from the residue plot of FIG. 12 , the usage input range of ADC 13 ( FIG. 3 ) may be increased by Vr/2 (k-2) , where k is the number of bits resolved in the stage. Hence, the dynamic range of the ADC may be increased by Vr, beyond the nominal input range of 2Vr, when k equals 2. FIG. 14 illustrates an exemplary implementation of the sub-ADC 26 of FIG. 13 in accordance with the presently described embodiment. Sub-ADC 133 of FIG. 14 is implemented as shown and described for the sub-ADC 51 of FIG. 4 , with the exception of thermometer-to-binary converter 135 . As shown in FIG. 15 , thermometer-to-binary converter 135 converts the thermometer code output of comparators 41 A- 41 D to a three-bit binary code as bits B 0 -B 2 . The conversion is performed according to the thermometer-binary correspondences set forth in FIG. 15 . Since the output of comparators 41 A- 41 D is converted to a three-bit binary code, rather than a two-bit binary code as in the sub-ADC 51 of FIG. 4 , a unique code may be assigned for each of the five possible thermometer output codes of comparators 41 A- 41 D. The three-bit binary code output of sub-ADC 133 is transmitted to error correction logic 35 (FIG. 3 ). FIGS. 16A-E illustrate an exemplary implementation of the error correction logic 34 of FIG. 13 in accordance with the presently described embodiment. Error correction logic 139 accepts the binary output codes of the sub-ADC 26 of each stage of FIG. 13 , which may be implemented as shown for sub-ADC 133 of FIG. 14 , as input 137 . Error correction logic 139 generates an m+1 bit output code as output 141 . Error correction logic 139 detects codes representing an analog input voltage outside of nominal input range 135 (FIG. 12 ). In particular, detector 143 detects “below-range” codes, or those corresponding to an analog input below −1V. Detector 145 detects “above-range” codes, or those corresponding to an analog input above +1V. Code mapper 147 processes the below-range codes by mapping the codes to the partial transfer function of FIG. 16 B. The transfer function of FIG. 16B maps those codes falling below the nominal input range of ADC 133 , which is below −1V in the present example. Similarly, code mapper 149 processes the above-range codes by mapping the codes to the partial transfer function of FIG. 16 C. The transfer function of FIG. 16C maps those codes falling above the nominal input range of ADC 133 , which is above +1V in the present example. Offset corrector 151 corrects for quantization errors of the input 137 , and processed the codes within the nominal input range by mapping the codes to the transfer function of FIG. 16 D. The transfer function of FIG. 16D maps those codes falling within the nominal input range of the ADC 133 , which is between −1V and +1V in the present example. Logic circuit 153 processes the outputs of detectors 143 , 145 , code mapper 147 , code mapper 149 , and offset corrector 151 , and outputs m+1 bits as output 141 . Thus, it should be appreciated that for an m−bit ADC, the techniques described in connection with FIGS. 12-16 provide an additional output bit relative to the conventional ADC described previously. FIGS. 17A-C show one example of mapping that may occur in the error correction logic 139 of FIG. 16 A. FIG. 17A , illustrates one example of an assignment of binary codes 155 , output from sub-ADC 133 , to the residue segments of the residue plot of FIG. 12 . Mapping algorithm 156 , shown in FIG. 17B , maps binary codes 155 to the transfer function of FIG. 17 C. Mapping algorithm 156 , which may be implemented as circuitry in the code mappers 147 , 149 and offset corrector 151 of FIG. 16A , reassigns binary codes 155 to corrected binary codes 157 . The mapping algorithm computes the reassignment by identifying regions of the residue plot of FIG. 17A where Aout is less than zero, and subtracting one from the corresponding binary code 155 of each identified region. The mapping that occurs via mapping algorithm 156 results in a transfer function for pipelined ADC 13 as shown in FIG. 17 C. It should be appreciated that the mappings described above are given by way of example only, and that numerous alternative mappings are possible, and may be used in accordance with the invention. According to another embodiment of the invention, an ADC may be modified to further increase the input range of the ADC by assigning one or more additional unique codes in the over-range regions. In one illustrative implementation, which will be described in connection with FIGS. 18-25 , a pipelined ADC is modified so that, in one or more stages, a sub-ADC thereof generates one or more residue segments outside of the nominal input voltage range. Each additional residue segment may produce an additional stage output code. The stage output codes may be processed in error correction logic of the ADC to generate additional ADC output codes outside of the nominal input voltage range. FIG. 18A illustrates an example of a residue plot for a stage of an ADC having residue segments outside of the nominal input voltage range. The residue plot of FIG. 18A corresponds to an ADC having a nominal input voltage range of −1V to +1V. In FIG. 18A , complete residue segments exist between each of −2V and −5/4V and +5/4V and +2V, beyond the nominal input voltage range of the ADC. A unique output code may be assigned to each segment, extending the usable input range of the ADC to between −2V and +2V. As shown in FIG. 18B , the usable input range of the modified ADC is double that of the nominal input range. As may be appreciated from the reside plot of FIG. 18A , input range may be increased by Vr/2 (k-1) for each residue segment added, where k is the number of bits resolved in the stage, and Vr is one half of the nominal input range. Hence, the dynamic range of the ADC may be increased by 2Vr beyond the nominal input range of 2Vr. As shown in FIG. 18A , the usable input range extends between 2Vr and −2Vr, or 2V and −2V where Vr=1V. FIG. 19 illustrates a pipelined ADC 65 that has been modified to be usable in an ADC constructed in accordance with the described embodiment. Pipelined ADC 65 operates according to the same principles as the pipelined ADC 13 described in connection with FIG. 3 . However, sub-ADC 77 , sub-DAC 79 , and error correction logic 82 are modified so that pipelined ADC 65 generates residue segments outside of the nominal input range of the ADC. Pipelined ADC 65 of FIG. 3 comprises a first stage 67 , a second stage 69 , a final nth stage 73 , and one or more intermediate stages, such as ith stage 71 . First stage 67 accepts a sample of analog signal Ain as stage input 75 . Then, as illustrated for ith stage 71 , which generically illustrates the processing that occurs in each of stages 1 through n, stage input 75 is quantized to k bits by sub-ADC 77 . These k bits are transmitted to error correction logic 82 , which implements synchronization and correction functions. The bits are also transmitted to sub-digital-to-analog converter (DAC) 79 , which converts the digital voltage into an analog voltage. The analog voltage is subtracted from stage input 75 by adder 29 . The result of this operation is then multiplied by a factor of 2 (ki-1) by multiplier 31 , where i is the stage number. The output of the multiplier 31 represents residue 81 of the stage, which is passed to the input of the next stage, if present, for further processing. After each stage has transmitted k bits to error correction logic 82 , the error correction logic assembles and outputs m+1 bits as digital output 83 . FIG. 20 illustrates one implementation of the sub-ADC 77 of FIG. 19 . Sub-ADC 77 is constructed in a manner similar to sub-ADC 25 of FIG. 3 , but includes two additional comparators and two additional resistors. As shown in FIG. 21 , the six comparators 85 A-F may output six different output codes. Each of comparators 85 A-F comprises first and second input terminals 87 A-B. The first input terminal 87 A of each comparator 85 A-F is coupled to stage input voltage 75 . The second input terminal 87 B of each comparator 85 A-F is coupled to a node 89 A-F on a string of resistors 91 coupled between two reference voltages −3/2Vr and 3/2Vr. As shown, resistors 93 A-E have a resistance that is twice that of resistors 95 A-B, although other implementations are possible. Because the string of resistors 91 acts as a voltage divider, each node 89 A-F on the string is at a different voltage level. Hence, each comparator 85 A-F compares stage input voltage 75 with a different voltage level. A logic one is output by any comparator coupled to a node at a lower voltage than stage input voltage 75 , and a logic zero is output by comparators coupled to a node at a higher voltage than stage input voltage 75 . The voltage level to which stage input voltage 75 is compared is successively higher for comparators 85 A, 85 B, 85 C, 85 D, 85 E, and 85 F, respectively. Accordingly, comparator 85 A outputs the least significant bit of the output code of sub-ADC 77 , and comparator 85 F outputs the most significant bit. The output of comparators 85 A-F is transmitted to sub-DAC 77 of FIG. 19 as bits D 0 -D 5 . The output is also transmitted to a thermometer-to-binary converter 90 , which converts the thermometer code output of comparators 85 A-F to binary code as bits B 0 -B 2 . The conversion is performed according to the thermometer-binary correspondences set forth in FIG. 22 . The binary code output of sub-ADC 91 is transmitted to error correction logic 82 (FIG. 19 ). FIG. 23A illustrates one implementation of the sub-DAC 79 , adder 29 , and multiplier 31 of FIG. 19 . In particular, FIG. 23A illustrates a block diagram of a multiplying digital-to-analog converter (MDAC) 99 . MDAC 99 comprises inputs INPUT+ and INPUT− for receiving a stage input. MDAC 99 further comprises five pairs of input capacitors 97 A-J. Four pairs, including input capacitors 97 B-I, are connected via a switch Q 1 to one of inputs INPUT+ or INPUT−. The fifth pair, including input capacitors 97 A, J, is connected via a switch Q 1 to common mode level voltage CML. The input capacitors 97 A, J may have a capacitance that is twice that of input capacitors 97 B-I. Each of input capacitors 97 A-J is also connected to a reference voltage at a node V 0 P-V 4 N via a switch Q 2 . The reference voltage may be common mode level voltage CML, top reference voltage REFT, or bottom reference voltage bottom reference voltage REEB. Half of the input capacitors are connected to a first input terminal 101 A of an operational amplifier 107 , and half of the input capacitors are connected to a second input terminal 101 B of operational amplifier 107 . The first and second inputs are also connected to common mode level voltage CML, via switches Q 1 , and to first and second output terminals 103 A-B of operational amplifier 107 via switches Q 2 and output capacitors 105 A-B. The first and second input terminals 101 A-B of operational amplifier 107 are linked via a switch Q 1 . MDAC 99 is activated in two phases: a sample phase and a hold phase. The sample phase, during which switches Q 1 are closed, is illustrated in FIG. 24 A. When switches Q 1 are closed, four input capacitors 97 B-E are connected in parallel between INPUT+ and common mode level voltage CML, and four input capacitors 97 F-I are connected in parallel between INPUT− and common mode level voltage CML. Input capacitors 97 A, J are each connected between common mode level voltage CML, which is coupled to both sides of each capacitor. Each of input capacitors 97 A-J may have an equivalent capacitance. Because stage input 75 is applied between INPUT+ and INPUT−, input capacitors 97 B-I are charged according to the magnitude of stage input 75 . Input capacitors A, J, which are not connected between a voltage differential, are not charged. After a time sufficient for input capacitors 97 B-I to charge, switches Q 1 are opened and switches Q 2 are closed. In one example, switches Q 2 may be closed after switches Q 1 are opened. The hold phase, during which switches Q 2 are closed, is illustrated in FIG. 24 B. When switches Q 2 are closed, each input capacitor 97 A-J is connected to a reference voltage. The reference voltage may be common mode level voltage CML, top reference voltage REFT, or bottom reference voltage REFB, and is selected according to the digital output of the sub-ADC. FIG. 21 illustrates the voltage applied to each input capacitor 97 A-J in FIG. 24B for each of seven possible output codes of the sub-ADC 83 of FIG. 20 . As may be appreciated from the table, each pair of input capacitors 97 A-J includes one capacitor coupled to top reference voltage REFT and one capacitor coupled to bottom reference voltage REFB. The difference between top reference voltage REFT and bottom reference voltage REFB is Vr. Hence, either +Vr or −Vr is applied to each pair of input capacitors 97 A-J, according to the output code of sub-ADC 83 . For example, if the output code of sub-ADC 83 is 000000, −Vr is applied to each pair, and if the output code of the sub-ADC is 111111, +Vr is applied to each pair. The coupling of top reference voltage REFT or bottom reference voltage REFB to input capacitors 97 B-I alone produces the residue voltage of a conventional MDAC shown in FIG. 9A across outputs 103 A-B. For a digital input of 000000, which corresponds to a stage input voltage of less than −Vr−Vr/2 k , input capacitor 97 A is switched to bottom reference voltage REFB and capacitor 97 J is switched to REFT, which adds +Vr to the residue obtained using input capacitors 97 B-I. For a digital input of 111111, which corresponds to a stage input voltage of greater than Vr+Vr/2 k , input capacitor 97 A is switched to top reference voltage REFT and capacitor 97 J is switched to bottom reference voltage REFB, which adds −Vr to the residue obtained using input capacitors 97 B-I. For a digital input of 100000, 110000, 111000, 111100, or 111110, which correspond to a stage input voltage between −Vr−Vr/2 k and Vr+Vr/2 k , both input capacitor 97 A and input capacitor 97 J are connected to CML, resulting in the same residue as for a conventional MDAC. FIGS. 25A-C show one example of mapping that may occur in the error correction logic 82 of FIG. 19 . FIG. 25A illustrates one example of an assignment of binary codes 159 , output from sub-ADC 77 , to the residue segments of the residue plot of FIG. 18 A. Mapping algorithm 162 reassigns binary codes 159 to corrected binary codes 161 . The mapping algorithm computes the reassignment by identifying regions of the residue plot of FIG. 25A where Aout is less than zero, and subtracting one from the corresponding binary code 159 of each identified region. The mapping that occurs via mapping algorithm 162 results in a transfer function for pipelined ADC 65 as shown in FIG. 25 C. It should be appreciated that the mappings described above are given by way of example only, and that numerous alternative mappings are possible, and may be used in accordance with the invention. It should be appreciated that sub-ADC 83 and sub-DAC 99 , illustrated in FIGS. 20 and 23A , respectively may be modified so that additional residue segments are generated in the residue plot of FIG. 18 A. In particular, sub-ADC 83 may be modified by adding an additional comparator 85 and resistor 93 for each additional residue segment, and sub-DAC 99 may be modified by adding an additional pair of capacitors 97 for each additional residue segment. Error correction logic 82 can then be modified to produce a unique output code for each additional residue segment in a similar manner to that discussed above in connection with FIG. 25A-C . It should further be appreciated that the method of extending the input range of an ADC described above in connection with pipelined ADC 65 ( FIG. 19 ) may be applied with other types of ADCs. In particular, the input range of an algorithmic ADC and/or a flash ADC may also be extended by assigning unique digital output codes that correspond to analog input voltages outside of the nominal input voltage range. Having thus described several illustrative embodiments of the invention, various alterations, modifications, and improvements will readily occur to those skilled in the art. Such alterations, modifications, and improvements are intended to be within the spirit and scope of the invention. Accordingly, the foregoing description is by way of example only and is not intended as limiting. The invention is limited only as defined in the following claims and the equivalents thereto.

One embodiment of the invention is directed to a method of extending the input range of an analog-to-digital converter (ADC) having a nominal input voltage range. The method comprises an act of mapping an over-range input voltage that falls outside of the nominal input voltage range to an over-range digital output code. Another embodiment of the invention is directed to an apparatus comprising an ADC having a nominal input voltage range, wherein the ADC is adapted to map an over-range input voltage that falls outside of the nominal input voltage range to an over-range digital output code.

BACKGROUND OF THE INVENTION This invention relates to the management of oil or gas reservoirs, and more particularly, to the analysis of the production of petroleum reservoirs. A petroleum reservoir is a zone in the earth that contains, or is thought to contain, one or more sources of commercially viable quantities of recoverable oil or gas. When such a reservoir is found, typically one or more wells are drilled into the earth to tap into the source(s) of oil or gas for producing them to the surface. The art and science of managing petroleum reservoirs has progressed over the years. Various techniques have been used for trying to determine if sufficient oil or gas is in the given reservoir to warrant drilling, and if so, how best to develop the reservoir to produce the oil or gas that is actually found. Every reservoir is unique because of the myriad of geological and fluid dynamic characteristics. Thus, the production of petroleum from reservoir to reservoir can vary drastically. These variations make it difficult to simply predict the amount of fluids and gases a reservoir will produce and the amount of resources it will require to produce from a particular reservoir. However, parties which are interested in producing from a reservoir need to project the production of the reservoir with some accuracy in order to determine the feasibility of producing from the reservoir. Therefore, in order to accurately forecast production rates from all of the wells in a reservoir, it is necessary to build a detailed computer model of the reservoir. Prior art computer analysis of production for an oil reservoir is usually divided into two phases, history matching and prediction. When an oil field is first discovered, a reservoir model is constructed utilizing geological data. Geological data can include such characteristics as the porosity and permeability of the reservoir rocks, the thickness of the geological zones, the location and characteristics of geological faults, and relative permeability and capillary pressure functions. This type of modeling is a forward modeling task and can be accomplished using statistical or soft computing methods. Once the petroleum field enters into the production stage, many changes take place in the reservoir. For example, the extraction of oil/gas/water from the field causes the fluid pressure of the field to change. In order to obtain the most current state of a reservoir, these changes need to be reflected in the model. History matching is the process of updating reservoir descriptor parameters in a given computer model to reflect such changes, based on production data collected from the field. Production data essentially give the fluid dynamics of the field, examples include water, oil and pressure information, well locations and performances. Thus, reservoir models use empirically acquired data to describe a field. Input parameters are combined with and manipulated by mathematical models whose output describes specified characteristics of the field at a future time and in terms of measurable quantities such as the production or injection rates of individual wells and groups of wells, the bottom hole or tubing head pressure at each well, and the distribution of pressure and fluid phases within the reservoir. In the history matching phase, geological data and production data of the reservoir and its wells are used to build a mathematical model which can predict production rates form wells in the reservoir. The process of history matching is an inverse problem. In this problem, a reservoir model is a “black box” with unknown parameter values. Given the water/oil rates and other production information collected from the field, the task is to identify these unknown parameter values such that the reservoir gives flow outputs matching the production data. Since inverse problems have no unique solutions, i.e., more than one combination of reservoir parameter values give the same flow outputs, a large number of well-matched or “good” reservoir models needs to be obtained in order to achieve a high degree of confidence in the history-matching results. Initially, a base geological model is provided. Next, parameters which are believed to have an impact on the reservoir fluid flow are selected. Based on their knowledge about the field, geologists and petroleum engineers then determine the possible value ranges of these parameters and use these values to conduct computer simulation runs. A computer reservoir simulator is a program which consists of mathematical equations that describe fluid dynamics of a reservoir under different conditions. The simulator takes a set of reservoir parameter values as inputs and returns a set of fluid flow information as outputs. The outputs are usually a time-series over a specified period of time. That time-series is then compared with the historical production data to evaluate their match. Experts modify the input parameters of the computer model involved in that particular simulation of the reservoir on the basis of the differences between computed and actual production performance and rerun the simulation of the computer model. This process continues until the computer or mathematical model behaves like the real oil reservoir. The prior art manual process of history matching is subjective and labor-intensive, because the input reservoir parameters are adjusted one at a time to refine the computer simulations. The accuracy of the prior art history matching process largely depends on the experiences of the geoscientists involved in modifying the geological and production data. Consequently, the reliability of the forecasting is often very short-lives, and the business decisions made based on those models have a large degree of uncertainty. As described-above, the prior art history matching process is very time consuming. On average, each run takes 2 to 10 hours to complete. Moreover, there can be more than one computer model with different input parameters which can produce flow outputs that are acceptable matches to the historical production data of the reservoir. This is particularly evident when the reservoir has a long production history and the quality of production data is poor. Determining which models can produce acceptable matches of the production data from a large pool of potentially acceptable computer models is cost prohibitive and time consuming. Because of those restrictions, only a small number of simulations can be run, and consequently only a small number of acceptable models are identified. As a result, the prior art history matching process is associated with a large degree of uncertainty as to the actual real world reservoir configuration. That large degree of uncertainty in the history matching phase also translates into a large degree of variability in the future production forecasts. There is a need to identify large numbers of acceptable computer models in the history matching phase that are consistent with the geological data and the historical production data for a given reservoir. The facilitation of multiple realizations in history matching enables one to reduce the uncertainty in the reservoir models. The second phase of the computer analysis of production for the oil reservoir is prediction or forecasting. Once an acceptable computer model has been identified, alternative operating plans of the reservoir are simulated and the results are compared to optimize the oil recovery and minimize the production costs. Because of the uncertainty in the reservoir model that has been generated from the prior art history matching process, any future production profile forecasted by that model also has a high degree of uncertainty associated with it. In addition, as described-above, there are a number of computer models that have to be utilized in the prediction phase in order to reduce the uncertainty in the production forecasts. For each good model that was identified in the history matching phase, computer simulations are run to give a future production profile. In this manner, a range of production forecasts are determined and used to optimize the future production of the reservoir. As with the simulations in the history matching phase, the computer simulation phase is time consuming and requires a great deal of expertise which limits the number of acceptable computer models that can be used in the prior art prediction phase. There is a need to efficiently analyze large numbers of acceptable computer models which have been identified in the history matching phase of the analysis of production for the oil reservoir. Even when experts are used in the analysis, there is much educated trial and error effort spent in choosing acceptable reservoir models in the history matching phase, running the simulations of the models, determining the optimal inputs for the models to predict future production forecasts, and analyzing the results from the models to determine the correct forecasts or a range of forecasts. This is time consuming and expensive, and it requires a highly skilled human expert to provide useful results. If the potential pool of reservoir models in the history matching phase of the analysis is under-sampled, the uncertainty in the computer analysis of production for the reservoir will increase. There is, therefore, a need to sample and identify as many acceptable reservoir models in the history matching phase as possible to reduce the degree of uncertainty associated with the results of the computer analysis. There is also a need to be able to efficiently analyze those identified acceptable models and provide production forecasts for the reservoir. The ability to more quickly and less expensively analyze a reservoir by whatever means is becoming increasingly important. Companies that develop oil or gas reservoirs are basing business decisions on entire reservoir analysis rather than just on individual wells in the field. Even after a field development plan is put into action, the computer analysis of production of the reservoir is periodically rerun and further tuned to improve the ability to match newly gathered production data. Because these decisions need to be made quickly as opportunities present themselves, there is the need for an improved method of analyzing petroleum reservoirs and, particularly, for accurately forecasting the oil and/or gas production of the reservoirs into the future. SUMMARY OF THE INVENTION The present invention overcomes the above-described and other shortcomings of the prior art by providing a novel and an improved method of utilizing computer models for predicting future production forecasts of petroleum reservoirs. In one embodiment of the present invention, for the history matching phase, an initial sampling of reservoir models which is related to a much larger set of possible reservoir models representing a petroleum reservoir is produced. A historical production profile is generated for each of this initial sample of reservoir models. Each of the initial samples of reservoir models is qualified as either acceptable or unacceptable with respect to the historical production profiles to produce a historical set of quantifications. The historical set of qualifications is input into a genetic program in order to generate a historical proxy. The historical proxy is then applied to the large set of possible reservoir models, and each model of the large set of reservoir models is qualified as either acceptable or unacceptable to identify a set of acceptable reservoir models. For the forecasting or prediction phase of the present invention, a future production profile is generated for each of the initial sample of reservoir models. The initial sample of reservoir models is quantified with respect to the future production profiles to produce forecasting characterizations. The forecasting characterizations are input into genetic programming to generate a forecasting proxy. The forecasting proxy is then applied to the set of acceptable reservoir models from the history matching process to produce a range of production forecasts for the reservoir. The present invention provides a more efficient method of forecasting oil and gas production of reservoirs into the future than the prior art. The present invention is also more accurate than prior art methods. The present invention is able to identify acceptable reservoir models for a given petroleum field from potentially millions of reservoir models in the history matching phase. The present invention is also able to utilize each of those acceptable reservoir models and produce an accurate range of production forecasts for the petroleum reservoir. The present invention greatly increases the degree of confidence than that of prior art methods. The method of the present invention offers further differences over the prior art. Analysis of the production of petroleum reservoir is an ongoing process. As described-above, models are constantly being rerun and further tuned to improve their ability to match newly gathered production data. The present invention is more efficient than the prior art and does not assume any prior function form or model, thus no prior bias need be introduced into the analysis. One embodiment of the present invention improves the accuracy of the computer analysis of production for oil reservoirs by uniformly sampling a dense distribution of reservoir models in an input parameter space. The results of that sampling are used to produce multiple models that accurately match the production data history. Those models are then used to predict future production forecasts. One object of the present invention is to identify the most significant parameters of the reservoir and systematically integrate those parameters into the analysis. Another object of the present invention is to classify the reservoir models that match the historical data of the reservoir. Alternatively, a further object of the present invention is to classify the reservoir models that do not match the historical data of the reservoir. An additional object of the present invention is to identify common characteristics for reservoir models that do match the historical data of the reservoir, and for reservoir models that do not match the historical data. Additional features and advantages of the present invention are described in, and will be apparent from, the following Detailed Description of the Invention and the Figures. BRIEF DESCRIPTION OF THE DRAWINGS These and other objects, features and advantages of the present invention will become better understood with regard to the following description, pending claims and accompanying drawings where: FIG. 1 illustrates a flowchart of the workflow of one embodiment of the present invention; FIG. 2 illustrates a graph of the general workflow of the history matching and forecast phase of an analysis of production for oil reservoirs; FIG. 3 illustrates a uniform design for sampling input parameters in an embodiment of the present invention; FIG. 4 illustrates a flowchart of the workflow of one embodiment of the present invention; FIG. 5 illustrates a 3D structural view of an oil field which was analyzed using an embodiment of the present invention; FIG. 6 illustrates a 3D view of the reservoir compartmentalization of an oil field which was analyzed using one embodiment of the present invention; FIG. 7 illustrates a graph for water oil contact, WOC, compared to the gas oil contact, GOC, for an analysis of an oil field utilizing one embodiment of the present invention; FIG. 8 illustrates a graph for the oil volume, WOC-GOC, compared to the mismatch error, E, for an analysis of an oil field utilizing one embodiment of the present invention; FIG. 9 illustrates a graph for the oil volume, WOC-GOC, compared to the regression output, R for an analysis of an oil field utilizing one embodiment of the present invention; FIG. 10 illustrates a graph for the oil volume, WOC-GOC, compared to the mismatch error, E, for an analysis of an oil field utilizing one embodiment of the present invention; FIG. 11 illustrates a graph for the mismatch error, E, compared to the regression output, R, for an analysis of an oil field utilizing one embodiment of the present invention; FIG. 12 illustrates a graph showing the genetic programming classification results for an analysis of an oil field utilizing one embodiment of the present invention; FIG. 13 illustrates a graph showing one view of the good models which were selected by the historical proxy in an analysis of an oil field utilizing one embodiment of the present invention; FIG. 14 illustrates a graph showing one view of the good models which were selected by the computer simulator in an analysis of an oil field utilizing one embodiment of the present invention; FIG. 15 illustrates a graph showing one view of the good models which were selected by the historical proxy in an analysis of an oil field utilizing one embodiment of the present invention; FIG. 16 illustrates a graph showing one view of the good models which were selected by the computer simulator in an analysis of an oil field utilizing one embodiment of the present invention; FIG. 17 illustrates a graph for the gas injection forecast by the computer simulator compared to the gas injection forecast by the genetic programming proxy in an analysis of an oil field utilizing one embodiment of the present invention; FIG. 18 illustrates a graph for the gas injection forecast on the 63 good models by the computer simulator compared to the gas injection forecast by the genetic programming proxy in an analysis of an oil field utilizing one embodiment of the present invention; FIGS. 19 and 20 illustrate a graph showing the cumulative gas injection in the year 2031 forecasted by the forecasting proxy in an analysis of an oil field utilizing one embodiment of the present invention; and FIGS. 21 and 22 illustrate a graph showing the cumulative gas injection in the year 2031 forecasted by the 63 good models and the computer simulator in an analysis of an oil field utilizing one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION While this invention is susceptible of embodiments in many different forms, there are shown in the drawings, and will herein be described in detail, preferred embodiments of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the broad aspect of the invention to the embodiments illustrated. The present invention allows one to analyze an oil or gas reservoir and provide more reliable future production forecasts than existing prior art methods. The future production forecasts can then be used to determine how to further develop the reservoir. To improve the confidence in the production forecasts of reservoir models, a dense distribution of reservoir models needs to be sampled. Additionally, there needs to be a method for identifying which of those models provide a good match to the production data history of the reservoir. With that information, only good models will be used in the analysis for estimating future production and this will result in a greater degree of confidence in the forecasting results. The present invention accomplishes these goals and one embodiment of the present invention is illustrated in FIG. 1 . The present invention includes producing an initial sample of reservoir models 10 which is related to a plurality of reservoir models. The plurality of reservoir models being much larger than the initial sample of reservoir models. Two sets of data are generated, historical production profiles 12 and future production profiles 22 . The historical production profiles are used to qualify each of the initial sample of reservoir models as either “good” or “bad”, or “acceptable” or “unacceptable” 14 . A historical set of qualifications is then produced 16 , and genetic symbolic regression is sued to construct a history matching proxy 18 . By way of further background, optimization methods known as “genetic algorithms” are known in the art. Conventional genetic algorithms serve to select a string referred to as a “solution vector”, or “chromosome”), consisting of digits (“genes”) having values (“alleles”) that provide the optimum value when applied to a “fitness function” modeling the desired optimization situation. According to this technique, a group, or “generation”, of chromosomes is randomly generated, and the fitness function is evaluated for each chromosome. A successor generation is then produced from the previous generation, with selection made according to the evaluated fitness function; for example, a probability function may assign a probability value to each of the chromosomes in the generation according to its fitness function value. In any case, a chromosome that produced a higher fitness function value is more likely to be selected for use in producing the next generation than a chromosome that produced a lower fitness function value. This is done by first selecting fitter chromosomes from the current generation to build a “reproduction pool”. Pairs of chromosomes are then randomly selected, from the reproduction pool to produce offspring by exchanging “genes” on either side of a “crossover” point between the two chromosomes. Additionally, mutation may be introduced through the random alteration of a small fraction (e.g., 1/1000) of the genes on the new offspring. These new offspring form a new generation of population. Iterative evaluation and reproduction of the chromosomes in this manner eventually converges upon an optimized chromosome. Unlike the known prior art methods of genetic programming, the present invention employs a new variation of genetic algorithms to construct a historical proxy 18 . In the present invention, the genetic programming differs from prior art genetic algorithms in that the chromosome is a mathematical function. The output of the function is used to decide if a reservoir models is an acceptable or unacceptable match to the historical set of qualifications 20 according to the criterion decided by experts. In other words, the historical proxy functions as a classifier to separate “good” models from “bad” models in the parameter space 14 . The actual amount of fluid produced by the reservoir models is not estimated by the historical proxy. This is very different from prior art reservoir simulator proxies which give the same type of output as the full simulator. As illustrated in FIG. 1 , the historical proxy functions as a genetic programming classifier which is used to separate acceptable models from unacceptable models in the plurality of reservoir models 20 . The historical proxy is used to sample a dense distribution of reservoir models in the parameter space (potentially millions of models). Acceptable reservoir models are designated, and those acceptable reservoir models will be used to forecast future production. Since the future production forecast will be based upon such a large number of acceptable reservoir models, the results are more representative and closer to reality than the results of the prior art. In the forecasting phase 36 of the present invention, as shown in FIG. 1 , future production profiles are generated for each of the initial sample of reservoir models 22 . The future production profiles are then used to quantify each of the initial sample of reservoir models 24 to produce forecasting characterizations 26 . Genetic programming utilizes the forecasting characterizations to generate a forecasting proxy 28 . The forecasting proxy is then applied to the set of acceptable reservoir models 30 identified in the history matching phase 34 of the present invention to produce a range of production forecasts 32 . The present invention is thus able to efficiently predict a range of production forecasts with a lesser degree of uncertainty than the prior art. FIG. 2 provides an illustration of the general workflow of the history matching 38 and the forecast phase 40 of the analysis. In this example, the historical data which is used in the history match phase 38 is the Historical Field Oil Production Rate 42 and the Historical Field Oil Cumulative Production 44 . It should be understood that other historical production data can be used other than the two sets of data identified in FIG. 2 . In the history matching phase 38 , models with varying input parameters are run through computer simulations to identify those models which provide acceptable matches with the Historical Field Oil Production Rate 42 . Those models are then used in the forecast phase 40 of the analysis. In the illustration in FIG. 2 , the computer models provide forecast ranges for Field Oil Cumulative Production 46 and Field Oil Production Rate 54 . The forecast range for the Field Oil Cumulative Production 46 is illustrated as P90 48 , P50 50 and P10 52 . Similarly, the forecast range for the Field Oil Production Rate 54 is illustrated as P90 56 , P50 58 and P10 60 . The present invention greatly reduces the uncertainty associated with the analysis by assuring that a larger pool of models are sampled and a larger pool of acceptable models are modified. One embodiment of the present invention utilizes uniform sampling to further reduce the uncertainty with the computer analysis of production for oil reservoirs. FIG. 3 provides an illustration of the uniform sampling method. The uniform sampling generates a sampling distribution 62 that covers the entire parameter space 64 for a predetermined number of runs. It ensures that no large regions of the parameter space 64 are left under sampled. Such coverage is used to obtain simulation data for the construction of a robust proxy that is able to interpolate all intermediate points in the parameter space 64 . One such embodiment of the present invention which utilizes uniform sampling is illustrated in FIG. 4 . Initially, in the history matching phase 66 , reservoir parameters and their value ranges are decided by reservoir experts 70 . The number of simulation runs and the associated parameter values are then determined according to uniform design 72 . With these parameters, the computer simulations in the history matching phase are run 74 . Once the simulations in the history matching phase are completed 74 , the objective function and the matching threshold (the acceptable mismatch between simulation results and production data) are defined 76 . Those models which pass the threshold are labeled as “good” while the others are labeled as “bad” 78 . These simulation results are then used by the genetic programming symbolic regression function to construct a proxy that separates good models from bad models 80 . With this genetic programming classifier as the simulator proxy, a dense distribution of the parameter space can then be sampled 82 . The models that are identified as good are selected for forecasting future production 84 . Forecasting future production of the field also requires computer simulation. Since the umber of good models identified by the genetic programming proxy is normally quite large, it is not practical to make all of the simulation runs with the good models. Similar to the way the simulator proxy is constructed for history matching, a second genetic programming proxy is generated for production forecast. As shown on the right side of FIG. 4 , the simulation results again based on uniform sampling 86 will be used to construct a genetic programming forecasting proxy 88 . This proxy is then applied to all the good models identified in the history matching phase 90 . Based on the forecasting results, uncertainty statistics such as the P10, P50 and P90 are then estimated 92 . The applicants have conducted a case study using one embodiment of the present invention on a large oil field. The subject oil field has over one billion barrels of original oil in place and has been in production for more than 30 years. Due to the long production history, the data collected from the field were not consistent and the quality of the data was not reliable. The oil field in the case study is overlain by a significant gas cap. FIG. 5 shows the oil field 94 and the gas oil contact (“GOC”) line 96 that separates the gas cap from the underneath oil. Similarly, there is a water oil contact (WOC) line 98 that separates oil from the water below. The area 100 between the GOC line 96 and WOC line 98 is the oil volume to be recovered. The field 94 also has 4 geological faults 102 , 104 , 106 , 108 , illustrated in FIG. 6 , which affect the oil flow patterns. Those faults 102 , 104 , 106 , 108 have to be considered in the computer flow simulation. As a mature field 94 with most of its oil recovered, the reservoir now has pore space which can be used for storage. One proposed plan is to store the gas produced as a side product from neighboring oil fields. In this particular case, the gas produced has no economical value and re-injecting it back into the field was one environmental-friendly method of storing the gas. In order to evaluate the feasibility of the plan, the cumulative volume of gas that can be injected (stored) in the year 2031 needed to be evaluated. This evaluation would assist managers in making decisions such as how much gas to transport from the neighboring oil fields and the frequency of the transportation. The cumulative volume of the gas that can be injected is essentially the cumulative volume of the oil that will be produced from the field 94 since this is the amount of space that will become available for gas storage. To answer that question, a production forecasting study of the field 94 in the year 2031 had to be conducted. Prior to carrying out production forecast, the reservoir model has to be updated through the history matching process. The first step is deciding reservoir parameters and their value ranges for flow simulation. Table I below, shows the 10 parameters which were selected. TABLE I Parameters Min Max Water Oil Contact (WOC) 7289 ft 7389 ft Gas Oil Contact (GOC) 6522 ft 6622 ft Fault Transmissibility Multiplier (TRANS) 0 1 Global K h Multiplier (XYPERM) 1 20 Global K ν Multiplier (ZPERM) 0.1 20 Fairway Y-Perm Multiplier (YPERM) 0.75 4 Fairway K v Multiplier2 (ZPERM2) 0.75 4 Critical Gas Saturation (SGC) 0.02 0.04 Vertical Communication (ZTRANS) 0 5 Skin at new Gas Injection (SKIN) 0 30 Among the 10 parameters, 5 parameters are multipliers in log10 scale. The other 5 parameters are in regular scale. The multiplier parameters are supplied to the base values in each grid of the reservoir model during computer simulation. The parameters selected for the computer simulation contain not only the ones that affect the history like fluid contacts (WOC and GOC), fault transmissibility (TRANS), permeability (YPERM) and vertical communication in different areas of the reservoir (ZTRANS), but also parameters associated with future installation of new gas injection wells, such as skin effect. In this way, each computation simulation can run beyond history matching and continue for production forecast to the year 2031. With this setup, each computer simulation produces the flow outputs time-series data for both history matching and for production forecasting. In other words, steps 74 and 86 of FIG. 4 are carried out simultaneously. Based on uniform design, parameter values are selected to conduct 600 computer simulation runs. Each run took about 3 hours to complete using a single CPU machine. Among them, 593 were successful while the other 7 terminated before the simulation was completed. During the computer simulation, various flow data were generated. Among them, only field water production rate (FWPR) and field gas production rate (FGPR), from the years 1973 to 2004, were used for history matching. The other flow data were ignored because the level of uncertainty associated with the corresponding production data collected from the field. FWPR and FGPR collected from the field were compared with the simulation outputs from each run. The “error” E, defined as the mismatch between the two, is the sum squared error calculated as follows: E = ∑ t = 1973 2004 ⁢ ( FWPR_obs i - FWPR_sim i ) 2 + ( FGPR_obs i - FGPR_sim i ) 2 Here, “obs’ indicates production data while “sim” indicates computer simulation outputs. The largest E that can be accepted as a good match is 1.2. Additionally, if a model has an E smaller than 1.2 but has any of its FWPR or FGPR simulation outputs too far away from the corresponding production data, the production data was deemed not to be reliable and the entire simulation record is disregarded. Based on this criterion, 12 data points were removed. For the remaining 581 simulation data, 63 were labeled as good models while 518 were labeled as bad models. It should be appreciated that there are other methods to calculate the error threshold and those are contemplated to be within the scope of the present invention. In this particular embodiment of the present invention, it was discovered that the oil volume (WOC-GOC) had a strong impact on the reservoir flow outputs, hence important to the matching of production data. As shown in FIG. 7 , among the 581 sets of simulation data, all 63 good models have their WOC and GOC correlated; when the WOC was low, its GOC was also low, thus preserving the oil volume. With such a correlation, another variable, named “oil volume” (WOC-GOC) was added to the analysis to the original 10 parameters to conduct history matching and production forecast study. In this analysis, good models had an oil volume within the range of 750 and 825 feet, except one model 120 which had an “oil volume” of 690 feet ( FIGS. 7 & 8 ). In this embodiment of the present invention, an outlier study was performed on the 581 simulation/production data sets due to the poor quality of the production data. The following rationale was used to detect inconsistent production data. Reservoir models with similar parameter values should have produced similar flow outputs during computation simulation, which should have given similar matches to the production data. There should have been a correlation between the reservoir values and the mis-match (E). If this was not the case, it indicated that the data had a different quality from the others and should not have been trusted. Based on that concept, a GP symbolic regression was used to identify the function that describes the correlation. A commercial genetic programming package, Discipulus™ by RML Technologies, Inc., was used in the study. In this software package, some genetic programming parameters were not fixed but were selected by the software for each run. These genetic programming parameters included population size, maximum program size, and crossover and mutation rates. In the first run, one set of values for these genetic programming parameters was generated. When the run did not produce an improved solution for a certain number of generations, the run was terminated and a new set of genetic programming parameter values was selected by the system to start a new run. The system maintained the best 50 solutions found throughout the multiple runs. When the genetic programming was terminated, the best solution among the pool of 50 solutions was the final solution. In this particular embodiment, the genetic program performed a 120 runs and then was manually terminated. In addition to the parameters whose values were system generated, there were other genetic programming parameters whose values needed to be specified by the users. Table II provides the values of those genetic programming parameters for symbolic regression for the outlier study. TABLE II Objective Evolve A Regression To Identify Outliers In Production Data Functions addition; subtraction; multiplication; division; abs Terminals The 10 reservoir parameters listed in Table I and WOC-GOC Fitness MSE ⁢ : ⁢ ∑ n = 1 581 ⁢ ⁢ ( E 4 - R 1 ) 2 581 , R ⁢ ⁢ is ⁢ ⁢ regression ⁢ ⁢ output Selection Tournament (4 candidates/2 winners) The terminal set consists of 11 reservoir parameters, each of which could be used to build leaf nodes in the genetic programming regression trees. The target is E, which was compared to the regression output R for fitness evaluation. The fitness of an evolved regression was the mean squared error (MSE) of the 581 data points. A tournament selection with size 4 was used. In each tournament, 4 individuals were randomly selected to make 2 pairs. The winners of each pair became parents to generate 2 offspring. After the 120 runs, the genetic programming regression contained 4 parameters: WOC-GOC, TRANS, YPERM and SGC. Among them, WOC-GOC was ranked as having the most impact on the match of production data. FIG. 9 shows the relationship between WOC-GOC and the regression output R. From FIG. 9 , it is evident that 17 of the data points did not fit into the regression pattern. Those 17 data points also had similar outlier behavior with regard to E ( FIG. 10 ). That behavior evidenced that the 17 production data points were unreliable and were removed from the data set. After the outliers were removed, the final data set to construct the simulator proxies consisted of 564 data points; 63 were good models and 501 were bad models as illustrated in FIG. 11 . The outlier study was then completed. The next step in the history matching phase of the analysis was to construct the reservoir simulator proxy or the historical proxy which qualified the reservoir models as good or bad. For this step, the final set of 564 data points were used to construct the genetic programming classifier. Each data point contained 4 input variables (WOC-GOC, TRANS, YPERM and SGC), which were selected by the genetic programming regression outlier study, and one output, E. With the number of bad models 8 times larger than the number of good models, the data set was very unbalanced. To avoid the genetic programming training process generating classifiers that biased bad models, the good model data was duplicated 5 times to balance the data set. Moreover, the entire data set was used for training, instead of splitting it into training, validation and testing, which is the normal practice to avoid over-fitting. This was again because the number of good models was very small. Splitting them further would have made it impossible for the genetic program to train a proxy that represented the full simulator capacity. The genetic programming parameter setup for this analysis was different from the setup for the outlier study. In particular, the fitness function was not MSE. Instead, it was based on hit rate: the percentage of the training data that were correctly classified by the regression. Table III includes the genetic programming system parameter values for symbolic regression for the historical proxy. TABLE III Objective Evolve A Simulator Proxy Classifier For History Matching Functions addition; subtraction; multiplication; division; abs Terminals WOC-GOC, TRANS, YPERM, SGC Fitness Hit rate then MSE Selection Tournament (4 candidates/2 winners) As described-above, the cut point for this particular embodiment for E for a good model was 1.2. When the regression gave an output R less than 1.2, the model was classified as good. If mis-match E was also less than 1.2, the regression made the correct classification. Otherwise, the regression made the wrong classification. A correct classification is called a hit. Hit rate is the percentage of the training that are correctly classified by the regression. There are cases when two regressions may have the same hit rate. In this particular embodiment, the MSE measurement was used to select the winners. The “tied threshold” for MSE measurement was 0.01% in this work. If two classifiers were tied in both their hit rates and MSE measurements, a winner was randomly selected from the two competitors. Also, in this particular embodiment of the present invention, instead of the 11 reservoir parameters being utilized to construct the historical proxy, only the 4 reservoir parameters identified by the outlier study to have impacts on fluid flow were used as terminals to construct the historical proxy. The genetic program completed 120 runs. The regression that had the best classification accuracy at the end of the run was selected as the historical proxy for the simulator. The classification accuracy of the chosen historical proxy was 82.54% on good models and 85.82% on bad models. The overall classification accuracy for the historical proxy was 85.82%. FIG. 12 illustrates the classification results in the parameter spaced defined by WOC-GOC, YPERM and TRANS. FIG. 12 shows that the models with WOC-GOC outside the range of 750 and 825 feet were classified as bad models. Models, however, within that range could be either good or bad depending on other parameter values. The historical proxy was then used to evaluate new sample points in the parameter space. For each of the 5 parameters (GOC-WOC was treated as two parameters), 11 samples were selected, evenly distributed between their minimum and maximum values. The resulting total number of samples was 11 5 =161,051. The historical proxy was applied to those samples and 28,125 models were identified as good models while 132,926 models were classified as bad models. FIG. 13 illustrates the 28,125 good models in the 3D parameter space defined by WOC-GOC, TRANS and SGC. The pattern is consistent with that of the 63 good models identified by computer simulation which is illustrated in FIG. 14 . Within the 3D parameter space defined by WOC-GOC, YPERM and TRANS, the good models have a slightly different pattern as shown in FIG. 15 . Yet the pattern is also consistent with the pattern of the 63 good models identified by computer simulation as illustrated in FIG. 16 . Those results indicated that the genetic programming classifier was a reasonable high-quality proxy for the full reservoir simulator. The 28,125 good models were then considered to be close to reality. Those models revealed certain reservoir characteristics for this particular oil field. They YPERM value was greater than 1.07. The faults separating different geo-bodies were not completely sealing, the transmissibility was non-zero. The width of the oil column (WOC-GOC) was greater than 750 feet. The 28,125 good models were then used in the production forecast analysis. The forecast for oil production (or the volume of gas injection) also requires computer simulation. It was not practical to make simulation runs for all 28,125 good models, thus a second proxy was also warranted for this phase of the analysis. In this phase, all 11 reservoir parameters were used to construct the forecasting proxy. The target forecast (F) for this embodiment of the present invention was the cumulative volume of gas injection for the year 2031. The initial 581 data points were divided into three groups: 188 for training, 188 for validation and 188 for blind testing. Training data was used for the genetic program to construct the regression proxy while the validation data was used to select the final regression or the forecasting proxy. The evaluation of the regression proxy was based on its performance on the blind testing data. The genetic programming parameter set up is set forth in Table IV. TABLE IV Objective Evolve A Simulator Proxy For Production Forecast Functions addition; subtraction; multiplication; division; abs Terminals The 10 reservoir parameters listed in Table I and WOC-GOC Fitness MSE ⁢ : ⁢ ∑ n = 1 188 ⁢ ⁢ ( F 1 - R 4 ) 2 188 , F ⁢ ⁢ is ⁢ ⁢ simulator ⁢ ⁢ forecast Selection Tournament (4 candidates/2 winners) The genetic program was allowed to make 120 runs and the regression with the smallest MSE on validation data was selected as the forecasting proxy. Table V below lists the R 2 and MSE on the training, validation and blind testing data. TABLE V Data Set R 2 MSE Training 0.799792775 0.001151542 Validation 0.762180905 0.001333534 Testing 0.7106646 0.001550482 All 0.757354092 0.001345186 As the forecasting proxy was to make predications for the next 30 years, a R 2 in the range of 0.76 was considered to be acceptable. FIG. 17 illustrates the cross-lot for simulator and proxy forecasts on the 581 simulation models. Across all models, the forecasting proxy gave consistent prediction as that by the computer simulator. Forecasting on the 63 good models is illustrated in FIG. 18 . In this particular case, the forecasting proxy gave a smaller prediction range (0.12256) than that by the simulator (0.2158). Similar to the history-matching proxy in this embodiment, WOC-GOC was ranked to have the most impact on production forecasts. The forecasting proxy was then used to derive gas injection production predictions from all good models identified by the by the historical proxy. Since each model selected by the historical proxy was described 6 reservoir parameter values, there was freedom in selecting the values of the other 5 parameters not used by the historical proxy. Each of the 5 unconstrained parameters was sampled by selecting 5 points, evenly distributed between their minimum and maximum values. Each combination of the 5 parameter values was used to complement the 6 parameter values in each of the 28,125 good models to run the forecasting proxy. This resulted in a total of 87,890,625 models being sampled with the forecasting proxy. FIGS. 19 and 20 provide the cumulative gas injection for the year 2031 which was forecasted by the models. As shown, the gas injection range between 1.19 million standard cubic feet (MSCF) and 1.2 MSCF is predicated by the largest number of reservoir models (22% of the total models). This is similar to the predictions by the 63 computer simulation models a illustrated in FIGS. 21 and 22 . The cumulative density function (CDF) of the forecast proxy gave a P10 value of 1.06, a P50 value of 1.18 and a P90 value of 1.216 MSCF. This meant that the most likely (P50) injection volume would be 1.18 MSCF. There was a 90% probability that the injection would be higher than 1.05 MSCF (P10) and a 10% probability that the injection would be lower than 1.216 MSCF (P90). This uncertainty range allows for better management in preparing for gas transportation and plan for other related arrangements. While in the foregoing specification this invention has been described in relation to certain preferred embodiments thereof, and many details have been set forth for purpose of illustration, it will be apparent to those skilled in the art that the invention is susceptible to alteration and that certain other details described herein can vary considerably without departing from the basic principles of the invention.

A method utilizing genetic programming to construct history matching and forecasting proxies for reservoir simulators. Acting as surrogates for computer simulators, the genetic programming proxies evaluate a large number of reservoir models and predict future production forecasts for petroleum reservoirs.

BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to an adsorber element for a heat exchanger, which contains as a central component a heat-conducting solid body, on the surface of which a sorption material for a vaporous adsorbate and on the outer surface of which a fluid-tight foil, or composite film, is arranged.The invention further relates to an adsorption heat pump or adsorption refrigerator that contains at least one adsorber element of this type. 2. Description of Background and Other Information With many technical adsorption processes, the power with which the adsorption heat can be removed via a heat exchanger plays an important role. This applies analogously to the heat transfer efficiency in heating the adsorbent via a heat exchanger for the desorption/reconditioning of the adsorbent (usually referred to below as sorption material). These power characteristics are of central importance for adsorption heat pumps and adsorption refrigerators and related adsorption applications in energy and climate control technology. Various companies, e.g., Vaillant, UOP, Mitsubishi and SorTech, are currently working intensively on concepts for adsorption heat pumps and adsorption refrigerators to increase the power density related to the construction volume. In physical terms, this hereby relates to the problem of optimizing the heat and matter transfer in the heat pump. In a microporous solid (adsorbent/sorption material, e.g., a zeolite or a silica gel) the vapor of the working fluid (adsorbate, e.g., water, methanol or ammonia) is adsorbed, wherein heat is released. For an improved adsorber element, therefore, a good thermal link of the microporous adsorbent/sorption material (e.g., a zeolite) to a heat-exchanger surface or to a heat transfer fluid flowing on the other side of this boundary layer is necessary. DE 10 2005 037 708 A1 and DE 10 2005 037 763 A1 describe a compact structure, with which an improved heat transfer is achieved from the heat exchanger plate to the heat transfer fluid. This is achieved either by means of a cylindrical heat exchanger or by means of a plate heat exchanger in which the heat transfer fluid flows through channels in the heat exchanger plate. DE 101 19 258 A1 describes an adsorber structure in which the adsorbent is placed on the fins of a finned tube in one layer in the form of granules. A better thermal contact of the sorption material to the heat exchanger can be obtained with a structure according to U.S. Pat. No. 6,102,107. The adsorber is hereby designed as a fin coil heat exchanger, that is as a bundle of parallel plates that are pushed through a tube bundle in a perpendicular manner. The heat transfer fluid flows in the tubes and the sorption material is applied to the plates as a layer on both sides. The sorption material is hereby bonded in a polymer foil. With an adsorber design of this type a good thermal link of the sorption material to the heat exchanger surface can be obtained such that the heat transfer to the heat transfer fluid in the heat exchanger becomes the limiting factor for the achievable power density of the heat pump. Through an adsorber design of this type, however, the power densities are not yet achieved that are required for certain applications (e.g., for car air-conditioning). In order to further increase the power density of adsorption heat pumps and, at the same time, to render possible a high efficiency (COP, performance factor), new concepts are necessary for the design of the adsorber. The (thermal) COP (Coefficient of Performance) for a refrigerator is understood to be the ratio of useful cold obtained and the driving heat required for this; for a heat pump the COP is defined as the ratio of the useful heat obtained (at the average temperature level) to the driving heat (at high temperature level). For practical application additionally a consideration of the overall energy expenditure is necessary, including the electric consumption of pumps, etc. A problem in addition to the above-referenced problems is the limitation of the adsorption speed by the transport of the gaseous and/or vaporous adsorbate to the micropores or mesopores of the solid sorption material, where the adsorption heat is released. This problem occurs in particular with adsorbates with low vapor pressure, such as, e.g., water or methanol. In particular with thick layers of the sorption material, a high diffusion barrier results for the adsorbing gas, depending on the structure of the layer. According to WO 02/45847 one solution approach is to achieve a sufficient vapor-permeability of the sorption material layer by bonding the sorption material micro-particles into a vapor-permeable polymer matrix with good thermal conductivity. DE 101 59 652 C2 describes the insertion of sorption material into a foam-like matrix of metal. Another approach to a solution—at least for zeolite sorption materials—is described in L. G. Gordeeva et al. “Preparation of Zeolite Layers with Enhanced Mass Transfer Properties for Adsorption Air Conditioning” in Proc. of the Int. Sorption Heat Pump Conf. ISHPC, Shanghai, China, Sep. 24-27, 2002. Here, a suitable pore former is added during the synthesis of the sorption material layer, which is subsequently burnt out or washed out, in order to create additional channels for the vapor transport. SUMMARY OF THE INVENTION The present invention overcomes the disadvantages of the prior art and is directed to an adsorber element with which the heat being released during adsorption can be efficiently dissipated and the heat necessary in desorption can be easily added. In addition, the invention provides a heat pump or refrigerator that contains several adsorber elements according to the invention in an arrangement that likewise renders possible an efficient dissipation or addition of heat and in addition an efficient heat recovery between several identical or similarly constructed adsorbers. Furthermore, the invention provides for an adsorber element and a heat pump or refrigerator in which a highest possible COP can be established and in particular the thermal mass (heat capacity) of the carrier structure for the sorption material and the other components of the heat exchanger is as low as possible so that the greatest possible ratio of the sorbate heat transformation to sensible heat transformation can be achieved via the adsorption cycle. In summary, the invention encompasses an adsorber element, an adsorption heat pump, and an adsorption refrigerator, as well as additional advantageous developments. According to the invention, it has been recognized that a reduction in the heat transmission resistances in the adsorber and at the same time a reduction of the thermal mass of the heat exchanger is possible if the adsorber element is based on a heat-conducting solid body, on the boundary layer of which to the heat transfer fluid a fluid-tight, composite film, hereafter foil composite, is arranged.The heat-conducting solid body can then have a desired structure or the sorption material can be arranged thereon in any desired manner, since the foil composite takes over the function of acting as a boundary layer between heat transfer fluid and solid body coated with sorption material. The adsorber element according to the invention thus comprises a heat-conducting solid body, on the surface of which a sorption material for a vaporous adsorbate is arranged, and on the outer surface of which in the areas in which a contact with a heat transfer fluid is provided or takes place, a fluid-tight foil composite is arranged that is connected to the heat-conducting solid body positively, non-positively or by adhesive force. According to the invention, the outer surface of the heat-conducting solid body is to be understood as meaning the area of the solid body surface in which a contact of the solid body with a heat transfer fluid (via the fluid-tight foil composite) is provided or takes place. The adsorber element is furthermore embodied such that the heat exchange between the heat-conducting solid body and the heat transfer fluid can take place via this foil composite and, according to a particular embodiment, exclusively or at least essentially exclusively. The fluid-tight foil composite has at least one metal layer or a layer of a material that is heat conducting at least in the perpendicular orientation to the layer, and at least one other layer that is a base layer or a sealing layer. The metal layer contained in the foil composite or the layer of the heat conducting material (e.g., a heat-conducting polymer that can contain, e.g., metal particles or carbon, e.g., in the form of nanotubes) in perpendicular orientation to the layer, ensures in particular that vacuum tightness is given and that it is ensured that the areas in which the heat transfer fluid and the adsorbate are located are separated from one another in a fluid-tight manner. The metal layer, in a particular embodiment, is a layer that comprises aluminum and/or copper or contains aluminum and/or copper. In a particular embodiment, the metal layer is so thick that a thermal conductivity of the foil composite perpendicular to the foil plane is given (such as, e.g., a heat conductivity of at least 0.2 W m −1 K −1 or, in particular variation, at least 2 W m −1 K −1 ; the thermal conductivity is always determined according to the invention via the thermal diffusivity with the laser-flash method); for this the thickness of the layer should be at least in the μm range and in particular be greater than 1 μm. If the foil composite is not wetted by the heat transfer fluid over the entire area, the layer should be thick enough that it can also contribute appreciably to the heat transfer along the foil; the thermal conductivity along the layer should then be, in a particular embodiment, at least 20 W m −1 K −1 . In order that barrier properties of the foil composite can also be ensured (and the foil composite can be applied onto the heat-conducting solid body by means of a vacuum packing method), this metal layer must be pore-free and must have a thickness of at least 12 μm, or, in a particular embodiment, at least 15 μm. The sealing layer serves to render possible a connection (in particular welding or adhesion) of the ends of the foil composite so that vacuum tightness or seal tightness is given with respect to the heat transfer fluid. However, it is also possible to omit the sealing layer and to achieve the connection of the foil ends, e.g., by means of a sintering method. The welding of the foil ends can be carried out by means of conventional foil-welding methods, e.g., thermally (sealing layers of polyethylene or polypropylene are suitable for this in particular) or by means of ultrasound (also with foil composites without a sealing layer) or microwaves (also with foil composites without a sealing layer). The sealing layer is usually arranged as outermost layer on one or on both sides of the foil composite. This has the advantage that easy connection of the foil ends is possible. In this case the base layer should not then comprise a material that can swell by contact with the adsorbate (in particular if methanol is used as the adsorbate), or that permits laminating adhesive between the layers of the foil composite to be dissolved or partially dissolved through diffusing adsorbate. According to the invention the sealing seam strength of the sealing seams should be at least 25 N/15 mm or, in a particular embodiment, 50 N/15 mm (measured according to leaflet 33 of Fraunhofer IVV “Bestimmung der Festigkeit von Heiβsiegelnähten—Quasistatische Methode”) so that long-term stability is also ensured with the use of the adsorber elements in environments with high mechanical stress (e.g., in the engine compartment of a motor vehicle). The thickness of the sealing layer to produce sealing seams of this type should be at least 30 μm and, in a particular embodiment, at least 50 μm. Compared to metal sheets as boundary layer between heat transfer fluid and solid body with sorption material, a foil composite with a sealing layer has the advantage that the vacuum-tight separation from heat transfer fluid and sorption material can be achieved with substantially lower production expenditure. Furthermore, corrosion problems are avoided, which in the case of the connection of metal sheets could occur through soldering processes. The foil composite can be additionally stabilized by means of a base layer. In particular the breaking strength of the foil composite can thus be ensured and the mechanical stability thereof increased (i.e., in particular render possible a protection against damage and injury). The base layer, according to particular embodiments, comprises polyamide, polyethylene terephthalate, or a fluorine-containing polymer or contains one of these materials. The material of the base layer, in a particular embodiment, is selected such that the base layer contributes to the vacuum tightness of the foil composite. Furthermore, in a particular embodiment, the base layer contains additives that increase the thermal conductivity of the base layer (e.g., carbon). The base layer is frequently arranged on the side of the foil composite facing away from the outside of the heat-conducting solid body, in particular as the outermost layer or as a layer arranged under an outermost sealing layer. In this case the base layer should not comprise a material that can swell through contact with the heat transfer fluid or that permits the laminating adhesive between the layers of the foil composite to be dissolved or partially dissolved through the heat transfer fluid. The foil composite should have a base layer if there is a danger of injury from the heat-conducting solid body (in particular by perforation). This danger of injury depends on the mechanical stress of the adsorber elements and can occur in particular with open-pore heat-conducting solid bodies. The thickness of the base layer should then be at least 10 μm. In a particular embodiment, the foil composite has at least one metal layer, at least one sealing layer and at least one base layer. A sealing layer is frequently arranged on one side of the metal layer and a base layer on the other side. The layers are usually connected to one another by means of a suitable laminating adhesive or binder. In order to ensure long-term durability, the temperature stability of each individual layer of the foil composite should be given (in particular at above 100° C. or, in a particular embodiment, also above 120° C.). In order to ensure the delamination resistance, the interlayer adhesion of the foil composite should be at least 3 N/15 mm or, in a particular embodiment, 4 N/15 mm (the interlayer adhesion is tested based on the IVV leaflet 5 “Prüfung wachskaschierter Verbundpackstoffe aus Papieren und/oder Folien—Messung der Spaltfestigkeit”). The mechanical stability of the foil composite should be designed in the case of high mechanical stress on the adsorber element, in particular with the use of open-pore heat-conducting solid bodies, such that the foil composite cannot be damaged by the solid body. A puncture strength of greater than 6 N or, in a particular embodiment, greater than 12 N should therefore be given, if no after-treatment (in particular smoothing) of the open-pore solid body is to be carried out. The puncture strength is tested according to DIN EN 14477. The foil composite used according to the invention ensures that the heat transfer fluid cannot come into contact with the sorption material. On the other hand, by using a foil composite it is ensured that the boundary layer between heat transfer fluid and heat-conducting solid body is very thin and therefore an efficient heat exchange from the solid body to the heat transfer fluid can take place. The adsorber elements according to the invention furthermore have the advantage that the foil composites contained therein have a low thermal mass so that with good sorptive/sensible heat ratio short thermal paths can be achieved from the sorption material to the heat transfer fluid. The thermal mass is much lower than with metal sheets, such as are known, e.g., from plate heat exchangers, so that the expansion of the heat-conducting solid body perpendicular to the contact surface with the foil composite can be considerably reduced. Nevertheless, the ratio of sorptive heat transformation to sensible heat transformation can be achieved as with the use of a metal sheet as a boundary layer. The application of findings from microsystem technology and microfluidics regarding the intensification of the heat transfer and mass transport in adsorbers of heat pumps is therefore rendered possible through the use of a foil composite. Usually the fluid-tight foil composite will therefore be connected flat to the heat-conducting solid body, wherein a connection by adhesive force is not necessary, however. The fluid-tight foil composite can also be (but does not have to be) arranged, e.g., in tubular channels that pass through the heat-conducting solid body. The use of a foil composite makes it possible to minimize the thickness of the boundary layer between the heat transfer fluid and the heat-conducting solid body, since by using a metal layer (or a layer of the heat-conducting material in perpendicular orientation to the layer) and a base layer or a sealing layer the mechanical stability can be increased and the processability can be improved. However, at the same time the greatest possible flexibility exists regarding the surface structures flowed around or flowed through by the heat transfer fluid and also regarding the arrangement of the structures that are to be flowed through by the heat transfer fluid. In a particular embodiment, the foil composite should be so flexible that it clings to the surface of the solid body upon the application of a vacuum, so that grooves present on the surface or optionally also pores with a diameter of greater than 0.5 mm already exhibit a flat contact between the surface of the grooves or surface of the pores of the solid body and the fluid-tight foil composite. It also has been recognized according to the invention that the thermal mass of the heat transfer medium can be reduced (in favor of a higher COP) if instead of a mechanical stability with respect to the pressure of the heat transfer fluid of the boundary surface between the heat transfer fluid and the solid body/sorption material over the entire area of the boundary surface, a mechanical stability is required only in those areas in which the boundary surface is not directly located on the outer surface of the solid body (e.g., with open-porous solid bodies a mechanical stability on the surface scale of the pores of the open-porous structure). In this case the heat-conducting solid body takes over the function of the mechanical stabilization or the pressure difference between the heat transfer fluid and the vapor pressure of the vaporous adsorbate. The arrangement according to the invention furthermore has the advantage that a fluid-tight foil composite can be easily connected to the heat-conducting solid body, and remains on the surface of the solid body during the operation of the heat exchanger even without additional auxiliaries, as long as a negative pressure (relative to the fluid side) is present on the solid body side (such as, for example, with heat exchangers that operate with vaporous water or methanol as adsorbate), or a positive pressure (relative to the adsorbent side) is present on the fluid side. Furthermore, the arrangement has the advantage that the foil can be removed and replaced easily (e.g., in the event of material fatigue of a component of the heat exchanger or in the recycling of the heat exchanger). Materials that are vacuum tight are therefore used, in a particular embodiment, include foil composite. Furthermore, the foil composite should be permanently stable in the temperature range usually provided for the application (such as, in a particular embodiment, above 100° C. or, in another particular embodiment, above 120° C.). The fluid-tight foil composite is usually arranged in the adsorber element according to the invention such that the heat transfer fluid flows around the heat-conducting solid body only on the outer surface thereof and cannot flow through the solid body or only to a slight extent in the form of tubular or channel-like forms. However, in individual cases, the latter can be useful. The ratio of the sorptive heat transformation to the sensible heat transformation of the adsorber element according to the invention is greater than 2.5, in a particular embodiment or, in a variation, greater than 5. The influence of this heat ratio on the efficiency (COP) depends decisively on the degree of the heat recovery achieved. With very good internal heat recovery, a poorer sorptive/sensible heat ratio is acceptable than with poorer heat recovery (particularly in this case it is also acceptable to fall below the value of 2.5). In order to achieve a compact construction and a high power density of the heat pump, the average heat transmission resistance from the adsorbent to the heat transfer fluid should be so small that cycle times of less than 10 minutes can be achieved or, in a particular embodiment, less than 5 minutes or, in a variation, less than 3 minutes. The heat-conducting solid body is at least in part an open-pore solid body, according to a particular embodiment. According to the invention this includes any material that ensures that the vaporous adsorbate used (in particular water and/or methanol or optionally also ammonia) can not only flow around the outer surface of the solid body, but can also flow through an existing inner surface of the solid body. In a particular embodiment of the invention, the open-pore solid body should have an effective thermal conductivity of greater than 2 W m −1 K −1 or, in a variation, greater than 6 W m −1 K −1 (in particular in the direction perpendicular to its contact surface with the foil composite). In a particular embodiment, the open-pore solid body should have a porosity >70% and thereby at the same time an effective thermal conductivity of greater than 8 W m −1 K −1 (in particular in the direction perpendicular to its contact surface with the foil composite). According to the invention an open-pore solid body generally means any open-porous structure that has a pore volume accessible by diffusion for a gas of at least 20% relative to the total volume (bulk volume) of the solid body. In an advantageous embodiment the open-pore solid body is a metal foam (or metallic sponge) or a fibrous material. It has been recognized according to the invention that with an adsorber element on the basis of an open-porous solid body, the sorption material is contained in a mechanically stable matrix with good thermal conductivity. This matrix is frequently additionally stabilized by the fluid-tight foil composite. With adsorber elements of this type that have a large surface (in particular relative to the inner surface) compared to the volume, a higher total heat transfer value to the heat transfer fluid (or a shorter “thermal path”) can be realized (due to the porous solid body structure and the much larger contact surface to the heat transfer fluid compared to a tube bundle). According to the invention, it has been further recognized that the combination of power density and efficiency (COP) can additionally be improved through the use of open-pore solid bodies. If one of these two parameters is worse compared to the prior art, this effect will always be overcompensated by an increase of the other parameter. However, both parameters are often increased compared to the prior art. The portion of sensible heat can be reduced compared to the solutions conventionally proposed according to the prior art. The open-porous solid body has a specific surface that is at least twice as large (usually even five times as large) for example compared to fin coil heat exchangers according to the prior art, whereby thinner adsorbent layers and shorter thermal paths are possible. The disadvantage of any higher thermal mass is thereby overcompensated. (The thermal paths are shorter according to the invention compared to those with a fin coil heat exchanger above all because with the fin coil heat exchanger the heat has to be emitted to tubes, which cannot be laid as densely as desired and which have to be connected to one another individually. The fluid-tight foil composites used according to the invention, however, permit a much larger specific contact surface to the heat transfer fluid.) A quicker heat transfer is possible due to a high thermal conductivity of the adsorber element according to the invention; furthermore, a very close coupling of the adsorber to a heat transfer fluid in an external hydraulic circuit can be realized, which is to be circulated with the lowest possible consumption of outside energy. The improved COP is to be attributed with the current invention on the one hand to an improved heat recovery (in particular with the use of the adsorber elements in an arrangements that renders possible a “thermal wave”), and on the other hand to an improved ratio of mass of the sorption material to the heat exchanger mass. According to the prior art (e.g., WO 02/45847) it has been attempted to adjust this mass ratio by the thickest possible layers of sorption material; however, this results—depending on the structure of the layer—in a high diffusion barrier for the gas to be adsorbed and frequently also to a stability problem of the layer or of the composite of sorption material and heat exchanger (on the one hand because of the positive pressure that builds up due to diffusion barriers in the desorption in the lowest ply of the layer, on the other hand due to the different thermal coefficients of expansion of sorption material and heat exchanger and the rapid thermal cycling of this composite). According to the invention, however, it has been recognized that through an application of sorption material onto the inner surface of an open-pore heat-conducting solid body, the mass of the sorption material can be increased and at the same time a small layer thickness can be adjusted. An improved heat recovery can be achieved with the adsorber elements according to the invention in particular if the length of the flow channels of the heat transfer fluid (in the flow direction) is very great compared to the thickness of the adsorber element (perpendicular to the plane of the flow or the foil composite). The thermal conduction in the solid body in the flow direction of the fluid is then of low importance and the prerequisites for realizing a thermal wave (which permits a good heat recovery) are given. If the length of the flow paths are to be further increased in order to improve the efficiency of the thermal wave, this is easily possible with the adsorber elements according to the invention in that several thereof are flowed through serially. In one variant respectively two halves of the open-porous solid body are embodied such that they can take over the function of the spacer, which ensures an unobstructed inflow of the vaporous adsorbate or the provision of a transport structure that can be flowed through well. To this end, for example channels or a wave structure can be embossed in the side of the respective half of the open-porous solid body facing away from the foil composite such that flow channels remain free when adjacent elements of the open-porous solid body bear against one another. A sufficient mechanical stability of the open-porous solid body (i.e., sufficiently large support surfaces) must thereby always be ensured with respect to the positive pressure of the heat transfer fluid. In an alternative embodiment of the invention, instead of respectively two halves that bear against one another, only one solid body can be used that has a sandwich structure. In this sandwich structure a “transport layer” is located in the center that has a lower flow-through resistance than the two “stabilizing layers” on the outside. In general in this embodiment, the “stabilizing layers” will have a higher specific surface area, a higher thermal conductivity, and a lower porosity than the “transport layer.” The production of a sandwich structure of this type can be managed particularly advantageously using short metallic fibers of varying length and thickness, in particular melt-extracted short metallic fibers. The fluid-tight foil composite is then arranged respectively on the sides of the “stabilizing layers” of the sandwich element facing away from the transport layer. The adsorbent (or sorption material; e.g., a zeolite, silicoaluminophosphate (SAPO) or a silica gel) can be applied in different ways onto the surface of the open-pore or non-open-pore heat-conducting solid body or introduced into the porous solid body structure. A particular variant is the crystallization of zeolites by a consumptive method. When an aluminum-containing open-pore solid body (for example, an aluminum sponge) is used, this can serve as an aluminum source of the zeolite synthesis (cf. F. Scheffler et al. in: Preparation and properties of an electrically heatable aluminum foam/zeolite composite, Microporous and Mesoporous Materials 67, 2004, p. 53-59). Furthermore, a crystallization can take place by the “thermal gradient” method (cf. A. Erdem-Senatalar et al. in: Preparation of zeolite coatings by direct heating of the substrates, Microporous and Mesoporous Materials 32, 1999, p. 331-343). Moreover a coating with adsorbent can take place by dipping into a suspension containing the adsorbent. Moreover—in the case of heat-conducting open-pore solid bodies—additionally (or optionally also exclusively) a filling of the (remaining) cavities with further sorption material can take place. If the sorption material is arranged on the outer surface of the heat-conducting solid body, it is also conceivable to use a paper layer coated with the sorption material, as is described in U.S. Pat. No. 6,973,963 B2 (especially the passage from column 4, line 51 through column 5, line 21, which is referenced herewith in its entirety and which belongs to the disclosure of this protective right). The aim is always to achieve the greatest possible mass fraction of the adsorbent in the adsorber element and at the same time to ensure both a very good heat conduction from the adsorbent to the outer surface of the adsorber element (i.e., to the fluid-tight foil composite) as well as to enable a rapid diffusion of the vaporous adsorbate into the total volume of the adsorber element. In particular when the mass transfer (that is, the diffusion of the adsorbate vapor to the adsorbent) becomes the limiting factor for the adsorption kinetics of an adsorber element cooled from outside, as can be the case, e.g., due to the subsequent penetration of granular adsorbent, it is wise to provide the adsorber element specifically with channels for the vapor transport. The heat-conducting solid body according to the invention can also have a layer of the sorption material on its outer surface (in the areas in which—via the fluid-tight foil composite—no contact with the heat transfer fluid is provided). In the case of non-open-pore solid bodies, this is the only arrangement possibility of the sorption material; if the heat-conducting solid body is open-pore, the sorption material can be arranged on its inner and/or outer surface. Outer surface is to be understood hereby to mean the surface of the solid body that is not an inner surface, i.e., in particular is not formed by the pores of the solid body. If the heat-conducting solid body carries a layer of the sorption material on its outer surface, this outer surface (in particular in the area of the coating), in a particular embodiment, is structured in such a way that this structured outer surface is greater by at least a factor of 1.4 than the plane of the corresponding flat body forming the outer surface. If, for example, a flat surface is replaced by a surface in which parallel grooves are embossed into this surface, which grooves have a cross section in the shape of a saw profile in which each “sawtooth” has the shape of an equal-sided, right-angled triangle, this factor is about 1.41. The structured outer surface therefore resembles in particular the surface structure of corrugated cardboard; the cross-section through a surface structured in this way gives in particular a saw profile, a right-angle profile, a sinus profile, or the like. Surface-enlarged structures, e.g., by means of fiber structures or powder structures that can be sintered, welded, or soldered with the surface of the solid body, can also be applied on the outer surface. The geometry of the structured surface is generally not essential; rather, it is essential that the increase in surface is maximized in comparison with the unstructured plane. The fluid-tight foil composite can be connected to the heat-conducting solid body by adhesive force, in that, for example, an adhesive force connection takes place by means of a binder (in a particular embodiment, a binder is selected here that has a high thermal conductivity, e.g., a binder therefore that contains finely dispersed metal particles, carbon or other particles that ensure a sufficient thermal conductivity) or in that the foil composite is sintered onto the heat-conducting solid body (as an example, the sintering onto a metallic solid body is to be named here, in which a foil composite is used that contains a metal layer comprising copper, facing the solid body). A foil composite connected to the heat-conducting solid body by adhesive force has the advantage that it retains the shape, clinging to the heat-conducting solid body under all pressure conditions. The foil composite can also be applied onto the open-pore solid body by means of a vacuum-packing method. As vacuum-packing methods for applying the fluid-tight foil composite to the heat-conducting solid body, in principle all commercially available methods (e.g. food packaging methods) are conceivable according to the invention. Alternatively, the foil composite can be applied onto a—in particular open-pore—solid body, in that the foil composite is arranged (e.g., in a cavity) such that it corresponds at least partially to the outer shape of the heat-conducting solid body. The heat-conducting, in particular open-pore solid body or a preceding stage thereof (e.g., loose or already partially sintered metal fibers, in particular also fibers that contain copper) can then be arranged on the foil composite arranged in this way. Subsequently, the foil composite and the heat-conducting, in particular open-pore solid body or a preceding stage thereof can be connected together by adhesive force (e.g., by means of a sintering method), so that the heat-conducting, in particular open-pore solid body is formed at the latest by means of this connection. Subsequently or alternatively the foil composite or the ends of the foil composite (as soon as the sorption material is also contained) can be sealed, so that a shape-stable adsorber element is formed. On the one hand, the foil composite can be applied directly onto the heat-conducting solid body, in particular if the design principle is orientated to the fact that the fluid-tight foil composite is understood primarily as a boundary for the adsorbate/adsorbent/heat-conducting solid body structural unit. In this case several adsorber elements can then be arranged so that the heat transfer fluid can flow around them in any arrangement. Alternatively, the foil composite can have a geometric shape like a cuff or a tube in particular when the design principle is orientated to the fact that the fluid-tight foil composite is primarily understood as a boundary for the heat transfer fluid structural unit. In this case the geometric shape of the foil composite is stipulated such that one or more partial areas of the foil composite thus present can be connected to the outer surface of the heat-conducting solid body positively, non-positively or by adhesive force. A foil composite that has a geometric shape like a tube or a cuff, is hereby understood in particular to mean that either two facing (cut) edges of a (e.g., right-angled) layer of a foil composite are connected (e.g., sealed) to one another such that a tube-like or cuff-shaped structure is formed or that two layers of the foil composite arranged on top of one another corresponding together to two facing sides are connected respectively (e.g., sealed) at the (cut) edges lying on top of one another. Such a design principle has the advantage that the volume of heat transfer fluid used can be minimized (in contrast, the area of the fluid-tight foil composite can be maximized in the preceding variant). For example, a channel structure can be embossed on the outer surface of a first heat-conducting solid body, which channel structure leads to a flowing-through of the entire area of the tube-shaped or cuff-shaped foil composite with low pressure loss. Usually a foil composite embodied in this way is inserted or clamped between the outer surface of the first heat-conducting solid body and the outer surface of a second heat-conducting solid body or another boundary surface (e.g., a surface that serves as the outer wall of a heat pump), so that at latest when a positive pressure is applied on the side of the heat transfer fluid, the fluid-tight foil composite adapts itself to the surface structure of the open-pore solid body and thereby, e.g., a channel structure for the heat transfer fluid is formed. The fluid-tight foil composite can hereby be pre-embossed so as to fit precisely in order to adapt itself optimally to the structures in the outer surface of the heat-conducting solid body and is usually not connected to the solid body by adhesive force. While heat transfer fluid under pressure is flowing through, the inflating (and possibly bursting) of a foil composite arranged in this manner is prevented by outer stabilizing elements, in particular by the heat-conducting solid bodies or boundary surfaces arranged on both sides of the fluid-tight foil composite. In areas in which the solid body not stabilized from outside, the force distribution can also be improved, e.g., through sealing seams of the bag. If the design principle is orientated to the fact that the fluid-tight foil composite is to be understood primarily as a boundary for the heat transfer fluid structural unit, no subsequent accesses for the transport of the adsorbate to the heat-conducting, in particular open-pore, solid body need to be created. Such an arrangement furthermore has the advantage during the construction of the adsorber element of enabling very large flow cross-sections to be provided for the vapor transport of the adsorbate. Thus, e.g., on the side of a heat-conducting solid body facing away from the fluid-tight foil composite, spacers can be mounted or integrated into the solid body, e.g., in the form of a grid or a corrugated metal plate; optionally the surface of this spacer—as described above—can then be structured such that it is larger at least by a factor of 1.4 than the plane of the corresponding flat body, which plane forms the outer surface. By these means a broad vapor transport channel to the surface of the open-pore or non-open-pore heat-conducting solid body can be created. Additionally such adjacent (e.g., also arranged in mirror image) adsorber elements can be held at a distance against the positive pressure of the heat transfer fluid. In general, the preceding alternative has the advantage that no large barriers for the transport of the vaporous adsorbate are present, as is the case with the variants with adsorbate channels described further above (the barriers are formed in these from the long transport paths inside the optionally open-pore structure and/or through the bottlenecks at the passages through the covering through the vacuum-tight foil composite). In order to enable a very rapid heat transfer into the adsorber elements (and out of these), the thinnest possible plates of the heat-conducting, in particular open-pore, solid body should be used. In the variants with adsorbate channels, however, the use of thin plates means that at the same time only a small flow cross-section can be realized for the vaporous adsorbate, so that a good heat conduction is gained through high pressure losses and with low plate thicknesses, the vapor transport becomes the limiting factor for the adsorption kinetics and thus for the power density of an adsorber constructed in this way. Also with these variants with the use of a quite large number of thinner plates instead of fewer thicker plates, a larger expenditure is required for the fluid-tight (vacuum)-packing of the adsorber elements (e.g. smaller T-shaped sealing points of the fluid-tight foil composite) and a larger structural expenditure (producing the adsorbate channels; needed sealing elements). If the foil composite has a geometric shape like a cuff or a tube, the remaining facing (cut) edges (that represent the beginning or the end of this tubular structure) not yet connected to one another can also be connected together (e.g., sealed), so that a structure like a bag for fluids is formed (somewhat like a blood bag or infusion bag), in which at least one connection through which the heat transfer fluid can flow into the bag and one connection through which the heat transfer fluid can flow out of the bag, are maintained or are subsequently attached. The connections for the heat transfer fluid can be arranged as for blood bags, but they can also be situated at diagonally opposite corners (Tichelmann connection). The use of a bag-shaped foil composite with connections has the advantage that with parallel connecting of adsorber elements, the pressure loss of the heat transfer fluid that occurs as it flows through the foil composite, is particularly low. Then the individual channels for the heat transfer fluid can be designed with a smaller hydraulic diameter, so that the heat transfer on the fluid side improves. In a further advantageous embodiment, the surface of the fluid-tight foil composite and/or the outer surface of the heat-conducting solid body lying below it is structured such that a turbulent flow can form in the heat transfer fluid flowing past it. If the outer surface only of the heat-conducting solid body is structured correspondingly, the foil composite and the structure of the outer surface must be selected so that during the connection of heat-conducting solid body and foil composite, the surface of the foil composite adapts to that of the solid body. The promotion of turbulence through a rough surface is described in fluid mechanics, e.g. through the grit roughness. An adsorber element structured in this manner has the advantage that a better heat exchange with the heat transfer fluid is possible. According to the invention adsorber elements are suitable in particular in which the fluid-tight foil composite adapts to the surface roughness of the heat-conducting solid body (or has the same or only slightly different surface roughness) and thus has a surface structure that promotes a turbulent flow in the heat transfer fluid flowing past it. Since at the same time the heat transfer is to be maximized and the pressure loss in the hydraulic circuit of the heat transfer fluid is to be minimized, there is an optimization problem. The calculation methods available according to the prior art to solve this problem are to be found e.g., in the VDI-Wämeatlas (Springer-Verlag, Berlin, ISBN 3540255036, 10th edition, January 2006). The surface of the fluid-tight foil composite and/or the outer surface of the heat-conducting solid body lying below it can also be embodied such that “dimple-like” and/or groove-like and/or slit-shaped depressions are present. Groove-like depressions can for example also cross edges of the adsorber element (in particular with rectangular-shaped adsorber elements), i.e., can run over two or more areas that extend in different directions in space. These dimple-shaped or groove-shaped depressions can already be present on the surface of the heat-conducting solid body (or the solid body can be produced specifically so that these are formed), but they can also be present exclusively or additionally on the surface of the fluid-tight foil composite. An advantage of dimple-shaped depressions is the development of turbulent flows and thus an improved heat exchange with the heat transfer fluid. An advantage of groove-shaped depressions is that with these the fluid amount relative to the heat to be absorbed can be minimized. I.e., the ratio between the surface of the heat-conducting solid body and the volume of the heat transfer fluid can be increased, and the COP rises. A minimization of the fluid amount can be achieved in that the adsorber element in a heat pump or refrigerator is arranged such that the heat transfer fluid flows past the surface of the adsorber element such that it flows essentially or exclusively through the groove-shaped depressions. The hydraulic diameter of these depressions/channels should be smaller than 3 mm according to a particular embodiment. In an advantageous embodiment, the groove-shaped structure can also be based on bionic principles, such as are described e.g., in EP 1525428 B1, which leads to a uniform flow through the entire area of the fluid-tight foil composite at low pressure loss. In a further advantageous embodiment the surface of the fluid-tight foil composite and/or the outer surface of the heat-conducting solid body lying beneath it is structured such that it can be used in conjunction with a two-phase flow of the heat transfer fluid, as is known from the “heat pipes” technology (cf. for this, e.g., G. P. Peterson, “An Introduction to Heat Pipes—Modeling, Testing and Applications”, John Wiley & Sons, 1994). In particular the stated surface can be structured with fine grooves. Grooves of this type can, for example, be applied by means of a calendering method. It is possible, for example, to structure a support layer present in the foil composite (before the application of further layers) or to apply a separate structuring layer that already has the structuring or to subject the not yet structured structuring layer already contained in the foil composite (together with the foil composite) to a surface structuring method (e.g., in that the structuring is embossed by means of a structure roll). In a particular embodiment, the surface of the fluid-tight foil composite is embodied such that the grooves essentially run parallel and are arranged such that they can run essentially vertically when used in a heat exchanger or a refrigerator. The capillary effect that causes the transport of the heat transfer fluid in the fluid phase can be supported by a coating of the surface of the fluid-tight foil composite with a suitable wicking material or else can be realized exclusively by means of a wicking material. This can be any wicking material used according to the prior art for “heat pipes”, e.g., a polymer with pores in the micrometer range (as described, e.g., in U.S. Pat. No. 4,765,396), which is already applied during the production process of the foil composite, or, e.g., a thin zeolite layer on the foil composite. In a particular embodiment, the wicking material comprises a material that connects well with the fluid-tight foil composite (e.g. comprises a polymer that has similar properties to the surface of the foil composite). In all cases, it is required that the respective capillary structure be embodied such that (according to the “heat pipes” principle) an evaporation of the heat transfer fluid through heat given off by the adsorber element is possible. When adsorber elements of this type are used in a “heat pipe”, the heat transfer fluid then does not flow around the adsorber elements; rather, in the fluid phase it is “drawn along” the adsorber element through the capillary action of the groove-shaped depressions or the wicking material and is evaporated by heat input. For the vapor transport suitable channel structures according to the invention must then be provided, as are known from the prior art for heat pipes. For example, vapor channels can be provided for this, which vapor channels are formed by two adsorber elements arranged adjacent to one another. The embodiment described above, that the fluid-tight element has a surface condition with which a suitability for a use in a “heat pipe” can be realized, represents an own invention (independent of a combination of the feature of the “surface condition of the fluid-tight element” with the feature that an open-pore solid body must be contained). Advantageous embodiments of this invention are given from the features of the subordinate claims (without the respective dependencies being valid hereby). In an advantageous embodiment the adsorber element according to the invention has a geometric shape like a rectangle, a spiral, or a hollow cylinder. Adsorber elements with a geometric shape like a rectangle have a substantially smaller extension in one direction than in the two other directions in space according to a particular embodiment; this also holds true for shapes derived from such a rectangle, such as a spiral or hollow cylinder. According to the invention hereby a geometric shape like a rectangle in addition to pure rectangles is also understood to mean any geometric shape that results in a rectangle through the effect of force in a direction of space, without considerable changes in the size of the surfaces of the rectangle taking place (in particular stackable geometric bodies are to be named, furthermore groove-shaped or bowl-shaped deformed rectangles or else rectangles with convex and/or concave outer surfaces or partial surfaces also fall under this). The geometric shape of these adsorber elements like a rectangle therefore, in a particular embodiment, approaches the shape of a thin plate (this holds true—as mentioned—also for the hollow cylinder that is derived from a plate whose ends were “twisted” with respect to one another respectively by 180° and holds true likewise for a spiral-shaped adsorber element that is derived from a “rolled-up” plate). Decisive for the shape of the adsorber element is that forming heat has a shortest possible path to the outer surface of the adsorber element, where it is dissipated to the heat transfer fluid via the fluid-tight foil composite. If the adsorber element is a hollow cylinder, the feed of the adsorbate can also take place in the interior of the hollow cylinder. In a particular embodiment, the adsorber element with a geometric shape like a rectangle has a geometry in which the three respectively facing pairs of surfaces of the rectangle fulfill the following conditions: The first facing pair of surfaces, in a particular embodiment, has an average spacing of 1 mm to 30 mm, or, in a more particular embodiment, 0.4 to 20 mm, or, in an even more particular embodiment, 1 to 8 mm. The second and the third facing pairs of surfaces of the rectangle have an average spacing that is greater at least by a factor of 4 and, in a particular embodiment, at least by a factor of 10, than that of the first pair of surfaces. In a particular embodiment, the surface of the two largest lateral surfaces of the geometric shape like a rectangle is respectively larger than the rectangle of the average spacing of these surfaces at least by a factor of 16, or, in a more particular embodiment, at least by a factor of 50, and, in an even more particular embodiment, at least by a factor of 100. An adsorber element embodied in this manner has the advantage that the path that the heat must travel from the sorption material to the outside of the adsorber element (i.e., to the outside of the fluid-tight foil composite), can be minimized. In an advantageous embodiment the adsorber element according to the invention with a geometric shape like a rectangle, a spiral, or a hollow cylinder has groove-shaped and/or dimple-shaped and/or slit-shaped depressions in the heat-conducting solid body to which the fluid-tight foil composite clings. By these means the thermal path can be further reduced. A possibility of the particularly good utilization of the total volume with a very short thermal path is to arrange these groove-shaped and/or dimple-shaped and/or slit-shaped depressions such that the projections lying between two depressions can engage in the depressions of an adjacent adsorber element with the same type of surface structure, so that the two adjacent adsorber elements engage in one another like two combs and between the adsorber elements a rolled, also narrow in a particular embodiment, split remains free for the heat transfer fluid. A surface structure of this type, which can be for example corrugated or comb-like, can be present on one or more surfaces on one or both surfaces of the pair of surfaces with the smallest average spacing according to a particular embodiment. The heat-conducting, in particular open-pore solid body used in the adsorber elements according to the invention, is composed of a metal and/or a ceramic or contains a metal and/or a ceramic according to exemplary embodiments of the invention. According to the invention, therefore, the heat-conducting solid body can also be understood to mean a solid body based on a metal (or an alloy), which for specific applications contains admixtures, such as, e.g., ceramic particles; likewise it can be understood to mean a ceramic heat-conducting solid body that for specific applications contains ceramic or non-ceramic admixtures (e.g., metallic particles to increase the thermal conductivity). In general, the solid body should have the highest possible thermal conductivity. If the heat-conducting solid body is a non-open-pore solid body, it should have a thermal conductivity greater than 30 W m −1 K −1 , according to a particular embodiment or, according to another particular embodiment, greater than 150 W m −1 K −1 . If the heat-conducting solid body is an open-pore solid body, however, it should at the same time have the highest possible porosity. The skeleton material of the open-pore solid body, in a particular embodiment, should have a thermal conductivity greater than 30 W m −1 K −1 or, in a particular embodiment, greater than 150 W m −1 K −1 . The open-pore solid body as such should, in a particular embodiment, (in particular in the direction perpendicular to the contact surface with the foil composite) have a thermal conductivity greater than 6 W m −1 K −1 . With an anisotropic structure of the open-pore solid body, the thermal conductivity should be highest along the shortest path to the heat transfer fluid. If a heat-conducting solid body of ceramic or based on a ceramic is used, e.g., aluminum nitride and/or silicon carbide can be used for this. In a particular embodiment, the heat-conducting solid body comprises metal or contains a metal. In particular examples according to the invention, the metal is selected hereby from aluminum, copper, silver, and alloys of these elements, since these have a particularly high thermal conductivity. In a variant, reinforced metal matrices, in particular copper matrices, are used as metal-containing open-pore solid bodies with carbon fibers, such as short carbon fibers, which matrices excel through adaptable temperature expansion behavior and high thermal conductivity. In particular embodiments, such composite materials have 30-65% by volume carbon fibers, wherein depending on the consolidation method, various orientation distributions of the fibers can be established in the metal matrix. If a metallic body, in particular a porous metallic body is used as a heat-conducting solid body, it can be produced in particular by powder metallurgy methods, sintering methods, screen-printing methods, and/or casting methods. A powder-metallurgical production of an open-pore metallic body can take place, e.g., in that porous structure elements comprising an organic material (which have the structure of the later embodied pores) are acted upon by a metal powder or metal powder mixture, and subsequently are subjected to a thermal treatment, wherein (usually in a first stage) the organic material is expelled. Usually the production of the porous metallic body then takes place in a second stage by sintering. Alternatively a deposition of metals on the surface of the organic material can also take place (for example, a deposition from the gas phase, e.g., with nickel). The porous structure element comprising organic material can for example also be a body comprising (optionally under pressure) spherical structures (for example polystyrene balls) sintered together. The powder metallurgy route can also be used for the production of open-pore ceramic materials; hereby the organic base body must then be coated with ceramic powder particles and then be sintered, wherein the organic component is expelled. An open-pore metallic structure can be obtained by means of a screen-print method, in that a layer-wise build-up of the structure takes place through screen printing. The structuring is undertaken hereby through mask variation. Usually a subsequent debinding- and/or sintering step is necessary after the layer-wise generation of the structure. An open-pore structure can be produced with this method that is independent of the structure of an organic (structure-forming) base material; it can also be used for the production of ceramic open-pore solid bodies. In a particular variant, the heat-conducting, in particular open-pore, solid body is produced at least partially by means of a casting method. Hereby in particular a casting method is advantageous in which an organic material reproducing the pore shape is introduced into a casting mold, which is subsequently infiltrated with a metal melt or a metal-containing melt. For example, an aluminum pressure die casting method is cited in which an aluminum melt is pressed very quickly into a cooled mold that contains granules of a polymer material that displaces the melt and thus leads to the porous structure of the cast component. After the metal melt or metal-containing melt has solidified at a temperature below the melt temperature of the metal (or the liquid temperature), the organic material (or the polymer granules) is melted out. In a particular embodiment, the casting method is carried out such that an infiltration of the polymer granules takes place without their melting-out. For example, polystyrene is cited as a possible material for the polymer granules. As the metal melt, in a particular embodiment, a melt with a melting point that is lower or the same as that of aluminum, is used; melts of aluminum (e.g., technically pure, i.e., 99.7% aluminum) or aluminum alloys are used in a particular embodiment. The casting method, according to a particular embodiment, is a pressure die casting method; however, a precision casting method, for example, is also conceivable according to the invention. The use of a casting method with melt infiltration has the advantage that by means of the organic material contained therein, it can be determined exactly which surface condition and which pore structure the open-pore solid body possesses. Furthermore, gradients can be established in the pore structure, channels that run through the open-pore solid body can be recessed, and solid structure elements that serve the mechanical stability of the open-pore solid body or of the adsorber element can be provided. A particular method of the production of the open-pore solid body by means of a pressure die casting method, according to the invention, comprises inserting the polymer body to be infiltrated into one of the halves of the casting cavity in the metallic casting die of the pressure die casting equipment and subsequently infiltrating with modified parameters of the pressure die casting process. Elevations and fixing elements for any vapor transport channels as well as elevations for groove-shaped or dimple-shaped depressions or other structurings of the solid body surface are contained in the casting mold according to a particular embodiment of the invention. It is also conceivable thereby to produce the open-pore solid body or the adsorber element from several parts respectively produced by means of a pressure die casting method. However, the pressure die casting method is carried out, according to a particular embodiment, such that the open-pore solid body (optionally with structure elements contained therein) is produced in one piece. An open-pore metal-containing solid body can also be obtained through a sintering of metallic or metal-containing fibers. As metal fibers, in principle fibers of all metals are suitable. Fibers with the highest possible thermal conductivity should therefore be selected. Fibers of an AlCuZn alloy are cited by way of example. Here too channels can be provided in that appropriately shaped organic materials that can later be melted out, are contained as place-holders during the structure-forming sintering process. An alternative way of introducing channels is to sprinkle fibers on a mold whose surface already contains a negative of the desired structures, and then to sinter this pre-shaped fiber mat. Here too solid structure elements can be obtained by introducing appropriate solid components (in particular metal parts). When short fibers in the length range of 3 to 25 millimeters are used, an anisotropy of the open-pore solid body structure can be established that leads to reduced flow losses and can thus be advantageous for the loading of the element (in particular the flow losses in the longitudinal direction with rectangular-shaped adsorber elements are reduced). In an advantageous embodiment, the heat-conducting open-pore solid body contained in the adsorber element according to the invention has the highest possible specific surface area. This ensures that the heat transfer from the sorption material via the open-pore solid body to the fluid-tight foil composite and its heat transfer fluid can take place particularly efficiently. The specific surface area of the open-pore solid body is therefore greater than 2,500 m 2 /m 3 in a particular embodiment, such as greater than 10,000 m 2 /m 3 , and, according to a further embodiment, greater than 25,000 m 2 /m 3 . The specific surface area is hereby determined by means of X-ray computer tomography and subsequent image analysis. If the heat-conducting solid body has an outer surface coated with sorption material, which surface is structured such that this structured outer surface is greater at least by a factor of 1.4 than the plane forming the outer surface of the corresponding flat body, the portion of the specific surface area pertaining to this structured surface also has a value increased by this factor compared to the flat body. According to a particular embodiment of the invention, whereby the heat-conducting solid body is open-pore, the solid body is traversed by one or more transport channels for the adsorbate; these channels should have at least a diameter such that an orientated flow still prevails therein even with the lowest use-relevant vapor pressure, i.e. no Knudsen diffusion. In a particular embodiment, in particular when the design principle of the adsorber elements is orientated towards the fluid-tight foil composite being understood primarily as a boundary for the adsorbate/sorption material/heat-conducting solid body structural unit, the transport channels branch in a fractal structure, as is known from the solution of flow problems in nature (e.g. in leaves of plants, see, e.g., Strasburger Lehrbuch der Botanik, ISBN 3827413885, Spektrum Akademischer Verlag, 2002). The fractal channel structure for the transport can, e.g., be embossed into the casting mold during a production of the open-pore solid body by means of a casting method. The adsorption heat pump or adsorption refrigerator according to the invention contains at least one adsorber element that includes a heat-conducting solid body and a sorption material arranged on the surface of this solid body for a vaporous adsorbate, wherein a fluid-tight foil composite is arranged on the outer surface of the heat-conducting solid body, at least in the areas in which a contact with a heat transfer fluid is provided. The at least one adsorber element is embodied thereby such that the heat exchange between the heat-conducting solid body and the heat transfer fluid can take place via the fluid-tight foil composite. Usually the adsorption heat pump or adsorption refrigerator according to the invention furthermore contains an evaporator, a condenser (wherein also a component is possible that functions both as an evaporator and as a condenser). If the design principle of the individual adsorber elements or of the heat pump or refrigerator is orientated towards the fluid-tight foil composite being understood primarily as a boundary for the adsorbate/sorption material/heat-conducting solid body structural unit, the heat pump or the refrigerator usually also have a vacuum-tight (but at least fluid-tight) adsorbate channel that is connected via connections to the adsorber element, the evaporator and the condenser. The adsorber elements packaged in a fluid-tight manner are then usually arranged in a container such that the heat transfer fluid flows around them in as full-surface a manner as possible, and the container limits the space that the heat transfer fluid occupies. On the other hand, if the design principle is orientated towards the fluid-tight foil composite being understood primarily as a boundary for the heat transfer fluid structural unit, an adsorbate channel is not absolutely necessary. The adsorbate channel can be omitted in particular when the at least one adsorber element, the condenser and the evaporator are arranged in the same shell (or the same housing), since the vapor of the adsorbate can flow towards the adsorber element from all sides. The adsorber elements are then usually arranged in a container such that the vaporous adsorbate can come into contact as simply as possible with the sorption material arranged on the surface of the heat-conducting solid body and the container limits the space that the vaporous adsorbate occupies. During the operation of the heat pump or refrigerator, the heat transfer fluid (e.g., water, a water/glycol mixture or in the case of a two-phase flow, e.g., also methanol) flows round the adsorber elements or the fluid-tight foil composite applied onto their outer surface, and thus they are heated during the desorption phase and cooled during the adsorption phase. A particular use of the adsorber elements according to the invention is the use in an adsorption refrigerator or adsorption heat pump, in which a traveling temperature gradient (“thermal wave”) is generated in the heat transfer fluid. For this an arrangement with at least two adsorber units that respectively contain at least partially the adsorber elements according to the invention, is required. With these “thermal wave” methods a major part of the sensible heat stored in the thermal mass of the adsorber units or adsorber elements can be exchanged between the two adsorber units. At the end of this “thermal wave” process the two adsorbers do not have the same average temperature; rather, the originally hot adsorber (that was previously desorbed) has a distinctly lower temperature than the originally cold adsorber (which has previously adsorbed). The “thermal wave” method is disclosed, e.g., in U.S. Pat. Nos. 4,610,148 and 4,694,659. A great variety of proposals have been made in the past for realizing the “thermal wave” process. Up to now, however, no arrangement of the adsorber elements has been proposed that realizes this “thermal wave” principle and that enables a simple adsorber construction that is not prone to malfunction and is cost-effective. With a heat pump or refrigerator in which the adsorber elements according to the invention are connected in series, this is now possible for the first time; therefore for the first time an efficient heat recovery according to the “thermal wave” principle is realizable. In an advantageous embodiment for the variant in which the fluid-tight foil composite is to be understood primarily as a boundary for the adsorbate/sorption material/heat-conducting solid body structural unit, two adjacent adsorber elements respectively of the heat pump or refrigerator according to the invention are connected by means of at least one adsorbate channel, wherein at least one adsorbate channel to which two adjacent adsorber elements are connected, is arranged on an axis on which further adsorbate channels of further adsorber element pairs are situated. In a particular embodiment of the invention, all or at least most of the adsorbate channels are situated on those axes that run through the entire adsorber element stack. An arrangement of this type has the advantage that only a compression of the stack of adsorber elements and adsorbate channels along the axis of the adsorbate channels is necessary for the vacuum-tight connection of the adsorbate channels to the adsorber elements. Sealing elements that seal along the adsorbate channel axis when pressure is exerted, can additionally be provided hereby. Furthermore, in adsorber element/adsorbate channel stacks of this kind (with or without sealing elements), the adsorber elements are embodied, in a particular embodiment, such that at the points at which (through the compression of the stack) the contact pressure arises, are mechanically so stable that they withstand this contact pressure. In order to achieve the vacuum-tight connection of the adsorbate channels to the adsorber elements in the adsorbate channel/adsorber element stack described above or to generate the contact pressure necessary for this, a holding element can be provided in the heat pump or refrigerator according to the invention that runs inside the adsorber elements through the adsorbate channels arranged on an axis. Alternatively, the holding element can also run completely outside the adsorber elements. At the ends of this holding element, means must be provided with which the necessary contact pressure can be generated, so that the vacuum-tight connection of adsorbate channels and adsorber elements can be realized. In a further advantageous embodiment, two or more adsorbate channels (three, in a particular embodiment) that do not lie on a straight line are situated between two adjacent adsorber elements. If each adsorber element of an adsorber element/adsorbate channel stack is connected to at least three vapor channels (or if both sides of an adsorber element are counted, six vapor channels), which vapor channels do not lie on a straight line running crossways to the stack, the danger of leakages of the adsorber element/adsorbate channel stack due to the canting of individual adsorber elements is greatly reduced. In a further embodiment, the heat pumps or refrigerators according to the invention contain at least partially adsorber elements that have a geometric shape of a rectangular type. In a particular embodiment, the average spacing between two adjacent adsorber elements of this type is less than the average spacing between the first surface pair facing one another of the geometric body of a rectangular type (which again is less than the spacing between the second and third surface pairs facing one another of the geometric body of a rectangular type). In a particular embodiment, the average spacing is less than 20 mm. This spacing can be established, e.g., by means of spacers (for example, also in the form of adsorbate channels and/or sealing elements); however, these are not absolutely necessary if the foil composite has a geometric shape like a cuff or a tube. The smaller the spacing between adjacent adsorber elements, the higher the tendency to develop a turbulent flow in the heat transfer fluid and the better the heat transfer from the adsorber element to the heat transfer fluid. However, the pressure loss in the hydraulic circuit of the heat transfer fluid is also higher thereby. Usually an average gap width of 0.5 mm to 5 mm is therefore wise. With special embodiments this can also be larger (up to 30 mm). If a foil composite with a geometric shape like a cuff or a tube is used, the extent to which the foil bag can inflate is determined by an outer enclosure of the adsorber element or a stack of them. In a particular embodiment of this variant, the adsorber elements are pressed together by an outer stable frame such that the foil bag or the foil tube are clamped between each two adsorber elements and channels for the heat transfer fluid can develop only in the area of the recesses in the solid body of the adsorber elements in the bag/tube. Although the pressure loss here will generally be greater than in the case of a full-surface flow-around, the flow distribution can be controlled considerably more precisely and the total amount of heat transfer fluid in the adsorber circuit can be reduced. In the heat pumps or refrigerators according to the invention, several adsorber elements are contained according to a particular embodiment, such as exclusively adsorber elements, that are approached or can be approached by the flow of the heat transfer fluid in series and/or parallel. In a particular embodiment, the adsorber elements then have a geometry like a rectangle, such as plate-shaped. In an advantageous variant the adsorber elements in the heat pump or refrigerator according to the invention are arranged in the shape of an adsorber element stack like a comb. The adsorbate channel (through which the vaporous adsorbate is led to the adsorber elements) can run in the “back” of the comb thereby. This is wise in particular when the heat transfer fluid does not flow through a foil composite a geometric shape like a cuff or a tube. A serial approach flow to the adsorber elements by the heat transfer fluid can be realized here particularly simply. Two adsorber element stacks like a comb are positioned with respect to one another hereby such that the “tips” of the combs engage in each other and the heat transfer fluid can therefore flow through this arrangement in the shape of a meander. Additionally, the adsorber element stacks—also with parallel flow-round—can contain at least partially (or, in a particular embodiment, exclusively) respectively adjacent adsorber elements with groove-shaped and/or dimple-shaped and/or slit-shaped depressions that are arranged such that the projections of the one adsorber element lying between two depressions can engage in the depressions of the adjacent adsorber element with the same type of surface structure, so that also these adjacent adsorber elements can engage in one another like two combs. If a foil composite with a geometric shape like a cuff or a tube is used in an arrangement in which two adsorber element stacks like a comb are positioned such that the heat transfer fluid can flow through the arrangement in the shape of a meander, this tube can be arranged between the adsorber element stacks like an accordion folding. The same arrangement is also possible when the adsorber elements are only arranged one on top of the other like a paper stack. In both cases (e.g., tubular) adsorbate channels running along the bend or deflection point can be arranged along the sides of the adsorber element at which the accordion folding has a bend or deflection point. By these means it is on the one hand possible to protect the heat transfer fluid tube from damage at the bends or deflection points (for instance during installation), and on the other hand a yet better distribution of the adsorbate is possible, in particular with open-pore solid bodies. A similarly advantageous arrangement can be realized with adsorber elements with a spiral geometry (i.e., that the adsorber element is derived from a “rolled-up” plate), in that a heat transfer fluid tube that is then likewise spiral in shape, is arranged between the branches of the spiral. Also independent of the use of a foil composite with a geometric shape like a cuff or a tube, special fluid routings are possible through the spiral shape, which routings lead to a low total pressure loss when the heat transfer fluid flows through the adsorber element and that will be described below: advantageously at the spiral-shaped rolled-in edges of the adsorber element, heat transfer fluid collecting channels are situated that have a considerably larger flow cross-section than the channels for the heat transfer fluid that run essentially perpendicularly thereto and are embossed into the surface of the solid body. In order to achieve a winding space that is less than the diameter of the collecting channels, a diagonal winding of the adsorber element and/or a geometric shape of the adsorber element with non-parallel running edges can be selected. In a further advantageous embodiment, such an adsorber element has the basic shape of a trapezoid and is rolled up starting from the wider side towards the narrower side, resulting in a cylinder that thickens in the center. In order to achieve a uniform flow-through of the entire surface of the plate, the flow cross section of the channels embossed into the surface of the solid body is to be selected smaller in the vicinity of the narrower edge than in the vicinity of the longer edge, so that the pressure loss of these channels is approximately the same at the same volume flow. In a particular embodiment, both in the serial and the parallel flow-round of the adsorber elements, the trough surrounding the adsorber element stack should have the lowest possible heat capacity, i.e. for a given material should have the lowest possible weight. In general the heat pumps or refrigerators according to the invention are designed, according to a particular embodiment, so as to maximize the mass fraction of the adsorbent compared to the fraction of the inert mass that must be thermally cycled using sensible heat. In addition to the above-described comb-shaped arrangement of adsorber element stacks, the heat pumps and refrigerators according to the invention can of course also contain in addition groups of adsorber elements arranged in other ways; moreover it can also have several adsorber units connected together (i.e. units of respectively two or more adsorber element stacks or groups of adsorber elements arranged in other ways) according to the principles described above. In principle all variants for the connecting of several adsorber element units that are known from the prior art are possible (cf., e.g., M. A. Lambert et al. “A Review of Solid-Vapor Adsorption Heat Pumps”, 41 st AIAA Aerospace Sciences Meeting and Exhibit, 2003, Reno, Nevada, 2003-0514). The present invention—without limiting its generality—is explained below in more detail based on drawings. They show: FIG. 1 : Section of a profiled adsorber element; FIG. 2 : Section of an adsorber element in which the foil composite is present like a tube or a cuff or a bag; FIG. 3 : Combination of an adsorber element based on a heat-conducting open-pore solid body with an adsorber element based on a massive heat-conducting solid body; FIG. 4 : Section through an adsorber element in which a heat-conducting open-pore solid body are combined with a massive heat-conducting solid body; FIG. 5 : The construction of an adsorber unit for realizing a “thermal wave” in top view; FIG. 6 : A further construction for realizing a “thermal wave”; FIGS. 7 a , 7 b : The application of a foil composite to an e.g. open-pore solid body and an adsorbate channel and the course of the welded seams with an adsorber element stack formed herefrom, in which the individual adsorber elements are arranged like a comb; FIGS. 8 a , 8 b : One or two adsorber elements with a surface structure of groove-shaped depressions engaging in one another. DETAILED DESCRIPTION OF THE INVENTION In FIG. 1 a section of an adsorber element is shown in which an open-pore solid body 1 is packaged (e.g., welded) with a composite film 2 ,(foil composite, hereafter), e.g., by means of a vacuum packing process. For the connection of adsorbate channels 24 , a profiling 12 in the form of a circular notch or groove is provided in this adsorber element. A sealing element 11 in the form of a ring can be laid in this groove, so that a vacuum-tight connection with the adsorbate channel 24 can be produced when a contact pressure is applied. In the center of the profiling 12 a hole 13 is bored into the open-pore solid body 1 , in order to enable a better distribution of the vaporous adsorbate in the adsorber element or in the open-pore solid body, which is coated with the sorption material. Furthermore, a fastening element can be led through the hole 13 , by means of which the contact pressure can be applied to achieve a vacuum-tight connection between adsorber elements and adsorbate channels. FIG. 2 shows a section of an adsorber element in which a foil composite 2 with a geometric shape like a tube or a cuff (which however can only be seen in the form of two layers of the foil composite) is arranged between two layers of an open-pore solid body 1 . The remaining not yet joined together (cut) edges of the foil composite 2 here project from the solid body 1 and, except in the area of the connections 19 for the heat transfer fluid, are likewise sealed together so that the foil composite has the shape of a bag. The heat transfer fluid can flow into or out of the bag via the connections 19 . FIG. 3 shows a combination of an adsorber element based on a heat-conducting open-pore solid body with an adsorber element based on a massive heat-conducting solid body. In an open-pore heat-conducting solid body 1 a , groove-like depressions are provided on the side facing the fluid-tight foil composite 2 a . The foil composite 2 a is applied onto the open-pore heat-conducting solid body 1 a in such a way that it adapts itself to the surface structure or is alternatively structured such that the surface structure corresponds to that of the open-pore solid body 1 a . Furthermore, a massive solid body 1 b is structured on its side facing away from the fluid-tight foil composite 2 b such that a sawtooth profile is formed. A coating with a sorption material is arranged on this side. Sorption material is likewise arranged on the inner and outer surface of the open-pore solid body 1 a . Alternatively, as a massive solid body 1 b , a metal plate can also be used that is “folded” so that a sawtooth profile is formed. The foil composite 2 b is then applied on the side of the massive solid body lb facing the fluid-tight foil composite 2 b . Between the layers 2 a and 2 b of the foil composite (which can also be connected together respectively on the (cut) edges lying on top of one another on the two longer sides facing one another, so that a foil composite with a geometric shape like a cuff or a tube is present), a channel 22 for the heat transfer fluid exists, wherein the latter flows essentially through the groove-like depressions. FIG. 4 shows a cut through an adsorber element, in which a heat-conducting open-pore solid body is combined with a massive heat-conducting solid body. Here the cut gives a type of rectangular profile. A massive heat-conducting solid body 1 b , with a thickness d (such as, e.g., a thickness 15 μm to 250 μm), is coated with a thin layer of fibers of the same basic material, is sintered or soldered (the layer thickness e of the fibers, in a particular embodiment, is in the range of d<e<10*d) according to a particular embodiment, so that an open-pore solid body 1 a is arranged on the solid body 1 b . The corrugated-metal-type structure of the solid body 1 a / 1 b is obtained in that a flat solid body metal plate is folded such that bridges of the width a towards the foil composite result. The height h of the folded structure is clearly greater than a, in the range of 3*a<b<30*a, according to a particular embodiment. The optimum side ratio also depends on the thickness of the fiber layer in relation to the metal plate thickness (e:d). On the uncoated bridges a foil composite 2 (here shown three-layered; not true to scale) is arranged, which as a rule is connected with adhesive force to the massive solid body 1 b. The thermal conductivity in direction f can be considerably higher than with a homogeneous open-pore solid body (e.g., the fiber structure or 1 a in FIG. 2 ) and depends essentially on the ratio of the metal plate thickness d to the folding distance a ab. The ratio of the thermal conductivity (in the preferred direction) of the solid body obtained in this way to a massive solid body comprising the bulk material of the massive solid body 1 b is at least 2 d/a . The fiber layer or the open-pore solid body 1 a additionally improves the heat conduction. The fiber layer 1 a contributes decisively to the mechanical stabilization of the solid body (in particular bending stiffness), since the solid body must accept the pressure difference between the heat transfer fluid flowing inside a bag formed from the foil composite 2 and the adsorbate vapor pressure on the other side of the foil. This pressure difference is typically between 1.5 bar and 4 bar for low-pressure adsorbates (water, methanol). The pressure stability of the solid body obtained in this way with load in direction f can likewise be considerably higher than with a homogeneous porous solid body of the same porosity or effective denseness. This enables a high porosity and specific surface area of the solid body, through which more sorption material can be introduced and the heat ratio increases in a sorbate/sensible manner in favor of a higher COP. The cavities create obstacle-free flow channels 24 a , 24 b for the vapor of the adsorbate and thus prevent the adsorption kinetics from being limited through the vapor diffusion. In addition, they make it possible to produce relatively wide adsorber elements without vapor transport limitation. Through the large-area contact of the foil composite with the bridges not coated with fibers, the heat transfer from the solid body 1 b to foil is greatly improved and is in particular considerably better than with a homogeneous porous solid body 1 a (see FIG. 2 ). FIG. 5 shows a construction of an adsorber unit for the realization of a “thermal wave” in top view. The adsorber elements 21 are combined to produce two adsorber element stacks that together with the boundary 31 respectively form an adsorber element stack like a comb. The respectively adjacent adsorber elements 21 from the two adsorber element stacks have a small spacing from one another, so that the adsorbate channels 24 arranged on an axis between the adsorber elements are only very short (and essentially are formed by the sealing element 11 ). The two comb-like adsorber element stacks are inserted into a trough 25 (whose side walls form the rear boundary 31 of the comb-like adsorber element stack), through which the heat transfer fluid flows. Through the alternating arrangement of the adsorber element stack, which gives the heat transfer fluid room to flow past respectively only at one side of the trough, the fluid must flow through a meander-shaped channel 22 between all the adsorber elements successively. Through this a temperature gradient can be established along the heat transfer fluid channel axis and thus a “thermal wave” can be realized. A holding element 15 (e.g., a threaded rod) runs through the entire arrangement of adsorber elements 21 and adsorbate channels 24 ; a hole 13 is provided in each open-pore solid body 1 , which hole is situated in the center of the profiling 12 for a sealing element 11 . Through the adsorbate channels 24 and the holes 13 provided in the open-pore solid bodies 1 , adsorbate can flow into the open-pore solid bodies 1 . In FIG. 6 the adsorber elements 21 are likewise arranged to form an adsorber element stack like a comb. Here the adsorbate channel 24 runs in the “back” of the comb. The combs are pushed into one another such that a meandering channel results for the heat transfer fluid 22 . For this, the individual adsorber elements are applied on the adsorbate channel parallel to one another with the narrow sides, which adsorbate channel can be composed, e.g., of a suitably perforated aluminum double-bridge plate. The spaces between the plates are selected so large that a second “comb” of the same construction can be pushed into the first in mirror image. The combs can be packed in either in a fluid-tight foil composite (which is not shown here) (cf. FIGS. 7 a and 7 b ), or a tube-shaped foil composite (which is not shown here) can be inserted into the channel 22 , so that the foil composite is arranged in accordion folds. The channel for the heat transfer fluid 22 then runs between the two combs that have been pushed into one another. If the two combs are pushed into one another so far that they touch each other, only parallel slits remain between the adsorber elements. In this case, a parallel approach flow of the adsorber elements is then realized. If a tube-shaped foil composite is used, the tube must respectively also have a connection for inflow and outflow of the heat transfer fluid between each two adsorber elements. In any case, the two combs are arranged in a suitable trough for the heat transfer fluid and fixed in their position. The channels for the vaporous adsorbate are connected in a suitable manner (corresponding to the prior art for adsorption heat pumps) to evaporators or condensers of the heat pump via suitable valves. To this end, a vacuum-tight connection between the fluid-tight foil and another massive component (e.g. an aluminum profile part) must be produced for each individual comb structure of adsorber elements only at one or two places (i.e., the “ends” of the comb). A serial or parallel construction of this type is very easy and cost-effective to convert in series production for heat pumps and refrigerators. FIG. 7 a shows the application of a foil composite onto heat-conducting, in particular open-pore, solid bodies and an adsorbate channel. Here, a comb-like adsorber element stack (as shown, e.g., in FIG. 5 ) is driven into a web of the foil composite 2 that is so much wider than the comb structure that enough room remains on both sides of the comb to weld the projecting foil composite. FIG. 7 b shows the course of the welded seams 3 of the foil composite 2 in a comb-like adsorber element stack. The adsorber elements (i.e. the heat-conducting solid body 1 and the adsorbate channel 24 ) are fully enclosed by the fluid-tight foil composite 2 after the welding. At the points at which an adsorber element meets the collecting channel, two welded seams then meet each other in the shape of a T, i.e., a T-shaped vacuum-tight connection results. FIG. 8 a and FIG. 8 b show one or two adsorber elements 21 with which a particularly good utilization of the total volume is achieved with a very short thermal path. Groove-shaped depressions 31 are arranged in the adsorber elements 21 hereby such that the projections 32 lying between two depressions can engage in the depressions 31 of an adjacent adsorber element 21 with the same type of surface structure, so that the two adjacent adsorber elements engage in one another like two combs and a winding. Also, according to a particular embodiment, a narrow channel remains free for the heat transfer fluid 22 . If a tube-shaped foil composite is used, the tube must also have between each two adsorber elements, another connection respectively for inflow and outflow of the heat transfer fluid.

The invention relates to an adsorber element for a heat exchanger and an adsorption heat pump or adsorption refrigerator that contains at least one such adsorber element. The adsorber element includes a heat-conducting solid body and a sorption material for a vaporous adsorbate arranged on the surface of this solid body. A fluid-tight foil composite is arranged on the outer surface of the open-pore solid body, at least in the areas in which a contact with a heat transfer fluid is provided, wherein this adsorber element is embodied such that the heat exchange between the open-pore solid body and the heat transfer fluid can take place via the fluid-tight foil composite.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to apparatus for telemetering singals in an electronic circuit over long distances and more particularly to digital data-telemetry links utilizing an encoder at the data transmitting end of a system, a decoder at the receiving end, and a cable transmission link connected therebetween. 2. Description of the Prior Art Every since man began to extract oil, gas and other minerals from beneath the surface of the earth on a commercial basis, there has been a need for determining the environmental characteristics existing at various depths in a borehole. In the earliest days of petroleum and mineral exploration, such boreholes were not excessively deep, and the required information concerning the environment was not particularly complex. As a result, the logging instruments used to acquire such information were basically simple and did not have to operate in particularly hostile surroundings. However, as shallow petroleum and mineral deposits were exploited, boreholes became ever deeper and more expensive, requiring not only an increase in the sophistication of drilling techniques but also improved knowledge with increasing detail and reliability about the rock formations through which the borehole passed. Furthermore, the increased scarcity and value of petroleum and mineral products often led to secondary-recovery projects, further adding to the requirement for more detailed knowledge of the rock formations and the fluids contained in them. This added information often had to be obtained in an increasingly hostile environment characterized by high temperatures and pressures and by long cables for data transmission and control of the subsurface equipment. As logging cables became longer and correspondingly hotter, their losses at both high and low frequencies became more severe. As a result, signals transmitted over long cables were attenuated and otherwise distorted, causing amplitude measurements at the surface to have reduced accuracy owing to large unstable attenuation ratios and contamination by noise. This problem was particularly severe whenever the amplitude of relatively narrow pulses was important, because the high-frequency attenuation and distortion of long cables tended to be considerably larger than those at low frequencies. These attenuation and distortion effects were also objectionable for shorter cables whenever newer sophisticated subsurface instruments required more precise amplitude analysis than that required by older instruments. Limited cable bandwidth also caused problems even when standard-amplitude pulses were used and only their average rate of arrival was important. In that case the limited cable bandwidth forced the transmission of pulses with widths considerably longer than that required by detectors and signal-processing electronics alone, thus often providing the limiting factor with regard to pulse rates and dynamic range in frequency. Furthermore, the direct transmission of pulses with random spacings caused problems involving the accidental occurrence of two pulses nearly simultaneously within the restricted response time of the cable, limiting the permissible average pulse rates even beyond that limit required for signals with fixed minimum pulse spacings. This pulse-pileup problem became more severe whenever pulse-amplitude information was desired, adding to the errors from attenuation, distortion and noise. One solution to this problem known in the prior art involved preventing a second pulse from being sent up the cable until a first pulse had sufficient time to decay to a negligible level. Although this fixed-dead-time technique avoided amplitude and count-rate distortions from pulse pileup, it limited the rate at which information could be transmitted to the surface and sometimes resulted in unacceptable statistical variations. The presence of such fluctuations, in turn, limited the speed with which the formations could be logged, and in extreme cases they have actually forced the logging tool to remain stationary at discrete points instead of moving constantly to provide a continuous record. For the case where only average pulse repetition rates were important, several other partial solutions to the pulse-pileup problem existed in the prior art. Sometimes a digital counter reduced the raw counting rates to a level consistent with the cable bandwidth. Although this technique did not directly increase the statistical variations for random signals, it did add errors at low counting rates where the lost data contained in the state of the prescaler were significant. Making the length of the prescaler controllable from the surface alleviated this difficulty by adapting the prescaler to the measured counting rate, but the required two-way communications link and its associated complexity were seldom justified. Alternatively, de-randomizing scalers which provided an output frequency which was a short-term average of the input frequency avoided much of the pile-up problem caused by random pulse spacings, but still the upper operating frequency remained severely limited by the restrictive cable bandwidth. A second class of problems arose because of the need to transmit information from several data sources. For example, in a logging tool for correlating formation parameters with pipe position as defined by counting pipe (casing) collars, a neutron source together with gamma-ray and neutron detectors has often been used in the prior art. Including the need to detect the casing collars, such a tool already has three data sources. Monitoring other parameters indicative of proper tool operation, such as temperature, or indicative of further formation properties, such as natural gamma radiation, further increased the need for handling multiple data sources. This problem became even more severe for more sophisticated tools such as those employing neutron generators capable of being rapidly pulsed on and off. Even though the interaction of neutrons with the material surrounding the tool was very complex, the limited capacity of prior-art data-transmission systems forced the specialization of such tools, allowing them to observe and record only a small fraction of the parameters characterizing the neutron interaction. As a result, the prior art contained neutron-lifetime tools, porosity tools, chlorine logs, shale indicators, aluminum-activation logs, carbon-oxygen and calcium-silicon logs, sodium logs, magnesium logs, and devices for the detection of uranium. However, no one tool performed more than a few of these functions, whereas in a single hole many such parameters were important and failure to measure some of them sometimes led to an incorrect interpretation of the ones which were measured. One prior-art technique for increasing the capacity of the data link involved encoding the pulses produced by one data source as positive pulses and those produced by another source as negative pulses and then using this polarity difference at the surface to identify the data source. Not only did this technique have the obvious disadvantage of there being only two polarities and thus only two permissible data sources, but also the limited cable bandwidth and the networks used to couple the pulses to the cable conspired to produce pulse ringing and undershoots, which sometimes confused positive- and negative-signal information. As a result, careful adjustment by trained personnel was often required to obtain even marginally acceptable performance. In addition, the pulse-pileup problem became worse because now two data sources were sharing the limited-bandwidth cable, and they could interfere with each other as well amongst themselves. Another prior-art method for increasing the information capacity of logging cable without the above disadvantages involved the use of multi-conductor cable, which sometimes was driven as a high-frequency balanced transmission line. However, multi-conductor logging cable was not only expensive, but also it was still severely restricted in bandwidth in long lengths and possessed deleterious interactions between adjacent conductors. Also, because of its large diameter, it was difficult to use in small-diameter tubing or in deep boreholes and often had problems in high-pressure wells, particularly at the pressure interface at the top of the borehole. Thus, the use of a coaxial monocable with a single center conductor shielded by a load-bearing outer wall remained essential for many logging tools. This approach required that the single center conductor provided operating power for the subsurface equipment as well as a data link. Consequently, the limited cable bandwidth had to be shared between power sources and data sources, further complicating the design and adjustment of the pulse-coupling networks, particularly whenever bi-polar pulses from two data sources were used. These problems notwithstanding, even more information was imposed on the monocable. For example, casing-collar-locating pulses were applied to the cable, with their relatively long duration distinguishing them from other data sources. Similarly, commands were sent from the surface to subsurface equipment by varying a dc potential on the line. This latter technique was often used to switch between tools connected to the same cable to avoid the need for withdrawing the tool string completely from the hole to change tools whenever the required number of measurements caused the information capacity of the cable to be exceeded. However, inefficiently-used cable bandwidth was still limiting the flexibility and accuracy of the logging operation, causing the same formation to be logged several times in order to obtain all of the necessary information. Other prior-art approaches to this problem involved analog frequency-modulation (FM) techniques and tone-burst commands. These approaches at least avoided inaccuracies resulting from unstable cable attenuations. However, both analog FM and tone bursts as they were used in the prior art made ony limited use of the full capability of the cable. Analog FM in particular had the usual stability, accuracy and dynamic-range problems of any analog telemetry system, which were compounded whenever several subcarriers handling different data sources were required. In summary, the prior-art systems have been characterized by several disadvantages which were sufficiently severe to limit unnecessarily the quality and amount of data obtainable in the borehole-logging process. Many such systems were basically analog telemetry links, which were susceptable to the well-known problems in analog systems involving resolution, dynamic range, amplitude stability, signal distortion and noise. These problems were present in systems employing slowly-varying voltage or current signals, pulse-amplitude measurements or frequency-modulated carriers. Furthermore, even for data links which were basically pulse-counting systems that did not convey information by pulse amplitude, pulse-pileup effects and interferences between multiple data sources often limited instrument performance. Although sometimes counting rates and frequencies could be chosen initially or controlled by signal processing to provide an acceptable data quality, severe limitations were often still present with regard to tool-pulling speed, the number of data sources which could be handled simultaneously, the range of parameters over which precise operation was possible, and the ability of the surface equipment to control subsurface operation. Prior-art techniques used to overcome these problems often resulted in the need for precise adjustments and data interpretation by expensive, well-trained personnel, basically marginal operation, or the need for expensive, hard-to-use multi-conductor cable. SUMMARY OF THE INVENTION With the advent of inexpensive integrated circuits suitable for subsurface equipment, it now becomes feasible to construct an improved digital telemetering system for transferring data between subsurface instrumentation and equipment located in the vicinity of the surface. Digital systems of the form disclosed herein are characterized by high accuracy; independence of cable attenuation, distortion and noise; optimal use of the available cable bandwidth; ability to handle multiple data sources in a non-interfering manner; adjustment-free operation; and a high degree of flexibility including two-way communication along a single pair of conductors. The system is applicable to a monocable and can increase the accuracy, flexibility and information rates of multi-conductor cables as well. This digital telemetry system contains four major elements including: (1) an encoder located at the data source, (2) a modulator located near the encoder, (3) a demodulator located at the other end of the cable where data is to be received, and (4) a decoder located near the demodulator. The encoder arranges either analog or digital information to be telemetered into a series of digital values, which are communicated one bit at a time to the modulator and contain any necessary synchronization or identification patterns. The modulator places this serial data onto the cable in a suitable fashion for error-free reception by the demodulator at the other end of the data link. The demodulator reconstructs the serial data from the appropriate signals on the cable and provides digital data to the decoder. The decoder converts these digital signals into data bits, synchronizes itself to the data pattern and reproduces the original digital numbers that represented measured quantities at the other end of the data link. In one specific embodiment described herein, the data source consists of two pulse rates from two nuclear detectors placed in a subsurface instrumentation package, a casing-collar locating signal, and a temperature-sensitive resistance. The encoder digitizes the analog parts of this information and counts the input pulses during 0.5-second intervals and formats the resulting data into 16-bit words and 9-word frames, each of which includes a 7- or 16-bit synchronizing pattern. The data rate is 64 bits per second, implying that 2.25 seconds are necessary to transmit a complete frame. Thus, each detector has its average counting rate sampled and transmitted to the surface once every 0.5 seconds, and the data link can transmit all of the significant bits of the averaging counter together with temperature and collar-locating signals within a data rate of 64 bits per second. In that most prior-art systems required data rates near 10,000 pulses per second to transmit only the detector and collar-locating information, this data compression illustrates the large increase in efficiency in use of the limited cable bandwidth provided by downhole digital data processing coupled with a digital telemetry link. The encoder also changes the non-return-to-zero (NRZ) data into bi-phase data, which consist of a series of high and low signal levels, with there always being a transition from high to low or vice versa at the edge of a bit interval, and with there being a transition in the center of the bit interval only if a binary 1 is to be transmitted. Bi-phase data are relatively simple to decode and provide information within the signal to allow the decoder to reconstruct bit frequency and timing. In this embodiment, the modulator uses a 4096-Hz carrier frequency derived by binary division from a 16,384-Hz pilot tone generated at the surface and transmitted to the subsurface equipment over the same cable carrying the output data. Appropriate filtering, demodulating and coupling circuits permit both of these frequencies to be present on the same line without interference and also permit other carrier frequencies equal to other rational fractions of the pilot frequency to carry data from other sources simultaneously. Phase-shift-key modulation is used wherein the phase of the carrier is changed by 180° whenever the encoder data output changes state. Because the bi-phase code identifies data ones and zeros by the presence or absence of transitions, the phase shifts and not their absolute values contain the information. As a result, the ultimate data-rate capability of a 4-kHz carrier considerably exceeds the 64 bits per second actually used here, and the carrier frequency itself could also be raised considerably. Thus, this technique can be used to transmit data at rates exceeding 10,000 bits per second. In this embodiment, the demodulator consists of two synchronous rectifiers operated 90° out of phase in order to recover simultaneously data and bit-clock signals from the transmitted data. Synchronous rectification using carrier frequencies with binary relationships also helps to permit multiple carrier frequencies (or pilot tones) to be present on the same line without interference. The decoder in this embodiment then takes these data and clock signals and constructs from them at the end of each 0.25-second interval a 19-bit word, wherein 3 bits identify the data source and 16 bits indicate the state of the data provided by that source. Ratemeters containing digital filters then process the count-rate data contained in these words for visual display on a meter and by a recorder. An output for digital recording and computer processing is also available. Two methods are available for communicating from the surface to the subsurface instrumentation as well. Phase reversals in the pilot tone can easily provide occasional commands to the subsurface package. If higher bit rates are necessary in this direction, a second data link using a different carrier frequency can transmit data in the opposite direction from the first data link along the same wire. It is an object of the invention to provide an improved digital telemetering system for subsurface instrumentation. It is a further object of this invention to provide a system for telemetering data from a subsurface instrument package including subsurface digitizing and formatting of data to transmit information from several sources at reduced information rates. It is a further object of this invention to provide a digital system for telemetering data from a subsurface instrument package using a modulated carrier signal. It is a further object of this invention to provide a system for telemetering data from subsurface instrumentation utilizing bi-phase, phase-shift keying for modulation of a carrier signal. It is a further object of this invention to provide a system for telemetering data from subsurface instrumentation using multiple carriers of different frequencies to transmit data from multiple independent sources over a single wire in either direction. It is a further object of this invention to provide a system for telemetering data from subsurface instrumentation having a pilot tone for synchronizing transmitted signals between subsurface and surface and for transmitting commands. It is a further object of this invention to provide a system for telemetering data through a modulator utilizing tuned-transformer coupling and a demodulator utilizing synchronous rectification to permit several carrier frequencies or pilot tones to be present on the same line simultaneously without mutual interference. It is another object of this invention to provide a system for telemetering data from subsurface insrumentation having a two-way link to send commands down to the subsurface instrumentation and to send data up to the surface instrumentation. For a better understanding of the present invention, together with other and further objects thereof, reference is made to the following description taken in connection with the accompanying drawings in which preferred embodiments of the invention are illustrated, the scope of the invention being pointed out and contained in the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1a is the left-hand portion of a block diagram of one channel of a digital telemetering system for subsurface instrumentation; FIG. 1b is the right-hand portion of the block diagram shown in FIG. 1a; FIG. 2 is a detailed diagram of the preferred embodiment of the data encoder shown in FIG. 1; FIG. 3a is a detailed diagram of the preferred embodiment of the modulator and power conditioner shown in FIG. 1a; FIG. 3b is a detailed diagram of the preferred embodiment of the power supply and demodulator shown in FIG. 1b; FIG. 4 is a detailed diagram of the preferred embodiment of the bit synchronizer shown in FIG. 1; FIG. 5 is a detailed diagram of the preferred embodiment of the decommutator and clock-and-pilot-tone generator shown in FIG. 1; and FIG. 6 is a detailed diagram of the preferred embodiment of the pilot-tone and command receiver shown in FIG. 1. DESCRIPTION OF THE PREFERRED EMBODIMENT Turning to FIGS. 1a and 1b, there is shown an embodiment of one channel of an improved digital telemetering system 20 for transmitting data from subsurface instrumentation 107 to the vicinity of the surface over a cable 12. As will become apparent during the subsequent discussion, several such data links can apply signals to the same two-conductor cable 12, permitting the cable 12 to handle signals from multiple independent sources using several channels of this type. Furthermore, the direction of information flow need not always be from the subsurface equipment toward the surfacae but could be from the surface toward the subsurface equipment or between two or more equipment packages located beneath the surface. Although the specific configuration shown in FIGS. 1a and 1b is not essential to this invention, it will be used as a specific example for illustrating clearly the operation of this improved digital telemetering system 20. The basic data link comprises a data encoder 1, a modulator 9, a cable 12 to the surface, a demodulator 13 and a data decoder 14. The system may also comprise a power supply 19 and a power conditioner 11 for sending operating power from the surface to the subsurface equipment along the same cable 12 that transmits the data. The surface equipment, using a clock and pilot-tone generator 18 and a pilot-tone and command receiver 10 in the subsurface equipment, may further provide the subsurface equipment with a standard frequency signal, which can also be used for controlling the operation of the subsurface equipment from the surface. Data-conditioning circuits 17 located at the surface may process further the data-decoder outputs into analog and/or digital signals for recording, display or further processing, possibly by a digital computer. For the sake of illustrating a specific example, the data encoder 1 shown in FIG. 1a can receive potentially four types of input signals from the subsurface instrumentation 107. One type of input consists of bi-level data for which the average pulse repetition frequency contains the information. Such inputs can pass directly into digital counters 4, which totalize the number of such pulses during known time intervals as defined by other circuits in the data encoder 1. A second similar type of input differs from the first type only in that the amplitude of the input signals may be variable, requiring an amplifier-discriminator 2 to produce bi-level outputs suitable for digital counting in a counter 5. A third type of input consists of analog information either in the form of the amplitude or shape of relatively-fast pulses or in the magnitude of slowly-varying signals. After these signals pass through appropriate signal-conditioning circuits 3, which may include amplification, pulse shaping, gating and multiplexing, one or more analog-to-digital converters 6 produce a digital representation of the relevant analog quantity characterizing the measured value contained in the input signal. Clearly the same signal could enter both the variable-amplitude-pulse input and the analog-signal input. Finally the subsurface instrumentation 107 can supply to the data encoder 1 synchronization, timing or command pulses to indicate the happening of a specific event or to change the mode of operation of the data encoder 1 or the surface equipment. It will be clear to those skilled in the art that this invention is not restricted to the four types of inputs shown in FIGS. 1a and 1b. The essential characteristics of the input signals is only that they be capable of being converted to digital form, and telemetered either directly or after processing within the constraints of the information bandwidth. Thus, these four input types have been chosen only for clarity in illustrating the operation of the invention by giving a specific example and should not be viewed as constraining the general applicability of the invention to other signal types. The digital signals from the input signal-processing circuits comprising counters 4 and 5 and the analog-to-digital converter 6 and from the subsurface instrumentation 107 directly enter a sequencer 7. The sequencer 7 arranges the data inputs from several information sources into a single stream of serial, binary digits, or bits. These bits are generally grouped into words, which may be of fixed or variable length, with each word corresponding to a known information source. In general, words are further grouped into frames, each one of which has a word with a fixed data pattern forming a synchronization word, whereby it becomes possible to identify the position of a given data bit in a sequence of such bits beginning with the first bit in the synchronization word. From the knowledge of the position in the sequence of a given bit, it becomes possible to identify the information source responsible for that bit and the significance of the bit in encoding the value of the signal from that source. The above described operation of the sequencer 7 is only one possibility of several which are contained in this invention. The essential characteristic of the operation of sequencer 7 is the arrangement of the data bits from one or several sources into a sequence in which the function of a given bit is determined by its place in the sequence. All of the data bits from a given information source do not have to be contiguous, allowing them to be scattered throughout the sequence. Also, the data from the sequencer may be arranged as a multiplicity of serial outputs for use in multi-level encoding schemes or for telemetering to multiple independent data receivers. Furthermore, the synchronization function may be provided by a special signal. This signal could either be generated by the sequencer 7 in order to indicate to external circuits when the frame begins or could be received by the sequencer 7 from external circuits to command the sequencer to begin a sequence. Various combinations of these sequencing techniques could also be employed. The sequencer 7 further provides the reference time base for controlling the transmission of data, the input signal-processing circuits, and possibly the remainder of the subsurface instrumentation 107. This time base depends, in turn, on a reference frequency provided either internally by the sequencer 7 or received from the surface through the pilot-tone and command receiver 10. In the latter case, the pilot tone can also transmit commands from the surface, which can modify the operation of the sequencer 7 and/or can be passed on by the sequencer 7 to other subsurface equipment. The data output from the sequencer 7 enters the code generator 8, which in turn controls the modulator 9. The code generator may change the serial, binary data from the sequencer into a digital form which is more suitable for transmission over long lengths of cable. In the preferred embodiment, the code generator produces a bi-phase code containing two symbols for each data bit. This bi-level code always has a transition at the beginning of a bit interval and only has a transition at the center of the bit interval when the bit value being encoded is a 1. The bi-phase code has several advantages including the fact that only the presence or absence of transitions contain information, and no information is conveyed by the absolute value or sign of the signal. As a result, signal bandwidths become restricted, aiding in the design of transmission and decoding circuits, as well as reducing the susceptibility to noise. Furthermore, the code carries its own clocking and bit-synchronizing information in that every bit has at least one transition. As a result, synchronous decoding schemes become feasible and can adapt to changes in bit rates, delay times and noisy transitions, improving the bit-error rate while preserving a simple, low-cost mechanization. Although the bi-phase code has many advantages, it is not the only code suitable for this improved digital telemetering system 20. It does require a greater bandwidth for the data link because each bit is encoded into two symbols. Thus, if high data rates become a necessity, other codes such as NRZ and run-length-limited codes can be employed. Even higher information rates can be achieved with multi-level codes in which a single symbol encodes more than one bit. On the other hand, the need for very low error rates or unusually high noise levels may be indicating the need for codes containing error-detecting or error-correcting properties such as parity bits, block codes and cyclic codes. Also one can use codes wherein the data receiver interacts with the data transmitter in order to ask the transmitter to repeat incorrectly-received data or to send the same information more than once. These codes effectively use more than one symbol per bit and thus decrease the data rate for a fixed bandwidth. For many applications, the bi-phase code represents a reasonable compromise between these conflicting requirements. The modulator 9 receives the encoded digital data and any necessary clock frequencies from the code generator 8 and converts these signals into a form which can be applied to the cable 12. The modulator 9 used in the preferred embodiment provides phase-shift keying of a carrier frequency derived from a pilot tone generated at the surface. Because the bi-phase code is a two-level code, it can be converted into a modulated carrier in which the two levels are signified by two carrier signals differing only by a 180° phase shift. Phase-shift keying is also applicable to multi-level codes by making each code level correspond to a specific phase, allowing several levels to be contained in the full 360° of available phases. Phase-shift keying has the advantage that synchronous demodulation produces directly a signal with an amplitude uniquely related to phase so long as the carrier frequency and the demodulation frequency are equal. In that the frequency reference is produced at the surface and is available there, this equality is simply achieved, although it can also be obtained with circuits such as a phase-locked loop operating solely on the clocking information contained in the code. Furthermore, the use of a carrier frequency allows tuned circuits and synchronous demodulation to separate independent signal sources using different carrier frequencies, thus permitting several signal sources to share the same cable. The same technique also allows a two-conductor cable to carry both data signals and the pilot tone. Other modulation techniques are also feasible, including sending directly the pulses produced by the code generator 8. Frequency-shift keying, tone bursts, frequency modulation and amplitude modulation are typical of common data-transmission techniques which form a part of this invention. The modulator 9 signals travel up the cable 12 to the demodulator 13 in the vicinity of the surface. Because of its long length, the cable can considerably attenuate these signals, often by a factor of ten or more. In addition, the clock and pilot-tone generator 18 may apply a large-amplitude pilot tone to the cable 12 at this point, making the modulator 9 signals relatively small compared to the total signal level, including noise, on the cable 12 near the surface. Furthermore, more than one modulator 9 may be generating signals, reducing even more the relative amplitude of the particular signal to be detected. The primary function of the demodulator 13 is to receive these modulated-carrier signals and convert the selected one to bi-level data which represent accurately the output of the data encoder 1 in the subsurface instrumentation. In the preferred embodiment, the demodulator 13 provides this function in cooperation with the bit synchronizer 15, which forms a part of the data decoder 14. The demodulator 13 also contains circuits for adding the pilot tone from the clock and pilot-tone generator 18 to the line. The demodulator 13 in the preferred embodiment uses a tuned filter to separate the carrier signals from the pilot tone. It then employs synchronous rectification controlled by a demodulation-clock signal with a frequency and phase appropriately chosen by the bit synchronizer 15 to detect the output from a given modulator 9. An amplifier with a two-pole filter smooths the output of the synchronous rectifier to reject frequencies other than those required to pass information at the symbol rate, thus forming, together with the synchronous rectifier, a bandpass filter centered about a frequency equal to the frequency of the demodulation clock. Frequency dividers can derive this frequency from the same reference frequency that supplies the pilot tone which controls the subsurface carrier frequency, thus automatically centering the demodulator bandpass precisely at the carrier frequency to avoid the need for adjustable components and problems with temperature- and age-induced drifts in narrow-band tuned circuits. Furthermore, changing only the frequency of the demodulation clock allows the same circuit to handle a wide range of carrier frequencies. In the preferred embodiment using frequencies in binary steps from 1024 Hz to 8192 Hz with a 16,384-Hz pilot tone, the narrow bandpass of this type of demodulator allows all four of these carrier frequencies to be present simultaneously on the same cable. One or more demodulators 13 can be programmed to select any one of these frequencies simply by supplying it with a demodulation clock at that frequency. (The use of these specific frequencies is not an essential part of this invention, and they serve only to illustrate the operation of the improved digital telemetering system 20 with a specific example.) The phase of the demodulation clock must still be determined. Because of the instabilities in the propagation times over cables at variable temperatures with lengths potentially over 5 km, no stable phase relationship can be assumed between the pilot tone and the received modulated carrier. Thus, the demodulator 13 together with the bit synchronizer 15 must determine the proper phase of the demodulation clock from the received carrier signal itself. Because the bit synchronizer 15, as well as the remainder of the data decoder 14, in the preferred embodiment use purely digital techniques to provide a stable, adjustment-free, low-cost mechanization, the demodulator 13 contains discriminators at its output to convert the analog data provided by the filter amplifier into a bi-level form. In the preferred embodiment, the demodulator 13 contains two independent sets of synchronous rectifiers, filter amplifiers and discriminators, each of which is controlled by a different demodulation clock from the bit synchronizer 15. Both of these clocks have the same frequency and one is shifted in phase with respect to the other by a fixed 90°. It is inherent to the operation of a smoothed synchronous rectifier that if the phase of the demodulation clock with respect to the modulated carrier is chosen to give a null output, then the output from a smoothed demodulator operating from a clock shifted 90° in phase with respect to the first clock will provide a maximum output. Thus, if the bit synchronizer 15 adjusts the phase of the two demodulation clocks such that the smoothed output from the filter amplifier of the demodulator called the "carrier demodulator" is nulled, then the corresponding output from the second demodulator, called the "data demodulator," will be a maximum, providing an optimum representation of the transmitted information. In the preferred embodiment, this process involves adjusting the phase of the demodulation clocks until, on the average, the bi-level output from the discriminator connected to the "carrier demodulator," is equally likely to be a binary 1 as a binary 0. Other mechanizations of the demodulator 13 are also part of this invention. For example, analog phase-locked loops could control the phase of the demodulation clock and also its frequency if a pilot tone were not used. Various techniques using tuned circuits are also well known to those skilled in the art for detecting phase reversals in a carrier frequency. Furthermore, the filter amplifier need not use two poles but could employ other techniques such as one or multiple poles, gated integration, etc. Finally, if other modulation schemes were used in the modulator 9, then appropriate demodulators 13 would be needed. Included therein are tuned amplifiers for tone-burst detection, ratio and other detectors for FM demodulation, diode detectors for AM demodulation, and multi-level discriminators or analog-to-digital converters for multi-level codes. The data decoder 14 not onnly supplies the demodulation clocks to the demodulator 13 but also converts the demodulator 13 output into serial data bits along with a correctly-timed bit clock signal. The decommutator 16 within the data decoder 14 then examines this serial stream of reconstructed data bits to locate the synchronization word and uses the location of each data bit with respect to the synchronizattion word to identify the significance of each bit. This decommutation function results in output digital words arranged to convey both the source of a measured parameter and its value. Subsequent data-conditioning circuits 17 can then process selected output words into a form for recording, display or further computation of either an analog or digital nature. In the preferred embodiment, the bit synchronizer 15 is operating on bi-phase data characterized by transitions at every bit edge at a known frequency determined by binary division from the frequency of the pilot tone. As a result, a digital phase-shifting circuit can select an appropriate phase for a signal, called "bit clock," such that this signal makes transitions at the average time of tht symbol transitions of the received data bits. In order to avoid ambiguous operation for large numbers of data 1's, which have transitions at the center of the bit interval as well as at the boundaries, the synchronization word contains zeros, and the bit synchronizer 15 requires that there always be a detected symbol transition within a reasonable interval centered about a transition in the bit clock. Other techniques for generating a bit-clock signal are also a part of this invention. The pilot tone is not essential, and a phase-locked loop could determine the frequency as well as the phase of the bit clock. External synchronization signals transmitted directly from the subsurface equipment can facilitate the bit- and frame-synchronization function, and other synchronization techniques might be required or be more appropriate if bi-phase coding of the data were not used. Turning now to FIG. 2, there is shown a detailed diagram of the data encoder 1 for one of the preferred embodiments. In this particular embodiment, the subsurface instrumentation 107 consists of a detector of neutrons that produces neutron count 114 pulses, a detector of gamma rays that produces gamma count 118 pulses, a locator of casing collars that produces the CCL signal 112 and a temperature-variable resistance 126. These signals from the subsurface instrumentation are processed as follows. The variable-amplitude casing-collar-locator signal 112 is applied to a pulse-amplitude discriminator circuit 113. The bi-level neutron count pulses 114 and gamma count pulses 118 are applied to input circuit 115 and gate circuit 120, respectively. The temperature-variable resistance 126 is connected to a resistance-controlled oscillator 128. These four signals make up the information about the subsurface environment that will be encoded and transmitted to the surface in this embodiment of the invention. The 16,334-Hz clock from the pilot tone and command receiver 10 provides the input signal to the timebase countdown logic 140 that controls the encoding of the input signals 112, 114, 118 and 126 into a coded binary signal that is applied to the modulator 9. The encoding of input signals involves three major steps. First the input information is converted into digital numbers, then the numbers are arranged into a sequence of bits, and then this sequence of bits is encoded into signals compatible with the modulator 9. Conversion of the input information from the detector of neutrons consists of the application of the neutron count signal 114 to the neutron-counter input gate 115, whereby counts are accumulated within the 15-bit neutron counter 116 for 0.5 seconds, after which the count in neutron counter 116 is transferred to neutron shift register 134. Shortly therafter, the neutron counter 116 is reset to zero by the signal clear N 162 and the counting process begins again. In this manner, the number of neutron count pulses that occurred in an 0.5-sec interval becomes a 15-bit binary number located within neutron shift register 134. Signals associated with input gate 115 in addition to neutron count 114 include sample N 142 that is used to control the duration of counting of the neutron count 114 pulses to always be 0.5 seconds by blocking application of the neutron count 114 pulses for 0.25 seconds during the time that the synchronizing pattern is being transmitted, and load N 144 that briefly blocks application of counts to the neutron counter 116 while the 15-bit neutron-count number is being transferred to neutron shift register 134. This brief blocking of application of counts helps to assure that the transferred number is a correct representation of the number of neutron counts, undisturbed by counting transients within neutron counter 116. A neutron over-range signal 155 blocks all further counts into neutron counter 116 when the count reaches 32,767 pulses. This prevents confusion of data if unexpectedly high counting rates are encountered by causing a count-of-zero indication whenever more than 32,767 neutron counts occur in 0.5 seconds. The casing-collar-locator signal 112 is converted to a bi-level signals within amplitude discriminator 113 and causes a logic 1 to be temporarily stored in CCL memory 164 whenever it occurs. The CCL memory output is loaded in the most-significant bit of neutron shift register 134 at the same time as the neutron count 114 is loaded into that register, after which CCL memory 164 is reset by clear N 162. The result of the process described above is thus, that a 16-bit number comprising 15 bits of neutron count data and one CCL bit has been constructed and placed in neutron shift register 134. The information from the detector of gamma rays, the bi-level signal gamma count 118, is converted into a 16-bit number describing the number of gamma rays detected in an 0.5-second interval by a process involving input gate 120, OR gate 122, gamma counter 124, and gamma shift register 136. Gamma count signals 118 are allowed to enter gamma counter 124 via gates 120 and 122 for 0.5 seconds, after which additional counts are blocked by application of the signal load G 148 to input gate 120. Load G 148 serves to prevent incorrect transfer of gamma counts into register 136 in the same manner that load N 144 serves for neutron count data. Load G 148 causes the 16-bit number in gamma counter 124 to be loaded into the 16 bits of gamma shift register 136, after which the counter 124 is cleared to zero by clear G 160. In order to prevent ambiguous data in the event of unexpectedly large rates of gamma count 118 signals, the gamma overrange signal 156 blocks further counting in gamma counter 124 whenever more than 65,537 counts have entered gamma counter 124 by application of said overrange signal 156 to the input gate 120. The signal sample G 146 applied to input gate 120 blocks counting of gamma count 118 signals for 0.25 seconds during each 2-second interval to permit counting of the temp count 150 of the resistance-controlled oscillator 128 via input gate 130 and OR gate 122 during this 0.25-second interval. Application of temp count 150 pulses to gamma counter 124 is controlled by the application of the signal sample G* 154 to input gate 130. This measurement of the oscillator 128 output serves to digitally encode the value of the temperature of the environment of the subsurface equipment. The digital representation of temperature is then transferred to gamma shift register 136 by load S 152, which signal also blocks counts from the oscillator 128 to avoid transfer of incorrect data as discussed above in connection with the reasons for connection of the signal load N 144 to input gate 115. The signal temperature overrange 170 prevents a malfunction of the temperature indicator from affecting the sync code. The special sequence of bits used to synchronize the date decoder 14 to the transmitted bit sequence is inserted into the data encoder output pattern using the sync generator 132. The synchronizing bits from the sync generator are inserted into the data stream from the encoder once each 2.25 seconds. The 16-bit neutron word from the neutron shift register 134 and the 16-bit gamma word from the gamma shift register 136 are alternated, one word each 0.25-second interval, four times between sync patterns. Thus, a data frame comprises nine 16-bit words, arranged in the order S N G N G N G N G S, etc. The sync word, S, alternately contains the pattern 0100011111111111, and 01000110 followed by 8 bits of temperature-count data. All count data are transmitted most-significant-bit first. The numbers are arranged in a fixed sequence of bits under control of timing signals produced by the time-base countdown logic 140 which operates in response to the 16,384-Hz clock from the pilot tone and command receiver 10. The sequence of bits is determined by the time at which data words are loaded into the shift registers 134 and 136, and by the action of gate 172. The outputs of the three sources of data are combined in NOR gate 138 and applied to code generator 8. The signals controlling the neutron data are load N 144 and clear N 162. Load N 144 is 60 μs wide and is followed 60 μs later by clear N 162, also 60 μs wide. These signals are delayed 0.25 sec, or one 16-bit word time, from the corresponding signals controlling the gamma data-load G 148 and clear G 160. The temperature count is inserted into gamma shift register 136, just before the sync word is transmitted, by load S 152. Clear G 160 happens immediately following load S 152, in addition to its occurrence following each load G 148, to prevent combining temperature count 150 with gamma count 118 signals. The neutron and gamma shift registers and sync generator 132 are continually shifted at a 64-Hz rate by the signal bit clock 174. By proper timing of the load signals and by the shifting zero's through the registers, it becomes possible to combine the register outputs in NOR gate 138. The sync patter is gated into the data stream through gate 138 and gate 172 by the signal sync 158 for convenience in handling the alternate 16-bit sync and 8-bit sync/8-bit temperature words. The code generator 8 consists of a NAND gate 166 and a J-K flip-flop 168, operating in conjunction with a 128-Hz signal (twice the bit-clock frequency). The output from the NAND gate 166 is a logic 1 during the first one-half of each bit interval due to the signal 64-Hz* connected to the input of gate 166, and is equal to the value of the data stream during the second half of each bit interval due to the connection from the NOR gate 138 to the second input of NAND gate 166. The J-K flip-flop 168 changes state only when its J and K inputs are logic 1 and a clock input is applied. This results in the output SYMBOL (and its logical complement SYMBOL*) changing state at least once each bit interval, and changing a second time whenever the data signal is a logic 1. The code thus produced is termed bi-phase code. Other designs for this encoder function can be employed and form a part of this invention. Other arrangements of counting circuitry, analog-to-digital conversion circuits, and computing or processing circuits can be added if required. Turning to FIGS. 3a and 3b, one sees, respectively, a detailed diagram of the modulator 9 and demodulator 13 of the preferred embodiment. These figures also illustrate the method for transmitting operating power for the subsurface equipment over the same cable 12 from a power supply 19 to a power conditioner 11. The modulator 9 receives three binary input signals from the data encoder 1. The CARRIER CLOCK, which has a frequency of 4095 Hz in this example, is a continuous square wave defining the carrier frequency. A transformer 35 with a primary tuned by capacitors 21 and 22 to 4096 Hz converts this signal into mostly-sinusoidal currents applied through the transformer 35 secondary to the cable 12. The phase of these sinusoidal currents depends on whether transistor 28 or transistor 34 provides the return path for the currents introduced at the center tap of the primary winding of transformer 35. The state of the other two input signals, namely SYMBOL and its logical complement, SYMBOL*, determine this conduction state. Transistor 25 with components 23, 24, 26 and 27 permits SYMBOL* to control the conduction state of transistor 28, whereas transistor 31 with components 28, 30, 32 and 33 allows SYMBOL to switch transistor 34. Thus, the modulator 9 under the control of the data encoder 1 can reverse the phase of the carrier signal applied to the cable 12 as the data state changes from a binary 1 to a binary 0, or vice versa, producing phase-shift-key modulation of the carrier. Because of the desire to avoid noise and other errors caused by reflections traveling back and forth along the cable 12, the impedance seen by signals traveling out of the cable 12 into the modulator 9 should be approximately equal to the characteristic impedance of the cable. This criterion will also insure that the pilot-tone generator 18 can develop a detectable signal across the cable 12 at the modulator 9, without having to supply excessive signal levels at the surface end of the cable 12. Finally the need to connect several modulators in series to allow for the connection of several independent tools to the same cable also requires a defined impedance looking back into the modulator 9 and also a method for permitting signals with frequencies other than that defined by the CARRIER CLOCK for a particular modulator to pass unhindered through that modulator. The configuration shown in FIGS. 3a and 3b satisfies these impedance and signal passage requirements. The secondary of the transformer 35 referred to the primary appears as a parallel-tuned circuit resonant at 4096 Hz in series with the cable. Thus, it presents a low impedance to other frequencies, which are at least a factor of 2 removed from 4096 Hz, including the 16,384-Hz pilot tone and any other carrier frequencies. If the lower end of the secondary of transformer 35 is connected to an impedance equal to the characteristic impedance of the cable 12, the voltage developed across this impedance at frequencies other than those near 4096 Hz will not be substantially changed by the presence of the secondary of transformer 35. The series-turned network consisting of components 36, 37 and 38 equalizes the impedance at 4096 Hz, so that the impedance at the input of the modulator 9 equals the characteristic impedance of the cable 12 for all carrier and pilot-tone frequencies whenever the cable 12 characteristic impedance loads the output of modulator 9 passing to other subsurface instruments. This load aan either be an appropriate passive network or the input to another modulator associated with other subsurface instrumentation. The transformer 35 also isolates the dc potential of the line from the modulator 9 input circuits and the data encoder 1. As a result a 38V potential difference can exist between the center conductor and outer shield of the cable 12 and the shield can still be referenced to ground potential as required by the usual methods for cable spooling and handling. A simple power conditioner 11 consisting of zener diodes 45 and 46 and an emitter follower 44 can then supply +10-V power to the subsurface equipment directly from the cable 12. Filtering is provided by components 40, 43, 48, 49 and 50 to avoid transient loads placing noise on the cable, whereas diode 39 protects against reversed polarities on the cable 12 and momentary open circuits. Resistors 41 and 42 supply current to zeners 45 and 46 and divide down the line voltage to generate the 31-V output. Diode 47 provides conpensation for thermally-induced drifts in the emitter-base voltage of emitter follower transistor 44. Other power-transmission systems besides a dc power supply from a part of this invention. The only essential characteristic of the power system is that it use frequencies other than those used for signal transmission. In that case isolation circuits based on frequency such as those shown in FIG. 3a can separate power-related frequencies from signal frequencies. Although a dc power system clearly uses different frequencies than the 4096-Hz and 16,384-Hz signal frequencies assumed for the preferred embodiment, a power system using 50-Hz, 60-Hz or 400-Hz power-transmission frequencies also satisfies this criterion and would function in a similar manner to the dc system shown in FIG. 3. Other power conditioners 11 could also be used depending on the power-transmission frequency and include dc-to-dc converters and transformer-coupled rectifiers. The modulated carrier signals travel from the modulator 9 to the surface over cable 12 and enter the demodulator 13. The demodulator 13 consists of a filter 108, a data demodulator 109, a carrier demodulator 110 and discriminators 111. The signals first enter the filter 108, which separates the pilot tone from the modulator signals and terminates the line for all of these frequencies in its characteristic impedance. In the preferred embodiment, the clock and pilot-tone generator 18 produces a square-wave signal called the 16,384-Hz CLOCK. This signal is applied to the cable 12 through a capacitive divider 52 and 53, which is series resonate at 16,384 Hz with inductor 51 and blocks the dc potentials on the cable 12 from the pilot-tone generator 18. The capacitive division ratio, the value of resistor 54, the source impedance of the pilot-tone generator 18, and the losses in inductor 51 provide an impedance at 16,384 Hz equal to the characteristic impedance of the line. A parallel-tuned circuit consisting of capacitor 56 and inductor 55 resonant at 16,384 Hz isolates the remaining demodulator 13 circuits from the cable 12 at this frequency. Thus, these tuned circuits terminate the cable 12 in its characteristic impedance at 16,384 Hz, and furthermore attenuate the pilot tone in the remainder of the demodulator 13. In addition, the series-resonate circuit reduces the higher harmonics from the 16,384-Hz CLOCK to yield a sinusoidal pilot tone on the cable 12. At frequencies far removed from 16,384 Hz the series-resonant circuit including components 51, 52 and 53 becomes a high impedance, whereas the parallel-resonant circuit of components 55 and 56 becomes a low impedance. If the output impedance of the power supply 19 is low for carrier and pilot-tone frequencies and if resistor 58 is large compared to resistor 57, then making resistor 57 equal to the characteristic impedance of the cable 12 will terminate the cable 12 with its characteristic impedance for those frequencies. This resistor will also develop a voltage from the modulated-carrier currents traveling up the cable 12, which can pass virtually unhindered through the parallel-resonant circuit of components 55 and 56 and can then be distributed to as many other demodulators as there are carrier frequencies to be detected. Components 58, 59, 60 and 75 also restrict the bandpass for signals proceeding further into the demodulator 13 in order to reject both high- and low-frequency components of noise and electrical interference. The filtered signals from cable 12 enter the data demodulator 109 through capacitor 60 and carrier demodulator 110 through capacitor 75. These capacitors block the dc potential on the cable 12 produced by the power supply 19. Solid-stage switches 61 and 76, shown schematically in FIG. 3b as double-pole, double-throw mechanical switches, then use the demodulation clocks produced by the bit synchronizer 15 to rectify synchronously the filtered carrier signals. The demodulation clocks for the data demodulator 109 are called DATA PHASE and DATA PHASE*, whereas those for the carrier demodulator 110 are named CARRIER PHASE and CARRIER PHASE*. The rectified output of solid-state switch 61 in the data demodulator 109 enters a one-pole filter amplifier consisting of integrated circuit 70 with feedback and input components 62, 63, 64, 65, 66 and 67. A second pole provided with components 68 and 69 further smooths the amplifier 70 output. Amplifier 85 with components 77, 78, 79, 80, 81, 82, 83 and 84 provides the same function for the rectified signals from solid-state switch 76 in the carrier demodulator 110. The solid-state switches 61 and 76 alternately connect the outputs of the coupling capacitors 60 and 75 to the inverting and non-inverting inputs of amplifiers 70 and 85. The amplifier 70 or 85 input not connected to the coupling capacitor 60 of 75 is tied to a reference potential which in the preferred embodiment of FIG. 3b is +5V. The demodulation clocks reverse the state of the switches 61 and 76 twice during each period of the carrier frequency to be detected, so that for 50% of each period the switches 61 and 76 are closed in the manner shown in FIG. 3b and for the remaining 50% they contact the other poles. As a result, the average output voltage from the filter amplifiers 70 and 85 equals the 5-V reference voltage plus voltage proportional to the amplitude of the filtered carrier signal with the same frequency as the demodulation clocks. The low-pass filters prevent transients with a zero average value produced by switching action on other carrier frequencies with a binary rational-fraction relation to the pilot tone from reaching the outputs of the data demodulator 109 or the carrier demodulator 110. The proportionality constant between the average output voltage above the reference voltage and the amplitude of the filtered carrier signal at the input depends on the phase of the demodulation clocks with respect to the filtered carrier signal. This dependence is approximately cosinusoidal so that the magnitude of the output is maximum for in-phase rectification, and in that case a phase change of 180° will reverse the polarity of the output signal. It also follows that if the demodulation clock is 90° out of phase with respect to the carrier signal, then that signal output vanishes and remains zero even if the carrier phase changes by 180°. Thus, the operation of the bit synchronizer 15 which nulls the output of the carrier demodulator 110, which is driven 90° out of phase with respect to the data demodulator 109, will ensure maximum signal excursions at the output of the data demodulator 109 in response to phase reversals of the carrier signaling changes in state of the code-generator 8 output. The discriminators 111 convert the output signals from the data demodulator 109 and the carrier demodulator 110 into a bi-level form. The data discriminator 74 producing the DATA signal indicates whether the data-demodulator 109 signal is above or below the 5-V reference and thus whether the carrier signal is in phase or 180° out of phase with the DATA-PHASE clock. The reference provided by resistors 71 and 72 for the discriminator 73 producing the DATA-HIGH signal is slightly above +5 V so that this discriminator 73 can indicate whether the amplitude of the carrier signal is sufficient for reliable data decoding. The discriminator 87 producing the CARRIER signal is also referenced to +5 V and determines whether the ouput of the carrier demodulator 110 is high or low. The other discriminator 86 producing LOCK* indicates whether the output of the data demodulator 109 is above or below the output of the carrier demodulator 110. This output aids the bit synchronizer 15 in establishing the proper phase for the demodulation clocks. These discriminator 111 signals proceed to the data decoder 14 shown in FIG. 4 for the preferred embodiment. The bit synchronizer 15 operates the demodulators 109 and 110 to recover serial data and bit clock from the modulated carrier signal transmitted over the interconnecting cable 12. The logic diagram in FIG. 4 illustrates the detailed design of the bit synchronizer in this embodiment. The bit synchronizer 201 comprises the three major functional elements, enclosed within dashed lines in FIG. 4, of the demodulation clock generator 210, the bit-clock generator 211 and the data decoder 209. The operation of each of these three logic circuits depends upon the data modulation method used in this embodiment. Because 180° phase-shift keying is used for modulation, the demodulation clock may be synchronized to the carrier phase by causing the switches 76 in carrier signal demodulator 110 to change position at the time the carrier signal passes through a maximum, in which case the data demodulator 109 will produce a maximum signal amplitude, providing optimal signal recovery, if it samples the carrier 90°, or 1/4 cycle of the 4096-Hz carrier clock, later. Because bi-phase mark encoding is used, the value of the first symbol in each bit is known to be opposite from the value of the second symbol in the preceeding bit. Thus the value of the carrier phase --0° or 180° -- can be combined with the average value of carrier 178 to instruct the phase-shifting circuits within the demodulation clock generator 210 to approach a null condition. Because bi-phase mark data always has a transition at the edge of a bit time, the bit clock may by synchronized to the received string of symbols by measuring the average value of data 176 for a time interval centered on the expected time of transition at the end of the second symbol in the bit. By sampling the value of data 176 midway through the symbol, the phase of the bit clock signal may be adjusted in the direction required to make the average value of data 1761/2. Measuring the average values for a narrow interval that occurs with the bit-clock period eliminates the effect of the data-1 transitions in the middle of the bit; furthermore by assuring that data-zeros are present in the sync word and by designing the slew-rate of the bit-clock phase-adjusting loop appropriately, we can assure that the bit clock is properly synchronized to data within one 2.5-second data frame. The bit-clock generator 211 will thus adjust the signal bit clock 208 into synchronism with the data stream within one frame. Because the data bit comprises different symbols if the data value is a logic 1, and identical symbols if data value is zero, comparison of the first and second symbols in each bit using an exclusive-OR gate will produce serial data 206 that is valid during the second symbol of each bit, and is zero during the first symbol of each bit. Sampling this data at the proper time produces serial data for the demodulator. The logic shown within the demodulation clock generator 210 operates upon the 65,536-Hz clock signal 175 using a controlled divide-by-four 188 coupled to a 4-phase clock generator 190 to generate the clock phases required to operate the demodulator 13 shown in FIG. 3. The 4-phase clock generator 190 is a conventional 2-bit feedback shift register implemented with D-type flip-flops with the negation output of the second flip-flop connected to the D input of the first. Control of generator 190 is performed in the controlled divide-by-four 188 circuit, where the 65,536 Hz 175 is divided by four. Control of 188 is by the skip-1 and add-1 signals, which cause circuit 188 to skip or delay by one cycle of the 65,536-Hz clock, corresponding to a retardation or advance of 211/4° in the phase of the clock generator 190 output, respectively. The skip signal causes the controlled divide-by-four 188 to pause for four cycles of the 65,536-Hz 175 clock to produce a 90° phase shift in the demodulator clocks. The add and skip signals are produced by the circuit comprising synchronizer 196, up/down counter 198, exclusive-OR gate 182, and D-type flip-flop 193. This circuit measures the average value of the signal carrier 178 during the time that the carrier sample signal from the bit-clock decoder 203 is present. The average is measured by causing carrier 178 to control the direction in which counter 198 counts, while the counting is controlled by an enable signal (carrier sample) and a clock from the bit clock generator 211 to be 3 counts during the first symbol of each bit. The direction in which counter 198 moves in response to a logic 1 level at the carrier 178 input is determined by using flip-flop 193 to store the value of data 176 the immediately-preceding symbol, and using this information in an exclusive-OR arrangement with data 176 to set the direction. Skip or add pulses are generated by synchronizer 196 whenever up/down counter 198 reaches the minimum 0 or maximum 15 state, respectively. Synchronizer 196 also resets counter 198 to 8, the middle of its range, when a skip or add is produced. The shift-90 signal is required to avoid a situation where the average value of carrier 178 is zero not because it is nulled, but rather because it is swinging from one limit to the other. This anomalous pattern can exist stably under certain data patterns. The shift-90 signal is generated by exclusive-OR gate 180, control 184, up-down counter 185 and synchronizer 186 in a manner similar to that described for the skip/add logic above, except that the criteria for skip-90 is the occurrence of the signal LOCK* 177 when data 176 is a logic 1 during seven successive bits. When LOCK* 177 and data 176 are both logic 1 during a defined time within a bit, control 184 causes counter 185 to count up; if LOCK* 177 is low when data 176 is high, counter 185 counts down. If counter 185 reaches the minimum-count value of zero, then control 184 sets counter 185 to 7; if counter 185 reaches the maximum-count value of 15, then control 184 sets counter 185 to 7 and generates a shift 90 signal. The bit clock generator 211 uses the 4096-Hz DATA PHASE signal from demodulation clock generator 210 to produce the signal bit clock 208 properly synchronized to the appropriate data transitions. Divide-by-four 200 produces a 1024-Hz signal that is applied to a 4-bit counter 202. The bit clock frequency of 64 Hz is the output from the most-significant bit of counter 202. The phase of counter 202 is adjusted using 4-bit counter 204 to measure the average value of data 176 during the bit-edge transition time, and to correct the phase of bit-counter 202 by forcing bit-counter 202 to the correct value at a specific time. Flip-flop 194 and exclusive-OR gate 183 allow the phase-control counter 204 to increment only after the data transition has occurred. If the data transition and bit clock 208 are synchronized, then at the time that counters 202 and 204 are forced into agreement, the two counters will agree and no phase adjustment will occur. Data decoder 209 produces serial data 206 by the exclusive-OR of the two symbols in each bit. Serial data 206 is thus always 1 when the second symbol of a bit is in flip-flop 192, because this means that the first symbol of the preceding bit is in flip-flop 191. Serial data 206 is equal to the recovered data signal one-half a bit time, or one symbol clock, later when the value of both the symbols corresponding to one bit are in flip-flop 191 and 192. The decommutator 16 receives the serial data 206 and the synchronized bit clock 208 signals from the bit synchronizer 15, and produces 19-bit data words with 16 bits of information and a 3-bit data-source identification accompanied by a strobe pulse for timing for use by data conditioning circuits 17. FIG. 5 is a block diagram of the decommutator 16 and the clock and pilot-tone generator 18. Bit clock is counted down in counters 216, 217 and 218 to identify bits, words and frames, respectively. The word counter 217 is decoded in decoder 219 to produce the data identification code and strobe pulse for the data conditioning circuits 17. The frame counter 218 keeps track of the alternating pattern of one's and temperature data and inserted adjacent to the sync code. The counters 216, 217 and 218 interact with the mode control 226 to initially find sync in a SEARCH mode of operation, and then to confirm that synchronism between the counters 216, 217 and 218 and the serial data stream is maintained in a MONITOR mode. The 16-bit shift register 214 assembles the 16 bits of serial data into parallel form for use by sync comparator 220 and by the data conditioning circuits 17. The sync comparator 220 compares each bit of register 214 with the sync pattern and presents the results of the comparison on 16 lines to scanner 222. When enabled, scanner 222 sequentially examines the 16 inputs from sync comparator 220 and generates one pulse for each mismatch for counting by the sync-error counter 224. The sync error counter 224 provides mode control 226 with signals about the number of bits not matching the sync pattern - 0, 1 or more than 1. The mode control 226 enters search mode and enables once each bit time scanner 222 if the error count exceeds 1. When the 16-bit pattern in register 214 matches the sync pattern with zero errors, the mode control 226 presets counters 216, 217 and 218 and disables scanner 222 for one frame (144 bits). Scanner 222 is then re-enabled, and if zero errors are again observed the sync-bad output 212 becomes false and the monitor mode is entered. If any errors are detected, search mode is re-entered. The monitor mode remains in effect as long as each frame, when scanner 222 is enabled; no more than one count is registered by sync-error counter 224 as a result of comparator 220 and scanner 222 examining the agreement between the sync pattern and the 16-bit data word that should contain sync. The clock and pilot tone generator 18 comprises a 1.0485-MHz quartz-crystal-stabilized oscillator 228 and a binary counter 230. This produces the 16,385-Hz logic-level signal that synchronizes the surface and subsurface equipment. The 1,0486MHz clock provides the time base for all clock signals used for the data decoder 14 circuits. Although the carrier frequency being an exact binary multiple of a clock frequency available at the surface is not essential to this invention, this relationship, has simplified the design of many parts of this improved digital telemetering system 20. FIG. 6 illustrates the method whereby the pilot tone carrying this frequency information from the surface can be received at the subsurface end of the cable 12 to provide a subsurface reference frequency for the generation of the carrier frequency. A series-tuned circuit 88 and 89 resonant at the pilot-tone frequency of 16,384 Hz in the preferred embodiment selects this signal from amongst a multiplicity of signals on the cable 12. Because at this end of the cable 12 the carrier signals can be considerably larger than the pilot tone owing to cable 12 attenuation, it is necessary to enhance signals at the pilot-tone frequency with respect to signals at the carrier and other noise frequencies. The resulting signal enters through resistor 90 a clamping circuit consisting of diodes 92, 93, 95 and 96 referenced to +10 V. The current in resistors 94 and 97 place diodes 92 and 96 in conduction to prevent resistor 90 from loading the tuned circuit 88 and 89 too severely for small pilot-tone signals. Capacitor 91 attenuates high-frequency noise. The clamping-circuit signal is applied to a Schmitt-trigger circuit consisting of components 98, 99, 100, 101, 102 and 103. This circuit uses positive feedback through capacitor 102 to provide a distinct output whenever its input signal crosses its threshold voltage with a value given approximately by the +10 -V reference. These standarized pulses enter a phase comparator 104, which forms a part of a phase-locked loop. The other components in the phase-locked loop are a filter 105, which provides stability against loop oscillation and smoothing of noise, and a voltage-controlled oscillator 106, which generates the 16,384-Hz CLOCK. A binary divider 117 generates the 4096-Hz CARRIER CLOCK from the 16,384-Hz CLOCK. The output of the Schmitt-trigger circuit 99 and 100 could be used directly as the source of the 16,384-Hz CLOCK if the cable 12 were free of noise. However, the presence of noise, including occasional poor connections in slip rings usually connecting the cable 12 to the surface equipment, would then cause an unacceptable jitter in the clock signal. The use of a phase-locked loop with a slow response time will smooth these variations, providing a nearly jitter-free clock signal for the subsurface equipment. A second use of the phase-lock loop is as a command detector. If the surface equipment suddenly reverses the phase of the pilot tone, then the phase comparator 104 will produce a large transient at its output to bring the 16,384-Hz CLOCK back into phase synchronism with the pilot tone. This signal from the phase comparator 104 can signal the receipt of a command to the subsurface equipment.

An improved digital telemetering system for conveying information from a subsurface measuring device to a receiving station located at the other end of the cable used to lower and retrieve the measuring device is disclosed. The information being telemetered is converted into digital form within the subsurface measuring device and is communicated as digital numbers over the telemetry link for recording, display and interpretation at the receiving station. A single insulated wire within the hoist cable can convey all signals and the electrical power to the subsurface equipment. The outer sheath of the hoist cable provides the return circuit. A decoder circuit located within the surface equipment recovers the data and converts them to useful information. The system can be adapted to handle data from several sources simultaneously and can act as a communication link in both directions without the need for added conductors in the hoist cable.

RELATED APPLICATION This application claims priority in part to provisional application Ser. No. 60/607,950 filed on Sep. 9, 2004. FIELD OF THE INVENTION This invention relates to power converters, and more particularly to switch-type power converters designed for use in recreational vehicles as a regulated power supply for DC load devices and as a battery charger. BACKGROUND OF THE INVENTION As used herein, the terms “recreational vehicle” and “RV” should be construed to embrace motor homes, trailers, campers, van conversions, fifth wheels, boats, and similar products. The common characteristic of these recreational vehicles is an electrical system incorporating one or more batteries to provide power for DC load devices such as lights, refrigerators and motors. The more sophisticated recreational vehicles may also have alternating current systems and AC load devices such as stoves, televisions, microwaves and heating and ventilating systems. The AC load devices are typically powered from a 115 volt AC line voltage source brought to the recreational vehicle through a power cord and plug. Some recreational vehicles also carry generators powered by gas or diesel engines and capable of producing as much as 20 or more kilowatts of AC power. It has become common to install power converters in recreational vehicles. A typical power converter converts 115 vac to 13.6 vdc and charges the RV battery or batteries as necessary. It has become more and more common to use “switch type” power converters rather than linear converters. There are numerous reasons for this including a substantial weight savings. Switch type power converters, often simply called “switchers” or “switching” power converters, typically use one or two power switching semi-conductor devices such as field effect transistors (“FET's”) and a controller such as the Unitrode UC 3846 for operating the semi-conductor devices in a variable duty cycle mode. Such devices further typically include a step-down transformer and a smoothing circuit between the transformer and the regulated output voltage terminal. A designer of such converters faces numerous issues including heat dissipation, noise generation, tolerance to unstable or excessive supply voltages and protection of the expensive circuit components found therein. The manufacturer of such devices faces these and other issues including warranty claims based on alleged defects when, in fact, field failures are often caused by improper use such as (1) accidentally connecting the converter input to an excessive voltage source such as a 220 vac line or an improperly regulated or runaway generator; and (2) accidentally connecting the RV battery in reverse polarity Power converters which deal with some of these issues are described in U.S. Pat. Nos. 5,600,550 and 5,687,066 issued to James Cook in February and November, respectively, of 1997 and assigned to Progressive Dynamics, Inc. of Marshall, Mich. The power converter described in the '550 patent is of the switch type in which the switch includes two FET's operating in a push/pull fashion under the control of an integrated circuit controller such as the Unitrode UC 3846. The converter further comprises a fan powered by the converter output and a pair of thermistors mounted on a large heat sink along with the FET's. One of the thermistors is used in combination with a set-point device to turn the fan on and off and the other is used to shut the controller down in the event temperature reaches an extreme or intolerable level. U.S. Pat. No. 5,687,066 describes a converter identical to that of the '550 patent but adds overvoltage protection. This feature is provided by a Zener diode to sense an overvoltage condition in the dc output of a diode rectifier bridge used to convert an ac line voltage to dc. If the rectified supply voltage exceeds a predetermined limit, the Zener diode conducts and quickly sends a signal to a shut down pin of the Unitrode controller to prevent the controller from turning the FET's on. This protects the FET's from damage until the overvoltage condition subsides. SUMMARY OF THE INVENTION The subject invention has for its foundation a switch-type power converter/battery charger including a switch consisting of one or more FET's operating in a variable duty cycle mode. An integrated circuit controller such as the Unitrode UC 3846 is used with appropriate feedback and a rectifier and LC filter in the output stage to operate the switch to produce a regulated dc output. The subject converter in a typical commercial embodiment includes a rectifier bridge so that the unit may be connected to a standard 60 cycle normal 115 volt ac line. This is typical of the line voltage made available by electric utility companies and/or commercial generators. The feedback system is used to cause the overall converter to operate in a current demand mode wherein the duty cycle of the switch is adjusted to maintain the desired output voltage. In the preferred embodiment described herein, the converter further comprises a transformer for stepping voltages within the converter circuit down to a level suitable for use in connection with dc load devices and the charging of conventional storage batteries. Most of the reference voltages in the converter are taken from the primary side of the transformer. In addition, the fan supply and fan control are on the primary side of the transformer. By supplying the fan from the primary side, an undesirable drop in fan speed under heavy load conditions is avoided. According to a first, more specific aspect of the present invention, a circuit is provided at or near the dc input of the converter; i.e., at or near the output of the ac-to-dc rectifier circuit, for providing a permanent indication of an abnormal over-voltage condition sufficient to cause circuit damage and likely to be the result of operator error. In general, the permanent over-voltage indicator comprises a circuit connected between the output of the ac-to-dc rectifier and ground and includes a device, such as a Zener diode, for establishing a very high breakdown voltage, and a device, such as a fuse, which permanently changes state in response to an over-current condition. The fuse and Zener diode are preferably chosen in the commercial embodiment to correspond to the conditions which might exist if the converter were accidentally connected to a 220 volt ac supply or to an unregulated or runaway generator. The permanent change of state in itself has no effect on converter operation, since it is not a shut down mechanism similar to that of the over-voltage protection feature. But it does provide the manufacturer or warrantor of the system with evidence that any damage occurring to the converter and/or its various circuit components was the result of an extreme over-voltage condition rather than system malfunction or component defects. The permanent input over-voltage indicator is preferably used in combination with an over-voltage shutdown circuit also connected to the output of the ac-to-dc rectifier. The location and overall purpose of the over-voltage shutdown circuit is generally as described in the '066 patent where it is referred to as an overvoltage “protection” circuit, but preferably uses an operational amplifier to establish the shutdown set point voltage in a way which is more precise than that available from the use of a Zener diode as described in the '066 patent. The output of the over-voltage shutdown circuit is connected to a shut down pin in the variable duty cycle controller so as to prevent the switch transistors from turning on (and off again) while the over-voltage condition persists. This protects the expensive FET's and other components in the switch from damage. The set point of the over-voltage shutdown circuit in the illustrated embodiment is lower than that associated with the permanent over-voltage indicator device described above and the two circuits work in a cooperative fashion; i.e., the over-voltage shutdown circuit effects a shut down function at a first over voltage level whereas the permanent over-voltage indicator circuit changes state at a substantially higher over-voltage level likely resulting from, for example, owner/user error or generator runaway. However, the trip point of the overvoltage indicator could be set below or equal to the overvoltage shutdown circuit if the circuit designer wishes to do so. Another aspect of the present invention in the foundation environment described above is a permanent reverse battery connection indicator circuit. This circuit detects a so-called “reverse” battery condition which results from the erroneous reverse polarity connection of the storage battery to the recreational vehicle electrical system after a period of disconnection for storage or service. Like the over-voltage indicator, the permanent reverse battery connection circuit includes a component which undergoes a permanent change of state when the battery is accidentally connected with the positive and negative terminals in reverse positions. Again, the permanent indicator does nothing to shut down or disable system operation, but simply provides an unequivocal indicator of owner/user error in the event a warranty claim is later made. The converter of the present invention, like the converter described in the '066 patent, uses a metal heat sink as part of the converter packaging structure and mounts certain components on or in contact with the heat sink. A thermistor sensor, preferably mounted on or in contact with the heat sink, is used to monitor converter temperature and provide an output signal which, also unlike the '066 patent converter, is simultaneously supplied to two control circuits. The first control circuit operates the fan in a variable speed mode. These modes of operation are believed to not only extend fan life, but also reduce an annoying quality of fan noise. The thermistor sensor also furnishes a temperature-related signal to a second circuit including a comparator or “op-amp” to shut down the variable duty cycle controller in the event of a high temperature condition which may exceed the capacity of the fan. Other aspects of the invention in the area of thermal control include a special mounting arrangement between the fan motor and the extrusion which provides the heat sink; i.e., a recess is machined into an end of the heat sink extrusion to provide an air gap between the extrusion and the fan motor so that the fan motor does not directly pick up heat from the extrusion. In addition, heavy wire leads are used in overlying relationship to the copper plating of a circuit board used to mount the elements of the circuit of FIG. 2 . The wire leads are soldered to the board in high current connector areas. Numerous advantages flow from these packaging modifications as will be hereinafter explained in greater detail. Still further aspects and advantages of the invention are described herein and will be best understood from a reading of the following specification which describes and illustrative embodiment in the form of an 80 amp power converter for use in recreational vehicles of the type using conventional storage batteries. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a switched power converter circuit according to the present invention; FIG. 2 is a schematic circuit diagram of an illustrative switched power converter circuit embodying the inventive features described above; FIG. 3 is a graph of temperature versus fan speed illustrating the operating curve of the fan according to the present invention; FIG. 4 is a graph of fan voltage versus fan speed for a typical fan; FIG. 5 shows various waveforms within the circuit of FIG. 17 ; FIG. 6 is a graph of output converter current versus temperature for a variety of fan speeds; FIG. 7 is a partial schematic diagram illustrating a temperature-responsive input circuit according to the present invention; FIG. 8 is a graph of V tempvar of FIG. 7 versus fan voltage showing the desired characteristic; FIG. 9 shows partial schematics of a fan connected to an operational amplifier; FIG. 10 shows a partial schematic of a fan connected to an open collector operational amplifier and a graph showing the resulting fan voltage curve with temperature changes; FIG. 11 shows the partial schematic of FIG. 10 with the addition of a gain amplifier and a graph showing the resulting fan voltage curve with temperature changes; FIG. 12 shows the partial schematic of FIG. 11 with the addition of circuit to shift the zero point of the fan voltage curve and a graph showing the resulting fan voltage curve with temperature changes; FIG. 13 shows the equivalent circuit to the circuit to shift the zero point of FIG. 12 ; FIG. 14 shows the equivalent circuit to the open collector operational amplifier of FIG. 12 ; FIG. 15 is a schematic of a first embodiment of the control circuit according to the present invention; FIG. 16 is a schematic of a second, alternative, embodiment of the control circuit according to the present invention; FIG. 17 illustrates the two output current paths generated by the secondary-output side of transformer T 1 ; FIG. 18 is a perspective view of a fully packaged power converter embodying the features described herein; FIG. 19 is a cross-section of an illustrative heat sink showing a spring clip to hold a diode in the switch circuit against the heat sink; FIG. 20 is an end elevational view of the power converter package of FIG. 18 ; FIG. 21 is an opposite end elevational view of the power converter package of FIG. 18 ; FIG. 22 is a top plan view of the switched power converter package of FIG. 18 ; FIG. 23 is a perspective view of a RV partially broken away to show the switched power converter according to the invention positioned therein; FIG. 24 is a perspective view of the heat sink of FIG. 19 showing a recess or relief in the fan mounting surface. FIG. 25 is a photograph of one side of the circuit board used to support the components in the circuit of FIG. 2 showing heavy wires connected from the center top of the transformer through the circuit board; and FIG. 26 is a photograph of the reverse side of the circuit board, with the image reversed to coincide with the orientation of the FIG. 25 photograph, showing the heavy wires from the transformer coming through the circuit board and soldered over the conductive traces leading to the negative output terminal. This photograph also shows additional heavy wires running from the fuses to the positive output terminal and also soldered to and in overlying relation to circuit board traces. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram of a circuit for a switched power converter embodying the features of the present invention. The block diagram includes an AC-to-DC rectifier circuit 10 , a switch circuit 12 , a transformer circuit 14 , a feedback circuit 16 , a controller 18 , an over-voltage shutdown circuit 20 , a permanent over-voltage indicator 22 , a permanent reverse battery indicator 24 , a thermistor circuit 26 , a variable speed fan 32 , fan control circuit 30 , an over-temperature shutdown circuit 28 , a current sensing feedback circuit 34 , a foldback circuit 42 , and an output rectifier and LC filter circuit 44 including the inductor L 2 referred to hereinafter. The AC-to-DC rectifier circuit 10 converts a 115 v AC line voltage into an unregulated and time-varying dc signal with an average in the 170 volt range. It should be noted that the converter 46 can be plugged into a 170 vdc source, if available. In this case the rectifier 10 performs no rectification functions. The unregulated DC signal then enters the switching circuit 12 where the on/off states and duty cycle of the switching circuit 12 is determined by the controller 18 and feedback circuits 34 and 16 . The switching circuit 12 includes two field effect transistors (FET's). The output of the switching circuit 12 is a regulated waveform containing unidirectional pulses. Current sensing feedback circuit 34 is connected to the output of the switching circuit 12 for the purpose of measuring the output current. The output of the current sensing circuit 34 is connected to controller 18 . Controller 18 adjusts the duty cycle of the FET's in the switching circuit 12 according to the current measured by the current sensing circuit 34 and the voltage measured by circuit 16 . Accordingly, duty cycle is controlled by two factors: voltage feedback via circuit 16 and current feedback via circuit 34 . Over-voltage shut-down circuit 20 is connected between the output of the AC-to-DC rectifier circuit 10 and a shut-down pin of the controller 18 for the purpose of shutting off the switching circuit 12 in the event the rectified input voltage at 40 exceeds a pre-determined threshold voltage such as 195 vdc. The permanent over-voltage indicator 22 is connected to the output of the AC-to-DC rectifier circuit 10 for the purpose of triggering a permanent indicator in the event the voltage at 40 exceeds a second, higher threshold voltage, such as 220 vdc. As noted above, the second threshold voltage will typically be higher than the first, but could be lower or equal to the first threshold voltage. The over-voltage shut-down circuit 20 will protect the costly transistor components of the switching circuit 12 from being destroyed by the excessive input voltage conditions. The permanent over-voltage indicator 22 will provide evidence to the manufacturer that an undesirably high AC input voltage had been connected to the converter, e.g., a 220 VAC line voltage. The threshold voltage triggering the over-voltage shut-down circuit 20 is typically lower than the threshold voltage triggering the permanent over-voltage indicator 22 , but can be higher or equal to the overvoltage indicator circuit trigger voltage. The regulated signal passes from the switching circuit 12 to the transformer circuit 14 . The transformer circuit 14 steps down the average of the unidirectional pulses to the level necessary for recreational vehicle use; e.g., ultimately to about 13.6 volts. The stepped down waveform is rectified and smoothed by circuit 44 before application to load devices. Feedback circuit 16 measures the voltage across the load. The output of the feedback circuit 16 is connected to controller 18 . Controller 18 then controls the on/off state and duty cycle of the switching circuit 12 based in part on the input received from the feedback circuit 16 . A permanent reverse battery indicator 24 is also connected across the DC load for the purpose of providing a physical record that the operator connected a battery in reverse polarity. Such reverse battery connections may cause damage to the switched power converter, and the manufacturer may have an interest in knowing whether the damage was caused by the reverse connection of the RV battery as opposed to a manufacturing defect. Thermistor circuit 26 senses the temperature of a heat sink 52 in the housing 70 , and provides a variable resistance based on temperature. Over-temperature shutdown circuit 28 receives a signal from the thermistor circuit 26 and, if a set-point is exceeded, sends a shutdown signal to the controller 18 . Controller 18 then terminates the operation of switching circuit 12 . The over-temperature shutdown circuit 28 will not permit the operation of the switching circuit 12 until the temperature sensed by the thermistor has fallen below the undesirable temperature limit. Hysteresis in the circuit makes the temperature at which operation is resumed lower than the shutdown temperature. Fan control circuit 30 receives a signal from thermistor circuit 26 . The fan control circuit 30 produces a variable output based on the input from the thermistor 26 . A variable speed fan 32 is connected to the variable output signal of the fan control circuit 30 , such that the fan 32 will vary in speed based on the input signal. Accordingly, the speed of the fan 32 increases in response to increases in sensed temperatures. A low fan speed minimizes the annoying effects of fan noise at low to moderate power levels. The power supply for the fan 32 comes from the primary side of transformer circuit 14 . This feature eliminates the tendency of the fan supply voltage to droop, with a corresponding fan speed reduction, under heavy load conditions. Having briefly described the overall block diagram of the switched power converter circuit, the schematic circuit of an illustrative, mechanical embodiment will be described in detail with reference to FIGS. 2 , 5 and 17 . The preferred values of all described electrical components are listed at the end of the detailed description. Input Circuit Input circuit 36 is connected to a conventional AC power supply through a cable having a conventional 3-prong connector. The 3-prong connector includes a ground conductor, a positive conductor, and a neutral conductor. The cable runs into the housing through an aperture 100 . The AC positive terminal is connected to AC positive input W 1 . The AC ground terminal is connected to AC ground W 2 identified by a “chassis ground” symbol. The AC neutral terminal is connected to AC neutral input W 3 . AC positive input W 1 is connected to thermistor RT 2 . Thermistor RT 2 is used as an inrush current protector for the purpose of protecting fully discharged capacitors from receiving a surge of current. Thermistor RT 2 initially (i.e. when cold) provides a high resistance but rapidly changes to a substantially lower resistance as the temperature increases, allowing an unrestricted AC signal to pass into the noise suppression circuit 38 . It should be noted that there is a primary ground, secondary ground and a “chassis” ground and that different symbols are used for these in FIG. 2 . Noise Suppression Circuit The noise suppression circuit 38 includes capacitors C 15 , C 16 , C 26 , C 1 , C 2 , C 3 , C 30 , C 29 , and C 31 , inductor beads L 5 , L 6 , L 7 , and L 8 , jumpers J 6 , J 7 , J 8 , J 9 , J 10 , and J 11 , and common mode choke (CMC) transformers T 3 , and T 2 . These electrical components provide electromagnetic interference noise suppression, and filtering to prevent noise from within the converter from traveling back into the ac supply line. Noise transfer suppression is also provided by capacitors C 15 , C 16 , and C 26 . One plate of C 15 is connected to thermistor RT 2 , and one plate of C 16 is connected to AC neutral input line W 3 . The other plates of capacitor C 15 , and C 16 are connected to chassis ground, i.e., the ground of input W 2 . Capacitor C 26 is connected in parallel to C 15 and C 16 , where one plate of capacitor C 26 is connected to thermistor RT 2 , and the other plate of capacitor C 26 is connected to AC neutral input line W 3 . Both plates of capacitor C 26 are connected through CMC transformer T 3 . Winding 2 - 1 of CMC transformer T 3 is connected to thermistor RT 2 , and winding 3 - 4 of CMC transformer T 3 is connected to AC neutral input line W 3 . The output of winding 2 - 1 is connected to the input side of fuse F 1 . Additional noise suppression is provided by capacitors C 1 , C 2 , and C 3 . One plate of capacitor C 1 is connected to the output side of fuse F 1 , and the remaining plate of capacitor C 1 is connected to winding 3 - 4 of CMC transformer T 3 . Capacitor C 1 is also connected to one plate of each of capacitors C 2 and C 3 . The remaining plates of capacitors C 2 and C 3 are connected to chassis ground. CMC transformer T 2 is connected in parallel to capacitors C 2 and C 3 . Winding 2 - 1 of CMC transformer T 2 is connected to the ungrounded plate of capacitor C 2 , and winding 3 - 4 of CMC transformer T 2 is connected to the ungrounded plate of capacitor C 3 . Jumpers J 6 , J 7 , J 8 , are connected in parallel to winding 2 - 1 of CMC transformer T 2 , and jumpers J 9 , J 10 , and J 11 are connected in parallel to winding 4 - 3 of CMC transformer T 2 . All jumpers provide the option of bypassing CMC transformer T 2 . Additional noise suppression is provided by capacitors C 30 , C 29 , and C 31 . The windings of CMC transformer T 2 are connected in parallel to capacitor C 30 . Capacitor C 30 is also connected to one plate of each of capacitors C 29 and C 31 . The remaining plates of capacitors C 29 and C 31 are connected to chassis ground. High frequency noise suppression is provided by inductor beads L 5 , L 6 , L 7 , and L 8 . L 6 and L 8 are fitted onto the bridge connection wires by causing the wires to pass through the center opening of each inductor bead core, wrap around the bead core, and then pass again through the bead core. The wires passing through L 6 and L 8 are then connected between T 2 and a diode bridge DB 1 forming the AC-to-DC rectifier 10 . The inductor beads L 5 and L 7 are similarly mounted on the wires coming out of the diode bridge DB 1 (see FIG. 2 ). AC-to-DC Rectifier The AC-to-DC rectifier 10 is composed of a diode bridge DB 1 , capacitors C 4 a , C 4 b , and C 4 c . The wires passing through L 6 and L 8 are connected to the input of diode bridge DB 1 . The wires passing through L 5 and L 7 are connected to the output of diode bridge DB 1 . Capacitors C 4 a , C 4 b , and C 4 c are connected in parallel between wires passing through inductor beads L 5 and L 7 . The wire passing through L 5 is connected to the positive plate of each capacitor C 4 a , C 4 b , and C 4 c , and the wire passing through L 7 is connected to the negative plate of each capacitor C 4 a , C 4 b , and C 4 c . The negative plates of capacitors C 4 a , C 4 b , and C 4 c are also connected to ground. Under optimal conditions capacitors C 4 a , C 4 b , and C 4 c are charged by the output of diode bridge DB 1 to a desired voltage of 170 volts. Capacitors C 4 a , C 4 b , and C 4 c provide an unregulated DC signal to unregulated DC terminal 40 . Permanent Over-Voltage Indicator The permanent over-voltage indicator 22 includes fuse Fx 1 and Zener diode D 23 connected in series between the output 40 of rectifier bridge DB 1 and ground. The permanent over-voltage indicator 22 receives the voltage developed across capacitors C 4 a , C 4 b , and C 4 c , and causes the fuse to change state if the voltage across the capacitors reaches an undesirably high level. The cathode of Zener diode D 23 is connected to the output of fuse Fx 1 and the anode of Zener diode D 23 is connected to ground. It will be noted in FIG. 2 there are three different ground symbols. One is chassis ground, connected between C 2 and C 3 for instance. Another is primary circuit ground, connected to pin 12 of U 1 for instance. And lastly there is a secondary circuit ground, connected to the output P 1 terminal for instance. Each of these three ground symbols refer to separate voltage reference points and are isolated from each other. It will be further noted that the primary ground symbol is subdivided into an S, S 2 and P ground. The explanation is: S is the signal ground S 2 is the current sensing circuit ground P is the power ground In practice, these grounds are separate except at one point in circuit board layout to avoid parasitic noise cross talk. Nevertheless, physically they are the same since they are connected by copper traces and wires. The same is the case for the S and P shown with secondary ground symbol. The purpose of the permanent over-voltage indicator 22 is to provide a permanent indication of receiving an undesirably high input voltage greater than that which triggers the over voltage shut down circuit 20 . If the permanent over-voltage indicator 22 changes state, it will be because the converter input receives an excessive voltage, caused, for example, by a 220 vac supply or runaway generator. If enough voltage is applied to Zener diode D 23 it will fail short creating a direct connection between fuse Fx 1 and ground. This short failure of D 23 causes Fx 1 to permanently change state, i.e., blow out to create an open circuit. The preferred voltage limit of the permanent over-voltage indicator 22 is normally 220 volts dc. It will be noted that because the indicator circuit 22 is a shunt, failing the diode and blowing the fuse Fx 1 does not disable the converter. The term “permanent” is used herein to mean device which does not reset by itself; i.e., it must be replaced to operate a second time. Since tripping the indicator does not shut down the converter, the owner has no reason to replace it and typically will not be aware of its presence. Therefore, it remains in the converter until the converter is returned for service or a warranty claim. For the majority of converters, this never happens. However, for the small percentage of converters returned for a warranty claim, the indicator helps the manufacturer evaluate the likelihood that circuit failures are the result of excessive input voltage other than manufacturing or material defect. If a converter is returned for service and the indicator fuse Fx 1 is failed, it will be replaced along with any other failed components and may, for example, signal the need to provide the owner with a cautionary message regarding the quality of the supply voltage source being used. Over-Temperature Shut-Down Circuit The over-temperature shutdown circuit 28 measures the heat sink temperature in the switched power converter and triggers a shutdown of the switching circuit 12 upon receiving an undesirably high temperature. The over-temperature shutdown circuit 28 includes Schottky diode D 3 , resistors R 8 , RN 1 B, R 7 , and RN 1 A, operational amplifier U 3 A, and thermistor RT 1 . Thermistor RT 1 changes in resistance based on sensed temperature. Preferably thermistor RT 1 is a negative-temperature-coefficient device and is mounted on or in contact with the converter heat sink 52 in the manner shown in FIG. 19 ; i.e., a spring clip holds the sensor against a surface of the casting which makes up the sink 52 . Because the FET's in the switch 12 are also mounted in contact with the sink 52 , heavier load conditions cause the temperature of the sink 52 to rise. If turning the fan 32 on stabilizes the temperature, no further remedy is needed. It should be noted that the thermistor RT 1 does not have to be mounted on the heat sink, but can be mounted to measure, for example, air temperature or the temperature of some component such as the transformer 14 or the output inductor in circuit 44 . The illustrated arrangement is, however, preferred. Operational amplifier U 3 A is used as a comparator for the purpose of triggering shutdown pin (pin 16 ) of controller 18 in the event that the internal temperature of the switched power converter exceeds a set-point temperature. Once shutdown pin (pin 16 ) of controller 18 is triggered the operation of switching circuit 12 is terminated. Operational amplifier U 3 A includes the following connections: pin 1 is the output, pin 2 is the negative input, pin 3 is the positive input, pin 4 is connected to a 5 volt reference voltage 5 REF, and pin 11 is connected to ground. Pin 2 is connected to a temperature based variable voltage coming from a voltage divider circuit comprised of resistor RN 1 A and thermistor RT 1 . Pin 3 is connected to a reference voltage through a voltage divider circuit using resistors R 8 , R 7 , and RN 1 B. Pin 1 is connected to resistor R 8 , and Schottky diode D 3 leading to shutdown pin (pin 16 ) of controller 18 . The output of operational amplifier U 3 A will remain at a low (ideally zero) voltage and will not trigger shutdown pin 16 of controller 18 as long as pin 3 input does not exceed the pin 2 input. When the internal temperature is sufficiently high, the voltage on pin 3 will exceed the voltage on pin 2 and the output of pin 1 will go high and trigger a shutdown. The over-temperature shutdown circuit 28 will operate as follows under a cold temperature condition (i.e. a temperature condition where a thermal shutdown is not required). Resistor RN 1 A and thermistor RT 1 form a voltage divider circuit. Resistor RN 1 A is connected to a 5 volt reference 5 REF and thermistor RT 1 is connected to ground. Thus, pin 2 receives the voltage between resistor RN 1 A and thermistor RT 1 . Accordingly, the voltage applied to pin 2 will vary depending on the temperature of the heat sink 52 . The value of resistor RN 1 A is 16.2K ohms, and the value of thermistor RT 1 is 100K ohms of 25° C. Thus, when the switched power converter is initially turned on and the temperature is cold the value of thermistor RT 1 will be about 100K ohms. At cold startup the voltage applied to the pin 2 of operational amplifier is roughly 4.3 volts. Further, at a cold (i.e. non thermal shutdown) temperature pin 1 will be near 0 volts because the voltage at pin 2 is higher than the voltage at pin 3 . When the voltage at pin 1 is near 0 volts, resistor R 8 is parallel with resistor R 7 . In the illustrative embodiment, the values of resistors R 8 , R 7 and RN 1 B are 499K, 32.4K, and 47.5K ohms respectively. Because resistors R 8 and R 7 are in parallel, their equivalent resistance at 25° C. is 30.4K ohms. This resistance of 30.4K ohms will be called R coldtemp . Accordingly, the voltage at pin 3 will be the measured voltage between resistor RN 1 B and R coldtemp . Using a voltage divider, the voltage applied to pin 3 at a cold temperature is 1.925 volts. This voltage will be called V coldtemp . Accordingly, at a cold temperature the voltage at pin 3 will be V coldtemp which is 1.925 volts. If the internal temperature significantly increases, the resistance of thermistor RT 1 will decrease and the voltage applied to pin 2 will fall below the voltage applied to pin 3 , the output of pin 1 will become positive, and the switched power converter will experience a thermal shutdown. The over-temperature shutdown circuit 28 will operate as follows under a thermal shutdown condition (i.e. a temperature condition where a over-temperature shutdown is required). A shut down temperature is never reached if the load on the converter is within normal specifications because the fan 32 will provide sufficient cooling. If the load is very heavy and/or the operator has covered the converter 46 with blankets or the like, a shut down temperature may be reached. If this happens, the voltage applied to pin 1 will be approximately 5 volts. When pin 1 reaches 5 volts, resistors RN 1 B and R 8 will be in parallel (as opposed to resistor R 7 being in parallel with resistor R 8 at a cold temperature). The equivalent resistance of resistors RN 1 B and R 8 in parallel is 43.37K ohms. This resistance will be called R hottemp . Accordingly, the voltage at pin 3 will be the measured voltage between resistor R 7 and R hottemp . Using a voltage divider the voltage applied to pin 3 at a cold temperature is 2.138 volts. This voltage will be called V hottemp . Accordingly, in order for the switching circuit 12 to begin operation the voltage on pin 2 must rise above V hottemp (rather than V coldtemp ). This hysteresis caused by resistor R 8 is important so that the switching circuit 12 will not be enabled until the internal temperature falls significantly below the temperature at which the thermal shutdown was triggered. Over-Voltage Shutdown Circuit The over-voltage shutdown circuit 20 measures the voltage of capacitors C 4 a , C 4 b , and C 4 c , and will shutdown the switching circuit 12 in the event of an over-voltage condition at point 40 . The over-voltage circuit 20 includes resistors R 38 , R 39 , R 40 , R 7 , and RN 1 B, operational amplifier U 3 B, and Schottky diode D 27 . The output of over-voltage shut down circuit 20 is connected to shutdown pin 16 of controller 18 , such that a high signal will terminate the operation of switch 12 . The over-voltage shut-down circuit 20 assures that transistors Q 2 a and Q 2 b are not damaged in the event of an undesirably high voltage at the output of the ac-to-dc converter; i.e., at point 40 . As discussed above, there are a number of factors which may cause high voltage conditions to exist. Lightning strikes or transients from other loads on the supply line, unregulated generators, runaway generators and the like may all cause over-voltage conditions. Transistors Q 2 a and Q 2 b are rated at 500 volts. Because of the properties of transformer T 1 , transistor elements Q 2 a and Q 2 b will experience a voltage twice that imposed on capacitors C 4 a , C 4 b , and C 4 c . Accordingly, when capacitors C 4 a , C 4 b , and C 4 c are at 250 volts, the transistor elements Q 2 a and Q 2 b will experience 500 volts. Accordingly, if the voltage of capacitors C 4 a , C 4 b , and C 4 c exceeds 250 volts transistors Q 2 a and Q 2 b may be damaged. Operational amplifier U 3 B includes the following connections: pin 7 is the output, pin 6 is the negative input, pin 5 is the positive input, pin 4 is connected to a 5 volt reference voltage 5 REF, and pin 11 is connected to ground. Pin 5 is connected to a voltage divider circuit comprised of resistors R 38 , R 39 , and R 40 . The voltage applied to pin 5 will vary depending on the line voltage of capacitors C 4 a , C 4 b , and C 4 c . Pin 6 is connected to a reference voltage through a voltage divider circuit comprised of resistors R 8 , R 7 and RN 1 B. Pin 7 is connected to resistor R 40 , and schottky diode D 27 leading to shutdown pin 16 of controller 18 . The output of operational amplifier U 3 B will remain as a low, ideally zero, voltage and will not trigger shutdown via pin 16 of controller 18 as long as pin 5 input does not exceed pin 6 input. When the line voltage of capacitors C 4 a , C 4 b , and C 4 c is sufficiently high, the voltage on pin 5 will exceed the voltage on pin 6 and the output of pin 7 will trigger a shutdown. The over-voltage shut-down circuit 20 will operate as follows under a normal voltage condition (i.e. a voltage condition that does not require an over-voltage shutdown). Resistors RN 1 B and R 7 form a voltage divider circuit, where resistor RN 1 B is connected to a 5 volt reference 5 REF and resistor R 7 is connected to ground. Accordingly, pin 6 receives the voltage between resistor RN 1 B and R 7 . Remember, that the voltage applied between resistors RN 1 B and R 7 will vary depending upon the operation of the over-temperature circuit 28 (i.e. when the temperature is cold resistor R 8 is in parallel with resistor R 7 , and when a thermal shutdown temperature is achieved resistor R 8 is in parallel with resistor RB 1 B). Accordingly, the voltage applied to pin 6 will vary depending on whether or not a thermal shutdown temperature is present. However, once a thermal shutdown has been triggered by over-temperature shut-down circuit 28 the operation of the over-voltage circuit 20 is irrelevant. Thus, for this explanation it will be assumed that the temperature is below shutdown level and resistor R 8 is in parallel with resistor R 7 . In the illustrated embodiment, the values of resistors R 8 , R 7 and RN 1 B are 499K, 32.4K, and 47.5K ohms respectively. Remembering that at a low temperature resistors R 8 and R 7 are in parallel, their equivalent resistance is 30.4K ohms. This resistance of 30.4K ohms will be called R coldtemp . Accordingly, the voltage at pin 6 will be the measured voltage between resistor RN 1 B and R coldtemp . Using a voltage divider the voltage applied to pin 6 at a cold temperature is 1.925 volts. This voltage will be called V shutdownref . In illustrative embodiment, the value of resistors R 38 , R 39 , and R 40 is 84.5K, 866, and 97.6K ohms, respectively. Prior to an over-voltage shutdown, pin 7 will remain at a low, ideally zero, voltage, causing resistor R 40 to be in parallel with resistor R 39 . The equivalent resistance of resistors R 39 and R 40 in parallel is 858.4 ohms. This resistance of 858.4 ohms will be called R normalvoltage . Pin 5 receives the voltage between the voltage divider circuit created by resistors R 38 and R normalvoltage . Accordingly, the unregulated DC terminal 40 voltage must exceed 195 volts for the voltage at pin 5 to exceed V shutdownref (e.g. if unregulated DC terminal 40 carries a voltage of 195 volts, pin 5 will be at approximately 1.961 volts which sufficiently exceeds the 1.952 volts applied to pin 6 ). Thus, when the unregulated DC terminal 40 reaches a voltage of 195 volts the output of pin 7 will become positive causing controller 18 to shutdown the switching circuit 12 . Because capacitor voltage is approximately 1.4 times AC line voltage, the illustrative embodiment of the over-voltage shutdown circuit 20 will shut down the DC output if the AC input voltage exceeds 140 volts (i.e. the voltage of capacitors C 4 a , C 4 b , C 4 c exceeds 195 volts). Remember that the preferred embodiment of the permanent over-voltage indicator 22 will be triggered at about 220 volts. Accordingly, the output of the switched power converter will be terminated by the over-voltage shut down circuit 20 at a lower over-voltage condition than that which changes the state of the fuse Fx 1 in the permanent over-voltage indicator 22 . The over-voltage shutdown circuit 20 operates as follows under an over-voltage shutdown condition (i.e. the AC input voltage exceeds 140 volts). When a over-voltage shutdown condition is reached, the voltage applied to pin 7 is approximately 5 volts. When pin 7 reaches 5 volts, resistor R 40 is no longer in parallel with resistor R 39 , but will be used for a hysteresis effect. For example, when pin 7 is positive (i.e. over-voltage condition) resistor R 40 will provide feedback into pin 5 , which will in turn increase the voltage at pin 5 . Accordingly, once operational amplifier U 3 B triggers a shut down, the voltage at terminal 40 must be significantly lower than the 195 volts which triggered the initial shut down because resistor R 40 has temporarily increased the voltage measured by pin 5 . The purpose of the resistor R 40 hysteresis is to prevent the controller 18 from operating the switching circuit 12 until the voltage at terminal 40 has significantly fell below 195 volts. Fan Control Circuit The fan control circuit 30 includes resistors RN 1 A, R 4 , RN 1 C, R 2 a , R 1 , and R 20 , thermistor RT 1 , operational amplifier U 3 D, transistor Q 1 , capacitor C 5 , and Schottky Diode D 1 a . FIGS. 2-16 are used to describe the operation of the fan control circuit 30 and the fan 32 . In this embodiment, the fan 32 is powered by a dc motor which varies in speed as a function of voltage amplitude, i.e., it is the control circuit which produces the variable speed characteristic. The fan control circuit 30 commands the fan 32 to come on at an initial (lowest) temperature. The speed of the fan 32 increases with temperature and will maximize at some point prior to the switched power converter being at full load. The fan control circuit is also described in the aforementioned provisional application, attorney docket no. PDY-106-A, the content of which is incorporated herein by reference. An operating curve of the fan 32 using the fan control circuit 30 is shown in FIG. 3 . (The slope is not necessarily linear as discussed in more detail herein.) The fan control circuit 30 will cause the fan 32 to come on at low speed when temperatures are over the set point by only a small amount. The relationship between the voltage applied to the fan and the fan speed is shown in FIG. 4 . Due to static friction the fan 32 does not start moving until a certain voltage is reached. Specifically, and as illustrated in FIG. 4 , the fan blades will not move until the voltage at point 2 is reached. Compared to the thermal time constants, it more or less instantaneously starts moving, jumping to point 3 (initial turn on point). As the voltage increases, it moves to point 4 , where the fan 32 is operating at maximum speed. On the way down, the variable voltage controlled fan 32 follows from point 4 (maximum operation) to point 3 (initial turn on point) to point 1 (shut off). FIG. 6 illustrates in principle how the fan control circuit 30 works. Temperatures T H and T L are the temperatures at which the fan 32 is ideally full on and full off, respectively. More accurately, T H (line C) is the temperature at which full fan voltage is applied, and T L (line D) is the temperature at which no voltage is applied to the fan 32 . Currents below point 14 have steady-state operating points on the “fan off” line (line B). currents above point 15 have steady-state operating points on the “fan full on” line (line A). Therefore, points 14 and 15 must be the beginning and end of the line of operating points when operating at currents where the variable voltage controlled fan 32 is in an intermediate state between full on and full off. Although a straight line (line E) is shown connecting these two points, the relationship is not necessarily a linear one. It is clearly, however, a strictly increasing (positive slope) function. FIG. 6 illustrates the ideal case. Assume the switched power converter starts cold at current operating point I OP2 , point 1 . The switched power converter will warm up and at point 2 , T L , the fan 32 will start to turn slowly. The heat sink 52 continues to warm up until it reaches its steady-state operating point, point 4 . Similarly, for current operating point I OP1 , the switched power converter will start at point 18 , the fan 32 will come on at point 6 and settle into a steady speed at point 7 . Turning to FIG. 4 , the operating characteristics of fan 32 are explained. Assume that T L1 corresponds to point 1 on FIG. 4 and that T L2 corresponds to point 2 on FIG. 4 (same as point 3 ). Thus, returning to FIG. 6 , line G describes an actual fan 32 . Again, this relationship is not necessarily a linear one as shown, but it is a positive slope function. Starting cold with operating current I OP2 , the temperature increases. At point 2 (T L ), voltage starts being applied to the variable voltage controlled fan 32 , but it is not yet moving. At point 3 (T L2 ) the fan 32 begins to rotate. The switched power converter continues to heat up and eventually settles at point 5 (along line G). For I OP1 , the switched power converter would start cold at point 18 and heat up to point 6 (T L ). At point 6 , voltage begins to be applied to the fan 32 . The switched power converter will continue to heat up until point 9 (T L2 ), where the fan 32 begins moving. The fan 32 will now be moving faster than it needs to, the switched power converter will cool and eventually settle into a steady state speed at point 8 (along line G). In both cases, the fan 32 , once started, continues to rotate. There is no discontinuance of operation. Notice further that variable voltage controlled fan 32 speeds are slower (and less noisy) for all current levels up to point 15 (T H ). Also notice the minimum current to turn the fan 32 on corresponds to point 17 (T L2 ), but if already on, it will stay on to a lower current, corresponding to point 16 (T L1 ). A description of the fan control circuit 30 is illustrated in FIGS. 2 , and 7 - 16 . The preferred embodiment of the fan control circuit includes resistors RN 1 A, R 4 , RN 1 C, R 1 , and R 2 a , thermistor RT 1 , transistor Q 1 , and operational amplifier U 3 D. Operational amplifier U 3 D includes the following connections: pin 14 is the output, pin 12 is the positive input, pin 13 is the negative input, pin 11 is connected to ground, and pin 4 is connected to a 5 volt reference voltage 5 REF. As illustrated in FIGS. 2 , and 7 , thermistor RT 1 is used as a temperature sensor for the fan control circuit 30 as well as the over-temperature shutdown circuit 28 . Thermistor RT 1 is connected to ground as well as resistor RN 1 A which also connected to a 5 volt reference 5 REF. Thermistor RT 1 and resistor RN 1 A are used to create a voltage divider circuit where V tempvar is the output of the voltage divider circuit. V tempvar is connected to pin 13 of operational amplifier U 3 D. Preferably RT 1 is a negative-temperature-coefficient thermistor. As the internal temperature increases, V tempvar decreases. For the remainder of the fan control circuit 30 , a profile of a desirable fan voltage versus V tempvar is shown in FIG. 8 . Because the components used in switched power converter (i.e. operational amplifier U 3 D) are powered by 5 volts, whereas the fan 32 requires a nominal 12 volts, a direct connection of an operational amplifier such as that shown in FIG. 9 will not work. Simply stated an operational amplifier such as operational amplifier U 3 D cannot supply sufficient current or voltage to the fan 32 . Neither will transistor emitter follower-type circuits work because of voltage limitations. An open collector operational amplifier would work in a circuit such as that shown in FIG. 10 , and a simple gain amplifier would almost provide the desired profile as shown in FIG. 11 . Shifting the “zero” point will get the desired profile as shown in FIG. 12 . Specifically, a Thevenin resistance and voltage coupled to the negative input of the operational amplifier would shift the zero point of the fan control. FIG. 13 illustrates an equivalent of the Thevenin resistance and voltage, and the open collector operational amplifier is shown equivalently in FIG. 14 . Using a conventional operational amplifier having an output connected to resistor R 1 and transistor Q 1 will result in a complete fan control circuit according to FIG. 15 . In almost all cases, the fan 32 will be quiet, and only under extended high load or high ambient temperature condition will the switched power converter warm up enough to cause the fan 32 to be heard. Because the circuit in FIG. 15 has a linear range between full on and full off, significant power will be dissipated in transistor Q 1 at intermediate fan speeds. An alternative is to modify the linear circuit to act as a duty cycle control circuit as shown in FIG. 16 . With duty cycle control, transistor Q 1 will be either full on or full off (zero voltage or zero current), but the duty cycle will vary to control the speed of the fan. In FIG. 16 , resistor R 3 adds hysteresis and causes operational amplifier U 3 D to behave as a comparator. As the switched power converter warms up, transistor Q 1 is off until it reaches a “low” temperature. The fan control circuit 30 then breaks into oscillation with low “on” duty cycle on transistor Q 1 . As the switched power converter continues to warm, the duty cycle gets larger. When an upper temperature is reached, the oscillation stops, and transistor Q 1 is always on and stays on as the temperature increases further. The fan control circuit 32 as shown in FIG. 2 includes resistors RN 1 C and R 4 acting as a voltage divider circuit connected to pin 12 of operational amplifier U 3 D. Resistor RN 1 C is connected to 5 volt reference 5 REF and resistor R 4 is connected to ground. The preferred value of resistor RN 1 C is 9.53K ohms, and the preferred value of resistor R 4 is 22.6K ohms. More exactly, the currents flowing through R 2 a will also contribute to voltage at pin 12 . Analysis yields VP ⁢ ⁢ 1 ⁢ N ⁢ ⁢ 12 = + 5 ⁢ ⁢ VREF RNIC + VQ ⁢ ⁢ 1 ⁢ ⁢ C R ⁢ ⁢ 2 ⁢ a 1 R ⁢ ⁢ 2 ⁢ a + 1 RNIC + 1 R 4 where R 2 a has the preferred value of 453K and VQ 1 C is the collector voltage of Q 1 . When Q 1 is off and no current flows through the fan, VQ 1 C can be as high as the voltage in C 5 , which can vary with line voltage. Using a nominal value of 15 volts for the voltage on C 5 yields pin 12 voltages; VPIN 12 =3.4657 for VQ 1 c =0 volts VPIN 12 =3.6844 for VQ 1 c =15 volts Thus VPIN 12 can more exactly have a range of voltages between 3.4657 and 3.6844 depending on the voltage at the collector of Q 1 . At pin 13 of operational amplifier U 3 D, resistor RN 1 A and thermistor RT 1 act as a voltage divider circuit. The preferred value of resistor RN 1 A is 16.2K ohms, and the preferred value of thermistor RT 1 is 100K ohms at a cold start up temperature (25° C.). Accordingly, the initial voltage applied to pin 13 at a cold temperature is approximately 4.3 volts, which will be called V tempvar . At the initial startup of the switched power converter 46 , V tempvar is greater than 3.68 v. Thus the output of operational amplifier U 3 D is near zero causing transistor Q 1 to be off and the fan 32 is not running. As the temperature increases, the resistance of thermistor RT 1 will decrease causing the value of V tempvar to drop from the initial 4.3 volts. Eventually the temperature will increase such that the value of V tempvar will fall slightly below 3.68 volts. When this occurs the circuit including operational amplifier U 3 D will enter the linear region. There will be a slight fan voltage but it will probably remain in the stalled condition. If the temperature continues to increase the value of V tempvar will fall significantly below 3.68 v but above 3.46 v and operational amplifier U 3 D causes the fan to enter the mid speed range. As V tempvar falls further, op-amp U 3 D turns transistor Q 1 full on and the fan 32 reaches full speed. The fan control circuit 30 provides the variable voltage to control the speed of the fan 32 . The transformer circuit 14 provides steady power to the power input of the fan 32 . The power input for the fan 32 is connected to pin 3 of transformer T 1 , through Schottky diode D 1 a and resistor R 20 . Pin 7 of transformer T 1 is connected to ground, completing the power input circuit for the fan 32 . Resistor R 20 is used for the purpose of preventing the voltage applied to the fan 32 from exceeding specifications. One plate of capacitor C 5 is connected to ground and the other plate is connected between resistor R 20 and Schottky diode D 1 a for the purpose of providing a steady voltage to resistor R 20 . Capacitor C 5 is charged by transformer T 1 and carries enough voltage to power the fan 32 . Schottky diode D 1 a prevents capacitor C 5 from discharging into pin 3 of transformer T 1 . Because the power input to the fan 32 is connected to the primary side of the transformer circuit 14 , the fan control circuit 30 as well as the variable voltage controlled fan 32 will remain operational even when the output is heavily loaded or short circuited. Simply stated, this feature will permit the cooling system of the switched power converter to continue to operate in the event of an over-loaded output. Appropriately, the occurrence of this condition is when the operation of the fan 30 is most vital. Transformer Circuit Transformer circuit 14 is primarily inclusive of transformer T 1 . Pin 4 of transformer T 1 is the positive input line. Pin 4 is connected to unregulated DC terminal 40 , where the DC line voltage is approximately 170 volts. Pins 5 and 6 of transformer T 1 are connected to the switching circuit 12 . The switching circuit 12 provides a switching current to the primary-input side of transformer T 1 . For example, switching circuit 12 , which is controlled by controller 18 , allows current to flow between pins 4 and 5 , and between pins 4 and 6 . However, the current between pins 4 and 5 , and pins 4 and 6 will never flow simultaneously, but will alternate according to controller 18 . Operation is described below with reference to FIG. 17 . Switching Circuit As illustrated by FIGS. 2 and 17 , the preferred embodiment of the switching circuit 12 contains two transistors Q 2 a and Q 2 b . When transistor Q 2 a is turned on current I 1 will flow from pin 4 of transformer T 1 to pin 6 . Alternatively when transistor Q 2 b is turned on current I 2 will flow from pin 4 of transformer T 1 to pin 5 . When transistor Q 2 a is on transistor Q 2 b will be off, and when transistor Q 2 b is on, Q 2 a will be turned off. The primary-input side of transformer T 1 is utilized in such a fashion so that the transistors within the switching circuit 12 may operate at up to a maximum 50% duty cycle, meaning that transistors Q 2 a and Q 2 b are never on more than 50% of the time. As further illustrated in FIGS. 2 and 17 , the secondary-output side of transformer T 1 includes pins 2 , 8 , and 1 . When current I 2 flows between pins 4 and 5 of transformer T 1 , current I 4 will correspondingly flow between pins 8 and 2 . Alternatively, when current I 1 flows between pins 4 and 6 of the primary-input side of transformer T 1 , current I 3 will correspondingly flow between pins 8 and 1 of the secondary-output side. The switching circuit 12 further includes R 37 , R 23 a , R 23 b and C 24 (shown only in FIG. 2 ). Transistors Q 2 a and Q 2 b provide two current loops. Transistor Q 2 a is connected to pin 6 on the primary side of transformer T 1 , and transistor Q 2 b is connected to pin 5 on the primary side of transformer T 1 . Controller 18 controls the on/off state of transistors Q 2 a and Q 2 b . When transistor Q 2 a is turned on, Q 2 b is off. Current I 1 flows between pins 4 and 6 of transformer T 1 ; alternatively, when transistor Q 2 b is turned on, Q 2 a is off and current I 2 flows between pins 4 and 5 of transformer T 1 . The gate of transistor Q 2 a is connected to resistor R 23 a which is connected to AOUT (pin 11 ) on controller 18 . The gate of transistor Q 2 b is connected to resistor R 23 b which is connected to BOUT (pin 14 ) on controller 18 . When controller 18 applies a voltage to the gate of transistor Q 2 a , transistor Q 2 a turns on and allow current I 1 to flow from pin 4 of transformer T 1 , through pin 6 , and then to ground through the drain and source of transistor Q 2 a . Alternatively, when controller 18 applies a voltage to the gate of transistor Q 2 b , transistor Q 2 b will turn on and allow current I 2 to flow from pin 4 of transformer T 1 , through pin 5 and to ground through the drain and source of transistor Q 2 b. Resistor R 37 and capacitor C 24 are connected in series between the drain of transistors Q 2 a and Q 2 b for the purpose of snubbing the transient drain voltage when transistors Q 2 a and Q 2 b are switching. Controller Controller 18 is used for controlling the output of the switching circuit 12 by controlling the duty cycles of switching transistors Q 2 a and Q 2 b . Controller 18 receives input from the current sensing circuit 34 , over-voltage shut-down circuit 20 , over-temperature shut-down circuit 28 , feedback circuit 16 , and foldback circuit 42 . As discussed previously, AOUT (pin 11 ) and BOUT (pin 14 ) are connected to transistors Q 2 a and Q 2 b respectively for the purpose of controlling the duty cycle and switching current of the switching circuit 12 . SHDN (pin 16 ) is connected to both the output of the over-voltage shutdown circuit 20 and the over-temperature shutdown circuit 28 for the purpose of terminating the operation of the switching circuit 12 . If SHDN (pin 16 ) receives a sufficient voltage AOUT (pin 11 ) and BOUT (pin 14 ) will turn off transistors Q 2 a and Q 2 b , which will terminate the output across the DC load. CS+ and CS− are connections to operational amplifier CS, which is internal to controller 18 . The output of operational amplifier CS corresponds to the instantaneous voltage output of current sensing circuit 34 . CS+ (pin 4 ) is connected to the output of the current sensing circuit 34 , which measures the current through transistors Q 2 a and Q 2 b. EA+, EA−, and COMP are connections on operational amplifier EA, which is internal to controller 18 . The output of operational amplifier EA is compared to the output of operational amplifier CS. EA+ (pin 5 ), is connected to the output of the feedback circuit 16 . EA− (pin 6 ) is connected to COMP (pin 7 ), acting as a voltage follower on operational amplifier EA. Accordingly, the output of operational amplifier EA will be the same as the voltage applied to EA+ (pin 5 ). If the instantaneous output of operational amplifier CS exceeds the output of operational amplifier EA AOUT (pin 11 ) and BOUT (pin 14 ) transistors Q 2 a and Q 2 b are turned off. If the current generated by transistors Q 2 a and Q 2 b exceeds the limit set by feedback circuit 16 , controller 18 will temporarily terminate the gate drives to Q 2 and Q 2 b . This comparison/control function occurs on a cycle-by-cycle basis. CLADJ (pin 1 ) is used to further limit the current output of the switching circuit 12 . The voltage applied to CLADJ (pin 1 ) limits the maximum current output of the switched power converter. As the voltage applied to CLADJ (pin 1 ) decreases so does the maximum current output of the switched power converter. CLADJ (pin 1 ) is connected to the output of the foldback circuit 42 , where the foldback circuit will cause the current limit to decrease (i.e. reduce the voltage applied to CLADJ) in a near short circuit situation. CLADJ (pin 1 ) is also connected between resistors R 14 and R 15 which act as a voltage divider circuit. Resistor R 14 is connected to 5 volt reference 5 REF and is in series with resistor R 15 . Resistor R 15 is also connected to ground. VREF (pin 2 ) provides a 5.1 volt reference voltage which supplies power to various electrical components within the switched power converter. The output of VREF is identified as 5 volt reference 5 REF. VIN (pin 15 ) is connected to a power supply for the purpose of providing power to controller 18 . VIN (pin 15 ) is connected to Zener diode D 9 and capacitor C 10 which provide approximately 15 volts to controller 18 . Zener diode D 9 and capacitor C 10 receive voltage from unregulated DC terminal 40 through resistors R 24 a and R 24 b. VC (pin 13 ) is the power supply for the sales of transistors Q 2 a and Q 2 b through AOUT (pin 11 ) and BOUT (pin 14 ), respectively. VC (pin 13 ) is connected to VIN (pin 15 ) through resistor R 16 . Resistor R 16 is used to limit the current entering VC (pin 13 ). Schottky diodes D 16 a , D 15 a , D 15 b and D 16 b are used to prevent the voltage on AOUT (pin 11 ) and BOUT (pin 14 ) from exceeding VIN or from dropping below GND. GND (pin 12 ) is connected to ground. Capacitor C 25 is connected to CT (pin 8 ) and resistor R 13 is connected to RT (pin 9 ) for setting the frequency and maximum duty cycle of controller 18 . Capacitor C 25 and resistor R 13 are also connected to ground. SYNC (pin 10 ) is not utilized. Foldback Circuit As briefly mentioned, foldback circuit 42 provides feedback to controller 18 for the purpose of reducing the duty cycle of transistors Q 2 a and Q 2 b under near short circuit conditions rather than allowing the output current across the DC load to increase out of control. Foldback circuit 42 includes, diode D 4 , resistors R 19 a , R 19 b , R 17 , and R 18 , capacitor C 8 , and operational amplifier U 3 C. Operational amplifier U 3 C has the following connections: pin 8 is the output, pin 9 is the negative input, pin 10 is the positive input, pin 4 is connected to 5 volt reference 5 REF, and pin 11 is connected to ground. The foldback circuit 42 measures the duty cycle of transistors Q 2 a and Q 2 b . Pin 10 is connected to AOUT (pin 11 ) and BOUT (pin 14 ) on controller 18 through resistors R 19 a and R 19 b. Capacitor C 8 , which is connected between pin 10 and ground, as well as in series with resistors R 19 a and R 19 b is used for the purpose of averaging the duty cycle controlled gate voltages of transistors Q 2 a and Q 2 b . Resistor R 17 is connected between 5 volt reference 5 REF and pin 10 , and resistor R 18 is connected between pin 10 and ground for the purpose of creating a voltage divider circuit to reduce the voltage applied to pin 10 . Pin 9 is connected to pin 8 for the purpose of creating a voltage follower, such that the voltage at pin 8 will always equal the voltage applied to pin 10 . Pin 8 is also connected to the cathode of diode D 4 , and the anode of diode D 4 is connected to CLADJ (pin 1 ) of controller 18 . As the duty cycle of AOUT (pin 11 ) and BOUT (pin 14 ) increases, the voltage of capacitor C 8 increases as well as the voltage on pin 10 . Accordingly, the voltage on pin 8 will be higher than the voltage between resistors R 15 and R 14 . When this occurs, diode D 4 will be reverse biased and the voltage at CLADJ (pin 1 ) of controller 18 will not be affected. In this situation the current limit of CLADJ will neither decrease nor increase because foldback circuit 42 is not pulling current from CLADJ (pin 1 ). As the duty cycle of AOUT (pin 11 ) and BOUT (pin 14 ) decreases, the voltage of capacitor C 8 decreases as well as the voltage on pin 10 . Accordingly, the voltage on pin 8 will be lower than the voltage between resistors R 15 and R 14 . When this occurs, diode D 4 will be forward biased and the voltage at CLADJ (pin 1 ) of controller 18 will be pulled down. As the voltage applied to CLADJ (pin 1 ) decreases, the maximum current output of controller 18 will also decrease. Accordingly, in the event of a near short circuit at the DC load, the reduced current limitation of CLADJ will prohibit the current output from going unreasonably high and reduce the output current to less than its previous maximum rating. Voltage Feedback Circuit The feedback circuit 16 measures the voltage across the DC load and outputs a reference voltage to controller 18 . Controller 18 contains an internal voltage controller, for the purpose of providing a voltage controlled current source. Controller 18 will control the switching of transistors Q 2 a and Q 2 b accordingly. Feedback circuit 16 includes resistors R 28 , R 34 , R 32 , R 26 , R 25 , R 33 and R 30 , capacitors C 27 , C 22 , C 20 , and C 28 , and optical coupler U 2 which includes a LED, a photo-sensor and a 2.5 volt reference. When the DC load is increased, there is an immediate drop in voltage across the DC output terminals of the power converter. This drop in voltage requires an increase of output current in the output circuit 44 in order to meet the new load demands. Alternatively, when the DC load is decreased, there is an immediate increase in voltage. This increase in voltage requires a decrease in the output current of the output circuit 44 in order to compensate for the load reduction. For example, when the operator of the switched power converter brings an additional load on-line, the feedback circuit 16 first measures the voltage across the load and then scales the voltage down to a 2.5 volt range. Because a new load has been added the measured voltage will be below the 2.5 voltage range. Optical coupler U 2 will compare the measured voltage (scaled down) against a 2.5 volt reference. Because the measured voltage across the load will be below the 2.5 reference voltage, optical coupler U 2 will cause the LED to produce less light. When the LED produces less light the photo-sensor will cause the output of the feedback circuit to increase in voltage. The output of the photo-sensor is connected to EA+ (pin 5 ) on controller 18 . When the voltage input of EA+ (pin 5 ) increases, the voltage controller within controller 18 will temporarily increase the duty cycle of the switching circuit 12 . This in turn increases the load current to meet the new load demand (i.e. get the voltage across the DC load back up to 13.6 volts). Alternatively, when the operator of the switched power converter removes a load, the feedback circuit 16 measures the voltage across the load and then scales the voltage down to a 2.5 volt range. Because a load has been removed the measured voltage will be above the 2.5 voltage range. Opto-coupler U 2 will compare the measured voltage (scaled down) against a 2.5 volt reference. Now, because the measured voltage across the load will be above the 2.5 reference voltage, opto-coupler U 2 will cause the LED to produce additional light. When the LED produces additional light the output of the feedback circuit will decrease in voltage. The output of the photo-sensor is connected to EA+ (pin 5 ) on controller 18 . When the voltage input of EA+ (pin 5 ) decreases, the voltage controller within controller 18 will temporarily decrease the duty cycle of the switching circuit 12 . This in turn, decreases the load current to meet the reduced load demand (i.e. get the voltage across the DC load back down to 13.6 volts). Resistor R 25 limits current to opto-coupler U 2 . Resistor R 26 and R 28 are arranged as a voltage divider to provide a scaled output voltage in the vicinity of 2.5 volts. Capacitors C 20 , C 22 , C 27 , C 28 , R 34 , R 32 and R 33 are used for stability, do not affect the DC levels whatsoever as they carry no DC current. Resistor R 30 is used for providing an input voltage to EA+ (pin 5 ) of controller 18 based on the current output of opto-coupler U 2 . Current Sensing Circuit Current sensing circuit 34 is used to measure the current being drawn by transistors Q 2 a and Q 2 b and to send the measured current to CS+ (pin 4 ) of controller 18 . Controller 18 then compares this measured current to a reference level. The reference level is the output of feedback circuit 16 , which is connected to EA+ (pin 5 ) on controller 18 . Depending upon the measured current and the reference level, controller 18 will control the on/off state of transistors Q 2 a and Q 2 b. Current sensing circuit 34 includes transformer T 4 , diodes D 24 a , D 24 b , D 24 c , and D 24 d , resistors R 21 , R 21 a , R 21 b , R 21 c , R 21 d , and R 21 e , and capacitor C 9 . The drain of transistor Q 2 b is connected to pin 4 of transformer T 4 , and the drain of transistor Q 2 a is connected pin 6 of transformer T 4 . The output side of transformer T 4 (pins 1 and 2 ) is connected to a series of diodes and resistors and then to CS+ (pin 4 ) of controller 18 . Diodes D 24 a , D 24 b , D 24 c , and D 24 d make up a full wave rectifier bridge. Diodes D 24 c and D 24 b are connected in parallel to the output side of transformer T 4 , where the cathode of diode D 24 c is connected to pin 1 of transformer T 4 and the cathode of diode D 24 b is connected to pin 2 of transformer T 4 . The anodes of diodes D 24 b and D 24 c are both connected to ground. Diodes D 24 d and D 24 a are also connected in parallel to the output side of transformer T 4 , where the anode of diode D 24 d is connected to pin 1 of transformer T 4 and the anode of diode D 24 a is connected to pin 2 of transformer T 4 . The cathodes of diodes D 24 a and D 24 d are connected to CS+ (pin 4 ) of controller 18 as well as a series of resistors and a capacitor. For example, when transistor Q 2 a is turned on, the current from transformer T 4 will flow from pin 1 of the transformer, through diode D 24 d and through resistors R 21 , returning through D 24 b to pin 2 . A voltage representing the flow of this current through R 21 is connected to pin 4 of CS+ in controller 18 . When transistor Q 2 b is turned on, the current from transformer T 4 will flow from pin 2 of the transformer through D 24 a and through R 21 (to ground) and then returning through R 24 c to ground to pin 1 of T 4 . Again, the voltage on R 21 resistors is fed to CS+, the op-amp in controller 18 . Resistors R 21 , R 21 a , R 21 b , R 21 c , R 21 d , and R 21 e , and capacitor C 9 are all connected in parallel. The current output of diodes D 24 d and D 24 a are connected to the high side of resistors R 21 , R 21 a , R 21 b , R 21 c , R 21 d , and R 21 e , and capacitor C 9 . The low side of resistors R 21 , R 21 a , R 21 b , R 21 c , R 21 d , and R 21 e , and capacitor C 9 are connected to ground. This parallel resistor-capacitor circuit is used for the purpose of ensuring the voltage applied to CS+ (pin 4 ) of controller 18 is in the 1 volt range. Output Circuit The secondary-output side of transformer T 1 is connected to the DC load through a series of circuit elements making up the output rectifier and LC filter circuit 44 . The output circuit 44 includes capacitors C 19 , C 11 , C 13 A, C 12 , C 14 A, C 17 , and C 18 , schottky diodes D 11 a and D 11 b , diode D 12 , resistor R 29 , inductor L 2 , fuses F 2 , F 3 , and F 4 , inductor beads L 3 , L 4 , L 10 , and L 11 , and heavy gauge wires 105 , 106 , and 107 . The DC load is connected in parallel with capacitors C 11 , C 13 A, C 12 , C 14 A, C 17 , and C 18 (DC load capacitors), which are in series with inductor L 2 . The output circuit 44 is integral with the transformer secondary and includes two current loops with the current going in the same direction through inductor L 2 , the DC load capacitors, and the DC load ( FIG. 17 ). As further illustrated by FIG. 17 when transistor Q 2 a is turned on (Q 2 b is off) current I 1 will flow between pin 4 and pin 6 (primary-input side of transformer T 1 ) in a counter-clockwise direction. Current I 1 will cause current I 3 to flow between pin 8 and pin 1 (secondary side of transformer T 1 ) in a clockwise direction. Alternatively, when transistor Q 2 b is turned on (Q 2 a is off) current I 2 will flow between pin 4 and pin 5 (primary-input side of transformer T 1 ) in a clockwise direction. Current I 2 will cause current I 4 to flow between pin 8 and pin 2 (secondary side of transformer T 1 ) in a counter-clockwise direction. As illustrated the current (I 4 and I 3 ) applied to inductor L 2 is always going in the same direction. Further explained, when transistor Q 2 a is turned on, current flows in the secondary-output side of transformer T 1 from pin 1 through schottky diode D 11 a , through inductor L 2 . The DC load capacitors will be charged and current will be delivered to the DC load and back through pin 8 of the transformer. When transistor Q 2 b is turned on, current flows in the secondary side of transformer T 1 from pin 2 through schottky diode D 11 b , through inductor L 2 , the DC load capacitors will be charged and current will be delivered to the DC load and then back through pin 8 of the transformer. Resistor 29 and capacitor C 19 are connected in series between secondary-output pins 2 and 1 of transformer T 1 for the purpose of eliminating transient voltages. Inductor beads L 3 , L 4 , L 10 , L 11 , are connected between the secondary-output side of transformer T 1 and schottky diodes D 11 a and D 11 b . Inductor beads L 3 , L 4 , L 10 and L 11 are placed on the leads of D 11 A and D 11 B, for the purpose of reducing transient noise. The DC load capacitors which are connected in parallel with the DC load are arranged as follows. Capacitor C 11 is the main output capacitor. The positive plate of capacitor C 11 is connected to the positive terminal of the DC load P 4 and the negative plate is connected to the negative terminal of the DC load P 1 . The remaining capacitors are used for the purpose of reducing noise. Capacitor C 12 is connected in parallel with the DC load, where one plate of capacitor C 12 is connected to the positive terminal of the DC load P 4 , and the other plate of capacitor C 12 is connected to the negative terminal of the DC load P 1 . Capacitors C 13 A and C 14 A are connected in series, where one plate of capacitor C 13 A is connected to the positive terminal of the DC load P 4 , and one plate of capacitor C 14 A is connected to the negative terminal of the DC load P 1 . The remaining plates of capacitors C 13 A and C 14 A are connected to chassis ground. Capacitors C 17 and C 18 are also connected in series, where one plate of capacitor C 17 is connected to the positive terminal of the DC load P 4 , and one plate of capacitor C 18 is connected to the negative terminal of the DC load P 1 . The remaining plates of capacitors C 17 and C 18 are connected to chassis ground. Fuses F 2 , F 3 , and F 4 are connected in series with inductor L 2 and work in conjunction with diodes D 11 a and D 11 b to provide reverse battery protection. The illustrated embodiment of this invention also includes the use of heavy gauge wires which supplement the copper laminations on the circuit board. Heavy gauge wires 105 are connected directly between the negative output (terminal 8 ) of transformer T 1 and the negative terminal of DC load P 1 (i.e. DC negative output 88 ) Heavy gauge wires 106 are connected directly between schottky diodes D 11 A and the input of inductor L 2 . Heavy gauge wires 106 are also connected directly between schottky diodes D 11 B and the input of inductor L 2 . Heavy gauge wires 107 are connected directly between the output of inductor L 2 and fuses F 2 , F 3 , and F 4 . The output of fuses F 2 , F 3 , and F 4 are connected to the positive terminal of DC load P 4 (i.e. DC positive output 90 ). Waveforms FIG. 5 illustrates waveforms found at various points in the circuit of FIG. 17 under normal operating conditions. FIG. 5A shows the voltages across the two power transistors Q 2 a and Q 2 b during a complete cycle of operation. One voltage is the complement of the other. FIG. 5B shows the voltages across the primary windings of transformer T 1 during one complete cycle of switch operation. FIG. 5C illustrates the current waveforms 11 and 12 through the primary loops of FIG. 17 . FIG. 5D shows the current through inductor L 2 . FIG. 5F shows the secondary current I 4 through diode D 11 b. FIG. 5G shows the current through C 11 . FIG. 5H shows the voltage at the top of the circuit of FIG. 17 ; i.e., the top of L 2 . Permanent Reverse Battery Indicator The permanent reverse battery connection indicator 24 is diode D 12 . Diode D 12 and capacitor C 11 are connected in parallel. The cathode of diode D 12 is connected to the positive plate of capacitor C 11 which is connected to the positive terminal of the DC load P 4 . The anode of diode D 12 is connected to the negative plate of capacitor C 11 which is connected in to the negative terminal of the DC load P 1 . If a reverse battery connection is applied to the DC load output of the power converter, diode D 12 will blow before fuses F 2 -F 4 open circuit, permanently indicating that a reverse battery connection has occurred. If F 2 -F 4 blow, they may be replaced or reset and the converter 46 will be fully operational even if D 12 is not replaced. Packaging a Commercial Device Having described the preferred power conversion circuit, the packaging of a commercial embodiment will be described in detail with reference to FIGS. 18-26 . The commercial embodiment of converter 46 comprises a rectangular sheet metal housing 70 attached by screws to a finned aluminum extrusion 52 which forms the aforementioned heat sink for the FET's Q 2 a and Q 2 b , diode D 11 a and D 11 b , and the thermistor RT 1 . These components are held against a large flat surface 53 of heat sink 52 by spring clips 55 which are screwed into the heat sink extrusion in the manner shown in FIG. 19 . The fan 32 is mounted by screws 57 onto an end of the heat sink extrusion 52 in which a relief 59 of circular design has been machined. The surfaces of the relief 59 lie below the end surfaces 61 of the fins 65 and the screw base 63 on which the fan 32 is mounted. This relief creates an air gap between the fan motor 50 and the heat sink which prevents heat from the sink reaching the fan motor. Numerous vents 58 are formed in the top and back plates of the housing 70 . Flanges 84 are provided on both ends of housing 70 for mounting purposes. Fuses F 2 -F 4 are mounted outside the housing 70 for ease of replacement. Fuse Fx 1 , however, is inside the housing for reasons described above. The positive output terminals 90 and the negative output terminals 88 are mounted on the left side of housing 70 as shown in FIG. 22 . A power cord 98 extends from housing 70 through aperture 100 . The components in the circuit of FIG. 2 are mounted on a conventional circuit board 102 which is secured by fasteners within housing 70 . The board 102 has conductive traces on both sides as shown in FIGS. 25 and 26 . The inductor L 2 is mounted on board 102 as shown in FIG. 25 along with the transformer T 1 (central in FIG. 25 ). Two No. 12 gauge wires 104 run from the center tap of T 1 to a point 106 where they pass through a hole in board 102 and emerge on the other side as shown in FIG. 26 . From there to the negative output terminal 88 the wires overlie a copper trace and are soldered to the trace to lower the resistance of this high current path and increase the robustness of it as well. The leads 108 from L 2 to the fuses F 2 -F 4 and the positive outputs 90 are similarly constructed. FIG. 23 shows the converter 46 mounted within an RV 109 having a storage battery 114 . A power cord 112 brings 115 vac to the converter from a pedestal 111 of the type found in RV parks. The converter 46 is connected into the electrical system of the RV in a known manner. Referring again to FIG. 2 the circuit for the converter 46 is here equipped with a 4-wire terminal H 2 of which pin 4 is connected to the converter output fuses F 2 -F 4 via a 100 Ohm resistor R 57 . The terminal H 2 allows the converter to be connected to an external “management” system of the type described in U.S. Pat. No. 5,982,643 issued Nov. 9, 1999 to Thomas H. Phlipot and assigned to Progressive Dynamics, Inc. As is more completely described in the '643 patent, the management system includes a microcontroller which gives the owner the option of various operating modes and various converter output voltages; e.g., 13.6 v for normal operation, 13.2 v for storage, and 14.4 v for boost. Miscellaneous—Options FIG. 2 also illustrates a terminal H 4 connected to ground via R 51 , R 31 and C 21 . Terminal H 4 is a two-contact terminal which is shorted out with a small bridge wire if a gel cell is used in place of the normal lead-acid liquid storage battery 114 in the RV. This lowers the operating voltages of the converter 46 by 0.4 v and is a convenient option for owners who wish to use gel cell storage batteries While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiments but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as is permitted under the law. It is also to be understood that it is the inventor's intent to claim all novel subject matter contained within this disclosure. VALUES OF LISTED COMPONENTS C1 Capacitor 0.47 uF C10 Capacitor 220 uF C11 Capacitor 16 V C12 Capacitor 0.01 uF C13A Capacitor 0.01 uF C14A Capacitor 0.01 uF C15 Capacitor 2.2 nF C16 Capacitor 2.2 nF C17 capacitor 0.047 uF C18 capacitor 0.047 uF C19 capacitor 0.001 uF C2 capacitor 2.2 nF C20 capacitor 0.015 uF C22 capacitor 0.47 uF C24 capacitor 270 pF C25 capacitor 0.12 uF, 2% C26 capacitor 0.47 uF C27 capacitor 1000 pF C28 capacitor 0.1 uF C29 capacitor 2.2 nF C3 capacitor 2.2 nF C30 capacitor 0.47 uF C31 capacitor 2.2 nF C4a capacitor 820 uF, 250 V C4b capacitor 820 uF, 250 V C4c capacitor 820 uF, 250 V C5 capacitor 100 uF, 35 V C7 capacitor 0.1 uF C8 capacitor 0.1 uF C9 capacitor 0.01 uF D10 zener diode 13 V D11a schottky diode 40 A, 100 V D11b schottky diode 40 A, 100 V D12 diode D15a schottky diode 1 A, 20 V D15b schottky diode 1 A, 20 V D16a schottky diode 1 A, 20 V D16b schottky diode 1 A, 20 V D1a schottky diode 1 A, 100 V D23 zener diode 220 V, 5 W, 5% D24a diode 75 V, 150 mA D24b diode 75 V, 150 mA D24c diode 75 V, 150 mA D24d diode 75 V, 150 mA D27 schottky diode 1 A, 20 V D3 schottky diode 1 A, 20 V D4 diode 75 V, 150 mA D9 zener diode 15 V, 2 W DB1 diode bridge 20 A, 400 V Bridge F1 fuse 15 A F2 fuse 30 A F3 fuse 30 A F4 fuse 30 A Fx1 fuse 0.5 A L2 inductor 20 uH Q1 transistor 5 A, 40 V Q2a transistor 24 A, 500 V, .20 on resistance Q2b transistor 24 A, 500 V, .20 on resistance R1 resistor 390 Ohm, 5% R13 resistor 1.82K R14 resistor 16.2K R15 resistor 35.7K R16 resistor 1.8K, 5% R17 resistor 5.49K R18 resistor 15.4K R19a resistor 12.1K R19b resistor 12.1K R20 resistor 50 Ohm, 5%, 3 W R21 resistor 18.7 Ohm R21A resistor 422 Ohm R21B resistor 422 Ohm R21C resistor 845 Ohm R21D resistor 845 Ohm R21E resistor 1690 Ohm R23a resistor 15 Ohm, 5% R23b resistor 15 Ohm, 5% R24a resistor 1.5K, 5%, 10 W R24b resistor 1.5K, 5%, 10 W R25 resistor 1K, 5%, ½ W R26 resistor 31.2K or 30.1K R28 resistor 6.98K, ¼% R29 resistor 10 Ohm, 5% R2a resistor 453K R30 resistor 4.7K R33 resistor 3.24K R34 resistor 3.24K R37 resistor 100 Ohm, 5%, 10 W R38 resistor 84.5K, 0.5 W R39 resistor 866 Ohm R4 resistor 22.6K R40 resistor 97.6K R7 resistor 32.4K R8 resistor 499K RN1A resistor 16.2K RN1B resistor 47.5K RN1C resistor 9.53K RT1 thermistor 100K RT2 thermistor 1 Ohm T1 transformer 2:13:13:2:2 T2 CMC transformer custom T3 CMC transformer custom T4 transformer 80 MH U2 optically isolated amplifier FOD2741 U3A operational amplifier LM2902 U3B operational amplifier LM2902 U3C operational amplifier LM2902 U3D operational amplifier LM2902

A switch-type power converter comprising an PET switch operating in a variable duty cycle mode under the control of a Unitrode 3846 integrated circuit controller. Indications of excess input voltage and reverse battery connections are provided by circuits including an element which permanently changes state. A cooling fan mounted on a finned heat sink is operated in a variable speed mode. A single thermistor sensor provides inputs to both the fan speed control and a thermal shutdown circuit connected to shut down the gate drives to the FET switch in the event of a high temperature condition. Another shutdown function is provided in response to an input overvoltage condition by way of an operational amplifier. The converter uses foldback for short circuit protection and is compatible with microprocessor units to selectively provide multiple output voltage levels.

FIELD OF THE INVENTION [0001] The technology described herein pertains generally to kits and systems for steamers, and more particularly to devices and accessories directed to a roller iron steamer. BACKGROUND OF THE INVENTION [0002] Steam has been used for a variety of purposes, e.g. cleaning, disinfecting, wrinkle removal, loosening wallpaper. [0003] Steam is traditionally used when ironing clothes and other garments including curtains and furnishing covers with a steam iron that releases steam usually under the manual control of a user. Portable steamers employing steam wands are also known to remove creases and crinkles where steam is applied typically to hanging garments and the like. In this way, curtains can be treated with steam in situ or after being hung up following cleaning or washing. Wallpaper steamers are known for moistening old wallpaper so that it can be readily removed from walls prior to redecorating. Steam may also be used to clean and/or disinfect surfaces. [0004] Problems exist with current steaming devices and methods. [0005] Handheld steam irons are cumbersome and time consuming to use. [0006] The large machinery used by laundry professionals to press items are generally too costly and inconvenient for the average consumer. [0007] Household portable steamers work well to reduce superficial wrinkles in fabrics, but stubborn wrinkles are difficult to remove quickly with steam alone. It is also difficult to produce a crisp surface and make crisp creases in fabrics when using a household portable steamer alone. [0008] Wallpaper removal steamers are generally pointed at, or held directly on, wallpaper to be removed in order to loosen the wallpaper so it may then be pealed pack or scraped off. However, this method, to be effective, only works on a small area at a time. [0009] Additionally, there are numerous methods for cleaning and disinfecting flat surfaces such as walls and floors. One of these methods includes forced steam to remove surface impurities. This is effective for not only cleaning purposes but also for sanitizing and killing bacteria, viruses, mold and dust mites. However, one problem with this method is that, although steamers are effective in loosening dirt and debris, an additional method or step is required in order to remove the dirt and residue left behind. [0010] Related art that is directed to steamer devices includes the following patents and published patent applications. [0011] U.S. Pat. No. 1,690,757, issued to Steiner et al. on Nov. 6, 1928, discloses a device for steaming and brushing clothes in one operation, where the flow of steam may be readily controlled from the handle of the device. [0012] U.S. Pat. No. 2,164,085, issued to Rossen on Jun. 27, 1939, discloses a self-propelled electric iron. [0013] U.S. Pat. No. 2,743,541, issued to Schultz on May 1, 1956, discloses an attachment for a garment steaming and pressing machine. [0014] U.S. Pat. No. 2,849,736, issued to Kohle on Sep. 2, 1958, discloses a fabric steaming and brushing device. [0015] U.S. Pat. No. D222,502, issued to Madl, et al. on Oct. 26, 1971, illustrates a steam generating appliance for removing wrinkles from cloth articles. [0016] U.S. Pat. No. 3,622,246, issued to Grooms on Nov. 23, 1971, discloses a painting device comprising a functionally shaped reservoir provided with an aperture therein, a paint dispensing roller operably mounted on said reservoir and disposed near and within said aperture, wiper blades operably mounted on said reservoir and disposed near the peripheral surface of said roller, and handle means. [0017] U.S. Pat. No. 3,983,644, issued to Gowdy on Oct. 5, 1976, discloses a combination flash/flood boiler steam iron with a water tank having a fill opening and a liquid fill valve means to close the tank to ambient and having a steam generating soleplate with ports and boiler therein and a water valve to start and stop a metered flow of water to the boiler for generating flash steam. In this combination the improvement is added for selectively operating the iron with a flooded boiler comprising a separate flood valve means operable to partially empty the tank and fill the boiler to a flooded condition to generate saturated steam. A tubular means connects the boiler and water tank to balance both pressure within the iron and water level during flooded operation and to conduct all the generated steam to the tank interior. A steam passage distributing means connects to the soleplate ports and the distributing means is separated from the boiler generating means. Pressure control conduit means connects the tank interior and the distributing means whereby the iron operates dry with the valves closed to prevent steam generation; it operates with flash steam with the water valve open; and it operates flooded with saturated steam with the flood valve open; thus providing flexibility in several modes of operation. Additionally, a removable spout may be attached to the fill opening forming a steam nozzle so the iron may be used as a fabric steamer on vertically hanging garments. [0018] U.S. Pat. No. 4,640,028, issued to Nakada et al. on Feb. 3, 1987, discloses a portable travel electric steam iron which also functions as a steamer having an aperture provided in a rear portion of the bottom of a water tank which supplies water into steam generating chambers from the water tank. Water dripping through the aperture is received by a water receiving surface provided on the center or on the front side of the center of a base. A handle which includes two straight positions separated by a bend is securable to an iron main body both in the operative position and storage position. An actuator for opening and closing an aperture is disposed in a space above the water tank, in the vicinity of a fixing portion at which the handle is fixed to the iron main body, thus providing a compact construction which is easy to handle. [0019] U.S. Pat. No. 4,855,568, issued to Wilkins on Aug. 8, 1989, discloses a hand-held wallpaper steamer for use in wallpaper stripping having a housing of two-part clam shell construction, a base portion with a floor and a peripheral wall to form a chamber open at one face. The clam shells are contoured to receive the base portion at the open end of the housing to close that end. The clam shells are shaped to form a handle spaced from the base portion and extending in a direction generally parallel to the base portion. The clam shells are also shaped to accommodate a removable water tank. [0020] U.S. Pat. No. 4,875,301, issued to Adams on Oct. 24, 1989, discloses a method and apparatus for removing wrinkles from a table skirt includes a cylinder capable of holding the table skirt and having a porous portion. The apparatus further includes devices for rotating the cylinder and for delivering steam from an outside source through the cylinder so that the steam passes through the porous portion and removes the wrinkles. [0021] U.S. Pat. No. D319,121, issued to Muller on Aug. 13, 1991, illustrates a garment steamer. [0022] U.S. Pat. No. 5,609,047, issued to Hellman, Jr. et al. on Mar. 11, 1997, discloses a portable garment steaming device for use in the home which emits steam through a retractable nozzle plate of a safety nozzle assembly which when retracted prevents against accidental touching of the hot nozzle plate. The garment steaming device also includes a clothes hanger assembly for hanging the article of clothing to be steamed. A water bottle compartment for supplying water to be generated as steam for the safety nozzle assembly is further provided which is detachably mounted for refilling. [0023] U.S. Pat. No. 5,832,639, issued to Muncan on Nov. 10, 1998, discloses a portable garment finishing apparatus of the technology disclosed herein comprises a water reservoir, a water conversion device, and a conventional steam heated iron. The present apparatus is designed to operate from a single 115 v power source, such as an ordinary wall outlet. Using a water-level probe in connection with a circuit board having a relay switch, a pump is regulated in its supply of water from the reservoir to the steam chamber in the conversion device. Water continuously is converted to steam and constantly released to the iron where it maintains the iron temperature and may be released onto a garment for finishing. The steam returns to the conversion device where it condenses in a steam trap valve for subsequent return to the reservoir, where it may be recycled. [0024] U.S. Pat. No. 6,061,935, issued to Lee on May 16, 2000, discloses a dual appliance for steam treating garments having a central reservoir and an electrical water pump to supply water to a steamer or a steam iron. Separate braided flexible cables supply water and power to the steamer and to the steam iron, to which the respective cables are respectively permanently connected. Plugs are provided at the ends of the cables for connection to a socket. [0025] U.S. Pat. No. D426,924, issued to Joiner et al. on Jun. 20, 2000, illustrates a steamer head. [0026] U.S. Pat. No. 6,622,404, issued to Valiyambath on Sep. 23, 2003, discloses a steamer arrangement comprising a cordless steaming device and a stand for holding the steaming device, the steaming device having a water tank, the stand having an electrically heated boiler, the steaming device and the stand being provided with mechanical coupling means, including valves for coupling the water tank of the steaming device to the boiler of the stand for obtaining a fluid communication between the boiler and the water tank when the steaming device is attached to the stand. When the steaming device is attached to the stand, steam flows from the boiler to the water tank, resulting in high-pressure/temperature steam in the water tank. Detached from the stand the cordless steaming device can be used directly for steaming. The cordless steaming device may be a cordless iron with the soleplate heated electrically, while simultaneously steam is charged when the iron is placed on the stand. [0027] U.S. Patent Publication No. 2004/0144140, inventor Lee, published on Jul. 29, 2004, discloses a steamer attachment which allows a user to selectively dispense steam from a steamer. The attachment broadly comprises a body, a first and second steam distributor located in a head of the body, and a valve located in a handle of the body. The first distributor preferably comprises a nozzle to concentrate the steam and a brush. The second distributor preferably comprises a plurality of holes to disperse the steam. The second distributor may also include a detachable diffuser to further disperse the steam. The valve preferably opens a first path toward the first distributor before closing a second path toward the second distributor. Thus, the steam always has at least one available path, in order to prevent pressure buildup within the steamer. [0028] U.S. Pat. No. 6,886,373, issued to Carrubba et al. on May 3, 2005, discloses a garment steamer for domestic use that cooperates with a variety of different attachments to provide a variety of different steam or vapor emitting effects. The garment steamer also has an ionic and/or ozone generating/emitting feature to facilitate neutralizing odor and removing undesirable particulate from a garment. The garment steamer may also have a hanger and rod assembly in which a collapsible hanger selectively cooperates with a telescopic rod, which is connected to a base, such that the hanger can be selectively positioned at any location along the height of the rod and/or disengaged from the rod. The garment steamer also includes a fluid heating assembly enclosed in the base, a separable fluid container in separable fluid communication with the fluid heating assembly, and a separable hose in separable fluid communication with the fluid heating assembly, as well as with the variety of different attachments. [0029] U.S. Pat. No. 6,986,217, issued to Leung et al. on Jan. 17, 2006, discloses a hand held appliance for use in applying steam to a garment or other item made of fabric includes a pump, a boiler and a switch. Power is applied through the switch to the pump. The pump pumps water from the water tank to the boiler. The water is converted to steam in the boiler and is expelled from the appliance through a set of nozzles. The appliance may include optional attachments for performing other operations on garments or fabric, for example, applying pressure, brushing, scrubbing, or lint removal. [0030] U.S. Pat. No. 7,051,462, issued to Rosenzweig on May 30, 2006, discloses a combination steam cleaner and steam iron includes a steam generator, a steam cleaner and a steam iron. The steam generator includes a voltage control device serially connected to a boiler element for boiling water to produce steam. The steam cleaner is attachable to the steam generator, a nozzle that dispenses the steam, and a circuit designed to supply power to the boiler element when the steam cleaner is attached to the steam generator. The steam iron is attachable to the steam generator, includes an iron heating element for heating the iron, and includes a circuit designed to supply power to the iron heating element in addition to supplying power to the boiler element, when the steam iron is attached to the steam generator. The steam generator also includes a steam release valve that supplies the steam and which is controlled by respective switches within the steam cleaner and iron. [0031] Generally available portable steaming appliances include those provided by TOBI®, CONAIR®, JIFFY®, ROWENTA®, ACE HI®, EURO-PRO®, STEAM FAST®, SAMSONITE®, HOMEDICS®, SUNBEAM®, RELIABLE®, SHARPER IMAGE®, SHARK®, SCUNCI®, and others. [0032] While these patents, published patent applications, other previous methods and devices have attempted to solve the problems that they addressed, none have utilized or disclosed a roller iron steamer accessory kit and system capable of loosening wall paper, cleaning, sanitizing and pressing, as does embodiments of the technology disclosed herein. [0033] It is therefore an aspect of the technology described herein to provide a new and improved roller iron steamer accessory kit and system which has all the advantages of the prior art steaming devices and none of the disadvantages. [0034] Therefore, a need exists for a roller iron steamer accessory kit and system with these attributes and functionalities. The roller iron steamer accessory kit and system according to embodiments of the technology disclosed herein substantially departs from the conventional concepts and designs of the prior art. It can be appreciated that there exists a continuing need for a new and improved roller iron steamer accessory kit and system which can be used commercially. In this regard, the technology disclosed herein substantially fulfills these objectives. BRIEF SUMMARY OF THE INVENTION [0035] In general, the technology described herein features a roller iron steamer accessory kit and system directed to the removing of wrinkles in fabric, the loosening of wallpaper, the cleaning and/or sanitizing of substantially flat surfaces. In a typical embodiment, the elements of the kit include at least one roller iron device, either configured to adapt to a portable steamer or including at least one adapter to mate the roller iron device to an element of the portable steamer that provides for the passage of steam, e.g. a wand. [0036] The general purpose of the technology disclosed herein, which will be described subsequently in greater detail, is to provide a handheld method for ironing or pressing fabric, cleaning, sanitizing, and as an aid in the removal of wallpaper, using a roller type device. [0037] In one embodiment of the technology disclosed herein, the roller device pertains to a steamer-specific attachment to an already existing steamer, where the roller device is formed on one end to attach directly to a corresponding end to an element of a specific model of a steamer, such as a steamer wand. [0038] In another embodiment of the technology disclosed herein, the roller device pertains to a generic roller device plus an adapter for a specific steamer model where the adapter connects one end of the generic roller device to a corresponding element of the specific steamer model, such as a steamer wand. [0039] In yet another embodiment of the technology disclosed herein, the roller device is in itself an iron/steamer assembly with its own source of power, water reservoir, steam generation and steam control. [0040] In an exemplary embodiment, the technology disclosed herein is comprised of a roller assembly having at least one roller element, a roller housing element, and a connection element so the roller assembly may be attached to a portable steamer. [0041] Additional element or features include the following: the roller element may be configured to be removed from the housing element the roller assembly may include a sleeve element the roller element may include a roller cover element, which may be placed over the roller for cleaning purposes the roller assembly may include an extension element, e.g. a handle or pole, which can be fastened to, or screwed into, the connection element to allow a user to roll over large areas, or to reach hard-to-get-to places the roller iron steamer accessory kit may include a storage tray element the roller iron steamer accessory kit may include a protective cover element the roller iron steamer accessory kit may include a squeegee/scraper element that may be placed along one or more edges of the housing element the adapter may have a handle disposed thereon the roller iron steamer accessory kit may include connective tubing a roller cover may be utilized for pressing delicate fabrics [0052] One way the technology disclosed herein can be used is as follows: While the steamer is unplugged, attach the roller attachment to the steamer by utilizing tubing, adaptors, or by screwing or snapping into place. Fill the water chamber and set the temperature settings of the unit using specific manufactures instructions. Once the unit has sufficiently heated up, press, iron, or steam material by rolling the roller attachment over the desired area. [0056] Another way the technology disclosed herein can be used is as follows: While the steamer is unplugged, attach the roller attachment to the steamer by utilizing tubing, adaptors, or by screwing or snapping into place. Fill the water chamber and set the temperature settings of the unit using specific manufactures instructions. Once the unit has sufficiently heated up, roll the attachment over area to be cleaned. The squeegee/scraper and the roller covers may also be used for the purpose of cleaning and removing debris. [0061] Yet another way the technology disclosed herein can be used is as follows: While the steamer is unplugged, attach the roller attachment to the steamer by utilizing tubing, adaptors, or by screwing or snapping into place. Fill the water chamber and set the temperature settings of the unit using specific manufactures instructions. Once the unit has sufficiently heated up, roll the attachment over area of wallpaper to be removed. The squeegee/scraper may also be used for the purpose of removing wallpaper. [0066] The technology disclosed herein has the following advantages: easy to use adapted to connect to various types of steamers convenient portable able to be used on large areas easily configured for attaching an extension to the unit for use while working on large, high, or hard to reach area provides a cost saving alternative to professional ironing may be easily and efficiently manufactured and marketed is of durable and reliable construction has multiple uses and applications [0077] Another embodiment of the technology disclosed herein is comprised of a cylindrical rotary iron with at least one arm. There is a heating element or elements surrounded by at least one heat conducting, ridged, cylindrical roller. There is at least one handle and a cord with a plug. This embodiment may also be configured to have a temperature control element, an on-and-off element, a self-contained water chamber, an external water storage element, a sleeve or roller cover can be used over the roller for the purpose of cleaning, an extension element, a squeegee/scraper element. [0078] This embodiment may be used as follows: Plug the device into the wall socket and turn the unit on. Set the unit to the desired temperature setting. Allow the device to heat up and grasping the handle of the device. Place the roller portion on the fabric to be ironed. Roll the iron over the area to be ironed until the wrinkles ore gone. The roller cover may also be utilized for pressing delicate fabrics. [0085] Another way to use this embodiment is as follows: Fill the water chamber with water. Plug the device into a wall socket and turn the unit on. Set the unit to the desired temperature setting. Allow the device to heat up. Holding the handle of the device, steam or spray the fabric while ironing. The roller cover may also be utilized for pressing delicate fabrics. [0092] Yet another way to use this embodiment is as follows: Fill the water chamber with water and place a roller cover over the rotary portion of the device. Plug the device into the wall socket and turn the unit on. Allow the unit to heat up to the desired temperature. Holding the handle of the device, steam and roll over surface for the purpose of cleaning, disinfecting or in order to kill dust mites. The squeegee/scraper and the roller covers may also be used for the purpose of cleaning and removing debris. [0098] Still another way to use this embodiment is as follows: Fill the water chamber with water. Attach an extension element, e.g., a pole Plug the device into a wall socket and turn on the device. Set to the appropriate temperature setting. Allow the unit to heat up. Holding the handle of the device, steam and roll over surface for the purpose of loosening wallpaper. The squeegee/scraper may also be used for the purpose of removing wallpaper. [0106] There has thus been outlined, rather broadly, the more important features of the technology disclosed herein in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the technology disclosed herein that will be described hereinafter and which will form the subject matter of the claims appended hereto. [0107] In this respect, before explaining at least one embodiment of the technology disclosed herein in detail, it is to be understood that the technology disclosed herein is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The technology disclosed herein is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. [0108] As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the technology disclosed herein. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the technology disclosed herein. [0109] Further, the purpose of the foregoing abstract is to enable the U.S. Patent and Trademark Office and the public generally, and especially the scientists, engineers and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. The abstract is neither intended to define the invention of the application, which is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way. [0110] The foregoing patent and other information reflect the state of the art of which the inventor is aware and are tendered with a view toward discharging the inventor's acknowledged duty of candor in disclosing information that may be pertinent to the patentability of the technology disclosed herein. It is respectfully stipulated, however, that the foregoing patent and other information do not teach or render obvious, singly or when considered in combination, the inventor's claimed invention. [0111] These aspects and advantages, together with other objects of the technology disclosed herein, along with the various features of novelty which characterize the technology disclosed herein, are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the technology disclosed herein, its operating advantages and the specific objects attained by its uses, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated preferred embodiments of the technology disclosed herein. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS [0112] The technology described herein, together with further advantages thereof, may best be understood by reference to the following description of the simplest form of the technology described herein, taken in conjunction with the accompanying drawings in which: [0113] FIG. 1 illustrates a perspective view of a roller iron steamer assembly with a portable steamer specific adapter, according to an embodiment of the technology disclosed herein. [0114] FIG. 2 illustrates a perspective view of a roller iron steamer assembly, according to an embodiment of the technology disclosed herein. [0115] FIG. 3 illustrates a perspective view of a roller iron steamer assembly, according to an embodiment of the technology disclosed herein. [0116] FIG. 4 illustrates a perspective view of a roller iron steamer assembly showing a releasable roller, according to an embodiment of the technology disclosed herein. [0117] FIG. 5 illustrates a perspective view of a roller iron steamer device having elements for power, steam control and water reservoir (not shown), according to an embodiment of the technology disclosed herein. [0118] FIG. 6 illustrates a perspective view of a roller iron steamer device having elements for power, steam control and water reservoir (not shown) plus extension tubing and extension pole, according to an embodiment of the technology disclosed herein. [0119] FIG. 7 illustrates a perspective view of a roller iron steamer device having elements for power, steam control and water reservoir, showing a releasable cover for the roller, according to an embodiment of the technology disclosed herein. [0120] FIG. 8 illustrates a perspective view of a roller iron steamer device having elements for power, steam control and water reservoir, showing a releasable cover for the roller, according to an embodiment of the technology disclosed herein. [0121] FIG. 9 illustrates a perspective view of a roller iron steamer device having a squeegee and sprayer elements. [0122] FIG. 10 illustrates a perspective view of a roller iron steamer device with the sprayer element activated. DETAILED DESCRIPTION OF THE INVENTION [0123] The technology disclosed herein will now be described in detail with reference to at least one preferred embodiment thereof as illustrated in the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the technology disclosed herein. It will be apparent, however, to one skilled in the art, that the technology disclosed herein may be practiced without some or all of these specific details. In other instances, well known operations have not been described in detail so not to unnecessarily obscure the technology disclosed herein. [0124] Referring to the drawings, FIGS. 1-8 , wherein like reference numerals designate corresponding parts throughout the several figures, in an exemplary embodiment a roller iron steamer accessory kit is comprised of roller iron assembly 100 , a roller iron assembly adapter 200 ; a roller iron sleeve 300 ; a storage tray 400 (not shown), a squeegee/scraper assembly 500 ; and a container 600 (not shown), where the roller iron assembly 100 includes a first housing having a first housing distal end and a first housing proximal end, and where the roller iron assembly adapter 200 includes a second housing having a second housing distal end and a second housing proximal end, where the first housing proximal end is configured to releaseably connect with the second housing distal end, and where the second housing proximal end is configured to releasably connect with a wand of a conventional portable steamer, where the first housing distal end is configured to rotatably hold a roller having an array of steam escape holes disposed thereon, and where the first housing distal end is configured to releasably hold the roller 120 , and where the roller iron sleeve 300 is steam permeable and releaseably covers the roller 120 , and where the squeegee/scraper assembly 500 is configured for attaching laterally to the first housing. [0125] In another embodiment a roller iron steamer kit 010 comprises a roller iron assembly 100 ; and a plurality of a roller iron assembly adapter 200 ; where each roller iron assembly adapter 200 releasably connects the roller iron assembly 100 to a different model of a portable steamer. These portable steamers include, but are not limited to TOBI®, CONAIR®, JIFFY®, ROWENTA®, ACE HI®, EURO-PRO®, STEAM FAST®, SAMSONITE®, HOMEDICS®, SUNBEAM®, RELIABLE®, SHARPER IMAGE®, SHARK®, or SCUNCI® portable steamers. The roller iron steamer kit 010 may be further comprised of a roller iron sleeve 300 , a storage tray 400 (not shown), a squeegee/scraper assembly 500 and/or a container 600 (not shown) for holding the contents of the roller iron steamer kit 010 elements. [0126] In another embodiment of the technology disclosed herein a roller iron steamer kit 010 comprises a roller iron steamer attachment 100 operable to join with a wand of a portable steamer to dispense steam from the portable steamer, the roller iron assembly comprising a body having a handle and a head, wherein the head includes a laterally rotating cylinder and an opening permitting the rotating cylinder to contact a surface. The roller iron steamer kit 010 may be further comprised of a roller iron sleeve 300 , a storage tray 400 (not shown), a squeegee/scraper assembly 500 , and/or a container 600 (not shown) for holding the contents of the roller iron steamer kit 010 . The container may be, but is not limited to, a bag or a case. [0127] In some embodiments the roller iron steamer attachment may have a water reservoir 190 for steam generation. In other embodiments the roller iron steamer attachment channels steam from a steamer. [0128] With respect to the above description, it is to be realized that the optimum dimensional relationships for the parts of the technology disclosed herein, to include variations in size, materials, shape, form, function and the manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the technology disclosed herein. [0129] Therefore, the foregoing is considered as illustrative only of the principles of the technology disclosed herein. Further, since numerous modification and changes will readily occur to those skilled in the art, it is not desired to limit the technology disclosed herein to the exact construction and operation shown and described, and accordingly, all suitable modification and equivalents may be resorted to, falling within the scope of the technology disclosed herein. [0130] The foregoing description and drawings comprise illustrative embodiments of the technology disclosed herein. Having thus described exemplary embodiments of the technology disclosed herein, it should be noted by those skilled in the art that the within disclosures are exemplary only, and that various other alternatives, adaptations and modifications may be made within the scope of the technology disclosed herein. Merely listing or numbering the steps of a method in a certain order does not constitute any limitation on the order of the steps of that method. Many modifications and other embodiments of the technology described herein will come to mind to one skilled in the art to which this technology disclosed herein pertains having the benefit of the teachings presented in the foregoing description and the associated drawings. Although specific terms may be employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation. Accordingly, the technology disclosed herein is not limited to the specific embodiments illustrated herein, but is limited only by the following claims.

A roller iron steamer accessory kit is disclosed. The kit facilitates the removing of wrinkles in fabric, the loosening of wallpaper, and the cleaning and/or sanitizing of surfaces. The elements of the kit include at least one roller iron device, either configured to adapt to a portable steamer or including at least one adapter to mate the roller iron device to an element of the portable steamer that provides for the passage of steam, e.g. a wand.

CROSS-REFERENCES TO RELATED APPLICATIONS [0001] This application is a continuation of U.S. patent application Ser. No. 14/542,066 (Attorney Docket No. 28863-718.301), filed Nov. 14, 2014, now U.S. Pat. No. ______, issued on ______, 2016, which is a continuation of U.S. patent application Ser. No. 13/452,656 (Attorney Docket No. 28863-718.502), filed Apr. 20, 2012, now U.S. Pat. No. 8,911,472, issued on Dec. 16, 2014, which is a continuation-in-part of application Ser. No. 12/492,779 (Attorney Docket No. 28863-718.201), filed on Jun. 26, 2009, which claims the benefit of provisional Application No. 61/077,104 (Attorney Docket No. 28863-718.101), filed on Jun. 30, 2008, the full disclosures of which are incorporated herein by reference. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates generally to medical devices and methods. More particularly, the present invention relates to apparatus and protocols for closing arteriotomies and other vascular wall penetrations. [0004] Angiography, angioplasty, atherectomy, and a number of other vascular and cardiovascular procedures are performed intravascularly and require percutaneous access into the patient's vasculature, most often into the arterial vasculature. The most common technique for achieving percutaneous access is called the Seldinger technique, where access to an artery, typically the femoral artery in the groin, is first established using a needle to form a “tract,” i.e., a passage through the tissue overlying the blood vessel. The needle tract is then dilated, and an access sheath is placed into the dilated tract and through a penetration in the vascular wall, such as an arteriotomy to allow the introduction of guidewires, interventional catheters, catheter exchange, and the like to perform the desired procedure. [0005] Once the desired procedure is completed, the access sheath must be removed and the arteriotomy or other vascular wall penetration closed. For many years, such closure was achieved by applying manual pressure onto the patient's skin over the site of the vascular wall penetration. Patients, however, have often been heparinized to limit the risk of thrombosis during the procedure, and clotting of the vascular wall penetration can often take an extended period, particularly when the penetration is relatively large for performing procedures needing larger diameter catheters. For these reasons, improved methods for closing and sealing vascular wall penetrations have been sought. [0006] In the last decade, a variety of new procedures and devices have been introduced to more effectively seal the arteriotomies and other vascular wall penetrations associated with percutaneous intravascular access. Some of the new protocols rely on suturing, others rely on clipping, plug placement, energy-based closure, and the like. One problem with many of the new procedures, however, is that they leave material behind, and/or induce scar formation at the access site. Both the leaving of materials and the formation of scar tissue can be problematic, particularly if the patient requires subsequent access to the same vascular site for performance of another vascular or cardiovascular procedure. [0007] For these reasons, it would be advantageous to provide protocols and apparatus which would leave no material behind and which would further limit the likelihood of forming scar tissue after the procedure is complete. One device that can meet these objectives in many instances is the Boomerang Catalyst™ system available from Cardiva Medical, Inc., assignee of the present application. The Boomerang Catalyst system includes an expansible element at its tip for providing temporary hemostasis when placed in the blood vessel adjacent to the vascular wall penetration. The catheter further includes a catalytic material on its shaft which helps induce hemostasis and clotting within the tissue tract immediately above the vessel wall penetration. The construction and use of this system is described in copending application Ser. No. 11/302,951 (Attorney Docket No. 021872-002200US); Ser. No. 11/772,718 (Attorney Docket No. 021872-002210US); and Ser. No. 11/614,276 (Attorney Docket No. 021872-002400US), the full disclosures of which are incorporated herein by reference. [0008] Despite the success of the Boomerang Catalyst systems, there may still be some instances where hemostasis is not achieved as rapidly. For this reason, it would be desirable to provide further improved systems and protocols for closing and sealing arteriotomies and other vascular wall penetrations, where the closure may be achieved with rapid hemostasis, with a minimum risk of scar formation, and without leaving any materials or implants permanently behind in the vessel or the tissue tract. At least some of these objectives will be met by the inventions described below. [0009] 2. Background of the Invention [0010] U.S. Pat. No. 7,335,219 describes a device for delivering a plug of hemostatic material to a location just above a blood vessel wall penetration. The hemostatic material is encapsulated in a dissolvable structure and a non-expandable control tip assembly helps advance the device through the tissue tract and may also provide hemostasis and bleedback. US2007/0123817 and U.S. Pat. No. 7,008,439 describe apparatus for sealing a vascular wall penetration. Other apparatus for closing blood vessel wall punctures are described in U.S. Pat. Nos. 4,744,364; 5,061,271; 5,728,133; and 7,361,183 and U.S. Published Patent Application Nos. 2003/0125766; 2004/0267308; 2006/0088570; 2007/0196421; and 2007/0299043. The incorporation of anti-proliferative materials in hemostatic materials for blood vessel closure and other purposes is described in U.S. Pat. Nos. 7,025,776 and 7,232,454; 6,554,851; and U.S. Published Patent Application Nos. 2005/0004158; 2005/0038472; 2007/0060895/2007/0032804; and 2008/0039362. BRIEF SUMMARY OF THE INVENTION [0011] The present invention provides apparatus and methods for sealing a blood vessel wall penetration with little or no material being permanently left behind and with a reduced likelihood of scar tissue formation. The invention relies on placing a hemostatic implant in the tissue tract at a location over the vascular wall penetration while the penetration is temporarily closed with an expansible occlusion element present in the blood vessel lumen. The hemostatic implant is preferably biodegradable, typically over a period of less than one year, preferably over a period of less than six months, more preferably less than three months, and may carry an anti-proliferative agent to reduce scar formation. Additionally or alternatively, the implant may carry a coagulation promoter to accelerate hemostasis and/or radiopaque material to enhance visualization. The use of the hemostatic implant together with the temporary hemostasis provided by the occlusion element increases the likelihood that even relatively large vascular penetrations can be successfully closed and usually reduces the time needed to achieve such closure. [0012] Apparatus according to the present invention for sealing a blood vessel wall penetration disposed at an end of a tissue tract comprise a shaft, an occlusion element, a hemostatic implant, and a protective sleeve. The shaft has a proximal and distal end and is adapted to be introduced through the tissue tract so that the shaft distal end can be positioned within the blood vessel lumen. Usually, the shaft will be adapted so that it can be introduced through the vascular access sheath which is in place after performance of the interventional procedure. [0013] The occlusion element is disposed near the distal end of the shaft and is configured so that it may be shifted between a radially contracted configuration which facilitates introduction through the tissue tract and a radially expanded configuration for deployment within the blood vessel to occlude the penetration and provide temporary hemostasis. The hemostatic element could be a balloon or other inflatable structure, but will more usually be an expansible braid, coil, or other element which may be radially expanded by axial foreshortening. Typically, the shaft comprises an outer tube and an inner rod where a distal end of the occlusion element is attached to a distal end of the rod and a proximal end of the occlusion element is attached to a distal end of the outer tube. Thus, the occlusion element can be expanded and contracted by retracting and advancing the rod relative to the tube, respectively. The preferred occlusion element comprises a braided mesh covered with an elastic membrane. As described thus far, the shaft and occlusion element may be similar or identical to those described in the earlier referenced commonly owned patent applications. [0014] The hemostatic implant of the present invention is disposed over an exterior surface of the shaft proximal to the occlusion element. The protective sleeve is retractably disposed over the hemostatic implant to protect it while the shaft is being introduced to the tissue tract. The hemostatic implant will typically comprise a body or wrapped sheet which partially or fully circumscribes the shaft, but other configurations could also be utilized. In a first embodiment, the hemostatic implant comprises a cylindrical body which is coaxially mounted about the shaft of the delivery device. Such fully circumscribing implants, however, can have difficulty being released from the shaft after they are exposed and hydrated. Thus, it will often be preferable to provide hemostatic implant configurations where the body partially circumscribes the shaft or is disposed in parallel to the shaft. When the implant is not disposed about the shaft, release upon rehydration will be greatly simplified as the rehydrated implant will lie adjacent to the shaft, allowing the shaft and the collapsed occlusion element to be drawn proximally past the rehydrated hemostatic implant with minimum interference. The hemostatic implant typically comprises a swellable, biodegradable polymer which swells upon hydration. Hydration is prevented when the polymer is introduced by the protective sleeve. The polymer hydrates and swells when the sleeve is retracted within the tissue tract, exposing the polymer to the body fluids. Suitable polymers include biodegradable hydrogels such as polyethylene glycols, collagens, gelatins, and the like. [0015] An anti-proliferative agent will usually be distributed within or otherwise carried by the material of the hemostatic implant. As most anti-proliferative agents, such as sirolimus, paclitaxel, and the like, are hydrophobic, it will usually be desirable to incorporate the anti-proliferative agents in a carrier, such as a biodegradable polymer, such a polylactic acid (PLA), poly(lactide-co-glycolide), and the like. The anti-proliferative agents may be incorporated into pores of polymeric beads or other structures which are dispersed or distributed within the biodegradable hydrogel or other swellable polymer. In certain embodiments, the anti-proliferative agents may be incorporated into nanoparticles, typically having dimensions in the range from 10 nm to 100 .mu.m. [0016] Agents useful as coagulation promoters, such as thrombin, tissue factors, components of the clotting cascade, and the like may also be incorporated into the body of the hemostatic implant. In some instances, it may be desirable to incorporate such coagulation promoters into particulate or other carriers as described above with regard to the anti-proliferative agents. [0017] In addition to the anti-proliferative agents and the coagulation promoters, the hemostatic implants of the present invention may further incorporate radiopaque materials in or on at least a portion of the implant body. For example, a radiopaque material, such as barium, may be incorporated into the polymer, either by dispersion or chemical bonding. Alternatively, radiopaque rings, markers, and other elements, may be attached on or to the hemostatic implant, for example at each end of the implant to facilitate visualization of the implant as it is being implanted. Additionally or alternatively, radiopaque markers may be provided on the tube or shaft which carries the hemostatic implant so that the marker(s) align with a portion of the implant, typically either or both ends of the implant, prior to deployment. [0018] In a preferred aspect of the present invention, the protective sleeve is held in place by a latch mechanism while it is being introduced. A separate key element is provided to release the latch mechanism and permit retraction of the sleeve after the device has been properly placed through the tissue tract and into the target blood vessel. The latch will be disposed on the shaft and will engage the protective sleeve to immobilize the sleeve during introduction. The key, which is usually slidably disposed on the shaft proximal of the latch, is able to shift the latch between a locking configuration where the sleeve is immobilized and an open configuration which allows the sleeve to be proximally retracted. Usually, the latch is spring-loaded to deflect radially outwardly from the shaft in a manner which engages the sleeve. The key is then adapted to radially depress the latch to release the sleeve. In a preferred embodiment, the latch and key mechanism will extend over a proximal portion of the shaft having a length sufficient to allow manual access to the key latch even when the shaft is placed in the tissue tract. [0019] In a further preferred aspect of the present invention, a backstop structure is provided on the shaft to engage the hemostatic implant to immobilize the implant while the sleeve is being proximally refracted. The backstop usually comprises a tube disposed on or coaxially over the shaft and having a distal end which engages a proximal end of the hemostatic implant. The backstop engages the hemostatic implant to prevent accidental dislodgement while the occlusion element is being proximally retracted through the implant. The backstop may include a space or receptacle for receiving the retracted occlusion element, allowing the backstop to be held in place until the occlusion element has been fully retracted through the hemostatic implant. [0020] The protective sleeve of the present invention may comprise an outer sleeve and a separately retractable inner release sheath. The outer sleeve and inner release sheath are usually mounted coaxially so that the outer sleeve may be retracted over the inner release sheath while the inner release sheath remains stationary over the implant and acts as a friction barrier between the outer sleeve and implant. Without the inner release sheath, the protective sleeve, which applies the compressive and constrictive forces to the hemostatic implant, could stick to the hemostatic implant and make retraction of the protective sleeve and deployment of the implant difficult. The inner release sheath is preferably axially split so that, once the outer sleeve is retracted, the inner release sheath opens to release the implant and facilitate retraction of the release sheath. In preferred embodiments, the outer sleeve can engage the inner release sheath after the outer sleeve has been partly retracted. During the remainder of the outer sleeve retraction, the outer sleeve will then couple to and retract the inner release sheath to fully release the hemostatic implant. In addition to the use of the inner release sheath, the distal end of the protective sleeve may be sealed with a biodegradable substance, such as a glycerin gel, which can inhibit premature hydration of the hemostatic implant prior to release. [0021] In a further preferred aspect of the present invention, the key of the latch mechanism can include a coupling element which attaches to the protective sleeve as the key is advanced and the latch is released. After the key couples to the protective sleeve, the key can be used to retract the protective sleeve. That is, rather than having to reposition the hand to grab and retract the protective sleeve which would also retract the mating key, only the key needs to be held and retracted. [0022] Methods according to the present invention for sealing a blood vessel penetration disposed at the end of a tissue tract comprise providing an apparatus including a shaft, an occlusion element, and a hemostatic implant disposed on an exterior surface of the shaft. The shaft is introduced through the tissue tract to position the occlusion element in the lumen of the blood vessel and the hemostatic implant within the tissue tract. The hemostatic implant is covered by a protective sleeve while the shaft is being introduced through the tissue tract, and the occlusion element is deployed to temporarily inhibit blood flow from the blood vessel into the tissue tract. The protective sleeve is then retracted to expose the hemostatic implant, where the implant typically absorbs fluid and expands to provide the desired seal within the tissue tract. After the hemostatic implant has expanded sufficiently, the occlusion element will be collapsed, and the shaft and collapsed occlusion element withdrawn leaving the hemostatic implant in the tissue tract. As described above, it will usually be preferred to position the hemostatic implant laterally or to the side of the shaft which carries the occlusion element. By thus positioning the occlusion element to bypass the hydrated hemostatic implant, withdrawal of the collapsed occlusion element past the hydrated hemostatic implant can be greatly facilitated. Preferably, the material of the hemostatic implant will degrade over time, preferably over a period of less than one year, more preferably over a period of less than six months, usually less than three months, leaving no material behind at the vascular access point. [0023] In a preferred aspect of the methods of the present invention, the protective sleeve is latched to the shaft while the shaft is introduced. By “latched” is meant that the sleeve will be fixed or immobilized to the shaft by some mechanical link, where the link may be selectively disconnected or “unlatched” when it is desired to retract the sleeve and expose the hemostatic implant. Thus, the methods of the present invention will preferably further comprise unlatching the sleeve before retracting the sleeve. In a specific embodiment, the unlatching comprises distally advancing a key over the latch to effect the desired unlatching. As described above in connection with the apparatus of the present invention, an exemplary latch and key comprises a spring-like element which is secured over an exterior portion of the shaft. The spring-like element typically projects radially outward from the shaft when unconstrained. In this way, the spring-like latch element can engage the protective sleeve to prevent proximal retraction of the sleeve. The latch can be released by advancing a cylindrical or other key element distally over the shaft to depress the spring-like latch element. [0024] In a further preferred aspect of the method of the present invention, a proximal portion of the sleeve will be configured to lie proximal to, i.e., outside of, the tissue tract when the occlusion element is deployed in the blood vessel lumen. Usually, the key element will lie further proximal of the sleeve, permitting the user to manually deploy the key to unlock the latch and to further manually retract the protective sleeve by manually clasping an exposed portion of the sleeve and pulling it proximally from the tissue tract. Typically, the sleeve will have a length in the range from 2 cm to 30 cm, more typically from 5 cm to 15 cm. [0025] In a still further preferred aspect of the method, the hemostatic implant will be constrained to prevent it from being displaced proximally while the shaft is being introduced through the tissue tract. In particular, the backstop or other element may be fixed to the shaft in a location selected to engage the hemostatic implant or an extension thereof to prevent the implant from being displaced proximally, either as the shaft is being introduced or more likely as the protective sleeve is being proximally retracted over the implant. Usually, the backstop or other element will be slidably mounted over the shaft so that it may be held in place as the occlusion element is retracted past the hemostatic implant. [0026] In a specific aspect of the method of the present invention, radiopaque markers on or within the shaft or hemostatic implant are used to verify the location of implant prior to release. Inclusion of radiopaque markers on the delivery shaft is particularly useful when no radiopaque material is incorporated within the hemostatic implant. Preferably, there will be at least two distinct radiopaque bands, with one at each end of the implant. By observing the orientation of the two markers, the physician can determine whether the implant is properly aligned adjacent to the vascular penetration or has inadvertently advanced into a lumen of the blood vessel prior to deployment. In particular, by measuring or visually assessing the apparent distance between the bands when the device is being fluoroscopically imaged from an anterior aspect, the apparent distance between the bands will be longer if the hemostatic implant is within the blood vessel lumen than if it is within the tissue tract immediately above the blood vessel wall penetration. Such apparent differences in the positions of the two radiopaque marker bands results from the foreshortening of the vertical angle at the entry through the wall penetration into the blood vessel lumen. For example, if the tissue tract is disposed at a 45.degree. angle with respect to the horizontal orientation of the blood vessel lumen, in an anterior view, the marker bands will appear to be approximately 30% closer to each other than they would in the horizontal view when they are present in the blood vessel lumen. BRIEF DESCRIPTION OF THE DRAWINGS [0027] FIG. 1 illustrates an exemplary sealing apparatus constructed in accordance with the principles of the present invention, shown in section. [0028] FIG. 1A is a detailed view of a distal portion of the sealing apparatus of FIG. 1 , shown in partial section. [0029] FIG. 2 is a cross-sectional view of the sealing apparatus of FIG. 1 , shown with an expanded occlusion element. [0030] FIGS. 3-7 illustrate the further steps of deployment of the hemostatic implant from the apparatus of FIGS. 1 and 2 . [0031] FIGS. 8A-81 illustrate placement and deployment of the hemostatic implant using the apparatus of FIGS. 1 and 2 through a vascular sheath placed in a blood vessel. [0032] FIGS. 9A-9C illustrate a sealing apparatus in accordance with the present invention having a protective sleeve including an outer sleeve and an inner release sheath. [0033] FIGS. 10A-10C illustrate a sealing apparatus in accordance with the present invention having a key latch mechanism which engages the protective sleeve and may be used to proximally withdraw the sleeve to deploy the hemostatic implant. [0034] FIGS. 11A and 11B illustrate a hemostatic implant which is coaxially disposed about the shaft of the deployment apparatus of the present invention. [0035] FIGS. 12A and 12B illustrate the hemostatic implant which is laterally disposed relative to the shaft of the deployment mechanism. [0036] FIGS. 13A and 13B illustrate how aligned radiopaque markers may be utilized to determine that the hemostatic implant is properly located prior to deployment. [0037] FIGS. 14A and 14B illustrate how such radiopaque markers would appear when the hemostatic implant is improperly positioned prior to deployment. [0038] FIGS. 15A-15F illustrate an alternative hemostatic implant protocol. DETAILED DESCRIPTION OF THE INVENTION [0039] Referring to FIGS. 1 and 1A , an exemplary sealing apparatus 10 constructed in accordance with the principles of the present invention comprises a shaft assembly 70 including an outer tube 71 and an inner rod 76 . An expansible occlusion element 90 is mounted at a distal end (to the right in FIGS. 1 and 1A ) of the shaft assembly 70 and includes a radially expansible mesh 74 covered by an elastomeric membrane 96 . A handle assembly 78 is attached to a proximal end of the shaft assembly 70 and is operatively attached to both the outer tube 71 and inner rod 76 so that the inner rod can be axially advanced and retracted relative to the outer tube. The inner rod 76 and outer tube 71 are coupled together at the distal tip of the sealing apparatus 10 by a plug 77 and a proximal anchor 75 , respectively. The occlusion element 90 is held between the plug 77 and the proximal anchor 75 so that axial retraction of the rod in the proximal direction (to the left as shown in FIGS. 1 and 1A ) foreshortens the occlusion element 90 , causing the occlusion element to expand radially, as shown for example in FIG. 2 . [0040] Axial advancement and retraction of the rod 76 relative to the outer tube 71 is effected using the handle assembly 78 . The handle assembly 78 includes a cylindrical body 103 attached to the proximal end of the outer tube 71 by a bushing 104 so that the body 103 will remain fixed relative to the outer tube as the inner rod 76 is retracted and advanced. The inner rod is retracted and advanced by a slide assembly 101 which includes a short tube 110 fixedly attached to an endcap 111 and a slide cylinder 109 . The inner rod 76 is secured by tube element 107 which carries locking element 106 and bearing elements 108 and 109 . Bearing element 109 is attached to proximal grip 101 and the assembly of the grip 101 and tube element 107 can slide freely within the interior of the cylindrical body 103 so that the rod 76 may be proximally retracted relative to the body 103 and outer tube 71 , as shown in FIG. 2 . Once the expansible occlusion element 90 has been radially expanded, the rod 76 will remain retracted and is held in place by locking element 106 which is pulled over a detent 105 , again as shown in FIG. 2 . An alignment bushing 108 is provided in the interior of the cylindrical body 103 to maintain alignment of the slide assembly 101 relative to the cylindrical body. [0041] The sealing apparatus of the present invention may optionally include a tensioning mechanism 80 which includes a coil spring 86 , a gripping element 85 , and a coupling element 87 . The tensioning mechanism 80 may be selectively positioned along the length of shaft assembly 70 , and will provide a tension determined by the constant of coil spring 86 to hold the expanded occlusion element 74 against the vascular penetration, as described in more detail in copending, commonly-owned application Ser. No. 10/974,008, (Attorney Docket No. 021872-002010US), the full disclosure of which is incorporated herein by reference. As described thus far, the construction and use of the sealing apparatus including shaft assembly 70 , handle assembly 78 , tensioning mechanism 80 , and expansible occlusion element 90 are generally the same as illustrated in copending application Ser. No. 10/974,008. The present invention is directed at modifications and improvements to the earlier device for delivering a hemostatic implant into the tissue tract generally above the vascular wall penetration, as will be described in more detail below. [0042] As best seen in FIG. 1A , hemostatic implant 121 , which will typically be a biodegradable polymer as described in more detail above, is carried coaxially or in parallel over the outer tube 71 near the distal end thereof proximal to the expansible occlusion element 90 . While the hemostatic implant 121 is shown to be positioned coaxially over outer tube 71 in FIG. 1A , it will often be desirable to modify or reposition the implant in order to facilitate release from the sealing apparatus after the implant has been deployed. More simply, the hemostatic implant could be axially split to allow it to partially open after it is hydrated and facilitate passage of the collapsed occlusion element 74 as the sealing apparatus is being withdrawn. Alternatively, the hemostatic implant may be reconfigured and carried laterally (i.e., to one side of) with respect to the shaft of the sealing apparatus, as described in more detail hereinafter with respect to FIGS. 9A and 9C . The hemostatic implant 121 could alternatively be carried on the inner surface of a protective sleeve 123 which is slidably carried over the outer tube 71 . The protective sleeve 123 slides over a backstop 127 which is slidably mounted over the outer tube 71 and which is prevented from moving proximally by stop member 125 which is fixed to the outer surface of the outer tube. Backstop 127 has a distal end 128 which engages a proximal end of the hemostatic implant 121 . Thus, by proximally retracting the protective sleeve 123 , the hemostatic implant 121 can be exposed to the tissue tract and released from the sealing apparatus. [0043] Accidental axial retraction of the protective sleeve 123 is prevented by a latch mechanism including a latch element 120 and a key 126 ( FIGS. 1 and 2 ). The latch element 120 is typically a spring-loaded component, for example a conical spring having a narrow diameter end attached to the outer tube 71 and a flared or larger diameter end 129 which engages a stop ring 124 formed on the inner surface of the protective sleeve 123 . So long as the flared end 129 of the latch element 120 remains in its flared or open configuration, as illustrated in FIG. 1A , accidental proximal retraction of the sleeve is prevented. It is further noted that the stop ring 124 engages stop member 125 of the backstop 127 preventing accidental distal movement of the protective sleeve 123 . Thus, when the sealing apparatus 10 is introduced to a tissue tract, as described in more detail below, movement of the protective sleeve 123 in either the distal or proximal direction is inhibited. [0044] To allow selective proximal retraction of the protective sleeve 123 , the key 126 ( FIGS. 1 and 2 ) may be axially advanced to engage the latching element 120 , as illustrated in FIG. 3 . The key 126 fits inside of the protective sleeve 123 and depresses or radially contracts the latch element 120 so that it fits within the interior circumference of the stop ring 124 , thus allowing proximal retraction of the protective sleeve 123 , as shown in FIG. 4 . [0045] Once the key 126 has engaged and constrained the latch element 120 , as shown in FIG. 3 , the protective sleeve 123 may be proximally withdrawn past the hemostatic implant 121 and the backstop 127 , as shown in FIG. 4 . Thus, the hemostatic implant 121 will be released from constraint and exposed to the environment in the tissue tract. The environment in the tissue tract will include blood and other body fluids which can hydrate the hemostatic implant 121 , causing swelling as shown in FIG. 4 . The swelling will continue, as shown in FIG. 5 , and the radially expanded occlusion element 90 can be collapsed using the handle assembly, as shown in FIG. 5 . The collapsed occlusion element 90 can then be proximally withdrawn into distal receptacle 128 of the backstop assembly 127 , as shown in FIG. 6 (where an annular space may be provided to accommodate the occlusion element). When the occlusion element has been fully withdrawn within the backstop 127 , the hemostatic implant is completely released, as shown in FIG. 6 , and the remaining portions of the sealing apparatus can be pulled away from the hemostatic implant, as shown in FIG. 7 . [0046] Referring now to FIGS. 8A-81 , deployment and use of the sealing apparatus 10 of the present invention through an introducer sheath 40 will be described in more detail. Introducer sheath 40 will typically be in place within a blood vessel lumen 41 passing from the skin surface 46 through tissue 45 in a tissue tract. A vascular wall penetration 42 will thus be present in the vascular wall 43 , all as shown in FIG. 8A . The sealing apparatus 10 is then introduced through the access sheath 40 so that the expansible occlusion element 90 passes out through the distal end of the sheath, as shown in FIG. 8B . Handle assembly 78 will remain outside of the sheath and accessible to the user so that the slide assembly 101 may be pulled relative to the cylindrical body 103 to radially expand the occlusion element 90 , as shown in FIG. 8C . The vascular access sheath 40 may then be withdrawn over the exterior of the sealing apparatus 10 while the sealing apparatus is simultaneously withdrawn to seat the expanded occlusion element 90 against the vascular penetration 42 , as shown in FIG. 8D . [0047] At that point, the protective sleeve 123 and key 126 become exposed and available to the user for manipulation. The key may then be distally advanced over the outer tube 71 so that the key engages and depresses the latch 120 ( FIG. 1A ) as illustrated in FIG. 8E . The key 126 and protective sleeve 123 may then be manually pulled in a proximal direction over the outer tube 71 to release the hemostatic implant 121 , as shown in FIG. 8F . The expandable element 90 may then be collapsed, as shown in FIG. 8G , and the collapsed element withdrawn into the receptacle 128 of the backstop 127 of the sealing apparatus, as shown in FIG. 8H . The entire sealing apparatus 10 , except for the hemostatic implant 121 , may then be withdrawn from the tissue tract, leaving the hemostatic implant 121 in place over the now closed vascular wall penetration, as shown in FIG. 81 . The hemostatic implant, which may optionally carry the anti-proliferative, coagulation promoting, and/or radiopaque substances described above, will remain in place inhibiting bleeding and allowing the vascular wall penetration to heal. Over time, the hemostatic implant 121 will preferably biodegrade, leaving a healed tissue tract and vascular wall penetration which are usually suitable for re-entry at a subsequent time. [0048] Referring now to FIGS. 9A-9C , a protective sleeve 123 ′ comprises an outer sleeve 150 and an inner release sheath 152 . The outer sleeve 150 and inner release sheath 152 are separately retractable so that the outer sleeve may first be retracted relative to the hemostatic implant 121 ( FIG. 9B ) while the inner release sheath initially remains over the implant. The release sheath 152 will thus provide an anti-friction interface so that the outer sleeve 150 slides over the implant 121 with reduced sticking The inner release sheath 152 is preferably formed from a relatively lubricious or slippery material and will preferably include an axial opening or slit 158 which permits the distal portion thereof to partially open after the outer sleeve 150 has been retracted, as shown in FIG. 9B . Once the outer sleeve 150 has been retracted to relieve constraint over the hemostatic implant, the inner sleeve may then be retracted to completely release the hemostatic implant, as shown in FIG. 9C . Conveniently, the outer sleeve 150 may be coupled to the inner release sheath 152 so that proximal retraction of the outer sleeve will automatically retract the inner release sheath at the proper point in travel. For example, a cavity or channel 154 may be formed in an inner surface of the outer sleeve 150 and a ring or other engaging element 156 may be formed on the outer surface of the inner release sheath 152 . Initially, the ring 156 will be positioned at the proximal end of the cavity or channel 154 , as shown in FIG. 9A . After the outer sleeve 150 has been retracted so that it no longer lies over the implant 121 , the ring may then engage a distal end of the cavity or channel 154 , as shown in FIG. 9B , and engage the ring 156 , allowing the outer sleeve to then pull the inner sleeve proximally, as shown in FIG. 9C , to fully release the hemostatic implant 121 . [0049] Referring now to FIGS. 10A-10C , it is also possible to selectively couple the key 126 ′ to a protective sleeve 123 ′. The key 126 ′ has a coupling element, such as plurality of proximally disposed barbs 160 at its distal end. The key 126 ′ may be advanced into the protective sleeve 123 ′ where a distal end 162 of the key 126 ′ engages latching element 120 ′ on the outer tube 71 ′. Latching mechanism 120 ′ may conveniently comprise a plurality of barbs so that advancement of the key 123 ′ radially closes the barbs allowing the protective sleeve 123 ′ to be proximally retracted relative to the tube 71 ′. Once the key 126 ′ is fully distally advanced, as shown in FIG. 10B , the proximally disposed barbs 160 will engage an inner lip 164 at the proximal end of the protective sleeve 123 ′. Thus, as the key 126 ′ is proximally retracted, as shown in FIG. 10C , the key will pull the protective sleeve 123 ′ in a proximal direction, thus exposing the implant 121 . [0050] A further aspect of the present invention is illustrated in FIGS. 10A and 10B . Radiopaque marker bands 170 and 172 may be provided at the proximal and distal ends of the implant 121 , respectively. Usually, these bands will be disposed on the outer tube 71 ′, but they could also be disposed on or incorporated within the hemostatic implant 121 . In either case, they are useful to evaluate positioning of the hemostatic implant prior to deployment, as described in more detail below in FIGS. 13A, 13B, 14A, and 14B . [0051] Referring now to FIGS. 11A and 11B , the hemostatic implant 121 may be disposed coaxially over the outer tube 71 and in a rod 76 . By proximally retracting the protective sleeve 123 , the implant 121 is released and can hydrate as shown in FIG. 11B . As described previously, however, it will still be necessary to withdraw the outer tube 71 as well as the collapsed occlusion element 90 past the hemostatic implant 121 . When the hemostatic implant 121 fully circumscribes the outer tube 71 , however, both the tube 71 and the collapsed occlusion element 90 can tend to dislodge the implant within the tissue tract. [0052] Therefore, in some instances, it will be desirable to modify the geometry of the implant to facilitate withdrawal of the outer tube and the collapsed occlusion element. For example, as shown in FIGS. 12A and 12B , hemostatic implant 121 ′ can be formed with a crescent-shaped cross-section so that it does not fully circumscribe the outer tube 71 which carries it. By laterally displacing the outer tube 71 and inner rod 76 within the protective sleeve 123 , as shown in FIG. 12A , the volume of the hemostatic implant 121 will be generally the same as that shown in FIG. 11A . When the protective sleeve 123 is withdrawn, however, as shown in FIG. 12B , the hemostatic implant 121 will hydrate and expand laterally on one side of the outer tube 71 , as shown in FIG. 12B . By disposing the outer tube 71 and collapsed occlusive element 90 to one side of the implant, it is much easier to withdraw the apparatus and collapsed occlusion member past the implant without dislodging the implant within the tissue track. [0053] Referring now to FIGS. 13A and 13B , the radiopaque markers 170 and 172 can be used to determine whether the hemostatic implant 121 is oriented properly prior to deployment. For simplicity, the protective sleeve and other components of the deployment system are not shown in FIGS. 13A and 13B (or in 14 A and 14 B as described below). The radiopaque markers 170 and 172 may be formed as part of the deployment instrument, for example being placed on outer tube 71 , and/or may be formed as part of the hemostatic implant 121 . In either case, when the deployment apparatus is properly oriented as shown in FIG. 13A , the radiopaque markers 170 and 172 will appear to be stacked generally vertically when viewed in an anterior view, as shown in FIG. 13B . In contrast, if the apparatus has been improperly deployed so that the hemostatic implant has been advanced into the vessel lumen past the tissue tract TT as shown in FIG. 14A , then the radiopaque markers 170 and 172 will be spaced apart in the anterior view as shown in FIG. 14B . As these views will be readily distinguishable by the physician using conventional fluoroscopy, the radiopaque markers provide a convenient and reliable indicator of when it is acceptable to deploy the hemostatic implant. [0054] Referring now to FIGS. 15A through 15F , a method for hemostasis of a puncture site in a body lumen employing the device 270 of FIG. 1 is illustrated. FIG. 15A depicts an existing introducer sheath 240 advanced through an opening in a skin surface 246 , tissue tract in fascia 245 and vessel wall 243 and seated in a vessel lumen 241 at the completion of a catheterization procedure. Device 270 is then inserted through the hub of the sheath 240 and is advanced until the expansible member 274 is outside the sheath 240 and in the vessel lumen 241 , as shown in FIG. 15B . This positioning may be indicated by a mark or feature on the catheter 271 or the handle assembly 278 . [0055] As shown in FIG. 15C , the expansible member 274 is then deployed by operation of the handle assembly 278 . The sheath 240 is then slowly pulled out of the body, placing the expansible member 274 against the inner wall of the vessel 243 at the puncture site 242 . As the sheath 240 is removed, the grip member 285 which is slidably disposed over the catheter shaft 271 and the handle assembly 278 are revealed. Sheath 240 is then discarded, leaving deployed expansible member 274 seated at the puncture site 242 and the bio-chemical chamber/region 351 in the tissue tract 247 as shown in FIG. 15D . If the device is equipped with the safety seal 355 as in device 270 , then the safety seal 355 is removed by pulling the tab 356 proximally along the catheter shaft. [0056] Referring now to FIG. 15E , once safety seal 355 is removed, the grip element 285 is grabbed and pulled in a proximal direction. Grip 285 is moved proximally to provide adequate amount of tension to the deployed expansible member 274 to achieve hemostasis. Typically, the amount of tension applied to the expansible member 274 is in the range of 0.5 ounces to 30 ounces. In particular, proximal movement of grip 285 causes simultaneous elongation of the tensioning coil 286 , causing the expansible member to locate and temporarily close the puncture site 242 , and displacement of the bio-chemical seal 353 , exposing the bio-chemical agent 352 to the surrounding tissue at a predetermined distance from the puncture site. The elongated position of coil 86 is maintained by application of a small external clip 250 to the catheter and seated against the surface of the skin 246 , as shown in FIG. 15E . Device 270 is left in this position for a period of time to allow the bio-chemical agent 352 to reconstitute with the fluids in the tissue tract 247 , generating coagulum. Clip 250 is then removed and the expansible member 274 is collapsed by manipulation of the handle assembly 278 . Device 270 is then removed, leaving the active bio-chemical agents 352 and the coagulum in the tract 247 and adjacent the vessel puncture site 242 , as shown in FIG. 15F . Additional finger pressure at the puncture site may be required to allow the coagulum to seal the small hole left in the vessel wall after removal of the device. [0057] While the above is a complete description of the preferred embodiments of the invention, various alternatives, modifications, and equivalents may be used. Therefore, the above description should not be taken as limiting the scope of the invention which is defined by the appended claims.

Apparatus for sealing a vascular wall penetration disposed at the end of the tissue tract comprises a shaft, an occlusion element, a hemostatic implant, and a protective sleeve. The apparatus is deployed through the tissue tract with the occlusion element temporarily occluding the vascular wall penetration and inhibiting backbleeding therethrough. The hemostatic implant, which will typically be a biodegradable polymer such as collagen carrying an anti-proliferative agent or coagulation promoter, will then be deployed from the sealing apparatus and left in place to enhance closure of the vascular wall penetration with minimum scarring. The implant may be radiopaque to allow observation before release.

CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims the benefit of U.S. Provisional Application No. 61/606,580, filed Mar. 5, 2012. BACKGROUND [0002] Light emitting diodes (LEDs) generate light in zones so small (a few mm across) that it is a perennial challenge to spread their flux uniformly over a large target zone, especially one that is much wider than its distance from the LED. So-called short-throw lighting, of close targets, is the polar opposite of spot lighting, which aims at distant targets. Just as LEDs by themselves cannot produce a spotlight beam, and so need collimating lenses, they are equally unsuitable for wide-angle illumination as well, and so need illumination lenses to do the job. [0003] A prime example of short throw lighting is the optical lens for the back light unit (BLU) for a direct-view liquid crystal display (LCD) TVs. Here the overall thickness of the BLU is usually 26 mm or less and the inter-distance between LEDs is about 200 mm. Prior art for LCD backlighting consisted of fluorescent tubes arrayed around the edge of a transparent waveguide, that inject their light into the waveguide, which performs the actual backlighting by uniform ejection. While fluorescent tubes are necessarily on the backlight perimeter due to their thickness, light-emitting diodes are so much smaller that they can be placed directly behind the LCD display, (so called “direct-view backlight”), but their punctate nature makes uniformity more difficult, prompting a wide range of prior art over the last twenty years. Not all of this art, however, was suitable for ultra-thin displays. [0004] Another striking application with nearly as restrictive an aspect ratio is that of reach-in refrigerator cabinets. Commercial refrigerator cabinets for retail trade commonly have glass doors with lighting means installed behind the door hinging posts, which in the trade are called mullions. Until recent times, tubular fluorescent lamps have been the only means of shelf lighting, in spite of how cold conditions negatively affect their luminosity and lifetime. Also, fluorescent lamps produce a very non-uniform lighting pattern on the cabinet shelves. Light-emitting diodes, however, are favored by cold conditions and are much smaller than fluorescent tubes, which allow for illumination lenses to be employed to provide a much more uniform pattern than fluorescent tubes ever could. Because fluorescent tubes radiate in all directions instead of just upon the shelves, much of their light is wasted. With the proper illumination lenses, however, LEDs can be much more efficient, allowing lower power levels than fluorescent tubes, in spite of the latter's good efficacy. [0005] The prior art of LED illumination lenses can be classified into three groups, according to how many LEDs are used: (1) Extruded linear lenses with a line of small closely spaced LEDs, particularly U.S. Pat. Nos. 7,273,299 and 7,731,395, both by these Inventors, as well as References therein. (2) A line of a dozen or more circularly symmetric illumination lenses, such as those commercially available from the Efficient Light Corporation. (3) A line of a half-dozen (or fewer) free-form illumination lenses with rectangular patterns, such as U.S. Pat. No. 7,674,019 by these Inventors. [0009] The first two approaches necessarily require many LEDs in order to achieve reasonable uniformity, but recent trends in LEDs have produced such high luminosity that fewer LEDs are needed, allowing significant power savings. This is the advantage of the last approach, but free-form lenses generating rectangular patterns have proved difficult to produce, via injection molding, with sufficient figural accuracy for their overlaps to be caustic-free. (Caustics are conspicuous small regions of elevated illuminance.) [0010] What is needed instead is a circularly symmetric illumination lens that can be used in small numbers (such as five or six per mullion) and still attain uniformity, because the individual patterns are such that those few will add up to caustic-free uniformity. The objective of this Invention is to provide a lens with a circular illumination pattern that multiples of which will add up to uniformity across a rectangle. It is a further objective to attain a smaller lens size than the above mentioned approaches, leading to device compactness that results in lower manufacturing cost. The smaller lens size can be achieved by a specific tailoring of its individual illumination pattern. This pattern is an optimal annulus with a specific fall-off that enables the twelve patterns to add up to uniformity between the two illuminating mullions upon which each row of six illuminators are mounted. This fall-off at the most oblique directions is important, because this is what determines overall lens size. The alternative approaches are: (1) Each mullion illuminates 100% to mid-shelf and zero beyond, which leads to the aforementioned caustics; (2) Each mullion contributes 50% at the mid-point, falling off beyond it. The latter is the approach of this Invention, and has proven highly successful. [0011] The prior art is even more challenged, moreover, when fewer LEDs are needed due to ongoing year-over-year improvements in LED flux output. After all, backlight thickness is actually relative to the inter-LED spacing, not to the overall width of the entire backlight. For example, in a 1″ thick LCD backlight with 4″ spacing between LEDs, the lens task is proportionally similar to the abovementioned refrigerator cabinet. Because of the smaller size of an LCD as compared to a 2.5 by 5 foot refrigerator door, lower-power LEDs with smaller emission area will be used, typically a Top-LED configuration with no dome-like silicone lens. [0012] Regarding the prior art patents which have taught non-specific design methods for addressing this problem are: US 2006/0138437, U.S. Pat. No. 7,348,723, U.S. Pat. No. 7,445,370, U.S. Pat. Nos. 7,621,657 and 7,798,679 by Kokubo et al. shows the same cross-sectional lens profile as in FIG. 15A of U.S. Pat. No. 7,618,162 by Parkyn and Pelka, while failing to reference it. U.S. Pat. No. 7,798,679 furthermore contains only generically vague descriptions of that lens profile, and worse yet has no specific method of distinguishing the vast number of significantly different shapes fitting its vague verbiage, its many repetitively generic paragraphs notwithstanding. Experience has shown that illumination lenses are unforgiving of small shape errors, such as result from unskilled injection molding or subtle design flaws. Very small changes in local slope of a lens can result in highly visible illumination artifacts sufficient to ruin an attempt at a product. Therefore such generic descriptions are insufficient for practical use, because even the most erroneous and ill-performing lens fulfills them just as well as an accurate, high-performing lens. Thus U.S. Pat. No. 7,798,679 does not pertain to the preferred embodiments disclosed herein, because it never provides the specific, distinguishing shape-specifications whose precise details are so necessary for modern optical manufacturing. SUMMARY [0013] Commercial refrigerator display cabinets for retail sales have a range of distances from mullion to the front of the shelves, commonly from 3″ to 8″, with the smaller spacings becoming more prevalent as store owners seek to cram more and more product into their reach-in refrigerator cabinets. Fluorescent tubes have great difficulty with these tighter spacings, leading to an acceleration in the acceptance of LED lighting technology. Even though fluorescent tubes have efficacy comparable to current LEDs, their large size and omnidirectional emission hamper their efficiency, making it difficult to adequately illuminate the mid-shelf region. Early reach-in refrigerator LED illuminators utilized a large number of low-flux LEDs, but continuing advances in luminosity enable far fewer LEDs to be used to produce the same illuminance. This places a premium on having illumination lenses that when arrayed will sum up to uniformity while also having the smallest possible size relative to the size of the LED. [0014] Disclosed herein are preferred embodiments that generate wide-angle illumination patterns suitable for short-throw lighting. Also disclosed is a general design method for generating their surface profiles, one based on nonimaging optics, specifically a new branch thereof, photometric nonimaging optics. This field applies the foundational nonimaging-optics idea of etendue in a new way, to analyze illumination patterns and classify them according to the difficulty of generating them, with difficulty defined as the minimum size lens required for a given size of the light source, in this case, the LED. OBJECTIVES [0015] It is the first objective to disclose numerically-specific lens configurations that in arrays will provide uniform illumination for a close planar target, especially in retail refrigeration displays and in thinnest-possible direct-view LCD backlights. [0016] It is the second objective to provide compensation for the illumination-pattern distortions caused by volume scattering and scattering due to Fresnel reflections, which together act as an additional, undiscriminating secondary light source. [0017] On fulfillment of the inventor's duty to go beyond superficial description, it is the third objective to disclose fully the design methods that generated the preferred embodiments disclosed herein, such that those skilled in the art of illumination optics could design further preferred embodiments for other illumination applications, in furtherance of the ultimate objective of the patent system that being to expand public knowledge. BRIEF DESCRIPTION OF THE DRAWINGS [0018] The above and other aspects, features and advantages will be apparent from the following more particular description thereof, presented in conjunction with the following drawings wherein: [0019] FIG. 1 shows how a rectangular door is illuminated by circular patterns. [0020] FIG. 2 shows a graph of an individual illumination pattern. [0021] FIG. 3 shows an end view of the door of FIG. 1 , with slant angles. [0022] FIG. 4 shows a graph of required source magnification. [0023] FIG. 5 shows a cross-section of an illumination lens and LED. [0024] FIG. 6A-6F show source-image rays from across the target. [0025] FIG. 7 shows how a rectangular door is illuminated by only 4 LEDs. [0026] FIG. 8 shows a cross-section of a further illumination lens and LED. [0027] FIG. 9 illustrates a mathematical description of volume scattering. [0028] FIG. 10 is a graph of illumination patterns. [0029] FIG. 11 sets up a 2D source-image method of profile generation. [0030] FIG. 12 shows said method of profile generation. [0031] FIGS. 13A and 13B show the 3D source-image method of profile generation. [0032] FIG. 14 shows a plano-convex lens-center, with defining rays. [0033] FIG. 15 shows a concave-concave lens-center, with defining rays. [0034] FIG. 16 shows a concave-plano lens-center, with defining rays. [0035] FIG. 17 shows the complete lens made from the lens-center of FIG. 14 . [0036] FIG. 18 shows the complete lens made from the lens-center of FIG. 15 . [0037] FIG. 19 shows the complete lens made from the lens-center of FIG. 16 . DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0038] A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description of the invention and accompanying drawings, which set forth illustrative embodiments in which principles of the invention are utilized. [0039] FIG. 1 shows rectangular outline 10 representing a typical refrigerator door that is 30″ wide and 60″ high, with other doors, not shown, to either side. Dashed rectangles 11 denote the mullions behind which the shelf lighting is mounted, typically at 3-6″ from the front of the illuminated shelves. This is much closer than the distance to the shelf center, denoted by centerline 12 . There are twelve illuminators 31 (six on either side), four of which are denoted by small circles 1 . Each illuminator 31 produces an illuminated circle with its peak on a ring denoted by solid circles 2 and its edge on dotted circles 3 . Here the circles 2 have radius of a quarter of the shelf width, or halfway to centerline 12 . The circles 3 , where illuminance has fallen to zero, are sized to meet the circles 2 from the opposite mullion. [0040] FIG. 2 shows graph 20 with abscissa 21 that is horizontally scaled the same as FIG. 1 above it. Ordinate 22 is scaled from 0 to 1, denoting the ideal illuminance I(x), as graphed by curve 23 , generated on the shelves by an illuminator 31 under the mullion. This illumination function is relative to the maximum on circle 2 , which has radius x M . It falls off to zero at radius x E . This gradually falling illuminance is paired with the gradually ascending one of the illuminator 31 on the opposite side of the door, so the two patterns add up to constant illuminance along the line 4 of FIG. 1 . [0041] An actual injection-molded plastic lens will exhibit volume scattering within its material, making the lens itself an emitter rather than a transmitter. This volume scattered light will be strongest just over the lens. The central dip in the pattern 23 , shown in FIG. 2 to be at the ¾ level, compensates for this extra volume-scattered light, so that the total pattern (direct plus scattered) is flat within circle 2 . This effect becomes more pronounced with the larger lenses discussed below. [0042] Another advantage of this type of gradually falling-off pattern is that any point on centerline 12 is lit by several illuminators 31 on each mullion, assuring good uniformity. The dotted curve 24 shows the illumination pattern of an LED alone. It is obviously incapable of adding up to satisfactory illumination, let alone uniform, hence the need for an illumination lens 51 to spread this light out properly. [0043] FIG. 3 shows an end view of shelf-front rectangle 30 identical to that of FIG. 1 . Illuminators 31 are located as shown by small rectangles 31 . This addresses the difficulty of lighting from so close to the shelf, in this case at a distance of z T =4″. FIG. 3 shows the distances x m =15″ and x E =22.5″, respectively, to centerline 33 and edge-line 34 , at which the pattern of illuminator 31 has reached zero illuminance. These distances correspond to off-axis angles from the normal given by [0000] γ m =tan −1 ( x m /z T )=tan −1 (15/4)=75° γ E =tan −1 ( x E /z T )=tan −1 (22.5/4)=80° [0000] These large slant-angles drive the lens design, requiring considerable lateral magnification of the source by the lens. At low slant-angles, in contrast, the lens must demagnify. [0044] This concept of magnification and demagnification can be made more explicit via etendue considerations. The source-etendue is that of a chip of area A S =2.1 mm 2 , immersed in a dome of refractive index n=1.45: [0000] E S =πn 2 A S sin 2 θ=14 mm 2 [0000] Here θ is 90° for a Lambertian source of which an LED is a very good approximation°. [0045] An illumination lens 51 basically redistributes this etendue over the target, which is much larger than the chip. In the case of the illumination pattern in FIG. 2 , the target etendue relates to the area A T of the 45″ illumination circle of FIG. 1 , as weighted by the relative illumination function 23 of FIG. 2 . This simple model of an actual illumination pattern has a central dip to illuminance I 0 , a rise to unity at x=x M , and a linear falloff to zero at x=x E . This is mathematically expressed as [0000] I ( x )= I 0 +x (1 −I 0 )/ x M x≦x M [0000] I ( x )=( x E −x )/( x E −x M ) x M ≦x≦x E [0000] Then the target etendue is given by an easily solved integral: [0000] E T = π   sin 2  θ T  ∫ 0 x   e  2  π   x   I  ( x )   x = 2  π 2  sin 2  θ T  ( [ I 0  x 2 2 + ( 1 - I 0 )  x 3 3   x M ] 0 x M + [ x E 2  ( x E - x M )  x 2 - x 3 3  ( x E - x M ) ] x M x E )  E T = sin 2  θ T  1.47   square   meters [0000] Here θ T is the half angle of a narrow-angle collimated beam with the same etendue as the source, so that [0000] sin 2 θ T ˜1 E− 5 θ T =±0.18° [0000] At the center of the lens this is reduced by ¾, to ±0.13°. This can be contrasted with the angular subtense of the source alone, as seen from directly above it on the shelf, at distance z T as shown in FIG. 3 : [0000] tan 2 θ S =n 2 A C /4 z T 2 θ S =±0.61° [0000] Thus the central demagnification of the lens needs to be 1:4.5, dictating that the central part of the lens be concave, in order to act as an expander with negative focal length. This can be attained on a continuum of concavity bounded by a flat-topped outer surface with a highly curved inside surface or a flat-topped inner surface with the outer surface highly curved. That of FIG. 5 lies between these extremes. [0046] As shown in FIG. 3 , a high slant angle γ means that to achieve uniform illumination the source image made by the lens must be correspondingly larger than for normal incidence, by a factor of 1/cos γ. The source itself will be foreshortened by a slant factor of cos γ, as well as looking smaller and smaller by being viewed from farther away, by a further factor of cos 2 γ. Thus the required lens magnification is [0000] M  ( γ ) = 1 4.5   cos 4  γ [0000] Note that magnification rises from ¼ on-axis to unity at an off-axis angle given by [0000] γ  ( M ) = cos - 1  1 4.5   M 4 γ  ( 1 ) = 47  ° [0047] These angles dilute the illuminance by a cosine-cubed factor, so that the farther out light must be thrown, the more intense must be the lens output. Considering that the LED source has a cosine fall-off of its own, the total source magnification required is the well-known cos −4 factor, amounting to 223 at 75° 1100 at 80° respectively. Here lies the advantage of the fall-off in the illumination pattern of FIG. 2 , since these deleterious factors are reduced accordingly. [0048] FIG. 4 shows graph 40 with abscissa 41 running from 0 to 80° in off-axis angle γ and ordinate 42 showing the source magnification M(γ) required for uniform illumination. Unit magnification is defined as a source image the same size as if there were no lens. What this magnification means is that the illumination lens 51 of the present invention must produce an image of the glowing source, as seen from the shelf, that is much bigger than the Lambertian LED source without any lens. For uniformly illuminating a 4″ shelf-distance, curve 43 shows that the required magnification peaks at 77.5°, while lower curve 44 is for the much easier case of a 6″ shelf distance, peaking at 71°. This required image-size distribution is the rationale for the configuration of the present invention. [0049] FIG. 5 is a cross-section of illuminator 31 , comprising illumination lens 51 , bounded by an upper surface 46 comprising a central spherical dimple with arc 52 as its profile and a surrounding toroid with elliptical arc 53 as its profile, and also bounded by a lower surface 48 comprising a central cavity 54 with bell-shaped profile 54 and surrounding it an optically inactive cone 55 joining the upper surface 46 , with straight-line profile and pegs 56 going into circuit board 57 . Illuminator 31 further comprises LED package 58 with emissive chip 58 C immersed in transparent hemispheric dome 58 D. The term ‘toroid’ distinguishes from the conventional term ‘torus’, which solely covers the case of zero tilt angle. The highly oblique lighting setup of refrigerator-cabinet shelf-fronts involves tilting the torus so that the lensing effect of the elliptical arc 53 points toward the center of the shelf. [0050] Arc 52 of FIG. 5 extends to tilt angle τ, which in this case is 17°, its importance being that it is the tilt angle of major axis 53 A of elliptical arc 53 . Its minor axis 53 B lines up with the radius at the edge of arc 52 , ensuring profile-alignment with equal surface tangency. There are three free parameters which define a particular outer surface of illumination lens 51 , as intended for different shelf distances. The first is the radius of arc 52 , which controls the amount of de-magnification by the central portion of illumination lens 51 . The second is the tilt angle τ, which defines the orientation of elliptical arc 53 , namely towards the shelf center of FIG. 1 . The third free parameter of the upper surface 46 is the ratio of the radius to the elliptical arc 53 at major axis 53 A to the radius to the elliptical arc 53 at minor axis 53 B, in this case 1.3:1, defining the above-discussed source magnification. Ray-fan 59 comprises central rays (i.e., originating from the center of chip 58 C) at 2° intervals of off-axis angle. The central ten rays designated by dotted arc 59 C, outbound from the centerline or central axis 59 , illustrate the diverging character of the center of lens 51 , which provide the central demagnification required for uniform illumination. The remaining rays are all sent at steep angles to the horizontal, providing the lateral source magnification of FIG. 4 . [0051] The central cavity 54 surrounding LED 58 has bell-shaped profile 54 defined by the standard aspheric formula for a parabola (i.e., conic constant of −1) with vertex at z v , vertex radius of curvature r c , 4 th -order coefficient d and 6 th -order coefficient e: [0000] z ( x )= z v +x/r c +dx 4 +ex 6 [0000] In order for profile 54 to arc downward rather than upward, the radius of curvature r c is negative. The aspheric coefficients provide an upward curl 49 at the bottom of the bell, to help with cutting off the illumination pattern. The particular preferred embodiment of FIG. 5 , with a cavity entrance-diameter set at 6.45 mm, is defined by: [0000] z v =6 mm r c =−1.69 mm d=− 0.05215 e= 0.003034 [0000] This profile only needs minor modification to be suitable for preferred embodiments illuminating other shelf distances. [0052] FIG. 6A through 6F shows illumination lens 51 and LED chip 61 . In FIG. 6A , rays 62 come from points on the shelf at the indicated x coordinates of 0, 2″, and 4″ laterally from the lens. Each bundle is just wide enough that its rays end at the edges of chip 61 , which is the definition of a source image. Each bundle is narrower than chip 61 would appear by itself, in accordance with the previously discussed demagnification. The central portion of lens 60 that is traversed by rays 62 can be seen to be a concave, diverging lens, as previously mentioned. [0053] FIG. 6B shows ray bundle 63 proceeding from the distance x M to the maximum of the illumination pattern in FIG. 2 . It is twice the width of those in FIG. 6A . [0054] FIG. 6C shows ray bundle 64 proceeding from the distance x m to the middle of the shelf, as shown in FIG. 2 . [0055] FIG. 6D shows ray bundle 65 proceeding from beyond mid shelf, at 18″. [0056] FIG. 6E shows ray bundle 66 proceeding from beyond mid shelf, at 20″, nearly filling the lens. This is the maximum source magnification this sized lens can handle. [0057] FIG. 6F shows ray bundle 67 proceeding from the edge of the illumination pattern, at x E =22″. Note that these rays miss chip 61 , indicating that there will be no light falling there, which is required by the pattern cutoff. [0058] The progression of FIG. 6A through 6F is the basis for the numerical generation of the upper and lower surface profiles of the lens, starting at the center and working outwards, as will be disclosed below. The results of this method can sometimes be closely approximated by the geometry of FIG. 5 . [0059] The illumination lens 51 of FIG. 5 has elliptical and aspheric-parabolic surfaces with shapes that are exactly replicable by anyone skilled in the art. In the illumination pattern of FIG. 2 , the central depression to ¾ the maximum value was empirically found to work with the lens array of FIG. 1 , with six lenses on each side. This lens is the first commercially available design enabling only six LEDs to be used, rather than the dozen or more of the prior art. More recently, however, even higher-power LEDs have become available that only require two per door, as FIG. 7 illustrates. [0060] FIG. 7 shows rectangular outline 70 representing a typical refrigerator door that is 30″ wide and 60″ high, with other doors, not shown, to either side. Dashed rectangles 71 denote the mullions behind which the shelf lighting is mounted, typically at 3-6″ from the front of the illuminated shelves. This is much closer than the distance to the shelf center, denoted by centerline 72 . There are four illuminators 31 (two on either side), denoted by small circles 73 . Each illuminator 31 produces an illuminated circle with its peak on a ring denoted by solid circles 74 and its edge on dotted circles 75 . Here the circles 74 have radius of about a fifth of the shelf width, or a third the way to centerline 72 . The circles 75 , where illuminance has fallen to zero, are sized to reach nearly all the way across the shelf. As in FIG. 1 , each pattern has the value ½ at centerline 72 , so two lenses add to unity. Also, at shelf center-point 76 the four patterns overlap, so at this distance each pattern must have the value ¼, and thus add to unity. This same configuration is applicable for LCD backlights comprising square-arrayed LEDs, merely on a smaller scale. This arrangement of precisely configured illumination lenses 51 is capable of generating uniformity satisfactory for LCD backlights. [0061] The LEDs used in the arrangement of FIG. 7 must be three times as powerful as those used for FIG. 1 . This greater flux has unwanted consequences of triply enhanced scattered light, strengthened even more by the greater size of the lenses used for FIG. 7 versus the smaller ones which would suffice for FIG. 1 . The illumination pattern of FIG. 2 has a central dip in order to compensate for the close spacing of the lenses. When scattering is significant, however, the scattered light can be strong enough to provide all the illumination near the lens. The upshot is that the illumination pattern shown in FIG. 2 would have nearly zero intensity on-axis. The resultant lens has a previously unseen feature: either or both surfaces have a central cusp 82 that leaves no direct light on the axis, resulting in a dark center for the pattern, in order to compensate for the scattered light. [0062] FIG. 8 is a cross-section of illuminator 31 , comprising circularly symmetric illumination lens 51 , bounded by an upper surface comprising a central cusp 82 formed by a surrounding toroid with tailored arc 83 as its profile. Lens 81 is also bounded by a lower surface comprising a central cavity 54 with tailored profile 84 preferably peaking at its tip, and surrounding it an optically inactive cone 55 joining the upper surface, with straight-line profile 85 and pegs 56 going into circuit board 87 . Illuminator 31 further comprises centrally located LED package 88 with emissive chip 88 C immersed in transparent hemispheric dome 88 D. [0063] The optically active profiles 83 and 84 of FIG. 8 are said to be tailored due to the specific numerical method of generating it from an illumination pattern analogous to that of FIG. 2 , but with little or no on-axis output. The reason for this is, as aforementioned, to compensate for real-world scattering from the lens. The profiles 83 and 84 only control light propagating directly from chip 83 C, through dome 83 D, and thence refracted to a final direction that ensures attainment of the required illumination pattern. This direct pattern will be added to the scattering pattern of indirect light, which thus needs to be determined first. [0064] FIG. 9 shows illumination lens 51 , identical to lens 81 of FIG. 8 , with other items thereof omitted for clarity. From LED chip 98 C issues ray bundle 92 , comprising a left ray (dash-dot line), a central ray (solid line), and a right ray (dashed line), issuing respectively from the left edge, center, and right edge of LED chip 98 C. Anywhere within lens 91 , these rays define the apparent size of chip 98 C and thus how much light is passing through a particular point. Any light scattered from such a point will be a fixed fraction of that propagating light. The closer to the LED the more light is present at any point, and the greater the amount scattered. This scattering gives the lens its own glow, separate from the brightness of the LED itself when directly viewed. [0065] Strictly speaking, scattering does not take place at a point but within a small test volume, shown as infinitesimal cube 93 in FIG. 9 , magnified for clarity. It is oriented along the propagation direction of ray bundle 92 . It has cross-section 93 A of area dA and propagation length dl, such that its volume is simply dV=dl dA. Within cube 93 can be seen the left, central, and right rays of bundle 92 , now switched sides. The right and left rays define solid angle Ω, indicating the apparent angular size of LED chip 98 C as seen from cube 93 within lens 91 . The greater this solid angle the more light will be going through cube 93 . LED chip 98 C has luminance L, specified in millions of candela per square meter. This is reduced when ray bundle 92 goes into lens 91 , due to less-than-unity transmittance τ caused by Fresnel reflections. Going into cube 93 the ray bundle 92 has intensity I given simply by I=τ L dA. The total flux F passing through cube 93 is then given, simply again, by F=IΩ. [0066] Volume scattering removes a fixed fraction of this intensity I per unit length of propagation, similar to absorption. Both are described by Beer's law: [0000] I ( l )= I (0) e −κl [0000] Here I(0) is the original intensity and I(l) is what remains after propagation by a distance l, while scattering coefficient κ has the dimension of inverse length. It can easily be determined by measuring the loss in chip luminance as seen through the lens along the path l of FIG. 9 . [0067] Returning to cube 93 of FIG. 9 , the ingoing intensity I is reduced by the small amount dI=e −κdl . This results in a flux decrement dF=dIΩ that is subtracted from F. Then the emission per unit volume is dF/dV. Integrating this over the entire optically active volume of lens 91 gives the total scattered light. FIG. 9 further shows observer 94 gazing along line of sight 95 , along which direct rays 97 give rise to scattering points 96 , summing into a lens glow that acts as a secondary light source surrounding the LED. [0068] These scattering phenomena are usually looked upon as disadvantageously parasitic, acting only to detract from optical performance. There is a new aspect to this, however, where some volume scattering would be beneficial. It arises in the subtle failings of current high-brightness LEDs, namely that of not delivering the same color in all directions. More specifically, many commercially available LEDs with multi-hundreds of lumens output, look much yellower when seen laterally than face-on. This is because of the longer path through the phosphor taken by light from the blue chip. [0069] Thick phosphors have uniform whiteness, or color temperature, in all directions, but they reduce luminance due to the white light being emitted from a much bigger area than that of the blue chip. Conformal coatings, however, are thin precisely in order to avoid enlarging the emitter, but they will therefore scatter light much less than a thick phosphor and therefore do much less color mixing. As a result, lateral light is much yellower (2000 degrees color temp) and the face-on light much bluer (7000 degrees) than the mean of all directions. As a result of this unfortunate side-effect of higher lumen output, the lenses disclosed herein will exhibit distinct yellowing of the lateral illumination, and a distinct bluing of the vertical illumination. [0070] The remedy for this inherent color defect is to use a small quantity of blue dye in the lens material. Since the yellow light goes through the thickest part of the lens, the dye will automatically have its strongest action precisely for the yellowest of the LEDs rays, those with larger slant angles. The dye embedded in the injection-molding material should have an absorption spectrum that only absorbs wavelengths longer than about 500 nm, the typical spectral crossover between the blue LED and the yellow phosphor. The exact concentration will be inversely proportional to lens size as well as to the absorption strength of the specific dye utilized. [0071] A further form of scattering arises from Fresnel reflections, aforementioned as reducing the luminance of rays as they are being refracted. FIG. 9 further shows first Fresnel-reflected ray 92 F 1 coming off the inside surface of lens 91 , then proceeding into the lens to be doubly reflected out of the lens 92 F 1 and onto the printed circuit board. This ray has strength of (1−τ) relative to the original ray 92 , where tau is the coefficient of transmission at the particular point where the ray impinges upon the exit face. Of similar strength is the other Fresnel-reflected ray, 92 F 2 , which proceeds from the outer surface to the bottom of the lens. These two rays are illustrative of the general problem of stray light going where it isn't wanted. Unlike the volume scattering at points 96 , these Fresnel-reflected rays can travel afar to produce very displeasing artifacts and greatly destroy the uniformity of the optical system. It has been well-known for many decades of optical engineering that the easiest way to deal with this is to institute surface scattering or absorption of these stray rays. Since the flat conical bottom surface 91 C of lens 91 intercepts most of these stray Fresnel reflections, the tried-and-true traditional solution is simply to roughen the corresponding mold surface so that the Fresnel light is dissipated to become part of the above-described volume scattering. At the termination of ray 92 F 2 can be seen the scattered rays, some of which illuminate the top of substrate or printed circuit board (PCB) 99 , which of course could also be scattered by using a white diffuse white paint, say on the PCB. Another method that leads to some loss in overall optical efficiency of the system is to simply paint the bottom of the lens or the PCB with a highly absorbing black paint. This method has been found to produce excellent uniformity by these inventors for the illumination on LCD screens or for the reach-in refrigeration application, where really good uniformity on the illuminated packages has been produced. [0072] FIG. 10 shows graph 100 with abscissa 101 denoting distance in millimeters from the center of the lens of FIG. 9 and ordinate 102 denoting illuminance relative to the pattern maximum (in order to generalize to any illumination level). Dashed curve 103 is the ideal illumination pattern desired for the configuration of FIG. 7 , given an inter-lens spacing of 125 mm and a target distance of 23 mm. These dimensions represent a backlight application, where the LEDs are arrayed within a white-painted box, and the target is a diffuser screen, with a liquid-crystal display (LCD) just above it. Increased LED luminosity mandates fewer LEDs, to save on cost, while aesthetics push for a thinner backlight. These two factors comprise a design-pressure towards very short-throw lighting. [0073] The ‘conical pattern’ of curve 103 and its converse (not shown) from an illuminator 31 at 125 mm, will add to unity, which assures uniform illumination. Dash-dot curve 104 depicts the combined parasitic illuminance on that target plane caused by the above-discussed volume and surface scattering from a lens at x=0. This curve is basically the cosine 4 of the off-axis angle to a point on the target. Solid curve 105 is the normalized difference between the other two curves, representing the pattern that when scaled will add to curve 104 to get a total illuminance following curve 103 . In this case the scattered light of curve 104 is strong enough to deliver 100% of the required illuminance just above the lens. In such a case the central cusp 82 of FIG. 8 will ensure that the central illuminance is zero when only counting direct light that is delivered through the lens. [0074] The illumination pattern represented by curve 105 of FIG. 10 can be used to numerically generate the inner and outer profiles of the lens 81 of FIG. 8 , utilizing rays from the right and left edges of the source. Dotted curve 106 of FIG. 10 graphs the relative size of the source image height (as shown in FIG. 6A-F ) required by the illuminance pattern of curve 105 . This height function is directly used to generate the lens profiles. [0075] FIG. 11 shows LED 110 and illumination lens 51 , of 20 mm diameter, sending right ray 112 and left ray 113 to point 114 , which has coordinate x on planar target 115 , located 23 mm above LED 110 . Right ray 112 hits point 114 at slant angle γ, and left ray 113 at slant angle γ+Δγ. In the two-dimensional analysis of FIG. 11 , the illuminance I(x) at point x is proportional to the difference between the sines of the left and right rays' slant angles: [0000] I ( x )α sin(γ+Δγ)−sin(γ) [0000] This angular requirement can be met by the proper height H of the source image, namely the perpendicular spacing between right ray 112 and left ray 113 , at the lens exit of 112 . Curve 106 of FIG. 10 is a plot of this height H, relative to its maximum value. From this geometric requirement the lens profiles can be directly generated by an iterative procedure that adds new surface to the previously generated surface. [0076] FIG. 12 shows incomplete illumination lens 51 , positioned over LED 120 . It is incomplete in that it represents a typical iteration-stage of generating the entire lens of FIG. 11 . The portion of Lens 111 of FIG. 11 that is shown as a slightly thickened curve terminates at its intersection, shown as point 124 , with right ray 122 . In FIG. 12 , a new left ray 123 is launched that is barely to the right of left ray 113 of FIG. 11 . After going through terminal point 126 and then through previously generated upper surface 121 , it will intercept the target (not shown) at a new point x+dx, just to the right of point x of FIG. 10 . This point will have an already calculated source-height requirement such as curve 105 of FIG. 19 , fulfilled by launching a new right ray 122 from x+dx. Ray 122 will intercept the lens surface at point 125 , upon new surface that has been extended from point 124 . The new surface has a slope determined by the necessity to deflect ray 122 towards point 126 on the interior surface of lens 121 . The location of this point 127 is determined by right ray 122 -S coming from the right edge of LED chip 120 C. The off-axis angle of this ray is determined by the usual requirement that the angular-cumulative intensity of right ray 122 S equal the spatially cumulative illumination at point x+dx, which is known from the desired illumination pattern, such as that shown by curve 105 of FIG. 10 . The slope of this new interior surface, from point 126 to new point 127 , is determined by the necessity of refracting ray 122 S so it joins ray 122 to produce the proper source-image height for the illumination of the target at point x+dx. In this fashion, the generation of lens 121 will be continued until all rays from chip 120 C are sent to their proper target coordinates, and its full shape is completed. [0077] The profile-generation method just described is two-dimensional and thus does not account for skew rays (i.e., out-of-plane rays), which in the case of a relatively large source can give rise to noticeable secondary errors in the output pattern, due to lateral variations in the size of the source image. This effect necessitates a fully three-dimensional source-image analysis for generating the lens shape, as shown in FIG. 13 . [0078] The lens-generation method of FIG. 12 traces left ray 123 through the previously generated inner and outer surfaces to a target point with lateral coordinate x+dx. The pertinent variable is the height H of the source image. In three dimensions, however, rays must be traced from the entire periphery of the LED's emission window out to the target point, where they limit the image of the source as seen through the lens from that point. An illumination lens 51 acts to alter the sources' apparent size from what it would be by itself. The size of the source image is what determines how much illumination the lens will produce at any target point. [0079] FIG. 13A is a schematic view from above of circular illumination lens 51 , with dotted lines showing is incomplete, its design iteration having only extended so far to boundary 131 . Circular source 132 is shown at the center of lens 130 , and oval 133 represents the source image it projects to target point x+dx (not shown). This source image is established by reverse ray tracing from the target point back through the lens to the periphery of the source. The source image is the oval outline 133 on the upper surface where these rays intercept it. Thus the already completed part of the lens will partially illuminate the target point, and a small element of new surface must be synthesized for full illumination. [0080] FIG. 13B is a close-up view showing source ellipse 133 and boundary 131 , also showing curve 134 , representing a small element of new surface that will be added in order to complete source image 133 and achieve the desired illumination level at target point x+dx. Of course, when new upper surface is added there will have to be a corresponding element of new lower surface added as well. Just as enough there must be enough new upper surface to finish the source image, so too must there be enough lower surface to provide the source image to the upper surface. Since both the extent and slope of this new lower surface must be determined as free variables, the design method must be able to calculate both unknowns, but in general the slopes of the new elements of upper and lower surface will be smooth continuations of the previous curvatures of the surfaces. [0081] Traditionally, non-imaging optics deals only with rays from the edge of the source, but the illumination lenses 51 disclosed herein go beyond this when assessing the source image at each target point. The incomplete source image of FIG. 13B gives rise to a less-than-required illuminance at the target point of interest, at lateral coordinate x. In order to calculate this illuminance, however, rays must be reverse traced back to the entire source, not just its periphery. This is especially true when the source has variations in luminance and chrominance. Then the flux from each small elemental area dA of FIG. 13B is separately calculated and integrated over the source image as seen through already completed surface. The deficit from the required illuminance will then be made up by the new surface 134 of FIG. 13B . Its size is such that the additional source image area will just finish the deficit. When the illumination pattern only changes gradually, as with the linear ramps just discussed, the deficit is always modest because the previously generated surface has done a good job of getting close to the required illuminance. The new surface will not have to scrunch the new source image, due to a tiny deficit, nor expand it wildly for a large deficit, because the target pattern is ‘tame’ enough to prevent this. [0082] This design method can be called ‘photometric non-imaging optics’, because of its utilization of photometric flux accounting in conjunction with reverse ray tracing to augment the edge-ray theorem of traditional non-imaging optics. [0083] The iterative process that numerically calculates the shape of a particular illumination lens 51 can begin, alternatively, at either the center or the periphery. If the lens diameter is constrained, the initial conditions would be the positions of the outer edges of the top and bottom surfaces, which then totally determines the lens shape, in particular its central thickness. If this thickness goes below a minimum value then the initial starting points must be altered. While this is conceptually feasible, in practical terms it leaves the problem underdetermined, whereas the reverse ray tracing of FIG. 13A utilizes the previously generated surface via reverse ray tracing. Thus it is easier to begin the design iteration at the center of the lens using some minimum thickness criterion, e.g., 0.75 mm. The height of the lens center above the source would be the primary parameter in determining the overall size of the lens. The other prime factor is how the central part of the lens is configured as a negative lens, that is, whether concave-plano, concave-concave, or plano-concave. Also, a concave surface can either be smooth or have the cusp-type center as shown in FIG. 8 , in the case of strong parasitic losses. [0084] FIG. 14 shows concave-plano lens-center 140 , to be used as a seed-nucleus for generating an entire illumination lens 51 . Its diameter is determined by the width of ray fan 141 , which propagates leftward from the target center (not shown) x=0 at a distance of 23 mm above (to the right of) LED chip 142 , the size of which has been exaggerated for clarity. Ray fan 141 has the width necessary to achieve the desired illumination level at the center of the target, and in short-throw lighting this is less than what the LED would do by itself. This means the central part of the illumination lens 51 must demagnify the source, which is why the lens-center is diverging, with negative focal length. In fact, the very function of lens-center 140 is to provide the proper size of source image (of which ray fan 141 is a cross-section) for the target center, x=0. [0085] FIG. 14 also shows expanding ray fan 143 , originating at the left edge of chip 142 . The will mark the upper edge of a source image as seen from the x-positions at which these left rays intercept the target plane (not shown, but to the right). These rays exemplify how edge rays are sent through previously established surfaces. [0086] FIG. 15 shows concave-concave lens-center 150 , central ray-fan 151 , chip 152 , and left-ray fan 153 . The lens surfaces have about half the curvature of the concave surface of FIG. 14 . [0087] FIG. 16 shows plano-concave lens-center 160 , central ray-fan 161 , chip 162 , and left-ray fan 163 . [0088] In the progression from FIGS. 14 to 16 , the lowest left ray (the one with an arrow) lies at a shrinking slant angle ψ, indicating different illumination behavior and setting a different course towards the final design. All three configurations produce the same illuminance at target x=0, that is to say the same size source image, as shown by the ray fans 141 , 151 , & 161 being of identical size as they arrive at each lens, which is equivalent to saying they produce the same target illuminance at center x=0. [0089] FIG. 17 shows illumination lens 51 , numerically generated from a concave-plano center-lens, as in FIG. 14 . Planar source 171 is the light source from which it was designed. [0090] FIG. 18 shows illumination lens 51 , numerically generated from a concave-concave center-lens, as in FIG. 15 . Planar source 181 is the light source from which it was designed. [0091] FIG. 19 shows illumination lens 51 , numerically generated from a plano-concave center-lens, as in FIG. 16 . Planar source 191 is the light source from which it was designed. [0092] These three lenses were designed utilizing rays from the periphery of the light source, in this case circular. The size of the lens is a free parameter, but etendue considerations dictate that a price be paid for a lens that is too small. In the case of a collimator, the output beam will be inescapably wider than the goal if the lens is too small. In the case of the short-throw illumination lenses 51 disclosed herein, the result will be an inability to maintain an output illumination pattern that is the ideal linear ramp of curve 103 of FIG. 10 , because it requires the source image of curve 106 . If the lens is smaller than the required source image size, then it cannot supply the required illumination. Thus the lens size will be a parameter fixed by the goal of a linear ramp. Lenses that are too small will have some rays trapped by total internal reflection instead of going to the edge of the pattern. If this is encountered in the design process then the iteration will have to re-start with a greater height of the lens-center above the LED. [0093] In conclusion, the preferred embodiments disclosed herein fulfill a most challenging illumination task, the uniform illumination of close planar targets 115 by widely spaced lenses. Deviations from this lens shape that are not visible to casual inspection may nevertheless suffice to produce detractive visual artifacts in the output pattern. Experienced molders know that sometimes it is necessary to measure the shape of the lenses to a nearly microscopic degree, so as to adjust the mold-parameters until the proper shape is achieved. Experienced manufacturers also know that LED placement is critical to illumination success, with small tolerance for positional error. Thus a complete specification of a lens shape necessarily requires a high-resolution numerical listing of points mathematically generated by a fully disclosed algorithm. Qualitative shape descriptors mean nothing to computer-machined injection molds, nor to the light passing through the lens. Unlike the era of manual grinding of lenses, the exactitude of LED illumination lens 51 slope errors, means that without an iterative numerical method of producing these lens-profile coordinates, there can be no successful lenses produced. [0094] The preceding description of the presently contemplated preferred embodiments is not to be taken in a limiting sense, but is made merely for the purpose of describing the general principles of the invention. The full scope of the invention should be determined with reference to the Claims.

A circular LED illumination lens for short throw lighting, for example, as part of a set of such devices installed on mullions in reach-in refrigerator cabinets, to uniformly light access across the rectangular door and shelves. The len has an upper surface with a cavity for the LED, an upper surface the shape of a toroid, generated by an elliptical arc, that serves to magnify the light rays from the LED in an outboard direction, and the minor axis tilted about 17 degrees relatives the center axis of the LED which serves to direct the rays at the center of the shelves. The upper surface also preferably includes a spherical dimple to direct light away from the center axis.

BACKGROUND OF THE INVENTION The Government has rights in this invention pursuant to Grant No. MIP-88-12902 awarded by the National Science Foundation. FIELD OF THE INVENTION This invention pertains generally to multiplexing radio communications signals, and more particularly to increasing spectral capacity by blind adaptive spatial filtering of spectrally overlapping signals. DESCRIPTION OF THE BACKGROUND ART Demand for mobile, portable and stationary personal communication continues to increase as these communication modes become easier to use and more widely available, as they offer a greater variety of services, and as their benefits become more visible. As a result of the increasing demand for a limited number of radio spectrum allocations, new multiplexing techniques that will increase spectral efficiency over conventional multiplexing techniques have been widely sought. Conventional multiplexing techniques rely solely on frequency, time, or code division to allow multiple users in the same locale to communicate simultaneously with the base station in that locale. These techniques include frequency division multiplexing (FDM)--also called frequency division multiple access (FDMA); time division multiplexing (TDM)--also called time division multiple access (TDMA); and code division multiplexing (CDM)--also called code division multiple access (CDMA). For FDM, each user's signals occupy separate frequency bands (one for transmit and one for receive) and no other user is assigned to those bands. FDM alone offers very restricted opportunities for increasing spectral efficiency, namely different spectrally efficient modulation schemes, but the potential of such schemes is limited by the severity of the radio communications environment and, even in the most benign environment, the maximum capacity is relatively low. For TDM, all users occupy the same frequency band, and each is allocated a time slot within which transmission and reception can occur. The frequency bandwidth of each user's signal can be much greater than that in FDM, but a synchronized access scheme is needed to prevent multiple users' signals from being active simultaneously. TDM alone offers no increase in spectral efficiency and requires a complicated access protocol. The inactivity time in typical speech is already exploited in many speech compression methods, so this redundancy has already been used up. For CDM (using direct-sequence spread spectrum signals), all users' signals occupy the same band and can be active simultaneously. Each user is assigned a unique spreading code which is used at the receiver to separate a desired user's signal from the rest. CDM offers some limited increases in spectral efficiency but requires power control methods that can be difficult to implement in severe fading environments. There can also be some burden in managing the distinct codes that are assigned to the users. As a result, space division multiplexing (SDM)--also called space division multiple access (SDMA)--was developed to employ spatial filtering to separate spectrally overlapping signals from different users. For SDM, a system can separate a desired user's signal from the rest if its spatial characteristics (e.g., direction of arrival) are sufficiently different from those of the other users. SDM can multiply spectral efficiency by a factor equal to the number of spatially separable channels sharing a spectral band. Since this number can be roughly equal to the number of elements in the antenna array (which can practically be on the order of 100 depending on physical and/or cost limitations at the base station), potentially large increases in spectral efficiency are possible. Transmission power can be reduced, thereby reducing the interference level for other users and increasing mobile (or portable) battery life. Also, reduction or elimination of multipath fading can improve the received signal quality. However, except for variations of these techniques that use fixed multibeam or multisector antennas to further increase capacity, none of them fully exploits the multiplicity of spatial channels that arises because each user occupies a unique spatial location. SDM techniques adapt the antenna array either by estimating the directions of arrival of the spectrally overlapping signals and then using these estimates to compute appropriate weights for the spatial filter, or by minimizing the time-averaged squared error between a known training signal and the output of the spatial filter. Several methods for adaptively adjusting spatial filters based on antenna arrays have been heretofore developed. For example, in the "known reference signal" approach, a reference signal is transmitted in addition to the message signal. As a result, channel capacity for the message is reduced, especially as the severity of the environment increases the need for adaptation and as the number of elements in the antenna array is increased. When TDM of reference and message signal is used, receiver complexity is increased, some start-up overhead is incurred in assigning training codes, and signal bandwidth must be increased to compensate for reduced message capacity. With the "time redundancy" approach, each user has a unique message block length (which is an extra complication), and a given block is transmitted twice (which reduces effective capacity by 50 percent). With the "frequency redundancy" approach, the message is transmitted at two different carrier frequencies, which reduces effective capacity by 50 percent. With the "DF-based beamforming" approach, for moderately to widely separated multipath reflections, and for a large number of sources in a frequency band (which is desirable for increased spectral efficiency), direction-finding (DF) based methods are impractical or unusable and incur prohibitive computational expense. Array calibration problems also arise. It can be seen therefore, that SDM versions based on direction estimation have numerous disadvantages, including computationally intensive algorithms, poor performance in the presence of multipath signals arriving from different directions, the need to measure, store, and update array calibration data, and considerable sensitivity to errors in the array calibration data. Versions that require a training signal have different disadvantages, including the need to use spectral capacity to periodically transmit the training signal, the need to synchronize the received and locally generated copies of the training signal, and the need to adaptively increase or decrease the duration of the training signal to accommodate varying levels of interference. Therefore, there is a need for a spatial filtering method of multiplexing communications signals which overcomes the foregoing deficiencies. The present invention fulfills that need. SUMMARY OF THE INVENTION The present invention pertains generally to spatial filtering techniques, and more specifically to adaptive space, time and frequency multiplexing. This multiplexing method is neither dependent on direction of arrival estimation nor on use of a reference or training signal. By way of example and not of limitation, an adaptive antenna array at a base station separates temporally and spectrally overlapping received signals of different users and transmits directively to each user, exploiting multipath when present. The invention uses the technique of restoring the spectral coherence of a received signal of interest impinging on an array of antennas in order to adapt the spatial filter for reception at the base station and determine the optimum reception pattern for the signal, which filter can be reused for transmission with a radiation pattern equal to that of the adapted reception pattern. Unlike schemes that rely solely on frequency, time, or code division multiplexing and thus use only one spatial channel, the present invention exploits space as well as partial time and frequency division multiplexing (STFDMA) and thus uses multiple spatial, temporal, and spectral channels. Users whose signals arriving at the base station are spatially separable are assigned to spectral bands that overlap, and users whose signals arriving at the base station are spatially inseparable are assigned to disjoint spectral bands. Also, signals coming from the individual users can be assigned to time intervals that are interleaved with those assigned to signals coming from the base station. Under the assumption that users are sufficiently well distributed throughout a geographical area, all available spatial and spectral channels can be used effectively. Since the number of multiple spatial channels that can be separated from each other by the antenna array is approximately equal to the number of antenna elements in the array (which can be quite large), overall capacity can be much greater than schemes using a single spatial channel. Also, unlike adaptive array schemes that require direction estimation processors or known training signals, the present invention uses a property restoral method to exploit some property, such as the spectral redundancy (cyclostationarity or spectral correlation or spectral coherence), that is already present in essentially all digital communication signals and thus does not require array calibration data or computationally intensive multidimensional searches for direction finding (DF). Nor does it waste channel capacity by transmitting a training signal. An object of the invention is to increase the communications capacity of limited spectral allocations. Another object of the invention is to provide for overlapping spectral channels without unacceptable interference between users. Another object of the invention is to spatially filter communications signals without the need for a training signal. Another object of the invention is to spatially filter communications signals without the need to determine direction of arrival. Another object of the invention is to blindly adapt an antenna array. Another object of the invention is to mitigate multipath fading and shadowing of received signals. Another object of the invention is to directively transmit signals to users from a base station without employing direction finding techniques. Further objects and advantages of the invention will be brought out in the following portions of the specification, wherein the detailed description is for the purpose of fully disclosing preferred embodiments of the invention without placing limitations thereon. BRIEF DESCRIPTION OF THE DRAWINGS The invention will be more fully understood by reference to the following drawings which are for illustrative purposes only: FIG. 1 diagrammatically shows the typical time multiplexing windows employed in the present invention. FIG. 2 diagrammatically shows the partial frequency division multiplexing employed in the present invention. FIG. 3 is a functional block diagram showing a generalized receiver employing the present invention. FIG. 4 is a flow diagram showing the general reception steps of the present invention. FIG. 5 is a flow diagram showing the general transmission steps of the present invention. FIG. 6 is a functional block diagram of one embodiment of an overall communications system employing the present invention. FIG. 7 is a functional block diagram of an alternative embodiment of an overall communications system employing the present invention. FIG. 8 is a schematic block diagram of one embodiment of the temporal filtering, signal routing and adaptive spatial filtering element shown in FIG. 6 and FIG. 7. FIG. 9 is a schematic block diagram of one embodiment of a bandpass filtering and downconversion element shown in FIG. 8. FIG. 10 is a schematic block diagram of one embodiment of a splitter element shown in FIG. 6 and FIG. 7. FIG. 11 is a schematic block diagram of one embodiment of an input summer element shown in FIG. 8. FIG. 12 is a schematic block diagram of one embodiment of a vector scalar multiplier element shown in FIG. 8. FIG. 13 is a schematic block diagram of one embodiment of an inner product element shown in FIG. 8. FIG. 14 is a partial schematic diagram showing the typical configuration of a signal router element shown in FIG. 8. FIG. 15 is a schematic block diagram of one embodiment of a direction of arrival estimator element shown in FIG. 6. FIG. 16 is a schematic block diagram of one embodiment of a time difference of arrival estimator elements shown in FIG. 7. DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring more specifically to the drawings, for illustrative purposes the present invention is embodied in the drawings of FIG. 1 through FIG. 16. It will be appreciated that the method of the present invention may vary as to specific steps and their order of implementation, and that the apparatus of the present invention may vary as to configuration and as to details of the parts without departing from the basic concepts as disclosed herein. The conventional transmit/receive configuration for multiuser cellular communication consists of a base station through which all users in a given cell communicate. The base station then communicates with other base stations and with a central switching office to provide cell-to-cell communication and cell-to-wire-line communication, respectively, for the individual users. Communication among base stations is not, in the usual sense, multiuser communication and, therefore, is not presented herein. Communication between individual users in a cell and the base station in that cell can, in principle, exploit SDMA by performing adaptive spatial filtering at either each user's location or the base station or both. However, adaptive arrays at the mobile unit (or the portable or stationary personal unit) are prohibitively expensive and subject to neglect or abuse by the users. Also, adaptive spatial filtering at the mobile unit is unlikely to be effective since the signals from the base station and the other interferers can arrive from a nearly uniform angular spread over 360 degrees (due to scattering, for example, from buildings, other cars, and the ground in the mobile communication environment). Therefore, in the present invention the existing single omnidirectional antenna at the mobile unit is retained, but a multi-element antenna array is used at the base station. Spatial filtering as disclosed herein requires the use of a multi-element antenna array with a large number of elements. Therefore spatial adaptation occurs only during the transmission from the mobile unit to the base station; transmission from the base station to the mobile unit must use a spatial filter that is developed during said adaptation. In addition, the spatial filtering method of the present invention is frequency dependent and, therefore, both directions of transmission must use the same carrier frequency. In order to use the same frequency for duplex communications, the present invention also employs time division multiplexing of the signals from the base station and the users. That is, reception at the base station from all mobile units is temporally separated from transmission from the base station to all mobile units. The base station transmits to the user unit for some time period T, the user then transmits to the base station for time period T, and the cycle repeats. Therefore, spatial filtering at the base station separates spectrally and temporally overlapping signals of multiple users during transmission from and reception at the base station. The lack of direct spatial filtering at the mobile unit does not imply, however, that mobile units must be prevented from interfering with each other, because the TDM scheme employed by the present invention insures that all mobile units transmit at the same time during one time period, and that they all receive at the same time in another time period. During the time period that the signals are received by the base station, the base station blindly adapts its antenna array using the spectral coherence restoral (SCORE) method of the present invention. With SCORE, spectral redundancy already present in the signal is exploited and the weights of spatial filters are computed while the received data is saved. To understand use of the SCORE method for blindly adapting an antenna array, let the vector x(n) denote the sampled complex envelopes of the output signals of M antennas having an arbitrary geometric arrangement and arbitrary directional characteristics (but preferably omnidirectional). To maximize spatial resolution while preventing grating lobes (ambiguities), the antennas are typically separated by approximately one half of the wavelength corresponding to the highest frequency in the reception band. It should be noted that this geometry is fundamentally different from that used in most space diversity systems, in which antennas are spaced many wavelengths apart so as to decorrelate multipath propagation parameters at the different antennas. Also, let y(n) w H x(n) be the output of the spatial filter, where w is referred to as the weight vector representing a set of weights that realize the reception pattern of the signal of interest as it impinges on the array of antennas and which are used to extract the signal of interest. By choosing w appropriately, an adaptive receiver can enhance (steer beams in the direction of) desired signals, attenuate (steer nulls in the direction of) undesired signals, and minimize the contribution of additive noise (through coherent processing gain and by minimizing the height of sidelobes in the antenna pattern). In general, the sum of the number of beams and the number of nulls that can be controlled is equal to one less than the number M of antenna elements. Instead of choosing w to maximize the degree of correlation between y(n) and a known training signal as is typically done in conventional schemes, the SCORE method chooses w and an auxiliary spatial filter c to maximize the degree of correlation (correlation coefficient) between y(n) and an auxiliary output signal u(n) c H x(n-τ) * e j2 παn : ##EQU1## Since R yu is the cyclic cross-correlation between the spatial filter output w H x(n)=y(n) and the conjugated auxiliary spatial filter output c H x * (n-τ), then the quantity being maximized in equation (1) is a measure of the degree of conjugate spectral coherence between these two spatial-filter outputs. Since the presence of interfering signals and noise that corrupt the signal of interest in x(n) decreases the degree of conjugate spectral coherence by increasing the denominator in equation (1) relative to the degree exhibited by the uncorrupted signal of interest, then spatial filtering with w and c to maximize the correlation coefficient as in equation (1) can be interpreted as restoring conjugate spectral coherence. Thus, the criterion in equation (1) is referred to as spectral coherence restoral (SCORE). Also, since R yu can be interpreted as the Fourier coefficient for the regenerated sine wave at frequency α in the product waveform [w H x(n)][c H x * (n-τ)], then the SCORE method can be seen to maximize the average power of this sine wave relative to the average powers of the waveforms w H x(n) and c H x * (n-τ). Under the assumption that L.sub.α signals have cycle frequency α, it can be shown that the solutions to the equation in (1) are given by the L.sub.α most dominant eigenvectors w 1 , for l=1,. . . ,L.sub.α that satisfy R.sub.xx.spsb.*.sup.α (τ)R.sub.x.spsb.*.sbsp.x.spsb.*.sup.-1 R.sub.xx.spsb.*.sup.αH (τ)w.sub.1 =λ.sub.1 R.sub.xx w.sub.1 (2) and similarly for c. It should be noted that only the most dominant eigenvector of equation (2) is needed when only one signal exhibits cyclic conjugate correlation at the chosen value of α, in which case the matrix product on the left-hand side of equation (2) has rank equal to one, and thus this eigenvector can be found using a simple iteration based on the power method of computation. In the present invention, this is true in the absence of multipath reflections of the desired signal. In the presence of K spatially separable multipath reflections of the desired signal, each of the K+1 most dominant eigenvectors extracts a linear combination of the multipath reflections; thus, the most dominant eigenvector can still be used to extract the desired signal, although an adaptive equalizer might be required to mitigate the smearing of the signal in time if the delay spread of the multipath is too great. Alternatively, note that the desired signals (those having cycle frequency α) are the only ones common to both x(n) and x(n-τ) * e j2 παn in the sense that the correlation between these two data sets is asymptotically equal to the correlation between the components due to the desired signals and their frequency-shifted and conjugated versions. From this point of view, estimating the desired signals is equivalent to estimating the common factors of the two data sets x(n) and x(n-τ) * e j2 παn. Common factor analysis (also called canonical correlation analysis) is a well-known technique in multivariate analysis. Formulating the problem in this way leads to exactly the same solution of equation (2). The SCORE method can also estimate the desired signals that are common to both x(n) and x(n-τ)e j2 παn, in which case the conjugation symbols * are dropped from equation (2), although this variation is not required in the present invention. It should be noted that the SCORE method is based upon the cyclostationarity exhibited by a signal. A vector-valued complex envelope x(n) exhibits cyclostationarity if it is correlated with either a frequency-shifted version of itself (i.e., if it exhibits spectral coherence) for any nonzero frequency shift α or a conjugated and frequency-shifted version of itself for any frequency shift α. Mathematically, this correlation (or spectral coherence) is expressed in terms of the cyclic autocorrelation matrix R.sub.xx.sup.α (τ) (3) or the cyclic conjugate correlation matrix R.sub.xx.spsb.*.sup.α (τ) (4) respectively, where R.sub.xx.sup.α (τ) [x(n)x(n-τ).sup.H e.sup.-j2παn ].sub.∞ (5) R.sub.xx.spsb.*.sup.α (τ) [x(n)x(n-τ).sup.T e.sup.-j2παn ].sub.∞ (6) with ##EQU2## and where (·) T and (·) H denote the matrix transposition and matrix conjugate transposition operators, respectively. The values of α for which either of these correlation matrices are nonzero are the cycle frequencies of the signals comprising x(n). Since equations (3) and (4) can be reinterpreted as the Fourier coefficients for the matrices of conjugate and nonconjugate lag-product waveforms x(n)x(n-τ) H and x(n)x(n-τ) T , then it can be seen that x(n) exhibits cyclostationarity (or spectral coherence) if and only if the lag-product waveforms contain finite-strength additive sine-wave components with frequency equal to the cycle frequency α. That is, cyclostationarity means that sine waves can be generated by multiplying the signal by a delayed and possibly conjugated version of itself. Most digital communication signals exhibit cyclostationarity as a result of the periodic sampling, gating, keying, and mixing operations in the modulator. For example, the cycle frequencies of binary phase shift keying (BPSK) are equal to the doubled carrier frequency offset, harmonics of the baud rate, and sums and differences of these. More specifically, if x(n) contains a BPSK signal having carrier offset f c (relative to the frequency of the downconverter) and baud rate f b , then R xx .sup.α (τ) is not identically zero for α=kf b for integers k, and R xx .spsb.*.sup.α (τ) is not identically zero for α=2f c +kf b for integers k. The useful values of τ in the correlation matrices are typically between 0 and 1/2f b . The only case of particular interest in the present invention is the fact that for a scalar BPSK signal having carrier frequency offset f c , the magnitude of the cyclic conjugate correlation R xx .spsb.* 2f .sbsp.c (τ) is maximized at τ=0 regardless of the pulse shape. Measurements of these two types of cyclic correlations are useful because they select contributions from only the signal components that exhibit the specified cyclostationarity property and discriminate against all others. This is analogous to the property that measurements of the correlation between a desired signal corrupted by additive interference and noise and an uncorrupted version of the desired signal (e.g., the training signal) select only the contributions from the desired signal and discriminate against all others. The utility of exploiting cyclostationarity to gain signal-selectivity has been demonstrated for many applications, including adaptation of antenna arrays, estimation of directions of arrival, estimation of time difference of arrival, detection, and the like. Referring to FIG. 1, during the receiving and adaptation phase 10, the weights of the spatial filters are computed. At the end of that phase, the weights are applied to the received data to separate the signals sent by the mobile units. During the transmission phase 12, the weights computed in the receiving phase 10 are used to direct the transmission of each outgoing signal to the appropriate mobile unit. The duration of the phases is limited here primarily by the reciprocal of the fast fading rate (the maximum rate is approximately 100 fades/second, so the duration of each phase can be about half the reciprocal, or 5 milliseconds) because the propagation conditions must remain relatively constant over this time for the spatial filtering to be effective. A "dead time" 14 during which neither reception nor transmission occurs is inserted between each phase to allow the trailing edges of the signal from or to the farthest mobile unit to arrive at their destination and to allow the microwave hardware at the base station and the mobile unit to switch between transmission and reception modes (since the same spectral band is used for both). This dead time is negligible (approximately 5 microseconds in a cell having radius of 1 mile) compared to the reception and transmission times (approximately 5 milliseconds). The cycle summarized in FIG. 1 is then repeated. To avoid the waste of channel capacity and additional synchronization difficulties that occur when a training signal is used to adapt the array, the SCORE method of blind adaption is used to separate signals based on their differing carrier frequencies. Thus, the SCORE method represented by equation (2) is implemented for each active user in the cell. Although it is conceivable that differing baud rates could also be used to separate signals, the additional complexity of accommodating a unique baud rate for each user is prohibitive. Consequently, as can be seen in FIG. 2, each mobile unit is assigned a unique carrier frequency (accomplished during call initiation and hookup) according to the relationship f.sub.1 =f.sub.0 +(l) (f.sub.sep) for l=1, . . . , L (8) where f 1 is the carrier frequency 20 of the user numbered 1, f 0 is the lowest frequency 26 in the reception band, f sep is the separation 22 between adjacent carrier frequencies, and L is the maximum number of users that can be accommodated in the cell. The choice of f sep is determined by the maximum Doppler shift (about 100 Hertz in the land mobile cellular radio environment), and by some convergence-time considerations in the SCORE method, namely the time required for an estimate of a cyclic conjugate correlation to adequately reject contributions from signals having adjacent carrier frequencies (at least 100 Hertz separation is required for adequate rejection in the 5 milliseconds during which adaptation occurs; this follows because the cycle resolution of the measurement of the cyclic conjugate correlation matrix, and thus the minimum separation of the doubled carriers, is equal to the reciprocal of the averaging time). The value of f sep is also limited by the maximum number of spectrally overlapping signals 24 that can be separated by the antenna array. Because transmission from the base station to each mobile unit is highly directional, a smaller frequency reuse distance, such as three, can be tolerated in the present invention than in the conventional analog frequency modulation (FM) scheme in which it is seven. The success of the SCORE-STFDMA method depends on the ability to use spatial filters to spatially separate spectrally overlapping signals and the ability to use conventional spectral filters to separate spatially inseparable signals. This frequency allocation method coupled with the use of the SCORE method accomplishes this under the assumption that spatially inseparable users can be assigned to disjoint spectral bands. One approach to accomplish this is to obtain and use knowledge of the directions of arrival of the signals from the mobile units. This in turn can be accomplished either by using a location sensing device (e.g., global positioning system) in each mobile unit, which could be prohibitively expensive, or by using the signal-selective Cyclic MUSIC or Cyclic Least Squares (CLS) direction estimation methods at the base station, or by using the signal-selective Cyclic Cross Correlation (CCC) time-difference-of-arrival (TDOA) estimation algorithm at the base station and one or two auxiliary reception sites within the cell. In the Cyclic MUSIC approach, we measure R.sub.xx.spsb.*.sup.α (τ)=<x(n)x(n-τ).sup.T e.sup.-j2παn>.sub.N where α equals twice the carrier frequency of the desired user. We then compute the singular value decomposition R.sub.xx.spsb.*.sup.α (τ)=UΣV.sup.H of R xx .spsb.*.sup.α (τ) where U and V are M×M unitary matrices and Σ is diagonal with elements σ 1 ,. . . , σ M arranged in descending order σ 1 ≧. . . ≧σ M ≧0. Then, we search for the highest peak in the function P(θ)=|U.sub.1.sup.H a(θ)| where the corresponding value of θ is the estimated direction of arrival of the desired user, U 1 is the first column of U, and a(θ) is the array response vector for angle θ and is typically known for many values of θ equally spaced from 0 degrees to 360 degrees. In the CLS method, we measure R.sub.xx.spsb.*.sup.α (τ)=<x(n)x(n-τ).sup.T e.sup.-j2παn>.sub.N where α equals twice the carrier frequency of the desired user. We also measure R x * x * (τ)=<x(n) * x(n) T > N and compute R=R.sub.xx.spsb.*.sup.α (τ)R.sub.x.spsb.*.sbsp.x.spsb.*.sup.-1 R.sub.xx.spsb.*.sup.α (τ).sup.H and search for the highest peak in the function P(θ)=a(θ) H Ra(θ). The corresponding value of θ is the estimated direction of arrival of the desired user. The Cyclic MUSIC and CLS approaches, however, require the use of a calibrated array, but this array can be much smaller (e.g., only 4 elements) than the one used for spatial filtering because a unique carrier frequency is assigned to each mobile unit and these methods are signal selective. In the CCC method of TDOA estimation, we compute a cross conjugate cyclic spectrum estimate S yz .spsb.*.sup.α (f) and then minimize the weighted inverse Discrete Fourier Transform (DFT) ##EQU3## with respect to the TDOA estimate d, where P(f) is the raised-cosine pulse-transform used in the BPSK signal. Multipath propagation will result in multiple peaks. One of several possible methods for estimating the cross conjugate cyclic spectrum is to frequency smooth the cross conjugate cyclic periodogram ##EQU4## Where Y and Z are the DFT's of the signals received at main and auxiliary stations and W(f) is a smoothing window. To actually locate a user would require intersection of the two location-hyperbolas determined by two such TDOA estimates obtained from two pairs of reception stations, each pair of which includes the same base station and a unique auxiliary reception site. However, a single TDOA estimate for a set of estimates corresponding to multipath propagation from a single pair of reception stations could be adequate for determining spatial separability. Also, it is possible to forego the task of locating mobile units and to assign frequencies in the least active bands (or at random) and make reassignments whenever co-channel interference is detected after the spatial filter has converged. This detection can possibly be accomplished using the SCORE method or, alternatively, can be readily detected by the user at the mobile unit and reported (by the push of a button) to the base station. Although there is some flexibility in the choice of a modulation type, the type chosen for the present invention for several reasons is BPSK using Nyquist-shaped pulses having 100% excess bandwidth. The strength of the cyclic conjugate correlation R xx .spsb.* 2f .sbsp.c for a BPSK signal having carrier offset f c is the same as the strength of the signal itself, which speeds convergence of the SCORE adaptation method. Although BPSK having 100% excess bandwidth is not as spectrally efficient as modulation types using less excess bandwidth and/or higher-order alphabets, it is less susceptible to noise, easier to synchronize to, and its 200% spectral redundancy (100% due to double sideband and 100% due to excess bandwidth) can be effectively exploited for equalization and reduction of residual co-channel interference. Since the cyclic conjugate correlation characteristics of differential phase shift keying (DPSK) are identical to those of BPSK, DPSK can be used for transmission from the base station so as to simplify the receiver in the mobile unit. The actual baud rate and thus the bandwidth of the BPSK signal depend on the rate of the vocoder used. In the present invention, a vocoder rate of 8 kilobaud/second is used. Since transmission and reception are multiplexed in time, the actual rate that must be supported by the channel is 16 kilobaud/second, which yields a BPSK bandwidth of 32 Khz. In general, for a total system-bandwidth B t , single-user channel-bandwidth B c , and frequency-reuse factor r, the maximum number L of users that can be accommodated by the frequency allocation scheme in equation (8) is L=(B t /r-B c )/f sep +1. The number M of antenna elements required to separate these signals is bounded from below by the number K of users whose signals are spectrally overlapping with any given user's signal, where M>K=2(B c /f sep -1). Using B c =32 Khz and f sep =1 Khz, at least 63 antenna elements (which can be omnidirectional) are needed to separate the signals of all users, assuming that the energy from each user arrives at the base station from a single direction, and assuming that the users are approximately uniformly distributed throughout the cell. In practice, more antenna elements might be required to achieve adequate performance at full capacity in the presence of spatially separable multipath, although fewer antenna elements can suffice if a lower capacity is opted for and appropriate channel allocation is done. Also, adaptive equalization should follow the spatial filtering to mitigate the time-smearing effects of multipath. A block diagram of a generalized receiver 30 at the base station is shown in FIG. 3. The output signals 34 of the M antenna elements 32 are processed by individual preprocessing systems 36 that perform bandpass filtering, quadrature downconversion, sampling, and channelization on each output signal at each antenna. Channelizers 38 transform the resultant scalar input signal to a L×1 vector of signals, each of which is obtained by bandpass filtering (centered on a particular user's carrier frequency and having bandwidth equal to that of this user's signal) the input signal and downconverting it to baseband, where L is the maximum number of users that the system can accommodate. The outputs of the M channelizers 38 then pass through a routing network 40 that routes the M channelizer outputs corresponding to each user to a SCORE processor 42. That is, the M vector inputs each having dimension L and corresponding to a particular antenna element are rearranged to yield L vector outputs each having dimension M and corresponding to a particular user's carrier frequency. An example of a 3×2 to 2×3 router can be seen in FIG. 14. Each M×1 vector is then processed by a corresponding SCORE processor device 42 to extract the signal of the user that is assigned the corresponding carrier frequency and separate that signal into a usable output signal 44. Referring now to FIG. 4, a typical implementation of the invention would begin with call initiation on the control channel at step 50. Here a call can be initiated either by the base station or by the user. Call initiation is preferably performed on separate control channels so that communication channels are not wasted. These control channels would typically occupy distinct, non-overlapping spectral bands. If the user initiates the call then the reception cycle can proceed. On the other hand, if the base station initiates the call the user must first respond on the control channel before the reception cycle can proceed. If direction of arrival information is to be used for frequency allocation, then the reception cycle proceeds with step 52 where an estimation of the direction of arrival of the signal from the user (signal of interest) is made. This option is useful because the signals from users who are not sufficiently separated geographically may not be spatially separable and, therefore, should be allocated disjoint carrier frequencies. At step 54 the determination of spatial separation is made. If the signal of interest is spatially separable from the other users' signals, then at step 56 that user is assigned a carrier frequency which, when modulated, results in a signal having a bandwidth which spectrally overlaps with that of other users, but whose carrier frequency is sufficiently separated from the carrier frequencies of the other users that signal-selective spatial filtering can be performed. If the signal of interest is not spatially separable, then at step 58 the user is assigned a carrier frequency which is sufficiently removed from those of the other users that the signals will not overlap. It should be clarified that the direction of arrival estimation system will not necessarily locate each mobile unit; rather it will determine possible multiple apparent locations for each unit that result from multipath propagation due to reflections and shadowing. But, it is these apparent locations--not the actual location--that are relevant in assessing spatial separability. Steps 52 through 58 are optional and can be omitted. If carrier frequencies assigned without an initial determination of spatial separability, then the reception cycle would proceed from step 50 to step 60. At step 60, carrier frequencies are allocated in the least active band. If interference between users results, then a reassignment of carrier frequencies can be made at step 62 if requested by the user. As can be seen, therefore, direction of arrival information is neither required nor it is a necessary element of the SCORE-STFDMA method of signal processing. Once the user is assigned a carrier frequency which may or may not result in spectral overlap of the modulated signal with those of others, communications begins. At step 64, the signal of interest together with interfering signals is received on each antenna in an array of M antennas. At step 66, bandpass filtering, quadrature downconversion, and sampling of the signal of interest and interference occurs for each antenna in the array. Since a particular user's signal will be separated from signals of other users by processing the M output signals of the M bandpass filters that are centered on the particular user's signal, each group of M corresponding bandpass filter outputs is routed to a different SCORE processor ar step 68. Once the signals of interest and interference are routed, at step 70 the SCORE method of adaption based on restoring spectral coherence is applied to determine the weight vector w. Then, at step 72, the inner product of the weight vector w and the signal of interest and interference is determined. This inner product will be separate and distinct for the signals of all users and, therefore, the signal of interest is separated from those of other users at step 74. It is important to note that the foregoing steps result in an implicit determination of an optimum reception pattern for the signal of interest as it impinged on the antennas in the array. This reception pattern can have single or multiple beams and multiple nulls determined by multipath reflections from buildings and by locations of interfering users. The present invention uses that reception pattern, as represented by the SCORE weight vector, as the foundation of spatial multiplexing. Once the signal of interest is separated from those of other users, the signal is equalized at step 76 and routed out of the base station at step 78 where it interfaces directly with the wireline phone network or is passed to another base station for interconnection with the wireline phone network. Referring now to FIG. 5, a responsive message from the wireline phone network (which may be routed through the base station directly or through multiple base stations) is digitized for transmission at step 80. The carrier frequency is then modulated with the digital message at step 82. At step 84, the modulated signal is then multiplied by the weight vector w developed in step 70. At step 86, the vectored signal is passed through a L×M to M×L router for routing to a corresponding antenna. At step 88, the signals from all users to be routed to specified antennas are summed. The summed signals are applied to the antennas at step 90. The overall effect of this process is that the radiation pattern of the signal transmitted by the base station to the user will match the reception pattern of the user's signal as seen by the antenna array at the base station. Therefore, the output signals and phasing of those signals may vary from antenna to antenna in the array. FIG. 6 shows a block diagram of one embodiment of an overall system which implements the steps described above. One of the antennas 140 in the antenna array 138 is coupled to a splitter/combiner 102 through interconnection 104 and is used to transmit and receive on the control channel. Splitter 102, which can be seen in more detail in FIG. 10, includes a pair of bandpass filters 106, the outputs of which are coupled to controller 108 through interconnections 110 and 112, respectively. Splitter 102 is used to separate the spectrally disjoint control signals received from the mobile user and the control signals transmitted to the mobile user, and to separate the control channel from the band occupied by active users. The control channel is used for call initiation and coordination between the user and the base station as previously described. A calibrated antenna array 114 contains a plurality of antennas 116 (more than 4) which are separately coupled to a plurality of splitters 118 through interconnections 120. Splitters 118 are similar in configuration to splitter 102 previously described and, where eight antennas are used, the outputs of splitters 118 are coupled to an 8×2 to 2×8 router 122 as shown through interconnections 124. Referring also to FIG. 14, a typical router configured for 3×2 to 2×3 can be seen. As previously described, the function of a router is that the M vector inputs each having dimension L and corresponding to a particular antenna element are rearranged to yield L vector outputs each having dimension M and corresponding to a particular user's carrier frequency. Router 122 permits separation of a set of signals from the eight antennas in antenna array 114, one set representing control signals and the other representing user signals. Control output 126 is coupled to control direction of arrival (DOA) estimator 128, and user output 130 is coupled to user DOA estimator 132. The DOA data corresponding to the control signals is coupled to controller 108 through interconnections 134, while similar data corresponding to users is coupled to controller 108 through bus 136. Controller 108, which can be a microcomputer or the like, performs the functions of call initiation, carrier allocation, and interfacing with the telephone network 148. Optionally, elements 114 through 136 which comprise the apparatus needed to estimate directions of arrival can be omitted or replaced by other elements appropriate to the implementation of a TDOA estimator such as CCC. FIG. 7 shows an alternative embodiment of an overall communications system employing the present invention. Elements 102, 104, 108, 110, 112, 138, 140, 142, 144, 146, 148, and 150 in FIG. 7 are identical to the corresponding elements in FIG. 6. The embodiment shown in FIG. 7 differs from that shown in FIG. 6 in the details of how the directions of arrival of the active mobile units and control signals are determined. Elements 117, 119, 121, 123, 125, 127, 129, 131, 133, 135, 137, 139, 141, and 143 shown in FIG. 7 comprise alternate means for estimating the directions of arrival. Two auxiliary antennas 117, 119 are located in different areas of the cell and should be as far as possible from the base station. Splitters 121, 123 are similar in configuration to splitters 102 previously described and separate the signals received at antennas 117 and 119 into control signals and signals from active mobile units. The outputs of splitters 121, 123 are separately coupled to two TDOA estimators 133, 135 through interconnections 125, 127, 139, and 131 as shown. TDOA estimators 133, 135 can be seen in more detail in FIG. 16. The TDOA estimators measure the DOA's using methods that differ from the methods used in the DOA estimators 128, 132 shown in FIG. 6. The received control signals are routed from splitter 102 through interconnection 110 to a bank of bandpass filters 143 that splits their inputs into a plurality of control signals occupying disjoint spectral bands and routes them through interconnection 139 to TDOA estimator 133. The resulting DOA's of the control signals are coupled through interconnection 137 to the controller 108. The received and spatially filtered signals of the active mobile users are routed through interconnections 146 to TDOA estimator 135. The resulting DOA's of the active mobile users are coupled through interconnections 141 to the controller 108. For normal communications, the users' signals are preferably received and transmitted using an antenna array 138 (for example, a circular array) which contains M antennas 140 (for example, omnidirectional antennas). Antennas 140 are coupled to SCORE-STFDMA module 142 through interconnections 144, there being one input (output) for each antenna M. SCORE-STFDMA module 142 performs the temporal filtering, signal routing, and adaptive spatial filtering functions of the system. SCORE-STFDMA module 142 has a plurality of output lines 146 to route communications from the users to the wireline phone network 148, and a plurality of input lines 150 to receive communications from the wireline phone network 148 for transmission to the users. Controller 108 provides the interface to the wireline phone network 148. Referring now to FIG. 8, SCORE-STFDMA module 142 includes a transmit/receive switch 152 for each of its connections to an antenna 140. Transmit/receive switches 152 are coupled to a clock 154 which controls the time division multiplexing windows of the transmitted and received signals through interconnections 156. Signals received from a particular antenna 140 are subjected to bandpass filtering, quadrature downconversion and sampling by a processing module 158 through interconnections 160. The output of each processing module 158 contains information for each of the L users of the system received on a particular antenna. Since there are M antennas in the base station antenna array 138, it is necessary to select each of M received signals for a particular user and route them for processing. This is performed by router 162 which is coupled to processing module 164 through interconnections 164. The output of router 162 contains, for each user, the signals from each of the M antennas. For each user therefore, there are M signal components which must be processed by a SCORE processor 164 which is coupled to router 162 through interconnections 166. SCORE processor 164, which has M outputs and inputs, determines the weight vector w for each user's signals as previously described. The outputs of a SCORE processor 164 are then applied to that user's received signals in an inner product multiplier 168 which is coupled to the SCORE processor 164 through interconnections 170. There, the signals are also summed and the composite signal is output to controller 108 on an interconnection 146. FIG. 13 schematically shows an inner product multiplier 168. The output signals on interconnections 146 are represented by w H x(n) for the particular user. Referring now to FIG. 9, processing module 158 includes a bandpass filter 172 which is coupled to a quadrature downconverter 174 for conversion to baseband for preconditioning and anti-aliasing. The resultant signal is filtered by low pass filter 176 and converted into digital data by analog to digital convertor 178. Transformation module 180 performs a 1024-point Fast Fourier Transform to split the band into 1024 bands which are 1 Khz wide. Grouping module 182 groups the bands into 64 Khz subbands prior to a 64-point inverse Fast Fourier Transform by inverse transformation modules 184. Therefore, the function of processing module 158 is typically to split a spectral band having a width of 1024 Khz into several overlapping bands having a width of 64 Khz whose centers are separated by 1 Khz. Referring again to FIG. 8, digital information which is to be transmitted to the user is input to SCORE-STFDMA module 142 through interconnections 150. Modulators 186 place that data on the carrier signal assigned to the user. Modulators 186 are coupled to vector scalar multipliers 188 through interconnections 190, where the weight vector w is applied to the transmitted signal. In other words, the weight vector w developed from that user's received signal by the SCORE processors 164 is used to condition the transmitted signal and separate it into components which will be separately routed to the M antennas in antenna array 138. FIG. 12 schematically shows a typical vector scalar multiplier used herein. Vector scalar multipliers 188 are coupled to an L×M to M×L router 192 through interconnections 194. Router 192 takes the M signal components for each user and reorganizes that information so that each antenna 140 will have the its corresponding information for all users. L-input summers 196, which are coupled to router 192 through interconnections 198, sum the signal information for all users for a given antenna so that the composite signal can be transmitted through transmit/receive switches 152 through interconnections 200 and on to antennas 140. FIG. 11 shows a schematic of a typical L-input summer used with the present invention. FIG. 14 shows an example of a 3×2 to 2×3 router configuration which can be expanded to any number of users and antennas. Once all of the signals are applied to the antennas in antenna array 138, the radiation pattern of the signal transmitted to the user will match the reception pattern of the signal received from the user as that signal impinged on the antenna array 138. Referring to FIG. 15, one embodiment of a DOA estimator 128 is shown (which is the same as for DOA estimator 132). Bandpass filtering and downconversion is performed by filter/converter module 210 and signals are routed through an M×L to L×M router 212. The directions of arrival θ are determined by DOA processors 214 using, for example, the Cyclic MUSIC or CLS methods previously described. Referring to FIG. 16, one embodiment of TDOA estimator 135 is shown (which is the same for TDOA estimator 133). Each CCC processor 216 (which implements in a straightforward manner the CCC method previously described) measures the TDOA between a signal on interconnections 129, 131 from an auxiliary antenna and a signal on interconnections 146 from the SCORE-STFDMA processor 142. The two TDOA estimates from a pair of CCC processors interconnected to a particular signal line in interconnections 146 are routed via interconnections 220 to a hyperbola intersect processor 218 that combines the two TDOA estimates to form a DOA estimate as previously described in conjunction with the description of the CCC method. The resulting DOA estimates from the plurality of hyperbola intersect processors 218 are routed out of TDOA estimator 135 on interconnections 141. For the purpose of comparing the potential increase in capacity due to the SCORE-STFDMA method of the present invention relative to the analog FM-FDMA, TDMA, and CDMA schemes previously described, consider a total system-bandwidth of B t =1.25 Mhz. In the following comparison, the number of channels needed by each user in the analog FM-FDMA, TDMA, and CDMA schemes is two (one for transmission and one for reception), and one channel is needed by each user in the present invention because transmission and reception are multiplexed in time. With FM-FDMA, using a channel bandwidth of 30 Khz, 2 channels per user, and a cell reuse factor of 7 yields 3 users per cell. With TDMA, using a channel bandwidth of 30 Khz with three time slots for TDMA, 2 channels per user, and a cell reuse factor of 4 yields 15 users per cell. With CDMA, using 2 channels per user, a frequency reuse factor of 1, sectorization of 3, and voice activity factor of 3/8 yields 120 channels per cell or 60 users per cell. With the SCORE-STFDMA method of the present invention, using a channel bandwidth of 32 Khz, 1 channel per user, a cell reuse factor of 3, and a carrier separation of 1 Khz yields up to 385 users per cell. Decreasing the carrier separation to 500 Hz allows up to 770 users per cell at the expense of doubling the number of antennas. By decreasing the frequency reuse factor from three to one, the user capacity would triple. Accordingly, it will be seen that this invention provides for significant increases in user capacity of radio communications systems by space, time and frequency multiplexing of communications signals. The spatial filtering method of the present invention blindly adapts an array of antennas in accordance with the reception pattern of a signal received from a mobile or portable unit by restoring its spectral coherence. To accomplish this, the signal is correlated with a time and frequency shifted version of itself. The resultant weighting factors that realize the reception pattern of the signal are also applied to the signal to be transmitted to the mobile or portable unit, whereby the reception pattern of the user's signal is reproduced in the radiation pattern of the signal transmitted to the user. This results in radiation of maximum power to the user and minimum power to unintended users, by combining directivity with multipath radiation. Although the description above contains many specificities, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the presently preferred embodiments of this invention. Thus the scope of this invention should be determined by the appended claims and their legal equivalents.

A method and apparatus for spatial multiplexing of spectrally overlapping communications signals which does not require use of a training signal, computationally intensive direction-finding methods, or antenna calibration is presented. An adaptive antenna array at a base station is used in conjunction with signal processing through self coherence restoral to separate the temporally and spectrally overlapping signals of users that arrive from different specific locations within the locale and to mitigate multipath fading and shadowing at the base station and, by reciprocity, to transmit directively to minimize interfering signals arriving at the mobile (or portable or stationary) units and to mitigate multipath fading and shadowing at the mobile units. The radiation pattern of transmitted signal is matched to the adapted reception pattern of the signal received at the base station. BACKGROUND OF THE INVENTION The Government has rights in this invention pursuant to Grant No. MIP-88-12902 awarded by the National Science Foundation.

FIELD OF INVENTION [0001] The present invention relates to novel renin inhibitors of general formula (1), novel intermediates involved in their synthesis, their pharmaceutically acceptable salts and pharmaceutical compositions containing them. The present invention also relates to a process of preparing compounds of general formula (1), their tautomeric forms, their pharmaceutically acceptable salts, pharmaceutical compositions containing them, and novel intermediates involved in their synthesis. [0000] BACKGROUND TO THE INVENTION [0002] In the renin-angiotensin system (RAS) the biologically active angiotensin II (Ang II) is generated by a two-step mechanism. The highly specific enzyme renin cleaves angiotensinogen to angiotensin I (Ang I), which is then further processed to Ang II by the less specific angiotensin-converting enzyme (ACE). Ang II is known to work on at least two receptor subtypes called AT1 and AT2. Whereas AT1 seems to transmit most of the known functions of Ang II, the role of AT2 is still unknown. [0003] Modulation of the RAS represents a major advance in the treatment of cardiovascular diseases. ACE inhibitors and AT1 blockers have been accepted to treat hypertension (Waeber B. et al, “The renin-angiotensin system: role in experimental and human hypertension”, in Birkenhager W. H., Reid J. L. (eds): Hypertension, Amsterdam, Elsevier Science Publishing Co, 1996, 489-519; Weber M. A., Am. J. Hypertens., 1992, 5, 247S). In addition, ACE inhibitors are used for renal protection (Rosenberg M. E. et al, Kidney International, 1994, 45, 403; Breyer J. A. et al. Kidney International, 1994, 45, S156), in the prevention of congestive heart failure (Vaughan D. E. et al, Cardiovasc. Res., 1994, 28, 159; Fouad-Tarazi F. et al., Am. J. Med, 1988, 84 (Suppl. 3A), 83) and myocardial infarction (Pfeffer M. A. et al, N. Engl. J. Med., 1992, 327, 669). [0004] Interest in the development of renin inhibitors is the specificity of renin (Kleinert H. D., Cardiovasc. Drugs, 1995, 9, 645). The only substrate known for renin is angiotensinogen, which can only be processed (under physiological conditions) by renin. In contrast, ACE can also cleave bradykinin besides Ang I and can be by-passed by chymase, a serine protease (Husain A., J. Hypertens., 1993, 11, 1 155). In patients inhibition of ACE thus leads to bradykinin accumulation causing cough (5-20%) and potentially life-threatening angioneurotic edema (0.1-0.2%) (Israili Z. H. et al, Annals of Internal Medicine, 1992, 117, 234). Chymase is not inhibited by ACE inhibitors. Therefore, the formation of Ang II is still possible in patients treated with ACE inhibitors. Blockade of the AT1 receptor (e.g. by losartan) on the other hand overexposes other AT-receptor subtypes (e.g. AT 2 ) to Ang II, whose concentration is significantly increased by the blockade of AT1 receptors. In summary, renin inhibitors are expected to demonstrate a different pharmaceutical profile than ACE inhibitors and AT1 blockers with regard to efficacy in blocking the RAS and in safety aspects. Only limited clinical experience (Azizi M. et al., J. Hypertens., 1994, 12, 419; Neutel J. M. et al, Am. Heart, 1991, 122, 1094) has been created with renin inhibitors because of their insufficient oral activity due to their peptidomimetic character (Kleinert H. D., Cardiovasc. Drugs, 1995, 9, 645). The clinical development of several compounds has been stopped because of this problem together with the high cost of goods. One compound containing four chiral centers has entered clinical trials (Rahuel J. et al. Chem. Biol., 2000, 7, 493; Mealy N. E., Drugs of the Future, 2001, 26, 1139). Thus, renin inhibitors with good oral bioavailability and long duration of action are required. The first non-peptide renin inhibitors were described which show high in vitro activity (Oefner C. et al, Chem. Biol, 1999, 6, 127; Patent Application WO97/09311; Marki H. P. et al., 11 Farmaco, 2001, 56, 21). Recently amine based non-peptidic renin inhibitors have been disclosed in WO 2007099509, having the following general structure [0000] [0000] wherein R 1 represents C 1-7 alkyl or cycloalkyl group preferably cycloalkyl such as cyclopropyl groups and in WO 2007009250 having the following general formula [0000] [0000] wherein R 2 is selected from group H, C 1-6 alkyl, C 2-6 alkenyl, C 1-6 alkoxy, CF 3 , CH 2 CF 3 groups. Compounds disclosed in both the applications were reported to show potency in nanomolar range. [0005] The present invention relates to the identification of renin inhibitors of a non-peptidic nature and of low molecular weight. Described are orally active renin inhibitors of long duration of action which are active in indications beyond blood pressure regulation where the tissular renin-chymase system may be activated leading to pathophysiologically altered local functions such as renal, cardiac and vascular remodeling, atherosclerosis, and possibly restenosis. So, the present invention describes these non-peptidic renin inhibitors SUMMARY OF THE INVENTION [0006] The present invention describes a group of novel compounds as renin inhibitors useful for the treatment cardiovascular events, renal insufficiency and other related diseases. The novel compounds are defined by the general formula (1) below: [0000] [0007] The compounds of the present invention are useful in the treatment of the human or animal body, by regulating renin levels. The compounds of this invention are therefore suitable for the treatment of cardiovascular events, renal insufficiency other related diseases EMBODIMENTS OF THE PRESENT INVENTION [0008] The main objective of the present invention thus is to provide novel compounds of general formula (1), novel intermediates involved in their synthesis, their pharmaceutically acceptable salts, and pharmaceutical compositions containing them or their mixtures as therapeutic agents. [0000] [0009] In an embodiment is provided processes for the preparation of novel compounds of general formula (1), novel intermediates involved in their synthesis, their pharmaceutically acceptable salts, and pharmaceutical compositions containing them. [0010] In another embodiment is provided pharmaceutical compositions containing compounds of general formula (1), their pharmaceutically acceptable salts, comprising pharmaceutically acceptable carriers, solvents, diluents, excipients and other media normally employed in their manufacture. [0011] In a further embodiment is provided the use of the novel compounds of the present invention as blood pressure regulating agents, by administering a therapeutically effective & non-toxic amount of the compounds of formula (1) or their pharmaceutically acceptable compositions to the mammals. DETAILED DESCRIPTION [0012] The present invention therefore discloses renin inhibitors of formula (I) below [0000] wherein m is an integer selected from 1 to 4; Z represents either a bond or —CH 2 —; X and Y are each independently selected from the group comprising of —CH 2 —, O, and S(O) p ; p in each instance in which it occur is independently 0, 1, 2; ‘A’ is an optionally substituted aryl or a 5-6 membered heterocyclic ring containing 1 to 3 heteroatom selected from O, S, and N, wherein ‘A’ may be substituted with one, two, three or four substituents independently selected from the group comprising of OH, CN, halogen, N 3 , NO 2 , COOH, OCF 2 H, CF 3 , C 1 -C 6 alkyl, C 2 -C 6 alkenyl, C 1 -C 6 alkoxy, C(O)C 1 -C 6 alkyl and S(O) p C 1 -C 6 alkyl, (CH 2 ) 1-2 Oalkyl groups; Preferred group representing ‘A’ may be selected from phenyl, benzyl, piperidinyl groups; Q represents carbon or nitrogen atoms; ‘B’ represents a saturated, unsaturated or partly unsaturated single or fused heterocyclic ring which may optionally contain one or more additional heteroatoms selected from nitrogen, oxygen or sulphur or may comprise an —SO— or an —SO 2 -group. When the heterocyclic ring as defined above comprises one or more nitrogen atom, such nitrogen atom may optionally be substituted with optionally substituted groups selected from C 1 -C 8 -alkyl, C 1 -C 8 -alkanoyl, aryl or heterocyclic group. When ‘B’ represents a fused ring then the ring system preferably contains 9-16 member heterocyclic groups. The heterocycle ‘B’, as defined above, may optionally be substituted with groups selected from halogen, hydroxyl, oxide, oxo, cyano, optionally substituted groups selected from haloalkyl, haloalkoxy, C 1 -C 8 -alkyl, C 1 -C 8 -alkoxy, C 1 -C 8 -alkoxy-C 1 -C 8 -alkyl, C 1 -C 8 -alkoxy-C 1 -C 8 -alkoxy, C 1 -C 8 -alkoxycarbonylamino, C 1 -C 8 -alkylcarbonylamino, C 1 -C 8 -alkylamino, N,N-di-C 1 -C 8 -alkylamino, aryl-C 0 -C 4 -alkyl, aryloxy-C 0 -C 4 -alkyl, aryl-C 0 -C 4 -alkyl-C 1 -C 8 -alkoxy, aryloxy-C 0 -C 4 -alkyl-C 1 -C 8 -alkoxy, heterocyclyl-C 0 -C 4 -alkyl, heterocyclyloxy-C 0 -C 4 -alkyl, heterocyclyl-C 0 -C 4 -alkyl-C 1 -C 8 -alkoxy or heterocyclyloxy-C 0 -C 4 -alkyl-C 1 -C 8 -alkoxy groups; [0018] Preferred groups representing ‘B’ selected to form an optionally substituted 1,2,3,4-tetrahydroquinoline, 1,2,3,4-tetrahydroisoquinoline, piperidine, morpholine, pyrrolidine, piperazine, indoline and indole & their suitable derivatives; R 1 at each occurrence independently represents hydrogen, halogen, cyano, optionally substituted C 1 -C 6 alkyl, C 1 -C 6 alkoxy groups; ‘s’ represents integers from 0, 1, 2 and 3; [0019] R 2 , R 3 may be same or different and independently selected from the group comprising of hydrogen, optionally substituted C 1 -C 6 alkyl, C 1 -C 6 alkoxy, C(O)R b , C(O)NR c R d groups; R b is selected from the group comprising of hydrogen, optionally substituted C 1 -C 6 alkyl, C 1 -C 6 alkoxy groups; [0020] R e and R d are independently selected from the groups comprising hydrogen, optionally substituted C 1 -C 6 alkyl, unsubstituted or substituted aryl groups; [0021] As used herein, the term “heterocycle” or “heterocyclic system” is intended to mean a stable 5- to 8-membered monocyclic or bicyclic or a 9- to 16-membered polycyclic heterocyclic ring which may be saturated, partially saturated or unsaturated, and which consists of carbon atoms and further comprises from 1 to 4 heteroatoms independently selected from the group consisting of N, O and S and including any bicyclic group in which any of the above-defined heterocyclic rings is fused to a benzene ring. The term heterocycle is intended to include both aromatic as well as non-aromatic ring system. The nitrogen and sulfur heteroatoms may optionally be oxidized. The heterocyclic ring may be attached to its pendant group at any heteroatom or carbon atom which results in a stable structure. The heterocyclic rings described herein may be substituted on carbon or on a nitrogen atom if the resulting compound is stable. If specifically noted, nitrogen in the heterocycle may optionally be quaternized. It is preferred that when the total number of S and O atoms in the heterocycle exceeds 1, then these heteroatoms are not adjacent to one another. It is preferred that the total number of S and O atoms in the heterocycle is not more than 1. As used herein, the term “aromatic heterocyclic system” is intended to mean a stable 5- to 7-membered monocyclic or bicyclic or 9- to 16-membered polycyclic heterocyclic aromatic ring which consists of carbon atoms and from 1 to 4 heteroatoms independently selected from the group consisting of N, O and S. It is preferred that the total number of S and O atoms in the aromatic heterocycle is not more than 1. [0022] Examples of heterocycles include, but are not limited to, acridinyl, azocinyl, benzimidazolyl, benzofuranyl, benzothiofuranyl, benzothiophenyl, benzoxazolyl, benzthiazolyl, benztriazolyl, benztetrazolyl, benzisoxazolyl, benzisothiazolyl, benzimidazolinyl, carbazolyl, 4aH-carbazolyl, carbolinyl, chromanyl, chromenyl, cinnolinyl, decahydroquinolinyl, 2H,6H-1,5,2-dithiazinyl, dihydrofuro[2,3-b]tetrahydrofuran, furanyl, furazanyl, imidazolidinyl, imidazolinyl, imidazolyl, 1H-indazolyl, indolenyl, indolinyl, indolizinyl, indolyl, 3H-indolyl, isobenzofuranyl, isochromanyl, isoindazolyl, isoindolinyl, isoindolyl, isoquinolinyl, isothiazolyl, isoxazolyl, methylenedioxyphenyl, morpholinyl, naphthyridinyl, octahydroisoquinolinyl, oxadiazolyl, 1,2,3-oxadiazolyl, 1,2,4-oxadiazolyl, 1,2,5-oxadiazolyl, 1,3,4-oxadiazolyl, oxazolidinyl, oxazolyl, oxazolidinyl, pyrimidinyl, phenanthridinyl, phenanthrolinyl, phenazinyl, phenothiazinyl, phenoxathiinyl, phenoxazinyl, phthalazinyl, piperazinyl, piperidinyl, pteridinyl, purinyl, pyranyl, pyrazinyl, pyrazolidinyl, pyrazolinyl, pyrazolyl, pyridazinyl, pyridooxazole, pyridoimidazole, pyridothiazole, pyridinyl, pyridyl, pyrimidinyl, pyrrolidinyl, pyrrolinyl, 2H-pyrrolyl, pyrrolyl, quinazolinyl, quinolinyl, 4H-quinolizinyl, quinoxalinyl, quinuclidinyl, tetrahydrofuranyl, tetrahydroisoquinolinyl, tetrahydroquinolinyl, 6H-1,2,5-thiadiazinyl, 1,2,3-thiadiazolyl, 1,2,4-thiadiazolyl, 1,2,5-thiadiazolyl, 1,3,4-thiadiazolyl, thianthrenyl, thiazolyl, thienyl, thienothiazolyl, thienooxazolyl, thienoimidazolyl, thiophenyl, triazinyl, 1,2,3-triazolyl, 1,2,4-triazolyl, 1,2,5-triazolyl, 1,3,4-triazolyl, and xanthenyl. Also included are fused ring and Spiro compounds containing, for example, the above heterocycles. [0023] Suitable substituents wherever applicable includes, but are not limited to the following radicals, alone or in combination with other radicals, hydroxyl, oxo, halo, thio, nitro, amino, alkyl, alkoxy, haloalkyl or haloalkoxy groups; [0024] The term “substituted,” as used herein, means that any one or more hydrogens on the designated atom is replaced with a selection from the indicated group, provided that the designated atom's normal valency is not exceeded, and that the substitution results in a stable compound. [0025] In a further embodiment the groups, radicals described above may be selected from: the “alkyl” group used either alone or in combination with other radicals, denotes a linear or branched radical containing one to six carbons, selected from methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, amyl, t-amyl, n-pentyl, n-hexyl, and the like; The term “alkenyl” used herein, either alone or in combination with other radicals, denotes a linear or branched radical containing two to twelve carbons; such as vinyl, allyl, 2-butenyl, 3-butenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, 2-hexenyl, 3-hexenyl, 4-hexenyl, 5-hexenyl, 2-heptenyl, 3-heptenyl, 4-heptenyl, 5-heptenyl, 6-heptenyl and the like. The term “alkenyl” includes dienes and trienes of straight and branched chains; The term “alkoxy” used herein, either alone or in combination with other radicals, denotes a radical alkyl, as defined above, attached directly to an oxygen atom, such as methoxy, ethoxy, n-propoxy, iso-propoxy, n-butoxy, t-butoxy, iso-butoxy, pentyloxy, hexyloxy, and the like; The term “halo” or “halogen” used herein, either alone or in combination with other radicals, such as “haloalkyl”, “perhaloalkyl” etc, refers to a fluoro, chloro, bromo or iodo group. The term “haloalkyl” denotes an alkyl radical, as defined above, substituted with one or more halogens; such as fluoromethyl, difluoromethyl, trifluoromethyl, fluoroethyl, difluoroethyl, trifluoroethyl, mono or polyhalo substituted methyl, ethyl, propyl, butyl, pentyl or hexyl groups. The term “haloalkoxy” denotes a haloalkyl, as defined above, directly attached to an oxygen atom, such as fluoromethoxy, chloromethoxy, fluoroethoxy chloroethoxy groups, and the like. The term “aryl” refers to aromatic monocyclic ring system. Suitable aryl group include phenyl, naphthyl and the like. [0031] The term “C 0 ” as employed in expressions such as “C 0 -C 4 alkyl” means a direct covalent bond. Similarly, when an integer defining the presence of certain number of atoms in a group is equal to zero, it means that the atom adjacent thereto is connected directly by a bond. [0032] The compound of the present invention may have chiral centers, e.g. one chiral center [providing for two stereoisomer, (R) and (S)], or two chiral centers [providing up to four stereoisomers (R,R), (S,S), (R,S), (S,R)]. This invention includes all the optical isomers and mixture thereof. Unless specifically mentioned otherwise, reference to one isomer applies to any of the possible isomers. Whenever the isomeric composition is unspecified, all the possible isomers are included. [0033] The present invention also relates to pro-drugs of a compound of formula (1) that convert in vivo to the compound of formula (1) as such. Any reference to a compound of formula (1) is therefore to be understood as referring also to the corresponding pro-drugs of the compound of formula (1), as appropriate and expedient. List of Abbreviation [0000] Boc: t-butyloxycarbonyl DMF: Dimethyl formamide DMSO: Dimethyl sulfoxide THF: Tetrahydrofuran DCM: Dichloromethane EDAC.HCl: N-(3-Dimethyl aminopropyl)-N′-ethyl carbodiimide hydrochloride, HOBT: 1-Hydroxy benzotriazole TFA: Trifluoro acetic acid DCC: Dicyclohexylcarbodiimide DIEA: Disopropyl ethyl amine EtOAc: Ethyl acetate h: Hour(s) min: minute(s) t Ret : Retention time [0048] Suitable groups and substituents on the groups may be selected from those described anywhere in the specification. [0049] Particularly useful compounds may be selected from 3-Amino-1-(3,4-dihydro-2H-quinolin-1-yl)-2-{4-[2-(2,5-dimethyl-phenoxy)-ethoxy]-benzyl}-propan-1-one; 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-(3,4-dihydro-2H-quinolin-1-yl)-propan-1-one; 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-(3,4-dihydro-1H-isoquinolin-2-yl)-propan-1-one; 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-(2,3-dihydro-benzo[1,4]oxazin-4-yl)-propan-1-one; 3-Amino-1-(6-chloro-3,4-dihydro-2H-quinolin-1-yl)-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-propan-1-one; 3-Amino-1-(6-bromo-3,4-dihydro-2H-quinolin-1-yl)-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-propan-1-one; 3-Amino-1-(7,8-dichloro-3,4-dihydro-2H-quinolin-1-yl)-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-propan-1-one; 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-(8-methoxy-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one; 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-(7,8-dimethyl-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one; 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-(6-methyl-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one; 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-(8-fluoro-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one; 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-piperidin-1-yl-propan-1-one; 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-(6-methoxy-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one; 3-Amino-1-(6,8-dichloro-3,4-dihydro-2H-quinolin-1-yl)-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-propan-1-one; 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-(6-trifluoromethyl-3,4-dihydro-2H -quinolin-1-yl)-propan-1-one; 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-(6-trifluoromethyl-3,4-dihydro-2H -quinolin-1-yl)-propan-1-one hydrochloride; 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-(6-trifluoromethyl-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one hemifumarate; 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-(6-methyl-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one; 2-Aminomethyl-3-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-phenyl}-1-(6,7-dimethoxy-3,4-dihydro-1H-isoquinolin-2-yl)-propan-1-one; 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-(4-methyl-piperidin-1-yl)-propan-1-one; 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-(4-pyrimidin-2-yl-piperazin-1-yl)-propan-1-one; 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-(6-fluoro-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one; 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-[4-(2-methoxy-ethoxy)-piperidin-1-yl]-propan-1-one; 2-Aminomethyl-3-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-phenyl}-1-(4-methyl-piperazin-1-yl)-propan-1-one; 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-pyrrolidin-1-yl-propan-1-one; 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-[6-(3-methoxy-propoxy)-3,4-dihydro-2H-quinolin-1-yl]-propan-1-one; 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-morpholin-4-yl-propan-1-one hydrochloride; 2-Aminomethyl-3-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-phenyl}-1-(3-methoxymethyl-piperidin-1-yl)-propan-1-one hydrochloride; 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-(6-trifluoromethoxy-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one hydrochloride; 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-[6-(2,2,2-trifluoro-ethoxy)-3,4-dihydro-2H-quinolin-1-yl]-propan-1-one hydrochloride; 1-(2-Aminomethyl-3-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-phenyl}-propionyl)-pyrrolidine-2-carboxylic acid methyl ester hydrochloride; 2-Aminomethyl-3-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-phenyl}-1-(3-methoxy-piperidin-1-yl)-propan-1-one hydrochloride; 3-Amino-2-{4-[2-(2,6-dichloro-phenoxy)-ethoxy]-benzyl}-1-(6-trifluoromethyl-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one hydrochloride; 3-Amino-2-{4-[2-(2,6-dichloro-phenoxy)-ethoxy]-benzyl}-1-(6-trifluoromethoxy-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one hydrochloride; 3-Amino-2-{4-[2-(2-chloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-(6-trifluoromethyl-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one; 3-Amino-2-{4-[2-(2,6-difluoro-phenoxy)-ethoxy]-benzyl}-1-(6-trifluoromethyl-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one hydrochloride; 3-Amino-2-{4-[2-(2,6-difluoro-phenoxy)-ethoxy]-benzyl}-1-(6-fluoro-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one hydrochloride; 3-Amino-2-{4-[2-(2,4-difluoro-phenoxy)-ethoxy]-benzyl}-1-(6-trifluoromethyl-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one hydrochloride; 3-Amino-2-{4-[2-(2,4-dichloro-phenoxy)-ethoxy]-benzyl}-1-(6-fluoro-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one hydrochloride; 3-Amino-2-{4-[2-(2,4-dichloro-phenoxy)-ethoxy]-benzyl}-1-(6-trifluoromethyl-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one hydrochloride chloride; [0090] 3-Amino-2-{4-[2-(4-chloro-2-fluoro-phenoxy)-ethoxy]-benzyl}-1-(6-fluoro-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one hydrochloride; 3-Amino-2-{4-[2-(4-chloro-2-fluoro-phenoxy)-ethoxy]-benzyl}-1-(6-trifluoromethyl-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one hydrochloride; 3-Amino-2-{6-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-pyridin-3-ylmethyl}-1-(6-trifluoromethyl-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one; 2-Aminomethyl-3-{6-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-pyridin-3-yl}-1-piperidin-1-yl-propan-1-one; 2-Aminomethyl-3-{6-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-pyridin-3-yl}-1-(3,4-dihydro-2H-quinolin-1-yl)-propan-1-one; 3-Amino-2-{6-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-pyridin-3-ylmethyl}-1-(6-fluoro-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one hydrochloride; 2-Aminomethyl-3-{4-[3-(2,6-dichloro-4-methyl-phenoxy)-propoxy]-phenyl}-1-(3,4-dihydro-2H-quinolin-1-yl)-propan-1-one; 3-Amino-1-(6-fluoro-3,4-dihydro-2H-quinolin-1-yl)-2-{4-[3-(2-methoxy-benzyloxy)-propoxy]-benzyl}-propan-1-one; 3-Amino-2-{4-[3-(2-methoxy-benzyloxy)-propoxy]-benzyl}-1-(6-trifluoromethyl-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one; 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-3-methoxy-benzyl}-1-(3,4-dihydro-2H-quinolin-1-yl)-propan-1-one hydrochloride; 1-(3-(6-Chloro-3,4-dihydro-2H-quinolin-1-yl)-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-3-oxo-propyl)-3-phenyl-urea; [2-{4-[2-(2,6-Dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-3-oxo-3-(6-trifluoromethyl-3,4-dihydro-2H-quinolin-1-yl)-propyl]-carbamic acid tert-butyl ester; 3-Amino-2-{4-[2-(2,6-dichloro-phenyl)-ethoxy]-benzyl}-1-(6-trifluoromethyl-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one hydrochloride; 3-Amino-2-{4-[2-(2,6-dichloro-phenyl)-ethoxy]-benzyl}-1-(6-fluoro-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one hydrochloride; 3-Amino-1-(6-tert-butyl-3,4-dihydro-2H-quinolin-1-yl)-2-{4-[2-(2,6-dichloro-phenoxy)-ethoxy]-benzyl}-propan-1-one hydrochloride; 3-Amino-2-{4-[2-(piperidin-4-yloxy)-ethoxy]-benzyl}-1-(6-trifluoromethyl-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one hydrochloride; [1-(3-Amino-2-{4-[2-(2,6-dichloro-phenoxy)-ethoxy]-benzyl}-propionyl)-pyrrolidin-3-yl]-carbamic acid tert-butyl ester; 2-Aminomethyl-3-{4-[2-(2,6-dichloro-phenoxy)-ethoxy]-phenyl}-1-(2,3-dihydro-indol-1-yl)-propan-1-one hydrochloride; 3-Amino-2-{4-[2-(2,4-difluoro-phenoxy)-ethoxy]-benzyl}-1-(6-trifluoromethoxy-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one hydrochloride; 3-Amino-2-{4-[2-(2,4-difluoro-phenoxy)-ethoxy]-benzyl}-1-piperidin-1-yl-propan-1-one hydrochloride; 3-Amino-2-{4-[2-(2,4-difluoro-phenoxy)-ethoxy]-benzyl}-1-(3,4-dihydro-2H-quinolin-1-yl)-propan-1-one hydrochloride; [0111] Following compounds can be synthesized by following the procedure mentioned herein along with suitable modifications/alterations etc. which are within the scope of the person skilled in the art. 3-Amino-2-{4-[2-(2,4-difluoro-phenoxy)-ethoxy]-benzyl}-1-(2,3-dihydro-indol-1-yl)-propan-1-one hydrochloride; 3-Amino-2-{4-[2-(2,6-dichloro-phenoxy)-ethoxy]-benzyl}-1-(3-methoxymethyl-piperidin-1-yl)-propan-1-one hydrochloride; 3-Amino-2-{4-[2-(2,6-dichloro-phenoxy)-ethoxy]-benzyl}-1-piperidin-1-yl-propan-1-one hydrochloride; 1-(3-Amino-2-{4-[2-(2,6-dichloro-phenoxy)-ethoxy]-benzyl}-propionyl)-pyrrolidine-2-carboxylic acid methyl ester hydrochloride; 3-Amino-2-{4-[2-(2,6-dichloro-phenoxy)-ethoxy]-benzyl}-1-(3,4-dihydro-2H-quinolin-1-yl)-propan-1-one hydrochloride; 3-Amino-2-{4-[2-(2,6-dichloro-phenoxy)-ethoxy]-benzyl}-1-morpholin-4-yl-propan-1-one hydrochloride; 3-Amino-2-{4-[2-(2,6-dichloro-phenoxy)-ethoxy]-benzyl}-1-(6-methoxy-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one hydrochloride; 3-Amino-2-{4-[2-(2,6-dichloro-phenoxy)-ethoxy]-benzyl}-1-pyrrolidin-1-yl-propan-1-one hydrochloride; 2-Aminomethyl-3-{6-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-pyridin-3-yl}-1-(3-methoxymethyl-piperidin-1-yl)-propan-1-one hydrochloride; 2-Aminomethyl-3-{6-[2-(2,6-dichloro-phenoxy)-ethoxy]-pyridin-3-yl}-1-(3-methoxymethyl-piperidin-1-yl)-propan-1-one hydrochloride; (R)-2-Aminomethyl-3-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-phenyl}-1-(2-methoxymethyl-pyrrolidin-1-yl)-propan-1-one hydrochloride; (S)-2-Aminomethyl-3-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-phenyl}-1-(2-methoxymethyl-pyrrolidin-1-yl)-propan-1-one hydrochloride; [0124] The compounds of the present invention may be prepared using the methods described below, together with conventional technique known to those skilled in the art of organic synthesis, or variation thereon as appreciated by those skilled in the art. Refereed method included, but not limited to those described below, where all symbols are define earlier. [0000] [0125] Propionitrile derivatives of formula (2), where all symbols are defined earlier, may be synthesized by reacting cyclic amine derivative (B), where all symbols are as described earlier with cyano acetic acid using carboxyl groups activating agents such as EDAC.HCl, DCC and the like in the presence of an additive like HOBT and base like triethyl amine or diisopropylethylamine in solvent(s) like dimethyl formamide or dichloromethane at temperature 0-25° C. Reacting aldehyde derivative of formula (3) with the propionitrile derivative of formula (2) as prepared above, in the presence of an organic base such as triethyl amine, piperidine, imidazole, ethyl diisopropyl amine and the like gives the acrylonitrile derivative of formula (4). The reaction may be performed at 25-110° C. and solvent(s) may be selected from benzene, toluene and the like or their suitable mixtures. [0126] The reduction of double bond in acrylonitrile derivative of formula (4) as prepared above can be accomplished using hydrogenation or using suitable reducing agents like sodium borohydride, sodium cyanoborohydride, lithium aluminum hydride and the like to obtain nitrile derivative of formula (5). The reaction may be performed at −20 to +20° C. and suitable solvent(s) may be suitable ethereal solvents like diethyl ether, tetrahydrofuran and the like or halogenated solvent(s) like dichloromethane, dichloroethane and the like or suitable mixture thereof. Method A [0127] [0128] The reduction of cyano group in nitrile derivative of formula (5) as prepared earlier can be accomplished using suitable hydrogenation techniques or with suitable reducing agents such as cobalt(II) chloride hexahydrate-NaBH 4 , nickel(II)chloride dihydrate-NaBH 4 and the like to get amine compound of formula (1). The reaction may be performed at −20 to +20° C. and solvents may be suitable ethereal solvent(s) like diethyl ether, tetrahydrofuran and the like or suitable protic solvent(s) like methanol, ethanol or mixture thereof. Method B [0129] [0130] The reduction of cyano group in the nitrile derivative of formula (5) as prepared earlier can be accomplished using suitable hydrogenation techniques to get the corresponding amine derivatives and the protection of amine functionality so obtained, can be accomplished by adding suitable amine protecting groups like Boc anhydride to get protected amine compound of formula (6). The reaction may be performed at ambient temperature and solvents may be suitable ethereal solvent(s) like diethyl ether, tetrahydrofurane and like or suitable protic solvent(s) like methanol, ethanol or their suitable mixtures. Removal of amine protecting group in compound (6) can be accomplished using suitable amino deprotecting agents like dioxane.HCl, methanolic.HCl, DCM-TFA and like to afford amine hydrochloride compound (1A). The reaction may be performed at 0 to 25° C. [0000] [0131] Urea derivative (1B), where all symbols are defined earlier, may be synthesized by reacting amine derivative (1), where all the symbols are define earlier, with an appropriate isocyanate in chlorinating solvent(s) like dichloro methane, dichloro ethane and like. The base used may be any suitable base(s) such as triethylamine, diisopropyl ethyl amine and like. The reaction may be performed at temperature 0 to 40° C. [0000] [0132] Carbamate derivatives (1C), where all the symbols define earlier, may be synthesized by reacting amine derivative (1), where all the symbols define earlier, with appropriate alkyl or aryl chloro formates in the presence of suitable base(s) like triethyl amine, diisopropyl ethyl amine and like, using chlorinating solvent(s) like dichloromethane and the like or dimethyl formamide. The reaction may be performed at 0 to 100° C. [0133] The pharmaceutically acceptable salts forming a part of this invention may be prepared by treating the compound of formula (1) with suitable acids in suitable solvents by processes known in the art. [0134] It will be appreciated that in any of the above mentioned reactions any reactive group in the substrate molecule may be protected, according to conventional chemical practice. Suitable protecting group in any of the above mentioned reactions are those used conventionally in the art. The methods of formation and removal of such protecting groups are those conventional methods appropriate to the molecule being protected. T. W. Greene and P. G. M. Wits “Protective groups in Organic Synthesis”, John Wiley & Sons, Inc, 1999, 3 rd Ed., 201-245 along with references therein gives such conventional methods and are incorporated herein as references. [0135] The novel compounds of the present invention can be formulated into suitable pharmaceutically acceptable compositions by combining with suitable excipients by technique and processes and concentrations as are well known. [0136] The compounds of formula (1) or pharmaceutical compositions containing them are useful as Renin inhibitors suitable for humans and other warm blooded animals, and may be administered either by oral, topical or parenteral administration. [0137] The pharmaceutical composition is provided by employing conventional techniques. Preferably the composition is in unit dosage form containing an effective amount of the active component, that is, the compounds of formula (1) according to this invention. [0138] The quantity of active component optionally substituted, that is the compounds of formula (1) according to this invention, in the pharmaceutical compositions and unit dosage form thereof may be varied or adjusted widely depending upon the particular application method, the potency of the particular compound and the desired concentration. Generally, the quantity of active component will range from 0.5% to 90% by weight of the composition. [0139] The compounds of the present invention are suitable as Renin inhibitors and are useful in the treatment of hypertension, congestive heart failure, pulmonary hypertension, renal insufficiency, renal ischemia, renal failure, renal fibrosis, cardiac insufficiency, cardiac hypertrophy, cardiac fibrosis, myocardial ischemia, cardiomyopathy, glomerulonephrtis renal colic, complication resulting from diabetes such as nephropathy, vasculopathy, and neuropathy, glaucoma, elevated intraocular pressure, atherosclerosis, restenosis post angioplasty, complications following vascular or cardiac surgery, erectile dysfunction. [0140] The invention is further exemplified by the following examples below, which provides one of the several preferred embodiments of the present invention. These examples are provided merely as representative embodiments and should not be construed to limit the scope of the invention in any way. Preparation: [0141] The following Aldehyde building blocks were synthesized by the process described beneath: [0000] Compound Name Aldehyde 1 4-[2-(2,6-Dichloro-4-methyl-phenoxy)-ethoxy]- benzaldehyde Aldehyde 2 4-[2-(2,5-Dimethyl-phenoxy)-ethoxy]-benzaldehyde Aldehyde 3 4-[2-(2,6-Dichloro-phenoxy)-ethoxy]-benzaldehyde Aldehyde 4 4-[2-(2,6-Difluoro-phenoxy)-ethoxy]-benzaldehyde Aldehyde 5 4-[2-(2,4-Difluoro-phenoxy)-ethoxy]-benzaldehyde Aldehyde 6 4-[2-(2,4-Dichloro-phenoxy)-ethoxy]-benzaldehyde Aldehyde 7 4-[2-(4-Chloro-2-fluoro-phenoxy)-ethoxy]-benzaldehyde Aldehyde 8 6-[2-(2,6-Dichloro-4-methyl-phenoxy)-ethoxy]-pyridine-3- carbaldehyde Aldehyde 9 4-[3-(2,6-Dichloro-4-methyl-phenoxy)-propoxy]- benzaldehyde Aldehyde 10 4-[3-(2-Methoxy-benzyloxy)-propoxy]-benzaldehyde Aldehyde 11 4-[2-(2,6-Dichloro-4-methyl-phenoxy)-ethoxy]-3-methoxy- benzaldehyde Aldehyde 12 4-[2-(2-Chloro-4-methyl-phenoxy)-ethoxy]-benzaldehyde Aldehyde 13 4-[2-(2,6-Dichloro-phenyl)-ethoxy]-benzaldehyde Aldehyde 14 4-[2-(4-Formyl-phenoxy)-ethoxy]-piperidine-1-carboxylic acid tert-butyl ester Aldehyde 1: 4-[2-(2,6-Dichloro-4-methyl-phenoxy)-ethoxy]-benzaldehyde Step 1: 2-(2,6-Dichloro-4-methyl-phenoxy)-ethanol [0142] 2,6-Dichloro-4-methyl phenol (1 eq), ethylene carbonate (1.5 eq) and piperidine (0.1 eq) were combined and heated at 140° C. for 6 h to afford the title compound as brown oil. Step 2: Aldehyde 1 [0143] 2-(2,6-Dichloro-4-methyl-phenoxy)-ethanol (1 eq) obtained from step 1 above, and 4-hydroxy benzaldehyde (1 eq) were taken up in 10 v of dry toluene. To this, was then added triphenyl phosphine (1.3 eq) and finally diisopropylazadicarboxylate (1.5 eq) at 0-10° C. [0144] Reaction mixture was allowed to attain room temperature and stirred for 14-18 h. Mixture was diluted with water and compound was extracted with EtOAc. Combined organic layer was washed with brine and dried over sodium sulfate. Filtration and concentration of filtrate in vacuo afforded a yellow semi solid. Purification of the crude product thus obtained by way of flash column chromatography (SiO 2 4:1 (v/v) Hexane:EtOAc) afforded the title compound as white needle. Aldehyde 2: 4-[2-(2,5-Dimethyl-phenoxy)-ethoxy]-benzaldehyde [0145] Prepared similar to the procedure described in Aldehyde 1 but using instead 2,5-dimethyl phenol as starting material. Aldehyde 3: 4-[2-(2,6-Dichloro-phenoxy)-ethoxy]-benzaldehyde [0146] Prepared similar to the procedure described in Aldehyde 1 but using instead 2,6-dichloro phenol as starting material. Aldehyde 4: 4-[2-(2,6-Difluoro-phenoxy)-ethoxy]-benzaldehyde [0147] Prepared similar to the procedure described in Aldehyde 1 but using instead 2,6-difluoro phenol as starting material. Aldehyde 5: 4-[2-(2,4-Difluoro-phenoxy)-ethoxy]-benzaldehyde [0148] Prepared similar to the procedure described in Aldehyde 1 but using instead 2,4-difluoro phenol as starting material. Aldehyde 6: 4-[2-(2,4-Dichloro-phenoxy)-ethoxy]-benzaldehyde [0149] Prepared similar to the procedure described in Aldehyde 1 but using instead 2,4-dichloro phenol as starting material. Aldehyde 7: 4-[2-(4-Chloro-2-fluoro-phenoxy)-ethoxy]-benzaldehyde [0150] Prepared similar to the procedure described in Aldehyde 1 but using instead 2-fluoro-4-chloro phenol as starting material. Aldehyde 8: 6-[2-(2,6-Dichloro-4-methyl-phenoxy)-ethoxy]-pyridine-3-carbaldehyde Step 1: 5-Bromo-2-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-pyridine [0151] To a solution of 2-(2,6-dichloro-4-methyl-phenoxy)-ethanol (1 eq) in dry THF, sodium hydride (3.5 eq) was added at 0° C. Mixture was allowed to warm to room temperature and stirred for 1 h. To this, 2,5-dibromo pyridine (1 eq) was added dropwise and mixture was heated at 90° C. for 2 h. Organic volatiles were removed under reduced pressure. Mixture was diluted with EtOAc. Organic layer was washed with water, brine, dried over sodium sulfate and evaporated under reduced pressure to afford title compound as white solid. Step 2: Aldehyde 8 [0152] n-BuLi (1.15 eq) was added to the mixture of 5-bromo-2-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-pyridine in THF at −40° C. The mixture was stirred for 1-3 h at same temperature and DMF (3 eq) was added. Mixture was stirred for 2-5 h at −40° C. Mixture was allowed to warm to room temperature and stirred at 14-18 h. Mixture was quenched in saturated NH 4 Cl solution and extracted with diethyl ether. Organic layer was washed with brine dried over sodium sulfate, filtered and evaporated in vacuo afforded semi solid. Purification of the crude product thus obtained by the way of flash column chromatography (SiO 2 , 7:3 (v/v) hexane:EtOAc) afforded title compound as white solid. Aldehyde 9: 4-[3-(2,6-Dichloro-4-methyl-phenoxy)-propoxy]-benzaldehyde Step 1: 3-(2,6-Dichloro-4-methyl-phenoxy)-propan-1-ol [0153] 2,6-Dichloro-4-methyl phenol (1 eq), 3-bromo-1-propanol (1.2 eq) and anhydrous K 2 CO 3 (2.5 eq) were mixed in dry acetone (30 v) and heated to refluxed for 4-8 h. [0154] Mixture was quenched in water. Compound was extracted with EtOAc. Combined organic layer was washed with brine, dried over sodium sulfate and evaporated in vacuo to afforded title compound as brown liquid. Step 2: Aldehyde 9 [0155] 3-(2,6-Dichloro-4-methyl-phenoxy)-propan-1-ol (1 eq), 4-hydroxy benzaldehyde (1 eq) were taken in dry toluene (10 v). Triphenyl phosphine (1.3 eq) and diisopropylazadicarboxylate (1.5 eq) was added to this mixture at 0-10° C. Reaction mixture was allowed to attained room temperature and stirred for 14-18 h. Mixture was quenched in water and extracted with EtOAc. Combined organic layer was washed with brine, dried over sodium sulfate, filtered and evaporated in vacuo to afford semi solid compound. Purification of the crude product thus obtained by the way of flash column chromatography (SiO 2 , 4:1 (v/v) Hexane:EtOAc) afforded the title compound as white solid. Aldehyde 10: 4-[3-(2-Methoxy-benzyloxy)-propoxy]-benzaldehyde Step 1: 3-(2-Methoxy-benzyloxy)-propan-1-ol [0156] 2-Methoxy benzyl alcohol (1 eq) was taken in dry DMF and sodium hydride (50%, 2.2 eq) was added to it at 0° C. Mixture was stirred at 25° C. for 1 hr and 3-bromo-1-propanol (1.2 eq) was added to the mixture at 0° C. Mixture was stirred at 25° C. for 2 h and quenched in water. Product was extracted with diethyl ether. Organic layer was washed with water, dried over sodium sulfate, filtered and evaporated in vacuo to afforded oily compound. Purification of crude product thus obtained by the way of flash column chromatography (SiO 2 , 7:3 (v/v) hexane:EtOAc) to afford title compound as colorless oil. Step 2: Aldehyde 10 [0157] 2-Methoxy-benzyloxy)-propan-1-ol (1 eq), 4-hydroxy benzaldehyde (1 eq) and triphenyl phosphine (1.2 eq) were taken in dry toluene (10 v). Diisopropyl azadi carboxylate (1.5 eq) was added to this mixture at 0° C. Mixture was warmed to room temperature and stirred for 14-18 h. Mixture was quenched in water. Organic layer was separated and product was extracted with EtOAc. Combined organic layer was washed with brine, dried over sodium sulfate, filtered and evaporated in vacuo to afforded crude semisolid. Purification of the crude product thus obtained by the way of flash column chromatography (SiO 2 , 3:7 (v/v) Hexane:EtOAc) to afford title compound as off white solid. Aldehyde 11: 4-[2-(2,6-Dichloro-4-methyl-phenoxy)-ethoxy]-3-methoxy-benzaldehyde [0158] Prepared similar to the procedure described in Aldehyde 1 but using instead 3-methoxy-4-hydroxy benzaldehyde in step 2. Aldehyde 12: 4-[2-(2-Chloro-4-methyl-phenoxy)-ethoxy]-benzaldehyde [0159] Prepared similar to the procedure described in Aldehyde 1 but using instead 2-chloro-4-methyl phenol as starting material. Aldehyde 13: 4-[2-(2,6-Dichloro-phenyl)-ethoxy]-benzaldehyde Step 1: 2-(2,6-Dichloro-phenyl)-ethanol [0160] 2,6-Dichloro phenyl acetic acid methyl ester (1 eq) was taken in THF:Water (10:0.1 (v/v) and cooled to 5-10° C. NaBH 4 was added to this mixture and mixture was stirred for 4 h. Mixture was quenched in water and extracted with EtOAc. Organic layer was washed with brine and evaporated in vacuo to afford title compound as thick liquid. Step 2: Aldehyde 13 [0161] Prepared similar to the procedure described in Aldehyde 1, Step 2 but using instead 2-(2,6-dichloro-phenyl)-ethanol as starting material. Aldehyde 14: 4-[2-(4-Formyl-phenoxy)-ethoxy]-piperidine-1-carboxylic acid tert-butyl ester [0162] Prepared similar to the procedure described in Aldehyde 1, Step 2 but using instead 4-(2-hydroxy-ethoxy)-piperidine-1-carboxylic acid tert-butyl ester as starting material. [0163] The cyclic amine building blocks in Table 2 were synthesized as follow [0000] TABLE 2 Compound Name Amine 1 6-Fluoro-1,2,3,4-tetrahydro quinoline Amine 2 6-Chloro-1,2,3,4-tetrahydro quinoline Amine 3 7,8-Dichloro-1,2,3,4,-tetrahydro quinoline Amine 4 8-Methoxy 1,2,3,4-tetrahydro quinoline Amine 5 7,8-Dimethyl-1,2,3,4-tetrahydro quinoline Amine 6 6-Methyl-1,2,3,4-tetrahydro quinoline Amine 7 8-Fluoro-1,2,3,4-tetrahydro quinoline Amine 8 6-Trifluoromethyl-1,2,3,4-tetrahydro quinoline Amine 9 6,8-Dichloro-1,2,3,4-tetrahydroquinoline Amine 10 6-Trifluomethoxy-1,2,3,4-tetrahydro quinoline Amine 11 6-Bromo-1,2,3,4-tetrahydro quinoline Amine 12 6-(2,2,2-Trifluoro-ethoxy)-1,2,3,4-tetrahydro-quinoline hydrochloride Amine 13 6-(3-Methoxy-propoxy)-1,2,3,4-tetrahydro-quinoline hydrochloride Amien 14 3-Methoxymethyl-piperidine hydrochloride Amine 15 3-Methoxy-piperidine hydrochloride Amine 16 4-(2-Methoxy-ethoxy)-piperidine hydrochloride Amine 17 6-tert-Butyl-1,2,3,4-tetrahydro quinoline Amine 1: 6-Fluoro-1,2,3,4-tetrahydro-quinoline Step 1: 6-Fluoro quinoline [0164] Concentrated sulfuric acid (3 eq) was added dropwise to a vigorously stirred mixture of 4-fluoro aniline (1 eq), 1 2 (0.1 eq), in glycerol (1.5 eq) within 0.5 h, wherein the temperature of the mixture rises to 65-70° C. The mixture was then heated to 135-140° C. for 10-12 h giving dark brown forming mixture. The mixture was cooled to room temperature and quenched in ice cooled water. pH of the solution was adjusted to 8 to 9 by adding 25-30% ammonia solution. Aqueous layer was extracted with EtOAc. Organic layer was washed with brine, dried over sodium sulfate and evaporated in vacuo to get crude product. Purification of the crude product thus obtained by the way of flash column chromatography (SiO 2 , 8:2 (v/v) hexane:EtOAc) to afforded title compound as dark red liquid. Step 2: Amine 1 [0165] Sodium cyanoborohydride (3 eq) was added gradually to the solution of 6-fluoro quinoline (1 eq) in glacial acetic acid (3 v) at ambient temperature. After stirring for 6 h the reaction mixture was quenched in water and extracted with EtOAc. The combined organic layers were washed with water, brine and dried over sodium sulfate, filtered and evaporated in vacuo to get crude product. The desired product was purified by column chromatography (SiO 2 , 3:7 hexane:EtOAc) afforded title compound as light yellow liquid. Amine 2: 6-Fluoro-1,2,3,4-tetrahydro-quinoline [0166] Prepared similar to the procedure described in amine 1 but using instead 4-chloro aniline as starting material. Amine 3: 7,8-Dichloro-1,2,3,4-tetrahydro-quinoline [0167] Prepared similar to the procedure described in amine 1 but using instead 2,3-dichloro aniline as starting material. Amine 4: 8-Methoxy-1,2,3,4-tetrahydroquinoline [0168] Prepared similar to the procedure described in amine 1 but using instead 2-methoxy aniline as starting material. Amine 5: 7,8-Dimethyl-1,2,3,4-tetrahydro quinoline [0169] Prepared similar to the procedure described in amine 1 but using instead 2,3-dimethyl aniline as starting material. Amine 6: 6-Methyl-1,2,3,4-tetrahydroquinoline [0170] Prepared similar to the procedure described in amine 1 but using instead 4-methyl quinoline as starting material. Amine 7: 8-Fluoro-1,2,3,4-tetrahydro quinoline [0171] Prepared similar to the procedure described in amine 1 but using instead 2-fluoro quinoline as starting material. Amine 8: 6-Trifluoromethyl-1,2,3,4-tetrahydroquinoline [0172] Prepared similar to the procedure described in amine 1 but using instead 4-trifluoromethylaniline as starting material. Amine 9: 6,8-Dichloro-1,2,3,4-tetrahydro quinoline [0173] Prepared similar to the procedure described in amine 1 but using instead 2,4-dichloro aniline as starting material. Amine 10: 6-Trifluoromethoxy-1,2,3,4-tetrahydro quinoline [0174] Prepared similar to the procedure described in amine 1 but using instead 4-trifluoromethoxy aniline as starting material. Amine 11: 6-Bromo-1,2,3,4-tetrahydro quinoline [0175] Prepared similar to the procedure described in amine 1 but using instead 4-bromo aniline as starting material. Amine 12: 6-(2,2,2-Trifluoro-ethoxy)-1,2,3,4-tetrahydro-quinoline hydrochloride Step 1: 6-Hydroxy-3,4-dihydro-2H-quinoline-1-carboxylic acid tert-butyl ester [0176] 6-Hydroxy-1,2,3,4-tetrahydro quinoline (1 eq), Boc anhydride (1.2 eq) and triethyl amine (1.2 eq) were mixed and heated to refluxed for 2 hr. Mixture was quenched in water and product was extracted with EtOAc to afford title compound as oil. Compound was used directly for the next reaction without purification. Step 2: 6-(2,2,2-Trifluoro-ethoxy)-3,4-dihydro-2H-quinoline-1-carboxylic acid tert-butyl ester [0177] 6-(2,2,2-Trifluoro-ethoxy)-1,2,3,4-tetrahydro-quinoline (1 eq), methanesulfonic acid 2,2,2-trifluoro-ethyl ester (1 eq) and anhydrous K 2 CO 3 were mixed in DMF (5 v) and mixture was heated to 80-100° C. Reaction mixture was quenched in water. Product was extracted with EtOAc; organic layer was washed with brine, dried over sodium sulfate, filtered and evaporated in vacuo to get brown color oily compound. Step 3: Amine 12 [0178] Dioxane.HCl (10%, 2v) was added to 6-(2,2,2-trifluoro-ethoxy)-3,4-dihydro-2H-quinoline-1-carboxylic acid tert-butyl ester (1 eq) and mixture was stirred for 1 h at 0-5° C. Organic volatiles were removed under reduced pressure to afford title compound as brown liquid. Amine 13: 6-(3-Methoxy-propoxy)-1,2,3,4-tetrahydro-quinoline hydrochloride Step 1: 6-Hydroxy-3,4-dihydro-2H-quinoline-1-carboxylic acid tert-butyl ester [0179] Prepared as per the procedure reported in Amine 12 Step 1 Step 2: 6-(3-Methoxy-propoxy)-3,4-dihydro-2H-quinoline-1-carboxylic acid tert-butyl ester [0180] 6-Hydroxy-3,4-dihydro-2H-quinoline-1-carboxylic acid tert-butyl ester (1 eq) obtained from step 1, 1-bromo-3-methoxy-propane (1.1 eq) and anhydrous K 2 CO 3 (1.5 eq) were mixed in DMF (5 v) and heated to 70-80° C. for 2-5 h. Mixture was quenched in water and product was extracted with EtOAc. Combined organic layers were washed with brine, dried over sodium sulfate, filtered and evaporated in vacuo to afford title compound as oil. The crude product was purified by the way of flash column chromatography (SiO 2 , 3:7 (v/v)::Hexane:EtOAc) to afford title compound as light brown liquid. Step 3: Amine 13 [0181] Dioxane.HCl (10%, 2v) was added to 6-(3-methoxy-propoxy)-3,4-dihydro-2H-quinoline-1-carboxylic acid tert-butyl ester (1 eq) and mixture was stirred for 1 h at 0-5° C. Organic volatiles were removed under reduced pressure to afford title compound as brown syrupy liquid. Amine 14: 3-Methoxymethyl-piperidine hydrochloride Step 1: 3-Methanesulfonyloxymethyl-piperidine-1-carboxylic acid tert-butyl ester [0182] N-Boc-3-hydroxymethyl piperidine (1 eq), triethylamine (2 eq) were taken in DCM (10 v). Methane sulfonyl chloride (1.2 eq) was added to the mixture at 0° C. Mixture was stirred at 10° C. for 2-5 h. Reaction mixture was quenched in water. Organic layer was separated washed with brine, dried over sodium sulfate, filtered, and evaporated in vacuo to get title compound as semi solid. Step 2: 3-Methoxymethyl-piperidine-1-carboxylic acid tert-butyl ester [0183] Sodium metal (3 eq) was dissolved in dry methanol (10 v) and 3-methanesulfonyloxy methyl-piperidine-1-carboxylic acid tert-butyl ester (1 eq) was added to this stirred solution at 10° C. Mixture was refluxed form 3 h. Mixture was quenched in water. Product was extracted by EtOAc. Organic layer was washed with water, brine, dried over sodium sulfate, filtered and evaporated in vacuo to afforded title compound as liquid. Step 3: Amine 14 [0184] Dioxane.HCl (10%) was added to 3-methoxymethyl-piperidine-1-carboxylic acid tert-butyl ester (1 eq) and mixture was stirred for 1 h at 0-5° C. Organic volatiles were removed under reduced pressure to afford title compound as yellow solid. Amine 15: 3-Methoxy-piperidine hydrochloride Step 1: 3-Methoxy-piperidine-1-carboxylic acid tert-butyl ester [0185] N-Boc-3-hydroxy piperidine (1 eq) was dissolved in THF (5 v), to this sodium hydride (50%, 2.2 eq) was added at 0° C. Mixture was stirred for lh and methyl iodide (1.2 eq) was added. Mixture was stirred for 2-6 h and diluted with water. Product was extracted with EtOAc. Organic layer was washed with water, brine, dried over sodium sulfate, filtered and evaporated in vacuo to afford title compound as thick liquid. Step 2: Amine 15 [0186] Prepared similar to the procedure described in Amine 14 step 3 but using instead 3-methoxy-piperidine-1-carboxylic acid tert-butyl ester as starting material. Amine 16: 4-(2-Methoxy-ethoxy)-piperidine hydrochloride Step 1: 4-tert-Butoxycarbonylmethoxy-piperidine-1-carboxylic acid tert-butyl ester [0187] N-Boc-4-hydroxy piperidine (1 eq), tetrabutyl ammonium hydrogen sulfate (0.3 eq) and sodium hydroxide (1.2 eq) were taken in toluene and bromo-acetic acid tert-butyl ester (1.8 eq) was added to this mixture. Mixture was allowed to reflux for 4 h. Mixture was quenched in water, organic layer was separated, dried over sodium sulfate, filtered and evaporated in vacuo to afford title compound as off white solid. Step 2: 4-(2-Hydroxy-ethoxy)-piperidine-1-carboxylic acid tert-butyl ester [0188] 4-tert-Butoxycarbonylmethoxy-piperidine-1-carboxylic acid tert-butyl ester (1 eq) was dissolved in dry THF (5 v), to this LiALH 4 (1.2 eq) was added at 0-5° C. and mixture was stirred for 2 h. Mixture was quenched in saturated ammonium chloride solution. Product was extracted with EtOAc. Combined organic layer was washed with brine, dried over sodium sulfate, filtered and evaporated in vacuo to afford title compound as liquid. Crude product obtained was used directly for the next reaction without further purifications. Step 3: 4-(2-Methoxy-ethoxy)-piperidine-1-carboxylic acid tert-butyl ester [0189] 4-(2-Hydroxy-ethoxy)-piperidine-1-carboxylic acid tert-butyl ester (1 eq) was dissolved in DMF (5v), to this NaH (50%, 2.2 eq) was added to this mixture at 5-10° C. followed by methyl iodide (1.2 eq). Mixture was stirred for 2 h at 25° C. and quenched in water. Product was extracted with EtOAc. Organic layer was washed with brine, dried over sodium sulfate, filtered and evaporated in vacuo to afford title compound as thick liquid. Step 4: Amine 16 [0190] Prepared similar to the procedure described in Amine 14 step 3 but using instead 4-(2-methoxy-ethoxy)-piperidine-1-carboxylic acid tert-butyl ester as starting material. Amine 17: 6-tert-butyl-1,2,3,4-tetrahydroquinoline [0191] Prepared similar to the procedure described in amine 1 but using instead 4-tert-butyl aniline as starting material [0192] HPLC Condition. [0193] HPLC column: ODS-(150×4.6)4 u, C-18 [0194] Mobile phase: 0.05% TFA buffer: ACN (Gradient) [0195] Flow rate: 1.0 mL/min [0196] Wavelength: UV at 220 nm Example 1 Preparation of 2-Aminomethyl-1-(3,4-dihydro-2H-quinolin-1-yl)-3-{4-[2-(2,5-dimethyl-phenoxy)-ethoxy]-phenyl}-propan-1-one Step 1: Preparation of 3-(3,4-dihydro-2H-quinolin-1-yl)-3-oxo-propionitrile [0197] To a solution of cyano acetic acid [1 eq] in DMF [5v], was added HOBT [1.3 eq]. To this reaction mixture was added EDAC.HCl [1.2 eq], 1,2,3,4-tetrahydroquinoline [1 eq] and diisopropyl ethylamine [3 eq] under N 2 at 0-5° C. The resulting reaction mixture was stirred at 25° C. for 14-18 h. Mixture was quenched in water. The aqueous layer was extracted with EtOAc. The organic layer was washed with brine, dried over sodium sulfate and concentrated in vacuo to afford light yellow liquid. Purification of crude product was thus obtained by the way of column chromatography (SiO 2 , Hexane to 1:10 (v/v) EtOAc:hexane) to get sticky solid. The title compound was characterized by spectral analysis. ESI-MS 200.8 (M+H) + Step 2: 2-(3,4-dihydro-2H-quinoline-1-carbonyl)-3-{4-[2-(2,5-dimethyl-phenoxy)-ethoxy]-phenyl}-acrylonitrile [0198] 4-[2-(2,5-Dimethyl-phenoxy)-ethoxy]-benzaldehyde [1 eq] and 3-(3,4-dihydro-2H-quinolin-1-yl)-3-oxo-propionitrile [1 eq] obtained from step 1, was dissolved in toluene. To this solution was added few drops of piperidine. Dean-Stark apparatus was attached to the reaction assembly. The resulting pale yellow solution was heated to reflux for 5 h and volatiles were removed in vacuo. The semi solid mass obtained was washed with diisopropyl ether. The title compound was isolated as light yellow solid. The compound was characterized by spectral analysis. ESI-MS 453 (M+H) + Step 3: Preparation of 3-(3,4-dihydro-2H-quinolin-1-v1)-2-{4-[2-(2,5-dimethyl-phenoxy)-ethoxy]-benzyl}-3-oxo-propionitrile [0199] 2-(3,4-Dihydro-2H-quinoline-1-carbonyl)-3-{4-[2-(2,5-dimethyl-phenoxy)-ethoxy]-phenyl}-acrylonitrile [1 eq] obtained from step 2 was dissolved in 10:1 (v/v) THF:water. Sodium borohydride [6 eq] was added at 0° C. The reaction mixture was stirred at 0° C. for 2-4 hr. Reaction mixture was quenched in water. The aqueous layer was extracted with EtOAc. The organic layer was washed with brine, dried over sodium sulfate and concentrated in vacuo to afford colorless oily compound. The title compound was characterized by spectral analysis. ESI-MS 455 (M+H) + Step 4: 2-Aminomethyl-1-(3,4-dihydro-2H-quinolin-1-yl)-3-{4-[2-(2,5-dimethylphenoxy)-ethoxy]-phenyl}-propan-1-one [0200] This compound was prepared using the general process described in Method-A above. To a solution of 3-(3,4-dihydro-2H-quinolin-1-yl)-2-{4-[2-(2,5-dimethyl-phenoxy)-ethoxy]-benzyl}-3-oxo-propionitrile [1 eq] obtained from step 3 and cobalt(II) chloride hexahydrate [2 eq] in methanol, sodium borohydride [1 eq] was added at 0° C. in parts. The mixture was stirred for 3 hr at 0° C. The mixture was quenched in water; aqueous layer was extracted with dichloromethane. Organic layer was washed with brine, dried over sodium sulfate and concentrated in vacuo to afford thick liquid. Purification of crude product was thus obtained by the way of column chromatography (Aluminium oxide Basic 0.1:10 (v/v)::chloroform:methanol). The title compound was isolated as thick liquid and was characterized by spectral analysis. ESI-MS 459(M+H) + HPLC t Ret ; 17.07 min. [0201] The following compounds (Example 2-24) were prepared by following the general process described in Method-A above, at appropriate places as in Example 1. Example 2 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-(3,4-dihydro-2H-quinolin-1-yl)-propan-1-one [0202] Prepared similar to the procedure described in Example 1 but using instead Aldehyde 2 and 1,2,3,4-tetrahydro quinoline as starting material. The title compound was obtained as thick liquid ESI-MS: M + =513.1; HPLC t Ret ; 17.27 min. Example 3 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-(3,4-dihydro-1H-isoquinolin-2-yl)-propan-1-one [0203] Prepared similar to the procedure described in Example 1 but using instead Aldehyde 2 and 1,2,3,4-tetrahydroisoquinoline. The title compound was obtained as thick liquid ESI-MS: M + : 513.0; HPLC t Ret ; 17.06 min. Example 4 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-(2,3-dihydro-benzo[1,4]oxazin-4-yl)-propan-1-one [0204] Prepared similar to the procedure described in Example 1 but using instead Aldehyde 2 and 3,4-Dihydro-2H-benzo[1,4]oxazine. The title compound was obtained as thick liquid ESI-MS: m + : 515.0; HPLC t Ret ; 17.06 min. Example 5 3-Amino-1-(6-chloro-3,4-dihydro-2H-quinolin-1-yl)-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-propan-1-one [0205] Prepared similar to the procedure described in Example 1 but using instead Aldehyde 2 and Amine 2. The title compound was obtained as thick liquid ESI-MS: M + : 548.70; HPLC t Ret : 17.91 min. Example 6 3-Amino-1-(6-bromo-3,4-dihydro-2H-quinolin-1-yl)-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-propan-1-one [0206] Prepared similar to the procedure described in Example 1 but using instead Aldehyde 2 and Amine 11. The title compound was obtained as thick liquid ESI-MS: M + : 593.0; HPLC t Ret : 18.01 min. Example 7 3-Amino-1-(7,8-dichloro-3,4-dihydro-2H-quinolin-1-yl)-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-propan-1-one [0207] Prepared similar to the procedure describe in Example 1 but using instead Aldehyde 2 and Amine 3. The title compound was obtained as thick liquid ESI-MS: M + : 582.8; HPLC t Ret : 18.08 min. Example 8 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-(8-methoxy-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one [0208] Prepared similar to the procedure described in Example 1 but using instead Aldehyde 2 and Amine 4. The title compound was obtained as thick liquid ESI-MS: M + : 543.0; HPLC t Ret : 17.46 min Example 9 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-(7,8-dimethyl-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one [0209] Prepared similar to the procedure described in Example 1 but using instead Aldehyde 2 and Amine 5. The title compound was obtained as thick liquid ESI-MS: M + : 541.0; HPLC t Ret : 18.16 min Example 10 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-(6-methyl-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one [0210] Prepared similar to the procedure described in Example 1 but using instead Aldehyde 2 and Amine 6. The title compound was obtained as thick liquid ESI-MS: M + : 527.0; HPLC t Ret : 17.72 min Example 11 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-(8-fluoro-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one [0211] Prepared similar to the procedure described in Example 1 but using instead Aldehyde 2 and Amine 7. The title compound was obtained as thick liquid ESI-MS: M + : 531.0; HPLC t Ret : 17.12 min Example 12 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-piperidin-1-yl-propan-1-one [0212] Prepared similar to the procedure described in Example 1 but using instead Aldehyde 2 and piperidine. The title compound was obtained as thick liquid ESI-MS: M + : 465.1; HPLC t Ret : 16.25 min Example 13 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-(6-methoxy-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one [0213] Prepared similar to the procedure described in Example 1 but using instead Aldehyde 2 and 6-methoxy-1,2,3,4-tetrahydro quinoline. The title compound was obtained as thick liquid ESI-MS: M + : 544; HPLC t Ret : 17.09 min Example 14 3-Amino-1-(6,8-dichloro-3,4-dihydro-2H-quinolin-1-yl)-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-propan-1-one [0214] Prepared similar to the procedure described in Example 1 but using instead Aldehyde 2 and Amine 9. The title compound was obtained as thick liquid ESI-MS: M + : 582.8; HPLC t Ret : 18.35 min. Example 15 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-(6-trifluoro methyl-3,4-dihydro-2H -quinolin-1-yl)-propan-1-one [0215] Prepared similar to the procedure described in Example 1 but using instead Aldehyde 2 and Amine 8 The title compound was obtained as thick liquid ESI-MS: M + : 580.9; HPLC t Ret : 18.34 min. Example 15A 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-(6-trifluoro methyl-3,4-dihydro-2H -quinolin-1-yl)-propan-1-one hydrochloride [0216] Example 15 (1 eq) was dissolved in 4M dioxane.HCl at 10° C. Mixture was stirred for 20 min at same temperature. Organic volatiles were removed under reduced pressure to get title compound as sticky solid. ESI-MS: M + : 581; HPLC t Ret : 18.51 min. Example 15B 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-(6-trifluoro methyl-3,4-dihydro-2H -quinolin-1-yl)-propan-1-one hemifumarate [0217] Example 15 (1 eq) was dissolved in ethanol (5 v) and to this fumaric acid (1 eq) was added and mixture was stirred for 3 h at ambient temperature. Organic volatiles were removed under reduced pressure to afford title compound as white sticky solid. ESI-MS: M + : 581; HPLC t Ret : 18.80 min. Example 16 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-(6-methyl-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one [0218] Prepared similar to the procedure described in Example 1 but using instead Aldehyde 2 and Amine 6. The title compound was obtained as thick liquid ESI-MS: M + : 527.0; HPLC t Ret : 17.19 min. Example 17 2-Aminomethyl-3-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-phenyl}-1-(6,7-dimethoxy-3,4-dihydro-1H-isoquinolin-2-yl)-propan-1-one [0219] Prepared similar to the procedure described in Example 1 but using instead Aldehyde 2 and 6,7-dimethoxy-1,2,3,4-tetrahydro isoquinoline. The title compound was obtained as thick liquid ESI-MS: M + : 574.7; HPLC t Ret : 16.24 min. Example 18 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-(4-methyl-piperidin-1-yl)-propan-1-one [0220] Prepared similar to the procedure described in Example 1 but using instead Aldehyde 2 and 4-methyl piperidine. The title compound was obtained as thick liquid ESI-MS: M + : 479; HPLC t Ret : 16.85 min. Example 19 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-(4-pyrimidin-2-yl-piperazin-1-yl)-propan-1-one [0221] Prepared similar to the procedure described in Example 1 but using instead Aldehyde 2 and 2-piperazin-1-yl-pyrimidine. The title compound was obtained as thick liquid ESI-MS: M + : 544; HPLC t Ret : 15.50 min. Example 20 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-(6-fluoro-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one [0222] Prepared similar to the procedure described in Example 1 but using instead Aldehyde 2 and Amine 1. The title compound was obtained as thick liquid ESI-MS: M + : 532.6; HPLC t Ret : 17.45 min. Example 21 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-[4-(2-methoxy-ethoxy)-piperidin-1-yl]-propan-1-one [0223] Prepared similar to the procedure described in Example 1 but using instead Aldehyde 2 and Amine 16. The title compound was obtained as thick liquid ESI-MS: M + : 539.1; HPLC t Ret : 15.75 min. Example 22 2-Aminomethyl-3-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-phenyl}-1-(4-methyl-piperazin-1-yl)-propan-1-one [0224] Prepared similar to the procedure described in Example 1 but using instead Aldehyde 2 and N-methyl piperazine. The title compound was obtained as thick liquid ESI-MS: M + : 480; HPLC t Ret : 13.10 min. Example 23 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-pyrrolidin-1-yl-propan-1-one [0225] Prepared similar to the procedure described in Example 1 but using instead Aldehyde 2 and pyrrolidine. The title compound was obtained as thick liquid ESI-MS: M + : 450.9; HPLC t Ret : 15.80 min. Example 24 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-[6-(3-methoxy-propoxy)-3,4-dihydro-2H-quinolin-1-yl]-propan-1-one [0226] Prepared similar to the procedure described in Example 1 but using instead Aldehyde 2 and Amine 13. The title compound was obtained as thick liquid ESI-MS: M + : 601; HPLC t Ret : 17.87 min. Example 25 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-morpholin-4-yl-propan-1-one hydrochloride Step 1: 2-{4-[2-(2,6-Dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-3-morpholin-4-yl-3-oxo-propionitrile [0227] Prepared similar to the procedure described in Example 1 but using Aldehyde 2 and morpholine. instead Step 2: (2-{4-[2-(2,6-Dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-3-morpholin-4-yl-3-oxo-propyl)-carbamic acid tert-butyl ester [0228] The compound was prepared following the general process described in Method-B above. [0229] 2-{4-[2-(2,6-Dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-3-morpholin-4-yl-3-oxo-propionitrile (1 eq) obtained from step 1 was dissolved in methanol (15 mL) and to this, added Raney Ni, Boc anhydride (1.2 eq) and triethyl amine (1.5 eq). Reaction mixture was hydrogenate using Parr Apparatus under H 2 atmosphere at 60 psi for 6 hr. Mixture was filtered through hyflow. Hyflow bed was washed with methanol. Organic solvent was evaporated in vacuo to afford title compound as liquid. The crude product was purified by the way of column chromatography (SiO 2 , 6:4 (v/v) Hexane:EtOAc) to afford title compound as thick liquid. Step 3: 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-morpholin-4-yl-propan-1-one hydrochloride [0230] Dioxane.HCl (10%, 2v) was added to (2-{4-[2-(2,6-Dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-3-morpholin-4-yl-3-oxo-propyl)-carbamic acid tent-butyl ester (1 eq) at 0-5° C. and mixture was stirred for 1 hr at same temperature. Organic volatiles were removed under reduced pressure to afford title compound hydroscopic solid. ESI-MS: M + : 466.61; HPLC t Ret : 15.31 min. [0231] The following compounds (Example 26-48) were prepared by following the general process described in Method-B above, at appropriate places as in Example 25. Example 26 2-Aminomethyl-3-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-phenyl}-1-(3-methoxymethyl-piperidin-1-yl)-propan-1-one hydrochloride [0232] Prepared similar to the procedure described in Example 25 but using instead Aldehyde 2 and Amine 14. The title compound was obtained as hygroscopic solid ESI-MS: M + : 508.6; HPLC t Ret : 16.60 min. Example 27 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-(6-trifluoromethoxy-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one hydrochloride [0233] Prepared similar to the procedure described in Example 25 but using instead Aldehyde 2 and Amine 10. The title compound was obtained as hygroscopic solid ESI-MS: M + : 596.7; HPLC t Ret : 18.75 min. Example 28 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-[6-(2,2,2-trifluoro-ethoxy)-3,4-dihydro-2H-quinolin-1-yl]-propan-1-one hydrochloride [0234] Prepared similar to the procedure described in Example 25 but using Aldehyde 2 and Amine 12 instead. The title compound was obtained as hygroscopic solid ESI-MS: M + : 611; HPLC t Ret : 18.56 min. Example 29 D-(2-Aminomethyl-3-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-phenyl}-propionyl)-pyrrolidine-2-carboxylic acid methyl ester hydrochloride [0235] Prepared similar to the procedure described in Example 25 but using Aldehyde 2 and D-proline methyl ester instead. The title compound was obtained as mixture of diastereomers and nature was hygroscopic solid ESI-MS: m + : 509; HPLC t Ret : 16.32 & 16.47 min. Example 30 2-Aminomethyl-3-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-phenyl}-1-(3-methoxy-piperidin-1-yl)-propan-1-one hydrochloride [0236] Prepared similar to the procedure described in Example 25 but using Aldehyde 2 and Amine 15 instead. The title compound was obtained as hygroscopic solid ESI-MS: 495.7; HPLC t Ret : 16.22 min. Example 31 3-Amino-2-{4-[2-(2,6-dichloro-phenoxy)-ethoxy]-benzyl}-1-(6-trifluoromethyl-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one hydrochloride [0237] Prepared similar to the procedure described in Example 25 but using Aldehyde 3 and Amine 8 instead. The title compound was obtained as hygroscopic solid ESI-MS: M + : 567; HPLC t Ret : 17.77 min. Example 31A [0238] 3-Amino-2-{4-[2-(2,6-dichloro-phenoxy)-ethoxy]-benzyl}-1-(6-trifluoromethyl-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one hydrochloride synthesized as per the procedure reported in Example 31 was subjected to purification by HPLC using a chiral stationary phase Regis (R, R) Whelk-01 column, 10/100 FEC [250*4.6 mm], 5 u, 1.5 ml/min, mobile phase (90:10) N-hexane:0.1% TEA in Ethanol over 40 min yielded non-polar isomer ESI-MS: M + 566.93, HPLC Chiral Regis Whelk column t Ret 32.32 min. Example 31B [0239] 3-Amino-2-{4-[2-(2,6-dichloro-phenoxy)-ethoxy]-benzyl}-1-(6-trifluoromethyl-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one hydrochloride synthesized as per the procedure reported in Example 31 was subjected to purification by HPLC using a chiral stationary phase Regis (R, R) Whelk-01 column, 10/100 FEC [250*4.6 mm], 5 u, 1.5 ml/min, mobile phase (90:10) N-hexane:0.1% TEA in Ethanol over 40 min yielded polar isomer ESI-MS: 566.90, HPLC Chiral Regis Whelk column t Ret 20.40 min. Example 32 3-Amino-2-{4-[2-(2,6-dichloro-phenoxy)-ethoxy]-benzyl}-1-(6-trifluoromethoxy-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one hydrochloride [0240] Prepared similar to the procedure described in Example 25 but using Aldehyde 3 and Amine 10 instead. The title compound was obtained as hygroscopic solid ESI-MS: M + : 582.6; HPLC t Ret : 18.12 min. Example 33 3-Amino-2-{4-[2-(2-chloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-(6-trifluoromethyl-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one [0241] Prepared similar to the procedure described in Example 25 but using Aldehyde 12 and Amine 8 instead. The title compound was obtained as hygroscopic solid ESI-MS: M + : 547; HPLC t Ret : 17.97 min. Example 34 3-Amino-2-{4-[2-(2,6-difluoro-phenoxy)-ethoxy]-benzyl}-1-(6-trifluoromethyl-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one hydrochloride [0242] Prepared similar to the procedure described in Example 25 but using Aldehyde 4 and Amine 8 instead. The title compound was obtained as hygroscopic solid ESI-MS: M + : 534.6; HPLC t Ret : 17.05 min. Example 35 3-Amino-2-{4-[2-(2,6-difluoro-phenoxy)-ethoxy]-benzyl}-1-(6-fluoro-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one hydrochloride [0243] Prepared similar to the procedure described in Example 25 but using Aldehyde 4 and Amine 1 instead. The title compound was obtained as hygroscopic solid ESI-MS: 484.7; HPLC t Ret : 16.09 min. Example 36 3-Amino-2-{4-[2-(2,4-difluoro-phenoxy)-ethoxy]-benzyl}-1-(6-trifluoromethyl-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one hydrochloride [0244] Prepared similar to the procedure described in Example 25 but using Aldehyde 5 and Amine 8 instead. The title compound was obtained as hygroscopic solid ESI-MS: M + : 534.7; HPLC t Ret : 17.08 min. Example 37 3-Amino-2-{4-[2-(2,4-dichloro-phenoxy)-ethoxy]-benzyl}-1-(6-fluoro-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one hydrochloride [0245] Prepared similar to the procedure described in Example 25 but using Aldehyde 6 and Amine 1 instead. The title compound was obtained as hygroscopic solid ESI-MS: M + : 517; HPLC t Ret : 17.42 min. Example 38 3-Amino-2-{4-[2-(2,4-dichloro-phenoxy)-ethoxy]-benzyl}-1-(6-trifluoromethyl-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one hydrochloride chloride [0246] Prepared similar to the procedure described in Example 25 but using Aldehyde 6 and Amine 8 instead. The title compound was obtained as hygroscopic solid ESI-MS: M + : 567; HPLC t Ret : 18.37 min. Example 39 3-Amino-2-{4-[2-(4-chloro-2-fluoro-phenoxy)-ethoxy]-benzyl}-1-(6-fluoro-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one hydrochloride [0247] Prepared similar to the procedure described in Example 25 but using Aldehyde 7 and Amine 1 instead. The title compound was obtained as hygroscopic solid ESI-MS: M + : 501; HPLC t Ret : 16.48 min. Example 40 3-Amino-2-{4-[2-(4-chloro-2-fluoro-phenoxy)-ethoxy]-benzyl}-1-(6-trifluoromethyl-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one hydrochloride [0248] Prepared similar to the procedure described in Example 25 but using Aldehyde 7 and Amine 8 instead. The title compound was obtained as hygroscopic solid ESI-MS: M + : 551.3; HPLC t Ret : 18.74 min. Example 41 3-Amino-2-{6-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-pyridin-3-ylmethyl}-1-(6-trifluoromethyl-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one [0249] Prepared similar to the procedure described in Example 1 but using Aldehyde 8 and Amine 8 instead. The title compound was obtained as thick liquid ESI-MS: M + : 582; HPLC t Ret : 17.84 min Example 42 2-Aminomethyl-3-{6-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-pyridin-3-yl}-1-piperidin-1-yl-propan-1-one [0250] Prepared similar to the procedure described in Example 1 but using Aldehyde 8 and piperidine instead. The title compound was obtained as thick liquid ESI-MS: M + : 466; HPLC t Ret : 15.53 min. Example 43 2-Aminomethyl-3-{6-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-pyridin-3-yl}-1-(3,4-dihydro-2H-quinolin-1-yl)-propan-1-one [0251] Prepared similar to the procedure described in Example 1 but using Aldehyde 8 and 1,2,3,4-tetrahydro quinoline instead. The title compound was obtained as thick liquid ESI-MS: M + : 514; HPLC t Ret : 16.69 min. Example 44 3-Amino-2-{6-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-pyridin-3-ylmethyl}-1-(6-fluoro-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one hydrochloride [0252] Prepared similar to the procedure described in Example 25 but using Aldehyde 8 and Amine 1 instead. The title compound was obtained as hygroscopic solid ESI-MS: M + : 533.3 ; HPLC t Ret : 16.79 min. Example 45 2-Aminomethyl-3-{4-[3-(2,6-dichloro-4-methyl-phenoxy)-propoxy]-phenyl}-1-(3,4-dihydro-2H-quinolin-1-yl)-propan-1-one [0253] Prepared similar to the procedure described in Example 1 but using Aldehyde 9 and 1,2,3,4-tetrahydro quinoline instead. The title compound was obtained as thick liquid ESI-MS: M + : 527; HPLC t Ret : 18.10 min. Example 46 3-Amino-1-(6-fluoro-3,4-dihydro-2H-quinolin-1-yl)-2-{4-[3-(2-methoxy-benzyloxy)-propoxy]-benzyl}-propan-1-one [0254] Prepared similar to the procedure described in Example 1 but using Aldehyde 10 and Amine 1 instead. The title compound was obtained as thick liquid ESI-MS: M + : 507 ; HPLC t Ret : 16.55 min. Example 47 3-Amino-2-{4-[3-(2-methoxy-benzyloxy)-propoxy]-benzyl}-1-(6-trifluoromethyl-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one [0255] Prepared similar to the procedure described in Example 1 but using Aldehyde 10 and Amine 8 instead. The title compound was obtained as thick liquid ESI-MS: M + : 557; HPLC t Ret : 17.54 min. Example 48 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-3-methoxy-benzyl}-1-(3,4-dihydro-2H-quinolin-1-yl)-propan-1-one hydrochloride [0256] Prepared similar to the procedure described in Example 25 but using Aldehyde 11 and 1,2,3,4-tetrahydroquinoline instead. The title compound was obtained as hygroscopic solid ESI-MS: M + : 543; HPLC t Ret : 16.93 min. Example 49 1-(3-(6-Chloro-3,4-dihydro-2H-quinolin-1-yl)-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-3-oxo-propyl)-3-phenyl-urea Step-1: 3-Amino-1-(6-chloro-3,4-dihydro-2H-quinolin-1-yl)-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-propan-1-one [0257] Prepared similar to the procedure described in Example 5. Step-2 [0258] 3-Amino-1-(6-chloro-3,4-dihydro-2H-quinolin-1-yl)-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-propan-1-one (1eq), phenyl isocyanate (1eq) and triethyl amine 1.2 eq) were taken in dichloromethane. Mixture was stirred for 6 h at room temperature. Mixture was quenched in water; product was extracted with EtOAc. Organic layer was washed with brine, dried over sodium sulfate, filtered and evaporated in vacuo to afford brown sticky solid. ESI-MS. (M+23) 690, HPLC t Ret : 25.80 min. Example 50 [2-{4-[2-(2,6-Dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-3-oxo-3-(6-trifluoromethyl-3,4-dihydro-2H -quinolin-1-yl)-propyl]-carbamic acid tent-butyl ester Step 1: 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-(6-trifluoro methyl-3,4-dihydro-2H -quinolin-1-yl)-propan-1-one was prepared similar to the procedure described in Example 15 Step 2 [0259] 3-Amino-2-{4-[2-(2,6-dichloro-4-methyl-phenoxy)-ethoxy]-benzyl}-1-(6-trifluoromethyl-3,4-dihydro-2H -quinolin-1-yl)-propan-1-one (1 eq) obtained from step 1, Boc anhydride (1.1eq), triethylamine (1.3 eq) were mixed in DCM (5 v) and stirred for 3 h at 25° C. Mixture was diluted with water. Product was extracted with EtOAc. Organic layer was washed with brine, dried over sodium sulfate, filtered, and evaporated in vacuo to afford thick liquid. ESI-MS. (M+23) 704.7 HPLC t Ret : 27.09 min. Example 51 3-Amino-2-{4-[2-(2,6-dichloro-phenyl)-ethoxy]-benzyl}-1-(6-trifluoromethyl-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one hydrochloride [0260] Prepared similar to the procedure described in Example 25 but using Aldehyde 13 and Amine 8 instead. The title compound was obtained as hygroscopic solid ESI-MS: M + : 551.4; HPLC t Ret : 13.44 min. Example 52 3-Amino-2-{4-[2-(2,6-dichloro-phenyl)-ethoxy]-benzyl}-1-(6-fluoro-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one hydrochloride [0261] Prepared similar to the procedure described in Example 25 but using Aldehyde 13 and Amine 1 instead. The title compound was obtained as hygroscopic solid ESI-MS: M + : 500.7; HPLC t Ret : 11.99 min. Example 53 3-Amino-1-(6-tert-butyl-3,4-dihydro-2H-quinolin-1-yl)-2-{4-[2-(2,6-dichloro-phenoxy)-ethoxy]-benzyl}-propan-1-one hydrochloride [0262] Prepared similar to the procedure described in Example 25 but using Aldehyde 3 and Amine 17 instead. The title compound was obtained as hygroscopic solid ESI-MS: (M+H) + : 556.82; HPLC t Ret : 18.86 min. Example 54 3-Amino-2-{4-[2-(piperidin-4-yloxy)-ethoxy]-benzyl}-1-(6-trifluoromethyl-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one hydrochloride [0263] Prepared similar to the procedure described in Example 25 but using Aldehyde 14 and Amine 8 instead. The title compound was obtained as hygroscopic solid ESI-MS: (M) + : 505.6; HPLC t Ret : 12.03 min. Example 55 3-Amino-1-(3-amino-pyrrolidin-1-yl)-2-{4-[2-(2,6-dichloro-phenoxy)-ethoxy]-benzyl}-propan-1-one [0264] Prepared similar to the procedure described in Example 1 but using Aldehyde 3 and 3-amino-pyrrolidine-1-carboxylic acid tert-butyl ester, instead. The title compound was obtained as hygroscopic solid ESI-MS: (M) + : 551.7; HPLC t Ret : 16.098 min. Example 56 2-Aminomethyl-3-{4-[2-(2,6-dichloro-phenoxy)-ethoxy]-phenyl}-1-(2,3-dihydro-indol-1-yl)-propan-1-one hydrochloride [0265] Prepared similar to the procedure described in Example 25 but using Aldehyde 3 and 2,3-dihydro-1H-indole, instead. The title compound was obtained as hygroscopic solid ESI-MS: (M+H) + : 487.7 HPLC t Ret : 16.75 min. Example 57 3-Amino-2-{4-[2-(2,4-difluoro-phenoxy)-ethoxy]-benzyl}-1-(6-trifluoromethoxy-3,4-dihydro-2H-quinolin-1-yl)-propan-1-one hydrochloride [0266] Prepared similar to the procedure described in Example 25 but using Aldehyde 5 and Amine 12, instead. The title compound was obtained as hygroscopic solid ESI-MS: (M+H) + : 550.7; HPLC t Ret : 17.273 min. Example 58 3-Amino-2-{4-[2-(2,4-difluoro-phenoxy)-ethoxy]-benzyl}-1-piperidin-1-yl-propan-1-one hydrochloride [0267] Prepared similar to the procedure described in Example 25 but using Aldehyde 5 and piperidine instead. The title compound was obtained as hygroscopic solid ESI-MS: (M) + : 418.90; HPLC t Ret : 15.036 min. Example 59 3-Amino-2-{4-[2-(2,4-difluoro-phenoxy)-ethoxy]-benzyl}-1-(3,4-dihydro-2H-quinolin-1-yl)-propan-1-one hydrochloride [0268] Prepared similar to the procedure described in Example 25 but using Aldehyde 5 and 1,2,3,4-tetrahydroquinoline, instead. The title compound was obtained as hygroscopic solid ESI-MS: (M) + : 467; HPLC t Ret : 16.011 min. [0269] Biological Data: [0270] In-Vitro Renin Inhibition Assay [0271] The enzymatic in vitro assay was performed in 96 well polypropylene plate (Nunc), using a modified Renin inhibitor screening assay protocol (Cayman, cat no: 10006270). The reaction system comprised assay buffer containing 50 mM Tris-HCL, pH=8.0 & 100 mM sodium chloride, human recombinant renin (1:20 diluted with fixed activity), synthetic renin substrates (9.5 μM) and different concentrations of renin inhibitors in DMSO in a total reaction system of 100 μl. The entire incubation mixture were incubated at 37° C. for 30 mins and the fluorescence was read in kinetic mode using excitation wavelengths of 335-345 nm and emission wavelengths of 485-510 nm. Enzyme inhibition was determined by percent inhibition of renin activity. [0272] The following table shows the Renin inhibition of selected compounds at 1μM and 0.1 μM concentration. [0000] Compounds 1 μM 0.1 μM Example 2 97.3 90.5 Example 4 73.5 — Example 5 79.62 — Example 6 86.48 — Example 9 98.13 80.49 Example 11 68.53 — Example 12 90.71 77.0 Example 13 96.53 32.1 Example 14 86.96 41.79 Example 15 98.66 99.19 Example 15A 88.0 80.00 Example 16 87.41 52.65 Example 17 53.57 — Example 18 65.83 — Example 20 96.11 67.96 Example 23 81.10 59.53 Example 24 93.19 90.71 Example 25 76.40 45.08 Example 26 93.93 92.80 Example 27 99.18 100.0 Example 28 — 73.76 Example 29 — 90.3 Example 30 92.93 92.80 Example 31 102.36 94.13 Example 32 — 100.0 Example 33 89.22 92.88 Example 34 — 31.23 Example 35 — 26.27 Example 36 — 45.04 Example 37 — 36.38 Example 38 — 35.41 Example 39 — 36.30 Example 40 — 38.93 Example 41 98.60 80.10 Example 42 82.45 71.05 Example 43 64.24 — Example 44 96.27 63.10 Example 45 97.06 18.7 Example 47 — 43.08 Example 48 58.47 — Example 53 — 93.08 [0273] Following table represents measured IC 50 values of the selected compounds for its Renin inhibition in human plasma. [0000] Compounds IC 50 nM Example 12 70.15 Example 15A 7.85 Example 26 27.75 Example 27 0.921 Example 31 28.69 Example 32 0.829 Example 24 25.41 [0274] The compounds of the present invention were found to be inhibitors of renin and found to be safe and non-toxic.

The present invention relates to renin inhibitors of formula (I), their pharmaceutically acceptable salts and pharmaceutical compositions containing them. The present invention also relates to a process of preparing compounds of general formula (I), their tautomeric forms, their pharmaceutically acceptable salts, pharmaceutical compositions containing them, and novel intermediates involved in their synthesis.

BACKGROUND OF THE INVENTION [0001] The present invention relates to the field of turbomachines and relates more particularly to multibody gas turbine engines. It relates to engine assembly operations and in particular to the fitting of the low pressure turbine module to a high pressure body. DESCRIPTION OF THE PRIOR ART [0002] A turbojet with a front turbofan and a double body, for example, comprises a low pressure (LP) body and a high pressure (HP) body. The LP body rotates at a first speed and the LP turbine drives the fan. The HP body rotates at a speed different from that of the LP turbine. The shafts of the two bodies are concentric, the low pressure shaft is guided in rotation in bearings supported by the fixed structure of the engine, respectively situated downstream of the turbine and upstream of the high pressure compressor. The shaft of the high pressure body is guided in rotation by bearings supported by the fixed structure of the engine upstream and by the shaft of the low pressure body by means of downstream inter-shaft bearings. The latter are of the roller bearing type and situated, at least according to a known engine, between the high pressure turbine and the low pressure turbine. The bearing comprises an inner ring equipped with rollers held by a cage on the LP shaft and an outer ring shrink fitted in the HP shaft. The fitting of this bearing, that is to say the assembly of the outer ring with the assembly formed by the rollers, of the cage and of the inner ring, is carried out at the same time as the mating of the low pressure turbine where the shaft, previously fitted to the low pressure turbine, is guided into the high pressure body. The term “mating” here refers to all or part of the translational movement of the LP turbine module until the flange of the outer casing of the latter comes into contact with the corresponding flange of the HP module. [0003] It follows that the assembly of the inter-shaft bearing is carried out blind. The operator has no visibility for monitoring, in particular, the engagement of the rollers in the HP rotor and then in the outer ring. This operation comprises high risks of damage to the bearing if the conditions are not controlled. The highest risk for the bearing is a hard contact between the rollers and the retaining nut of the outer ring and the ring itself. [0004] At present, the means used do not make it possible to fit the LP turbine without risk to this inter-shaft bearing, because of the heating method used and of the imprecise positioning of the LP turbine. In particular, the heating of the HP part (equipped with the outer ring) is carried out from the inside of the journal by means of a diffuser fed by a heater. The temperature measurement is carried out manually using a probe applied against the outside of the HP part. The investigations carried out on this operating method have revealed several disadvantages: a relatively high heterogeneity, of the order of 20° C., of the temperature levels of the heated parts, a high risk of adding pollution by the ambient air taken for the heating and the heating device itself, and a high risk of damage of the outer ring of the bearing by contact with the diffuser. This risk is particularly high as the clearance between the diffuser and the outer ring is only a few millimeters, and the assembly is installed on rollers and therefore presenting a risk of being moved inadvertently by the operators. SUMMARY OF THE INVENTION [0008] The objective of the invention is to improve the assembly conditions of LP turbines on an engine of the type described above in order to reduce the risks of damaging the inter-shaft bearing. [0009] More generally, the invention relates to the assembly of a turbomachine, in particular of a gas turbine engine, comprising at least a first module and a second module with a bearing comprising an outer ring shrink-fitted inside a journal integral with the first module and an inner ring integral with the second shaft, according to which the second module is assembled on the first module by engagement of the second shaft, with said inner ring, inside the journal comprising said outer ring. [0010] According to the invention the desired objectives are achieved with an assembly method wherein it comprises the following steps: mating the second module with the second shaft inside the first module up to a determined distance from the journal, centering the second shaft with respect to the journal, said centering being controlled on the basis of measuring distance deviations with respect to a reference on the journal, expansion of the outer ring by heating the external surface of the journal, completion of the mating of the second module. [0015] In the particular case described above, the first module is the HP body and the second module is the low pressure turbine LP, the journal being in the extension of the shaft, the first shaft, and integral with it, of the HP body and the second shaft being the LP turbine shaft. [0016] However, the journal can also be a hollow part, fixed or mobile in rotation, which forms the support of the outer ring of the bearing. [0017] By controlling the centering of the shaft with respect to the journal, correct positioning is guaranteed, which allows, once the journal is expanded, trouble-free mating. Moreover, the heating of the journal from the outside frees space allowing the engagement of the shaft and consequently reduces the assembly time. [0018] According to another feature of the method, in a step prior to the mating of the second module, the journal is heated for the fitting of the outer ring in the HP journal. [0019] The inner ring is preferably equipped with the rolling element of the bearing. In particular, the rolling element consists of rollers held together in a cage. [0020] Preferably, an annular heating means is put into position on the journal between the mating step and the expansion of the journal by heating. During this step, the temperature of the journal or of the ring is measured and the heating is controlled until a determined temperature is reached. [0021] According to another feature of the method, the mating of the second module is carried out when the measured values of the temperatures and of the distance deviations with respect to the journal are within predetermined limits, assuring a trouble-free assembly. [0022] The invention also relates to the device for the implementation of the method, comprising a mobile frame supporting an annular journal-heating means, at least one temperature probe arranged to measure the temperature of the journal, and a means of measuring the radial distance deviation between a shaft to be fitted in the journal and a reference on the journal. [0023] Preferably, the support of the heating means on the frame is arranged to allow the positioning of the heating means around the journal on the one hand and in a retracted position on the other hand. More particularly, the frame comprises a means forming a stop to immobilize the frame with respect to the fixed module of the engine. [0024] According to another feature of the method, the annular heating means comprises a hot gas annular diffuser fed by at least two heaters. Advantageously, the temperature measuring probe is integral with the heating means. The means of measuring radial distance deviations between the reference and the shaft is integral with the frame, and with the heating means in particular. [0025] The device can also comprise a control means receiving the temperature measurement signal and the distance measurement signal, and indicating the thermal and geometric corrections whilst providing the information indicating if the mating can be completed in accordance with the imposed quality criteria. BRIEF DESCRIPTION OF THE DRAWINGS [0026] Other features and advantages will emerge on reading the following description of a non-limiting embodiment of the invention, applied to the fitting of a low pressure turbine module in the high pressure body of a double-body gas turbine, given with reference to the appended drawings in which: [0027] FIG. 1 shows an engine in the process of assembly; [0028] FIG. 2 shows a detail of the inter-shaft bearing before assembly; [0029] FIG. 3 shows the same zone as FIG. 2 , after assembly; [0030] FIGS. 4 to 6 show an equipment supporting a heating device, in the position of use and in a retracted position respectively; [0031] FIG. 7 shows a detail of the heating device in the position of use; [0032] FIG. 8 is an axial cross-sectional view of the device shown in FIG. 7 in position; [0033] FIG. 9 illustrates a detail of the device showing a temperature sensor. DESCRIPTION OF THE PREFERRED EMBODIMENTS [0034] FIG. 1 shows an engine in the process of assembly in which only the outer casings are seen. In this case it is a double-body bypass turbojet such as the CFM56. It comprises a front fan 3 and a module 5 , called the first module, constituted by the HP body with its shaft, called the first shaft. These components are already assembled. In this view the LP turbine module 7 , called the second module, whose shaft 9 , called the second shaft, is already engaged in the HP body, is in the process of being fitted. The critical zone is situated in zone 8 of the inter-shaft bearing whose visibility is zero. [0035] In the continuation of the description, the fitting of this second module, the low pressure module, into the first module, the high pressure module, is therefore described. [0036] In FIG. 2 , this zone is seen in cross-section and in greater detail. The shaft 101 , the second shaft of the second module, the LP turbine, is housed in the shaft 103 , the first shaft, of the first module, the HP body. The shaft 101 comprises at its end, on the right of the figure, a journal 104 for the fitting of a bearing. A radial flange 105 allows the fitting of the various components constituting the LP turbine 110 , which is partly visible. [0037] The shaft 103 of the HP body is extended by a journal 111 at its downstream end. Only a part of the turbine 112 of the HP body can be seen. [0038] The inner-shaft bearing 120 , known per se, comprises an inner ring 121 , fixed to the shaft 101 with the rolling elements, such as rollers 122 , whose cage 122 ′ is crimped on the ring 121 . The outer ring 123 is shrink fitted inside the journal 111 . It is locked in position by a nut 125 . FIG. 3 shows the same components after assembly. The assembly is carried out by translational displacement of the LP turbine module 110 with the shaft 101 towards the left with respect to FIG. 2 , after expansion of the journal together with the outer ring, by heating, the HP module being fixed. It is understood that because of low tolerances, there is a great risk of contact between the rolling parts. This contact can be the cause of scratches, grooves or spalling initiators which are able to result in the fracture of the bearing. [0039] The applicant company has developed a piece of equipment allowing a secure fitting of the LP module in this environment. [0040] The equipment 200 comprises a mobile frame 210 , from which is suspended a means of heating the HP body journal. This assembly is shown in FIGS. 4, 5 and 6 in several positions. [0041] The frame 210 comprises a carriage 211 , mounted on rollers, with a vertical frame member 212 . A support beam 220 is mounted on this frame member provided with rails in order to be able to slide between a first low, active or operating, position, shown in FIG. 4 , and a second high, retracted position, which is seen in FIG. 6 . [0042] A support 230 in the form of an inverted T is fixed to the end of the horizontal arm 222 of the support beam 220 . [0043] The support 230 comprises a vertical arm 232 rigidly fixed with respect to the horizontal arm 222 of the support beam, and two horizontal branches 233 and 234 . The latter are arranged to support two sliders 233 C and 234 C each supporting one half of the annular heating device 300 , 300 A and 300 B respectively, as seen in FIG. 7 . [0044] The equipment is shown in the active position in FIG. 4 . The support 230 is bearing against the flange 51 of the casing of the HP body module. Starting from this position, the heating device is released by separating the two halves 300 A and 300 B which move in direction parallel with the two branches 233 and 234 with their respective slider 233 C and 234 C. Once the heating device is open, it is distanced in the upward direction by commanding the sliding of the support beam 220 in the rails of the frame member 212 . The equipment is shown in the high retracted position in FIG. 6 . [0045] The putting of the heating device into position is carried out using the reverse sequence. [0046] The heating device is described in more detail with reference to FIGS. 7, 8 and 9 . FIG. 7 , which is an enlarged view of FIG. 4 , shows the heating device with three heaters 310 , 312 and 314 , in dotted line, disposed substantially tangentially with respect to an annular enclosure 316 forming a diffuser and air distributor. They are equidistant from each other and deliver a gas heated to a controlled temperature, air in particular, along at least one tangential component. In FIG. 9 it can be seen that the heaters, because of the bulk of the suspension cannot be disposed strictly tangentially with respect to the annular chamber 316 . The latter is delimited by a cylindrical casing 317 and two walls 318 and 319 , perpendicular to the axis of the engine. An inner cylindrical wall 320 is perforated and forms a space with the journal 111 . The casing comprises a thermally insulating material as can be seen on the walls 317 and 318 . [0047] Deflectors 321 are disposed inside the annular enclosure between two consecutive heaters. These deflectors are arched and inclined towards the axis of the engine. The end receiving the gaseous flow from an adjacent heater is at a greater distance from the axis than is the other end. In this way the gas flows emerging into the enclosure are simultaneously driven in a rotational movement about the axis of the engine with a centripetal component towards the perforated wall 320 . [0048] The wall 318 towards the end of the journal comes into contact with the latter. The wall 319 on the other side forms a space or openings for the passage of the gasses which will heat up the thicker mass at that place of the journal. The components of the jacket 317 , 318 , 319 defining the annular enclosure 316 are made of two parts attached to their respective supports 320 A and B. These supports are themselves each suspended from a slider 233 C and 234 C respectively. [0049] The support 230 bears against the flange 51 by stops, one of which is visible in FIG. 8 . It is the stop 232 B integral with the vertical arm 232 of the support. The arm 233 and 234 also comprise chocking means 234 B and 233 B which can be seen in FIG. 7 . The chocks are retractable and become positioned behind the flange 51 in order to ensure the immobilization of the support on the flange 51 . [0050] The device serves as a support for three thermocouples 340 distributed equidistant from each other. FIG. 9 is a partial cross-sectional view of the heating device 300 at the level of one of the thermocouples 340 . The latter is bearing against the downstream surface of the journal in order to sense the temperature. A cable 341 connects the sensor to the control unit which, in particular, comprises the function of controlling the heaters according to the temperature to be reached. In this example, it is seen that the thermocouple is attached to the wall 318 by means of a bracket 342 . [0051] The device also supports three instruments 350 for measuring the distance between the journal 111 and the LP shaft inside the latter. They are distributed equidistant from each other, for example at three o'clock, six o'clock and nine o'clock, as seen from the rear of the engine. The alignment of the LP shaft is carried out by comparing the differences in measurements of distances at these three points and by correlatively acting on the transverse positioning of the shaft in the handling system. The distance measuring instruments 350 are of the laser type for example. They have been shown diagrammatically in FIGS. 7 and 8 . They are mounted on support arms 351 fixed on the horizontal arms of the supports 230 . They can move between two positions as seen in FIG. 8 which shows a measuring instrument positioned high with respect to the axis of the engine. When they are in position 350 of the figure, they aim at the journal; by shifting them into the position 350 ′, they aim at the low pressure shaft. It is thus possible to derive from this the clearance between the shaft and the journal. The three together distributed around the journal make it possible to know the relative position of the two axes accurately. The correction is carried out by moving the turbine module in space using the appropriate control means. [0052] A control console is mounted on the frame. It receives the signals from the temperature sensors and the distance measurements. It also comprises means for providing alarm signals, for example of the green light/red light type, to inform the operator of the situation and of the state of preparation of the journal before mating. [0053] The sequence of operations is as follows. [0054] The engine is partially assembled. The fan 3 and the HP body 5 are assembled. The LP module 7 is waiting. [0000] a) For fitting the outer ring 123 in the journal, [0000] the device is put into position as shown in FIG. 7 , and the journal 111 is heated up to the temperature specified for the fitting; the obtaining of this temperature authorizes the putting into the retracted position, as shown in FIG. 6 , the fitting of the ring 123 , and the tightening of the nut 125 ; b) For the centering of the turbine shaft, the equipment is put into the operating position, the LP shaft 101 is inserted into the HP body, and the distance measuring system 350 is activated. The measurements taken by the instruments 350 allow the centering of the shaft 101 , within the limits specified, with respect to the journal. c) For the heating of the journal/outer ring assembly, the equipment is put into the operating position, and the heating is started. The heating is controlled according to the temperatures measured by the thermocouples 340 until the commanded temperature is reached, to within the specified limits. The obtaining of the temperature within the specified range authorizes the putting of the equipment into the retracted position. [0062] The assembly is completed by proceeding with the final mating. [0063] The device of the invention provides everything with the simultaneous control of the two major assembly conditions in order to ensure risk-free assembly of the bearing. [0064] It is furthermore understood that the invention is not limited to the fitting of the LP turbine in an HP body of a gas turbine engine. It is applicable to all equivalent situations of fitting a second module assembled by a bearing in a first module.

The invention relates to a method of assembly of a turbomachine, in particular of a gas turbine engine, comprising at least a first module and a second module a second shaft assembled by a bearing, said bearing comprising an outer ring shrink-fitted inside a journal integral with the first module and an inner ring integral with the second shaft, according to which the second module is assembled on the first module by engagement of the second shaft, with said inner ring, inside the journal comprising said outer ring, wherein it comprises the following steps: mating the second module with the second shaft up to a determined distance from the journal, centering the second shaft with respect to the journal, said centering being controlled on the basis of measuring distance deviations with respect to a reference on the journal, expansion of the journal by heating its outer surface, completion of the mating of the second shaft.

CROSS REFERENCE TO RELATED APPLICATIONS This application is a continuation of U.S. application Ser. No. 09/259,581, filed Mar. 1, 1995, now abandoned, which is a divisional of U.S. application Ser. No. 08/718,142, filed Sep. 18, 1996, which referred to and claimed priority on U.S. Provisional Application Ser. No. 60/022,110, filed Jul. 17, 1996, which claim of priority is continued. BACKGROUND OF THE INVENTION The present invention relates to a vacuum cup carton handler for a carton loading machine which has a handling section that will bend a flap on a carton to be filled along its score line automatically before depositing the carton onto a conveyor for inserting product. Rotary placers have long been used for handling cartons and carton loading machines. One such device is shown in U.S. Pat. No. 5,456,570. It includes a vacuum holder for receiving cartons from a store or supply, and then moves the carton to a position where it will be deposited on a conveyor for subsequent loading of products into the carton. Vacuum cups are used for holding the carton while the rotary placer moves the carton to the conveyor, and then a control is used for releasing the vacuum so that the carton can be moved along the conveyor. However, U.S. Pat. No. 5,456,570 does not include any structure for positively moving or “breaking” a carton flap between two positions. Carton formation systems of various kinds have been used for erecting cartons so that they can be appropriately packed, and for example U.S. Pat. No. 5,106,359 shows such a provision. The present invention fulfills a need for properly breaking or bending a carton flap along a score line for ease in subsequent handling and loading. SUMMARY OF THE INVENTION The present invention relates to a vacuum gripper used for handling cartons, and which is preferably mounted onto a rotary type placer that will pick a carton at a store station, and will move the carton to a station where it will be released onto a conveyor so that the carton can subsequently be packed. The carton is preferably erected at the time it is deposited on the conveyor, and normally this is done by “breaker bars” or other devices that will engage the carton and cause the carton to be folded from a flat position to an erected position. Cartons have to be closed after they are filled, and normally flaps are provided on at least some of the side panels of the carton along score lines which permit folding the flaps from a flat position to an “open” position where it does not cover the end of the carton. The present handler includes an auxiliary set of vacuum cups that will engage a carton flap, and by actuation of a power actuator, in the form shown, a pneumatic cylinder operated under air pressure, will be moved through a linkage to bend a carton flap substantially 90° about its score line. The flap will then be in an open position when deposited on a conveyor and thereafter can be maintained in such position by guides on the conveyor. The present placer includes the provision of both vacuum and air pressure to the rotary carton handler disclosed, so that the operation of the power actuator can be at any desired annular location in the rotation of the unit. As shown, a vacuum and air pressure slip ring assembly is mounted onto a mounting shaft of the rotary placer on which the carton handling device of the present invention is used, using interfacing surfaces, one stationary and one rotating, that will provide a vacuum and air pressure seal between a stationary member and a rotating member that rotates with the rotary placer. The provision of both vacuum and air pressure to control the handling of the carton provides an efficient way of having actuators mounted on a rotating element for carton manipulation. The manifold forms an important part of the invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of a rotary placer having a carton erecting assembly made according to the present invention installed thereon; FIG. 2 is a side elevational view of the device of FIG. 1 schematically shown with parts in section and parts broken away; FIG. 2A is a fragmentary sectional view of a guide slot for controlling arm movement taken on line 2 A— 2 A in FIG. 2; FIG. 3 is a fragmentary enlarged side elevational view of a vacuum cup linkage mechanism used with the present invention in an actuated position; FIG. 4 is a top plan view of the linkage in FIG. 3 in an initial position; FIG. 4A is a front elevational view of the linkage of FIG. 4; FIG. 5 is a schematic perspective view of the linkage of the present invention in a carton receiving position; FIG. 6 is a schematic perspective view of the device in the present invention in a position where it will deliver a carton with a folded flap to a conveyor; FIG. 7 is a sectional view of a manifold used for transferring both vacuum and air pressure to a rotary placer with parts in section and parts broken away; FIG. 8 is a view taken as on line 8 — 8 in FIG. 7; FIG. 9 is a view taken as on line 9 — 9 in FIG. 7 with parts broken away to show a second portion of the assembly; FIG. 10 is a sectional view taken as on line 10 — 10 in FIG. 7; and FIG. 11 is a sectional view taken as on line 11 — 11 in FIG. 7, which is the same line as the view of FIG. 10 but looking in an opposite direction. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS While the particular type of rotary placer that is utilized is not essential or part of the invention, the rotary placer is partially shown in FIGS. 1 and 2 schematically. Rotary placer 10 is to be used to pick up a carton or other item 11 in a desired position, called a “pick” position from a supply or store 13 having a plurality of cartons and moves the carton to a conveyor that is shown only schematically in FIG. 6 at a place position to place a carton on the conveyor for opening and filling. The rotary placer 10 has a frame 12 mounted on a shaft 14 for rotation about a central axis indicated generally at 15 . A hub 16 and suitable locking members drivably connect the frame 12 to the shaft 14 . Motor and drive 17 rotates the shaft 14 and thus the frame 12 about the central axis 15 . The shaft 14 is mounted on suitable bearings 18 to the machine frame 19 shown only schematically. The pick and place positions are at desired locations to fit the carton loading machine used. As shown, the frame 12 includes three sections for mounting three separate arm assemblies 22 , 23 and 24 , respectively 120° apart. There can be two or more, for example up to eight arms assemblies on the frame. Only one arm assembly is shown completely, but it is to be understood that each of the arm assemblies is constructed identically. The arm assemblies 22 , 23 and 24 are controlled in their motion during rotation of the frame 12 , by a gear set shown generally at 26 , which includes a fixed gear 27 and planet gears 28 that are mounted on suitable shafts which will rotate on bearings relative to the frame 12 . The fixed gear 27 is supported on a hub 30 that is mounted through bearings to the shaft 14 and then held from rotation in a suitable manner, as shown schematically with an arm 32 that is supported relative to the machine frame 19 in a suitable manner. The shaft 14 thus can rotate relative to the gear 27 . The planet gears 28 , as shown, are mounted on suitable shafts 34 and bearing housings 36 mounted on the frame 12 . The planet gears 28 rotate about the central or sun gear 27 when the frame 12 is rotated, and as they do, they also rotate about the axis of the shafts 34 in a known manner. It should be noted that the gear 27 is also mounted on suitable bushings on the shaft 14 , so that the gear can remain stationary as the shaft 14 and the frame 12 rotate. Each of the shafts 34 has a crank arm 38 fixed at an end thereof on an opposite side of the frame 12 from the gears 27 and 28 . Crank arms 38 are used to control movement of a carton pickup assembly indicated generally at 40 , mounted at an outer end of a slider shaft 42 . The slider shaft 42 is reciprocated by the crank arm 38 as the crank arm rotates. A crank pin 44 at the end of the crank arm 38 drives the slider shaft through suitable bearings on the crank pin. The slider shaft 42 is slidably mounted in a hub or housing 46 supported at the outer end of an arm 55 forming one arm of a bell crank assembly 48 . The hub 46 is pivotally mounted on a suitable pin 50 in bearings, at the end of arm 55 of the bell crank assembly 48 . The bell crank assembly 48 in turn is mounted at the inner end of arm 55 on a pivot pin 52 that is secured to the rotating frame 12 . A control arm portion 54 is fixed to an arm 55 . Control arm 54 has a cam follower roller 61 at its outer end (see FIG. 2A) on an opposite side of the arm 54 from that shown in FIG. 2 . The roller rides in a cam track 60 formed in the side of the plate 12 and will move along the cam track 60 to cause the arm 55 and thus hub 46 to move in a desired path as the crank 38 rotates. As the crank arm 38 rotates about the axis of the crank pin 34 , it will cause the slider 42 to move in and out relative to the slider hub 46 . Because of the needed geometry for the operation of the carton pickup assembly 40 , the cam track 60 is provided to permit the arm 52 of the bell crank to move about the axis of the mounting pin 52 , which causes the arm 55 to move and control the position of the carton pickup assembly. The outer end of the slider 42 supports the carton pickup assembly 40 , which includes vacuum cup frame assembly 64 . The vacuum cups are provided with a vacuum through a hose in a conventional manner, as can be seen schematically in FIGS. 5 and 6. Suitable vacuum is provided through a control manifold 68 that transfers both vacuum and air under pressure, as will be explained. The vacuum hoses are just shown schematically at 69 in FIGS. 5 and 6, because they are conventionally used. The vacuum cup frame 64 includes a main cross member 70 that is supported fixedly on a threaded portion and nut at the end of the slider shaft 42 . The cross member 70 thus reciprocates in and out with slider shaft 42 as the crank 38 rotates when above frame 12 is rotating. The position of the cross member 70 is selected to mate with the carton store 13 for holding the cartons 11 at a pick position, to position above a conveyor which is shown schematically in FIG. 6 . The cross member 70 carries a pair of vacuum cups 72 (or more) that are spaced apart a suitable distance and have cup edges that lie on a common plane that is the plane of an exterior surface of a carton 11 . The cross member 70 has a pair of depending brackets 74 fixed thereon as can be seen in FIGS. 2 and 2A. These brackets in turn support a carton flap folding assembly 76 . The carton flap folding assembly 76 includes a pair of pivoting angled brackets 78 that as shown have angularly offset portions. The brackets have mounting shank portions 80 that adjustably mount an auxiliary vacuum cup cross member 82 . The mountings can be adjusted as to length. The cross member 82 in turn mounts suitable vacuum cups 84 . As shown in FIGS. 5 and 6 there can be three such vacuum cups 84 , and each of them is connected to a suitable vacuum line 69 in a normal manner coming from the manifold assembly 68 . The position of the flap folding vacuum cup cross member 82 about the pivots of the pins 79 , which mount members 78 in position is controlled by a control linkage indicated generally at 86 . The control linkage 86 includes a pair of arms 88 , 88 which are fixed to the cross member 70 in a suitable manner. The arms can be welded to the cross member 70 or can be integrally cast with the cross member. The support arms 88 extend away from the plane of the vacuum cups 84 and the carton 11 , and toward the support hub 46 for the slider shaft 42 . The support arms 88 in turn mount a pivoting shaft 90 , at outer end of the arms. The shaft 90 pivots relative to the arms. The shaft 90 forms a bell crank pivot for an arm 92 fixed to one end of the shaft. A pair of long actuator arms are also fixed to the shaft 90 and move when arm 92 pivots the shaft. A short actuator arm 96 is also attached to the shaft 90 and is positioned between support arms 88 . The long actuator arms 92 are pivotally connected to links 98 through a suitable pivot pin 99 . The links have opposite ends connected through pivot pins 100 to brackets 102 fixed to carton flap folding assembly cross member 82 . The actuator arm 92 is operated through the use of a double action fluid pressure actuator 106 , comprising an air cylinder that is mounted at a base end on a support arm 108 . The actuator 106 is held in this position so that it cannot rotate about the pin mounting at the base end. The actuator 106 in turn has an extendible and retractable rod 110 with a rod end 112 that connects through a suitable pin to the actuator arm 92 . In the position shown in FIGS. 2 and 3, the auxiliary carton flap folding vacuum cup lies on a plane with the edges of the vacuum holding cups 72 . When the rod 110 is extended, under suitable control as will be explained, the actuator arm 92 will move forwardly position represented in direction by the arrow adjacent the rod end 112 in FIG. 2, and this will cause shaft 90 to pivot, moving the long actuator arms 94 . The arms 94 pull the link 98 upward to a position wherein the cross member 88 is in the location shown in solid lines in FIG. 3 . This will move the vacuum cups 84 to move substantially 90° and to hold a flap represented in dotted lines in FIG. 3 to a 90° position from the main portion of the carton. This will be done in a desired location during the cycles or rotation of the rotary frame 12 . The pivot axis indicated at 114 in FIG. 3 between the flap folding frame 76 and the support brackets or hubs 74 will be located in a position where axis will lie even with a score line of a carton 11 that is held in the vacuum cups 72 . When the vacuum cups 84 move to the position shown in FIG. 3, the fold will come be made at the score line. It should be noted that the score line is actually offset forwardly (or downwardly) slightly from this pivot, but the score line will fold around the end of the brackets so that a neat, useable fold of the flap indicated at 11 A in FIG. 3 will be made. The short actuator arm 96 is used for controlling a breaker bar 116 pivoted on a shaft 117 that is supported on arms 88 through a link 118 that will push a carton held by the vacuum cups 72 away from these cups at the time of folding the flap and aid in release of the carton when it is in its position adjacent the conveyor as shown in FIG. 6 . The vacuum to the vacuum cups 72 and 84 will be released when the carton is properly placed. The vacuum-fluid pressure manifold assembly 68 is shown in FIGS. 7 through 11. Referring specifically to FIG. 7, the manifold assembly 68 is mounted onto the main shaft 14 , and includes a non-rotatable or stationary hub 170 , which is rotatably mounted on the shaft 14 through a suitable bushing 172 . The hub 170 has an end plate 174 , and a sleeve like hub 176 surrounding the bushing 172 . A thrust bearing 178 is fixed adjacent the end of the shaft 14 and is used for reacting the loads that are created on plate 70 , as will be explained, between the rotating and stationary portions of the manifold assembly 68 . A pressure valve piston 180 is mounted on the interior of an outer support ring or sleeve 182 that is also fixed to the plate 174 on an opposite side from bearing 178 . The sleeve or ring 182 is concentric with and spaced radially outwardly from the hub 176 . The piston 180 has an inner cylindrical surface that rides on the outer surface of the sleeve like hub 176 , and is provided with a pair of O-rings indicated at 184 that are spaced axially, and slidably seal against the hub 176 . The outer surface of the piston 180 is slidably mounted on the interior of the support sleeve or ring 182 and is also sealed relatively to the interior surface of the sleeve 182 with a pair of O-rings shown generally at 186 . The piston 180 is slidably mounted for axially movement in direction along the axis of the shaft 14 , and is held from rotation relative to the hub on a plurality of pins 188 that are fixed in three radial locations around the central axis of the plate 174 . The pins 188 are slidably mounted in suitable receptacles or bores 190 formed in the side of the piston that faces the plate 174 . A spring 192 is mounted on each of these pins 188 and provides a resilient urging tending to move the piston along the inner surface of the sleeve 182 and the outer surface of the hub 176 away from the plate 174 . The hub plate 174 is also used for supporting a vacuum valve ring indicated generally at 198 . The vacuum valve ring 198 includes a low friction material portion 200 , which can be a suitable plastic, and a steel plate 202 that is used for a backing plate. The valve ring 198 is used for providing ports or openings (see FIG. 9) for threading in vacuum fittings. These bores are shown at 202 A and 202 B in FIG. 9, and serve the function of providing a vacuum from a source to the rotating portions of the rotary pick and place unit, as well as providing for a vacuum exhaust. The vacuum valve ring 198 is held from rotation in a suitable manner relative to the hub 170 , and is urged axially away from the plate 174 through the use of springs 204 that are mounted onto pins 205 located radially outwardly from the pins 188 . The vacuum valve ring portion 200 has a pair of part annular slots defined therethrough, and these are on the opposite side of the steel backing plate 202 , as shown generally in FIG. 10, from ports or bores 202 A and 202 B and open to the bores 202 A and 202 B. These slots indicated at 206 , which is a long part annular slot that extends all the way through the unit, and a vacuum relief slot or exhaust slot indicated generally at 208 that is relatively shorter. The surface 201 of the vacuum valve portion 200 , and the surface 181 of the piston 180 face in the same direction and are coplanar in use. Both surfaces 181 and 201 ride against a mating surface 211 of a distribution manifold section 210 that is fixed in position on the shaft 14 and rotates with the shaft. Set screws and a drive key are used for fixing the manifold section in position. For example, set screws 213 can be used for clamping onto the shaft 14 axially. A drive key is used to drive the manifold section. The piston 181 for the pressure actuation is made of a suitable low friction material such as plastic as well, and the distribution manifold section is made of steel but has a smooth surface against which the plastic parts ride to effect a fluid pressure seal as the manifold section rotates with the shaft 14 . The valve slots 202 A and 202 B in the vacuum valve section 200 extend all the way through to the surface 201 , and as will be explained open to suitable ports in the manifold section 210 as the manifold section rotates. As perhaps best seen in FIG. 10, the piston 180 is provided with a number of annular grooves on the surface 181 , that are used for carrying pressure to the manifold section 210 . Since the actuators 106 for actuating are double acting, it is necessary to provide a pressure connection to opposite ends of the actuators. In other words, pressure to a base end of an actuator 106 will cause the rod to extend, but at the same time an exhaust passage has to be provided at the port at the rod end of the actuator 106 . This is done by having a part annular groove for carrying fluid pressure to or permitting pressure to bleed from the base end port of the actuators 106 , and separate part annular groove sections, spaced at a different radial location, for carrying the pressure to or from the rod end of the actuators 106 . As shown in FIG. 10, a first part annular groove section indicated at 214 A is used for permitting air to exhaust from the base end of the cylinders, and is called an “extend” pressure exhaust. This groove 214 A has a number of radially extending passageways 215 that discharge to the periphery of the piston 180 and then are capable of being bled out of the manifold through passageways 216 adjacent the inner diameter of the vacuum valve ring section 200 and its backing plate 202 . On the same radius, but separated therefrom, a second base end groove 214 B is provided in surface 181 as a pressure providing groove for the base end of each of the actuators 106 , and this groove 214 B has a plurality of passageways 217 that extend axially, and as shown in FIG. 7 communicate with a sealed plenum 218 formed within support sleeve 182 and between piston 181 and plate 174 . The plenum 218 is connected to communicate a source of pressure 220 . The groove or recess 214 B is separated from the ends of the groove or recess 214 A with a surface portion 214 C (which is part of surface 181 ) at opposite ends thereof. The grooves 214 A and 214 B are positioned so that there is proper timing for holding the base end of the respective actuators 106 under pressure to extend the appropriate rod for actuating the bracket that controls the auxiliary vacuum cups 82 to pull the carton flap substantially 90° at the proper position. A part annular groove 222 A is formed in piston 180 radially inwardly from the groove sections 214 A and 214 B, and the part annular groove 222 A has a plurality of exhaust passageways indicated at 223 to bleed to the exterior of the piston 180 , and thus also exhaust to the atmosphere when it is desired to extend the rod of the actuator 106 . Annularly aligning (at the same radial position), part annular groove 222 B is the pressure carrying groove for providing pressure to the rod end of the actuators 106 . As can be seen, groove section 222 B is at the same radially distance as the groove section 222 A and has a plurality of pressure ports 224 formed axially in the piston 181 , and leading to plenum 218 and source of pressure 220 . It should be noted that the part annular groove 222 A providing exhaust for the rod end of the actuators 106 , overlaps one portion of the groove section 214 A that provides exhaust for the base end of the actuators in order to obtain proper operation. The positions where pressure is applied to either the rod or the base end of the actuator is also selected by the length of the groove sections 222 A and 222 B. The part annular groove sections 222 A and 222 B are separated by surface portions 225 , to provide a time when there would be no pressure or exhaust provided to the port on the rod end of the actuator. The distribution manifold section 210 for both vacuum and pressure receives the pressure and vacuum from the piston pressure valve 181 and vacuum valve ring 198 , respectively. As shown in FIG. 11, the distribution manifold section 210 , which rotates with the shaft 14 and which has the surface 111 that is formed flat and true and is used as a sealing surface relative to the piston 181 and vacuum valve 198 is provided with three vacuum outlet ports indicated generally at 230 A, 230 B and 230 C, and each of these ports is made for use with one of the actuators 106 and the associated vacuum cups. The vacuum ports 230 A, 230 B and 230 C are each connected through a radial bore 231 A, 231 B and 231 C to the exterior or peripheral surface 232 of the distribution manifold section. Additionally, the distribution manifold section 210 has a set of retract pressure ports which essentially are rod end pressure ports 234 A, 234 B and 234 C, which are the same radial distance out from the center of shaft 14 as the respective groove portions 222 A and 222 B on the piston pressure valve 180 . That means that as the piston pressure valve 180 is held stationary and the distribution manifold section rotates past the groove sections 222 A and 222 B, the ports 234 A, 234 B and 234 C will alternately be provided with fluid under pressure from the source 220 through the piston grooves and as they rotate past groove section 222 B will be permitted to exhaust to atmosphere through the radial passages 223 that open to the groove section 222 A. The outer ends of each of the radial bores 235 A, 235 B and 235 C, which are open to the ports 234 A- 234 C is provided with a threaded outer end for attaching suitable pressure lines such as that shown at 236 through a suitable fitting. There are separate pressure lines to each of the passageways 235 A- 235 C leading to a separate one of the actuators 106 for the separate vacuum cup assemblies. The base ends of each of the actuators 106 is provided with the fluid under pressure, or connection to exhaust passageways through a plurality of axially extending ports 238 A, 238 B and 238 C that are spaced radially outwardly from the center of rotation of the shaft 214 a greater distance than the ports 224 , so that the ports 238 align with the part annular grooves 214 A and 214 B. The ports 238 A- 238 C are connected to radial passageways 239 A, 239 B and 239 C that have threaded ends for connection to suitable threaded fittings such as that shown at 240 , which provide pressure lines connected to the base ends of the respective actuators 106 . Since the distribution manifold section 210 rotates with the shaft 214 , it also rotates with the frame that supports the vacuum cup assemblies, so that the transfer of fluid pressure between the stationary member and the rotating member occurs right at the interface between the surfaces 181 and the surface 211 . By having the part annular grooves 214 A and 214 B for connection to the base end of the actuators 106 , and the grooves 222 A and 222 B connected to the rod end of the actuators, and then having the arcuate length of the grooves properly arranged for the three ports 234 A- 234 C and 238 A- 238 C, respectively, the actuators can be operated at the desired position during the cycles of rotation of frame 12 to pick up a carton, and at the appropriate position the actuator will be extended to cause the auxiliary vacuum cups to “break” or move the flap of a carton to its appropriate position. The manifold assembly 68 carries both vacuum and pressure, across the same interface surface. This is aided in part by having the vacuum acting at a greater radius from the center of rotation of the stationary and rotating members, than the pressure. The total axial force from the pressure acting in the grooves 214 B and 222 B is counteracted by the force acting on the piston 180 from chamber 218 . The pressure in the chamber 218 is the same as that in the grooves 214 A and 222 A but the area of the back side of the piston is greater than the area of the part annular grooves. Thus the pressure in the chamber urges the surfaces of the piston and the manifold section together. The vacuum force and the differential pressure force will keep the system sealed, but springs 192 and 204 are used for assuring sealing is maintained. The vacuum is supplied to the vacuum cups at the appropriate time to pick up the cartons, during a portion of the rotary cycle, and release the vacuum at an appropriate time so the cartons will be deposited on the conveyor appropriately. The present rotary placer is the first to use pneumatic or air pressure for operating actuators, carried by the rotary device, and at the same to carrying vacuum to vacuum cups for operation. It should be noted that the hub plate 174 has a recess for permitting a vacuum fitting to be attached directly to the vacuum port of the steel backing plate of the vacuum valve ring. In FIGS. 6 and 7, the carton handling assembly is shown moved from a pick position wherein all of the vacuum cups 84 and 72 are on a plane to the place position. As can be seen in FIG. 6, the cups are connected with vacuum lines 69 that come from the manifold assembly 68 . In FIG. 4 the carton handling components are shown in approximately the position for picking up a carton at a carton store. FIG. 6 is a perspective view with the carton handling assembly 40 after rotating from the pick position to the place position. The auxiliary or flap folding vacuum cups have moved 90° to hold a flap 11 A that is shown only schematically on one part, with the main part of the carton held as shown with a fragmentary portion 11 B. In FIG. 6, the conveyor chain 160 for a carton loading machine 162 is shown, and a guide or pusher 163 as illustrated. The flap would be lifted to its folding position for transporting by the conveyor 160 . Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.

A vacuum holder for use with an automated carton erecting and packing line and mountable on a rotary carton placer for removing cartons into which product is to be placed includes vacuum cup for removing a carton from a store of cartons. The cartons including a foldable flap. The vacuum holder includes a set of vacuum cups that will engage a flap and at an appropriate time in the carton erection sequence will be positively actuated under control of a power actuator to fold the flap to a desired position prior to depositing the carton on a conveyor line. A rotary manifold carries both vacuum for vacuum cups holding the carton, and fluid pressure for the power actuators to the rotating carton placer.

BACKGROUND OF THE INVENTION This invention relates to therapeutic tables, or beds, and more particularly, to a kinetic therapeutic table which reciprocally rotates a patient support from one side to the other and which is otherwise adjustable. Kinetic therapeutic tables which slowly, reciprocally rotate a patient support to cause different parts of the patient's anatomy to support his weight are well known. Such kinetic therapeutic tables are intended for use by patients who are incapable of substantial voluntary movements. The voluntary movements needed to eliminate the formation of bedsores, lung congestion, venal thrombosis and other maladies which develop from immobility are substituted by periodic movements of the therapeutic table. Examples of such therapeutic tables are shown in U.S. Pat. Nos. 2,076,675 (Sharp); 2,950,715 (Brobeck); 3,434,165 (Keane); 3,748,666 (Seng); 4,107,490 (Keane); 4,175,550 (Leininger et al.) and 4,277,857 (Svehaug). Since the patient support is tilted, it is necessary to provide lateral support to secure the patient against falling off the bed. The lateral supports must fit snugly to the patient's body and must therefore be adjustable for proper fit with various patients of different size. In the bed of Keane 3,434,165, elongate, upstanding side members provide lateral support. These are mounted by means of depending shafts which fit into tubular receivers, or mountings, which in turn are fastened to the underlying patient support. While the tubular receivers are laterally adjustable, the location of the inner side of the lateral support which presses against the patient is not adjustable relative to the tubular mountings. In addition to lateral support, it is also sometimes necessary to provide means for restraining the patient's knee against movement above the patient support and means to support the patient's foot. In patent No. 3,434,165 (Keane), for instance, such a knee restraint and foot support are mounted to the ends of separate L-shaped members which are mounted to, and extend upwardly from, a central portion of the frame to which the patient support is mounted. This inconveniently also places the adjustment mechanisms for the knee restraint and the foot support in the central portion of the table where it is relatively more difficult to reach by attendants, particularly if they are of short stature. In addition, this central protrusion requires the patient support to be centrally divided. It is also known to provide the patient support in the form of multiple panels which can be individually moved away from beneath the patient to gain access for treatment, bathing or the like. In Keane 3,434,165 these panels are hinged to a central portion of the frame. Thus, although the panels are movable for access, they are not easily removable entirely from the frame. Such non-removability is desirable for cleaning of the panel and for better access and for situations in which the panel is not needed for supporting the patient, as in the case of an amputee. In addition, complete removability permits easy substitution of special purpose panels which may be required. For purposes of improving access to the patient, it is also desirable to stop the movement of the bed at any selected non-horizontal position. However, it is also necessary to quickly move the bed to a horizontal position in the event of an emergency. It is also important to be able to switch off power to the motor which provides the rotary drive to the motor at any angular position of the bed in the event of shorting or other malfunction of the motor. In Keane 4,107,490, a power off switch is provided in a kinetic therapeutic table, but it is mechanically prevented from being activated to terminate power to the rotary drive motor except when the bed is in one of certain preselected positions. Once locked in one of these positions, the bed can only be moved to a horizontal position by disengaging the patient support from the drive by means unassociated with the position locking means. A further problem with known kinetic therapeutic beds which move the patient about a pivot axis aligned with the elongate axis of the table is that the patient support is located beneath the pivot axis. Accordingly, instead of the patient support rotating, it unpleasantly swings or sways. It is known to provide a pivot axis aligned with the patient support in a therapeutic table which tilts or rocks about an axis transverse to the elongate direction of the patient support, as shown in U.S. Pat. No. 4,277,857. However, the problem is not alleviated, since the patient's head and feet are still caused to swing because of their substantial distance from the pivot axis. In known therapeutic tables which rotate about an axis aligned with the elongate direction of the pivot axis, such as shown in (Keane) 3,434,165 and (Leininger et al.) 4,175,550, the pivot axis is undesirably located above the patient support. A movable drive support is needed to mount the patient support for rotary movement relative to the frame which provides a smooth and steady movement with minimum noise. In the aforementioned beds, the patient supports are simply mounted to narrow pivot axles at opposite ends. This disadvantageously places all the weight of the patient and patient support on the narrow axles. If the narrow pivot axles are driven directly, they provide little mechanical advantage. If the bed is driven by an eccentic cam spaced from the axle, then non-uniform drive movement is developed. In U.S. Pat. No. 3,302,218 (Stryker), a rotatable bed is shown supported by an annular member, but no drive is associated with the annular member, and it is disadvantageously located intermediate the ends of the patient support. In addition to rotary movement about an elongate axis, it is also desirable to be able to pivot or tilt the bed about an axis extending substantially transverse to the rotary axis. When the patient is tilted to a position with his head at a level beneath the level of his feet, the patient is said to be in a Trendelenburg position, and when he is in a position with his feet lower than his head, he is in a reverse Trendelenburg position. Devices which provide for this type of movement for a patient support are known as illustrated by U.S. Pat. Nos. 2,076,675 (Sharp); 3,434,165 (Keane); 3,525,308 (Koopmans et al.) and 4,277,857 (Svehaug). In Sharp 2,076,675 and Keane 3,325,308 the beds also rotate. In the device of Svehaug 4,277,857, a diagonal track provided at opposite ends of the bed is employed to alternately raise and lower the two ends. However, a single drive is provided for continuous rocking movement of the patient support, and independent control of movement of the two ends of the bed is not obtainable. Generally, while known devices perform somewhat satisfactorily, they employ structure which have a high profile or are unduly heavy or mechanically complex. It is also desirable to adjust the degree of maximum tilt imparted to the patient support. In known therapeutic tables such adjustment is limited to a few selected discrete angles of tilt and such adjustment is accomplished by mechanical means. SUMMARY OF THE INVENTION Thus, the principal object of the present invention is to provide an improved kinetic therapeutic table which overcomes the disadvantages in prior therapeutic tables and the like noted above. In keeping with this objective, a therapeutic table having a frame and an elongate patient support mounted to the frame is provided with an improved adjustable lateral support assembly for holding a portion of the patient's body against lateral movement. The assembly comprises an elongate lateral support member which is substantially symmetrical with respect to an elongate central axis thereof, a mounting member attached to the support member and having a connection portion at a location offset laterally from the central axis, and means for releasibly attaching the connection portion of the mounting member to the bed. Preferably, the releasible attaching means is also adjustably mounted, so that the position of the lateral support member can be laterally adjusted for patients of different size. The adjustable lateral support assembly of the invention provides an additional degree of adjustment. Adjustment is achieved by disconnecting a pair of substantially identical, lateral support members from the bed and then reconnecting them to the bed in the opposite positions that they were previously connected, with their previously inwardly facing sides facing outwardly. The pair of lateral support members are mirror images of one another with regard to their offset connection portions. Accordingly, interchanging their positions results in an adjustment of the lateral position of the lateral support member surfaces which are closest to the patient by an amount equal to the lateral offset of the connection portion. Another important advantageous feature of the present invention is the provision of a therapeutic table having an improved knee restraint assembly which more conveniently places the adjustment mechanism therefore adjacent the side of the bed, rather than closer to the central portion of the bed which makes access more difficult. This also avoids the placement of a mounting bracket protruding centrally from the patient support. The improved knee restraint assembly comprises a knee restraint member, means for mounting the knee restraint member to a lateral support member in a position overlying a knee area of the patient's support and means for mounting the lateral support member to the frame. The lateral support member is located alongside the bed rather than in a central portion. Advantageously, it serves the dual functions of providing lateral support to a patient and providing a mounting means for the knee restraint member. In keeping with the advantages obtained in the foregoing knee restraint assembly, the objective of the present invention is also partially achieved by means of provision of an improved foot support assembly in a therapeutic table. Like the knee restraint assembly, the foot support assembly employs the lateral support member for mounting purposes. The improved foot support assembly of the invention comprises a foot support member for supporting a patient's foot, means for mounting the foot support member to the lateral support member and means for mounting the lateral support member to the frame. Thus, when both knee restraint and foot support members are provided, the lateral support member serves triple functions of laterally supporting the patient, mounting the foot support member and mounting the knee restraint member. In a preferred embodiment, a single track is attached to the top surface of the lateral support, and this single track is used for adjustably mounting both the foot support and knee restraint members at selected fixed positions therealong. The objective of providing an improved therapeutic table is further achieved in the present invention through means of an improved panel mounting mechanism for a plurality of panels which compose the patient's support. Unlike known therapeutic tables comprised of a plurality of panels in which the panels are movable for access but not removable, in the present invention the improved panel mounting mechanism provides for easy and complete removal of the panels to facilitate access and cleaning. In addition, the improved mounting mechanism provides for easy substitution of one panel mounting mechanism for another. Briefly, the improved panel mounting mechanism comprises a connector member mounted to one of the frame and one side of the panel, means connected to the other of the frame and the one side of the panel for receipt of the connector member for support of the panel at that one side, another connector member, means for mounting the other connector member to the panel adjacent another side thereof for movement relative to the panel, means connected to the frame for receipt of the movably mounted connector members to support the panel at the other side and means connected with the movable connector member and manually engageable to move the movable connector member into and out of supportive receipt within the movable connector member supporting means. In a preferred embodiment, a pair of pins and a pair of movable pins are provided as connector members, and a single handle is used both to effectuate the movable pin removal and to serve as a handle for holding the panel during its removal. In this preferred embodiment, the method of removing the panel, comprises the steps of actuating the handle to move the movable pin out of supportive connection with the frame and holding the panel by the handle while moving the panel away from the frame to move the other pin out of supportive connection with the frame. The objective of providing an improved kinetic therapeutic bed is additionally achieved by means of an improved drive control assembly which, in addition to providing rotary drive for the patient support, will also hold the patient support in any selected position for improved access to the patient. In addition, means are provided for quickly releasing the hold on the patient support to enable prompt movement thereof to a horizontal position in the event of an emergency. The improved drive control assembly of the present invention thus comprises means engageable with a motor through a unidirectional driving gear and connected with the patient support for transmitting the power from the motor to rotate the patient support, means for moving the motor and power transmitting means into and out of engagement with one another and a switch for terminating electrical power to and stopping the rotation of the motor at any position of the patient's support. The unidirectional driving gear and power transmitting means act together when engaged to hold the patient support at any position it is in when the motor stops. Disengagement of the power transmitting means and unidirectional driving gear, on the other hand, causes release of the hold on the patient support to enable movement thereof to a substantially horizontal position. In a preferred embodiment, the drive train employs a driving gear, such as a worm gear, which cannot be driven, so that when the motor is turned off, the one way driving gear is stationary and cannot be turned by forces applied to the patient support. Advantageously, the switch can be actuated at any position of the patient support to stop the bed at any position instead of only at a few preselected positions as in the aforementioned therapeutic tables. A further advantageous feature of the therapeutic table of the present invention is the provision of an improved drive control assembly which simultaneously provides for disengagement of the motor and drive system to permit manual rotation of the patient support to a horizontal position and for automatic actuation of means for locking the patient support in a preselected position when the motor is disengaged. Specifically, the improved drive control assembly comprises means for disengaging the motor from the patient support to remove rotary power therefrom and stop movement of the patient support, means, when actuated, for locking the patient support in a preselected position and means associated with the disengaging means for actuating the locking means when the motor is disengaged. In a preferred embodiment, movement of a manual lever provide force for both disengaging the motor from the patient support and moving a locking pin, or other member, against a drive ring in the path of a pin hole therein. When the patient support and drive ring are rotated to the horizontal position, then the locking pin springs into the pin hole and prevents further movement of the patient's support until it is removed. The locking pin is automatically removed from the pin hole upon movement of the lever to again engage the motor with the patient support. Yet a further advantageous feature of the present invention is the provision of a kinetic therapeutic table comprising a substantially planar patient support frame, a patient support mounted to the frame for supporting a patient on a surface thereof and means for mounting the patient support to the frame for rotary movement relative thereto by an elongate pivot axis substantially aligned with the patient support surface. Unlike known therapeutic tables in which the pivot axis is located above the patient support, undesirable swinging movement of the patient support surface is eliminated. In addition, this enables locating the center of gravity of the combined patient and patient support and support frame substantially at the pivot axis to reduce the average moment arm and the amount of power needed to rotate the patient support and patient. In addition, the need for a keel or counterbalance weight is reduced or eliminated which, in turn, permits locating the patient support at a lower height, such as thirty inches, which is more in keeping with the standard height for hospital beds required to facilitate easy access to the patient. Still another important advantageous feature of the present invention is an improved patient support and drive assembly which rotates the patient support of a kinetic therapeutic bed with a smooth and steady movement and with minimum noise or slippage. These features are achieved in an improved patient support and drive assembly for a therapeutic table comprising a first connector assembly including a pivot axle and a pivot axle connector for pivotally mounting one end of the bed to one end of the frame, a second connector assembly for pivotally mounting the other end of the patient support to the frame including a circular drive ring, means for fixedly attaching the other end of the patient support to the drive ring to rotate therewith and means for mounting the drive ring to the frame for rotary movement relative thereto about an axis of rotation substantially aligned with said pivotal axle and means connected with the drive ring and the frame of the therapeutic table for driving the ring for rotation relative to the frame. In a preferred embodiment, the first connector includes a ball and mating socket for a relative universal movement therebetween and the drive ring has a diameter on the order of the width of the frame to provide a substantial gear reduction relative to the driving means. Preferably, the drive ring mounting means includes an idler wheel mounted to the frame and in underlying supportive engagement with the circumference of the drive ring. Also, in the preferred embodiment, a locking mechanism holds the motor in engagement with the drive train to prevent slippage or hopping and to ensure good smooth uniform motion. The objective of the present invention is further achieved by provision of an improved adjustable patient support mounting assembly for a therapeutic table having a frame and a patient support. This support mounting assembly is provided to pivot, or tilt, the bed about an axis substantially transverse of the rotary axis or to raise and lower either or both ends of the bed to achieve a Trendelenburg or reverse Trendelenburg position for the patient. The improved assembly comprises a track with a horizontal portion and an upturned portion, a first element movably mounted to the upturn portion of the track for movement therealong, a second element movably mounted to the horizontal portion of the track for movement therealong, means located substantially within the track for flexibly linking the first and second elements, means for driving the second element along the horizontal portion of the track and means for connecting one end of the patient support to the first element for movement therewith. The connecting means moves the one end of the patient support to raise or lower the one end. In a preferred embodiment two such adjustable mounting assemblies are provided at opposite ends of the bed which are individually controllable. This arrangement enables a lower profile for the table and eliminates dangerously accessible linkage arms. Still a further objective of the present invention is provision of a control for a therapeutic table which enables easy electronic adjustment of the degree of tilt of the patient support to any selected angle. In a preferred embodiment, this is achieved by providing means for establishing a first time period of rotation in one direction, means for establishing a second time period of rotation in the opposite direction and means for controlling the application of power to the drive motor to alternately cause it to rotate in the two opposite directions during the first and second time periods respectively. Each of the two time periods are independently adjustable to achieve any degree of maximum tilt within a preselected range. BRIEF DESCRIPTION OF THE DRAWINGS Further objects, features and advantages will be made apparent and the foregoing objects, features and advantages will be described in greater detail in the following detailed description of the preferred embodiment which is given with reference to the several views of the drawing, in which: FIG. 1 is a side elevation of the therapeutic table of the present invention with a lower portion of the same partially broken away; FIG. 2 is a top view of the therapeutic table; FIG. 3 is a top view of the therapeutic table without padding and the support frame partially broken away; FIG. 3A is an enlarged side elevation of the improved mounting mechanism for the removable panels of the therapeutic table; FIG. 4 is an enlarged partially broken cross-sectional view of the drive mechanism of the therapeutic table taken along view line IV--IV of FIG. 1; FIG. 5 is a partially broken cross-sectional side view of the drive mechanism taken along view line V--V in FIG. 4 including housing and hand lever arm; FIG. 6 is an enlarged partially broken away perspective view of one adjustable patient support mounting assembly; FIG. 6A is a partially broken away perspective view of the upper flexible linkage and connector frame of adjustable patient support mounting assembly; FIG. 7 is a partially broken view of the drive mechanism similar to that of FIG. 4 but with the drive mechanism disengaged; FIG. 8 is an enlarged end view of the knee support assembly of the therapeutic table; FIG. 9 is an enlarged end view of the foot support assembly of the therapeutic table; FIG. 10 is a perspective view of a portion of the therapeutic table in a tilted position and with one leg panel removed; FIG. 11 is another perspective view of a portion of the therapeutic table in a titled position; FIG. 12 is a cross-section of the improved lateral support assembly as taken along view line XII--XII of FIG. 10; FIG. 13 is a top view of the patient support frame of the therapeutic table; FIG. 14 is a side elevation of the patient support frame of FIG. 13; FIG. 15 is a side elevation of the adjustable support mechanism for altering the longitudinal tilt of the patient support of the therapeutic table; and FIG. 16 is a schematic circuit diagram of the motor control circuit of the therapeutic table. DETAILED DESCRIPTION As seen in FIG. 1, therapeutic table 10 includes substantially planar base frame 12 and a patient support 14 rotatably mounted to base frame 12. Patient support frame 14 includes padding 15 providing patient support surface 17 to support the patient. Patient support frame 14 is rotatably mounted to base frame 12 by first connector assembly 16. First connector assembly 16 comprises a pivot axle or ball 19 received by a pivot connector mating socket 21 for relative universal movement therebetween, thereby providing a rotatable connection of head portion 18 of patient support 14 to base frame 12. Foot portion 20 of frame 14 has a second connector assembly including a circular drive ring 22, which can be seen in FIG. 4. Ring 22 is fixedly mounted to patient support 14 and is contained in drive housing 24. Mounting means, idler support wheels or roller members 26, as seen in FIG. 4, are rotatably mounted to frame 12. Ring 22 rests on roller members 26 providing underlying support of the circumference of ring 22 and permitting rotational movement of foot portion 20 with respect to frame 12 about an axis of rotation substantially aligned with first connector assembly 16, as seen in FIG. 1. The pivot axis of the therapeutic table 10 is defined by the first connector assembly 16 and the axis of rotation of ring 22. The center of gravity of the combined base frame 12 and patient support frame 14 is a preselected distance below the pivot axis. This distance is substantially reduced by adding a patient of average weight and, as a result, the total combined center of gravity is closely aligned to the pivot axis. Therapeutic table 10 has improved driving means 30 which provides power to rotate patient support 14. Driving means 30, as seen in FIGS. 4, 5 and 7, includes electric motor 28 which in turn rotates worm gear 40 and, in turn, gear or sprocket 32 which is in rotative engagement therewith. Sprocket 32 is linked to drive ring 22 providing a power transmitting means, as described in more detail below, for rotating patient support 14 between selected angular positions as desired for optimum treatment of the patient. The linkaqe between sprocket 32 and drive ring 22 or power transmitting means includes sprocket 32 mounted to shaft 34 which is rotatably mounted to shaft frame 36. Shaft frame 36 is fixedly attached to platform 38 which, in turn, is fixedly interconnected to base frame 12. When sprocket 32 is engaged to worm gear 40 of electric motor 28 shaft 34 is rotatably moved. Sprocket 42 being fixedly attached to shaft 34, in turn, rotates. Drive chain 44 engages sprocket 42 and a similar transmission sprocket 46. Transmission sprocket 46 is fixedly mounted to rotatable shaft 48. Rotatable shaft 48 is rotatably mounted to housing 24. Thus, as drive chain 44 rotates transmission sprocket 46, rotatable shaft 48 rotates transmission sprocket 50 which is fixedly attached to shaft 48. Transmission sprocket chain 52 is engaged to gear teeth 54, disposed on the circumference of circular drive ring 22 and to transmission sprocket 50. As a result of the rotation of transmission sprocket 50, circular drive ring 22 rotates supplying rotational movement to patient support 14. Drive ring 22 has a diameter on the order of the width of patient support frame 14 to provide a substantial gear reduction relative to the driving means. The improved drive control also includes means for moving electric motor 28 into engagement and disengagement with the above power transmitting means. As seen in FIG. 5, a hand operated lever 56 is mounted to shaft 58 which in turn has cam 60 fixedly attached thereto. As seen in FIGS. 4 and 5, electric motor 28 is pivotably connected to fixed frame 62 by pivot connector 64. Electric motor 28 rests upon movable motor platform 66. Movable motor platform 66 is movably mounted to platform 38 by spring connector 68. Referring to FIG. 4, when worm gear 40, which is a unidirectional driving gear, is engaged with sprocket 32, movable motor platform 66 rests upon platform 38. Spring 70 of spring connector 68 is in a tension position supplying a downward force on worm gear 40, assisting engagement with sprocket 32. Further, assistance in maintaining engagement between worm gear 40 and sprocket 32 is provided by hooks 72 mounted to shaft 58. As seen in FIG. 4, hooks 72 push downwardly on movable motor platform 66, in turn, pulling worm gear 40 into sprocket 32. When disengagement of worm gear 40 is desired, lever 56 is activated rotating cam 60, as seen in FIG. 7, removing hooks 72 from movable motor platform 66 and pushing movable motor platform 66 upwardly. This upward movement disengages worm gear 40 from sprocket 32 and removes the driving power to patient support 14. Drive control assembly further includes a switch for terminating electrical power to electric motor 28. When power is terminated to electric motor 28, worm gear 40 remains engaged to sprocket 32 and because it is a unidirectional driving gear it PG,16 holds patient support 14 in any position it was in when electric motor 28 stops. If desired, worm gear 40 may then be disengaged from sprocket 32, thereby releasing patient support 14 to be easily hand moved to a preselected position. An often desired preselected position for patient support 14 is substantially horizontal. To lock patient support 14 into this position when worm gear 40 is disengaged from sprocket 32, locking means 74, as seen in FIG. 7, comprising a second locking element or spring loaded pin 76 engaging first locking element or aperture 78 defined in circular drive ring 22 is provided. Means associated with the above described means for disengaging worm gear 40 to sprocket 32 is also provided. This associated means includes frame 80 pivotally mounted onto pin 82, as seen in FIGS. 4 and 7. Spring loaded pin 76 is mounted to frame 80, as shown in FIG. 5. A second spring loaded pin 84, as seen in FIG. 4, rests on housing 24 and biases frame 80 from housing 24. Associated means also provides bar 86 mounted to frame 80, as seen in FIGS. 4, 5 and 7. Bar 86 is positioned beneath cam 60. When worm gear 40 is engaged with sprocket 32, second spring loaded pin 84 pushes bar 86 against cam 60. In this position, spring load pin 76 is positioned above and not in contact with circular drive ring 22. However, when worm gear 40 is disengaged from sprocket 32 by cam 60, as seen in FIG. 7, cam 60, at the same time, pushes downwardly on bar 86. Spring load pin 76, if not positioned directly over aperture 78, is then compressed into circular drive ring 22. Patient support 14 may be then easily hand moved until pin 76 aligns with aperture 78, at which point, pin 76 will self activate and engage aperture 78. Thus, attendant need not visually align pin 76 and aperture 78, but merely move patient support until pin 76 self engages aperture 78 and locks patient support 14 into desired position. Therapeutic bed 10 provides completely removable panels 88, in patient support 14, as viewed in FIGS. 3 and 10. Panels 88, when removed, allow anterior access to the patient and permit a wide range of movement of specific patient limbs when desired. Panels 88 are mounted to patient support 14 by an improved mounting mechanism 90, as seen in FIGS. 3 and 3A. Mounting mechanism 90 comprises a pair of spaced pins 92 which can be mounted to one side of panels 88 and received by receiving means or apertures 94 which can be located in patient support 14. Alternately, spaced pins 92 can be mounted to patient support 14 and apertures 94 can be located in panels 88. Either arrangement provide support of one end of panels 88. Another pair of movable pins 96 are mounted to panels 88, spaced apart and located on adjacent sides of panels 88 to where pins 92 are located. Pins 96 are supported by receiving means or apertures 98 in patient support 14. When pins 92 and 96 are received by their corresponding apertures 94 and 98, panels 88 are secured to patient support 14. Movable pins 96 have means connected thereto to move pins 96 into and out of receipt with apertures 98. These means comprise bracket 99 for supporting pins 96 in sliding engagement with panels 88, seen in FIGS. 3 and 3A. Lever arm 100 is rotatably mounted to panel 88 by pivot connector 102. Bracket 104 is mounted to lever arm 100 and rotates when lever arm 100 is rotated. Pins 96 are mounted to bracket 104 by hook portions 106 of pins 96 received by openings 108 of bracket 104. Thus, simple hand turning of lever arm 100 rotates bracket 104 which slides pins 96 inwardly or outwardly, as desired. As a result, panels 88 can be easily removed from patient support 14 by removing movable pins 96 from apertures 98 by actuating lever arm 100 and sliding panel 88 away from frame 14 by maintaining grasp on lever arm 100. Therapeutic table 10 provides an improved lateral support assembly for holding a portion of the patient's body against lateral movement in at least one direction. It is desired, to keep patient's legs in close proximity to outer leg support 110 and inner leg support 112, as seen in FIG. 2. This arrangement prevents any radical movement of the patient's legs when patient support 14 is rotating. Similarly, the patient's thoraxic portion of the body needs lateral support which is provided by thoraxic supports 114. Since body dimensions vary from one patient to another, the distance between supports 110 and 112, as well as between supports 114, must be adjustable. As viewed in FIGS. 2 and 11, supports 110, 112 and 114 are elongated members which are substantially symmetric along a longitudinal central axis thereof. Supports 110, 112 and 114 are generally padded for contacting the patient's body. As viewed in FIG. 2, inner leg supports 112 are adjustable by providing bracket 116 mounted to adjustment rail 118 by hand clamp 120. Vertical posts 122 are mounted to bracket 116 and engage ring members 124 that are mounted to inner leg supports 112. This engagement allows inner leg support 112 to be rotated about posts 122 when hand clamp 120 is secured in any desired position along opening 123 of adjustment rail 118. At the lower end of inner leg supports 112, bracket 126 is movably mounted to adjustment rail 118 by hand clamp 128. Bracket 126 has two pairs of vertical posts 130, mounted thereto. Each pair of posts 130 slidably hold inner leg support 112. Hand clamp 128 may be secured in any desired position along opening 132 of adjustment rail 118. Inner leg supports 112 can be moved closer together or further apart by positioning hand clamps 120 and 128 along adjustment rail 118. The improved lateral support assembly further includes the mounting of outer leg supports 110 and thoraxic supports 114. In FIG. 2, slots 133 are provided through padding 15 and panels 88. In FIG. 12, mounting member 134 is attached to a support member, i.e., outer leg or thoraxic, at one end and engaged to attaching means 136 in slot 133 at the other end. Mounting member 134 comprises a post 138 mounted substantially vertical and substantially in the longitudinal axis of support 114. Connector plate 140 attaches connection portion or post 142, offset laterally and in a downward direction, to post 138. Post 142 is received by attaching means 136. Attaching means 136 includes tube 144 disposed in slot 133 which slidably receives post 142. The lower end of tube 144 is mounted to foot plates 146 which transverse slot 133, and on the inner portion of the lower end of tube 144 is mounted threaded collar 148. Threaded collar 148 threadingly receives threaded member 150. Threaded member 150 projects through slot 133 and through bearing plates 152 which transverse slot 133. Lower portion of threaded member 150 has cam lever 154 rotatably attached thereto. Cam lever 154 has a cam surface 156 of varying radii of curvature which contacts bearing plates 152. With this improved lateral support assembly outer leg and thoraxic supports 110 and 114, respectively, may be adjustably moved to fit the patient's body in two ways. First, attaching means 136 may be moved along slot 133 to a desired position and locked. The releasing or locking of attaching means 136 occurs by moving cam lever 154. Moving cam lever 154 in one direction pushes camming surface 156 onto bearing plates 152, which creates a downward pulling force on threaded member 150 clamping foot plates 146 to panel 88. Moving cam lever 154 in the opposite direction causes camming surface 156 to be removed from bearing plates 152 thereby removing a downward pulling force on foot plates 146. This permits mounting member 134 and attaching means 136 to be moved along slot 133. Secondly, outer leg supports 110 can be interchanged with each other. This will place supports 110 closer or further away from the outside portion of patient support 14 because of the offset construction of mounting member 134. Similarly, this can be done with outer leg supports 110. As viewed in FIG. 2, positioned at the outside edge of patient support 14 and across from each thoraxic support 114 is rail 158. Rail 158 prevents the arms of the patient from moving off of patient support 14. Rails 158 are slidingly received by receptacles 159 for easy mounting and removal of rails 158, as seen in FIG. 1. Adjustable shoulder supports 160, as seen in FIGS. 1 and 2, are mounted by telescopic tubes 162 and 164. Tubes 162 and 164 slide into and out of each other and can position shoulder supports 160 horizontally where desired and locked by clamp 166. Shoulder supports 160 are positioned just above the patient's shoulders to prevent a severely injured patient from inadvertently sitting up. Tube 164 is fixedly mounted to collar 168, as seen in FIG. 2. Collar 168 is rotatably attached to cross bar 170. In turn, cross bar 170 is fixedly mounted to bracket 172 of patient support 14. Clamps 174 are provided on collars 168 to secure or release, as desired, collars 168 for rotational movement to cross bar 170. This construction allows each shoulder support 160 to be individually rotated toward or away from patient as needed. Lateral head supports 176, as seen in FIGS. 1 and 2, are provided, particularly, for patients that will be in head traction. Lateral head supports 176 are adjustable horizontally along tube 162 by typically a screw clamp. Lateral head support 176 is also adjustable vertically in relation to tube 162. Typically this vertical adjustment is accomplished by a screw clamp which is received by a slotted bracket 178 which holds lateral head support 176 to tube 162. Since lateral head supports 176 are mounted to tube 162, supports 176 can be individually rotated up and away from or down and toward the patient as the shoulder supports 160 described above. In FIGS. 2 and 8, is shown an improved knee restraint 180 which includes knee restraint member 182 movably mounted to outer leg support 110. Outer leg support 110 has means for mounting to patient support 14 as described earlier. Knee restraint member 182 is generally needed to be positioned in close proximity over the patient's knee joint. Therefore, knee restraint member 182 is mounted to outer leg support 110 for horizontal adjustment over patient support 14 and easy access by attendant. Means for mounting member 182 to support 110 comprises track 184 disposed in an upper portion or surface of outer leg support 110 and hand clamp 186 carried by track 184. Hand clamp 186 has bracket 188 attached thereto, as viewed in FIG. 8. In turn, bracket 188 has adjustable bracket 190 attached thereto by hand clamp 192 to which knee restraint member 182 is fixedly attached. Hand clamp 186 can be loosened to slide the knee restraint assembly horizontally over patient support 14 to the desired location and then tightened. Knee restraint member 182 is placed vertically in close proximity to patient's knee by loosening hand clamp 192 and sliding adjustable bracket 190 along slot 194 defined therein. Knee restraint member, for example, can be moved from first position 196, as seen in FIG. 8, to a second position 198. When knee restraint member 182 is in a desired vertical position, hand clamp 192 is then secured thereby firmly securing adjustable bracket 190 to bracket 188. In FIGS. 2 and 9, is shown an improved foot support assembly 200 comprising foot support member 202 movably mounted to outer leg support 110 for easy attendant access. Outer leg support 110 has means for mounting to patient support 14 as described earlier. Foot support member 202 is generally positioned to abut the lower portion of the patient's foot. Therefore, foot support member 202 has means for mounting to outer leg support 110 for horizontal adjustment over patient support 14. This mounting means includes track 184 disposed in an upper portion or surface of outer leg support 110 and hand clamp 204 carried by track 184. Hand clamp 204 has bracket 206 attached thereto, as seen in FIG. 9. In turn, bracket 206 is fixedly attached to foot support member 202. Hand clamp 204 can be loosened to slide foot support member horizontally over patient support 14 to the desired location and tightened. In FIGS. 1, 13, 14 and 15, is shown a means for raising a patient to a sitting up position and lowering the same to a prone position. In FIGS. 13 and 14, is shown a double-hinged support frame 208. Frame 208 is shown as part of the lower portion of patient support 14 in FIG. 1. Frame 208 has a lower rigid frame 210 and an upper-hinged frame 212 mounted thereto. Foot end 214 of hinged frame 212 is fixedly attached to lower frame 210. Head end 216 of hinged frame 212 is hinged to foot end 214 by hinges 218. Thus, head end 216 can be rotated, as seen in FIG. 14, for example, between a first position 220 and a second position 222. In FIGS. 1 and 15, is shown the mechanism for raising and lowering as well as locking head end 216 of frame 208. Railing 224 is attached to the exterior side portion of lower rigid frame 210, as seen in FIG. 1. Similarly, railing 226 is attached to the exterior side portion of the head end 216 of upper-hinged frame 212. Track 228 is mounted to railing 224, as shown in FIGS. 1 and 15. Hand clamp 230 is carried in track 228 and at the same time, is pivotally connected to lever arm 232. Lever arm 232 is pivotally connected at its other end to railing 226 by pivot connection 233. This described mechanism is also identically located on the opposite side of therapeutic table 10. As a result of this mechanism, the patient can be easily raised and secured in numerous sitting up positions, as well as, lowered to a prone position. For example, in FIG. 15, hand clamp 230 can be loosened from track 228 in its first position 234 and pushed along track 228 to a second position 236. This movement of hand clamp 230 causes lever arm 232 to raise the head end 216 from a first position 238 to a second position 240. At this point, hand clamp 230 can be tightened to secure head end 216 in desired second position 240. Similarly, this process is reversed and head end 216 can be lowered and secured. Improved adjustable patient support mounting assembly 242 can be seen in FIGS. 1 and 6. Assembly 242 includes base frame 12 having tracks 244 disposed along its lower portion. Tracks 244 have a horizontal portion 246 and an upturned portion 248. First element 250 is movably mounted to the upturned portion 248, and second element 252 is, likewise, movably mounted to horizontal portion 246. Means 254 is located substantially in tracks 244 for flexibly linking first and second elements 250 and 252. First element 250 comprises bar 255 having a wheel 256 rotatably and pivotally mounted to each end of bar 255. Similarly, second element 252 comprises bar 258 having a wheel 256 rotatably and pivotally mounted to each end of bar 258. Means 254 found between first and second elements 250 and 252 is similarly bars 260 and 262, as seen in FIG. 1, each of bars 260 and 262 are rotatably and pivotally mounted to a wheel 256 located at each end of said bars. Bars 255, 260, 262 and 258 are successively pivotally linked at a wheel 256, as viewed in FIG. 1. Wheels 256 are disposed in tracks 244 and allow this flexible linkage to move along horizontal portion 246 and upturned portion 248 of track 244. Assembly 242 provides a driving means 264 for second element 252 which includes electric motor 266. Electric motor 266 has a drive shaft 268 joined to threaded drive shaft 272 by mating cylinder or coupling 270. Cross shaft 274 is fixedly mounted to second elements 250 and, likewise, fixedly attached to ball screw 276. Ball screw 276 is substantially parallel to horizontal portion 246 and ball screw 276 along with coupling 270 are located between tracks 244. Ball screw 276 is threadingly engaged to shaft 272. When electric motor 266 is activated, shaft 272 rotates in one direction causing ball screw 276 to travel along shaft 272. As a result, second element 250 is moved along track 244. When electric motor 266 is activated in the reverse direction, shaft 272 rotates in this reverse direction causing ball screw 276 to travel along shaft 272 in the opposite direction as first described. When electric motor 266 is turned off, ball screw 276 holds its position on shaft 268. As seen in FIG. 6A, first elements 250 are pivotally connected to frame 278. Frame 278 has mating socket 21 of connector assembly 16 mounted to the top portion of frame 278. Thus, when electric motor 266 is activated, head portion 18 of patient support 14 is raised or lowered to place the patient in various Trendelenburg positions. The above described adjustable patient support mounting assembly 242 is, likewise, located at the opposite end of frame 12 which is the same end as foot portion 20 of patient support 14. The only difference between this assembly and the previously described assembly is that the corresponding first element 250 being third element is mounted to the foot portion 20 of patient support 14 by connecting means. The remainder of the apparatus corresponds to that which was described above such as second element 252 is fourth element etc. The two above described adjustable patient support mounting assemblies 242 work independently of one another. Thus, head portion 18 of patient support 14 can be raised and lowered as desired by actuating electric motor 266, and foot portion 20 can so, likewise, be raised and lowered by activating electric motor 280. The movement of the patient support is controlled by a motor control circuit shown in FIG. 16. Generally, the control circuit operates as follows. After limit switches LS1 through LS4 and CLS are closed and a start switch 300 is closed, the bed will start to tilt to the right for a time period set by a tilt right potentiometer which will be described hereinafter. When the timer period lapses, a stop timer is activated which stops all motion for a set period of time by terminating power to the motor. After the stop timer period has lapsed, a direction control logic circuit changes the direction of the motor, and the patient support will return toward a zero point, or horizontal position. As it crosses the zero point, the limit switch CLS will close and trigger a tilt left timer. The patient support will then tilt to the left for a time period set by a tilt left potentiometer. When this time period has lapsed, the stop timer is triggered, and the motor again stops. After the stop timer period lapses, the direction logic circuit will again change the rotary direction of the motor which causes the patient support to return to the zero point. After the patient support crosses the zero point, the above cycle is repeated, so long as power is applied to the system. Advantageously, the time periods are selectively variable to selectively alter the degree of maximum tilt of the patient support. If at any time the rotation limits are exceeded, or if the head or foot of the bed is raised, at least one of limit switches LS1, LS2, LS3 and LS4 will open to cause termination of electrical power to the motor. If the patient support is not in its horizontal position, the control circuit will not allow the motor to start. Referring to FIG. 16, the electrical motor control circuit has thirteen functional subcircuits, as follows: an input switch debouncing circuit 302, a limit switch logic circuit 304, a start latch circuit 306, a zero detect and crossing logic circuit 308, a tilt left timer circuit 310, a tilt right timer circuit 312, a stop timer circuit 314, a direction control logic circuit 316, a direction relays and drivers circuit 318, a motor control relay and drivers circuit 320, a motor direction and snubber circuit 322, an on indicator circuit 324 and a power supply circuit (not shown). The operation of these circuits are described below in the order listed. In the input switch debouncing circuit, all external switches 302, CLS, LS1, LS2, LS3 and LS4 have one side connected to ground, so that when they are switched to a closed position, as shown, a logic 0-state signal is produced on the other side of the switch. Each of the other sides of these switches are connected to identical debouncing circuits to prevent the adverse effect of contact bounce. Each of the debouncing circuits comprises a capacitor 306 connected to ground and a resistor 308 with one side connected to the switch and capacitor 306 and the other side connected to a positive power supply voltage VS, such as 5 volts DC. This results in production of a logic 1-state signal at the juncture of resistor 306 and 308 whenever the associated switch is open. Each of the outputs of switches CLS, LS1, LS2, LS3 and LS4 are connected to the input of an associated inverting Schmidt trigger 310 to provide additional noise immunity. These Schmidt triggers 310 produce logic 1-state signals on their outputs 312, 314, 316, 318 and 320 when the associated switches are closed. These outputs 312-320 are connected to the limit switch logic circuit 304. They are logically conjuncted by means of AND gates 322, 324 and 326. The output of AND gate 326 produces a 1-state signal on its output 328 when all of the limit switches are in a closed position, as shown, indicating a safe condition for operation. In the event that any one of the limit switches is open, the AND gate 328 will produce a 0-state signal on its output to prevent operation. The output 328 is connected to a reset input 330 of a timer circuit 332 configured as a latch. A trigger input 336 of timer circuit 332 is connected to the momentary contact start switch 302 through its associated debouncing circuit. The timer circuit 332 latches in response to a 0-state signal at its trigger input 336 to produce a logic 1-state signal on its output 334 so long as the reset input 330 is being provided with a logic 1-state enable signal. In the event the 1-state signal is removed from the reset input 330, such as occurs when any of the limit switches are opened, then the output 334 is switched to a logic 0-state to stop the motor. In order for the application of electrical power to the motor to begin rotation of the patient support, the patient support must be in a horizontal position, as detected by the switch CLS. Switch CLS is a normally open switch held closed when the patient support is at a horizontal position. When this condition is met, a 1-state logic signal is developed on output 312 of circuit 302. This results in the development of a 1-state signal at the input of a flip-flop 338 of zero detect and crossing logic circuit 308 and at the input of an AND gate 340 of this same circuit. When the start switch 302 is actuated, a 1-state signal is developed at output 334 of circuit 306. This 1-state signal is also applied to the inputs of three AND gates 340, 342 and 344. The 1-state signal applied to the input of AND gate 340 causes its output to switch to a 1-st-ate which triggers the flip-flop 338 to cause its output 348 to also switch to a 1-state. The 1-state signal from AND gate 340 is also inverted by an inverter 350, and the resultant 0-state signal produced on the output of inverter 350 is supplied to and triggers the tilt left timer circuit 310 and the tilt right timer circuit 312. As stated, the output 348 is also connected to an input of AND gate 342. When a 1-state signal is applied to AND gate 348 at the same time that a 1-state signal is applied to its other input 350 from output 334 of circuit 306, the output 352 of AND gate 342 switches to a 1-state. This 1-state signal is applied to an input 354 of an AND gate 356. The other input to AND gate 356 is coupled to output 334 of circuit 306, and if both inputs are in a logic 1-state, AND gate 356 switches its output 358 to a logic 1-state. The 1-state signal on output 358 is applied to an inverter 360 which inverts the 1-state signal and produces 0-state signal on its output 362. This 0-state signal is coupled to an OR gate 364 of the motor control relay and drivers circuit 320. Output 348 of flip-flop 338 will remain in a logic 1-state as long as output 328 of AND gate 326 and output 334 of circuit 306 remain in a logic 1-state. If at any time either of these outputs switch to a 0-state, then the flip-flop is cleared and an output 348 of flip-flop 338 switches to a 0-state. This causes the output 352 of AND gate 342 to switch to a 0-state. This, in turn, causes the output 358 of AND gate 356 to switch to a 0-state, and output 362 to switch to a 1-state. The tilt left timer circuit 310 is used to generate a 1-state signal for a period of time determined by a capacitor 364 and a potentiometer 366. With a one megaohm potentiometer and a one hundred microfarad capacitor, the time period is variable from one to ninety seconds. This variable time period is established by a timer 368 which is triggered by a negative going pulse and its trigger input 370. This pulse is generated by a capacitor 372 connected in series with the output of inverter 350. Thus, the timer 368 is triggered by the start switch 302 or by detection of a zero crossing by means of the circuitry of start latch circuit 306 or zero detect and crossing logic circuit 308, as described above. The timer 368 is reset by means of a logic signal applied to its reset input 374 from the direction control logic circuit 316. The tilt right timer circuit 312 is identical to the tilt left circuit 310 and functions in an identical fashion. It comprises a capacitor 374, a potentiometer 376, a timer 378 having an input 380 coupled to the output of inverter 350 through a capacitor 382. These elements respectively correspond to elements 364, 366, 368, 370 and 372 of the tilt left circuit 310 described above. The stop timer circuit 314 stops the motor for a period of time determined by a potentiometer 384 for a variable time period between zero and ten seconds. This causes the patient support to come to a complete stop before changing directions. A timer 386 is triggered by a negative going pulse generated from a capacitor 388 connected in series with the output of an OR gate 390 which comprises the stop timer circuit 314. The inputs to OR gate 390 are respectively connected to the outputs 392 and 394 of the tilt left timer circuit 310 and the tilt right timer circuit 312. When both of these inputs to OR gates 390 are in 0-state, the output of OR gate 390 switches to a 0-state which is coupled through capacitor 388 to trigger timer 386. The output 396 of timer 386 is connected to an inverter 398 of direction control logic circuit 316. It is also connected to the other input of OR gate 364 of motor control relay and drivers circuit 320. The output of inverter 398 is connected to a clock input 400 of a flip-flop 402 of the direction control logic circuit 316. The direction control logic circuit 316 comprises a D-type flip-flop having an inverting output 404 connected to its D input 406. In this configuration, the inverting output 404 and the non-inverting output 408 alternately switch between logic 1-states and logic 0-states with each clock pulse applied to input 400. The output 396 of stop timer 386 is connected to the clock input 400 through inverter 398. Accordingly, the flip-flop 402 is caused to change states in response to lapse of the timing period of the stop timer. Output 408 of timer 402 is coupled to the reset input 374 of timer 368 of the tilt left timer circuit 310. The output 406 of timer 402 is coupled to the reset input 374 of timer 368 of the tilt left timer circuit 310. When output 400 switches to a logic 0-state, one or the other of tiers 378 or 368 is triggered depending on which output 408 or 404 is in a logic 1-state. The direction relays and driver circuit 318 comprises a plurality of inverters 410, 412, 414 and 416 which respectively drive coils 418, 420, 422 and 424. These relays are energized by a logic 0-state at their inputs and are commonly connected to DC power supply source VS. Relays 418 and 420 are associated with means for controlling the motor to cause the patent support to tilt right, and relay coils 422 and 424 are associated with relays which cause the patient support to tilt left. The inputs to inverters 410 and 412 are obtained from inverting output 404 of flip-flop 402. The inputs to inverters 414 and 416 are coupled to the non-inverting output 408 of flip-flop 402. Thus, either relay coils 418 and 420 are energized or relay coils 422 and 424 are energized, but all four coils are never energized at the same time. The motor control relay and drivers circuit 320, as previously indicated, drives a relay coil 426. When relay coil 426 is energized, its associated relay switch 426-1 causes connection of AC power from a suitable source 428 to one side of relay contacts 422-1 and 418-1 respectively associated with relay coils 422 and 418 and to one side of relay contacts 424-1 and 420-1 respectively associated with relay coils 424 and 420. Thus, when relay coil 426 is energized, the motor 28 will operate in a rotary direction determined by the direction control flip-flop 402. If the relay coils 418 and 420 are energized, then relay contacts 422-1 and 418-1 are closed and the motor rotates in the direction to tilt the patient support to the right. On the other hand, if relay coils 422 and 424 are energized, then the motor will rotate in a direction to cause the patient support to tilt to the left. Relay coil 426 is energized when a 0-state signal is developed on the output of OR gate 364. As previously indicated, both inputs to OR gate 364 must be in a 0-state in order for a 0 -state signal to be produced on its output. Thus, if a logic 1-state signal is produced on output 362 of the zero detect and crossing logic circuit 308, indicating that the patient support is not at a horizontal position, the motor will not be energized. Likewise, during the tie period of the stop timer 386, a logic 1-state signal applied to the input of OR gate 364 will prevent the motor from being energized. The motor direction and snubber circuit 322 functions to reverse the direction of the motor by reversing the connection of motor leads 430 and 432 in a well-known manner. Lead 430 is connected to the hot side of the AC power source 428 and the lead 432 is connected to the neutral, or cold, side of the AC power source 428. When the relay contacts 418-1 and 420-1 are closed, a lead 434 of motor 28 is connected to a capacitor 436 and a lead 438 is connected to the neutral side of AC power source 428. On the other hand, when relay contacts 422-1 and 424-1 are closed, lead 438 is connected to capacitor 436 and the hot side of AC power source 428, and lead 434 is coupled to the neutral side of AC power source 428. A capacitor 440 and a resistor 444 connected in series across the AC power supply 428 functions as a snubber. The ON indicator circuit comprises an LED 444 which is energized when a 1-state signal is generated on the output 334 of start latch circuit 306. The 1-state signal on output 334 is inverted by an inverter 446 which drives the LED 444 through a resistor 448. The power supply circuit for the control of FIG. 15 is not shown since it is of any conventional design. Preferably, it produces a regulated 5-volt DC supply as voltage supply voltage VS. It should be understood that the above description is exemplary and variations may be made without departing from the scope of the invention defined in the following claims.

A kinetic therapeutic table 10 having a frame 12, a planar patient support 14 mounted to the frame 12 for rotation about an elongate axis substantially aligned therewith and adjustable vertically at its foot 20 and head 18 ends. Symmetrical lateral support packs 114 at opposite sides of the patient's torso have laterally offset mountings for adjustment of the width therebetween by reversing their locations. Outer lateral leg supports 110 are mounted to the frame 12 and have a track 184 at their top surface fo slideable mounting of both knee restraints 182 and foot supports 202 at selected positions therealong. The patient support 14 comprises a planar frame with a plurality of panels 88 removably mounted thereto by means of pins 96 actuated by a lever arm 100. A patient support 14 drive motor 28 provides rotary drive to the patient support 14 through a worm gear 40 locked to a gear linkage, so that it may be stopped and held by the worm gear 40 in any angular position by switching power off to the motor 28. The worm gear 40 is manually disengageable from the remainder of the gear linkage to enable manual movement of the patient support 14 to a horizontal position. A locking pin 76 is automatically biased against a drive ring 22 and springs into a pin hole 78 therein when the horizontal position is reached. The patient support 14 is mounted at one end of its pivot axis to the frame 12 by a ball 19 and socket 21 connection. The other end is connected to the drive ring 22 which is rotatably mounted to the frame 12 by means of idler wheels 26 and is otherwise rotatably driven by the motor 28 through the gear linkage. A electronic control circuit controls application of power to the motor 28 for selectively adjustable periodic movement of the patient support 14.